Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 20 de 3.078
Filtrer
1.
Int J Biol Macromol ; 280(Pt 1): 135604, 2024 Sep 12.
Article de Anglais | MEDLINE | ID: mdl-39276900

RÉSUMÉ

In this study, utilized algae activated with citric acid and lime juice to develop a novel bioadsorbent, The Algae@CS/Alginate beads were formed by encapsulating the activated algae with chitosan and alginate, producing a nanocomposite that is efficient in removing Basic Fuchsin (BF) dye from water. The beads were characterized by means of a diversity of techniques, such as FTIR, XRD, XPS, SEM and determination the surface area via N2 adsorption/desorption isotherm that permitted that the adsorbent has high surface area 124.43 m2/g. The electrical properties of the BF, including its structure and reactivity, were determined by density functional theory (DFT). The MEP data and the molecular orbitals (HOMO and LUMO), as well as the sites of the electrophilic besides nucleophilic attack places, correspond fairly well, according to DFT. The adsorption process was fitted to Langmuir isothermally, and kinetically to pseudo-second-order (PSOE) model. The adsorption mechanism was identified as chemisorption with an adsorption energy of 32.6 kJ/mol. Thermodynamic research shows that the BF adsorption process by Algae@CS/Alginate beads is spontaneous and endothermic because of the positive ΔHo and negative ΔGo. Through numerical optimization of the programmed, the ideal conditions for adsorption were strongminded to be a pH of 8, a dosage of 0.02 g/25 mL for Algae@CS/Alginate beads, and a concentration of 367.27 mg/g of BF. Using the least amount of intended experiments, the adsorption procedure was optimized by the request of Box-Behnken design (BBD) and answer surface methodology (RSM) in Design-Expert software. Adsorbent reusability test results showed that, following eight successive cycles of adsorption and desorption, the adsorbent was stable and that removal efficacy had not decreased. It additionally demonstrated good efficacy, no alteration in chemical conformation, and the same XRD and FTIR data before and after recycle. Analyze the interaction between the Algae@CS/Alginate beads and the BF.

2.
Sci Total Environ ; 954: 176296, 2024 Sep 14.
Article de Anglais | MEDLINE | ID: mdl-39284449

RÉSUMÉ

A novel metal-organic framework (MOF) material, MIL-100(Fe)-DMA, was synthesized using the solvothermal method. The structure of the MOF was characterized using scanning electron microscopy-energy dispersive X-ray spectroscopy, N2 adsorption-desorption isotherms, X-ray diffraction analysis, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Mössbauer spectroscopy. Batch adsorption experiments were performed to investigate the effects of initial Sr2+ and Cs+ concentrations, adsorption time, pH, and coexisting cations on the adsorption performance of the material. The adsorption mechanism was further elucidated using adsorption kinetics and isotherm models. The results indicated that the adsorption of Sr2+ and Cs+ does not significantly affect the MOF material structure. As reaction time and initial ion concentration increased, the adsorption capacity of MIL-100(Fe)-DMA for Sr2+ and Cs+ increased rapidly and then gradually reached equilibrium. Optimal adsorption occurred under alkaline conditions, with maximum adsorption capacity observed at pH = 8. The adsorption process for Sr2+ and Cs+ was well described by the pseudo-second-order kinetic model, the Weber-Morris model, and the Langmuir adsorption isothermal model. The adsorption process was mainly identified as monolayer chemical adsorption, influenced by multiple factors. Characterization combined with density functional theory calculations revealed that the unsaturated carboxylic acid groups on the surface of the MOFs play a crucial role in the interaction with Sr2+ and Cs+.

