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Antimicrobial activity of metal-substituted cobalt ferrite nanoparticles synthesized by sol-gel technique

Particuology 2018年第5期16卷 141-151页

作者： A.H.Ashour ahmed I.E1-Batal M.I.A.Abdel Maksoud Gharieb s.el-sayyad sh.Labib E.Abdeltwab M.M.el-Okr Materials science Laboratory Radiation Physics Department.National Center for Radiation Research and TechnologyAtomic Energy AuthorityCairoEgypt Drug Microbiology Laboratory Drug Radiation Research DepartmentNational Center for Radiation Research and TechnologyAtomic Energy Authority CairoEgypt Nuclear Chemistry Department Hot Laboratories CenterAtomic Energy AuthorityCairoEgypt Physics Department Faculty of Science (Girls Branch)Al-Azhar UniversityCairo.Egypt Physics Department.Faculty of science (Boys Branch) Al-Azhar UniversityCairoEgypt

Metal-substituted cobalt ferrites [MxCo(1-x)Fe2O4(M=Zn,Cu,Mn;x=0.0,0.25,0.5,and 0.75)]were synthesized via a sol-gel *** ferrite structures were confirmed by X-ray diffraction, Fourier transform infrared spectroscopy,scanning electron microscopy,surface analysis using the Brunauer-Emmett-Teller method,and energy-dispersive X-ray *** activity of these ferrites against selected pathogenic microbes was *** structures remained cubic spinel phases after substitution of *** strongly influenced the microstructure and homoge- neous grain *** particle size of the ferrites increased linearly with increase in their annealing *** surface area of zinc cobalt ferrite nanoparticles (ZCFO)was 52.56m^2/g,the average pore size was 1.84nm,and pore volume was 0.136mL/*** ferrites showed antimicrobial activity toward all pathogens *** these,the most powerful was ZCFO,showing zones of inhibition of 13.0mm against Bacillus subtilis and staphylococcus aureus and 12.0mm against Candida ***-irradiated ZCFO nanoparticles (150.0kGy)maintained higher antimicrobial activity than non-irradiated particles,e.g. being active toward *** (16.0mm).ZCFO is proposed as a candidate material for industrial and biomedical purposes.

关键词： Antibacterial Antifungal Zone of inhibition Zinc cobalt ferrite nanoparticles Gamma irradiation

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Exploitation of the antibacterial,antibiofilm and antioxidant activities of salvadora Persica(Miswak)extract

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Journal of Bioresources and Bioproducts 2023年第1期8卷 59-65页

作者： Gamal M.el-sherbiny ahmed Mohamed Gazelly Mohammed H.sharaf saad A.Moghannemm shehata M.E Mahmoud K.A.Ismail Ahmad s.el-Hawary Botany and Microbiology Department Faculty of Science(Boys)Al-Azhar UniversityCairo 11884Egypt

The salvadora persica(***)*** stick,usually known as miswak,is still being em-ployed as an oral hygiene agent for plaque and gingivitis *** study aims to assess the antibacterial,antibiofilm,antioxidant,and phytochemical profile of *** *** ***-sica was purchased from a local market,grinded and extracted with petroleum *** disk dif-fusion,microdilution,and micro-plate assays were performed to evaluate the antibacterial and an-tibiofilm activities of the prepared extract at different concentrations against𝛽-lactam resistance streptococcus *** radical scavenging 2,2-diphenyl-1-picrylhydrazyl(DPPH)and stable radical cationic chromophore,2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate)(ABTs)methods were used to determine their antioxidant *** and spectrometric analyses were performed using gas chromatography-mass(GC-Ms)*** minimum inhibitory concentration(MIC)of *** extract against𝛽-lactam resistance streptococcus species ranged from 6.25 to 12.5 mg/*** maximum suppression of biofilm formation by *** extract was observed at MIC with a percentage of 68.66%,against streptococcus *** *** ex-tract exhibited antioxidant activity with IC 50 of 20μg/mL and 35μg/mL from DPPH and ABTs,*** phytochemical characterization showed the presence of 22 compounds with ma-jor compounds;benzyl isothiocyanate(36.21%)and n-hexadecanoic acid(27.62%).The *** extract exhibited antibacterial activity against𝛽-lactam resistant streptococcus species,showing a promising natural alternative that could be a treatment option.

