Carrier Rate Research Articles

Antibiotic susceptibility and molecular characterization based on whole-genome sequencing of Staphylococcus aureus causing invasive infection in children and women living in Southwest China during 2018–2023

BackgroundStaphylococcus aureus is one of the most common pathogens that colonizes human skin/mucous membranes, where it causes local infection that can progress to invasive infection, resulting in high morbidity and mortality worldwide. This study aimed to investigate the antibiotic susceptibility and molecular characteristics of invasive S. aureus in children and women in Southwest China from 2018 to 2023 to provide novel insights helpful in preventing and treating S. aureus infections.MethodsThe demographic and clinical characteristics of patients with invasive S. aureus infection were collected and analyzed. Next-generation sequencing (NGS) and sequence analysis techniques were used to determine the molecular epidemiological characteristics of the S. aureus isolates, and the microdilution broth method was used for antimicrobial susceptibility testing.ResultsA total of 108 invasive S. aureus isolates, 29 methicillin-resistant S. aureus (MRSA) isolates and 79 methicillin- susceptible S. aureus (MSSA) isolates, were included. The isolates had the highest rate of resistance to PEN, at 91.67%, with all the MRSA isolates being resistant; the next highest resistance was to ERY and CLI, both at 65.74%. A total of 32 STs (including 8 novel STs) were detected and divided into 10 CCs. Moreover, 45 spa types were also detected. The main STs were ST22 (17.59%) and ST59 (15.74%), and the main CCs were CC59 (21.30%) and CC22 (19.44%). The most prevalent spa types were t309 and t437, both at 14.81%, and the SCCmec type could be assigned to two categories: IV (62.07%) and V (34.48%). Among the 29 MRSA isolates tested, CC59-IV-t437 (34.48%) and CC59-V-t437 (13.79%) were the main lineages, and among the 79 MSSA isolates, CC22-t309 (18.99%), CC1-t189 (10.13%), and CC5-t002 (7.60%) were the main lineages. Except for SXT, the resistance rates of the 29 MRSA isolates were greater than those of the MSSA isolates. Most isolates carried common virulence genes, among which the carriage rate of pvl reached 33.33%.ConclusionsThis study provides valuable information, including the prevalence, molecular characteristics and antimicrobial resistance of S. aureus isolates that cause invasive infectious diseases in Southwest China, and the findings may advance the prevention and treatment of S. aureus infections.

Detection of pneumococcal carriage in asymptomatic healthcare workers

Abstract Background Healthcare workers are at increased risk of exposure to respiratory pathogens including Streptococcus pneumoniae (pneumococcus). While little asymptomatic carriage has been reported in young-to-middle-aged adults, this may be due to non-sensitive diagnostic methods. The aim of the study was to investigate the rates of pneumococcal carriage in a large cohort of healthcare workers using saliva as a respiratory specimen. Methods We evaluated pneumococcal carriage in a convenience sample of saliva, self-collected from asymptomatic healthcare workers (CT, USA) who were testing for SARS-CoV-2 from March 30 to June 11, 2020. DNA extracted from the culture-enriched saliva was later tested using qPCR for piaB, lytA, and serotype. Saliva samples were considered positive for pneumococcus when the piaB Ct value was <40. Results Study participants were 22-74 years old (mean=38.5), 75% female, 75% white, with occupations including registered nurses (48%), medical doctors (23%), and patient care assistants (5%). Overall, 138/1241 (11%) samples from 86/392 (21%) individuals tested piaB-positive at some point during the 4-month study period, with 28 (33%) colonized individuals positive at multiple time points. Carriers reflected the overall study population. No significant demographic characteristics were associated with detection of pneumococcus. Colonized individuals primarily carried serotypes 19F (25.6%) and 3 (12.8%). Conclusions During a period of mandatory masking, we identified a cumulative pneumococcal carriage prevalence of 21% among healthcare workers. This study highlights that healthcare workers may act as unrecognized reservoirs of pneumococcus in the population. Despite long-standing pediatric immunization programs, vaccine-targeted serotypes continue to be prevalent among the adult population.

