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The thermoelectric (TE) phenomena are intensively explored by the scientific community due to the rather inefficient way energy resources are used with a large fraction of energy wasted in the form of heat. Among various materials, mixed ion-electron conductors (MIEC) are recently being explored as potential thermoelectrics, primarily due to their low thermal conductivity. The combination of electronic and ionic charge carriers in those inorganic or organic materials leads to complex evolution of the thermovoltage (Voc) with time, temperature, and/or humidity. One of the most promising organic thermoelectric materials, poly(3,4-ethyelenedioxythiophene)-polystyrene sulfonate (PEDOT-PSS), is an MIEC. A previous study reveals that at high humidity, PEDOT-PSS undergoes an ionic Seebeck effect due to mobile protons. Yet, this phenomenon is not well understood. In this work, the time dependence of the Voc is studied and its behavior from the contribution of both charge carriers (holes and protons) is explained. The presence of a complex reorganization of the charge carriers promoting an internal electrochemical reaction within the polymer film is identified. Interestingly, it is demonstrated that the time dependence behavior of Voc is a way to distinguish between three classes of polymeric materials: electronic conductor, ionic conductor, and mixed ionic–electronic conductor
We report spectroelectrochemical studies to investigate the charge storage mechanism of composite polypyrrole/lignin electrodes. Renewable bioorganic electrode materials were produced by electropolymerization of pyrrole in the presence of a water-soluble lignin derivative acting as a dopant. The resulting composite exhibited enhanced charge storage abilities due to a lignin-based faradaic process, which was expressed after repeated electrochemical redox of the material. The in situ FTIR spectroelectrochemistry results show the formation of quinone groups, and reversible oxidation-reduction of these groups during charge-discharge experiments in the electrode materials. The most significant IR bands include carbonyl absorption near 1705 cm(-1), which is attributed to the creation of quinone moieties during oxidation, and absorption at 1045 cm(-1) which is due to hydroquinone moieties.
Biological adhesives are materials of particular interest in the fields of bio-inspired technology and antifouling research. The adhesive of adult barnacles has received much attention over the years; however, the permanent adhesive of the cyprid - the colonisation stage of barnacles - is a material about which very little is presently known. We applied confocal laser-scanning microscopy to the measurement of contact angles between the permanent adhesive of barnacle cyprid larvae and self-assembled monolayers of OH- and CH3-terminated thiols. Measurement of contact angles between actual bioadhesives and surfaces has never previously been achieved and the data may provide insight into the physicochemical properties and mechanism of action of these functional materials. The adhesive is a dual-phase system post-secretion, with the behaviour of the components governed separately by the surface chemistry. The findings imply that the cyprid permanent adhesion process is more complex than previously thought, necessitating broad re-evaluation of the system. Improved understanding will have significant implications for the production of barnacle-resistant coatings as well as development of bio-inspired glues for niche applications.
The controlled filling of hydrophobic nanoporous surfaces with hydrophilic molecules and their wetting properties are described and demonstrated by using thiocholesterol (TC) self-assembled monolayers (SAMs) on gold and mercaptoundecanoic acid (MUA) as the filling agent. A novel procedure was developed for filling the nanopores in the TC SAMs by immersing them into a "cocktail" solution of TC and MUA, with TC in huge excess. This procedure results in an increasing coverage of MUA with increasing immersion time up to an area fraction of similar to 23%, while the amount of TC remains almost constant. Our findings strongly support earlier observations where linear omega-substituted alkanethiols selectively fill defects (nanopores) in the TC SAM (Yang et al. Langmuir 1997, 12, 1704-1707). They also support the formation of a homogeneously mixed SAM, given by the distribution of TC on the gold surface, rather than of a phase-segregated overlayer structure with domains of varying size, shape, and composition. The wetting properties of the Filled SAMs were investigated by measuring the most stable contact angle as well as contact angle hysteresis. It is shown that the most stable contact angle is very well described by the Cassie equation, since the drops arc much larger than the scale of chemical heterogeneity of the SAM surfaces. In addition, it is demonstrated that contact angle hysteresis is sensitive to the chemical heterogeneity of the surface, even at the nanometric scale.
In laboratory-based biofouling assays, the influence of physico-chemical surface characteristics on barnacle settlement has been tested most frequently using the model organism Balanus amphitrite (= Amphibalanus amphitrite). Very few studies have addressed the settlement preferences of other barnacle species, such as Balanus improvisus (= Amphibalanus improvisus). This study aimed to unravel the effects of surface physico-chemical cues, in particular surface-free energy (SFE) and surface charge, on the settlement of cyprids of B. improvisus. The use of well-defined surfaces under controlled conditions further facilitates comparison of the results with recent similar data for B. amphitrite. Zero-day-old cyprids of B. improvisus were exposed to a series of model surfaces, namely self-assembled monolayers (SAMs) of alkanethiols with varying end-groups, homogenously applied to gold-coated polystyrene (PS) Petri dishes. As with B. amphitrite, settlement of cyprids of B. improvisus was influenced by both SFE and charge, with higher settlement on low-energy (hydrophobic) surfaces and negatively charged SAMs. Positively charged SAMs resulted in low settlement, with intermediate settlement on neutral SAMs of similar SFE. In conclusion, it is demonstrated that despite previous suggestions to the contrary, these two species of barnacle show similar preferences in response to SFE; they also respond similarly to charge. These findings have positive implications for the development of novel antifouling (AF) coatings and support the importance of consistency in substratum choice for assays designed to compare surface preferences of fouling organisms.
In neutron scattering studies of soft matter, a diverse array of methods and instruments are used, providing information on structure and dynamics on various length and energy scales. However, much of the infrastructure needed for neutron scattering is common for many instruments. After a brief historical retrospect of neutron scattering, this chapter introduces the basic infrastructure needed to conduct scattering experiments. This includes equipment that is used to produce, spectrally adjust and purify, and to deliver neutrons to the instruments where scattering experiments are conducted. The basics of the interaction of neutrons with matter is also introduced, as a preparation for the final sections on the different means at hand for neutron detection.
Hydrogels are used to enhance biocompatibility and reduce inflammation in biomedical applications, and as area-enlarging matrices in bioanalytical devices. For either of these applications, the structure of the hydrogel is important for the function, and thus structural understanding of hydrogels in their wet state is highly relevant for the use and development of these materials. Also, processing of these materials is frequently made in ambient air, and it is of interest to relate the properties of dry, or humid air-swollen hydrogels, to their wet properties.
We use neutron reflectometry to follow the swelling of hydrogels in air of controlled humidity. Comparing hydrogels prepared on silica and gold substrates { both of relevance to bioanalytical applications { we observe that the swelling is different, reflecting a structural difference between these polymers, but that the water content of the polymer films near saturation is near 33% in both cases. Upon immersion in water, the swelling is estimated to approximately 2 x the dry thickness of the polymer, though a consistent quantitative determination of the polymer profile could not be made. Finally, we observe that the hydrogels are unaffected by either positively and negatively charged proteins.
Self-assembled monolayers (SAMs) of galactoside-terminated alkanethiols have protein-resistance properties which can be tuned via the degree of methylation [Langmuir 2005, 21, 2971-2980]. Specifically, a partially methylated compound was more resistant to nonspecific protein adsorption than the hydroxylated or fully methylated counterparts. We investigate whether this also holds true for resistance to the attachment and adhesion of a range of marine species, in order to clarify to what extent resistance to protein adsorption correlates with the more complex adhesion of fouling organisms. The partially methylated galactoside-terminated SAM was further compared to a mixed monolayer of omega-substituted methyl- and hydroxyl-terminated alkanethiols with wetting properties and surface ratio of hydroxyl to methyl groups matching that of the galactoside. The settlement (initial attachment) and adhesion strength of four model marine fouling organisms were investigated, representing both micro- and macrofoulers; two bacteria (Cobetia marina and Marinobacter hydrocarbonoclasticus), barnacle cypris larvae (Balanus amphitrite), and algal zoospores (Ulva linza). The minimum in protein adsorption onto the partially methylated galactoside surface was partly reproduced in the marine fouling assays, providing some support for a relationship between protein resistance and adhesion of marine fouling organisms. The mixed alkanethiol SAM, which was matched in wettability to the partially methylated galactoside SAM, consistently showed higher settlement (initial attachment) of test organisms than the galactoside, implying that both wettability and surface chemistry are insufficient to explain differences in fouling resistance. We suggest that differences in the structure of interfacial water may explain the variation in adhesion to these SAMs.
Self-assembled monolayers (SAMs) are widely used in science and engineering, and recent progress has demonstrated the utility of zwitterionic peptides with alternating lysine (K) and glutamic acid (E) residues for antifouling purposes. Aiming at developing a peptide-based fouling-resistant SAM suitable for presentation of surface-attached pheromones for barnacle larvae, we have investigated five different peptide SAMs, where four are based on the EK motif, and the fifth was designed based on general principles for fouling resistance. The SAMs were formed by self-assembly onto gold substrates via cysteine residues on the peptides, and formation of SAMs was verified via ellipsometry, wettability, infrared reflection-absorption spectroscopy and cyclic voltammetry. Settlement of cypris larvae of the barnacle Balanus (=Amphibalanus) amphitrite, the target of pheromone studies, was tested. SAMs were also subjected to fouling assays using protein solutions, blood serum, and the bacterium Mycobacterium marinum. The results confirm the favorable antifouling properties of EK-containing peptides in most of the assays, although this did not apply to the barnacle larvae settlement test, where settlement was low on only one of the peptide SAMs. The one peptide that had antifouling properties for barnacles did not contain a pheromone motif, and would not be susceptible to degredation by common serine proteases. We conclude that the otherwise broadly effective antifouling properties of EK-containing peptide SAMs is not directly applicable to barnacles, and that great care must be exercised in the design of peptide-based SAMs for presentation of barnacle-specific ligands.