3.
ACS Appl Mater Interfaces ; 16(38): 51020-51027, 2024 Sep 25.
Article de Anglais | MEDLINE | ID: mdl-39264821

RÉSUMÉ

FA-MA-Cs ternary cation perovskite exhibits excellent optoelectronic properties and high stabilities against humidity and light soaking and thus has aroused extensive attention in polycrystalline thin film solar cells. Compared with polycrystalline counterparts, FA-MA-Cs ternary cation perovskite single-crystal thin films (SCTFs) have lower defects, better carrier transport capacity, and stability because of lacking grain boundary defects. However, the immature growth technology of SCTFs restricts digging out its optoelectronic potential. Here, we proposed an improved space-confined method to grow large area FA0.9 MA0.05Cs0.05PbI2.7Br0.3 SCTFs using a tunable heating area to control the nucleation and growth process. Its area reaches 64 mm2 with a thickness of 26 µm. The SCTF exhibits high crystallinity, low defect density, long carrier lifetime, and high moisture resistance stability. Besides, a photosensitive chip based on a planar metal-semiconductor-metal photodetector demonstrates linear response to the three primary colors, with a photosensitive range that is 1.5 times that of protocol 3 wide color gamut. Under high-frequency light sources, the on/off ratio reaches 3.9 × 103, and the response time can be as low as 400 ns. Such ultrafast response speed and broad photosensitive range are successfully achieved for imaging applications.

4.
ACS Appl Mater Interfaces ; 16(38): 51055-51064, 2024 Sep 25.
Article de Anglais | MEDLINE | ID: mdl-39276066

RÉSUMÉ

Broadband photodetectors covering ultraviolet (UV) to near-infrared (NIR) wavelengths play an essential role in communications, imaging, and biosensing. Developing a single photodetector with a broadband optical response operating at room temperature can significantly reduce the complexity and cost of receiver systems for multispectral applications. In this work, utilizing the porous structure characteristics of Cs2AgBiBr6:Sn thin films, a self-powered detector with broad spectral response (UV-vis-NIR) was achieved by constructing an effective Cs2AgBiBr6:Sn/PDPP3T heterojunction. This photodetector possesses a broad response spectrum from 350 to 950 nm with an average detection rate exceeding 1011 Jones and maintains excellent photoelectric performance over two months. Sn2+ doping effectively reduces the bandgap of Cs2AgBiBr6, enhancing its near-infrared absorption and optimizing energy level alignment with conjugated polymer (diketopyrrolopyrrole-terthiophene, PDPP3T). More importantly, the porous structure derived from Sn doping significantly improves carrier extraction and transport under a near-infrared light response at the heterojunction interface. Utilizing its broad spectral response characteristics in the UV-vis-NIR range, a novel information transfer and encryption system employing full optical modulation has been realized within a single perovskite photodetector. This work provides a new approach to fabricating lead-free double perovskite broadband photodetectors with potential applications in photonic devices.

5.
Neurobiol Dis ; 201: 106675, 2024 Sep 19.
Article de Anglais | MEDLINE | ID: mdl-39306014

RÉSUMÉ

α-synuclein (αSyn) is a presynaptic and nuclear protein that aggregates in important neurodegenerative diseases such as Parkinson's Disease (PD), Parkinson's Disease Dementia (PDD) and Lewy Body Dementia (LBD). Our past work suggests that nuclear αSyn may regulate forms of DNA double-strand break (DSB) repair in HAP1 cells after DNA damage induction with the chemotherapeutic agent bleomycin1. Here, we report that genetic deletion of αSyn specifically impairs the non-homologous end-joining (NHEJ) pathway of DSB repair using an extrachromosomal plasmid-based repair assay in HAP1 cells. Notably, induction of a single DSB at a precise genomic location using a CRISPR/Cas9 lentiviral approach also showed the importance of αSyn in regulating NHEJ in HAP1 cells and primary mouse cortical neuron cultures. This modulation of DSB repair is regulated by the activity of the DNA damage response signaling kinase DNA-PKcs, since the effect of αSyn loss-of-function is reversed by DNA-PKcs inhibition. Together, these findings suggest that αSyn plays an important physiologic role in regulating DSB repair in both a transformed cell line and in primary cortical neurons. Loss of this nuclear function may contribute to the neuronal genomic instability detected in PD, PDD and LBD and points to DNA-PKcs as a potential therapeutic target.