Streptococcus pyogenes carriage rate, associated factors and antimicrobial susceptibility profiles among urban and rural schoolchildren at Gondar city, Northwest Ethiopia

Streptococcus pyogenes remains one of the top ten causes of mortality from infectious diseases. Children in low-income nations have high carrier rates of Streptococcus pyogenes, which can serve as a source of infections, including simple superficial infections that may lead to invasive and post-streptococcal diseases, particularly among schoolchildren. This study aimed to assess the prevalence of Streptococcus pyogenes, associated factors, and antimicrobial susceptibility profiles among urban and rural public schoolchildren in Gondar City, Northwest Ethiopia. A school-based comparative cross-sectional study was conducted via a multistage sampling technique among elementary schoolchildren from April to June 2022 in Gondar City. Sociodemographic and clinical data were collected via a pretested structured questionnaire. Standard microbiological methods were used to collect and process throat swabs to isolate Streptococcus pyogenes. An antimicrobial susceptibility test was performed via the disk diffusion method. Epi-Info version 7.2.5 was used to enter the data, which were then exported to SPSS version 25 for analysis. Logistic regression analysis was used to determine the strength of associations between variables, and p < 0.05 was considered statistically significant. The overall prevalence of Streptococcus pyogenes in 438 children was 11.2% (n = 49), with 71.43% (35/49) being urban and 28.57% (14/49) being rural. Low-income parents, hospital admission history, and cigarette smoking in the home were found to be substantially linked with Streptococcus pyogenes carriage among students (p < 0.05). All the Streptococcus pyogenes isolates were susceptible (100%) to penicillin and cefotaxime, but 18.8% and 12.25% of the isolates were resistant to amoxicillin and tetracycline, respectively. The prevalence of Streptococcus pyogenes throat carriage among was intermediate. All the isolates were sensitive to penicillin and cefotaxime, but 18.8% and 12.25% of the isolates were resistant to amoxicillin and tetracycline, respectively. Thus, regular screening and surveillance of Streptococcus pyogenes among schoolchildren should be conducted to minimize carriage or infections and maintain the rational use of antimicrobials. Health education about cigarette smoking in the house also needs to be provided to and the community.

Structural modification of defective WO3 by g-C3N4 for photocatalytic gold recovery from non-cyanide-based plating effluent

A set of nCN/WO3 − x composites was synthesized through a simple thermal treatment for gold recovery from the simulated effluent of a non-cyanide-based plating bath. The obtained results exhibited that all nCN/WO3 − x composites demonstrated a higher photocatalytic activity for gold recovery than their pristine components due to the formation of nanocomposites which paved a convenient pathway for charge transfer. Among all synthesized composites, the 5.0CN/WO3 − x composite exhibited the highest photocatalytic activity, recovering around 69.4% of gold within 120 min under UV-vis light irradiation at an intensity of 3.45 mW/cm² and a catalyst loading of 1.0 g/L, in the absence of hole scavenger. This result can be ascribed to the presence of an optimal number of defects, which can act as electron trapping sites and thereby reduce the recombination rate of charge carriers. Gold recovery increased with repeated reuse, attributed to the decorated gold, which enhances light absorption and decreases the recombination rate of charge carriers. The feasible application of used CN/WO3 − x were also explored for H2 production, dye degradation and gold recovery. The obtained results provide a new insight about the photocatalytic recovery of gold from industrial wastewater and also shed light on the application of gold-decorated CN/WO3 − x as a catalyst for other photocatalytic applications.

Asymptomatic carriage and molecular characterization of Staphylococcus aureus in pre-clinical and clinical medical students.