Nanoscale Surface Self-Assembly (EuChem Conference, June 19-23, 2005, Sigtuna, Sweden
Identification of settlement cues for marine fouling organisms opens up new strategies and methods for biofouling prevention, and enables the development of more effective antifouling materials. To this end, the settlement behaviour of zoospores of the green alga Ulva linza onto cationic oligopeptide self-assembled monolayers (SAMs) has been investigated. The spores interact strongly with lysine- and arginine-rich SAMs, and their settlement appears to be stimulated by these surfaces. Of particular interest is an arginine-rich oligopeptide, which is effective in attracting spores to the surface, but in a way which leaves a large fraction of the settled spores attached to the surface in an anomalous fashion. These 'pseudo-settled' spores are relatively easily detached from the surface and do not undergo the full range of cellular responses associated with normal commitment to settlement. This is a hitherto undocumented mode of settlement, and surface dilution of the arginine-rich peptide with a neutral triglycine peptide demonstrates that both normal and anomalous settlement is proportional to the surface density of the arginine-rich peptide. The settlement experiments are complemented with physical studies of the oligopeptide SAMs, before and after extended immersion in artificial seawater, using infrared spectroscopy, null ellipsometry and contact angle measurements.
We recently reported oil the strong interactions of zoospores of the green alga, Ulva linza with all arginine-rich oligopeptide self-assembled monolayer (SAM) [Biofouling 2008, 24, 303-312], where the arginine-rich peptide induced not only high spore settlement, but also a form of abnormal settlement, or "pseudo-settlement", whereby it proportion of spores do not go through the normal process of surface exploration, adhesive exocytosis, and loss of flagella. Further. it was demonstrated that both the total number of settled spores and the fraction of pseudosettled spores were related to the surface density of the arginine-rich peptide. Here we present a further investigation of the interactions of zoospores of ulva with a set of oligomeric, de nom designed, arginine-rich peptides, specifically aimed to test the effect of peptide primary structure on the interaction. Via variations in the peptide length and by permutations in the amino acid sequences, we gain further insight into the spore-surface interactions. The interpretation of the biological assays is supported by physicochemical characterization of the SAMs using infrared spectroscopy, ellipsometry, and contact angle measurement. Results confirm the importance of arginine residues for the anomalous pseudosettlement, and we found that settlement is modulated by variations in both the total length and peptide primary structure. To elucidate the Causes of the anomalous settlement and the possible relation to peptide-membrane interactions, we also compared the settlement of the "naked" zoospores of Ulva(which present it lipoprotein membrane to the exterior without a discrete polysaccharide cell wall), with the settlement of diatoms (unicellular algae that are surrounded by it silica cell wall), onto the peptide SAMs. Cationic SAMs do not notably affect settlement (attachment), adhesion strength, or viability of diatom cells, Suggesting that the effect of the peptides on zoospores of Ulva is mediated via specific peptide-membrane interactions.
Structural properties of Aerosol-OT (AOT) foam films were studied by neutron reflectometry. The drainage of large (10 cm(2)), horizontally oriented AOT films under zero applied external pressure is slow and proceeds from thick colored or gray films to black films of approximately 200 Angstrom thickness over many hours, resulting in quasi-static conditions over the time scales required for the acquisition of reflectivity profiles throughout the whole drainage process. After formation of the foam film-while still showing colored interference fringes-and during the early stages of thinning, the appearance of Bragg diffraction peaks demonstrates that the film contains multilamellar structure, in agreement with studies at free air/water interfaces. Upon further reduction of the film thickness, below approximately 250 Angstrom, the reflectivity profile is well fitted by a three-layer slab model with two surfactant layers and an aqueous core with a high surfactant content. The composition of the aqueous core and the manner in which the reflectivity during the latter stages of draining evolves from Bragg peaks to a Kiessig fringe structure indicate stratification within the thin foam film.
Hydrogels are widely used in biomedicine and for bioanalytical purposes, normally under wet conditions. For certain applications, processing steps, or process monitoring, hydrogel films are used or treated under ambient conditions, and because they are hygroscopic, it is of interest to investigate how they respond to changes in atmospheric humidity. We have used neutron reflectometry to follow the swelling of thin UV-polymerized hydrogel films in air under different relative humidities (RHs). These polymers were prepared to similar thicknesses on silica and gold substrates, and the chemical similarity between them was verified by infrared spectroscopy. The swelling in response to variations in RH was different for the layers on the two substrate types, reflecting structural changes induced by differences in the UV exposure required to achieve a given polymer thickness, as demonstrated also by differences in the Flory-Huggins interaction parameter, obtained by fitting a Flory-Huggins-type sorption model to the swelling data. Wetting studies show small changes in contact angles with surrounding humidity variations, indicating that structural reorganization at the interface in response to humidity changes is limited.
This work describes the fabrication, characterization, and protein adsorption behavior of charged polymer gradients. The thin gradient films were fabricated by a two-step technique using UV-initiated free-radical polymerization in a reactor with a moving shutter. A homogeneous layer of cationic poly(2-aminoethyl methacrylate hydrochloride) was first formed, followed by a layer of oppositely charged poly(2-carboxyethyl acrylate) with a continuously increasing thickness. Adsorption from protein solutions as well as human blood plasma was investigated by imaging surface plasmon resonance and infrared microscopy. The results showed excessive protein adsorption in the areas where one of the polymers dominated the composition, while there was a clear minimum at an intermediate position of the gradient. The charge of the surface was estimated by direct force measurements and found to correlate well with the protein adsorption, showing the lowest net charge in the same area as the protein adsorption minimum. We therefore hypothesize that a combination of the charged polymers, in the right proportions, can result in a protein-resistant surface due to balanced charges.
The ability to produce monomolecular coatings with well-defined structural and functional properties is of key importance in biosensing, drug delivery, and many recently developed applications of nanotechnology. Organic chemistry has proven to be a powerful tool to achieve this in many research areas. Herein, we present the synthesis of three oligo(lactosides) glycosylated in a (1 → 3) manner, and which are further functionalized with amide-linked short alkanethiol spacers. The oligosaccharides (di-, tetra-, and hexasaccharide) originate from the inexpensive and readily available lactose disaccharide. These thiolated derivatives were immobilized onto gold surfaces, and the thus formed self-assembled monolayers (SAMs) on planar gold were characterized by wettability, ellipsometry and infrared reflection–absorption spectroscopy. Further, the ability of these SAMs to stabilize gold nanoparticles in saline solutions was also demonstrated, indicating that the oligosaccharides may be used as stabilizing agents in gold nanoparticle-based assays.
We describe the synthesis of a series of mono-, di-, and trisaccharide-functionalized alkanethiols as well as the formation of fouling-resistant self-assembled monolayers (SAMs) from these. The SAls,,Is were characterized using ellipsometry, wetting measurements, and infrared reflection absorption spectroscopy (WAS). We show that the structure of the carbohydrate moiety affects the packing density and that this also alters the alkane chain organization. Upon increasing the size of the sugar moieties (from mono- to di- and trisaccharides), the structural qualities of the monolayers deteriorated with increasing disorder, and for the trisaccharide, slow reorganization dynamics in response to changes in the environmental polarity were observed. The antifouling properties of these SAMs were investigated through protein adsorption experiments from buffer solutions as well as settlement (attachment) tests using two common marine fouling species, zoospores of the green macroalga Ulva linza and cypris larvae of the barnacle Balanus amphitrite. The SAMs showed overall good resistance to fouling by both the proteins and the tested marine organisms. To improve the packing density of the SAMs with bulky headgroups, we employed mixed SAMs where the saccharide-thiols are diluted with a filler molecule having a small 2-hydroxyethyl headgroup. This method also provides a means by which the steric availability of sugar moieties can be varied, which is of interest for specific interaction studies with surface-bound sugars. The results of the surface dilution study and the low nonspecific adsorption onto the SAMs both indicate the feasibility of this approach.
An understanding of the doping and ion distributions in light-emitting electrochemical cells (LECs) is required to approach a realistic conduction model which can precisely explain the electrochemical reactions, p-n junction formation, and ion dynamics in the active layer and to provide relevant information about LECs for systematic improvement of function and manufacture. Here, Fourier-transform infrared (FTIR) microscopy is used to monitor anion density profile and polymer structure in situ and for time-resolved mapping of electrochemical doping in an LEC under bias. The results are in very good agreement with the electrochemical doping model with respect to ion redistribution and formation of a dynamic p-n junction in the active layer. We also physically slow ions by decreasing the working temperature and study frozen-junction formation and immobilization of ions in a fixed-junction LEC device by FTIR imaging. The obtained results show irreversibility of the ion redistribution and polymer doping in a fixed-junction device. In addition, we demonstrate that infrared microscopy is a useful tool for in situ characterization of electroactive organic materials.
The technology of an immunoassay detection platform is critical to clinical disease diagnoses, especially for developing a medical diagnostic system. A polymer-based immunoassay platform was fabricated on nonwoven fabric polypropylene (PP) using a photografting reaction to graft 2-hydroxyethyl methacrylate (HEMA) and sulfobetaine (SBMA). The antifouling properties of PP-g-P(HEMA-co-SBMA) were investigated by fibrinogen adsorption and platelet adhesion. Carbonyldiimidazole was employed to activate the pendant hydroxyl groups in HEMA moieties and covalently coupled antibody molecules. The detection of the limit of the immunoassay platform was as low as 10 pg/mL. Antibody amount and bioactivity affected the availability of antibody and the sensitivity of immunoassay. The immune efficiency was dependent on the strategies of antibody immobilization. The immune efficiency of Au-g-P(SBMA-co-HEMA) and Au-SH surfaces measured by QCM-D was 165% and 35.7%, respectively. The covalently binding antibody via hydrophilic polymer chains as spacers could retain fragment antigen-binding up orientation, maintain the bioactivity of antibody, and mainly improve the accessibility of antibody molecules via adjusting the conformations of polymer chains when the antibodies recognized the antigens. Therefore, grafting hydrophilic polymers, such as zwitterionic PSBMA and reactive PHEMA onto nonwoven fabric PP, and binding antibody by covalent strategy had the potential to be developed as a commercial immunoassay platform.
