The use of natural compounds from plants can provide an alternative approach against food-borne pathogens. The mechanisms of action of most plant extracts with antimicrobial activity have been poorly ...studied. In this work, changes in membrane integrity, membrane potential, internal pH (pHin), and ATP synthesis were measured in Vibrio cholerae cells after exposure to extracts of edible and medicinal plants. A preliminary screen of methanolic, ethanolic, and aqueous extracts of medicinal and edible plants was performed. Minimal bactericidal concentrations (MBCs) were measured for extracts showing high antimicrobial activity. Our results indicate that methanolic extracts of basil (Ocimum basilicum L.), nopal cactus (Opuntia ficus-indica var. Villanueva L.), sweet acacia (Acacia farnesiana L.), and white sagebrush (Artemisia ludoviciana Nutt.) are the most active against V. cholera, with MBCs ranging from 0.5 to 3.0 mg/ml. Using four fluorogenic techniques, we studied the membrane integrity of V. cholerae cells after exposure to these four extracts. Extracts from these plants were able to disrupt the cell membranes of V. cholerae cells, causing increased membrane permeability, a clear decrease in cytoplasmic pH, cell membrane hyperpolarization, and a decrease in cellular ATP concentration in all strains tested. These four plant extracts could be studied as future alternatives to control V. cholerae contamination in foods and the diseases associated with this microorganism.
When this AJPH special section on rural health is published, the United States as a nation, the individual states, local communities, and US citizens will still be addressing and be affected by the ...COVID-19 (coronavirus disease 2019) pandemic, which will have resulted in more than two million cases of COVID-19-the disease caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2)-and more than 115 000 deaths in the United States. The pandemic has made obvious the importance and value ofa competent, adequately resourced public health system and competent, adequately resourced hospital care, particularly critical care. The pandemic has also exposed the weaknesses and fragmented nature of the public health system and infrastructure in the United States and the medical care delivery system and infrastructure, which should, but do not, function as virtually one unified health system.
Vanadium compounds have been primarily investigated as potential therapeutic agents for the treatment of various major health issues, including cancer, atherosclerosis, and diabetes. The translation ...of vanadium-based compounds into clinical trials and ultimately into disease treatments remains hampered by the absence of a basic pharmacological and metabolic comprehension of such compounds. In this review, we examine the development of vanadium-containing compounds in biological systems regarding the role of the physiological environment, dosage, intracellular interactions, metabolic transformations, modulation of signaling pathways, toxicology, and transport and tissue distribution as well as therapeutic implications. From our point of view, the toxicological and pharmacological aspects in animal models and humans are not understood completely, and thus, we introduced them in a physiological environment and dosage context. Different transport proteins in blood plasma and mechanistic transport determinants are discussed. Furthermore, an overview of different vanadium species and the role of physiological factors (i.e., pH, redox conditions, concentration, and so on) are considered. Mechanistic specifications about different signaling pathways are discussed, particularly the phosphatases and kinases that are modulated dynamically by vanadium compounds because until now, the focus only has been on protein tyrosine phosphatase 1B as a vanadium target. Particular emphasis is laid on the therapeutic ability of vanadium-based compounds and their role for the treatment of diabetes mellitus, specifically on that of vanadate- and polioxovanadate-containing compounds. We aim at shedding light on the prevailing gaps between primary scientific data and information from animal models and human studies.
Encouraged by the diversity of n-dodecane chemical mechanisms currently available, this investigation focuses on analysing the impact of using different fuel oxidation schemes on the diesel-like ...Engine Combustion Network (ECN) Spray A flame structure, simulated by means of an Unsteady Flamelet Progress Variable (UFPV) combustion model. The present research discusses systematically the characteristics of four n-dodecane chemical mechanisms in perfectly stirred reactors and counterflow laminar diffusion flames (flamelets) before the final evaluation in turbulent reacting sprays in order to describe the effects of adding different physical levels of complexity to the ignition of the mixtures. In addition, this analysis is complemented with the description of the effect of the boundary conditions on the flame structure.
