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Buffer-specific effects arise from ionic dispersion forces
No full textBuffer solutions do not simply regulate pH, but also change the properties of protein molecules. The zeta potential of lysozyme varies significantly at the same buffer concentration, in the order Tris > phosphate > citrate, with citrate even inverting the zeta potential, usually positive at pH 7.15, to a negative value. This buffer-specific effect is a special case of the Hofmeister effect. Here we present a theoretical model of these buffer-specific effects using a Poisson–Boltzmann description of the buffer solution, modified to include dispersion forces of all ions interacting with the lysozyme surface. Dispersion coefficients are determined from quantum chemical polarizabilites calculated for each ion for tris, phosphate, and citrate buffer solutions. The lysozyme surface charge is controlled by charge regulation of carboxylate and amine sites of the component amino acids. The theoretical model satisfactorily reproduces experimental zeta potentials, including change of sign with citrate, when hydration of small cosmotropic ions (Na+, H+, OH−) is included
Risk analysis of 24 residual antibiotics in poultry eggs in Shandong, China (2018–2020)
No full textAlthough antibiotics have played a certain positive role in the prevention and treatment of poultry diseases, as well as the promotion of poultry growth, some farmers use antibiotics in an incorrect way in the breeding process, resulting in antibiotic residues in poultry tissues, organs and edible products. Residual antibiotics enter the human body through the food chain and accumulate, which not only causes poisoning and allergic reactions, but also drug resistance of pathogenic microorganisms, thus endangering the health of consumers. In this investigation, the residues of 24 antibiotics, including fluoroquinolones, sulfonamides, macrolides, tetracyclines, antivirals, lincomycin and florfenicol, were analyzed in 1211 poultry egg samples in Shandong, China, from 2018 to 2020. Then, based on the per capita intake of poultry eggs recommended in the dietary guidelines of Chinese residents, the maximum residue limit of veterinary drugs specified in Chinese regulations and the average weight of males and females aged 18 and over in 2020, the risk of residual antibiotics was evaluated by International Food Safety indices (IFS). The detection results showed that 104 of 1211 samples were detected with antibiotic residues, with a detection rate of 8.58%. Among them, the main residues were enrofloxacin, sulfonamides and florfenicol. The IFS calculation results showed that the IFS of residual antibiotics ranged from 1.44 × 10−7 to 0.102. Therefore, although enrofloxacin, sarafloxacin, danofloxacin, sulfonamides, tilmicosin, doxycycline, florfenicol, which are banned during egg laying, were detected in poultry eggs in Shandong, these residues did not pose a threat to the health of Chinese adult consumers, according to the daily dietary habits of Chinese people. However, it is strongly suggested that Shandong should strengthen the monitoring of antibiotic use during egg laying
Electro-driven materials and processes for lithium recovery—A review
Get PDFThe mass production of lithium-ion batteries and lithium-rich e-products that are required for electric vehicles, energy storage devices, and cloud-connected electronics is driving an unprecedented demand for lithium resources. Current lithium production technologies, in which extraction and purification are typically achieved by hydrometallurgical routes, possess strong environmental impact but are also energy-intensive and require extensive operational capabilities. The emergence of selective membrane materials and associated electro-processes offers an avenue to reduce these energy and cost penalties and create more sustainable lithium production approaches. In this review, lithium recovery technologies are discussed considering the origin of the lithium, which can be primary sources such as minerals and brines or e-waste sources generated from recycling of batteries and other e-products. The relevance of electro-membrane processes for selective lithium recovery is discussed as well as the potential and shortfalls of current electro-membrane methods
Global evolutionary dynamics and resistome analysis of Clostridioides difficile ribotype 017