The rapid growth of wearables has created a demand for lightweight, elastic and conformal energy harvesting and storage devices. The conducting polymer poly(3,4-ethylenedioxythiophene) has shown great promise for thermoelectric generators, however, the thick layers of pristine poly(3,4-ethylenedioxythiophene) required for effective energy harvesting are too hard and brittle for seamless integration into wearables. Poly(3,4-ethylenedioxythiophene)-elastomer composites have been developed to improve its mechanical properties, although so far without simultaneously achieving softness, high electrical conductivity, and stretchability. Here we report an aqueously processed poly(3,4-ethylenedioxythiophene)-polyurethane-ionic liquid composite, which combines high conductivity (>140Scm(-1)) with superior stretchability (>600%), elasticity, and low Youngs modulus (<7MPa). The outstanding performance of this organic nanocomposite is the result of favorable percolation networks on the nano- and micro-scale and the plasticizing effect of the ionic liquid. The elastic thermoelectric material is implemented in the first reported intrinsically stretchable organic thermoelectric module. Though deformable thermoelectric materials are desirable for integrating thermoelectric devices into wearable electronics, typical thermoelectric materials are too brittle for practical application. Here, the authors report a high-performance elastic composite for stretchable thermoelectric modules.
We demonstrate a convenient chip platform for the addressable immobilization of protein-loaded vesicles on a microarray for parallelized, high-throughput analysis of lipid-protein systems. Self-sorting of the vesicles on the microarray was achieved through DNA bar coding of the vesicles and their hybridization to complementary strands, which are preimmobilized in defined array positions on the chip. Imaging surface plasmon resonance in ellipsometric mode was used to monitor vesicle immobilization, protein tethering, protein-protein interactions, and chip regeneration. The immobilization strategy proved highly specific and stable and presents a mild method for the anchoring of vesicles to predefined areas of a surface, while unspecific adsorption to both noncomplementary regions and background areas is nonexistent or, alternatively, undetectable. Furthermore, histidine-tagged receptors have been stably and functionally immobilized via bis-nitrilotriacetic acid chelators already present in the vesicle membranes. It was discovered though that online loading of proteins to immobilized vesicles leads to cross contamination of previously loaded vesicles and that it was necessary to load the vesicles offline in order to obtain pure protein populations on the vesicles. We have used this cross-binding effect to our benefit by coimmobilizing two receptor subunits in different ratios on the vesicle surface and successfully demonstrated ternary complex formation with their ligand. This approach is suitable for mechanistic studies of complex multicomponent analyses involving membrane-bound systems.
A free-standing high-output power density polymeric thermoelectric (TE) device is realized based on a highly conductive (approximate to 2500 S cm(-1)) structure-ordered poly(3,4-ethylenedioxythiophene):polystyrene sulfonate film (denoted as FS-PEDOT:PSS) with a Seebeck coefficient of 20.6 mu V K-1, an in-plane thermal conductivity of 0.64 W m(-1) K-1, and a peak power factor of 107 mu W K-2 m(-1) at room temperature. Under a small temperature gradient of 29 K, the TE device demonstrates a maximum output power density of 99 +/- 18.7 mu W cm(-2), which is the highest value achieved in pristine PEDOT:PSS based TE devices. In addition, a fivefold output power is demonstrated by series connecting five devices into a flexible thermoelectric module. The simplicity of assembling the films into flexible thermoelectric modules, the low out-of-plane thermal conductivity of 0.27 W m(-1) K-1, and free-standing feature indicates the potential to integrate the FS-PEDOT:PSS TE modules with textiles to power wearable electronics by harvesting human bodys heat. In addition to the high power factor, the high thermal stability of the FS-PEDOT:PSS films up to 250 degrees C is confirmed by in situ temperature-dependent X-ray diffraction and grazing incident wide angle X-ray scattering, which makes the FS-PEDOT:PSS films promising candidates for thermoelectric applications.
Some of the ongoing studies at our laboratory of gas-sensitive field-effect devices with catalytic metal gates are reviewed. More particularly, we discuss the use of such devices in so-called electronic noses due to the possibility of changing the selectivity patterns of the devices by the choice of catalytic metal and operation temperature. Several examples of the application of electronic noses consisting of field-effect devices in combination with metal oxide-based sensors are given. Finally, a summary is given of some remaining scientific problems and studies related to the understanding and development of gas-sensitive field-effect devices.
Barnacle larvae (cyprids) explore surfaces to identify suitable settlement sites. This process is selective, and cyprids respond to numerous surface cues. To better understand the settlement process, it is desirable to simultaneously monitor both the surface exploration behavior and any close interactions with the surface. Stereoscopic 3D tracking of the cyprids provides quantitative access to surface exploration and pre-settlement rituals. Imaging surface plasmon resonance (SPR) reveals any interactions with the surfaces, such as surface inspection during bipedal walking and deposition of temporary adhesives. We report on a combination of both techniques to bring together information on swimming behavior in the vicinity of the interface and physical interactions of the cyprid with the surface. The technical requirements are described, and we applied the setup to cyprids of Balanus amphitrite. Initial data shows the applicability of the combined instrument to correlate exploration and touchdown events on surfaces with different chemical termination. (C) 2015 Published by Elsevier B.V.
Electrocatalysis for energy‐efficient chemical transformations is a central concept behind sustainable technologies. Numerous efforts focus on synthesizing hydrogen peroxide, a major industrial chemical and potential fuel, using simple and green methods. Electrochemical synthesis of peroxide is a promising route. Herein it is demonstrated that the conducting polymer poly(3,4‐ethylenedioxythiophene), PEDOT, is an efficient and selective heterogeneous catalyst for the direct reduction of oxygen to hydrogen peroxide. While many metallic catalysts are known to generate peroxide, they subsequently catalyze decomposition of peroxide to water. PEDOT electrodes can support continuous generation of high concentrations of peroxide with Faraday efficiency remaining close to 100%. The mechanisms of PEDOT‐catalyzed reduction of O2 to H2O2 using in situ spectroscopic techniques and theoretical calculations, which both corroborate the existence of a chemisorbed reactive intermediate on the polymer chains that kinetically favors the selective reduction reaction to H2O2, are explored. These results offer a viable method for peroxide electrosynthesis and open new possibilities for intrinsic catalytic properties of conducting polymers.
The conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) has shown promise as air electrode in renewable energy technologies like metal-air batteries and fuel cells. PEDOT is based on atomic elements of high abundance and is synthesized at low temperature from solution. The mechanism of oxygen reduction reaction (ORR) over chemically polymerized PEDOT: Cl still remains controversial with eventual role of transition metal impurities. However, regardless of the mechanistic route, we here demonstrate yet another key active role of PEDOT in the ORR mechanism. Our study demonstrates the decoupling of conductivity (intrinsic property) from electrocatalysis (as an extrinsic phenomenon) yielding the evidence of doping of the polymer by oxygen during ORR. Hence, the PEDOT electrode is electrochemically reduced (undoped) in the voltage range of ORR regime, but O-2 keeps it conducting; ensuring PEDOT to act as an electrode for the ORR. The interaction of oxygen with the polymer electrode is investigated with a battery of spectroscopic techniques.
The antifouling (AF) properties of oligo(lactose)-based self-assembled monolayers (SAMs), using four different proteins, zoospores of the green alga Ulva linza and cells of the diatom Navicula incerta, were investigated. The SAM-forming alkylthiols, which contained 1, 2 or 3 lactose units, showed significant variation in AF properties, with no differences in wettability. Non-specific adsorption of albumin and pepsin was low on all surfaces. Adsorption of lysozyme and fibrinogen decreased with increasing number of lactose units in the SAM, in agreement with the generally observed phenomenon that thicker hydrated layers provide higher barriers to protein adsorption. Settlement of spores of U. linza followed an opposite trend, being greater on the bulkier, more hydrated SAMs. These SAMs are more ordered for the larger saccharide units, and it is therefore hypothesized that the degree of order, and differences in crystallinity or stiffness between the surfaces, is an important parameter regulating spore settlement on these surfaces.
We show that it is possible to induce a defined secondary structure in de nova designed peptides upon electrostatic attachment to negatively charged lipid bilayer vesicles without partitioning of the peptides into the membrane, and that the secondary structure can be varied via small changes in the primary amino acid sequence of the peptides. The peptides have a random-coil conformation in solution, and results from far-UV circular dichroism spectroscopy demonstrate that the structure induced by the interaction with silica nanoparticles is solely alpha-helical and also strongly pH-dependent. The present study shows that negatively charged vesicles, to which the peptides are electrostatically adsorbed via cationic amino acid residues, induce either alpha-helices or beta-sheets and that the conformation is dependent on both lipid composition and variations in peptide primary structure. The pH-dependence of the vesicle-induced peptide secondary structure is weak, which correlates well with small differences in the vesicles electrophoretic mobility, and thus the surface charge, as the pH is varied.
Vapour phase polymerized (VPP) PEDOT obtained using triblock copolymer PEG-PPG-PEG: Fe(III) tosylate polymeric oxidative layers has shown record-high conductivity and unique thermoelectric properties. These properties are related to the molecular weight, morphology and doping of PEDOT. Here we show that in its unwashed condition, the PEDOT chain adopts a neutral benzenoid conformation. The polymer chain converts into the charged quinoid structure after the removal of oxidizers with solvent washing. X-ray diffraction results suggest that the dopant is also incorporated into the packed polymer after the washing process. The changes in the chain structure and doping lead to the characteristic polaron and bipolaron absorption in the 800 and 1200 nm range. We observed a large contraction of the film after washing that is likely due to these changes, along with the removal of excessive polymer: oxidizer trapped in the PEDOT matrix. The contraction of films can be completely suppressed by mechanical clamping. PEDOT films without contraction show both a higher conductivity and higher optical transparency.
Treating PEDOT:PSS (Clevios) with certain additives, such as ethylene glycol (EG), dimethyl sulfoxide (DMSO) and sorbitol, has been shown to increase the conductivity of this material from roughly 1 to nearly 1000 S/cm. Using a slow drying method, we show that the additive induced a separation between free PSS and reorganized PEDOT:PSS complexes in the highly conductive PEDOT:PSS films. Additives (DMSO, DEG, and PEG 400) were included in PEDOT:PSS aqueous dispersions at large volume fractions. The mixtures were slowly dried under room conditions. During drying, the evaporation of water resulted in an additive-rich solvent mixture from which the reorganized PEDOT:PSS complexes aggregated " into a dense film while free PSS remained in the solution. Upon complete drying, PSS formed a transparent rim film around the conducting PEDOT film. The chemical compositions of the two phases were studied using an infrared microscope. This removal of PSS resulted in more compact packing of PEDOT molecules, as confirmed by X-ray diffraction measurements. X-ray photoelectron spectroscopy and atomic force microscope measurements suggested the enrichment of PEDOT on the film surface after PSS separation. Through a simple drying process in an additive-containing dispersion, the conductivity of PEDOT films increased from 0.1 to 200-400 S/cm. Through this method, we confirmed the existence of two phases in additive-treated and highly conductive PEDOT:PSS films. The proper separation between PSS and PEDOT will be of relevance in designing strategies to process high-performance plastic electrodes.
