Publications by authors named "Chaker J"

This study presents an optimized microwave-assisted method for the green synthesis of silver nanoparticles (AgNPs) using a root extract obtained from DC. The influence of temperature, reagent concentration, and irradiation time was systematically investigated to enhance synthesis yield. Characterization techniques including XRD, UV-vis, FTIR, XPS, and zetametry were employed to confirm the successful formation of nanoparticles with a metallic silver core (∼17 nm) functionalized with organic molecules derived from the plant extract.

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Over the past few decades, numerous environmental chemicals from solvents to pesticides have been suggested to be involved in the development and progression of neurodegenerative diseases. Most of the evidence has accumulated from occupational or cohort studies in humans or laboratory research in animal models, with a range of chemicals being implicated. What has been missing is a systematic approach analogous to genome-wide association studies, which have identified dozens of genes involved in Alzheimer's disease, Parkinson's disease and other neurodegenerative diseases.

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The chemical burden on the environment and human population is increasing. Consequently, regulatory risk assessment must keep pace to manage, reduce, and prevent adverse impacts on human and environmental health associated with hazardous chemicals. Surveillance of chemicals of known, emerging, or potential future concern, entering the environment-food-human continuum is needed to document the reality of risks posed by chemicals on ecosystem and human health from a one health perspective, feed into early warning systems and support public policies for exposure mitigation provisions and safe and sustainable by design strategies.

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Introduction And Importance: Synovial sarcoma is a malignant soft tissue tumor typically found near joints; its occurrence in the inguinal region is very rare.

Case Presentation: We report a 23-years-old who presented with lower limb swelling. Imaging studies revealed a tumor in the groin area, compressing the femoral vein.

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In an increasingly chemically polluted environment, rapidly characterizing the human chemical exposome (i.e., chemical mixtures accumulating in humans) at the population scale is critical to understand its impact on health.

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Paracetamol/acetaminophen (N-acetyl-p-aminophenol, APAP) is a top selling analgesic used in more than 600 prescription and non-prescription pharmaceuticals. To study efficiently some of the potential undesirable effects associated with increasing APAP consumption (e.g.

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Article Synopsis
  • A collaborative study involving 16 participants from nine European countries aimed to standardize the detection of environmental contaminants in fish samples using advanced analytical techniques like liquid chromatography and gas chromatography paired with high-resolution mass spectrometry.
  • Participants analyzed freeze-dried fish samples from contaminated and reference sites, identifying a varying percentage of spiked compounds, and yielding unique features depending on the analytical method used.
  • Results showed that inconsistencies in the identification of contaminants were largely influenced by differing data analysis methods among participants, highlighting the need for improved standardization in environmental screening practices.
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Study Question: Do paracetamol (N-acetyl-para-aminophenol (APAP) or acetaminophen) and/or its metabolites affect human sperm Ca2+-signalling and function?

Summary Answer: While APAP itself does not interact with Ca2+-signalling in human sperm, its metabolite N-arachidonoyl phenolamine (AM404), produced via fatty acid amide hydrolase (FAAH), interferes with human sperm Ca2+-signalling and function through a suggested CatSper channel-dependent action.

What Is Known Already: Studies have shown that adult men with high urinary levels of over-the-counter mild analgesic APAP have impaired sperm motility and increased time-to-pregnancy.

Study Design, Size, Duration: This study consists of (i) an in vivo human pharmaceutical APAP exposure experiment to understand to what degree APAP reaches the sperm cells in the seminal fluid; (ii) in vitro calcium imaging and functional experiments in freshly donated human sperm cells to investigate CatSper channel-dependent activation by APAP and its metabolites; and (iii) experiments to understand the in situ capabilities of human sperm cells to form APAP metabolite AM404.

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Sample preparation of biological samples can have a substantial impact on the coverage of small molecules detectable using liquid chromatography-high-resolution mass spectrometry (LC-HRMS). This initial step is particularly critical for the detection of externally derived chemicals and their metabolites (internal chemical exposome) generally present at trace levels. Hence, our objective was to investigate how blood sample preparation methods affect the detection of low-abundant chemicals and to propose alternative methods to improve the coverage of the internal chemical exposome.

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The technological advances in high-resolution mass spectrometry (HRMS), associated with the development of bioinformatics tools, allows the simultaneous detection of tens of thousands of chemical signals in biological matrices, including exogenous (i.e. xenobiotics) and endogenous molecules.

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Background: Knowledge of exact signalling events during migraine attacks is lacking. Various substances are known to trigger migraine attacks in patients and calcitonin gene-related peptide antagonising drugs are effective against migraine pain. Here, we investigated the signalling pathways involved in three different mouse models of provoked migraine and relate them to calcitonin gene-related peptide and other migraine-relevant targets.

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The holistic characterisation of the human internal chemical exposome using high-resolution mass spectrometry (HRMS) would be a step forward to investigate the environmental ætiology of chronic diseases with an unprecedented precision. HRMS-based methods are currently operational to reproducibly profile thousands of endogenous metabolites as well as externally-derived chemicals and their biotransformation products in a large number of biological samples from human cohorts. These approaches provide a solid ground for the discovery of unrecognised biomarkers of exposure and metabolic effects associated with many chronic diseases.