6.
Nano Lett ; 2024 Sep 27.
Article de Anglais | MEDLINE | ID: mdl-39329391

RÉSUMÉ

Exploring efficient and stable halide perovskite-based photocatalysts is a great challenge due to the balance between the photocatalytic performance, toxicity, and intrinsic chemical instability of the materials. Here, the environmentally friendly lead-free perovskite Cs2AgBiBr6 confined in the mesoporous TiO2 crystal matrix has been designed to enhance the charge carrier extraction and utilization for efficient photocatalytic rifampicin degradation. The as-prepared Cs2AgBiBr6/TiO2 catalyst was stable in air for over 500 days. An S-scheme heterojunction was formed between the (004) plane of Cs2AgBiBr6 and the (101) plane of TiO2 through the Bi-O-Br bonds. The built-in electric field at the interface efficiently promoted the photoinduced charge separation and carrier extraction. The Cs2AgBiBr6/TiO2-200 showed a 92.83% degradation efficiency of rifampicin within 80 min under simulated sunlight illumination (AM 1.5G 100 mW cm-2). This work offers an effective way for the construction of halide perovskite-based photocatalysts with high photocatalytic performance, good stability, and low toxicity simultaneously.

7.
Small ; : e2404188, 2024 Sep 20.
Article de Anglais | MEDLINE | ID: mdl-39301924

RÉSUMÉ

Lead-free halide double perovskite (HDP) Cs2AgBiBr6 has set a benchmark for research in HDP photoelectric applications due to its attractive optoelectronic properties. However, its narrow absorption range is a key limitation of this material. Herein, a novel dopant, palladium (Pd), is doped into Cs2AgBiBr6 and significantly extends the absorption to ≈1400 nm. Pd2+ ions are partially doped in the host lattice, most probably replacing Ag atoms and introducing a sub-bandgap state within the host bandgap, as indicated by the combination of spectroscopical measurements and theoretical calculations. Importantly, this sub-bandgap state extends the photoresponse of Cs2AgBiBr6 up to the NIR-II region of 1300 nm, setting a new record for HDPs. This work demonstrates a novel and efficient dopant for HDPs and highlights the effectiveness of employing a sub-bandgap to broaden the absorption of HDPs, shedding new light on tailoring large bandgap HDPs for NIR optoelectronic applications.

8.
Food Chem X ; 24: 101762, 2024 Dec 30.
Article de Anglais | MEDLINE | ID: mdl-39314538

RÉSUMÉ

An active chitosan (CS) film containing a nano-hydroxyapatite-tea polyphenol (HAP-TP) complex was designed and prepared. The effects of HAP-TP loading on the structural and physicochemical properties of the CS-based film were evaluated. The mechanical and thermal properties of the film were significantly improved by the resulting intermolecular interactions and formation of hydrogen bonds between HAP-TP and CS, which reduced the water vapor and oxygen permeabilities of the film by 29.78 and 35.59 %, respectively. The CS-HAP-TP film exhibited excellent slow-release behavior and antioxidant activity, with a cumulative release rate at 700 h 6.79 % lower than that of CS-TP films. The CS-HAP-TP film significantly inhibited the deterioration of semi-dried golden pompano, and thus helped to retain the taste of umami and sweet amino acids in fish samples, while reducing off-flavor generation. The film therefore shows considerable potential as an active packaging material for the preservation of semi-dried fish products.

