Rodgerslacroix4919

The most commonly used technique for monitoring microbial contamination in cosmetic products is plate counting. In this contribution, headspace - gas chromatography (HS-GC) coupled to mass spectrometry (MS) or ion mobility spectrometry (IMS) is proposed as a technique to evaluate rapidly and accurately the state of microbial colonies in cosmetic creams using the volatile organic compounds produced by microorganisms (MVOC). The work focuses on monitoring two of the microorganisms that most frequently occur in such creams, Candida albicans and Staphylococcus aureus. In addition, two different types of ingredient with antimicrobial properties (a chemical preservative and a natural preservative) were added to study the behaviour of these microorganisms under different conditions. The facial creams were elaborated and inoculated with the two above microorganisms, and then sampled weekly for 4 weeks, analysing the evolution of the MVOCs by HS-GC-MS and HS-GC-IMS. In addition, microbial contamination was determined by the classical plate counting method. The pH, colour, viscosity and water activity parameters were also measured. The use of chemometric tools is essential because of the large amount of data generated, and different models based on discriminant analysis with an orthogonal projection on latent structures (OPLS-DA) were constructed. The optimal models obtained by both analytical techniques allowed differentiation between contaminated and non-contaminated creams, with a validation success rate of 94.4%. In addition, MVOC monitoring also allowed assessment of the microbial concentration.This work reports on the development of the first capillary electrophoresis methodology for the elucidation of extracellular vesicles' (EVs) electrokinetic distributions. The approach is based on capillary electrophoresis coupled with laser-induced fluorescent (LIF) detection for the identification and quantification of EVs after their isolation. Sensitive detection of these nanometric entities was possible thanks to an 'inorganic-species-free' background electrolyte. This electrolyte was made up of weakly charged molecules at very high concentrations to stabilize EVs, and an intra-membrane labelling approach was used to prevent EV morphology modification. The limit of detection for EVs achieved using the developed CE-LIF method reached 8 × 109 EV/mL, whereas the calibration curve was acquired from 1.22 × 1010 to 1.20 × 1011 EV/mL. The CE-LIF approach was applied to provide the electrokinetic distributions of various EVs of animal and human origins, and visualize different EV subpopulations from our recently developed high-yield EV isolation method.Herein, some (modified) paper-based substrates were prepared and utilized as extractive phases in a microfluidic device and their extraction performances examined for analytes with different polarities. MAPK inhibitor Reagents including hexadecyltrimethoxysilane (HDTMS), phenyltrimethoxysilane (PTES), (3-aminopropyl) triethoxysilane (APTES) and 3-(2,3-epoxypropoxy) propyltrimethoxysilane (EPPTMOS) were implemented for the modification process. Due to the induction of different silane functional groups, it was anticipated to have various interactions for the tested analytes. Eventually, the prepared paper sheets were used as extractive phases for solid-phase extraction within a microfluidic system. The microfluidic setup not only improves the mechanical stability of the paper-based phases but also facilitated the mass transfer process and decreases the energy consumption. The selected analytes contained antidepressant drugs, organophosphates and triazine toxins, having different structures and polarities. Afterward, the existing interactions between the paper-based sorbents and the selected analytes were investigated by Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA) for data analysis. According to the obtained data, the PTES modified surface paper was selected for quantitative investigation and optimization. The major parameters associated with the extraction performance were studied. A linear range was obtained for amitriptyline and trimipramine, 0.05-200 μg L-1, and the calibration graph for clomipramine was linear in the range of 0.02-200 μg L-1. The employment of microfluidic device in conjunction with gas chromatography-mass spectrometry led to the limits of detections of 0.005-0.01 μgL-1 for the antidepressant drugs. The relative recoveries for the tested drugs in urine samples were in the range of 95-103%.Inductively coupled plasma - mass spectrometry (ICP-MS) is an essential tool for quantitative ultratrace elemental and isotopic determinations in the biological and biomedical fields. In addition, sensitive and multiplexed quantification of target biomolecules in biological fluids and single-cells by ICP-MS can be carried out using metal elements or their isotopes as labels of immunoreaction and hybridization specific-recognition reactions. Following similar strategies, the bioimaging of biomolecules in tissues and single-cells by laser ablation (LA)-ICP-MS can be also achieved. Sensitivity can be further increased by resorting to amplification strategies based on the use of labels containing several atoms of a given elemental (or isotopic) reporter, such as inorganic nanoparticles (NPs). In this review, we intend to highlight the progress achieved in this active research area. Following the introduction, a short report of the characteristics of the most relevant NPs used as labels of specific-recognition reactions for ICP-MS detection, as well as the most common labelling routes are given. Then, the applications of NPs-labelled detection probes used in combination with ICP-MS (either with liquid nebulization or LA sampling) for identification and determination of proteins and oligonucleotides in biological samples are thoroughly reviewed. In the conclusions section, the challenges faced and the expected advances in this topic are underlined.Bacterial pneumonia is a lethal condition, and approximately 40% of bacterial pneumonia patients experience parapneumonic effusion (PPE). Based on the severity of inflammation, PPEs can be categorized as early-stage uncomplicated PPE (UPPE), advanced-stage complicated PPE (CPPE) and, most seriously, thoracic empyema. Appropriate antibiotic treatment at the early stage of PPE can prevent PPE progression and reduce mortality, indicating that understanding PPE generation and components can help researchers develop corresponding treatment strategies for PPE. To this end, metabolomes of 73 PPE (38 UPPE and 35 CPPE samples) and 30 malignant pleural effusion (MPE) samples were profiled with differential 12C2-/13C2-isotope dansylation labeling-based mass spectrometry. We found that PPE is characterized by elevated levels of dipeptides, especially for PPEs at advanced stages. Furthermore, with integrated proteomic and transcriptomic analyses of PPEs, the levels of dipeptides were strongly associated with the production of interleukin-8 (IL-8), an inflammation-associated cytokine.