Medical students are exposed to the hospital environment and patients during their studies, increasing the risk of exposure to virulent and antibiotic-resistant isolates of Staphylococcus aureus. The aim of the study is to determine the prevalence of Staphylococcus aureus among medical students who have varying levels of exposure to the hospital environment to provide valuable insights into the risk of colonization and transmission. Nasal swabs and fingerprints were obtained and cultured on a selective medium for staphylococci. The obtained isolates were confirmed as methicillin-sensitive S. aureus (MSSA) or methicillin-resistant (MRSA) using PCR. Antibiotic resistance, the presence of virulence genes including enterotoxin encoding genes, and spa typing were performed. Among pre-clinical students, MSSA was detected on the nose in 45.2% and on the fingerprints in 10.6% of the participants. Among clinical students, MSSA was detected on the nose in 42.0% and on the fingerprints in 25.4%. Only one MRSA isolate was obtained. Genes seg and sei were the most frequently detected in both student groups, with their presence in over 40% of isolates among clinical students. The eta and etb genes were mainly detected from the nose in both student groups. In pre-clinical students, S. aureus carrying eta gene occurred in 6.4% and etb in 8.5%. In clinical students, the occurrence was 5.1% for eta and 8.5% for etb. The tst gene was identified only in the nose and fingerprints of the clinical student group. The most frequently observed resistance was to clindamycin and erythromycin. In total 58 different spa types were identified. High rates of asymptomatic MSSA carriage were observed in both groups of medical students. Detected MSSA strains showed a high degree of genetic variability, with a number of them carrying the virulence and antibiotic resistance genes. Although students do not exhibit increased risk to their patient's, increased hygiene is required in asymptomatic carriage personnel. The overall prevalence of MRSA was low, with a minimal risk of spread.

Machine Learning in Healthcare: A Comprehensive Review of Predictive Models for COVID-19 Transmission among Vaccinated Individuals

This review provides an in-depth exploration of machine learning (ML) applications in healthcare, focusing specifically on predictive models for COVID-19 transmission among vaccinated individuals. It underscores the pivotal role of ML in disease forecasting and prognosis, showcasing its potential to enhance healthcare outcomes in pandemic contexts. Key challenges of COVID-19, such as the high transmission rate of asymptomatic carriers and the effectiveness of containment strategies, are analyzed to highlight areas where ML can offer significant advantages. The study aims to develop an advanced forecasting model for COVID-19 transmission using diverse supervised ML regression techniques, including linear regression, LASSO, support vector machine, and exponential smoothing, applied to an extensive COVID-19 patient dataset. The insights generated from this review support efforts to combat COVID-19 and improve public health strategies, demonstrating ML's vital contribution to pandemic management and healthcare resilience.

Modification of surface properties and photocatalytic performance of pure and oxygen-doped graphitic carbon nitride via DBD plasma treatment

Graphitic carbon nitride (CN) is a non-metallic semiconductor with applications in photocatalysis, including the photocatalytic reduction of Cr(VI) under visible irradiation. To improve its intrinsic properties, two modification strategies were applied: i) oxygen doping by co-calcination of urea with two different amounts of oxalic acid, and ii) dielectric barrier discharge (DBD) plasma treatment. The plasma treatment was applied to pristine and previously oxygen-doped CNs. The properties of the photocatalysts were studied by XRD, FTIR, FESEM, EDS, PL and DRS analysis, as well as by determination of the number of acidic surface functional groups. Both modification methods increased the oxygen content: during oxygen doping, nitrogen was replaced by oxygen in the lattice, while during plasma treatment, oxygen-containing functional groups were introduced at the surface. Plasma treatment of oxygen-doped CNs facilitated surface functionalisation due to the open heptazine ring structure. Oxygen doping narrowed the band gap, which was further slightly reduced by subsequent plasma treatment, thereby lowering the oxidation and reduction potentials. Although the absorption of visible light was improved, the reduction of the band gap resulted in a reduced activity for the photocatalytic reduction of Cr(VI). The best results were obtained with plasma-treated pure CN, due to the increased content of oxygen-containing surface groups, which led to a slightly reduced recombination rate of charge carriers.

Cerebrotendinous Xanthomatosis occurs at high frequency in Ashkenazi Jews.

Cerebrotendinous Xanthomatosis (CTX) is a treatable, inborn error of bile acids metabolism caused by pathogenic variants in CYP27A1. CTX is a multi-organ system disorder that progresses over decades. Clinical features include cerebellar dysfunction, pyramidal tract dysfunction, cognitive deficits and decline, peripheral neuropathy, chronic diarrhea, bilateral cataracts, and tendon xanthomas. Treatment is effective when started early, but diagnostic delays often result in individuals not being diagnosed until after the window of highest treatment efficacy. CTX is documented to occur in most global populations, however, no CTX-causing genetic variants have been reported in Ashkenazi Jews. We conducted a systematic review of every case of CTX reported in a person identified as Jewish and the specific CYP27A1 variants present. We also leveraged the Israeli Medical Genetics Database and the population genetics data resource gnomAD to identify CTX-causing alleles in Ashkenazi Jews. We found that there are three pathogenic CYP27A1 variants in the Ashkenazi Jewish population segregating at an appreciable frequency, with a gene carrier rate of 0.002 based on the gnomAD Ashkenazi Jewish data. One pathogenic variant appears only in the Ashkenazi Jewish group in gnomAD, which contains genetic data from across the globe. We compared the carrier frequency for CTX to the carrier frequencies for diseases that are commonly included in carrier screening for Ashkenazi Jews. These results show that CTX occurs in Ashkenazi Jews, and that both Sephardi and Ashkenazi Jews may benefit from newborn and carrier screening for CTX.

