To evaluate the performance of an ultrafast single-tube nucleic acid isothermal amplification detection assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA using clinical ...samples from multiple centres.
A reverse transcription recombinase–aided amplification (RT-RAA) assay for SARS-CoV-2 was conducted within 15 minutes at 39°C with portable instruments after addition of extracted RNA. The clinical performance of RT-RAA assay was evaluated using 947 clinical samples from five institutions in four regions of China; approved commercial fluorescence quantitative real-time PCR (qRT-PCR) kits were used for parallel detection. The sensitivity and specificity of RT-RAA were compared and analysed.
The RT-RAA test results of 926 samples were consistent with those of qRT-PCR (330 were positive, 596 negative); 21 results were inconsistent. The sensitivity and specificity of RT-RAA was 97.63% (330/338, 95% confidence interval (CI) 95.21 to 98.90) and 97.87% (596/609, 95% CI 96.28 to 98.81) respectively. The positive and negative predictive values were 96.21% (330/343, 95% CI 93.45 to 97.88) and 98.68% (596/604, 95% CI 97.30 to 99.38) respectively. The total coincidence rate was 97.78% (926/947, 95% CI 96.80 to 98.70), and the kappa was 0.952 (p < 0.05).
With comparable sensitivity and specificity to the commercial qRT-PCR kits, RT-RAA assay for SARS-CoV-2 exhibited the distinctive advantages of simplicity and rapidity in terms of operation and turnaround time.
Abstract Breast magnetic resonance imaging (MRI) has been proposed as an additional screening test for young women at high risk of breast cancer in whom mammography alone has poor sensitivity. We ...conducted a systematic review to assess the effectiveness of adding MRI to mammography with or without breast ultrasound and clinical breast examination (CBE) in screening this population. We found consistent evidence in 5 studies that adding MRI provides a highly sensitive screening strategy (sensitivity range: 93–100%) compared to mammography alone (25–59%) or mammography plus ultrasound +/− CBE (49–67%). Meta-analysis of the three studies that compared MRI plus mammography versus mammography alone showed the sensitivity of MRI plus mammography as 94% (95%CI 86–98%) and the incremental sensitivity of MRI as 58% (95%CI 47–70%). Incremental sensitivity of MRI was lower when added to mammography plus ultrasound (44%, 95%CI 27–61%) or to the combination of mammography, ultrasound plus CBE (31–33%). Estimates of screening specificity with MRI were less consistent but suggested a 3–5-fold higher risk of patient recall for investigation of false positive results. No studies assessed as to whether adding MRI reduces patient mortality, interval or advanced breast cancer rates, and we did not find strong evidence that MRI leads to the detection of earlier stage disease. Conclusions about the effectiveness of MRI therefore depend on assumptions about the benefits of early detection from trials of mammographic screening in older average risk populations. The extent to which high risk younger women receive the same benefits from early detection and treatment of MRI-detected cancers has not yet been established.
Objectives
Pro-, pre-, and synbiotic supplements improve cardiovascular risk factors. However, the association between nonfood pro-, pre-, and synbiotics (NPPS) and long-term all-cause and ...cardiovascular mortality has not been studied. Thus, our objective was to determine the impact of nonfood pro-, pre-, and synbiotics on all-cause and cardiovascular mortality.
Design, Setting, and Participants
This was a retrospective, cohort study of 4837 nationally representative American participants aged 65 years or older with a median follow-up duration of 77 months.
Measurements
All-cause and cardiovascular mortality were measured.
Results
A total of 1556 participants died during the median 77-month follow-up, and 517 died from cardiovascular disease. Compared with participants without NPPS use, participants who used NPPS experienced a reduced risk of all-cause mortality by nearly 41% (hazard ratio 0.59, 95% CI 0.43 to 0.79) and cardiovascular mortality by 52% (HR 0.48, 95% CI 0.30 to 0.76). Such an effect persisted in most subgroup analyses and complete-case analyses.
Conclusion and Relevance
In this study, we found a protective effect of NPPS against all-cause and cardiovascular mortality in Americans aged 65 years or older. Nonfood pro-, pre-, and synbiotics can be a novel, inexpensive, low-risk treatment addition for all-cause and cardiovascular mortality for older individuals.
Abstract
‘Internal plateau’ followed by a sharp decay is commonly seen in short gamma-ray burst (GRB) light curves. The plateau component is usually interpreted as the dipole emission from a ...supra-massive magnetar, and the sharp decay may imply the collapse of the magnetar to a black hole (BH). Fall-back accretion on to the new-born BH could produce long-lasting activities via the Blandford–Znajek (BZ) process. The magnetic flux accumulated near the BH would be confined by the accretion discs for a period of time. As the accretion rate decreases, the magnetic flux is strong enough to obstruct gas infall, leading to a magnetically arrested disc. Within this scenario, we show that the BZ process could produce two types of typical X-ray light curves: type I exhibits a long-lasting plateau, followed by a power-law (PL) decay with slopes ranging from 5/3 to 40/9; type II shows roughly a single PL decay with a slope of 5/3. The former requires low magnetic field strength, while the latter corresponds to relatively high values. We search for such signatures of the new-born BH from a sample of short GRBs with an internal plateau, and find two candidates: GRB 101219A and GRB 160821B, corresponding to type II and type I light curves, respectively. It is shown that our model can explain the data very well.
In this work, GaSb is proposed as a new alternative substrate for the growth of HgCdTe via molecular beam epitaxy (MBE). Due to the smaller mismatch in both lattice constant and coefficient of ...thermal expansion between GaSb and HgCdTe, GaSb presents a better alternative substrate for the epitaxial growth of HgCdTe, in comparison to alternative substrates such as Si, Ge, and GaAs. In our recent efforts, a CdTe buffer layer technology has been developed on GaSb substrates via MBE. By optimizing the growth conditions (mainly growth temperature and VI/II flux ratio), CdTe buffer layers have been grown on GaSb substrates with material quality comparable to, and slightly better than, CdTe buffer layers grown on GaAs substrates, which is one of the state-of-the-art alternative substrates used in growing HgCdTe for the fabrication of mid-wave infrared detectors. The results presented in this paper indicate the great potential of GaSb to become the next generation alternative substrate for HgCdTe infrared detectors, demonstrating MBE-grown CdTe buffer layers with rocking curve (double crystal x-ray diffraction) full width at half maximum of ∼60 arcsec and etch pit density of ∼10
6
cm
−2
.
Demand for high-performance HgCdTe infrared detectors with larger array size and lower cost has fuelled the heteroepitaxial growth of HgCdTe on CdTe buffer layers on lattice-mismatched alternative ...substrates such as Si, Ge, GaAs and GaSb. However, the resulting high threading dislocation (TD) density in HgCdTe/CdTe limits their ultimate application. Herein, strained CdZnTe/CdTe superlattice layers have been used as dislocation filtering layers (DFL) to reduce the TDs in CdTe buffer layers grown on GaAs (211)B substrates (14.4% lattice-mismatch) by molecular beam epitaxy (MBE). Cross-sectional microstructure characterization indicates that the DFLs suppress the propagation of TDs. For optimal Zn content combined with thermal annealing, the DFLs effectively reduce the defect density of the upper-most CdTe layer from low-10
7
cm
−2
to the critical level of below 10
6
cm
−2
. In comparison to conventional buffer CdTe layers, the in-plane lattice of the CdTe layers in/near the DFL region is compressively strained, leading to a spread in x-ray double-crystal rocking curve full-width at half-maximum values but better in-plane lattice-matching with HgCdTe. The combined advantages of lower dislocation density and better lattice-matching with HgCdTe indicate that the DFL approach is a promising path towards achieving heteroepitaxy of high-quality HgCdTe on large-area lattice-mismatched substrates for fabricating next-generation infrared detectors.
As survival prospects improve for long-term patients with hemodialysis, it is common for patients to exhaust all upper extremity access options before other avenues need exploration. The purpose of ...this case report was to describe our experience in creating a prosthetic graft between left femoral artery and right femoral vein in a patient with history of central venous occlusion and bilateral femoral neck fracture.
A female patient with hemodialysis exhausted all upper extremity access options along with bilateral femoral neck fracture.
Patients with end-stage renal disease exhausted all upper extremity access options.
We performed a left femoral artery to right femoral vein dialysis access utilizing a prosthetic graft and autologous cephalic vein.
The graft was used for hemodialysis 3 weeks after the operation. There was no edema of the lower extremity through the immediate postoperative period as well as at follow up. The patient has been using the access for 9 months with no complication of thrombosis, infection, or bleeding.
Prosthetic graft between the left femoral artery and right femoral vein is a simple, safe and novel approach to creating lower extremity access. This method could be a viable means of hemodialysis access in selected patients.