9.
Talanta ; 281: 126894, 2024 Sep 14.
Article de Anglais | MEDLINE | ID: mdl-39303326

RÉSUMÉ

This work presents a simple and accurate method for the fast sequential determination of Rh, Pd, and Pt in spent automotive catalysts and e-wastes using high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Extensive research was carried out in model systems on the impact of potential interfering substances on analyte's signals measured in two types of flame (air-C2H2 and N2O-C2H2). Mutual analyte interactions were also taken into account. Different background corrections offered by the HR-CS AAS spectrometer were tested to obtain interference-free analyte signals and the best detectability. Using an air-C2H2 flame and 1 % La solution as a spectrochemical buffer provided good sensitivity and accurate determinations of Rh, Pd, and Pt using a simple calibration graph. Microwave-assisted leaching of PGE from waste samples with aqua regia at 240 °C for 60 min efficiently leached all target metals, which significantly simplified and shortened the sample preparation step. The detectability of the method (detection limit of 0.4, 0.6, and 5 mg kg-1 for Rh, Pd, and Pt, respectively) and precision (< 7 %) were satisfactory. The accuracy of the method was confirmed by analysis of certified reference materials (spent automotive catalyst (ERM-EB504), electronic scrap (BAM-M505a)), and calculated zeta score values. The recoveries for Rh, Pd, and Pt in ERM-EB504 were 93, 101, and 96 %, respectively, and for Pd in BAM-M505a, 97 %. The developed method can be used to assess the value of secondary raw materials, such as various types of spent catalysts and e-waste containing Rh, Pd, and Pt.

10.
Macromol Rapid Commun ; : e2400491, 2024 Sep 05.
Article de Anglais | MEDLINE | ID: mdl-39234916

RÉSUMÉ

Electrochemistry has been widely used in energy storage, metallurgy, chemical synthesis and other fields since its birth using electricity as one of the cheapest reagents. However, compared with the revival of electrochemical synthesis of small molecules, the electrochemical polymerization for preparing macromolecules is still rudimentary due to formidable challenges. Herein, A unique electrochemical polymerization is disclosed between CS2 and diamines at room temperature in an electrolyte-free manner to access poly thioureas. Polythioureas have high selectivity for four metal ions, including Au3+, Ag+, Pt4+, and Hg2+, and can be used as an efficient adsorbent for recovering gold from metal waste.

11.
BMC Microbiol ; 24(1): 328, 2024 Sep 07.
Article de Anglais | MEDLINE | ID: mdl-39244527

RÉSUMÉ

BACKGROUND: Staphylococcus aureus is an infectious bacterium that is frequently found in healthcare settings and the community. This study aimed to prepare rutin-loaded chitosan nanoparticles (Rut-CS NPs) and assess their antibacterial activity against pathogenic strains of S. aureus. RESULTS: The synthesized Rut-CS NPs exhibited an amorphous morphology with a size ranging from 160 to 240 nm and a zeta potential of 37.3 mV. Rut-CS NPs demonstrated significant antibacterial activity against S. aureus strains. Following exposure to Rut-CS NPs, the production of staphyloxanthin pigment decreased by 43.31-89.63%, leading to increased susceptibility of S. aureus to hydrogen peroxide. Additionally, visual inspection of cell morphology indicated changes in membrane integrity and permeability upon Rut-CS NPs exposure, leading to a substantial increase (107.07-191.08%) in cytoplasmic DNA leakage in the strains. Furthermore, ½ MIC of Rut-CS NPs effectively inhibited the biofilm formation (22.5-37.5%) and hemolytic activity (69-82.59%) in the S. aureus strains. CONCLUSIONS: Our study showcases that Rut-CS NPs can serve as a novel treatment agent to combat S. aureus infections by altering cell morphology and inhibiting virulence factors of S. aureus.


Sujet(s)
Antibactériens , Biofilms , Chitosane , Tests de sensibilité microbienne , Nanoparticules , Rutoside , Staphylococcus aureus , Xanthophylles , Staphylococcus aureus/effets des médicaments et des substances chimiques , Chitosane/pharmacologie , Chitosane/composition chimique , Rutoside/pharmacologie , Rutoside/composition chimique , Nanoparticules/composition chimique , Antibactériens/pharmacologie , Antibactériens/composition chimique , Biofilms/effets des médicaments et des substances chimiques , Xanthophylles/pharmacologie , Xanthophylles/composition chimique , Hémolyse/effets des médicaments et des substances chimiques , Facteurs de virulence , Infections à staphylocoques/microbiologie , Infections à staphylocoques/traitement médicamenteux , Humains , Peroxyde d'hydrogène/pharmacologie
12.
Small Methods ; : e2400310, 2024 Sep 03.
Article de Anglais | MEDLINE | ID: mdl-39225357