Prevalence and pattern of carriage of Enterobacterales isolates among food handlers in Nnewi metropolis, southeast Nigeria

Background: There is a public health concern about carriage of Enterobacterales among food workers and their potential role for transmission of food-borne illnesses. Food contamination by Enterobacterales could happen at any point of the production, processing, distribution, and preparation processes. This challenge is especially severe in developing countries like Nigeria. The objective of this study is to determine the prevalence and pattern of carriage of Enterobacterales by food handlers in Nnewi metropolis, southeast Nigeria.Methodology: This was a cross-sectional study that employed a non-probability sampling technique to recruit 178 food handlers who gave their consent and were available at the sampling area during the time of the study. Stool, urine, nasal and hand swab samples were collected from 115, 116, 120 and 173 food handlers respectively for microbiological analysis using conventional culture isolation and biochemical identification by Analytical Profile Index (API) 20E (bioMérieux). The antimicrobial susceptibility testing of the isolates was carried out on the identified isolates by the disk diffusion method. Descriptive statistics were carried out on the data.Results: Forty-four (25.4%) of the hand swab samples from 173 food handlers, 39 (32.5%) of the nasal swabs from 120 food handlers, 67 (58.3%) of the stool samples from 115 food handlers, and 29 (25.0%) of the urine samples from 116 food handlers, were positive for Enterobacterales isolates. The frequency of Enterobacterales isolation was significantly higher from stool samples compared to other samples (x2=40.032; p&lt;0.0001), indicating a higher carriage rate in the gastrointestinal tracts of the food handlers. Across all the samples, a total of 179 Enterobacterales were isolated from the 101 (56.7%) positive food handlers. The frequency of isolation in descending order is Escherichia coli 23.2% (n=41), Klebsiella spp 18.1% (n=32), Enterobacter spp 15.3% (n=27), Citrobacter spp 10.7% (n=19), Raoultella spp 7.3% (n=13), Serratia spp 5.6% (n=10), Salmonella spp 3.9% (n=7), Kluyvera spp 3.9% (n=7), Shigella spp 2.8% (n=5), Proteus spp 2.8% (n=5), Cronobacter spp 1.7% (n=3), Erwinia spp 1.1% (n=2), Pantoea spp 1.1% (n=2), Hafnia spp 1.1% (n=2), and Yersinia spp 1.1% (n=2). The Enterobacterales isolates were resistant to cefotaxime (83.0%), amoxicillin-clavulanic acid (79.1%), cefuroxime (76.8%), cefixime (75.1%), imipenem-cilastatin (74.6%), ceftazidime-avibactam (73.3%), ceftriaxone-sulbactam (71.2%) and levofloxacin (70.5%).Conclusion: Food handlers in this study had a high carriage rate of resistant Enterobacterales pathogens, which can be transmitted to unsuspecting consumers, through the food processing and handling chains.

Gastrointestinal carriage of carbapenemase-producing enterobacterales among inpatient and outpatient children in Kenya