Results evidence the extreme importance of the low temperature chemistry including the period for which the cool flame extends. The different prediction of this stage between mechanisms leads to noticeable different laminar flame structures which in turn produce substantially distinct turbulent flames, especially in the vicinity of the lift-off length (LOL) in terms of reactivity and positioning in the Z-T map. Finally, simulations confirm the strong effect of the boundary conditions, especially for the ambient temperature, on the ignitable mixtures which directly impacts on the soot precursors formation.
Structural racism has been and remains a fundamental cause of persistent health disparities in the United States. The coronavirus disease 2019 (COVID-19) pandemic and the police killings of George ...Floyd, Breonna Taylor, and multiple others have been reminders that structural racism persists and restricts the opportunities for long, healthy lives of Black Americans and other historically disenfranchised groups. The American Heart Association has previously published statements addressing cardiovascular and cerebrovascular risk and disparities among racial and ethnic groups in the United States, but these statements have not adequately recognized structural racism as a fundamental cause of poor health and disparities in cardiovascular disease. This presidential advisory reviews the historical context, current state, and potential solutions to address structural racism in our country. Several principles emerge from our reviewracism persists; racism is experienced; and the task of dismantling racism must belong to all of society. It cannot be accomplished by affected individuals alone. The path forward requires our commitment to transforming the conditions of historically marginalized communities, improving the quality of housing and neighborhood environments of these populations, advocating for policies that eliminate inequities in access to economic opportunities, quality education, and health care, and enhancing allyship among racial and ethnic groups. Future research on racism must be accelerated and should investigate the joint effects of multiple domains of racism (structural, interpersonal, cultural, anti-Black). The American Heart Association must look internally to correct its own shortcomings and advance antiracist policies and practices regarding science, public and professional education, and advocacy. With this advisory, the American Heart Association declares its unequivocal support of antiracist principles.
In the last years, many researchers have proposed improvements to the minimum quantity lubrication (MQL) technique, in order to increase its efficiency and make it a viable alternative to the ...conventional application of cutting fluids for a cleaner machining. Besides the lubri-cooling effect inherent to the MQL technique, the cleaning of grinding wheel is pursued, since its surface undergoes the clogging phenomenon resulting in decreasing of the process performance. The main objective of this study is to assess the influence of the auxiliary wheel cleaning jet (WCJ) in an attempt to reduce the wheel clogging phenomenon and increase lubri-cooling and machining efficiencies in the cylindrical external grinding of AISI 4340 steel under the application of the MQL technique using aluminum oxide grinding wheel. The MQL combined with cleaning jet was compared to both flood application (conventional) and MQL without WCJ (traditional). MQL grinding employed oil flow rates of 30, 60 and 120 mL/h in order to evaluate the effects of amount of grinding fluid in the assessment. The conventional and MQL + WCJ methods produced lower surface roughness and roundness deviation compared to the other methods used due to the fact that they kept the wheel sharpness longer. Moreover, conventional and MQL + WCJ methods increased G ratio and reduced tangential grinding forces and specific energy in comparison to traditional MQL. The MQL + WCJ method enabled the removal of part of chips adhered on the grinding wheel active surface (GWAS) when compared to the traditional MQL, reducing the wheel clogging, which is one of the reasons for loss of wheel sharpness. Tubular chip form occurred not only in MQL + WCJ grinding but also in traditional MQL grinding, although it is not mentioned in literature.
