In monolayer graphene, substitutional doping during growth can be used to alter its electronic properties. We used scanning tunneling microscopy, Raman spectroscopy, x-ray spectroscopy, and first ...principles calculations to characterize individual nitrogen dopants in monolayer graphene grown on a copper substrate. Individual nitrogen atoms were incorporated as graphitic dopants, and a fraction of the extra electron on each nitrogen atom was delocalized into the graphene lattice. The electronic structure of nitrogen-doped graphene was strongly modified only within a few lattice spacings of the site of the nitrogen dopant. These findings show that chemical doping is a promising route to achieving high-quality graphene films with a large carrier concentration.
To aid understanding of the effect of antiviral treatment on population-level influenza transmission, we used a novel pharmacokinetic-viral kinetic transmission model to test the correlation between ...nasal viral load and infectiousness, and to evaluate the impact that timing of treatment with the antivirals oseltamivir or baloxavir has on influenza transmission. The model was run under three candidate profiles whereby infectiousness was assumed to be proportional to viral titer on a natural-scale, log-scale, or dose-response model. Viral kinetic profiles in the presence and absence of antiviral treatment were compared for each individual (N = 1000 simulated individuals); subsequently, viral transmission mitigation was calculated. The predicted transmission mitigation was greater with earlier administration of antiviral treatment, and with baloxavir versus oseltamivir. When treatment was initiated 12-24 hours post symptom onset, the predicted transmission mitigation was 39.9-56.4% for baloxavir and 26.6-38.3% for oseltamivir depending on the infectiousness profile. When treatment was initiated 36-48 hours post symptom onset, the predicted transmission mitigation decreased to 0.8-28.3% for baloxavir and 0.8-19.9% for oseltamivir. Model estimates were compared with clinical data from the BLOCKSTONE post-exposure prophylaxis study, which indicated the log-scale model for infectiousness best fit the observed data and that baloxavir affords greater reductions in secondary case rates compared with neuraminidase inhibitors. These findings suggest a role for baloxavir and oseltamivir in reducing influenza transmission when treatment is initiated within 48 hours of symptom onset in the index patient.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
3.
Ferromagnetic Ordering in Superatomic Solids Lee, Chul-Ho; Liu, Lian; Bejger, Christopher ...
Journal of the American Chemical Society,
12/2014, Letnik:
136, Številka:
48
Journal Article
Recenzirano
In order to realize significant benefits from the assembly of solid-state materials from molecular cluster superatomic building blocks, several criteria must be met. Reproducible syntheses must ...reliably produce macroscopic amounts of pure material; the cluster-assembled solids must show properties that are more than simply averages of those of the constituent subunits; and rational changes to the chemical structures of the subunits must result in predictable changes in the collective properties of the solid. In this report we show that we can meet these requirements. Using a combination of magnetometry and muon spin relaxation measurements, we demonstrate that crystallographically defined superatomic solids assembled from molecular nickel telluride clusters and fullerenes undergo a ferromagnetic phase transition at low temperatures. Moreover, we show that when we modify the constituent superatoms, the cooperative magnetic properties change in predictable ways.
Analysis of the spatial dependence of current-voltage characteristics obtained from scanning tunneling microscopy experiments indicates that the charge density wave (CDW) occurring in NbSe_{2} is ...subject to locally strong pinning by a non-negligible density of defects, but that on the length scales accessible in this experiment the material is in a "Bragg glass" phase where dislocations and antidislocations occur in bound pairs and free dislocations are not observed. An analysis based on a Landau theory is presented showing how a strong local modulation may produce only a weak long range effect on the CDW phase.
Early detection of influenza may improve responses against outbreaks. This study was part of a clinical study assessing the efficacy of a novel influenza vaccine, aiming to discover distinct, highly ...predictive patterns of pre-symptomatic illness based on changes in advanced physiological parameters using a novel wearable sensor. Participants were frequently monitored 24 h before and for nine days after the influenza challenge. Viral load was measured daily, and self-reported symptoms were collected twice a day. The Random Forest classifier model was used to classify the participants based on changes in the measured parameters. A total of 116 participants with ~3,400,000 data points were included. Changes in parameters were detected at an early stage of the disease, before the development of symptomatic illness. Heart rate, blood pressure, cardiac output, and systemic vascular resistance showed the greatest changes in the third post-exposure day, correlating with viral load. Applying the classifier model identified participants as flu-positive or negative with an accuracy of 0.81 ± 0.05 two days before major symptoms appeared. Cardiac index and diastolic blood pressure were the leading predicting factors when using data from the first and second day. This study suggests that frequent remote monitoring of advanced physiological parameters may provide early pre-symptomatic detection of flu.
Quantum‐chemical calculations predict the existence of two almost equal‐energy isomers of the FSO5 radical with either side‐on or end‐on bonding of O2 to FSO3 (see picture). The structure of this ...polyoxy radical isolated in solid noble‐gas matrices and formed by the reaction of FSO3 with molecular oxygen has now been revealed by IR and UV spectroscopic investigations.
Campylobacteriosis is one of the most common types of bacterial gastroenteritis affecting humans, and poultry is considered a major source of the causative organism, Campylobacter spp. Broilers may ...arrive contaminated at slaughterhouses, and transport crates could be considered a potential source of contamination. Thus, cleaning and disinfection procedures are crucial to avoid cross-contamination among flocks. Despite its public health importance in Latin American countries, virulence factors of Campylobacter jejuni remain poorly studied in this region. Thus, this study aimed to: 1) determine the occurrence of contaminated crates at a poultry slaughterhouse, 2) compare the contamination before and after the cleaning and disinfection procedures, and 3) detect virulence-associated genes in C. jejuni strains by PCR. Campylobacter spp. were recovered from 8 of the 10 flocks evaluated, and C. jejuni was detected as the main species. There was no significant difference in the Campylobacter detection or quantification between crates at the reception platform and crates after the cleaning/disinfection processes. However, crates after 24 h of natural drying, presented a significant (P < 0.05) lower amount of Campylobacter cells than before the cleaning and disinfection processes. A negative relationship (R2 = 0.210, P = 0.045) between environmental conditions and Campylobacter quantification was found for transport crates after 24 h of natural drying. There was no significant difference (P > 0.05) in the detection of two C. jejuni virulence genes, flaA (encode a major flagellin protein) and cadF (encode an adhesion and fibronectin-binding protein), among various stages of the cleaning and disinfection processes. Our results demonstrate the high contamination levels of Campylobacter strains in broiler flocks and the potential involvement of poultry transport crates in transmitting these bacteria. This study also suggests that ineffective cleaning and disinfection procedures can increase Campylobacter contamination and facilitate the spread of bacteria in poultry establishments.
PDF