Gregarious settlement in barnacle larvae (cyprids) is induced by a contact pheromone, the settlement-inducing protein complex (SIPC). The SIPC has been identified both in the cuticle of adult barnacles and in the temporary adhesive secretion (footprint) of cyprids. Besides acting as a settlement inducer, the presence of the SIPC in footprints points to its additional involvement in the adhesion process. SIPC adsorption behaviour was therefore investigated on a series of self-assembled monolayers (SAMs) by surface plasmon resonance at the pH of seawater (8.3). Fibrinogen and alpha(2)-macroglobulin (A2M) (blood complement protease inhibitors with which the SIPC shares 29% sequence homology) were used in the adsorption experiments as positive and negative standards, respectively. The mass uptake of the SIPC was comparable to that of fibrinogen, with adsorption observed even on the protein-resistant oligo(ethylene glycol) surface. Notably, on the positively charged SAM the SIPC showed a kinetic overshoot, indicating a metastable configuration causing the amount of adsorbed protein to temporarily exceed its equilibrium value. A2M adsorption was low or negligible on all SAMs tested, except for the positively charged surface, indicating that A2M adsorption is mainly driven by electrostatics. Evaluation of SIPC non-specific adsorption kinetics revealed that it adsorbed irreversibly and non-cooperatively on all surfaces tested.
Gibbs surface energy has long been considered to be an important parameter in the design of fouling-resistant surfaces for marine applications. Rigorous testing of the hypothesis that settlement is related to Gibbs surface energy however has never been accomplished, due mainly to practical limitations imposed by the necessary combination of surface engineering and biological evaluation methods. In this article, the effects of surface charge and Gibbs surface energy on the settlement of cyprids of an important fouling barnacle, Balanus amphitrite, were evaluated. Settlement assays were conducted on a range of self-assembled monolayers (SAMs) (CH(3)-, OH-, COOH-, N(CH(3))(3)(+)-, NH(2)-terminated), presented in gold-coated polystyrene well plates, varying in terms of their surface charge and Gibbs surface energy. Contrary to contemporary theory, settlement was not increased by high-energy surfaces, rather the opposite was found to be the case with cyprids settling in greater numbers on a low-energy CH(3)- SAM compared to a high-energy OH- SAM. Settlement was also greater on negatively-charged SAMs, compared to neutral and positively-charged SAMs. These findings are discussed in the context of data drawn from surfaces that varied in multiple characteristics simultaneously, as have been used previously for such experiments. The finding that surface charge, rather than total surface energy, may be responsible for surface selection by cyprids, will have significant implications for the design of future fouling-resistant materials.
The colonization of man made structures by marine or freshwater organisms or "biofouling" is a problem for maritime and aquaculture industries. Increasing restrictions on the use of toxic coatings that prevent biofouling, create a gap in the market that requires new approaches to produce novel nonbiocidal alternatives. This review details the systematic strategy adopted by an FP6 EU Integrated Project "AMBIO" to develop fundamental understanding of key surface properties that influence settlement and adhesion of fouling organisms. By this approach the project contributes to the understanding of fundamental phenomena involved in biofouling, and to the development of environmentally benign solutions by coating manufacturers within the consortium. (c) 2008 American Vacuum Society.
Macroporous polymer films with long-range uniformity and biotinyl-moiety selective recognition sites have been developed. A hierarchical molecular imprinting strategy afforded significant enhancements in quartz crystal microbalance (QCM) sensitivities towards biotinylated compounds.
Rational design and informed development of nontoxic antifouling coatings requires a thorough understanding of the interactions between surfaces and fouling species. With more complex antifouling materials, such as composites or zwitterionic polymers, there follows also a need for better characterization of the materials as such. To further the understanding of the antifouling properties of charge-balanced polymers, we explore the properties of layered polyelectrolytes and their interactions with charged surfaces. These polymers were prepared via self-initiated photografting and photopolymerization (SIPGP); on top of a uniform bottom layer of anionic poly(methacrylic acid) (PMAA), a cationic poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) thickness gradient was formed. Infrared microscopy and imaging spectroscopic ellipsometry were used to characterize chemical composition and swelling of the combined layer. Direct force measurements by colloidal probe atomic force microscopy were performed to investigate the forces between the polymer gradients and charged probes. The swelling of PMAA and PDMAEMA are very different, with steric and electrostatic forces varying in a nontrivial manner along the gradient. The gradients can be tuned to form a protein-resistant charge-neutral region, and we demonstrate that this region, where both electrostatic and steric forces are small, is highly compressed and the origin of the protein resistance of this region is most likely an effect of strong hydration of charged residues at the surface, rather than swelling or bulk hydration of the polymer. In the highly swollen regions far from charge-neutrality, steric forces dominate the interactions between the probe and the polymer. In these regions, the SIPGP polymer has qualitative similarities with brushes, but we were unable to quantitatively describe the polymer as a brush, supporting previous data suggesting that these polymers are cross-linked.
We report on the preparation and characterization of thin polyampholytic hydrogel gradient films permitting pH-controlled protein resistance via the regulation of surface charges. The hydrogel gradients are composed of cationic poly(2-aminoethyl methacrylate hydrochloride) (PAEMA), and anionic poly(2-carboxyethyl acrylate) (PCEA) layers, which are fabricated by self-initiated photografting and photopolymerization (SIPGP). Using a two-step UV exposure procedure, a polymer thickness gradient of one component is formed on top of a uniform layer of the oppositely charged polymer. The swelling of the gradient films in water and buffers at different pH were characterized by imaging spectroscopic ellipsometry. The surface charge distribution and steric interactions with the hydrogel gradients were recorded by direct force measurement with colloidal-probe atomic force microscopy. We demonstrate that formation of a charged polymer thickness gradient on top of a uniform layer of opposite charge can result in a region of charge-neutrality. This charge-neutral region is highly resistant to non-specific adsorption of proteins, and its location along the gradient can be controlled via the pH of the surrounding buffer. The pH-controlled protein adsorption and desorption was monitored in real-time by imaging surface plasmon resonance, while the corresponding redistribution of surface charge was confirmed by direct force measurements.
The effects of cathode modification by a conjugated polymer interlayer PFPA1 on the performance of reversed organic solar cells (substrate/cathode/active layer/transparent anode) based on different active material systems and different substrate electrodes are systematically investigated. A reduction of the work function irrespective of the substrate cathode used is observed upon the deposition of the PFPA1 interlayer, which is further related to an improved built-in electric field and open-circuit voltage. The amphiphilic character of the PFPA1 interlayer alters the surface energy of the substrate cathode, leading to the formation of a better active layer morphology aiding efficient exciton dissociation and photocurrent extraction in the modified solar cells. Hence, internal quantum efficiency is found to be significantly higher than that of their unmodified counterparts, while optically, the modified and unmodified solar cells are identical. Moreover, the deep highest occupied molecular orbital (HOMO) of the PFPA1 interlayer improves the selectivity for all investigated substrate cathodes, thus enhancing the fill factor.
In organic bulk-heterojunction solar cells, energy losses at the active layer/electrode interface are often observed. Modification of these interfaces with organic interlayers optimizes charge carrier injection and extraction and thus improves device performance. In this work, the effects of cathode modification by a conjugated polymer interlayer PFPA1 on the performance of reversed organic solar cells (substrate/cathode/active layer/transparent anode) based on different active material systems and different substrate electrodes are systematically investigated. A reduction of the work function irrespective of the substrate cathode used is observed upon the deposition of the PFPA1 interlayer; further related to an improved built-in electric field and open-circuit voltage. The amphiphilic character of the PFPA1 interlayer alters the surface energy of the substrate cathode, leading to the formation of a better active layer morphology aiding efficient exciton dissociation and photocurrent extraction in the modified solar cells. Hence, internal quantum efficiency is found significantly higher than that of their unmodified counterparts, while optically, the modified and unmodified solar cells are identical. Moreover, the deep HOMO of the PFPA1 interlayer improves the selectivity for all investigated substrate cathodes, thus enhancing the fill factor. We demonstrate a possibility of improving photovoltaic performance of reversed solar cells via a simple and universal interface modification and provide the basic guidelines for development and characterization of interface materials for organic solar cells in general.
Adhesive proteins of barnacle cement have potential as environmentally friendly adhesives owing to their ability to adhere to various substrates in aqueous environments. By understanding the taxonomic breath of barnacles with different lifestyles, we may uncover commonalities in adhesives produced by these specialized organisms. The 19 kDa cement protein (cp19k) of the stalked barnacle Pollicipes pollicipes was expressed in Escherichia coli BL21 to investigate its adhesive properties. Initial expression of hexahistidine-tagged protein (rPpolcp19k-his) yielded low levels of insoluble protein. Co-overproduction of E. coli molecular chaperones GroEL-GroES and trigger factor (TF) increased soluble protein yields, although TF co-purified with the target protein (TF-rPpolcp19k-his). Surface coat analysis revealed high levels of adsorption of the TF-rPpolcp19k-his complex and of purified E. coli TF on both hydrophobic and hydrophilic surfaces, while low levels of adsorption were observed for rPpolcp19k-his. Tag-free rPpolcp19k protein also exhibited low adsorption compared to fibrinogen and Cell-Tak controls on hydrophobic, neutral hydrophilic and charged self-assembled monolayers under surface plasmon resonance assay conditions designed to mimic the barnacle cement gland or seawater. Because rPpolcp19k protein displays low adhesive capability, this protein is suggested to confer the ability to self-assemble into a plaque within the barnacle cement complex. This article is part of the theme issue Transdisciplinary approaches to the study of adhesion and adhesives in biological systems.