Gastrointestinal carriage of antimicrobial-resistant bacteria, especially carbapenemase-producing Enterobacterales (CPE), presents a critical public health threat globally. However, in many resource-constrained countries, epidemiological data on CPE is limited. Here, we assessed gastrointestinal carriage and associated factors of CPE among inpatient and outpatient children (≤ 5 years). This hospital-based cross-sectional study was conducted at Thika Level 5 Hospital in Kenya from February to June 2023. In total, 540 participants were recruited from outpatient (270) and inpatient (270) children, excluding those admitted for < 48 h and outpatients with ≤ 3 months hospitalization history. Demographic data were collected using a questionnaire, and stool or swab samples were cultured following standard microbiology methods. Automated platforms were used for isolates identification and antimicrobial susceptibility testing. Gastrointestinal carriage rate of CPE was 9.6%, 95% confidence interval (CI): 6.39–13.79% (26/270) among the inpatients and 5.9%, 95% CI: 3.42–9.45% (16/270) among the outpatients. The carbapenemase-producing Enterobacterales were predominated by multidrug-resistant Escherichia coli from inpatients (22/22, 100%) and outpatients (8/10, 80%). The colonization rate was higher among inpatients who were presenting with chills (aOR = 10.57, p = 0.008). We report a high gastrointestinal carriage of CPE among children (≤ 5 years). Strict adherence to colonization screening, and antimicrobial stewardship policies are critical to control CPE dissemination in the current study area and beyond.

Heterogeneous Interface Engineering of 2D Black Phosphorus-Based Materials for Enhanced Photocatalytic Performance.

Photocatalysis has garnered significant attention as a sustainable approach for energy conversion and environmental management. 2D black phosphorus (BP) has emerged as a highly promising semiconductor photocatalyst owing to its distinctive properties. However, inherent issues such as rapid recombination of photogenerated electrons and holes severely impede the photocatalytic efficacy of single BP. The construction/stacking mode of BP with other nanomaterials decreases the recombination rate of carriers and extend its functionalities. Herein, from the perspective of atomic interface and electronic interface, the enhancement mechanism of photocatalytic performance by heterogeneous interface engineering is discussed. Based on the intrinsic properties of BP and corresponding photocatalytic principles, the effects of diverse interface characteristics (point,linear, and planar interface) and charge transfer mechanisms (type I, type II, Z-scheme, and S-scheme heterojunctions) on photocatalysis are summarized systematically. The modulation of heterogeneous interfaces and rational regulation of charge transfer mechanisms can enhance charge migration between interfaces and even maximize redox capability. Furthermore, research progress of heterogeneous interface engineering based on BP is summarized and their prospects are looked ahead. It is anticipated that a novel concept would be presented for constructing superior BP-based photocatalysts and designing other 2D photocatalytic materials.

Comparison of nasopharyngeal bacteriological profile between patients with diabetes and healthy individuals in Accra, Ghana

BackgroundThe nasopharynx is characterised by a rich microbial diversity, making it an important endogenous reservoir for respiratory infections. People living with diabetes (PLWD) have a high risk for acquisition of respiratory tract infections, but their nasopharyngeal bacterial flora have rarely been investigated.AimTo investigate the nasopharyngeal bacterial flora among PLWD and non-diabetics at the Korle Bu Teaching Hospital in Accra.MethodologyThis study was a case-control one, involving 130 each of PLWD and non-diabetics. Nasopharyngeal swab specimens were obtained from the participants and cultured for bacteria, which were identified using MALDITOF mass spectrometry.ResultsThe bacterial flora present in the anterior nares of the participants of both study groups was characterised by a rich diversity, comprising both Gram-positives and Gram-negatives. In the diabetics, the dominant bacteria were Acinetobacter baumannii (19.6%), Staphylococcus epidermidis (18.12%), Staphylococcus aureus (15.2%), and Rahnella aquatilis (12.3%). In the control group, however, the dominant bacteria were Staphylococcus epidermidis (21.9%), Staphylococcus aureus (19.0%), Proteus mirabilis (10.9%), Pseudomonas aeruginosa (10.2%), Acinetobacter baumannii (8.8%), and Enterobacter cloacae (7.2%). Between groups, Acinetobacter baumannii (19.6% vs. 8.8%, p = 0.014) and Rahnella aquatilis (12.3% vs. 0.0%, p < 0.001) recorded a significantly higher prevalence in the diabetes group than in the control group. On the contrary, Klebsiella pneumoniae (0.0% vs. 4.4%, p = 0.003), Proteus mirabilis (2.2% vs. 10.9%, p = 0.006), and Pseudomonas aeruginosa (0.7% vs. 10.2%, p < 0.001) had significantly lower prevalence than in the control group.ConclusionThe nasopharyngeal bacterial flora of PLWD in Accra seems to have comparable diversities with those of non-diabetics. Nonetheless, the PLWD had a higher carriage rate of Acinetobacter baumannii but seem to have some protection against carriage of Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa.