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It is well known that the splitting of tablets can bring serious risks to the health of the treated animals, e.g., the possible adverse reactions caused by overdoses of fenbendazole or aspirin.

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The recent advances of novel methodologies such as non-targeted and suspect screening based on high-resolution mass spectrometry (HRMS) have paved the way to a new paradigm for exposure assessment. These methodologies allow to profile simultaneously thousands of small unknown molecules present in environmental and biological samples, and therefore hold great promises in order to identify more efficiently hazardous contaminants potentially associated with increased risks of developing adverse health outcomes. In order to further explore the potential of these methodologies and push the transition from research applications towards regulatory purposes, robust harmonized quality standards have to be implemented.

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The analgesic paracetamol/acetaminophen (N-acetyl-4-aminophenol, APAP) is commonly used to relieve pain, fever and malaise. While sales have increased worldwide, a growing body of experimental and epidemiological evidence has suggested APAP as a possible risk factor for various health disorders in humans. To perform internal exposure-based risk assessment, the use of accurate and optimized biomonitoring methods is critical.

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The influence of hydrogels on the nanostructural formation of siloxane-polyether nanocomposites was examined. The nanostructure was studied with small-angle X-ray scattering (SAXS) to determine the siloxane nanostructure aggregation mechanisms. The interactions between matrix and drug were examined by infrared spectroscopy to verify the compatibility of the drug with the matrix.

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The technological advances of cutting-edge high-resolution mass spectrometry (HRMS) have set the stage for a new paradigm for exposure assessment. However, some adjustments of the metabolomics workflow are needed before HRMS-based methods can detect the low-abundant exogenous chemicals in human matrixes. It is also essential to provide tools to speed up marker identifications.

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Intragenic antimicrobial peptides (IAPs) are internal sequences of proteins with physicochemical similarities to Antimicrobial Peptides (AMPs) that, once identified and synthesized as individual entities, present antimicrobial activity. Many mature proteins encoded by the genomes of virtually any organism may be regarded as inner reservoirs of IAPs, conferring them ample biotechnological potential. However, IAPs may also share shortcomings with AMPs, such as low half-life in biological media and non-specific adsorption in eukaryotic cells.

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An aggregation-induced emission enhancement (AIEE) effect in fluorescent lipophilic 2,1,3-benzothiadiazole (BTD) derivatives and their organic nanoaggregates were studied. A set of techniques such as single-crystal X-ray, dynamic light scattering (DLS), electron paramagnetic resonance (EPR), UV-vis, fluorescence, and density functional theory (DFT) calculations have been used to decipher the formation/break (kinetics), properties, and dynamics of the organic nanoaggregates of three BTD small organic molecules. An in-depth study of the excited-state also revealed the preferential relaxation emissive pathways for the BTD derivatives and the dynamics associated with it.

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Here, we assessed the feasibility of hot-melt extrusion (HME) to obtain effervescent drug products for the first time. For this, a combined mixture design was employed using paracetamol as a model drug. Extrudates were obtained under reduced torque (up to 0.

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The present study aimed to analyze how the printing process affects the final state of a printed pharmaceutical product and to establish prediction models for post-printing characteristics according to basic printing settings. To do this, a database was constructed through analysis of products elaborated with a distinct printing framework. The polymers acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and high-impact polystyrene (HIPS) were tested in a statistically-based experiment to define the most critical printing factors for mass, mass variation, printing time, and porosity.

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We describe here a green method for the preparation of silver nanoparticles (AgNPs), by a microwave-assisted synthesis route using underbark extract, with antibacterial activity. After optimizing the synthesis parameters with a Box-Benhken designed experiment, samples were characterized by powder XRD, TEM, UV-Vis spectroscopy, FTIR and zetametry. Using the overall optimized conditions of synthesis - time of reaction 15 min at 200 °C and plant extract/AgNO volume ratio equal to 10% - highly crystalline ∼13.

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ADAM10 is a transmembrane metalloprotease that is essential for development and tissue homeostasis. It cleaves the ectodomain of many proteins, including amyloid precursor protein, and plays an essential role in Notch signaling. ADAM10 associates with six members of the tetraspanin superfamily referred to as TspanC8 (Tspan5, Tspan10, Tspan14, Tspan15, Tspan17, and Tspan33), which regulate its exit from the endoplasmic reticulum and its substrate selectivity.

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In this work, we describe the preparation and characterization of highly magnetizable chloromethylated polystyrene-based nanocomposite beads. For synthesis optimization, acid-resistant core-shelled maghemite (γ-FeO) nanoparticles are coated with sodium oleate and directly incorporated into the organic medium during a suspension polymerization process. A crosslinking agent, ethylene glycol dimethacrylate, is used for copolymerization with 4-vinylbenzyl chloride to increase the resistance of the microbeads against leaching.

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The development of supported catalysts based on simple procedures without waste products and time-consuming steps is highly desirable. In this paper, self-supported nickel-based nanoparticles were obtained at the surface of the germanophosphate glasses by bottom-up process and evaluated as potential catalysts for the benzyl alcohol oxidation and bis(indolyl)methanes synthesis. A classical melt-quenching technique was used for preparing the nickel-doped germanophosphate glasses, followed by annealing under a hydrogen atmosphere at 400 °C for two different times.

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