RÉSUMÉ

Lead-based halide perovskites have gained significant prominence in recent years in optoelectronics and photovoltaics, owing to their exceptional optoelectronic properties. Nonetheless, the toxicity of lead (Pb) and the stability concern pose obstacles to their potential for future large-scale market development. Herein, stable lead-free Cs3Bi2I9 (CBI) films are presented with smooth and compact morphologies synthesized via chemical vapor deposition (CVD), demonstrating their application as an UV photodetector in a self-powered way. The self-powered photodetectors (SPDs) exhibit remarkable characteristics, including a responsivity of 1.57 A W-1 and an impressive specific detectivity of 3.38 × 1013 Jones under the illumination of 365 nm at zero bias. Furthermore, the SPDs exhibit a nominal decline (≈2.2%) in the photocurrent under constant illumination over 500 h, highlighting its impressive long-term operational stability. Finally, the real-time UV-detection capability of the device is demonstrated by measuring the photocurrent under various conditions, including room light and sunlight at different times. These findings offer a new platform for synthesizing stable and high-quality perovskite films, and SPDs for advancing the development of wearable and portable electronics.

13.
Cureus ; 16(8): e66661, 2024 Aug.
Article de Anglais | MEDLINE | ID: mdl-39262523

RÉSUMÉ

The introduction of the Femoral Neck System (FNS) represents a promising alternative to traditional cancellous cannulated (CC) screw fixation for managing intra-capsular neck of femur (ICNF) fractures. This case report aims to validate its safety and report the outcomes in a young patient. The findings demonstrate that the FNS possesses excellent biomechanical properties and provides significantly greater overall construct stability bearing in mind, that it was used in a Pauwels Classification Grade 3 ICNF fracture.

14.
J Thorac Dis ; 16(8): 4994-5004, 2024 Aug 31.
Article de Anglais | MEDLINE | ID: mdl-39268126

RÉSUMÉ

Background: The outbreak of the novel coronavirus 19 has led to unprecedented clinical challenges globally. Various therapeutic and pharmacologic interventions have been proposed, yet evidence of their long-term efficacy remains limited. Corticosteroids (CS) have shown efficacy in the sub-acute phase of the pandemic. This study aims to evaluate the long-term effects on pulmonary function tests (PFTs) in patients treated with CS during acute coronavirus disease 2019 (COVID-19) infection. Methods: A retrospective study was conducted from February 2020 to March 2021. Clinical and demographic data were extracted from electronic medical records of patients attending the post-COVID outpatient clinic at the Pulmonary Institute of Soroka University Medical Center. A multivariate linear mixed effects model was employed to obtain adjusted estimates for the impact over time. Results: The study included 405 patients, of whom 155 (38.3%) received CS treatment. Approximately 60% completed two or more follow-up visits. PFTs [forced expiratory volume in the first second (FEV1), forced vital capacity (FVC)] returned to baseline more rapidly (0.9% and 0.85% per month, respectively) in patients treated with CS. This accelerated recovery was observed across all patients, including those with a body mass index (BMI) above 30 kg/m2 and those with known chronic lung disease. Conclusions: Systemic CS treatment during acute COVID-19 infection was associated with a faster recovery of PFTs during long-term follow-up, even among subgroups at higher risk of long-term pulmonary damage.