PEDOT-Tos is one of the conducting polymers that displays the most promising thermoelectric properties. Until now, it has been utterly difficult to control all the synthesis parameters and the morphology governing the thermoelectric properties. To improve our understanding of this material, we study the variation in the thermoelectric properties by a simple acido-basic treatment. The emphasis of this study is to elucidate the chemical changes induced by acid (HCl) or base (NaOH) treatment in PEDOT-Tos thin films using various spectroscopic and structural techniques. We could identify changes in the nanoscale morphology due to anion exchange between tosylate and Cl- or OH-. But, we identified that changing the pH leads to a tuning of the oxidation level of the polymer, which can explain the changes in thermoelectric properties. Hence, a simple acid-base treatment allows finding the optimum for the power factor in PEDOT-Tos thin films.
Interaction of zoospores of Ulva linza with cationic, arginine-rich oligopeptide self-assembled monolayers (SAMs) is characterized by rapid settlement. Some spores settle (ie permanently attach) in a normal manner involving the secretion of a permanent adhesive, retraction of the flagella and cell wall formation, whilst others undergo pseudosettlement whereby motile spores are trapped (attached) on the SAM surface without undergoing the normal metamorphosis into a settled spore. Holographic microscopy was used to record videos of swimming zoospores in the vicinity of surfaces with different cationic oligopeptide concentrations to provide time-resolved insights into processes associated with attachment of spores. The data reveal that spore attachment rate increases with increasing cationic peptide content. Accordingly, the decrease in swimming activity in the volume of seawater above the surface accelerated with increasing surface charge. Three-dimensional trajectories of individual swimming spores showed a hit and stick motion pattern, exclusively observed for the arginine-rich peptide SAMs, whereby spores were immediately trapped upon contact with the surface.
Lysosomes are acidic organelles essential for degradation, signalling and cell homoeostasis. In addition, they play a key role in cell death. Permeabilization of the lysosomal membrane and release of hydrolytic enzymes to the cytosol accompanies apoptosis signalling in several systems. The regulatory mechanism of lysosomal stability is, however, poorly understood. Lipophilic or amphiphilic compounds with a basic moiety will become protonated and trapped within lysosomes, and such lysosomotropic behaviour is also found in many pharmacological drugs. The natural sphingolipid sphingosine exhibits lysosomotropic detergent ability and is an endogenous candidate for controlling lysosomal membrane permeabilization. The lysosomotropic properties of certain detergents might be of use in lysosome-targeting anticancer drugs and drug delivery system in the future. The present review summarizes the current knowledge on the targeting and permeabilizing properties of lysosomotropic detergents from a cellular and physicochemical perspective.
Lysosomotropic detergents (LDs) selectively rupture lysosomal membranes through mechanisms that have yet to be characterized. A consensus view, currently, holds that LDs, which are weakly basic, diffuse across cellular membranes as monomers in an uncharged state, and via protonation in the acidic lysosomal compartment, they become trapped, accumulate, and subsequently solubilize the membrane and induce lysosomal membrane permeabilization. Here we demonstrate that the lysosomotropic detergent O-methyl-serine dodecylamide hydrochloride (MSDH) spontaneously assembles into vesicles at, and above, cytosolic pH, and that the vesicles disassemble as the pH reaches 6.4 or lower. The aggregation commences at concentrations below the range of those used in cell studies. Assembly and disassembly of the vesicles was studied via dynamic light scattering, zeta potential measurements, cryo-TEM, and fluorescence correlation spectroscopy and was found to be reversible via control of the pH. Aggregation of MSDH into closed vesicles under cytosolic conditions is at variance with the commonly held view of LD behavior, and we propose that endocytotic pathways should be considered as possible routes of LD entry into lysosomes. We further demonstrate that MSDH vesicles can be loaded with fluorophores via a solution transition from low to high pH, for subsequent release when the pH is lowered again. The ability to encapsulate molecular cargo into MSDH vesicles together with its ability to disaggregate at low pH and to permeabilize the lysosomal membrane presents an intriguing possibility to use MSDH as a delivery system.


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2016 Kastle Off-piste shootout!
Posted by Scott Gray on
Kastle Off-piste Shootout: FX95/FX95HP/BMX105/BMX105HP
As you likely know, Kastle overhauled their entire lineup of off-piste skis this past year. Gone is the older BMX lineup, with great snowfeel but some turn radii that were a bit much for some skiers. The FX lineup has also been overhauled for 2016: the FX has moved away from "MX-lite" to a much more off-piste based design. For 2016, Kastle is building basically the same "last" of ski in several widths: the FX and BMX series are almost identical skis; compared side by side, they have the same layups, close to the same rocker profiles. The difference is mainly in the graphic: the FX being the Chris Davenport "ski mountaineering" line and the BMX being the "big mountain" lineup. The other main distinction is the HP and the non-HP versions of each model: HP has 2 sheets of metal, the non-HP does not have metal. The non-metal version of this ski basically mirrors the layup of the "old" BMX lineup (BMX98/108/118/128). Kastle therefore has one of the most complete "off-piste but not super wide" lineups around, in the FX85, FX85HP, FX95, FX95HP, BMX105, BMX105HP. This is a massive range of skis that will cover any condition, skill level, and skier weight.
Tested today are the FX95HP/BMX105/BMX105HP
Conditions: see video attached: 16" of fresh snow in the previous 48 hours, quite heavy, lots of wind-loading, heavy skier traffic from MLK weekend, and therefore heavy set up crud and small to medium sized bumps forming. Flat light conditions as well.
Skier info: see video attached. 5 foot 9, 155lbs, ski 15-50 days a year. This was my 2nd day on snow this season, so skiing a bit slower than normal due to conditions and lack of fitness and timing! 38 years old
Reviews and comparisons:
Kastle FX95HP: this is the "flagship" model for Kastle for 2016, as it is the most commonly sold width. 95mm underfoot is good for just about any condition; the tip and tail rocker is enough to get out of the way upon turn entry and exit, yet it doesn't feel disconnected from the ski as some rockered skis can. The flex on this ski is dialed; very balanced tip to tail: no spots in the flex pattern that don't seem to fit the rest of the ski. The tip is stiff enough to hold up in chop, but supple enough to not to "push back" in bumps and set-up snow piles. The flex, IMO, couldn't be better. Getting exactly the correct tip flex in a ski is an elusive skill: we all know of wider skis that have aggressive tips that seem to rail around on hardpack groomers. Once off-piste however, they seem to be constantly pushing the skier into the backseat, making driving the tip a real chore; almost asking the skier to revert to skidding and other poor defensive techniques.
The first thing I noticed about the FX95HP is that it tracks unlike no other ski I have been on in a long time: snow hugging, but not a damp noodle. It has a substantial amount of metal, but is anything but
"clangy" in the way some skis seem to ricochet off any sort of crud pile. The FX95HP will track exceptionally well, provided you use some ankle flexion to help absorb terrain. Tipping to turn isn't quite enough with this ski: it likes active feet, even just a bit. I found the best way to navigate the cruddy bumps on this ski was to use a combo of techniques: the aggressive tipping of the new inside ski; down-unweighting at the end of the turn, and a foot-pullback move. This really allowed the ski to go flat and to engage the rocker early in the turn, pushing it down and getting the tip working fully. Some skis with less rocker, such as the Monster series, don't require that pull back move as much; tipping will suffice. But on a ski with rocker, tipping won't quite engage the front of the tip in the same manner: pulling the feet back in conjunction with the "little-toe edge tipping" move is more effective.
The FX95HP, in the junky crud, stuck to the terrain, was forgiving, and had a very nice sweet spot. It is a considerably quick ski, but not as quick as the non-metal BMX105. Stability doesn't get any better, although the 181cm will ski a bit "short". Compare it to a 177cm traditionally cambered ski: not in terms of stability; as the 181cm has as much beef as any skier will want. Rather, it doesn't have the "wheelbase" of a ski that is more than 176/177cm; the FX95HP is quite nimble but not overly grounded in the 181cm reference length. It's a great length for me, although for soft snow, I would gladly take this in a 184cm. Tracking is nearly perfect: in comparison to some stiffer all-mountain skis I have tried recently, it is down right silly in terms of how easy this ski is to get on edge. Another amazing feature of the FX/BMX lineup is that no one turn shape is preferred: if you go directly to a high edge angle early in the turn, it works with you. Like to let the ski run flat and slowly tip and edge? It isn't aggressive to find that new edge, unlike a lot of skis out there. It lets the skier decide the turn shape and style. The HP is also as good as anything in the market for that drift to edge turn, the one where the skier sets up the turn, begins to tip on to edge, and then counters the correct amount to load the ski before releasing. The "impact turn" as some would call it; this is the FX95's bread and butter.
In the mixed conditions I was utilizing the FX95HP, I couldn't have asked for more. Calm, controlled, smooth, easy, powerful; this ski can almost read your mind. I did venture out to a soft groomer, and the HP was decent. I wouldn't call it a carver, but it held up OK, with lots of energy, if you are willing to really get a big edge angle. At lower edge angles, it won't do much on groomers, and wants to drift. The tip has to be fully engaged to get the most out of it. The tail can pack a punch when loaded properly, no doubt. Still, this is primarily an off-piste ski. If you roam groomers for the most part, I would keep the MX series firmly in sight as the "holy grail" of a do-it-all with no compromise on hard snow ski.
BMX105: same ski as the FX95HP, but 10mm wider and no metal. First off, for those wondering about the width differences; in terms of edge engagement and quickness in those soft snow conditions, I couldn't tell which was which. Surely hard snow would lean more toward the 95, but this 105 was very, very quick indeed. Adding to the "narrow" feel was the light weight of the tip, and the ski in general: it turns in a hurry, and has very likely the "narrowest" feel of any wider ski I have ever tried. I would classify it as more of a "wider all-mountain" ski rather than a mainly new snow ski or a powder ski. I also compared it to a Fischer Ranger 108 the same day: the Ranger undoubtedly had the edge in tip float, but the BMX105 handled variable resort conditions in a superior manner. Look for a review shootout of of those skis soon.
