29,202 results match your criteria time-of-flight mass

Untargeted flavor profiling of lager beers by stir bar sorptive extraction -capillary gas chromatography - time-of-flight mass spectrometry: High analytical performance with a green touch.

J Chromatogr A 2021 Apr 28;1647:462164. Epub 2021 Apr 28.

Research Institute for Chromatography (RIC), Pres. Kennedypark 26, B-8500 Kortrijk, Belgium.

Beer is one of the most popular beverages in the world and its complex flavor is widely appreciated. Beer flavor profiling is important for brewers to optimize beer production and to guarantee odor quality and taste stability of the final products. This is especially the case for pale lager beers that represent the beer type with the largest worldwide production volume. Read More

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Optical Limiting Applications of Resonating Plasmonic Au Nanoparticles in a Dielectric Glass Medium.

Nanotechnology 2021 May 7. Epub 2021 May 7.

Department of Physics, University of the Free State, PO Box 339, ZA -9300 Bloemfontein, Bloemfontein, SOUTH AFRICA.

Plasmonic nanostructures exhibiting high optical nonlinearities are widely used in the rapidly growing modern nanotechnology of nonlinear optics including biomedical applications due to their tunable plasmonic behavior. In this work, we investigate the nonlinear optical properties of uniformly distributed Au nanoparticles (NPs) embedded in pre-synthesized sodium-zinc borate glass by the well-known ion-exchange technique for optical limiting (OL) applications. Various techniques such as optical absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), Transmission Electron Microscope (TEM), Photoluminescence, Time of Flight secondary mass spectroscopy and the Z scan technique were used for the characterization of these NPs. Read More

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Photooxidative decomposition and defluorination of perfluorooctanoic acid (PFOA) using an innovative technology of UV-vis/ZnCuFeO/oxalic acid.

Chemosphere 2021 Apr 27;280:130660. Epub 2021 Apr 27.

Water Infrastructure Division, Center for Environmental Solutions and Emergency Response, U. S. EPA, 26 West Martin Luther King Drive, Cincinnati, OH, 45268, USA. Electronic address:

Per- and polyfluoroalkyl substances (PFAS) are a large group of perfluorinated organic molecules that have been in use since the 1940s for industrial, commercial, and consumer applications. PFAS are a growing concern because some of them have shown persistent, bioaccumulative and toxic effects. Herein, we demonstrate an innovative technology of UV-vis/ZnCuFeO/oxalic acid for the degradation of perfluorooctanoic acid (PFOA) in water. Read More

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Comparative evaluation of the Bruker Biotyper and Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems for non-albicans Candida and uncommon yeast isolates.

J Microbiol Methods 2021 May 4:106232. Epub 2021 May 4.

University of Health Sciences, Sisli Etfal Training and Research Hospital, Turkey.

Introduction: Rapid and accurate diagnosis is critically important in invasive and disseminated fungal infections for appropriate antifungal treatment.

Hypothesis: MALDI-TOF MS systems are effective for fast and accurate identification of Candida species.

Aim: We aimed to compare two MALDI-TOF MS systems for the rapid identification of non-albicans Candida and rare clinical yeast species. Read More

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Photodegradation of α-Pinene Secondary Organic Aerosol Dominated by Moderately Oxidized Molecules.

Environ Sci Technol 2021 May 7. Epub 2021 May 7.

Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland.

Atmospheric secondary organic aerosol (SOA) undergoes chemical and physical changes when exposed to UV radiation, affecting the atmospheric lifetime of the involved molecules. However, these photolytic processes remain poorly constrained. Here, we present a study aimed at characterizing, at a molecular level and in real time, the chemical composition of α-pinene SOA exposed to UV-A light at 50% relative humidity in an atmospheric simulation chamber. Read More

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Mycetoma due to Treated Successfully with Cotrimoxazole and Moxifloxacin.

Indian Dermatol Online J 2021 Mar-Apr;12(2):298-301. Epub 2021 Feb 22.

Department of Microbiology, Safdarjung Hospital and Vardhaman Mahavir Medical College, Ansari Nagar, New Delhi, India.

is a recently identified organism and has rarely been reported to cause mycetoma. Here we report the case of a 40-year-old woman who presented with discharging sinuses and nodules for the past 7 years along with few discrete axillary lymph nodes. Cultures and Maldi-TOF MS (Matrix-assisted laser desorption/ionization-time of flight mass spectrometry) method identified the causative organism as The organism was acid-fast positive on modified Ziehl-Neelsen stain and Gram's stain revealed branched filamentous beaded gram-positive bacilli, while histopathology showed granulation tissue along with few ill-defined epithelioid cell granulomas, with giant cells. Read More

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February 2021

Determination and dietary risk assessment of 284 pesticide residues in local fruit cultivars in Shanghai, China.