15.
Article de Anglais | MEDLINE | ID: mdl-39269401

RÉSUMÉ

BACKGROUND: Reconnection of the mitral isthmus (MI) is common after radiofrequency ablation (RFA). Vein of Marshall ethanol infusion (VOMEI) expedites MI ablation, but long-term results are unclear. OBJECTIVES: This study sought to determine anatomic substrates of failed MI ablation, with and without VOMEI. METHODS: Consecutive VOMEI procedures were included (n = 231; of which 140 were de novo ablations and 91 were prior RFA failures (rescue VOMEI). MI conduction mechanisms were studied with vein of Marshall (VOM) electrograms obtained with a 2-F octapolar catheter, mapping, and differential pacing. RESULTS: In rescue VOMEI, intact VOM electrograms showed epicardial connections, epi-endocardial dissociation, and VOM conduction in pseudo-MI block. After VOMEI, after a follow-up of 725 ± 455 days, 78 patients (33.7%) experienced recurrence. Of those, 36 (46%) had evidence of MI reconnection and 42 had other mechanisms. Of the 36 patients with MI reconnection, endocardial radiofrequency (RF) at the annular MI restored block in 16 (45%), and coronary sinus (CS) RF was required in 20 (55%). Post-VOMEI recurrence mechanisms included CS connection-dependent arrhythmias: CS-mediated perimitral flutter, CS-to-left atrium (LA) and CS ostial re-entry, and CS focal activity. Intraprocedural factors associated with MI reconnection included volume of ethanol delivered ≥4 mL (OR: 0.74; P = NS), CS ablation at VOMEI (OR: 4.05; P = 0.003), and age (OR: 1.06; P = 0.011). CONCLUSIONS: MI reconnections after RFA are due to epicardial connections from VOM. Recurrences after VOMEI are due to incomplete annular MI RFA and CS arrhythmogenesis including CS-mediated perimitral flutter, CS-to-LA re-entry and CS focal activity. Adding complete CS disconnection to VOMEI may prevent recurrences.

16.
Article de Anglais | MEDLINE | ID: mdl-39269467

RÉSUMÉ

Impaired alveolar epithelial regeneration in patients with idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) is attributed to telomere dysfunction in type II alveolar epithelial cells (A2Cs). Genetic susceptibility, aging, and toxicant exposures, including tobacco smoke (TS), contribute to telomere dysfunction in A2Cs. Here we investigated whether improvement of telomere function plays a role in CSP7-mediated protection of A2Cs against ongoing senescence and apoptosis during bleomycin (BLM)-induced pulmonary fibrosis (PF) as well as alveolar injury caused by chronic TS exposure. We found a significant telomere shortening in A2Cs isolated from IPF and COPD lungs in line with other studies. These cells showed increased p53 in addition to its post-translational modification with induction of activated caspase-3 and ß-galactosidase, suggesting a p53-mediated loss of A2C renewal. Further, we found increased expression of SIAH-1, a p53-inducible E3 ubiquitin ligase known to down-regulate telomere repeats binding factor 2 (TRF2). Consistent with the loss of TRF2 and upregulation of TRF1, telomerase reverse transcriptase (TERT) was downregulated in A2Cs. A2Cs from fibrotic lungs of mice either repeatedly instilled with BLM or isolated from chronic TS exposure-induced lung injury model showed reduced telomere length along with induction of p53, PAI-1, SIAH1 and TRF1 as well as loss of TRF2 and TERT, which were reversed in wild-type mice after treatment with CSP7. Interestingly, PAI-1-/- mice, or those lacking microRNA-34a expression in A2Cs, resisted telomere dysfunction, while uPA-/- mice failed to respond to CSP7 treatment, suggesting p53-microRNA-34a feed-forward induction and p53-uPA pathway contributes to telomere dysfunction.