The BMX105 was supremely capable: in terms of stability vs the 95HP, it lost maybe 5% of it's top end stability. Quickness was amplified by the light weight of the ski. It absorbed terrain even better than the HP; feeling like an upgraded BMX98. Very damp, just leveled undulating terrain and floated right over bumps. Quick onto edge, super precise once there, and will complete any turn shape you ask of it, with no predisposition to a certain turn shape or release style. The true definition of a hero ski. At my weight, not having metal in the ski was not a detriment. I wouldn't mind the extra stability, but by no means was I out-skiing the non-metal version of the BMX. Bigger skiers will want the HP metal; guys and gals near my weight have a decision to make. Trade off a bit of stability for extra quickness and ease of use, a larger sweet spot, and marginally better terrain damping? Or get the HP metal version and gain a bit of crud-crushing power and a stiffer, more snappy tail? Personally, I could go either way. In the video I linked, that terrain is best suited at my weight to a non-HP version. Above tree line, where I can really open things up, I would go HP all the way. Also, I do believe a skier will adapt to either one, and it would be impossible to make the "wrong" choice.
Kastle BMX105HP 181cm: same ski as the BMX105, but with 2 sheets of metal. Everything I said about the above 2 skis regarding turn shape suitability can also be said here; unlike some commenters, I don't prefer to hear myself talk endlessly, so please reference those notes. I did find the HP to have more top end, but also want to be opened up a bit more at my weight. It was just a touch less friendly in steep bumps; I had to ski cleaner, and engage the tip more aggressively. Definitely a ski that will strain at the leash just a bit. As smooth and terrain-leveling as any ski made however: it has more sweet spot than any ski in this performance category. If you find yourself looking for a ski that can handle tight terrain when asked, but also has the ability to magically transform a wide-open 35-degree crud field to groomer status and skiing speed, this is your model. If this were a car, it would be a BMW X6M: an M engine and M6 suspension+subframe, but with all-terrain ability and pure velvet glove luxury. Making a ski that is relatively easy to use isn't that hard: making a ski with a top end that would please any big-mountain freeride pro isn't too tough either. Marrying those 2 attributes into a friendly package that can please elite skiers is a skill that very few ski companies can pull off.
Overall suitability of each ski: this is a tough one, and completely subjective. It depends on 1) the skier's size; 2) the skier's ability; 3) the skier's typical terrain; 4) the skier's typical skiing speed. Starting off, if you ski really tight spaces and are a lightweight, look first at the non-HP models. If you are lighter, skilled, and skiing all turns fast, you could choose either. Looking for maximum top end and big turn ability? That calls for the HP. Bigger person that isn't skiing hobbit-sized woods all day? HP. Bumps? Non-HP is slightly better, but both are good. Less skilled big guy? I would look at the non-HP, you won't overpower it. Live for wide-open terrain at moderate speeds? It's a wash, the HP will track a bit better, the non-HP has the school-bus sized sweet spot.
There are enough nuances between these models to keep even the most passionate gear-junkie occupied for months, testing the various skis. I will follow up when I get more time on then. But suffice to say that Kastle has truly hit a home run with the FX and BMX, and now an off-piste selection to rival the MX. The MX, for what it's worth, is considered by many to be the best frontside and mixed-condition ski line ever made.

subset: commoncrawl


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The first time that we even considered writing a review for this software package we thought, "Nuh. This is one of them thangs thet makes pitcher's much so much that it gits ya sick to look at it!" We grimaced.
But then, we looked closer at software capabilities. We read something about jquery and CSS. We were overwhelmed and dissatisfied, mostly by/with our rudimentary coding skills.
Then, we did the smart thing and actually read all that we could about the software. We looked for images that had been created with it and didn't find anything. We realized that we wanted to learn it, review it and create images for those behind us who are as curious as we were.
We knew what we wanted to do. Yet, it was not possible, at our skill level. We watched the videos.
And over.
And over.
We perused the forums and decided that the people posting in those forums were pretty smart and that we might need another human to sit beside us and talk us through it. This is how we learned how to function in Photoshop. Nine years later and there is still so much more to learn.
We decided that there are not enough hours in the day (or night) of a busy product reviewer to re-learn Photoshop. We're motivated. The slide shows that you can create are far superior to what you get in Google docs. The animations are outstanding. However, even the simplest of animated graphics are out of reach.
For now.
Mint Mobile Phone
Save on wireless service, and when you activate your plan you'll a get $15 renewal credit and I'll get a $15 renewal credit. Yeaah - US! Click Here


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HEWLETT-PACKARD MODEL 1090 (Series - I and II) PARTS ONLY FOR SALE
UPDATE: NEW ORDERING TERMS With Credit Card Acceptance (USA Shipping/billing addresses only)
ORDERING INSTRUCTIONS and TERMS: To purchase one of these special items, please follow the steps listed below:
(1) Please send us an email indicating the exact item(s) you wish to purchase. Include your full name, company name, shipment street address, telephone number, Federal Tax ID number (if known), the item number(s), method of pre-payment and which website URL you saw it listed.
(2) By default, we ship all items using UPS ground, FedEx ground or USPS Priority Mail (least expensive method) with tracking numbers provided. If you have a shipping preference, then please let us know and we will quote it. *These items are available for shipment to addresses within the United States of America ONLY.
(3) In order to offer such low prices, we require that you pre-pay up front. Please indicate how you will make payment in your email. We accept business checks, bank wires and Credit Card payments made through PayPal (payments from PayPal USA "Verified" accounts shipping to their USA PayPal account street address ONLY. No exceptions!). If you wish to use PayPal, then please supply us with your PayPal specific email address too so we can send you an invoice.
Email all of the above requested information to us at "sales at HPLCTOOLS dot com" or <CLICK HERE>.
Upon receipt of your information, we will email you back an
invoice for the item (in Adobe PDF format). We will then place a temporary
"hold" on the item to allow you time to send full payment. Payment is due within
five business days time or the offer to sell will be void/expire. It is the
responsibility of the buyer to confirm that the item being purchased is appropriate for
their application or use. Note: Installation, training, qualification, verification and
warranties are not included in the sale price.
Unless otherwise stated, all items are sold "As-Is" with no warranty from Chiralizer Services or returns allowed. Please read the description carefully as we try to include detailed information for each item. Feel free to phone or email us with any specific questions before purchase.
Please Click on Thumbnail for a Larger Picture
Current Inventory
List of Gently USED HP 1090 (Series-II) PARTS;
Last Updated in May 2020 Please note that we have very few parts left and are no longer stocking them.
Hewlett-Packard 1090 / 1040 DAD (Series-I) Test Flow Cell
Item #79880-60006 : Fits Series-I HP1090 and 1040 DAD ONLY !!! . This "Dummy Cell" is used to test the lamp output and wavelength calibration. A must have item for this detector. Simply inserts into detector well. Price : $ 100 USD.
*BTW: We often stock fully tested Series-II flow cells as well so please inquire with your requirements.
HP 1090 HPLC Display and Keyboard Controller Board (DKC)
Item # 01090-66509 : From an HP 1090 II. For units with the system keyboard this is the board that communicates with the MCO board. Rev. 'B' with LUSI B (LIB #01090-66579) Rev. 'F' firmware from 1997 for use with the latest series-II AminoQuant systems. In excellent condition. Price : $ 300 USD.
HP 1090 HPLC Helium Inlet Valve Assembly
Item # 01090-67601 : From an HP 1090 II. In excellent condition. Price : $ 100 USD.
HP 1090 HPLC PV5 or DR5 Metering Channel Driver Board (MCD)
Item # 79835-66521 : From an HP 1090 Series-II system. MCD boards replaced the obsolete SCT and MDR boards into a single board. You need one board for each metering pump in your HPLC. In excellent condition. Price : $ 300 USD.
Agilent Analog Signal Cable: # 35900-60900
Item #35900-60900 : Brand NEW in factory package. Commonly used to connect an Integrator (3394/3395/3396) or 35900-series A/D box to a detector's output signal, this signal cable has a three pinned plug at one end and three spade lugs at the other. Agilent price is $104. Our Price : $ 80 USD.
HP Agilent HPIB Board, P/N 82350B
(For use with a PC and ChemStation Software)
Item # 82350B-66511 : This is an as-new, fully tested HPIB board which has been tested in a computer running ChemStation A.10.01 (works with ChemStation Revision A.09.03 or higher, including B.0#.##) for LC with an Agilent 1100 and HP 1090 HPLC system. The board has a PCI interface. Price : $ 150.
HP 1090 HPLC External Control Board (ECI)
Item # 01090-66526 : From an HP 1090 II. This is the latest revision of the board, Rev. 'D' and is backward compatible with older versions. This board provides four switchable contact closures or relay outputs which are useful in controlling valves and other accessories.The Series-I systems only had a four position relay board so this is a popular upgrade board. In excellent condition. Price : $ 150 USD.
HPIB Interface Cable 10833B
Item #HPIB-025 : We have one GPIB / HPIB interface cable in excellent condition. 2-meters in length. HP P/N 10833B. Price : $75 USD.
HP 1090 HPLC Remote Control Interface Board (RCI)
Item # 01090-66538 : From an HP 1090. Provides two remote signal DB9's and one two pin error contact closure signal connector. From a Series-II system. Shown on mounting plate, not included. In excellent condition. Price : $ 250 USD.
HP 1090 HPLC AutoInjector Cover Plate Set
Item # 01090-04137 (Left) & 79847-04104 (Right) : From an HP 1090 Series-II system. Two top plates with screws. These are often missing on units and here is a set in great condition with pozidrive screws ready for installation. Price : $ 150 USD.
HP 1090 HPLC IR Position Sensors Boards
Item #79846-66503: Swivel Arm Sensor. New IR Sensor on board. These usually require replacement after ten years due to age. List Price is $180. Our Price : $ 100 USD.
Item #79846-66504: A/I Valve Sensor. New IR Sensor on board. These usually require replacement after ten years due to age. List Price is $110. Our Price : $ 80 USD.
