Publications by authors named "B Ahmed"

720 Publications

SPR based gold nano-probe as optical sensor for cysteine detection via plasmonic enhancement in the presence of Cr.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Sep 4;265:120356. Epub 2021 Sep 4.

Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia. Electronic address:

A selective and sensitive detection of L-cysteine (Cys) is an important tool for various biological studies. Here, Au nanoparticles (NPs) were prepared by chemical reduction technique. The probe was developed to detect and quantify Cys in the presence of Cr ions which acts as a cross linker. The citrate capped Au NPs probe was analyzed by UV-visible spectrophotometry, TEM, EDAX, FTIR, DLS, XPS and zetasize. The zeta potential and effective size of Au NPs were -41.22 mV and 12 nm, respectively. The Cys interaction with Au NPs showed drastic colour variation from red to purple and colourless with rapid response time of 1 min. The limit of detection (LOD) of Au NPs probe was as low as 0.012 nM. The TEM image of Au NPs after Cys interaction verified the aggregation that resulted in colour change. The XPS core level scans of Au 4f showed 0.3 eV red shift when Cyswas interacted. The Au NPs sensor is highly selective for Cys with excellent reproducibility. Acidic pH slightly favored Cys detection. Further, the probe was applied to estimate Cys quantity from milk, urine, blood and environmental augmented samples in the presence of other amino acids . The study suggests that the proposed Au NPs could detect Cys with high accuracy from various biological samples.
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http://dx.doi.org/10.1016/j.saa.2021.120356DOI Listing
September 2021

Microplastics and trace metals in fish species of the Gulf of Mannar (Indian Ocean) and evaluation of human health.

Environ Pollut 2021 Sep 6;291:118089. Epub 2021 Sep 6.

Department of Earth & Environmental Sciences, Institute of Environmental Geosciences, Pukyong National University, Busan, 608-737, South Korea.

The importance of microplastic (MPs) contamination in marine environments is reflected by increasing number of studies in fish species. Some even dedicated to the toxicological effects from the ingestion. Microplastics (MPs) and their trace metal composition were examined in the muscle and intestine of five commercially important fish species (i.e., Sufflamen fraenatus, Heniochus acuminatus, Atropus atropos, Pseudotriacanthus and Leiognathus brevirostris) from Thoothukudi at the Gulf of Mannar coast in south India. The abundance and morphology of MPs (size, shape, and texture) in muscle and intestinal were investigated by micro-Fourier Transform Infrared Spectroscopy (μ-FT-IR) and atomic force microscope (AFM). ICP-OES was used to investigate the adsorption/leaching of trace metals in microplastics in order to assess health risk for adults and children. Particles of 100-250 μm and white color dominated, and the mean abundances (items/100 g) of total MPs were more in Pseudotriacanthus (muscle: 51.2; intestine: 50.1) compared to Heniochus acuminatus (muscle: 9.6; intestine: 15), Leiognathus brevirostris (muscle: 12; intestine: 13.2) and Atropus atropus (muscle: 15.2; intestine: 44.1). Polyethylene (35.3%), polypropylene (27.2%), polyamide (nylon) (22.2%) and fiber (15.3%) represented the MPs present in muscles, and polyamide (nylon) (30.2%), polyethylene (28.1%), polypropylene (25.9%), and fiber (15.8%) composed the intestine MPs. We estimated possible consumption of 121-456 items of MPs/week by adults and about 19-68 items of MPs/week by children by considering the sizes of safe meals. Zn, Cu, Mn and Cr in these fish species reflected influence of the sewage waste. However, the non-carcinogenic risk evaluated through EDI, THQ, HI, and CR did not suggest any immediate health problem for the consumers.
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http://dx.doi.org/10.1016/j.envpol.2021.118089DOI Listing
September 2021

Selective binding of anions by rigidified nanojars: sulfate carbonate.

Org Biomol Chem 2021 Sep 15;19(35):7641-7654. Epub 2021 Sep 15.

Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, USA.