Molecular pathogen profiling of COVID-19 coinfections

ObjectiveThis study aims to investigate the prevalence, pathogen spectrum, clinical characteristics, and prognosis-related factors of other respiratory pathogens in COVID-19-infected patients, and to explore the application of molecular detection methods in the epidemiological investigation of multiple pathogen infections.MethodsRespiratory samples and clinical data from 384 patients with outpatient and inpatient respiratory infections were collected and analyzed. Multiplex PCR and capillary electrophoresis were conducted to detect the distribution characteristics of 26 pathogen species, comprising 13 viruses, 13 bacteria. Statistical analysis explored the relationship between pathogen distribution with COVID-19 development.ResultsThere was no statistical difference in prognosis between the 230 COVID-19-positive patients and the 154 COVID-19-positive patients. COVID-19 cases co-infected with other pathogens do not correlate with patient’s age and gender. The main distribution of pathogens was mainly mecA (n = 62, 26.96%), followed by SPN(n = 61; 26.52%) and KP(n = 22; 9.57%). Compared with non-COVID-19 cases, COVID-19 infected patients showed a significantly higher mecA carrying rate (26.96% vs. 15.58%, P < 0.01), while there was no statistical difference for other pathogens. Regression analysis found that mecA and KP were independent risk factors for severe illnesses (mechanical ventilation, endotracheal intubation, ECOMO, etc.) or death in COVID-19 patients had 2.391 times and 3.722 times risk of severe disease or death compared with COVID-19 patients without mecA and KP.ConclusionCOVID-19 patients show a higher mecA carrier rate than non-COVID-19 patients, and mecA and KP may increase the risk of severe disease or death in COVID-19 patients, which requires close attention.

Prevalence of nasopharyngeal Streptococcus Pneumoniae carriage in infants: A systematic review and meta-analysis of cohort studies and randomized controlled trials.

This study aims to examine the prevalence of nasopharyngeal Streptococcus pneumoniae carriage (NSPC) in infants during their first two years of life and to compare the carriage rates among different vaccine groups and country income-levels. This will be achieved through a systematic review of the published literature, specifically focusing on data from cohort studies and randomized controlled trials. A comprehensive search was conducted in four electronic databases: PubMed, Web of Science, ScienceDirect, and Scopus, using a predefined search strategy. Forty-nine articles met the inclusion criteria for this systematic review. According to the results obtained from the random effects model, the pooled mean prevalence of NSPC was 1.68% at birth (95% CI [0.50; 5.47]), 24.38% at 1 to 4 months (95% CI [19.06; 30.62]), 48.38% at 4 to 6 months (95% CI [41.68; 55.13]), 59.14% at 7 to 9 months (95% CI [50.88; 66.91]), 48.41% at 10 to 12 months (95% CI [41.54; 55.35]), 42.00% at 13 to 18 months (95% CI [37.01; 47.16]), and 48.34% at 19 to 24 months (95% CI [38.50; 58.31]). The highest NSPC rates were observed among children aged 4 to 6 months and 7 to 9 months across all vaccine groups. Low-income countries consistently demonstrated the highest NSPC rates across all age categories studied. This systematic review and meta-analysis provide robust evidence of the high prevalence of NSPC in infants aged 4 to 6 months and 7 to 9 months in all vaccine groups, with persistent regional disparities, especially among low-income countries. The study highlights the need for continuous monitoring of NSPC trends, particularly the emergence of non-vaccine serotypes. Policymakers and healthcare providers should leverage these findings to enhance vaccination strategies, aiming to minimize the overall burden of pneumococcal diseases in infants.