关键词： β-lactam resistance streptococcus species s.persica extract Antibacterial Antibiofilm Antioxidant GC-Ms analysis

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Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling systems

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structural Durability & Health Monitoring 2025年第1期19卷 77-103页

作者： sabrina Meddah sid ahmed Tadjer Abdelhakim Idir Kong Fah Tee Mohamed Zinelabidine Doghmane Madjid Kidouche Applied Automation Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of electrical and electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria electrical Engineering Department Mohamed Boudiaf University of M’silaM’sila28000Algeria Department of Civil and Environmental Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building Materials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is *** study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm to the system’s components since they are difﬁcult to be detected and controlled in real *** study investigates the dynamic interactions of these vibrations,speciﬁcally in their high-frequency modes,usingﬁeld data obtained from measurement while ***ﬁndings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem *** obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control ***,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect ***,by exploiting theseﬁndings,the assessment of structural resilience in rotary drilling systems can be ***,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efﬁciency of rotary drilling systems in the petroleum industry.

关键词： Rotary drilling systems mechanical vibrations structural durability dynamic interaction analysis ﬁeld data analysis

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Is the urinary kidney injury molecule an optimum biomarker for early detection of obstructive nephropathy? An experimental study

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Current Urology 2024年第4期18卷 312-317页

作者： ahmed s.el-hefnawy Mona A el-Hussiny ahmed M.A Ibrahim Khadiga M Ali Mohammed A Atwa Nashwa Barakat Mohamed Alhefnawy ahmed A shokeir Urology Department Urology and Nephrology CenterFaculty of Med/c/neMansouraEgypt Clinical Pathology Department Faculty of MedicineMansouraEgypt Clinical Pathology Department Student HospitalMansouraEgypt Pathology Department Faculty of MedicineMansouraEgypt Research Laboratory Department Urology and Nephrology CenterMansoura UniversityMansouraEgypt Faculty of Medicine Benha UniversityBenhaEgypt

Objectives To evaluate the urinary kidney injury molecule-1(KIM-1)as a predictor for early detection of acute kidney injury in cases with obstructive nephropathy in an animal model and to correlate urinary KIM-1 with the progress of obstructive nephropathy on a histopathological *** and methods Three models of obstruction were induced in 90 male rats:unilateral partial ureteral obstruction with a normal contra-lateral kidney,with nephrectomy of a contralateral kidney(solitary kidney),and bilateral partial ureteral *** group was further divided into 2 subgroups;the sham-group(10 rats)and the disease group(20 rats).serum creatinine,blood urea nitrogen,and urinary KIM-1 were collected on days 0,7,and *** were sacrificed on the 7th and 14th day for histopathological examination of the obstructed *** By the end of first week,there was a significant rise of all biomarker levels in all groups when compared with basal ***,biomarker levels at the 14th day were significantly higher than those obtained at the 7th *** urinary KIM-1 level was not detected in the baseline *** of urinary KIM-1 showed a significant rise in all models ranging from 22 to 85 fold at the 7th day and even higher levels at the 14th *** examination confirmed the presence of different forms of tubular *** Urinary KIM-1 is significantly elevated in obstructive *** an elevation might be advantageous in the early diagnosis and subsequent early intervention of cases with partial ureteral obstruction.

关键词： Biomarker Injury Kidney Kidney injury molecule Nephropathy Obstruction Uropathy

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Human Effects on Tabounsou’s Coastal Ecosystem and the Matoto-Conakry Case study of sustainable Management Practices

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Journal of Environmental science and Engineering(A) 2025年第1期14卷 43-52页

作者： Daouda Konate ahmed Guisse Yamoussa Bangoura Ousmane II Camara sekou ahmed Bangoura Department of Fisheries and Aquaculture Higher Institute of Veterinary Sciences and Medicine of DalabaBP09 Dalaba+224Guinea Conakry Rogbanèscientific Research Center BP:1516Conakry+224Republic of Guinea Boussoura National Center for Fisheries sciences BP1515 Conakry+224Guinea

