RESUMEN
Asunto(s)
Esputo , Tuberculosis Pulmonar , Humanos , Esputo/microbiología , Estados Unidos , Tuberculosis Pulmonar/diagnóstico , Tuberculosis Pulmonar/epidemiología , Tuberculosis Pulmonar/microbiología , Adolescente , Masculino , Persona de Mediana Edad , Adulto , Adulto Joven , Femenino , Anciano , Niño , Preescolar , Lactante , Modelos Logísticos , Mycobacterium tuberculosis/aislamiento & purificaciónRESUMEN
Each year in the United States, an estimated 525 000 infections, 2900 hospitalizations, and 82 deaths are attributed to consumption of pork. We analyzed the epidemiology of outbreaks attributed to pork in the United States reported to the Centers for Disease Control and Prevention (CDC) 1998-2015. During that period, 288 outbreaks were attributed to pork, resulting in 6372 illnesses, 443 hospitalizations, and four deaths. The frequency of outbreaks attributed to pork decreased by 37% during this period, consistent with a decline in total foodborne outbreaks. However, outbreaks attributed to pork increased by 73% in 2015 (19 outbreaks) compared with the previous 3 years (average of 11 outbreaks per year), without a similar increase in total foodborne outbreaks. Most (>99%) of these outbreaks occurred among people exposed in the same state. The most frequent etiology shifted from Staphylococcus aureus toxin during 1998-2001 (19%) to Salmonella during 2012-2015 (46%). Outbreaks associated with ham decreased from eight outbreaks per year during 1998-2001, to one per year during 2012-2015 (P < 0·01). Additional efforts are necessary to reduce outbreaks and sporadic illnesses associated with pork products.
Asunto(s)
Brotes de Enfermedades , Microbiología de Alimentos , Enfermedades Transmitidas por los Alimentos/epidemiología , Carne Roja/microbiología , Animales , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/mortalidad , Incidencia , Sus scrofa , Estados Unidos/epidemiologíaRESUMEN
In a recent paper [C. E. Bertrand et al., J. Chem. Phys. 145, 014502 (2016)], we have shown that the collective dynamics of methanol shows a fast relaxation process related to the standard density-fluctuation heat mode and a slow non-Fickian mode originating from the hydrogen bonded molecular associates. Here we report on the length scale dependence of this slow relaxation process. Using quasielastic neutron scattering and molecular dynamics simulations, we show that the dynamics of the slow process is affected by the structuring of the associates, which is accessible through polarized neutron diffraction experiments. Using a series of partially deuterated samples, the dynamics of the associates is investigated and is found to have a similar time scale to the lifetime of hydrogen bonding in the system. Both the structural relaxation and the dynamics of the associates are thermally activated by the breaking of hydrogen bonding.
RESUMEN
Quasielastic neutron scattering measurements and molecular dynamics simulations were combined to investigate the collective dynamics of deuterated methanol, CD3OD. In the experimentally determined dynamic structure factor, a slow, non-Fickian mode was observed in addition to the standard density-fluctuation heat mode. The simulation results indicate that the slow dynamical process originates from the hydrogen bonding of methanol molecules. The qualitative behavior of this mode is similar to the previously observed α-relaxation in supercooled water [M. C. Bellissent-Funel et al., Phys. Rev. Lett. 85, 3644 (2000)] which also originates from the formation and dissolution of hydrogen-bonded associates (supramolecular clusters). In methanol, however, this mode is distinguishable well above the freezing transition. This finding indicates that an emergent slow mode is not unique to supercooled water, but may instead be a general feature of hydrogen-bonding liquids and associating molecular liquids.