Hewlett-Packard 1040, 1090, 1050 HPLC Optical Slits (Set of 3)
Item #79883-80022: A 2nm Optical Slit ("Spring Style") for the 1040 (II), 1050 and 1090 (II) DAD and MWD detectors. Item #79883-80024 : A 4nm Optical Slit ("Spring Style") for the 1040 (II), 1050 and 1090 (II) DAD and MWD detectors. Item #79883-80028 : (not shown) An 8nm Optical Slit ("Spring Style") for the 1040 (II), 1050 and 1090 (II) DAD and MWD detectors. These interchangeable slits allow you to vary the amount of light that falls on the detector. Agilent/HP charges $200 each. All Three Slits : $ 150 USD.
HP 1090 HPLC Solvent Bottle Holder Assembly, Complete
Item # BottleHolder : From an HP 1090 Series-II system with three solvent pickup filters, three He gas spargers, Helium lines and all connectors. In excellent condition. Price : $ 250 USD.
Agilent CHEMSTATION FOR LC SOFTWARE (2D)
Item # ChemStation-A10 : Original Agilent Factory Disk and Registration License Label for ChemStation for HPLC, 2D Software. Revision A.10.01 (Aug 2003). This is one of the most stable and desireable versions of ChemStation software and can be used to control and gather data from many of the HP/Agilent 1050, 1090 and/or 1100-Series HPLC modules under Windows XP O/S. Price: $ 950 USD (2D) & $1,300 (2D + 3D Spectral Registration).
HP 1090 Mainframe to Diode Array Detector (DAD) Remote Control Cable, HP P/N 01040-60202)
Item # 01040-60202CLONE : If you have a 1090 Series-II HPLC with a 1040 Diode Array Detector (DAD) installed inside the mainframe, then you need the communication cable with edge card connectors to connect the two units together. This cable allows the two systems to share start, stop and other control signals through ChemStation. *An HPIB Cable is also needed and we sell these too. HP no longer makes these remote cables, but we offer a custom made clone cable which works just like the original one HP supplied. Price : $250 USD.
HP 1090 HPLC Injector-Sampler Driver Boards (ISD)
Item # 01090-66534 : From an HP 1090. Newer design, Rev 'B' boards from a Series-II system. One is used to control the Injector and the other the sampler. These are the boards with the five LEDs for monitoring the execution of the systems. Two boards in excellent condition. Price : $ 150 USD.
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Nocturnal Animals (2016) - 3/10. Total load of crap. Twice.
Appalled by the land whales? Surprised you didn't see it when it was in theaters. I dropped my rating to a 7/10 on second watch. If the film would have been solely about the West Texas portion and left out the L.A. soap opera it probably would have been the length of a tight Classic "B" Film Noir and better for it.
More like I was appalled by the idea of a Texan travelling across Texas at night with his family and not carrying any kind of weapon. And the fact that even the women don't have weapons! C'mon! The whole crime set-up is less about imagining real Texans in Texas and more about what a New Yorker would imagine about Texans and Texas. And the Michael Shannon character--totally ridiculous. The point where he asks Gyllenhaal if he's willing to NOT follow strict procedure--as if he'd been following procedures at any time prior to that! One of several moments where I had to guffaw.True, the story within the story was slightly better than the frame narrative (as you say). The soap opera stuff was right out of a 60s movie--I thought I was watching The Best of Everything or Valley of the Dolls at several points. But even the inner story wasn't much: a guy's family is murdered, and then the guy murders the murderers in revenge. The End. Uh, what? And this is supposed to be the transcendent reading experience that gets Amy And Her Beak off her ass and into the restaurant so that another kind of revenge--a very petty one--can be exacted? I gave up watching WWF repeats for this?
Agree if they were supposed to be Texans, I didn't catch that
Atomic Blonde - David LeitchAtomic good 8/10Charlotte forever ...
Charlotte Sometimes.
Jusqu'au dernier (1957) A good French Film Noir, Raymond Pellegrin (Fernand Bastia) is released from prison after a six month sentence. He goes into hiding at a traveling carnival where his sister Marcella is a fortune teller. The reason he is laying low is because he has double crossed his gang keeping a portion of the loot from a robbery just before he got pinched. Fernand gets a job being a carny barker, there he falls in love with Gina (Jeanne Moreau) but this gets another carney Quedchi jealous. Fredo Riccioni (Paul Meurisse the headmaster from Les Diaboliques), the boss of the gang that pulled the robbery job eventually manages to trace Fernand back to the carnival. There are only a pitiful handful of French Film Noir readily available here, there should be more.
You saw this on disc?


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The Ebola virus epidemic may well spread out of Africa. Dr Greg Martin takes a look at some of the variables that contribute to this risk and discusses some steps that should be taken.
This video is shared with permission from Dr Greg Martin's YouTube Channel.
Please follow the link below to find some procedures in handling of specimens from cases of suspected viral haemorrhagic fevers, including Ebola virus.
The African Society of Laboratory Medicine has compiled a comprehensive variety of resources related to Ebola for quick reference, including latest outbreak facts and news, specimen handling guidelines, diagnostic information, infection control manuals, communication tools, etc.
PLOS has compiled a collection of PLOS resources on Ebola, stressing the urgent need for research into all aspect of this Ebola outbreak - https://flipboard.com/section/plos-ebola-collection-bRVgYj -


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MWC 15 Special
expected, GIGA-BYTE Communications is
expanding its business to Europe and has officially announced the launch of
its GSmart t600 Windows Mobile Professional smartphone in France from mid-March
2008, along with its announcement of the partnership with the French MVNO - Neuf
When GIGA-BYTE Communications unveiled the GSmart t600, the World's first DVB-T
roaming Digital TV PDA phone
on last year's Mobile World Congress, it has marked its strong position in
this niche market, and with its success in the markets that it has entered,
GSmart is now ready to catch the attention of the French market.
GSmart t600 is the world's first digital TV PDA phone that supports DVB-T
roaming; it displays digital TV programs and images of the finest quality
through its 2.6", 260k-pixel VGA screen - a standard unseen in PDA phones. From
Internet browsing to photo slideshow, making the TV watching experience on
GSmart t600 a pleasure to the mind and eye. Reflecting the distinctive look of
porcelain with its semi-opaque front piece, GSmart t600 introduces a
never-to-be-seen lightness and pureness to the PDA phone world, displaying
confidence and freedom in the essence of minimalism.
GSmart t600 runs on Windows Mobile 6 Professional, which offers many new
business and multimedia features such as Windows Live, Windows Update, HTML
supported E-Mail and much more. Data processing and management is more efficient
than ever with the USB 2.0 enabled connectivity, 256 MB built-in memory, 520 MHz
CPU and accelerator. Apart from the 4 hour talk time, users can watch digital TV
for 2 consecutive hours. The built-in Spb Backup software backups and restores
important data, ensuring that users' valuable data is always secured.
More than just a phone with digital TV, GSmart t600 is designed to let
on-the-move users "work smart, play hard". Users can save their favorite
multimedia files on microSD card and listen to music, watch video, and browse
photos anytime, anywhere; or capture memorable moments using the 2 megapixel
cameras with auto focus and video recording functions. Unique phone applications
like phone recording, blacklist, and background sound effects provided only by
GSmart, are designed to ensure that users can make calls in the most efficient
Neuf Cegetel is the first alternative operator in France that has long harvested
in the communications industry and beyond, it has established an image of
innovation and out of tradition. The wide range of product lines such as mobile
phone, internet, and Neuf TV etc. have shown the capabilities of Neuf as a
strong communications and entertainment service provider. Sharing the similar
corporate values of innovation, GSmart and Neuf are looking forward to their
prosperous partnership. GSmart t600 will join the TWIN family as the latest
device in a series of mobile phones that support both GSM and also WiFi services
(internet, VoIP, IPTV). GSmart t600 will be into the French market the unique
mobile handset with DTT (Digital Terrestrial TV) feature. Under the partnership,
GSmart t600 will be available as a bundle Neuf's service plan, under the
commercial name of TWIN TNT.
Prices weren't announced today but a review will finally follow soon.
UPDATE: Depending on the tariff, the Twint TNT (aka GSmart t600) is
now available from Neuf Mobile for 89.00 Euro up to 209 Euro.
Cheers ~ Arne
Article Source
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Buy, sell, or hold
The answer is provided below in the annual Hoop Thoughts Stock Report (HTSR). Once again, the idea of this exercise is to project where a team is headed relative to its current position. That position is defined by its record, its ranking and that amorphous, subjectively defined animal we call "buzz."
The operative word here is relative. I'm more concerned with where teams are headed than where they are. So just because I rate Team A a Sell and Team B a Buy, that does not necessarily mean I think Team B is better than Team A. You dig?
I selected a HTSR-record 30 teams for this year's ratings. I wanted a healthy helping outside the Top 25, so my apologies if your favorite team wasn't included. Also, as promised, I'm going to start to include my AP ballot every week in this space. Feel free to have at me.
So without further ado, grab your wallets, Hoop Thinkers, and get ready to do some trading:
Arizona: SELL
I really, really want to like this Wildcats team, but they keep letting me down. I know they're playing without Jerryd Bayless right now, but that's no excuse for not showing up defensively at home against Oregon on Saturday. I like that Jordan Hill gives them an inside weapon they haven't had in a while, but unless this team adopts a tougher identity, it will continue to disappoint in the rough-and-tumble Pac-10.
Arizona State: BUY
You better scoop this one up quick before word gets out that the Sun Devils are legit. Between the Princeton offense and the zone defense, they play an unconventional style that is throwing people off. Everybody wrote them off when they got blitzed by Illinois in the opener, but since then they've trounced a good Xavier team at home and beat Oregon at home last Thursday (which Arizona couldn't do). Freshman guard James Harden, who leads the team in scoring at 17.6 per game, has certainly lived up to his billing.
Duke: SELL
The Blue Devils have a great Plan A: Spread the floor, drive to the basket, make threes. When that's working, they can beat anyone. But what happens if the threes aren't falling and you have to go to Plan B -- and you don't have a serviceable big man? My sense is that Duke's Plan B is to hope Plan A works.
Florida: SELL
The Gators only have two losses, and though everyone understood this would be a rebuilding year, I still get the sense people are anticipating a late surge from this young team. In a word: nagahappen. The Gators have a hard time generating offense off of their defense, and Marreese Speights has shown he is not quite ready to carry a team on his back.