Sci Rep 2021 May 6;11(1):9681. Epub 2021 May 6.

Institute for Agro-Food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1000 Jinqi Road, Shanghai, 201403, China.

The presence of pesticide residues has become one of the main risk factors affecting the safety and quality of agro-food. In this study, a multi-residue method for the analysis of 284 pesticides in five local fruit cultivars in Shanghai was developed based on ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). The limits of determination and the limits of quantitation of pesticides were 0. Read More

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Laboratory-based evaluation of a simplified point-of-care test intended to support treatment decisions in non-severe bovine clinical mastitis.

J Dairy Res 2021 May 7:1-6. Epub 2021 May 7.

Scottish Centre for Production Animal Health and Food Safety, School of Veterinary Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Bearsden Road, GlasgowG61 1QH, UK.

To limit the use of antimicrobials in dairy cattle, farmers are increasingly encouraged to adopt targeted treatment decisions based on knowledge of the pathogens causing clinical mastitis (CM), whereby treatment of non-severe CM is generally recommended for gram-positive mastitis but not for gram-negative or culture-negative mastitis. The objectives of this study were to conduct a laboratory-based evaluation of the performance of a simplified slide test as a tool to differentiate gram-positive CM from other cases of CM, and to compare its performance against a commercially available on-farm test that is commonly used in our area (VétoRapid). Test outcomes after 24-48 h incubation were compared to results from bacteriological culture and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS). Read More

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Integrating transcriptome and metabolome analyses of the response to cold stress in pumpkin (Cucurbita maxima).

PLoS One 2021 6;16(5):e0249108. Epub 2021 May 6.

Qingdao Institute of Agricultural Science Research, Qingdao, Shandong, China.

Cucurbita maxima belong to the genus Cucurbita and are of nutritional and economic importance. Physiological activity, transcriptome, and metabolome analyses of leaf samples from the C. maxima inbreding line IL7 treated at 5 °C and 25 °C were performed. Read More

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Prevalence and Characterization of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae in Major Hospitals in Gabon.

Microb Drug Resist 2021 May 5. Epub 2021 May 5.

Laboratoire de Bactériologie, Centre Hospitalier Universitaire de Montpellier, Montpellier, France.

In Gabon, few data exist on extended-spectrum beta-lactamases-producing Enterobacteriaceae (ESBL-PE). This study investigated ESBL-PE prevalence and the associated resistance genes in clinical samples ( = 5,956) and anal swabs ( = 78) analyzed in eight hospitals and a medical analysis laboratory in Gabon from January 2016 to March 2018. Matrix-Assisted Laser Desorption Ionization-Time Of Flight (MALDI-TOF) mass spectrometry analysis identified 790 Enterobacteriaceae isolates ( = 712 clinical samples and  = 78 fecal samples). Read More

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High oxide-ion conductivity in acceptor-doped Bi-based perovskites at modest doping levels.

Phys Chem Chem Phys 2021 May 6. Epub 2021 May 6.

Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD, UK.

A combination of impedance spectroscopy, time-of-flight secondary ion mass spectrometry and literature data are used to show that, (i) the bulk oxide ion conductivity of A-site, alkaline earth-doped BiFeO3 (BF) is independent of the ionic radius of the alkaline earth ion (Ca, Sr, Ba) and, (ii) despite very different A-site environments in (Na1/2Bi1/2)TiO3 and BF, similar high levels and optimisation of bulk oxide ion conductivity in these Bi-based tilted perovskites is achieved at modest acceptor doping levels of ∼1-10%. These results clearly demonstrate that optimisation of oxide ion conductivity in these materials requires concepts beyond a simple crystallochemical approach based on matching the ionic radii of acceptor dopant and host lattice ions. Read More

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A novel (ATC) microsatellite locus is associated with litter size in an indigenous Chinese pig.

Vet Med Sci 2021 May 6. Epub 2021 May 6.

Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining, China.