The discovery and tracking of antimicrobial resistance genes are essential for understanding the evolution of bacterial resistance and restraining its dispersion. Mammaliicoccus sciuri (formerly ...Staphylococcus sciuri) is the most probable evolutionary repository of the mecA gene, that later disseminated to S. aureus. In this study, we describe the first double mecA/mecC homologue-positive non-aureus staphylococci and mammaliicocci (NASM) from the American continent, also representing the first report of mecC-positive NASM in Brazil. Two clonally related methicillin-resistant M. sciuri strains co-carrying mecA and mecC genes were isolated from the teat skin swab and milk sample collected from an ewe’s left udder half. Both M. sciuri strains belonged to the sequence type (ST) 71. Besides mecA and mecC genes, the M. sciuri strains carried broad resistomes for clinically important antimicrobial agents, including β-lactams, tetracyclines, lincosamide, streptogramin, streptomycin, and aminoglycosides. Virulome analysis showed the presence of the clumping factor B (clfB), ATP-dependent protease ClpP (ClpP) and serine-aspartate repeat proteins (sdrC and sdrE) virulence-associated genes. Phylogenomic analysis revealed that these M. sciuri strains are part of a globally disseminated branch, associated with farm and companion animals and even with food. Our findings suggest that M. sciuri is likely to emerge as a pathogen of global interest, carrying a broad repertoire of antimicrobial resistance genes with a remarkable co-presence of mecA and mecC genes. Finally, we strongly encourage to monitor M. sciuri under the One Health umbrella since this bacterial species is spreading at the human-animal-environment interface.
•Genomic study of Mammaliicoccus sciuri strains co-harboring mecA and mecC genes.•The presence of broad resistomes and virulence-associated genes was confirmed.•Phylogenomic analysis showed clonal relatedness with strains from Asia and Europe.•Clonal similarity with strains from domestic animals and food is demonstrated.•Human-animal-environment interface spread of M. sciuri mec-type genes is discussed.
Solid‐state lithium metal (Li°) batteries (SSLMBs) are believed to be the most promising technologies to tackle the safety concerns and the insufficient energy density encountered in conventional ...Li‐ion batteries. Solid polymer electrolytes (SPEs) inherently own good processability and flexibility, enabling large‐scale preparation of SSLMBs. To minimize the growth of Li° dendrites and cell polarization in SPE‐based SSLMBs, an additive‐containing single Li‐ion conductive SPE is reported. The characterization results show that a small dose of electrolyte additive (2 wt%) substantially increases the ionic conductivity of single Li‐ion conductive SPEs as well as the interfacial compatibility between electrode and SPE, allowing the cycling of SPE‐based cells with good electrochemical performance. This work may provide a paradigm shift on the design of highly cationic conductive electrolytes, which are essential for developing safe and high‐performance rechargeable batteries.
A small dose of electrolyte additive in a single Li‐ion conductive solid polymer electrolyte remarkably increases the Li‐ion conductivity and the interfacial stability against electrodes, endowing Li metal || LiFePO4 cells with good cycling performance. Role‐specified electrolyte additives are believed to be powerful tools for attaining high‐performance rechargeable solid‐state lithium batteries.
The anion chemistry of lithium salts plays a pivotal role in dictating the physicochemical and electrochemical performance of solid polymer electrolytes (SPEs), thus affecting the cyclability of ...all‐solid‐state lithium metal batteries (ASSLMBs). The bis(trifluoromethanesulfonyl)imide anion (TFSI−) has long been studied as the most promising candidate for SPEs; however, the Li‐ion conductivities of the TFSI‐based SPEs still remain low (Li‐ion transference number: ca. 0.2). In this work, we report new hydrogen‐containing anions, conceived based on theoretical considerations, as an electrolyte salt for SPEs. SPEs comprising hydrogen‐containing anions achieve higher Li‐ion conductivities than TFSI‐based ones, and those anions are electrochemically stable for various kinds of ASSLMBs (Li–LiFePO4, Li–S, and Li–O2 batteries). This opens up a new avenue for designing safe and high‐performance ASSLMBs in the future.
Substituted for success: A selective introduction of hydrogen into sulfonimide anions can improve the Li‐ion conductivity of polymer electrolytes by their interaction with the polymer matrices. This makes them promising building blocks for high‐performance all‐solid‐state lithium metal batteries.
PDF