Get PDFClostridioides difficile PCR ribotype (RT) 017 ranks among the most successful strains of C. difficile in the world. In the past three decades, it has caused outbreaks on four continents, more than other ‘epidemic’ strains, but our understanding of the genomic epidemiology underpinning the spread of C. difficile RT 017 is limited. Here, we performed high-resolution phylogenomic and Bayesian evolutionary analyses on an updated and more representative dataset of 282 non-clonal C. difficile RT 017 isolates collected worldwide between 1981 and 2019. These analyses place an estimated time of global dissemination between 1953 and 1983 and identified the acquisition of the ermB-positive transposon Tn6194 as a key factor behind global emergence. This coincided with the introduction of clindamycin, a key inciter of C. difficile infection, into clinical practice in the 1960s. Based on the genomic data alone, the origin of C. difficile RT 017 could not be determined; however, geographical data and records of population movement suggest that C. difficile RT 017 had been moving between Asia and Europe since the Middle Ages and was later transported to North America around 1860 (95 % confidence interval: 1622–1954). A focused epidemiological study of 45 clinical C. difficile RT 017 genomes from a cluster in a tertiary hospital in Thailand revealed that the population consisted of two groups of multidrug-resistant (MDR) C. difficile RT 017 and a group of early, non-MDR C. difficile RT 017. The significant genomic diversity within each MDR group suggests that although they were all isolated from hospitalized patients, there was probably a reservoir of C. difficile RT 017 in the community that contributed to the spread of this pathogen
How have COVID‐19 stringency measures changed scholarly activity?
Get PDFGovernment restrictions to the movement of people due to the COVID-19 pandemic have had a wide range of effects on scientific activity. Here, we show that during the pandemic there has been a reduction in the number of registered non-COVID-19 clinical trials. Furthermore, using the Oxford COVID-19 Government Response Tracker Stringency Index (SI) as an indicator of COVID-19–related workplace adjustment (e.g., restrictions on gatherings, workplace closures, and stay-at-home orders), we demonstrate that this drop in clinical trial registration has been greater in countries with a higher SI. This could have significant consequences for the discovery of treatments that are required to reduce the global burden of disease
We're on mute! Exclusion of nurses' voices in national decisions and responses to COVID ‐19: An international perspective
No full textNurses are the largest healthcare workforce and have had direct, intense and sustained contact with COVID-19 patients throughout the pandemic playing an essential and frontline role in the COVID-19 response. Nurses have worked tirelessly and undertaken multiple roles during the pandemic including education, treatment, prevention, vaccination and research often in uncertain situations and to the detriment of their physical and mental health. They have also managed and cared for distressed patients and their families, and many have been redeployed to other roles often outside of their usual duties, all factors which have affected their well-being. They have publicly been lauded as ‘heroes’. Yet, their voices and perspectives are seldom heard or included in COVID-19 decision-making and in the development of interventions and responses at all levels from individual health services to national policymaking. Indeed, it has felt like these voices have been muted and excluded. Nurses' unique knowledge, expertise, needs and lived experiences are vital to the COVID-19 response. Without their inclusion, COVID-19 decision-making and initiatives are unlikely to be successful and patient outcomes poorer
Clostridioides difficile infection in Africa: A narrative review
No full textClostridioides (Clostridium) difficile infection (CDI) places a burden on healthcare facilities worldwide. Most research studies have been concentrated in high-income countries in North America, Europe, Asia and Australia, where C. difficile is the leading cause of diarrhoea associated with antimicrobial use. This narrative review summarises African CDI studies, focussing on reports published in the last 20 years. Although relatively sparse, the data suggest that CDI is an important cause of diarrhoea on the continent. African CDI patient populations are often younger than in European and North American settings, probably due to the high prevalence of co-morbid conditions such as tuberculosis, particularly in sub-Saharan Africa. Strain typing data are rare and where reported generally limited to single sites and institutions. Despite challenges, including a lack of facilities and awareness, there is a need for further investigation to more accurately determine the true burden of disease caused by C. difficile in Africa