Georgetown: BUY
The Hoyas were unable to impose their style at Memphis, but this is still far-and-away the class of the Big East. What's amazing about the Hoyas is they have arguably the best center in the country in Roy Hibbert, yet they're not overly dependent on him. I can't imagine a better fit for JT3's offense than freshman guard Austin Freeman, a big, strong athlete who can score inside and out.
Gonzaga: HOLD
Yes, the Zags have some good players and played a tough nonconference schedule, but the reality is, their best win of the season was by three points over UConn in Boston. (Not quite a neutral site, but still not as tough as Gampel Pavilion.) It would be silly to Sell them since they're already out of the Top 25, but unless they're able to pull off a win at Memphis on Jan. 26, they might have to win the WCC tournament again to get to the NCAAs.
Indiana: BUY
Hoosiers are just outside the top 10 right now, but that will change in the next couple of weeks. Not only is Eric Gordon the front-runner for Big Ten player of the year as a freshman, but I think he should be the No. 1 pick in the NBA draft. The Hoosiers also have plenty room for growth. Look for freshman Jordan Crawford and juco transfer Jamarcus Ellis to steadily improve the next two months.
Kansas: BUY
No need to overthink this one. The Jayhawks have more depth and talent than any team in America, and I love the way Darnell Jackson is playing down low. Plus, the Big 12 is just so-so and they only have to play Texas once.
Kansas State: SELL
I realize the Wildcats have a 9-4 record and are unranked, but I'd guess there are still some people out there who are thinking, "Well, they have Michael Beasley, so they're probably going to the tournament." No, they're not. You still need good guard play in college basketball, and with David Hoskins still not recovered from knee surgery, it looks like Beasley's one season of college basketball will have to end in the NIT.
Kentucky: BUY
Talk about a basement bargain. Cats have nowhere to go but up (I think), and with Derrick Jasper and Jodie Meeks healthy again, you might as well take a flyer on 'em.
Louisville: BUY
This has got to be the easiest pick on the board. Remember, last year the Cardinals were 6-4 in the Big East in early February and looked to be headed to the NIT. Then they got healthy and ended up a No. 6 seed in the NCAA tourney. This time, they got healthy in January. If they stay that way -- and if Edgar Sosa can somehow finagle his way out of Rick Pitino's doghouse -- then another mad dash is in the offing.
Marquette: HOLD
The Golden Eagles are short of quality big men and their guards don't make threes. But few teams do a better job masking their weaknesses and playing to their strengths. I don't see Marquette making its way to the top tier nationally, but they're a solid top-three finisher in the Big East and almost never lose games they should win. (There's no shame in losing close at West Virginia.)
Memphis: BUY
I'm usually skeptical that a team can go undefeated (and frankly wouldn't recommend it), but the Tigers have already survived the hard part of their schedule without a blemish. Right now, I'd give them a 50-50 chance to go into the NCAA tournament without a loss.
Michigan State: HOLD
The Spartans have been mighty impressive the last month, largely because Raymar Morgan is looking like an All-Big Ten player. But it's hard to see them going higher than No. 6 in both polls. Getting to the Final Four is a realistic goal for this group, but I'd be very surprised if they won it all.
North Carolina: BUY
For a team to be undefeated and ranked No. 1 and still warrant a Buy, you'd have to believe it will do nothing short of win the NCAA championship. And I do.
N.C. State: SELL
The Wolfpack was already struggling with Farnold Degand as their point guard. Now that he's gone for the year, they're even more deficient at this most critical position. (His replacement, 6-foot freshman Javier Gonzalez, is not ready for prime time.) Too bad, because in freshman J.J. Hickson and junior Brandon Costner, the Wolfpack have as good a 1-2 punch up front as you'll see in the ACC. But they still need someone to get 'em the ball.
Oklahoma: BUY
We knew the Sooners had some heft up front (my goodness, that Blake Griffin is something else), but their recent surge has been sparked by surprisingly efficient guard play. The top three spots in the Big 12 are pretty much locked up, but I like this team's chances of rising to the top of the second tier.
Ole Miss: SELL
In the twisted logic of the Hoop Thoughts stock report, the Rebs' win over Clemson actually makes them more likely to be rated a Sell. They're 13-0, they're ranked 16th in the AP poll, and they're playing at Tennessee Wednesday night. Seems to me they've got nowhere to go but down.
Pittsburgh: SELL
You'll want to keep an eye on this one because there's still some talent here, but even though the Panthers put up a good fight at Villanova on Sunday before losing, the reality is they have lost two starters to injury, including the one guy they could least afford to lose in point guard Levance Fields. Not only is Ronald Ramon not a point guard, but if Ramon is running the offense, that means he isn't catching the ball on the wing. They're saying Fields might come back from his foot injury at the end of the season, but I doubt that will leave him enough time to take the Panthers deep into the NCAA tournament.
Oregon: SELL
The Ducks were close to being a Hold, but I figure they're as high as they're going to get after winning at Arizona. We knew coming into the year they'd have a hard time replacing Aaron Brooks, and boy have they ever. Not only has Tajuan Porter not made the transition to point guard, but he has turned in some truly horrendous shooting performances. (He's making 31.5 percent from behind the arc and has gone 2 for 18 the last three games).
Tennessee: BUY
This is a vote for the Vols as well as a vote against the SEC. There's no team in the country that is more relentless than Tennessee, and you've got to figure it's only a matter of time before Chris Lofton rediscovers his shooting touch. J.P. Prince, the midseason transfer from Arizona, has also made a much bigger impact than I anticipated.
Texas: HOLD
The Longhorns registered the two sexiest triumphs of the nonconference season when they beat Tennessee and UCLA. When they shot them up to No. 4 in the AP poll, that was the time to sell. Now that they've settled in at No. 12 after losses to Michigan State and Wisconsin, they're probably right where they should be.
The addition of 6-7 freshman Gary Johnson should help (he missed the first 13 games after being diagnosed with a heart ailment, and had 15 points and six rebounds in Saturday's win over St. Mary's). If Johnson continues to have an impact, you may want to scoop up this stock in time for the final stretch, because there is Final Four-caliber talent here on the perimeter.
Texas A&M: SELL
At 12-1 and ranked 11th in the AP poll, the Aggies are a pretty safe bet to finish no lower than third in the Big 12. But they played a pretty easy nonconference schedule, and the one tough road game they played (at Arizona), they lost. Despite that comfy slate, they have committed 19 more turnovers than their opponents and are converting just 59.3 percent from the foul line.
I still like this team, but I'm starting to wonder if the Bruins are ever going to shake the injury bug. Losing Michael Roll again is a tough setback, and I'm still waiting for Darren Collison to show his old explosiveness. Kevin Love's conditioning is also an ongoing concern.
USC: SELL The Trojans finally fell out of the rankings after losing at Cal and Stanford last week. What bothers me is that the problems they have now are the same ones they had in early November. O.J. Mayo fires shots without conscience but can't (or won't) set up his teammates. (There's no excuse for a guard to take 19 shots and not have a single assist, as Mayo did in the loss at Stanford.) Taj Gibson is one of the bigger disappointments in college basketball, and as a team the Trojans are ranked last in the Pac-10 in turnovers and assist-to-turnover ratio.
Vanderbilt: HOLD
Give the Commodores credit for being undefeated, but the reality is, their best win came at home last Saturday against UMass. Vandy's porous defense led my guy Luke Winn to list the Commodores as one of his "early warning" teams. They're ranked 112th nationally in defensive efficiency and are 11th in the SEC in both field goal defense and three-point defense. The main reason I don't list them as a Sell is because the SEC is so lame. See how they play next week at Kentucky and Tennessee and you'll have a better idea how good this team really is.
Washington State: BUY
If I could rate a team a BUY-plus, I'd do it for the Cougars. I can't remember a team generating less buzz while being ranked fourth in both polls. It's not always about who has the best future NBA players, folks.
West Virginia: HOLD
I might have recommended you Buy the Mountaineers, but they got some good buzz by knocking off Marquette on Sunday in Morgantown, so I'd just as soon leave them right where they are. You've got to give Bob Huggins credit for keeping the principles of John Beilein's offense intact while installing his own philosophies on defense. Beilein recruited these guys to play a certain way, and Huggins has artfully kept them playing to their strengths.
Wisconsin: HOLD
Yes, I may have underestimated this Badgers team, but we still need to take a wait-and-see approach with this bunch. They're ranked 21st, and you have to wonder how much higher they can climb. The win at Texas was mighty impressive (especially without Trevon Hughes), but I also got the feeling that was as well as Wisconsin could possibly play. Can they keep it up? Or will they undergo a reality check in Big Ten play?
Xavier: BUY
I am mystified why the Musketeers are only ranked 24th, but I am equally certain they won't be so for long. Part of the reason they're so undervalued is so many voters overreacted to the loss at Arizona State. Given how well the Sun Devils have been playing, that loss doesn't look so bad now. I also recognize the Musketeers have a thin bench and no sure-fire NBA players, but they have an exciting veteran point guard in Drew Lavender and can beat you from a variety of positions.
Drake: At 11-1 (2-0 Missouri Valley), Drake is the best team in the state of Iowa. I know, that isn't saying very much.
Stephen F. Austin: The Lumberjacks are 12-1, and that wins at Oklahoma looks even better now.
South Alabama: John Pelphrey left plenty of talent behind. The Jaguars have won eight in a row and only lost at Vanderbilt by three points.
Nebraska: Led by 6-11 senior center Aleks Maric (16.2 points, 8.4 rebounds, 61.2 percent fg), Huskers have a chance to make you a quick buck when they host Kansas on Saturday.
South Florida: Bulls have a budding star in 6-4 freshman Dominique Jones. They're so undervalued right now, even if they make it to the Big East tournament, they'll be a good investment.
Penn and Princeton: Where have you gone, Pete Carril and Bob Weinauer? The perennial Ivy giants are a combined 7-20.
LSU: Tigers have lost five of their last seven, and Tasmin Mitchell, their best player, is out for the season. If the SEC season is a disaster, you can expect to hear a lot of speculation about John Brady's job security.
Oregon State: Seems like the only certainty in the Pac-10 is that the Beavers will finish last and Jay John will not be back next season.
Michigan: People ask me if there are ever days when John Beilein is happy he took this job. My answer: the first and 15th of every month.