17.
Int J Cosmet Sci ; 2024 Sep 16.
Article de Anglais | MEDLINE | ID: mdl-39282751

RÉSUMÉ

OBJECTIVE: Excessive and unpleasant odours that emanate from the skin can induce bromhidrosis and substantially impair a person's quality of life. Enzymatic pathways generating unpleasant odours are well detailed, and among them, the C-S lyase is one of the enzymes involved in the conversion of non-volatile precursors into thiol-type malodorous volatile molecules such as 3M3SH. This study aimed to investigate the variation of axillary odour intensity correlated with Staphylococcus (S.) hominis C-S lyase activity within a group of volunteers after a physical activity. METHODS: First, a group of 24 volunteers from the same ethnicity with standardized hygienic and alimentary practices participated in a supervised indoor cycling activity. Following this session, worn T-shirts were recovered to enable the olfactory evaluation of axillary odours by qualified experts. To go further, the microbiota from the axillary zone of each volunteer was sampled and the bacterial relative abundance was investigated by using 16S rRNA metasequencing. Then, S. hominis isolates were obtained by culturomics from these microbiota samples and the C-S lyase activity was measured by spectrofluorometry in protein crude extracts. RESULTS: The evaluation of the odour intensity revealed that within the panel, two groups were significantly distinct. A non-odorous group and a malodorous one with volunteers having unpleasant odours. The 16S rRNA metasequencing reveals differences in bacterial communities between the two groups with a significant increase in the relative abundance of S. hominis in the malodorous group compared with the non-odorous one. The C-S lyase activities measured on S. hominis sampled on volunteers from the two groups demonstrate that for an equivalent quantity of protein, this enzymatic activity is significantly higher for the samples originating from the malodorous group. CONCLUSION: Hence, this study demonstrates that beyond the increase of S. hominis relative abundance, the C-S lyase enzymatic activity of this bacteria is also higher in volunteers with unpleasant axillary odours.


OBJECTIF: Les odeurs excessives et désagréables qui émanent de la peau peuvent induire une bromhidrose et altérer considérablement la qualité de vie d'une personne. Les voies enzymatiques générant des odeurs désagréables sont bien détaillées, et parmi elles, la C­S lyase est l'une des enzymes impliquées dans la conversion de précurseurs non volatils en molécules volatiles malodorantes de type thiols, telles que le 3M3SH. Cette étude avait pour objectif d'investiguer la variation de l'intensité de l'odeur axillaire corrélée à l'activité de la C­S lyase de Staphylococcus (S.) hominis d'un groupe de volontaires après la pratique d'une activité sportive. MÉTHODES: Un groupe de 24 volontaires de la même ethnie ayant des pratiques hygiéniques et alimentaires standardisées ont participé à une séance calibrée de vélo d'intérieur. Après cette activité, les t­shirts portés ont été récupérés pour permettre l'évaluation olfactive des odeurs axillaires par des experts qualifiés. Pour aller plus loin, le microbiote de la zone axillaire de chaque volontaire a été prélevé et l'abondance relative des bactéries a été étudiée par métaséquençage de l'ARNr 16S. Ensuite, des isolats de S. hominis ont été obtenus par culturomique à partir de ces échantillons de microbiote et l'activité de la C­S lyase a été mesurée par spectrofluorométrie dans des extraits protéiques totaux. RÉSULTATS: L'évaluation de l'intensité des odeurs a révélé qu'au sein du panel, deux groupes se distinguaient de manière significative. Un groupe non­odorant et un groupe malodorant avec des volontaires ayant des odeurs axillaires désagréables. Le métaséquençage de l'ARNr 16S révèle des différences dans les communautés bactériennes entre les deux groupes avec une augmentation significative de l'abondance relative de S. hominis dans le groupe malodorant par rapport au groupe non­odorant. L'activité enzymatique de la C­S lyase mesurée à partir d'isolats de S. hominis prélevés sur des volontaires des deux groupes démontrent que, pour une quantité équivalente de protéines, cette activité enzymatique est significativement plus élevée pour les échantillons provenant du groupe malodorant. CONCLUSION: Cette étude démontre qu'au­delà de l'augmentation de l'abondance relative de S. hominis, l'activité de la C­S lyase de cette bactérie est également plus élevée chez les volontaires présentant des odeurs axillaires désagréables.

