Thermal noise of highly reflective mirror coatings is a major limit to the sensitivity of many precision laser experiments with strict requirements such as low optical absorption. Here, we ...investigate amorphous silicon and silicon nitride as an alternative to the currently used combination of coating materials, silica, and tantala. We demonstrate an improvement by a factor of ≈55 with respect to the lowest so far reported optical absorption of amorphous silicon at near-infrared wavelengths. This reduction was achieved via a combination of heat treatment, final operation at low temperature, and a wavelength of 2 μm instead of the more commonly used 1550 nm. Our silicon-based coating offers a factor of 12 thermal noise reduction compared to the performance possible with silica and tantala at 20 K. In gravitational-wave detectors, a noise reduction by a factor of 12 corresponds to an increase in the average detection rate by three orders of magnitude (≈12^{3}).
Despite many recent efforts to predict and control emerging infectious disease threats to humans, we failed to anticipate the zoonotic viruses which led to pandemics in 2009 and 2020. The morbidity, ...mortality, and economic costs of these pandemics have been staggering. We desperately need a more targeted, cost-efficient, and sustainable strategy to detect and mitigate future zoonotic respiratory virus threats. Evidence suggests that the transition from an animal virus to a human pathogen is incremental and requires a considerable number of spillover events and considerable time before a pandemic variant emerges. This evolutionary view argues for the refocusing of public health resources on novel respiratory virus surveillance at human-animal interfaces in geographical hotspots for emerging infectious diseases. Where human-animal interface surveillance is not possible, a secondary high-yield, cost-efficient strategy is to conduct novel respiratory virus surveillance among pneumonia patients in these same hotspots. When novel pathogens are discovered, they must be quickly assessed for their human risk and, if indicated, mitigation strategies initiated. In this review, we discuss the most common respiratory virus threats, current efforts at early emerging pathogen detection, and propose and defend new molecular pathogen discovery strategies with the goal of preempting future pandemics.
Thermal noise arising from mechanical dissipation in oxide mirror coatings is an important limit to the sensitivity of future gravitational wave detectors, optical atomic clocks and other precision ...measurement systems. Here, we present measurements of the temperature dependence of the mechanical dissipation of an ion-beam sputtered silica film between 10 and 300 K. A dissipation peak was observed at 20 K and the low temperature dissipation was found to have significantly different characteristics than observed for bulk silica and silica films deposited by alternative techniques. These results are important for better understanding the underlying mechanisms of mechanical dissipation, and thus thermal noise, in the most commonly-used reflective coatings for precision measurements.
Understanding the local atomic order in amorphous thin film coatings and how it relates to macroscopic performance factors, such as mechanical loss, provides an important path towards enabling the ...accelerated discovery and development of improved coatings. High precision x-ray scattering measurements of thin films of amorphous zirconia-doped tantala (ZrO_{2}-Ta_{2}O_{5}) show systematic changes in intermediate range order (IRO) as a function of postdeposition heat treatment (annealing). Atomic modeling captures and explains these changes, and shows that the material has building blocks of metal-centered polyhedra and the effect of annealing is to alter the connections between the polyhedra. The observed changes in IRO are associated with a shift in the ratio of corner-sharing to edge-sharing polyhedra. These changes correlate with changes in mechanical loss upon annealing, and suggest that the mechanical loss can be reduced by developing a material with a designed ratio of corner-sharing to edge-sharing polyhedra.
Abstract
Background
Leptospirosis diagnoses have increased in Sarawak, Malaysia in recent years.
Methods
To better understand the burden of disease and associated risk factors, we evaluated 147 ...patients presenting with clinical leptospirosis to local hospitals in Sarawak, Malaysia for the presence of
Leptospira
and associated antibodies. Sera and urine specimens collected during the acute illness phase were assessed via a commercially available rapid diagnostic test (Leptorapide, Linnodee Ltd., Antrim, Northern Ireland), an ELISA IgM assay (
Leptospira
IgM ELISA, PanBio, Queensland, Australia) and a pan-
Leptospira
real-time PCR (qPCR) assay to estimate disease prevalence and diagnostic accuracy of each method. Microagglutination testing was performed on a subset of samples.