Humans have always engaged with their surroundings and the ecology in which they ***,during the industrial age,this contact has been more intense and has had a substantial impact on environment and *** example,overexploitation of natural resources,mining,pollution,and deforestation are all elements that negatively affect biodiversity and natural *** studies have been conducted to evaluate the damage caused,despite the significant uncontrolled pressure from human ***,maintaining its environment is essential to the survival of coastal ***:This study’s goal was to evaluate how human activity affected Tabounsou’s coastal ecology in order to suggest remedial actions for sustainable *** following was the methodological approach used:executive consultation and archival analysis;stakeholder survey(locals,farmers,salt producers,fishers,and loggers);inventory of species;anthropogenic activity inventory;evaluation of how human activity affects aquatic life in the research region;suggestion and action for sustainable management;Outcome:Executive consultation indicated that the main issues are:construction projects that reduce the estuary’s surface area;agricultural practices such as woodcutting and salt farming;the rise in resource exploitation;noncompliance with fisheries laws;and the catching of young ***-three percent of fisherman ditch their nets on the coast after using them,but only seventeen percent burn *** a 75%frequency rate,the same survey indicates that most fisherman fish around the *** the Tabounsou area,according to loggers’survey,68%of the wood cut is Rhizophora,24%is Avicennia,and 8%is *** fish stocks,representing nine families and nine species,were identified by the species *** 18%and 15%,respectively,the actors most frequently capture the species Pseudotolithus.elongatus and Arius *** to a poll of 30 farmers,90%of them apply fertilizer to the

关键词： Coastal environment mitigation measures sustainable management.

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Three-dimensional printing of biomaterials for bonetissue engineering: a review

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Frontiers of Materials science 2023年第2期17卷 1-43页

作者： ahmed el-Fiqi Glass Research Department Advanced Materials Technology and Mineral Resources Research InstituteNational Research CentreCairo 12622Egypt

Processing biomaterials into porous scaffolds for bone tissueengineering is a critical and a key step in defining and controlling their physicochemical,mechanical,and biological *** such as polymers are commonlyprocessed into porous scaffolds using conventional processing techniques,e.g.,***,these traditional techniques have shown unavoidable limitations andseveral *** instance,tissue-engineered porous scaffolds with a complexthree-dimensional(3D)geometric architecture mimicking the complexity of theextracellular matrix of native tissues and with the ability to fit into irregular tissue defectscannot be produced using the conventional processing techniques.3D printing hasrecently emerged as an advanced processing technology that enables the processing ofbiomaterials into 3D porous scaffolds with highly complex architectures and tunableshapes to precisely fit into irregular and complex tissue defects.3D printing providescomputer-based layer-by-layer additive manufacturing processes of highly precise andcomplex 3D structures with well-defined porosity and controlled mechanical propertiesin a highly reproducible ***,3D printing technology provides anaccurate patient-specific tissue defect model and enables the fabrication of a patientspecifictissue-engineered porous scaffold with pre-customized properties.

关键词： 3D printing biomaterial ink printability 3D printing technique 3D printed scaffold bone tissue engineering

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sol-gel synthesis,properties and protein loading/delivery capacity of hollow bioactive glass nanospheres with large hollow cavity and mesoporous s.ell

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Frontiers of Materials science 2022年第3期16卷 145-157页

作者： ahmed el-FIQI Glass Research Department National Research CentreCairo 12622Egypt

Hollow nanospheres exhibit unique properties and find a wide interest in several potential applications such as drug ***,novel hollow bioactive glass nanospheres(HBGn)with large hollow cavity and large mesopores in their outer s.ells were synthesized by a simple and facile one-pot ultrasound assisted sol-gel method using PEG as the core ***,the produced HBGn exhibited large hollow cavity with ~43 nm in diameter and mesoporous s.ell of ~37 nm in thickness and 7 nm pore size along with nanosphere size around 117 *** confirmed the presence of si and Ca elements at the surface of the HBGn outer ***,HBGn showed high protein loading capacity(~570 mg of Cyto c per 1 g of HBGn)in addition to controlled protein release over 5 *** also demonstrated a good in vitro capability of releasing calcium(Ca^(2+):170 ppm)and silicate(siO_(4)^(4-):78 ppm)ions in an aqueous medium over 2 weeks under physiological-like *** in vitro growth of bone-like hydroxyapatite nanocrystals was exhibited by HBGn during the soaking in sBF.A possible underlying mechanism involving the formation of spherical aggregates(coils)of PEG was proposed for the formation process of HBGn.