Simple sequence repeats (SSRs) are an important part of the genome and have become powerful auxiliary DNA markers in animal breeding using marker-assisted selection (MAS). Based on previous sequencing data of Qinghai Bamei pigs, a total of three novel candidate SSR loci were analysed in this study. Time-of-flight mass spectrometry (TOF-MS) was used for SSR genotyping, and association analyses between SSRs and the litter size of Qinghai Bamei sows was also performed. Read More

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Negative-mode mass spectrometry in the analysis of invertebrate, fungal, and protist N-glycans.

Mass Spectrom Rev 2021 May 6. Epub 2021 May 6.

Department für Chemie, Universität für Bodenkultur Wien, Wien, Austria.

The approaches for analysis of N-glycans have radically altered in the last 20 years or so. Due to increased sensitivity, mass spectrometry has become the predominant method in modern glycomics. Here, we summarize recent studies showing that the improved resolution and detection by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has contributed greatly to the discovery of a large range of anionic and zwitterionic N-glycan structures across the different kingdoms of life, whereby MALDI-TOF MS in negative mode is less widely performed than in positive mode. Read More

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High Confidence Shotgun Lipidomics Using Structurally Selective Ion Mobility-Mass Spectrometry.

Methods Mol Biol 2021 ;2306:11-37

Center for Innovative Technology, Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN, USA.

Ion mobility (IM) is a gas phase separation strategy that can either supplement or serve as a high-throughput alternative to liquid chromatography (LC) in shotgun lipidomics. Incorporating the IM dimension in untargeted lipidomics workflows can help resolve isomeric lipids, and the collision cross section (CCS) values obtained from the IM measurements can provide an additional molecular descriptor to increase lipid identification confidence. This chapter provides a broad overview of an untargeted ion mobility-mass spectrometry (IM-MS) workflow using a commercial drift tube ion mobility-quadrupole-time-of-flight mass spectrometer (IM-QTOF) for high confidence lipidomics. Read More

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January 2021

Micro-droplet-based calibration for quantitative elemental bioimaging by LA-ICPMS.

Anal Bioanal Chem 2021 May 5. Epub 2021 May 5.

Institute of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 38, 1090, Vienna, Austria.

In this work, a novel standardization strategy for quantitative elemental bioimaging is evaluated. More specifically, multi-element quantification by laser ablation-inductively coupled plasma-time-of-flight mass spectrometry (LA-ICP-TOFMS) is performed by multi-point calibration using gelatin-based micro-droplet standards and validated using in-house produced reference materials. Fully automated deposition of micro-droplets by micro-spotting ensured precise standard volumes of 400 ± 5 pL resulting in droplet sizes of around 200 μm in diameter. Read More

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Noninvasive monitoring of evolving urinary metabolic patterns in neonatal encephalopathy.

Pediatr Res 2021 May 5. Epub 2021 May 5.

Neonatal Research Group, Health Research Institute La Fe, Valencia, Spain.

Background: Infants with moderate and severe neonatal encephalopathy (NE) frequently suffer from long-term adverse outcomes. We hypothesize that the urinary metabolome of newborns with NE reflects the evolution of injury patterns observed with magnetic resonance imaging (MRI).

Methods: Eligible patients were newborn infants with perinatal asphyxia evolving to NE and qualifying for therapeutic hypothermia (TH) included in the HYPOTOP trial. Read More

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Fecal metabolite analysis of Japanese macaques in Yakushima by LC-MS/MS and LC-QTOF-MS.

J Vet Med Sci 2021 May 3. Epub 2021 May 3.

Chubu University Academy of Emerging Sciences.

We performed a comprehensive fecal metabolite analysis using LC-MS/MS and LC-QTOF-MS approaches as a preliminary study. Feces of Japanese macaques on Yakushima Island were collected from five monkeys at two separate locations. Using the former methodology, 59 substances such as free amino acids, nucleotides, nucleosides and nucleic acid bases, and organic acids in the citrate cycle were quantitatively detected and successfully differentiated in two different monkey groups by the concentrations of nucleic acid metabolites and free amino acids. Read More

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First pediatric case of osteomyelitis caused by Robinsoniella peoriensis.

Acta Microbiol Immunol Hung 2021 May 3. Epub 2021 May 3.

1 Department of Medical Microbiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.

Robinsoniella peoriensis is a gram-positive, spore-forming, anaerobic rod. In our study, we isolated R. peoriensis from an open fracture of the left distal tibia of a three-year-old male patient. Read More

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Quantitative Approach Using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-ToF) Mass Spectrometry.

