Dr Mohammed Mahmoud Youssif

The euglenatides are a family of hybrid polyketide-nonribosomal peptides produced by the unicellular algae Euglena gracilis. These compounds have antiproliferative activity against fungal pathogens and mammalian cancer cell lines. Analysis of E. gracilis extracts revealed that the algae produce not only the euglenatides, but also a corresponding family of analogs that have the same molecular weights as the euglenatides, but are lacking the characteristic triene chromophore. In comparison to the euglenatides, the activity of these analogs is greatly reduced in a mammalian cytotoxicity assay, indicating that the triene is critical to the biological activity of the euglenatides.

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The development of multifunctional materials capable of serving both as high-efficiency adsorbents and high-performance supercapacitors is a critical challenge for environmental and energy applications. In this study, a novel zeolitic imidazole framework-8/mycelial pellet (ZIF-8/MP) composite was successfully synthesized using a simple in-situ growth and staged adsorption process. The MP with its three-dimensional porous structure, served as a scaffold, facilitating the uniform distribution of ZIF-8 across the porous carbon matrix. The resulting ZIF-8 in the ZIF-8/MP composite demonstrated a remarkable adsorption capacity for Congo red (CR), with a maximum capacity of 1428.57 mg/g. The adsorption mechanism was attributed to electrostatic interactions, zinc coordination, hydrogen bonding, and π–π conjugation, as confirmed by FTIR, XPS, and DFT analyses. After adsorption, the carbonized ZIF-8/MP composite demonstrated outstanding supercapacitor performance, achieving a specific capacitance of 113.4 F/g at 1 A/g, and maintaining 93 % capacitance retention after 5000 charge/discharge cycles. Additionally, the ZIF-8/MP composite effectively reduced the toxicity of CR, as demonstrated by phytotoxicity assays, underscoring its potential for environmental remediation. This innovative approach provides an eco-friendly, easily separable, efficient, and practical multifunctional material for transforming hazardous waste into valuable resources for environmental detoxification and energy storage applications.

The development of multifunctional materials capable of serving both as high-efficiency adsorbents and high-performance supercapacitors is a critical challenge for environmental and energy applications. In this study, a novel zeolitic imidazole framework-8/mycelial pellet (ZIF-8/MP) composite was successfully synthesized using a simple in-situ growth and staged adsorption process. The MP with its three-dimensional porous structure, served as a scaffold, facilitating the uniform distribution of ZIF-8 across the porous carbon matrix. The resulting ZIF-8 in the ZIF-8/MP composite demonstrated a remarkable adsorption capacity for Congo red (CR), with a maximum capacity of 1428.57 mg/g. The adsorption mechanism was attributed to electrostatic interactions, zinc coordination, hydrogen bonding, and π–π conjugation, as confirmed by FTIR, XPS, and DFT analyses. After adsorption, the carbonized ZIF-8/MP composite demonstrated outstanding supercapacitor performance, achieving a specific capacitance of 113.4 F/g at 1 A/g, and maintaining 93 % capacitance retention after 5000 charge/discharge cycles. Additionally, the ZIF-8/MP composite effectively reduced the toxicity of CR, as demonstrated by phytotoxicity assays, underscoring its potential for environmental remediation. This innovative approach provides an eco-friendly, easily separable, efficient, and practical multifunctional material for transforming hazardous waste into valuable resources for environmental detoxification and energy storage applications.

