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Depression and anxiety connected with COVID- 19 crisis between nurse practitioners throughout India- A planned out assessment as well as meta-analysis.
Acid-alkaline balance plays a crucial role in all biological processes. Accordingly, monitoring pH changes will help us to understand the functional status of these physiological and pathological processes. Though fluorescent probes may be a useful tool for detecting pH changes, and there are many limitations to currently available probes, such as background interference, potential cytotoxicity, and poor cell permeability, which call for a solution urgently. In this work, a rhodamine-derived colorimetric and ratiometric sensor (Rh-HN) was fabricated for monitoring pH change via the mechanism of fluorescence resonance energy transfer (FRET). Rh-HN has been shown to possess several advantages over other probes, such as high sensitivity, outstanding permeability, and low toxicity. Besides, the fluorescence intensity ratio (F526/F592) of Rh-HN displays a pH-sensitive response from 2.0 to 7.5 (pKa = 5.05) and linear response from pH 3.8 to 6.4, which was desirable for mapping pH change in the biological systems. Besides, the results indicated that Rh-HN generated a pH-dependent response regulated by switchable forms between closed and opened spirolactam ring. Overall, Rh-HN has accomplished sensing and mapping of pH in living cells, bacteria, and zebrafish. Those results demonstrated that the great potential of Rh-HN in sensing and visualizing pH in the living biosystem.Coupling supercritical fluid extraction (SFE) on-line with supercritical fluid chromatography (SFC) - tandem mass spectrometry (MS/MS) provides a single platform for efficient extraction, separation, and detection in a chemical analysis. SFE-SFC-MS/MS requires consideration of many extraction and chromatographic variables to not only provide the most efficient extraction, but also to analytically transfer the extracted analytes to the column for separation. There is a fundamental lack of understanding of how the variables in SFE affect those in SFC. Typically, a univariate approach is taken in on-line SFE-SFC-MS/MS method development, but this provides little insight into the relative importance of variables and their potential interactions. Here, a multivariate approach was used to develop a better understanding of the synergistic relationship between the extraction and separation processes by focusing on the optimization of extraction parameters for target analytes with a wide range of physicochemical properties in matrices of variable retentivity. The methodology used a set of optimal on-line SFE-SFC-MS/MS extraction parameters for 18 analytes of variable physicochemical properties in three different silica gel-based sample matrices are presented.Current theoretical, two compartment description of integrative passive sampling is renewed to establish a three-compartment model. The developed theoretical description includes external chemical conditions near the receiving phase, conditions inside the receiving phase and the chemically bonded compartments. New variable p, which controls the chemical bonding process into the sampler receiving phase is introduced. This new theoretical model enables derivation of equations for accumulation of masses in situations where convective mass transfer coefficient (h) and chemically bonding activity (p) are defined as a piece-wise constant functions of time. Previous two compartment model, which connects time average external concentration and accumulated mass is derived directly to the case where h and p are constants during the whole observation period. For other situations more complex equation is derived. Applicability of new equations are tested in laboratory experiments with fluctuating external chemical concentration.Mercury speciation was achieved using a nanocomposite, consisting of graphene quantum dots (GQDs) and TiO2 nanoparticles, to mediate photo-degradation of mercurial species into the Hg cold vapor detected by atomic spectrometry. Sample solution (containing Hg2+, CH3CH2Hg, and CH3Hg at hundreds of ng L-1) was placed in quartz tube containing formic acid solution (2% v/v) and microliter aliquot of GQDs/TiO2 nanocomposite dispersion (0.6 mg of nanocomposite). selleckchem The tube was placed inside a photochemical reactor then, adapted to the mercury-dedicated spectrometer. Quantitative speciation was achieved taking advantage of the differences in UV photodegradation kinetics Hg2+ (5 min), CH3CH2Hg (9 min) and CH3Hg (13 min). Gas-chromatography cold vapor atomic fluorescence spectrometry was used to confirm the evolution of the reactions over time during photo-reaction. The limits of detection were 10 ng L-1 for CH3CH2Hg and 7 ng L-1 for Hg2+ and CH3Hg.Herein, sulfur vacancies in magnetic greigite (SVs-Fe3S4) nanosheets were synthesized by a one-step solvothermal method by adjusting the ethylene glycol water ratio. Electron paramagnetic resonance spectroscopy (EPR) and X-ray photoelectron spectroscopy (XPS) revealed that SV-rich Fe3S4 and SV-poor Fe3S4 were acquired using 100% ethylene glycol and 100% water as solvent, respectively. A peroxidase-like activity assay demonstrated that maximum reaction rates for H2O2-mediated oxidation of 3,3',5,5'-tetramethyl-benzidine (TMB) catalyzed by the SV-rich Fe3S4 was 2.3 times higher than SV-poor Fe3S4. Density functional theory (DFT) calculations and reactive oxygen species (ROS) detection confirmed that the enhanced peroxidase-like activity by SV-rich Fe3S4 was attributed to efficient adsorption of H2O2 and subsequent decomposition to hydroxyl radicals (•OH) on the SVs sites of Fe3S4. The SV-rich Fe3S4 nanozyme was employed to develop a simple, highly sensitive and selective assay for glucose detection with a linear range of 0.5-150 μM and a detection limit of 0.1 μM (S/N = 3). A smartphone application (App) was designed and applied to efficiently detect serum glucose