Methods Mol Biol 2021 ;2228:159-166

Future Industries Institute, University of South Australia, Adelaide, Australia.

Quantitation using mass spectrometry (MS) is a routine approach for multiple analytes, including small molecules and peptides. Electrospray-based MS platforms are typically employed, as they provide highly reproducible outputs for batch processing of multiple samples. Quantitation using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (ToF) mass spectrometry, while less commonly adopted, offers the ability to monitor analytes at significantly higher throughput and lower cost compared with ESI MS. Read More

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January 2021

AES and ToF-SIMS combination for single cell chemical imaging of gold nanoparticle-labeled .

Chem Commun (Camb) 2021 May 5. Epub 2021 May 5.

Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, Institut des Sciences Analytiques et Physico-Chimie Pour l'Environnement et les matériaux (IPREM), 2 avenue du Président Angot, 64000 Pau, France.

A chemical fingerprint of the Escherichia coli cell surface labeled by gelatin coated gold nanoparticles was obtained by combining Auger Electron Spectroscopy (AES) for single cell level chemical images, and Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) Tandem MS for unambiguous molecular identification of co-localized species. Read More

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Ionisation of PF: absolute partial electron ionisation cross sections and the formation and reactivity of dication states.

Phys Chem Chem Phys 2021 May 5. Epub 2021 May 5.

Department of Chemistry, University College London, London WC1H 0AJ, UK.

Absolute partial electron ionisation cross sections, and precursor-specific partial electron ionisation cross sections, for the formation of cations from phosphorus trifluoride (PF3) are reported over the electron energy range 50-200 eV. The absolute values are determined by the measurement of cross sections relative to the formation of PF3+ using 2D ion-ion coincidence time-of-flight mass spectrometry and subsequent scaling using binary encounter-Bethe calculations of the total ionisation cross section. This new dataset significantly augments the partial ionisation cross sections for electron ionization of PF3 found in literature, addressing previous discrepancies in the branching ratios of product ions, and provides the first values for the precursor-specific cross sections. Read More

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Thiol functionalized covalent organic framework for highly selective enrichment and detection of mercury by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Analyst 2021 May;146(9):2991-2997

Partner State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 224 Waterloo Road, Kowloon Tong, Hong Kong, SAR, P. R. China.

A spherical thiol-functionalized covalent organic framework (COF-SH) was designed via a facile thiol-yne click reaction of a alkynyl-terminated COF and pentaerythritol tetra(3-mercaptopropionate). The COF-SH was explored as a new adsorbent for the selective enrichment of Hg2+. The as-prepared COF-SH exhibited a uniform mesoporous structure, a high abundance of binding sites, and good chemical stability, which endow it with great performance for the adsorption of Hg2+ and its corresponding maximum adsorption capacity was up to 617. Read More

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Hyper-fast gas chromatography and single-photon ionisation time-of-flight mass spectrometry with integrated electrical modulator-based sampling for headspace and online VOC analyses.

Analyst 2021 May 4. Epub 2021 May 4.

Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, 18059 Rostock, Germany. and Joint Mass Spectrometry Centre, Cooperation Group "Comprehensive Molecular Analytics" (CMA), Helmholtz Zentrum München, 81379 München, Germany.

We developed a novel fast gas chromatography (fastGC) instrument with integrated sampling of volatile organic compounds (VOCs) and detection by single-photon ionisation (SPI) time-of-flight mass spectrometry (TOFMS). A consumable-free electrical modulator rapidly cools down to -55 °C to trap VOCs and inject them on a short chromatographic column by prompt heating to 300 °C, followed by carrier gas exchange from air to helium. Due to the low thermal mass and optical heating, the fastGC is operated within total runtimes including cooling for 30 s and 15 s, referring to hyper-fast GC, and at a constantly increasing temperature ramp from 30 °C to 280 °C. Read More

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Integrating chemical profiling and network pharmacology analysis based on anti-inflammatory effects for quality control of Scutellaria barbata.

Phytochem Anal 2021 May 4. Epub 2021 May 4.

State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China.

Introduction: With the wide application of Scutellaria barbata D. Don for hepatitis and mastitis, its quality control issues have also received increasing attention. Based on the multi-component and multi-target characteristics of traditional Chinese medicine, there is an urgent need to establish a quality evaluation system. Read More

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Alteration in the Cerebrospinal Fluid Lipidome in Parkinson's Disease: A Post-Mortem Pilot Study.