Results
Overall, 45 out of 147 patients (30.6%) showed evidence of leptospires through qPCR in either one or both sera (20 patients) or urine (33 patients), and an additional ten (6.8%) were considered positive through serological testing, for an overall prevalence of 37.4% within the study population. However, each diagnostic method individually yielded disparate prevalence estimates: rapid test 42.2% for sera and 30.5% for urine, ELISA 15.0% for sera, qPCR 13.8% for sera and 23.4% for urine. Molecular characterization of a subset of positive samples by conventional PCR identified the bacterial species as
Leptospira interrogans
in 4 specimens. A multivariate risk factor analysis for the outcome of leptospirosis identified having completed primary school (OR = 2.5; 95 CI% 1.0–6.4) and weekly clothes-washing in local rivers (OR = 10.6; 95 CI% 1.4–214.8) with increased likelihood of leptospirosis when compared with those who had not.
Conclusion
Overall, the data suggest a relatively high prevalence of leptospirosis in the study population. The low sensitivities of the rapid diagnostic test and ELISA assay against qPCR highlight a need for better screening tools.
Abstract
During April and May 2020, we studied 20 patients hospitalized with coronavirus disease 2019 (COVID-19), their hospital rooms (fomites and aerosols), and their close contacts for molecular ...and culture evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Among >400 samples, we found molecular evidence of virus in most sample types, especially the nasopharyngeal (NP), saliva, and fecal samples, but the prevalence of molecular positivity among fomites and aerosols was low. The agreement between NP swab and saliva positivity was high (89.5%; κ = 0.79). Two NP swabs collected from patients on days 1 and 7 post–symptom onset had evidence of infectious virus (2 passages over 14 days in Vero E6 cells). In summary, the low molecular prevalence and lack of viable SARS-CoV-2 virus in fomites and air samples implied low nosocomial risk of SARS-CoV-2 transmission through inanimate objects or aerosols.
In studying 20 hospitalized COVID-19 patients, we found the highest prevalence of severe acute respiratory syndrome coronavirus 2 RNA among patients’ nasopharyngeal and saliva samples (high correlation), but also RNA on fomites and in room air. However, only 2 nasopharyngeal swabs were culture positive.
Abstract
Human adenovirus type 4 (HAdV-E4) frequently causes epidemics among military and civilian populations. We conducted a systematic review of 144 peer-reviewed articles reporting HAdV-E4 ...infections, published during the years 1960–2020. More than 24 500 HAdV-E4 infections, including 27 associated deaths, were documented. HAdV-E4 infections were reported from all geographic regions of the world except Central America and the Caribbean. The number of publications reporting civilian infections tripled in the last decade, with a steady increase in reported civilian infections over time. Infections commonly caused respiratory and ocular disease. North America reported the most infections, followed by Asia and Europe. The majority of deaths were reported in the United States, followed by China and Singapore. Civilians seem to increasingly suffer HAdV-E4 disease, with recent epidemics among US college students. Public health officials should consider seeking emergency use authorization for the adenovirus vaccine such that it might be available to mitigate civilian epidemics.
As human adenovirus type 4 morbidity seems to be increasing among civilian populations, public health officials should consider seeking emergency use authorization for the current adenovirus vaccine (Teva Pharmaceuticals, USA) such that it could be used to mitigate civilian epidemics.
