{'fraction_non_alphanumeric': 0.03640776699029126, 'fraction_numerical': 0.023462783171521034, 'mean_word_length': 5.063725490196078, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Thermal inactivation of untreated and gamma-irradiated A2-Aichi-2-68 influenza virus.

Summary
The infectivity and the haemagglutinin activity of A2/Aichi/2/68 influenza virus were unchanged during a 2-year storage in allantoic fluid at -80 °C. Over the temperature range from -20 to + 37 °C, exponential slopes could be drawn by means of the regression analysis, the velocity constants showing very low values. Conversely, at + 56 °C inactivation took place in a two-component fashion, each following first-order kinetics. Haemagglutinin and neuraminidase activities were not impaired by exposure to [60Co]-γ-rays (3 × 106 rad), which completely removed infectious particles. The specific rate constants for inactivation of haemagglutinin and neuraminidase activities of untreated and irradiated virus were overlapping when samples were stored for 2 years in the frozen state (- 80 and - 20 °C), whereas a significantly increasing rate of inactivation was recorded for γ-irradiated samples following storage at temperature above 4 °C. Nevertheless, the energy of activation required for thermal inactivation was very low and the entropy of activation showed negative values for both the untreated and the irradiated virus preparations.