Biomedicines 2021 Apr 29;9(5). Epub 2021 Apr 29.

Clinical Neuroproteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Instituto de Investigación Sanitaria de Navarra (IdiSNA), Universidad Pública de Navarra (UPNA), 31008 Pamplona, Spain.

Lipid metabolism is clearly associated to Parkinson's disease (PD). Although lipid homeostasis has been widely studied in multiple animal and cellular models, as well as in blood derived from PD individuals, the cerebrospinal fluid (CSF) lipidomic profile in PD remains largely unexplored. In this study, we characterized the post-mortem CSF lipidomic imbalance between neurologically intact controls ( = 10) and PD subjects ( = 20). Read More

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Wounding-Induced VOC Emissions in Five Tropical Agricultural Species.

Molecules 2021 Apr 29;26(9). Epub 2021 Apr 29.

Chair of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006 Tartu, Estonia.

Leaf mechanical wounding triggers a rapid release-within minutes-of a blend of volatile organic compounds. A wounding-induced VOC blend is mainly composed of oxygenated ubiquitous stress volatiles such as methanol and volatile products of lipoxygenase (LOX) pathway (mainly C5 and C6 alcohols and aldehydes and their derivatives), but also includes multiple minor VOCs that collectively act as infochemicals, inducing defences in non-damaged plant leaves and neighbouring plants and attracting herbivore enemies. At present, the interspecific variability of the rate of induction and magnitude of wounding-induced emissions and the extent to which plant structural traits and physiological activity alter these emissions are poorly known. Read More

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Liquid Chromatographic Quadrupole Time-of-Flight Mass Spectrometric Untargeted Profiling of (Poly)phenolic Compounds in L. and L. Fruits and Their Comparative Evaluation.

Antioxidants (Basel) 2021 Apr 29;10(5). Epub 2021 Apr 29.

Department of Chemistry "Ugo Schiff", University of Florence, 50019 Sesto Fiorentino, Italy.

This study provided a detailed profiling of the antioxidant and bioactive compounds occurring in three varieties of L. fruits ("Fall Gold", "Glen Ample" and "Tulameen") compared to L. black raspberry ("Jewel" cultivar), adopting a comprehensive untargeted metabolomics approach developed with UHPLC analysis coupled with quadrupole/time-of-flight high resolution mass spectrometry, using the SWATH acquisition protocol. Read More

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Characterization of the Plasma Lipidome in Dairy Cattle Transitioning from Gestation to Lactation: Identifying Novel Biomarkers of Metabolic Impairment.

Metabolites 2021 Apr 30;11(5). Epub 2021 Apr 30.

Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.

The discovery of novel biomarkers for peripartal diseases in dairy cows can improve our understanding of normal and dysfunctional metabolism, and lead to nutritional interventions that improve health and milk production. Our objectives were to characterize the plasma lipidome and identify metabolites associated with common markers of metabolic disease in peripartal dairy cattle. Multiparous Holstein cows ( = 27) were enrolled 30 d prior to expected parturition. Read More

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Streptococcus suis serotyping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

PLoS One 2021 4;16(5):e0249682. Epub 2021 May 4.

Department of Veterinary Public Health, Faculty of Veterinary Sciences, Chulalongkorn University, Bangkok, Thailand.

Streptococcus suis, particularly S. suis serotype 2 (SS2), is an important zoonotic pathogen causing meningitis in humans worldwide. Although the proper classification of the causative and pathogenic serotype is salutary for the clinical diagnosis, cross-reactions leading to the indistinguishability of serotypes by the current serotyping methods are significant limitations. Read More

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A qualitative analysis of seven ivermectin formulations in South Africa.

S Afr Med J 2021 02 18;111(4):288-290. Epub 2021 Feb 18.

Soweto Clinical Trials Centre, Johannesburg, South Africa.

Some South African (SA) healthcare practitioners are promoting the prescription and use of products claiming to contain ivermectin for the treatment and/or prevention of COVID-19 in SA. This study qualitatively analysed seven samples of ivermectin formulations (5 tablet and 2 capsule formulations) being sold in SA for human use. The samples were analysed using a high-performance liquid chromatography instrument connected to a Sciex X500R quadrupole time-of-flight high-resolution mass spectrometer. Read More

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February 2021