Structural, electronic, vibrational, optical and thermoelectric properties of 1T-Na2O monolayer via MD and DFT study

Abstract Density Functional Theory (DFT) was implemented to determine the physical properties of the 1T-Na2O monolayer with the aid of WIEN2k software. To determine the electronic property exchange correlation such as GGA and hybrid functionals were implemented. The electronic property studies unveiled the 1T-Na2O monolayer as a direct bandgap semiconductor that has band gap values of 1.68 eV and 2.75 eV with GGA and hybrid correlation functionals. The dynamical stability of the 1T-Na2O monolayer was established by harnessing Phonon dispersion analysis, while the thermal stability was established by harnessing the Ab-initio Molecular Dynamics (AIMD). The optical properties investigation revealed that the 1T-Na2O monolayer shows an excellent absorption coefficient in the UV region and has a potential application in optoelectronic applications. The 1T-Na2O monolayer shows promise for waste heat recovery systems due to its thermoelectric properties, with a figure of merit of 0.82 at 400 K. The effective masses of electrons and holes (charge carriers) are determined. The relative ratio was estimated to determine the recombination rate of charge carriers and was found to be limited.

Photo-Excited Carrier Dynamics in Ammonothermal Mn-Compensated GaN Semiconductor.

We investigated the carrier dynamics of ammonothermal Mn-compensated gallium nitride (GaN:Mn) semiconductors by using sub-bandgap and above-bandgap photo-excitation in a photoluminescence analysis and pump-probe measurements. The contactless probing methods elucidated their versatility for the complex analysis of defects in GaN:Mn crystals. The impurities of Mn were found to show photoconductivity and absorption bands starting at the 700 nm wavelength threshold and a broad peak located at 800 nm. Here, we determined the impact of Mn-induced states and Mg acceptors on the relaxation rates of charge carriers in GaN:Mn based on a photoluminescence analysis and pump-probe measurements. The electrons in the conduction band tails were found to be responsible for both the photoconductivity and yellow luminescence decays. The slower red luminescence and pump-probe decays were dominated by Mg acceptors. After photo-excitation, the electrons and holes were quickly thermalized to the conduction band tails and Mg acceptors, respectively. The yellow photoluminescence decays exhibited a 1 ns decay time at low laser excitations, whereas, at the highest ones, it increased up to 7 ns due to the saturation of the nonradiative defects, resembling the photoconductivity lifetime dependence. The fast photo-carrier decay time observed in ammonothermal GaN:Mn is of critical importance in high-frequency and high-voltage device applications.

The POINTER Imaging baseline cohort: Associations between multimodal neuroimaging biomarkers, cardiovascular health, and cognition.

The U.S. Study to Protect Brain Health Through Lifestyle Intervention to Reduce Risk (U.S. POINTER) is evaluating lifestyle interventions in older adults at risk for cognitive decline and dementia. Here we characterize the baseline data set of the POINTER Imaging ancillary study. Participants underwent health and cognitive assessments and neuroimaging with multimodal positron emission tomography (PET) (beta-amyloid [Aβ] and tau) and magnetic resonance imaging (MRI). Framingham risk score (FRS) was used to quantify cardiovascular disease (CVD) risk. A total of 1052 participants (31% from underrepresented ethnoracial groups) were enrolled. Compared to Aβ-, Aβ+ (29%) participants were older, had higher apolipoprotein E (APOE) ε4 carriage rate and white matter hyperintensity volume, and greater temporal tau. FRS was related to MRI measures, but not AD biomarkers. FRS and tau had independent effects on cognition. In this heterogenous, at-risk cohort, CVD risk was related to more abnormal brain structure and poorer cognition, representing a putative non-AD (Alzheimer's disease) pathway to brain injury and cognitive decline. ·The U.S. Study to Protect Brain Health Through Lifestyle Intervention to Reduce Risk (U.S. POINTER) cohort is enriched for cardiovascular disease (CVD) and poor lifestyle ·POINTER Imaging collected multimodal neuroimaging data in this unique, at-risk cohort ·Amyloid burden was related to age, apolipoprotein E (APOE) ε4 carriage, and measures of disease progression ·Associations between amyloid and tau, and tau and cognition, were relatively weak ·CVD risk and tau pathology were independently related to memory.