18.
Talanta ; 281: 126811, 2024 Sep 04.
Article de Anglais | MEDLINE | ID: mdl-39241647

RÉSUMÉ

The analysis of per- and polyfluoroalkyl substances (PFAS) via sum parameters like extractable organic fluorine (EOF) in combination with high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) is highly promising regarding fluorine sensitivity and selectivity. However, the HR-CS-GFMAS method includes several drying and heating steps which can lead to losses of volatile PFAS before the molecular formation step using e.g., GaF formation. Hence, the method leads to a strong discrimination of PFAS within the EOF depending on their physical/chemical properties and is therefore associated with reduced accuracy. To reduce this discrepancy and to indicate realistic PFAS pollution values, an optimization of the HR-CS-GFMAS method for PFAS analysis is needed. Hence, we determined fluorine response factors of several PFAS with different physical/chemical properties upon application of systematic optimization steps. We could therefore improve the method's sensitivity for PFAS analysis using a modifier drying pre-treatment step followed by a sequential injection of sample solutions. The highest improvement in sensitivity of volatile PFAS was shown upon addition of a Mg modifier during drying pre-treatment. Thereby, during optimization the relative standard deviation of fluorine response factors could be reduced from 55 % (initial method) to 27 % (optimized method) leading to a more accurate determination of organofluorine sum parameters. The method provides an instrumental LOD and LOQ of ß(F) 1.71 µg/L and 5.13 µg/L, respectively. Further validation aimed to investigate several matrix effects with respect to water matrices. Here, substance-specific behavior was observed. For example, perfluorooctanoic acid (PFOA) which was used as calibrator, showed signal suppressions upon high chloride concentrations (>50 mg/L). Hence, a thorough separation of Cl from analytes during sample preparation is needed for accurate sum parameter analysis.

19.
Nanotechnology ; 35(47)2024 Sep 06.
Article de Anglais | MEDLINE | ID: mdl-39240071

RÉSUMÉ

Inflammation involving adipose macrophages is an important inducer of obesity. Regulating macrophages polarization and improving the inflammatory microenvironment of adipose tissue is a new strategy for the treatment of obesity. An amphiphilic chondroitin sulfate phenylborate derivative (CS-PBE) was obtained by modifying the main chain of chondroitin sulfate with the hydrophobic small molecule phenylborate. Using CS-PBE self-assembly, macrophage targeting, reactive oxygen species (ROS) release and celastrol (CLT) encapsulation were achieved. The cytotoxicity, cellular uptake, internalization pathways and transmembrane transport efficiency of CS-PBE micelles were studied in Caco-2 and RAW264.7 cells. Hemolysis and organotoxicity tests were performed to assess the safety of the platform, while its therapeutic efficacy was investigated in high-fat diet-induced obese mice. Multifunctional micelles with macrophage targeting and ROS clearance capabilities were developed to improve the efficacy of CLT in treating obesity.In vitrostudies indicated that CS-PBE micelles had better ability to target M1 macrophages, better protective effects on mitochondrial function, better ability to reduce the number of LPS-stimulated M1 macrophages, better ability to reduce the number of M2 macrophages, and better ability to scavenge ROS in inflammatory macrophages.In vivostudies have shown that CS-PBE micelles improve inflammation and significantly reduce toxicity of CLT in the treatment of obesity. In summary, CS-PBE micelles could significantly improve the ability to target inflammatory macrophages and scavenge ROS in adipose tissue to alleviate inflammation, suggesting that CS-PBE micelles are a highly promising approach for the treatment of obesity.


Sujet(s)
Macrophages , Micelles , Mitochondries , Obésité , Espèces réactives de l'oxygène , Animaux , Espèces réactives de l'oxygène/métabolisme , Souris , Obésité/traitement médicamenteux , Obésité/métabolisme , Mitochondries/effets des médicaments et des substances chimiques , Mitochondries/métabolisme , Humains , Macrophages/effets des médicaments et des substances chimiques , Macrophages/métabolisme , Cellules RAW 264.7 , Chondroïtines sulfate/composition chimique , Chondroïtines sulfate/pharmacologie , Cellules Caco-2 , Triterpènes pentacycliques/pharmacologie , Triterpènes pentacycliques/composition chimique , Souris de lignée C57BL , Mâle , Alimentation riche en graisse/effets indésirables , Triterpènes/pharmacologie , Triterpènes/composition chimique
SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE