Abstract
Objectives
Rates of Clostridioides (Clostridium) difficile infection (CDI) are higher in North Wales than elsewhere in the UK. We used WGS to investigate if this is due to increased ...healthcare-associated transmission from other cases.
Methods
Healthcare and community C. difficile isolates from patients across North Wales (February–July 2015) from glutamate dehydrogenase (GDH)-positive faecal samples underwent WGS. Data from patient records, hospital management systems and national antimicrobial use surveillance were used.
Results
Of the 499 GDH-positive samples, 338 (68%) were sequenced and 299 distinct infections/colonizations were identified, 229/299 (77%) with toxin genes. Only 39/229 (17%) toxigenic isolates were related within ≤2 SNPs to ≥1 infections/colonizations from a previously sampled patient, i.e. demonstrated evidence of possible transmission. Independent predictors of possible transmission included healthcare exposure in the last 12 weeks (P = 0.002, with rates varying by hospital), infection with MLST types ST-1 (ribotype 027) and ST-11 (predominantly ribotype 078) compared with all other toxigenic STs (P < 0.001), and cephalosporin exposure in the potential transmission recipient (P = 0.02). Adjusting for all these factors, there was no additional effect of ward workload (P = 0.54) or failure to meet cleaning targets (P = 0.25). Use of antimicrobials is higher in North Wales compared with England and the rest of Wales.
Conclusions
Levels of transmission detected by WGS were comparable to previously described rates in endemic settings; other explanations, such as variations in antimicrobial use, are required to explain the high levels of CDI. Cephalosporins are a risk factor for infection with C. difficile from another infected or colonized case.
We explore the growth temperature dependence of GaAs/AlGaAs core/shell nanowires (NW) grown by metal–organic chemical-vapor deposition (MOCVD) on (100) and (111)B GaAs substrates. In-situ calibration ...of the growth temperature allows for a systematic variation with unprecedented resolution. Characterization by photoluminescence (PL) indicates that, at low growth temperatures, nanowires grown on (111)B substrates incorporate higher density of defects than wires on (100). On either substrate, nanowire core growth temperatures above 450°C result in rising defect luminescence in the PL spectra concomitant with the increased epitaxial growth on the nanowire sidewalls at these higher temperatures. This work presents a systematic study of nanowire growth conditions that reveals the correlation between the growth temperature of the GaAs core, the chosen substrate surface orientation, and the resulting optical properties of GaAs/AlGaAs nanowires.
•GaAs/AlGaAs core/shell nanowires (NW) are grown by metal-organic chemical-vapor deposition (MOCVD) on (100) and (111)B GaAs substrates.•Dependence of optical characteristics on growth temperature and substrate orientation are investigated.•At low core growth temperatures (below 450°C), nanowires grown on (111)B substrates incorporate higher density of defects than wires on (100).•Rising defect luminescence is observed in the PL spectra at temperatures higher than 450°C and is concomitant with the increased epitaxial growth on the nanowire sidewalls.
Using position averaged convergent beam electron diffraction (PACBED) the Jahn-Teller distortion in LaMnO_{3} is quantitatively measured using a straightforward pattern-matching approach. The fit ...between experimental patterns and PACBED patterns simulated using the quantum excitation of phonons model allows a three-dimensional measure of octahedral distortion and rotation information from the near transmitted disk region with picometer precision. The effects of plasmon and other inelastic components on quantification using this method are investigated and discussed. The results provide an avenue for accurate local studies of the crystal structure origins of emergent physics in parallel with high-resolution annular dark field scanning transmission electron microscopy imaging at interfaces and defects in quantum materials.
Cardiomyopathy (CMP) is a heritable disorder. Over 50% of cases are gene-elusive on clinical gene panel testing. The contribution of variants in non-coding DNA elements that result in cryptic ...splicing and regulate gene expression has not been explored. We analyzed whole-genome sequencing (WGS) data in a discovery cohort of 209 pediatric CMP patients and 1953 independent replication genomes and exomes. We searched for protein-coding variants, and non-coding variants predicted to affect the function or expression of genes. Thirty-nine percent of cases harbored pathogenic coding variants in known CMP genes, and 5% harbored high-risk loss-of-function (LoF) variants in additional candidate CMP genes. Fifteen percent harbored high-risk regulatory variants in promoters and enhancers of CMP genes (odds ratio 2.25, p = 6.70 × 10
versus controls). Genes involved in α-dystroglycan glycosylation (FKTN, DTNA) and desmosomal signaling (DSC2, DSG2) were most highly enriched for regulatory variants (odds ratio 6.7-58.1). Functional effects were confirmed in patient myocardium and reporter assays in human cardiomyocytes, and in zebrafish CRISPR knockouts. We provide strong evidence for the genomic contribution of functionally active variants in new genes and in regulatory elements of known CMP genes to early onset CMP.
The debate over the use of exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) in organizational research is examined. A panel of 5 experts was assembled to discuss the ...underlying issues and provide guidance for researchers interested in the use of EFA and CFA. A discussion points out how important it is for researchers to scrutinize their decision regarding the analysis they will utilize in their studies.
Objective: The document describes macular hole surgery and examines the available evidence to address questions about the efficacy of the procedure for different stages of macular hole, complications ...during and after surgery, and modifications to the technique.
A literature search conducted for the years 1968 to 2000 retrieved over 400 citations that matched the search criteria. This information was reviewed by panel members and a methodologist, and it was evaluated for the quality of the evidence presented.
There are three multicenter, controlled, randomized trials that constitute Level I evidence and compare the value of surgery versus observation for macular hole. There are three multicenter, controlled, randomized trials studying the use of adjuvant therapy in macular hole repair. Postoperative vision of 20/40 or better has been reported in 22% to 49% of patients in randomized trials. The risks of surgical complications include retinal detachment (3%), endophthalmitis (<1%), cataract (>75%), and late reopening the hole (2% to 10%).
The evidence does not support surgery for patients with stage 1 holes. Level I evidence supports surgery for stage 2 holes to prevent progression to later stages of the disease and further visual loss. Level I evidence shows that surgery improves the vision in a majority of patients with stage 3 and stage 4 holes. There is no strong evidence that adjuvant therapy used at the time of surgery results in improved surgical outcomes. Patient inconvenience, patient preference, and quality of life issues have not been studied.
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