Selective binding and transport of highly hydrophilic anions is ubiquitous in nature, as anion binding proteins can differentiate between similar anions with over a million-fold efficiency. While comparable selectivity has occasionally been achieved for certain anions using small, artificial receptors, the selective binding of certain anions, such as sulfate in the presence of carbonate, remains a very challenging task. Nanojars of the formula [anion⊂{Cu(OH)(pz)}] (pz = pyrazolate; = 27-33) are totally selective for either CO or SO over anions such as NO, ClO, BF, Cl, Br and I, but cannot differentiate between the two. We hypothesized that rigidification of the nanojar outer shell by tethering pairs of pyrazole moieties together will restrict the possible orientations of the OH hydrogen-bond donor groups in the anion-binding cavity of nanojars, similarly to anion-binding proteins, and will lead to selectivity. Indeed, by using either homoleptic or heteroleptic nanojars of the general formula [anion⊂Cu(OH)(L2-L6)(pz)] ( = 26-31) based on a series of homologous ligands HpzCH(CH)CHpzH ( = 0-4; HL2-HL6), selectivity for carbonate (with L2 and with L4-L6/pz mixtures) or for sulfate (with L3) has been achieved. The synthesis of new ligands HL3, HL4 and HL5, X-ray crystal structures of HL4 and the tetrahydropyranyl-protected derivatives (THP)L4 and (THP)L5, synthesis and characterization by electrospray-ionization mass spectrometry (ESI-MS) of carbonate- and sulfate-nanojars derived from ligands HL2-HL6, as well as detailed selectivity studies for CO SO using these novel nanojars are presented.
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http://dx.doi.org/10.1039/d1ob01318aDOI Listing
September 2021

Gastrointestinal manifestations during COVID-19 virus infection: A Moroccan prospective study.

Arab J Gastroenterol 2021 Jul 30. Epub 2021 Jul 30.

Department of Gastroenterology, Military Hospital Mohammed V, Rabat, Morocco.

Background And Study Aims: Gastrointestinal manifestations are common during coronavirus disease (COVID-19) infection. They can occur before respiratory symptoms, resulting in a diagnostic delay and an increased risk of disease transmission. The current study reports major gastrointestinal manifestations as initial symptoms of COVID-19.

Patients And Methods: This prospective, descriptive, cross-sectional, and single-center study of 713 cases was conducted in a field hospital in Morocco over a 5-week period from June 21 to July 25, 2020.

Results: The average age of our patients was 31.95 years. Clinically, on admission, anorexia was the main symptom, present in 32.3% of patients. Gastrointestinal manifestations were present in 14.9% of patients, including watery diarrhea in 8.6% of cases, nausea and/or vomiting in 4.6% of cases, and abdominal pain in 1.6% of cases. Six hundred thirty-two patients were treated in accordance with one of the two therapeutic protocols recommended by the National Ministry of Health. The treatment-related effects that occurred in 61.4% of patients were primarily digestive in 55.3% of cases. In multivariate analysis, following adjustment of the studied parameters, only the presence of gastrointestinal manifestations (odds ratio [OR]: 1.478 confidence interval [CI]: 1.286-1.698; p < 0.001) and treatment side effects (OR = 1.069, CI: 1.020-1.119, p = 0.005) altered the rate of negative polymerase chain reaction (PCR) tests on day 10.

Conclusion: Gastrointestinal manifestations are common during COVID-19 and seem to be linked to a longer duration of disease. SARS-CoV-2 (the causative virus of COVID-19) can persist in the digestive tract, with the possibility of fecal-oral transmission. Therefore, hygiene is extremely important, especially handwashing and strict precautions when performing gastrointestinal endoscopy and handling stools from infected patients.
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http://dx.doi.org/10.1016/j.ajg.2021.07.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8321706PMC
July 2021

Auricular nerve stimulation using the NSS-2 BRIDGE device to reduce opioid requirement following laparoscopic Roux-en-Y gastric bypass.

Surg Obes Relat Dis 2021 Aug 12. Epub 2021 Aug 12.

Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.

Background: Evidence supports the use of complementary techniques to reduce pain and opioid use after surgery. The NSS-2 BRIDGE device (NBD; Innovative Health Solutions, Inc., Versailles, Indiana) modulates pain via stimulation of the nucleus of the auricular branch of the cranial nerves at the level of the brainstem and the limbic system.

Objective: To investigate the role of auricular nerve field stimulation for pain control following gastric bypass surgery.

Settings: U.S. academic medical center.

Methods: A total of 18 subjects were included. Subjects were divided in 2 groups: NBD group (n = 8) and a control group (n = 10). The NBD was placed following laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery in the recovery room. The effectiveness of NBD was assessed comparing the relative use of opioid consumption (oral morphine equivalents) and pain (0 = no pain to 10= worst possible pain) at 24 and 48 hours after surgery. In addition, the device tolerability (1-10) was assessed, with 8-10 considered excellent. Data were analyzed using unpaired t tests and presented as mean ± standard deviation. Alpha was set up at .1.

Results: Compared with the control group, the use of NBD was associated with a 60.2% reduction in oral morphine equivalents (38.15 vs 15.2 mg; P < .1) and a 28% reduction in pain (5.0 vs 3.6; P = .1) at 24 hours after surgery. The tolerability of NBD was reported to be excellent.

Conclusions: This report suggests that NBD may represent an interesting alternative to control perioperative pain and limit opioid use following bariatric surgery. This needs to be confirmed by a placebo-controlled, randomized study.
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http://dx.doi.org/10.1016/j.soard.2021.08.003DOI Listing
August 2021
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