with the integrated analytical system based on the SV-rich Fe3S4. These new findings highlight the important role of surface defects in nanozymes on generating peroxidase-like activity for glucose detection in point-of-care diagnosis.It is a big challenge to isolate extracellular vesicles (EVs) from human plasma because of the contamination from high abundant lipoproteins, such as high density lipoprotein (HDL) and low density lipoprotein particles (LDL). In this study, the parameters of asymmetrical flow field-flow fractionation (AF4) technology and sample preparation, including cross flow gradient, focusing time, ultrafiltration condition, sample amount and injection volume have been optimized and successfully utilized for the separation and characterization of EVs from human plasma. This study demonstrated that the great potential of AF4 in the separation of EVs from HDL and LDL in human plasma with high reproducibility and purity. This study indicated excessive focusing time in the AF4 separation and 100-300 kDa MWCO membrane based ultrafiltration in the pre-preparation will cause loss of EVs. A total of 1038 proteins have been identified in seven replicates of purified EVs from pooled human plasma sample. They are mainly enriched in extracellular exosomes, involved in extracellular matrix structural constituent, and associated with extracellular matrix-receptor interaction pathway. This study also indicated that human plasma contains more EVs than the paired serum at the same volume, and showed age- and gender-independent individual variability of the amount of EVs in human plasma. This study displayed that AF4 technique can serve as a powerful platform for the separation of EVs from human plasma, serum or human body fluids and this technology will promote the studies on EVs, such as proteomics, biomarker discovery and functions.The severity of foodborne diseases caused by foods contaminated by pathogens or their toxins creates an urgent need for the development of specific and sensitive method for detection of bacteria. In this study, taking advantages of CRISPR-Cas13a system, namely, the crRNA programmability and Cas13a "collateral effect" of promiscuous RNase activity upon target RNA recognition, we developed a bacterial sensing strategy with the name of CCB-Detection (CRISPR-Cas13a based Bacterial Detection). Staphylococcus aureus (S. aureus) was chosen as a model bacteria for validating the performance of CCB-Detection. Specifically, four steps were carried out 1) simple extraction of genome DNA; 2) specific gene amplification by PCR; 3) in vitro transcription; and 4) the "collateral effect" cleavage of reporter RNA to report the analyte signal. It was observed that CCB-Detection was capable to successfully detect the target genomic DNA (gDNA) as low as 100 aM. The limit of detection (LOD) was 1 CFU/mL with a dynamic detection range of S. aureus from 100 to 107 CFU/mL. The entire sample-to-answer time for this biosensor was less than 4 h. CCB-Detection demonstrated satisfactory selectivity for S. aureus without interference from other bacteria. Furthermore, CCB-Detection was successfully applied for sensing S. aureus in real food samples with both known and unknown amounts bacteria (spiked ones and non-spiked ones) and its performance is comparable to the conventional culture-based counting method but with short assay time and high sensitivity. With desirable reliability, sensitivity, specificity and simplicity, herein proposed CCB-Detection could be extended and generalised for other bacterial detection, and has great potential to be used in a wide range of applications such as food safety inspection, disease diagnosis, environment monitoring, etc.In this study, an isothermal paper biosensor, combining single universal primer recombinase polymerase amplification (SUP-RPA) and the lateral flow technique was developed for the multiplex detection of genetically modified maize (GMM). In pre-amplification stage, the event-specific primers contain a universal sequence at the 5' end, with a biotin-labeled deoxycytidine triphosphate (dCTP) deoxynucleotide providing additional amplification, which improves their amplification ability and ensures consistent multiplex amplification efficiency. In the signal recognition strategy, the SUP-RPA products are identified visually using the lateral flow biosensor (LFB) through dual hybridization. The accumulation of gold nanoparticles (AuNPs) produces a characteristic red band. Through this biosensor, a limit of detection of at least 50 copies was achieved, which is sensitive enough to detect MON810, MON863 and MON89034 simultaneously. The entire process of analysis was completed within 30 min and without any large-scale instrumentation. This biosensor, therefore, provides a novel rapid and portable multiple detection method for point-of-care applications, especially genetically modified organism (GMO) event-specific detection.Antimicrobial stewardship practices are critical in preventing the further erosion of treatment options for bacterial infections. Yet, at the same time, determination of an infection's antimicrobial susceptibility requires multiple rounds of culture and expensive lab automation systems. In this work, we report the use of paper-based surface enhanced Raman spectroscopy (SERS) sensors and portable instrumentation to phenotypically discriminate multi-drug resistance with fewer culture steps than conventional clinical microbiology. Specifically, we demonstrate the identification of resistance to varying generations of β-lactam antibiotics by detecting the activity of particular β-lactamase enzymes in a multiplexed assay. The method utilizes molecular reporters that consist of β-lactams with SERS barcodes. Hydrolysis of the β-lactam by β-lactamase enzymes in the sample expels the barcode; the released sulfur-containing barcode is then detected via SERS. Using this approach, we demonstrate the differentiation of E.
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