Methacholine chloride (MCh), a hydrolyzable cholinergic agonist, is widely employed in bronchoprovocation tests for asthma diagnosis. However, the instability of MCh in aqueous solutions poses a major concern during the methacholine challenge test. To address this issue, the innovative ‘Green-Dip’ approach was developed for in-line potentiometric monitoring of MCh hydrolysis in inhalation solutions prepared for the challenge test. A portable, eco-friendly, and disposable screen-printed electrode (SPE) was designed and optimized to quantify MCh and monitor its hydrolytic degradation under varying pH conditions, enabling the determination of key kinetic parameters. The SPE was enhanced for improved selectivity, detection limit, and resistance to potential drift by incorporating calix[4]arene (CX4) as an ionophore within the ion-sensing membrane (ISM) and multiwalled carbon nanotubes (MWCNTs) as a transducing layer between the ISM and the electrode surface. The proposed sensor exhibited Nernstian behavior for MCh over a concentration range of 3.05 × 10−7 M to 1.00 × 10−2 M, with a detection limit of 8.91 × 10−8 M and a slope of 57.20 ± 0.33 mV/decade. It demonstrated excellent performance characteristics, including minimal potential drift (1.10 mV/h), a rapid response time (4 ± 1 s), and an extended operational lifetime of approximately 50 days. As part of the ‘Green-Dip’ approach and to enhance environmental sustainability, 2-methyltetrahydrofuran (MeTHF) was utilized as an eco-friendly alternative to tetrahydrofuran (THF) for dissolving the components of the ion-sensing membrane (ISM). The proposed sensor facilitated real-time monitoring of MCh hydrolysis, enabling the evaluation of pH and temperature effects, as well as the calculation of reaction rate constants, half-life, and activation energy. This cost-effective, eco-friendly in-line tool provides a reliable solution for assessing the stability of MCh solutions in methacholine challenge tests, addressing both analytical precision and environmental concerns.

Introduction: Dentin hypersensitivity is a painful dental issue known with a transient and intense pain, when the exposed dentin reacts to various stimuli. Bioactive glass and multiple types of lasers have been tested in treating dentin hypersensitivity. Yet, none have combined them together in occluding exposed dentinal tubules.Aim of the Study: The current study focused on evaluating the effect of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser with wavelength 2780 nm and bioactive glass nanoparticles paste either each alone or in combination with different sequences; on dentinal tubules closure.Methods: Forty healthy extracted premolar teeth were used for this study. They were distributed equally into a control group and 4 experimental groups. Control group: received no treatment. Nano-Bioactive glass group: treated with nano-bioactive glass paste only, Er,Cr:YSGG laser group: received laser irradiation only, Er,Cr:YSGG laser + nano-bioactive glass group: treated with nano-bioactive glass paste after laser irradiation. Nano-bioactive glass + Er,Cr:YSGG laser group: treated with nano-bioactive glass paste before laser irradiation. Dentin samples were evaluated morphologically by scanning electron microscope, with subsequent analysis of the mean diameter of dentinal tubules, and calcium and phosphorous analysis by energy dispersive X-ray spectroscopy.Results: Nano-bioactive glass + Er,Cr:YSGG laser group showed notably improved dentinal tubules closure in comparison to the other groups through scanning electron microscope imaging. The results were confirmed by the energy dispersive X-ray analysis which revealed the highest calcium and phosphorus weight %, in addition to recording the lowest mean diameter of dentinal tubules.Conclusion: The application of nano-bioactive glass and, Er,Cr:YSGG laser and the combination of both provided a satisfactory dentinal tubular closure. However, combining both nano-bioactive glass and Er,Cr:YSGG laser was found to be more efficient with superior results, rather than using each modality alone.

We report the optimized design and theoretical analysis of broadband omnidirectional mirrors made of silicon nanostructures. The design principle is based on regulating the electrochemical etching process of single-crystalline silicon substrates in an acidic solution using a train of sinusoidal current waveforms with tightly-spaced frequencies. The individual frequency of the etching current waveform is calibrated to produce a specific photonic band in the reflectance spectrum. A linear relationship is obtained between the frequency of the current signal and the resonant position of the photonic band. The frequency range of the etching waveform is selected to produce a broad photonic peak resulting from the bandgap overlap among multiple photonic bands associated with the individual frequency of each current signal. The transfer matrix method is utilized to calculate the angular reflectance spectra of the experimentally obtained omnidirectional mirrors for both transverse electric (TE) and transverse magnetic (TM) polarization of the incident light. Good agreement is found between the experimental and theoretical reflectivity spectra.

