Transmission of Aerosolized Seasonal H1N1 Influenza A to Ferrets

Influenza virus is a major cause of morbidity and mortality worldwide, yet little quantitative understanding of transmission is available to guide evidence-based public health practice. Recent studies of influenza non-contact transmission between ferrets and guinea pigs have provided insights into the relative transmission efficiencies of pandemic and seasonal strains, but the infecting dose and subsequent contagion has not been quantified for most strains. In order to measure the aerosol infectious dose for 50% (aID50) of seronegative ferrets, seasonal influenza virus was nebulized into an exposure chamber with controlled airflow limiting inhalation to airborne particles less than 5 µm diameter. Airborne virus was collected by liquid impinger and Teflon filters during nebulization of varying doses of aerosolized virus. Since culturable virus was accurately captured on filters only up to 20 minutes, airborne viral RNA collected during 1-hour exposures was quantified by two assays, a high-throughput RT-PCR/mass spectrometry assay detecting 6 genome segments (Ibis T5000™ Biosensor system) and a standard real time RT-qPCR assay. Using the more sensitive T5000 assay, the aID50 for A/New Caledonia/20/99 (H1N1) was approximately 4 infectious virus particles under the exposure conditions used. Although seroconversion and sustained levels of viral RNA in upper airway secretions suggested established mucosal infection, viral cultures were almost always negative. Thus after inhalation, this seasonal H1N1 virus may replicate less efficiently than H3N2 virus after mucosal deposition and exhibit less contagion after aerosol exposure

Exhaled Aerosol Transmission of Pandemic and Seasonal H1N1 Influenza Viruses in the Ferret

Person-to-person transmission of influenza viruses occurs by contact (direct and fomites) and non-contact (droplet and small particle aerosol) routes, but the quantitative dynamics and relative contributions of these routes are incompletely understood. The transmissibility of influenza strains estimated from secondary attack rates in closed human populations is confounded by large variations in population susceptibilities. An experimental method to phenotype strains for transmissibility in an animal model could provide relative efficiencies of transmission. We developed an experimental method to detect exhaled viral aerosol transmission between unanesthetized infected and susceptible ferrets, measured aerosol particle size and number, and quantified the viral genomic RNA in the exhaled aerosol. During brief 3-hour exposures to exhaled viral aerosols in airflow-controlled chambers, three strains of pandemic 2009 H1N1 strains were frequently transmitted to susceptible ferrets. In contrast one seasonal H1N1 strain was not transmitted in spite of higher levels of viral RNA in the exhaled aerosol. Among three pandemic strains, the two strains causing weight loss and illness in the intranasally infected ‘donor’ ferrets were transmitted less efficiently from the donor than the strain causing no detectable illness, suggesting that the mucosal inflammatory response may attenuate viable exhaled virus. Although exhaled viral RNA remained constant, transmission efficiency diminished from day 1 to day 5 after donor infection. Thus, aerosol transmission between ferrets may be dependent on at least four characteristics of virus-host relationships including the level of exhaled virus, infectious particle size, mucosal inflammation, and viral replication efficiency in susceptible mucosa

Knowledge and opinions of dietetics and pharmacy students about sugar substitutes

Na świecie wzrasta liczba osób otyłych oraz z nadwagą, dlatego w ostatnim czasie rośnie również popularność substytutów cukru stosowanych do produkcji żywności niskoenergetycznej. Istnieje więc potrzeba monitorowania oraz limitowania substancji słodzących, przeprowadzania badań, które wykluczą szkodliwość tych środków i zapewnią konsumentom bezpieczną żywność. W celu oceny wiedzy i opinii studentów Farmacji oraz Dietetyki przeprowadzono badanie ankietowe z użyciem kwestionariusza. Większość ankietowanych obu analizowanych kierunków zna budowę chemiczną najbardziej popularnego substytutu cukru jakim jest aspartam. Dalej, respondenci nie potrafią interpretować oznaczeń, które wedle ustanowień prawnych powinny znajdować się na produktach zawierających w składzie polialkohole oraz aspartam. Zdaniem większości studentów Dietetyki dostęp do informacji na temat substytutów cukru jest niewystarczający, natomiast studenci Farmacji częściej wyrażali brak zainteresowania tematem. Studenci Dietetyki częściej deklarowali sprawdzanie etykiet produktów spożywczych i częściej deklarowali zakup produktu niezawierającego sztucznych substancji słodzących. Substancje słodzące są obecne zarówno w żywności jak i w produktach farmaceutycznych, dlatego ważne jest przekazywanie studentom ankietowanych kierunków wiarygodnych informacji na ten temat.The increasing number of obese and overweight people is the reason for the usage of sugar substitutes in low calorie food production. The monitoring of usage, limitation and research is necessary to ensure the safety of food for millions of people. The aim of the study was to access the students' opinions about sugar substitutes and their usage on the basis of a questionnaire study. The majority of respondents knew the chemical construction of aspartame. The students surveyed did not correctly interpret the labels which should be included on products containing polyalcohols and aspartame. In the opinion of the dietetics students, access to information about sugar substitutes is insufficient, while pharmacy students more often declared a lack of interest in the subject. Dietitians more often check labels on food products, and they usually do not buy products containing aspartame. Sweetening substances are present both in food and pharmaceutical products, and this is the reason why dietetic and pharmacy students should have reliable information on this subject

Dynamic behavior of copper under extreme loading rates

Metals subjected to extreme loading rates exhibit behavior that is characteristics of a thermodynamically open system characterized by exchanging energy due to dislocations traveling long distances with a nearly sonic velocity. The thermodynamic openness is rarely observed in solids; therefore the mean-field theories of nonlinear continuum dynamics often provide sufficient representation of the solid behavior. These theories describe the deformation and damage processes with the use of constitutive models. In addition, an equation of state (EOS) that couples high hydrostatic pressure and changes in mass density and temperature is formulated. Difficulties arise when a metal is subjected to extreme loading. Then, the material experiences a mesoscale excitation coupled with velocity fluctuations and a non-negligible entrapment of kinetic energy