Circumstantial evidence indicates that aerosol transmission is a likely contributor to the current pandemic, 1‐3 yet research teams have had difficulty isolating live virus when using traditional ...aerosol sampling techniques. 4‐6 To our knowledge, thus far only two research teams have successfully cultured airborne SARS‐CoV‐2 outside of laboratory simulations, 7 with one team finding evidence of viral replication in the absence of cytopathic effect. 8,9 Despite the demonstrated challenges in capturing suspended live virus, respiratory transmission is now thought of as the primary mode of SARS‐CoV‐2 infection. By contrast, SARS‐CoV‐2 has been readily cultured from nasopharyngeal (NP) swabs, saliva, blood, stool, and semen. 4,10‐12 Mounting evidence indicates that COVID‐19 patients are most infectious within the first eight days following symptom onset, 4,12,13 with some outliers shedding live virus for up to 18 days. 13,14 Increased viral load is associated with better odds of culturing virus, with cut‐off values reported at 24 and 34 RT‐PCR cycle thresholds. 4,13 Building on previous work carried out by our team, 15 we sought to enroll home isolated SARS‐CoV‐2 positive patients early in their disease progression to estimate the viability of the virus in biological, environmental, and bioaerosol samples and assess aerosol transmission of SARS‐CoV‐2. Viral RNA was extracted from processed samples using QIAamp Viral RNA Mini Kits (QIAGEN, Hilden, Germany), with the resultant product used in an adapted Center for Disease Control and Prevention (CDC) 2019‐nCoV real‐time RT‐PCR assay. 15 Specimens with molecular evidence of SARS‐CoV‐2 infection were inoculated onto VeroE6/TMPRSS2 cells 20 using 250 µl of sample for 7 days. Two forms of aerosol sampling (NIOSH BC 251 Cyclone Sampler and SKC 20 ml BioSampler) were simultaneously employed at varying distances from the participant's head Patient Sample Type a N1 (Ct) b N2 (Ct) b Culture Results c Fomites Ct Range for N1 and N2 b Culture Results c Aerosol Samples Ct Range for N1 and N2 b Culture Results c 1 Saliva 29.0 37.1 N ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ 2 Saliva 38.2 39.0 N ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ ‐‐ 3 NP Swab 16.9 17.3 P Cell phone, sink handle (bathroom) 29.0 ‐ 39.0 N 1 m ‐ SKC; 1.4 m ‐ NIOSH 36.1 ‐ 38.6 N Saliva 29.1 33.7 P Rectal Swab 35.0 34.6 N 4 NP Swab 17.3 18.7 P Cell phone, TV remote, bathroom door knob 33.4 ‐ 39.4 N 1.4 m ‐ SKC; 2.2 m ‐ SKC 36.4 ‐ 39.8 N Saliva 18.2 19.3 P Rectal Swab 35.3 37.5 N 5 NP Swab 17.9 18.6 P Cell phone 37.8 ‐ 38.7 N 1.4 m ‐ NIOSH 36.9 N Saliva 29.5 31.6 P Rectal Swab 34.1 37.0 N 6 NP Swab 15.0 15.9 P Cell phone, bathroom door knob, computer 36.7 ‐ 39.6 N 1 m ‐ NIOSH; 1.4 m ‐ NIOSH, SKC; 2.2 m ‐ NIOSH, SKC 31.8 ‐ 39.9 N Saliva 24.4 27.3 P Rectal Swab 31.3 33.5 N 7 NP Swab 18.1 18.6 P Toilet handle 36.7 ‐ 38.6 N ‐‐ ‐‐ ‐‐ Saliva 24.7 25.5 P Rectal Swab 29.6 31.2 P 8 NP Swab 25.6 26.7 P TV remote, computer (mouse) 27.0 ‐ 39.3 N ‐‐ ‐‐ ‐‐ Saliva 31.2 32.4 N Rectal Swab 39.8 39.7 N aNP=nasopharyngeal; bCt=cycle threshold; cP=positive and N=negative =the patient's spouse (also SARS‐CoV‐2 positive) was present during sampling.
•Avian H9N2 viruses may be common among live bird market poultry in Pakistan•These viruses may occasionally spillover to infect humans•Surveillance for influenza viruses is needed in Pakistan's live ...bird markets
This study sought to detect and characterize influenza A (IAV) and influenza D (IDV) viruses circulating among commercial birds and shop owners in Pakistan's live bird markets.
Oropharyngeal swabs (n=600; n=300 pools) collected from poultry and nasopharyngeal swabs (n=240) collected from poultry workers were studied for molecular evidence of IAV and IDV using real-time and conventional RT-PCR protocols.
Nineteen (6.3%) poultry pools were positive for IAV and 73.9% of these were positive for H9N2 subtypes. Two (0.83%) poultry workers had evidence of IAV, and both were also H9N2 subtypes. The poultry and human influenza A-positive specimens all clustered phylogenetically by Sanger and next-generation sequencing with previously detected H9N2 poultry isolates. No field specimens were positive for IDV.
H9N2 IAV is likely enzootic in Punjab Province Pakistan's live bird markets and may be colonizing the noses of workers and market visitors. Regular monitoring for avian influenza-associated human illness in Punjab seems to be a needed public measure.
PDF