A gold nanoparticle/graphitic carbon nitride heterostructure nanocomposite was synthesized via an in-situ chemical reduction of Au3+ on the surface of graphitic carbon nitride and was applied for the non-invasive electrochemical detection of uric acid (UA) in human saliva. In this configuration, gold nanoparticles (Au-NPs) acted as highly active electrocatalytic sites, while graphitic carbon nitride (g-C3N4) served as a high-surface-area scaffold facilitating uniform nanoparticles dispersion and efficient electron transfer. Morphological and elemental characterization using scanning electron microscopy (SEM), High Resolution Transmission Electron Microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), BET analysis, and infrared spectroscopy (IR) confirmed the homogeneous distribution of Au-NPs anchored to the g-C3N4 sheets. Furthermore, electrochemical characterization was performed through electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Electrochemical measurements demonstrated that Au-NPs@g-C3N4/CPE generated significantly higher UA oxidation peak currents compared with bare CPE. Under optimized pH conditions, accumulation potential, and differential pulse parameters the sensor exhibited a well-defined linear calibration range 0.5–10.0 μM (r = 0.9943) with a detection limit of 0.31 μM uric acid. Selectivity tests in artificial saliva showed negligible signal deviations (≤ ±2 %) in the presence of common salivary interferents such as ascorbic acid, creatinine, and glucose. Spike and recovery experiments using actual saliva samples achieved recoveries of 95.56-98.27 % confirming high analytical accuracy in complex biological matrices. Furthermore, the electrode retained over 90 % of its initial response after 60 days of ambient storage indicating excellent stability. The synergistic integration of Au-NPs with g-C3N4 significantly enhanced catalytic activity, electron transport, and UA adsorption making the Au-NPs@g-C3N4/CPE a cost-effective, sensitive, and reliable platform for point-of-care UA monitoring in saliva for clinical diagnostics and health applications.

A gold nanoparticle/graphitic carbon nitride heterostructure nanocomposite was synthesized via an in-situ chemical reduction of Au3+ on the surface of graphitic carbon nitride and was applied for the non-invasive electrochemical detection of uric acid (UA) in human saliva. In this configuration, gold nanoparticles (Au-NPs) acted as highly active electrocatalytic sites, while graphitic carbon nitride (g-C3N4) served as a high-surface-area scaffold facilitating uniform nanoparticles dispersion and efficient electron transfer. Morphological and elemental characterization using scanning electron microscopy (SEM), High Resolution Transmission Electron Microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), BET analysis, and infrared spectroscopy (IR) confirmed the homogeneous distribution of Au-NPs anchored to the g-C3N4 sheets. Furthermore, electrochemical characterization was performed through electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Electrochemical measurements demonstrated that Au-NPs@g-C3N4/CPE generated significantly higher UA oxidation peak currents compared with bare CPE. Under optimized pH conditions, accumulation potential, and differential pulse parameters the sensor exhibited a well-defined linear calibration range 0.5–10.0 μM (r = 0.9943) with a detection limit of 0.31 μM uric acid. Selectivity tests in artificial saliva showed negligible signal deviations (≤ ±2 %) in the presence of common salivary interferents such as ascorbic acid, creatinine, and glucose. Spike and recovery experiments using actual saliva samples achieved recoveries of 95.56-98.27 % confirming high analytical accuracy in complex biological matrices. Furthermore, the electrode retained over 90 % of its initial response after 60 days of ambient storage indicating excellent stability. The synergistic integration of Au-NPs with g-C3N4 significantly enhanced catalytic activity, electron transport, and UA adsorption making the Au-NPs@g-C3N4/CPE a cost-effective, sensitive, and reliable platform for point-of-care UA monitoring in saliva for clinical diagnostics and health applications.