The Conversion of Ethanol to Syngas by Partial Oxidation in a Non-Premixed Moving Bed Reactor

An experimental investigation into the conversion of ethanol to syngas by partial oxidation in a non-premixed counterflow moving bed filtration combustion reactor was carried out. Regimes of conversion depending on the mass flow rates of fuel and air (separate feeding), as well as a granular solid heat carrier, were studied. Depending on the mass flow rate of the heat carrier, two combustion modes were realized—reaction trailing and intermediate—with different temperature patterns in the gas preheating, combustion, and cooling zones along the reactor. The product gas composition is far from the predictions of the equilibrium model; it contains substation fractions of methane and ethylene. Combustion temperature and conversion are limited by the relatively high level of heat loss from the laboratory-scale reactor. The effect of the heat loss can be reduced by enhancing the absolute flow rate of the reactants.

Nasal carriage of MRSA among clinically affiliated undergraduate students at the College of Health and Medical Sciences, Haramaya University, Ethiopia

Medical and health science students are among the demographics most at risk from Methicillin-resistant Staphylococcus aureus (MRSA), which is a serious hazard to public health. The main reservoir for MRSA is the nasal cavity, and colonization of this area can raise the risk of infection and transmission in healthcare settings. This study aimed to assess the nasal carriage rate of MRSA among clinically affiliated students at Haramaya University, College of Health and Medicine Sciences, Ethiopia, from July to August 2022. An institution-based cross-sectional study of 250 study participants was conducted using a stratified random sampling methods. The data were collected via structured questionnaires. Nasal swabs were cultured on mannitol salt agar and blood agar at 37 °C for 24 h. Staphylococcus aureus was identified using catalase and coagulase tests. The MRSA was screened using the cefoxitin disk diffusion method on Muller Hinton agar. The data were entered and analyzed by SPSS version 25. Pearson’s chi-square test was performed to predict associations between variables. A p value less than 0.05 was regarded as statistically significant. The nasal carriage rate of S. aureus was 8% (95% CI: 4.6-11.3%). The Nasal carriage rate of MRSA was 4.8% (95% CI: 2.1-7.4%). Overall, 4.8% of all the students were identified as MRSA carriers. MRSA carriage was high among medical students (33.3%). Nose-picking habit (X2 = 16.7, P = 0.001) and dormitory occupancy (X2 = 3.6, P = 0.045) were significantly associated with the MRSA rate. All the MRSA strains were resistant to penicillin and ampicillin. However, all the MRSA strains were susceptible to chloramphenicol and clindamycin. This study revealed that MRSA is a threat due to significant resistance. Nasal carriage is associated with nose picking and dorm occupancy. Encourage practices such as avoiding nose picking and maintaining personal cleanliness. Regular cleaning and disinfection of shared spaces can reduce the presence of MRSA.

Oral vancomycin use and incidence of vancomycin-resistant enterococci: time-series analysis

SummaryBackgroundVancomycin exposure is a major risk factor for vancomycin-resistant enterococci (VRE) colonisation, but the relationship between oral vancomycin and the risk of VRE colonisation remains poorly understood without ecological evidence. In this study, we investigated the association between oral vancomycin usage and the incidence of hospital-acquired VRE using a time-series analysis.MethodsThis retrospective ecological study analysed monthly data on antibiotic usage and VRE incidence from January 2013 to December 2022 at a 2700-bed hospital in South Korea. Antibiotic usage was measured in days of therapy (DOT) per 1000 patient-days. Hospital-acquired VRE incidence was defined as the number of VRE isolates identified more than 48 h after admission per 1000 patient-days. The association between oral vancomycin use and VRE incidence was assessed using a multivariate autoregressive integrated moving average (ARIMA) regression model incorporating lag structures.ResultsOver 10 years, 5,763 clinical VRE isolates were identified, with 5,133 (89%) being hospital-acquired. Oral vancomycin usage and VRE incidence showed significant upward trends during the study period. In the final ARIMA model adjusting for various types of antibiotic use and baseline VRE carriage rate, a significant association was observed between oral vancomycin use and VRE incidence (coefficient: 0.0160, 95% CI: 0.0030 to 0.0290, P = 0.0162), with an R-squared value of 0.76. Sensitivity analyses demonstrated the robustness of the association between oral vancomycin use and VRE acquisition across various time lags between antibiotic use and VRE incidence.ConclusionsThere was a significant association between institutional oral vancomycin use and hospital-acquired VRE incidence, highlighting the need for antibiotic stewardship for oral vancomycin use to contain the nosocomial spread of VRE in addition to infection control measures.