Postdental procedure bacteremia is common and troublesome. The comparative efficacy of multiple prophylactic interventions is unclear. We compared the efficacy of interventions for the prevention of ...postdental procedure bacteremia. We conducted a review of ClinicalKey, Cochrane CENTRAL, Embase, ProQuest, PubMed, ScienceDirect, Web of Science, and ClinicalTrials.gov from inception to December 4, 2018. Randomized controlled trials that evaluated prophylactic interventions for the prevention of postdental procedure bacteremia were eligible. The primary outcome was the incidence of postdental procedure bacteremia. A total of 24 trials were included with 2,147 participants. Our network meta-analysis demonstrated that intravenous administration of 1,000/200 mg of amoxicillin/clavulanate provided the least incidence of postdental procedure bacteremia among all the prophylactic interventions (odds ratio = 0.03, 95% CI = 0.00 to 0.63) as compared with the placebo/controls. Oral 3 g of amoxicillin had the least incidence of postdental procedure bacteremia among all oral or topical forms of prophylactic interventions (odds ratio = 0.10, 95% CI = 0.02 to 0.44) as compared with the placebo/controls. No serious adverse events, such as anaphylactic shock, mortality, and the development of antibiotic-resistant bacteria, were reported. None of the included subjects were of high risk of infectious endocarditis. Our network meta-analysis demonstrates that intravenous amoxicillin/clavulanate and oral amoxicillin might be the best prophylactic interventions in preventing postdental procedure bacteremia among all the oral/topical forms of interventions for the overall populations.
•A low dislocation density molecular beam epitaxial process.•Transitional buffer layer for reducing dislocations in epitaxial layers.•GaSb provides an alternative substrate for growing HgCdTe ...infrared materials.
This work demonstrates a low dislocation density molecular beam epitaxial process (average etch pit density ∼1.4 × 105 cm−2) for the growth of CdTe buffer layers on GaSb (211)B alternative substrates for subsequent growth of HgCdTe infrared materials. This dislocation density is much lower than that for CdTe layers grown on other alternative substrates (mid-106 to low-107 cm−2 range for Si, Ge and GaAs), is well below the critical level required for fabricating high performance long-wave infrared HgCdTe detectors (5 × 105 cm−2), and is close to that achieved on lattice-matched CdZnTe substrates (mid-104 to low-105 cm−2 range). The low dislocation density is achieved by inserting a ZnTe/CdTe-based transitional buffer layer between the GaSb substrate and the CdTe buffer layer. The main purpose of this transitional buffer layer is to better accommodate the 6.1% lattice mismatch between the GaSb substrate and the CdTe epitaxial layer, which is evidenced by X-ray diffraction reciprocal space mapping. Additional benefits of this transitional buffer layer include possible blocking/filtering of misfit dislocation propagation, as well as gettering of defects and impurities. More importantly, an even lower dislocation density can be expected by increasing the thickness of the CdTe epitaxial layer and implementing a thermal annealing cycle for more efficient gettering. The results of this study indicate the great potential of GaSb as an alternative substrate for growing next generation HgCdTe infrared materials to meet the focal plane array requirements of higher device yield, lower cost and larger array format size.
The local and regional impacts of open fires and trash burning on ground-level ozone (O sub(3)) and fine carbonaceous aerosols in the Mexico City Metropolitan Area (MCMA) and surrounding region ...during two high fire periods in March 2006 have been evaluated using WRF-CHEM model. The model captured reasonably well the measurement-derived magnitude and temporal variation of the biomass burning organic aerosol (BBOA), and the simulated impacts of open fires on organic aerosol (OA) were consistent with many observation-based estimates. We did not detect significant effects of open fires and trash burning on surface O sub(3) concentrations in the MCMA and surrounding region. In contrast, they had important influences on OA and elemental carbon (EC), increasing primary OA (POA) by similar to 60%, secondary OA (SOA) by similar to 22%, total OA (TOA = POA + SOA) by similar to 33%, and EC by similar to 22%, on both the local (urban) and regional scales. Although the emissions of trash burning are substantially lower than those from open fires, trash burning made slightly smaller but comparable contributions to OA as open fires did, and exerted an even higher influence on EC. Of the similar to 22% enhancement in SOA concentrations (equivalent to a similar to 15% increase in TOA) simulated, about two third was attributed to the open fires and one-third to the trash burning. On the annual basis and taking the biofuel use emissions into consideration, we estimated that open fires, trash burning and biofuel use together contributed about 60% to the loading of POA, 30% to SOA, and 25% to EC in both the MCMA and its surrounding region, of which the open fires and trash burning contributed about 35% to POA, 18% to SOA, and 15% to EC. The estimates of biomass burning impacts in this study may contain considerable uncertainties due to the uncertainties in their emission estimates in magnitude, temporal and spatial distribution, extrapolations and the nature of spot comparison. More observation and modeling studies are needed to accurately assess the impacts of biomass burning on tropospheric chemistry, regional and global air quality, and climate change.
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