The 2024 outbreak of Highly Pathogenic Avian Influenza (HPAI) H5N1 in U.S. dairy cattle represents a significant change in the behavior of zoonotic influenza viruses. Previously, H5N1 was primarily an avian pathogen with limited infection in mammals. The emergence of clade 2.3.4.4b H5N1 in dairy herds across multiple states reveals the virus’s adaptation to mammalian hosts and highlights its potential for zoonotic transmission, raising important concerns for public health, veterinary medicine, and agriculture. The virus demonstrated unique tropism for mammary tissue, with high viral loads detected in milk. Genomic analysis identified mutations that enhance binding to mammalian receptors and facilitate systemic spread. Viral RNA was found in raw milk, posing food safety risks; however, standard pasteurization effectively inactivated the virus. Epidemiological data indicate the outbreak likely began with spillover from wild birds or contaminated fomites, followed by efficient local transmission within herds. Forty-one human cases linked to infected dairy operations were confirmed. The outbreak caused significant economic losses due to decreased milk production and trade restrictions. Although human-to-human transmission remains low, the zoonotic risk requires urgent attention. The 2024 HPAI H5N1 outbreak in U.S. dairy cattle highlights critical gaps in surveillance, biosecurity, and coordination across sectors. A One Health approach integrating veterinary, public health, and environmental efforts is essential. Recommendations include improved surveillance, stringent biosecurity measures, occupational safety protocols, focused research on viral evolution, and investment in diagnostics and vaccines. These actions are vital to reduce risks, protect public health, and ensure the sustainability of the dairy industry against future zoonotic influenza threats.

The major objective was to investigate the protective capabilities of endophytic bacterial strains isolated from a number of medicinal plant species towards Aspergillus spp. secured from the internal tissues of fungi-infected peanuts. Among 32 fungal isolates surveyed for mycotoxin production in various culture media (PDA, RBCA, YES, CA), 10 isolates qualitatively producing AFB1, besides 10 OTA-producers, were assayed by HPLC for quantitative toxin production. Aspergillus spp. isolate Be 13 produced an extraordinary quantity of 1859.18 μg mL−1 AFB1, against the lowest toxin level of 280.40 μg mL−1 produced by the fungus isolate IS 4. The estimated amounts of OTA were considerably lower and fell in the range 0.88–6.00 μg mL−1; isolate Sa 1 was superior, while isolate Be 7 seemed inferior. Based on ITS gene sequencing, the highly toxigenic Aspergillus spp. isolates Be 13 and Sa 1 matched the description of A. novoparasiticus and A. ochraceus, respectively, ochraceus, respectively, which are present in GenBank with identity exceeding 99%. According to 16S rRNA gene sequencing, these antagonists labeled Ar6, Ma27 and So34 showed the typical characteristics of Pseudomonas aeruginosa, Bacillus subtilis and Bacillus velezensis, respectively, with similarity percentages of 99–100. The plant growth-promoting activity measurements of the identified endophytes indicated the production of 16.96–80.00 μg/100 mL culture medium of IAA. Phosphate-solubilizing capacity varied among endophytes from 2.50 to 21.38 μg/100 mL. The polysaccharide production pool of bacterial strains ranged between 2.74 and 6.57 mg mL−1. P. aeruginosa Ar6 and B. velezensis successfully produced HCN, but B. subtilis failed. The in vitro mycotoxin biodegradation potential of tested bacterial endophytes indicated the superiority of B. velezensis in degrading both mycotoxins (AFB1-OTA) with average percentage of 88.7; B. subtilis ranked thereafter (85.6%). The 30-day old peanut (cv. Giza 6) seedlings grown in gnotobiotic system severely injured due to infection with AFB1/OTA-producing fungi, an effect expressed in significant reductions in shoot and root growth traits. Simultaneous treatment with the endophytic antagonists greatly diminished the harmful impact of the pathogens; B. velezensis was the pioneer, not P. aeruginosa Ar6. In conclusion, these findings proved that several endophytic bacterial species have the potential as alternative tools to chemical fungicides for protecting agricultural commodities against mycotoxin-producing fungi.