Antimicrobial resistance and genomic relationships of Salmonella enterica from Australian cattle
No full textThe aim of this study was to evaluate phenotypic and genotypic AMR characteristics of Salmonella enterica isolates from Australian cattle collected through a structured national survey utilizing 1001 faecal samples collected from healthy cattle at slaughter. A total of 184 Salmonella isolates were subsequently derived and subjected to microbroth dilution to 16 drugs from 11 classes with interpretation of minimum inhibitory concentrations (MICs) using epidemiological cut off (ECOFF) values to distinguish between wild-type and non-wild-type populations. Most isolates were susceptible (wild type) to all antimicrobials tested, with no resistance (non-wild type) detected for colistin, nalidixic acid, meropenem, gentamicin, florfenicol or chloramphenicol. Low rates of resistance were detected for ampicillin (2.2%), cefoxitin (2.2%), ceftiofur (2.2%), ceftriaxone (2.2%), ciprofloxacin (0.5%), streptomycin (3.3%) and tetracycline (0.5%). Isolates resistant to ceftriaxone (a critically important antimicrobial, CIA) carried the extended spectrum cephalosporin gene blaCMY-2 while no known mutation in the QRDR region or qnrS genes were detected for the CIA ciprofloxacin-resistant isolate. Thirty-six serovars were detected among the 184 Salmonella isolates using whole genome sequencing, dominated by Typhimurium (n = 36), Saintpaul (n = 22) and Anatum (n = 16). Genomic analysis clustered the cattle isolates based on serovar, with the majority of serovars containing a single sequence type (ST). Further analysis of the bovine Typhimurium isolates (ST19) and comparison with publicly available data from human Typhimurium isolates from Australia, revealed the majority of cattle isolates were unrelated to human isolates. In conclusion, this study demonstrates the continued low prevalence of AMR among Salmonella within the beef, dairy and veal industries in Australia. Salmonella Typhimurium from cattle were genetically distinct from isolates sourced from human infections. Further investigations are warranted to expand on the potential clinical and public health relevance of these findings to inform risk-management of this key pathogen
Affective-cognitive-behavioral heterogeneity of Attention-Deficit/Hyperactivity Disorder (ADHD): Emotional dysregulation as a sentinel symptom differentiating “ADHD-simplex” and “ADHD-complex” syndromes?
No full textBackground
Current DSM and ICD classifications of Attention-Deficit/Hyperactivity Disorder (ADHD) exclude emotional dysregulation (ED) in their diagnostic criteria, despite ED symptoms frequently co-occurring in ADHD and likely sharing common neurobiological substrates. In this study, we examined whether consideration of ED symptoms could delineate more informative “ADHD+ED” subphenotypes.
Method
4106 children with ADHD were recruited. ED and inattentive (IA) and hyperactive/impulsive (HI) symptoms were profiled using latent class analyses (LCA). The derived latent class (LC) subphenotypes were evaluated and validated in relation to comorbidity patterns, executive functions, and functional impairments.
Results
Five LC subphenotypes with ED symptoms were identified: IA/HI + ED profile (LC1); HI + ED profile (LC2); IA + ED profile (LC3); IA/HI profile (LC4); and IA profile (LC5). Cross-validation of the LCA model using support vector machine analysis confirmed 83% accuracy. ED positive (ED+ve) subphenotypes were associated with higher rates of oppositional defiant disorder, mood disorders, anxiety disorders, as well as more severe autistic traits and sluggish cognitive tempo symptoms. Higher rates of ecological executive functioning impairments (BRIEF ratings) were found among ED+ve subphenotypes (though no differences were detected by laboratory-based measures). Functional impairments were also more severe among participants with ED+ve subphenotypes.
Limitations
The data for our LCA were cross-sectional and based primarily on parent ratings.
Conclusion
Our classification model has parcellated IA, HI, and ED symptoms into novel informative subphenotypes. These classifications provide preliminary evidence that ED symptoms could serve as sentinel features to identify a potential “ADHD-complex” syndrome, which demarcates a more pervasive condition of greater severity, complexity, and impairment