关键词： bioactive glass hollow nanosphere hollow cavity mesoporous s.ell soft-template ultrasound assisted sol-gel synthesis therapeutic protein delivery

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Energy Efficiency of a solar Green Building Using Bio-sourced Materials for Indoor Temperature and Humidity Optimization

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Energy Engineering 2025年第1期122卷 41-62页

作者： soumiaMounir Youssef Maaloufa Abdelhamid Khabbazi elinaMohd Husini Nurul syalaAbdul Latip YakubuAminuDodo Rime elHarrouni MinaAmazal Asma souidi Malika Atigui ahmed Aharoune National school of Architecture Agadir New Complex Ibn ZohrAgadirBP 20732Morocco EMDD CERNE2DUniversity of Mohammed V in RabatEst SaleSaleBP 227Morocco Thermodynamics and Energetics Laboratory Faculty of ScienceIbn Zohr UniversityAgadirBP 8106Morocco Faculty of Built Environment University Sains Islam MalaysiaNilaiBP 71800Malaysia Architectural Engineering Department Najran UniversityNajranBP 1988Saudi Arabia The Centre of scientific and Engineering Research Najran UniversityNajranBP 1988Saudi Arabia Euro-Mediterranean school of Architecture Design and UrbanismEuro-Mediterranean University of FezFezBP 51Morocco

A clean environment with low carbon emissions is the goal of research on the development of green and sustainable buildings that use bio-sourced materials in conjunction with solar energy to create more sustainable *** is particularly true in Africa,where there aren’t many studies on the *** current study suggests a 90 m^(2) model of a sustainable building in a dry climate that is movable to address the issue of housing in remote areas,ensures comfort in harsh weather conditions,uses solar renewable resources—which are plentiful in Africa—uses biosourced materials,and examines how these materials relate to temperature and humidity control while emitting minimal carbon *** order to solve the topic under consideration,the work is split into two sections:numerical and experimental *** TRNsYs and Revit,the suggested prototype building is examined numerically to examine the impact of orientation,envelope composition made of bio-sourced materials,and carbon *** a hygrothermal investigation,experiments are conducted to evaluate this prototype’s ***,an examination of the photovoltaic system’s production,consumption,and several scenarios used tomaximize battery life is included in the *** the biosourcedmaterial achieves a thermal transmittance of 0.15(W.m^(-2).K^(-1)),the results demonstrate an intriguing finding in terms of *** value satisfies the requirements of passive building,energy autonomy of the dwelling,and injection in-network with an annual value of 15,757 ***,compared to the literature,the heating needs ratio is 6.38(kWh/m^(2).an)and the cooling needs ratio is 49(kWh/m^(2).an),both of which are good *** to international norms,the inside temperature doesn’t go above 26℃,and the humidity level is within a comfortable range.

关键词： Bio-sourced materials energy sustainability green architecture built environment

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LEO satellite clock analysis and prediction for positioning applications

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Geo-spatial Information science 2022年第1期25卷 14-33页

作者： Kan Wang ahmed el-Mowafy school of Earth and Planetary sciences Curtin UniversityPerthAustralia

The positioning service aided by low Earth orbit(LEO)mega-cons.ellations has become a hot topic in recent *** achieve precise positioning,accuracy of the LEO clocks is important for single-receiver *** bridge the gap between the applicable time of the clock products and the time of positioning,the precise LEO clocks need to be predicted over a certain period depending on the sampling interval of the clock *** study discusses the prediction errors for periods from 10 s to 1 h for two typical LEO clock types,*** ultra-stable oscillator(UsO)and the oven-controlled crystal oscillator(OCXO).The prediction is based on GNss-determined precise clock estimates,where the clock stability is related to the GNss estimation errors,the behaviors of the oscillators themselves,the systematic effects related to the environment and the relativistic effects,and the stability of the time *** on real data analysis,LEO clocks of the two different types are simulated under different conditions,and a prediction model considering the systematic effects is *** to a simple polynomial fitting model usually applied,the proposed model can significantly reduce the prediction errors,*** about 40%-70%in simulations and about 5%-30%for real data containing different miss-modeled *** both clock types,short-term prediction of 1 min would result in a root mean square error(RMsE)of a few centimeters when using a very stable time *** RMsE amounts to about 0.1 m,when a typical real-time time reference of the national center for space studies(CNEs)real-time clocks was *** long-term prediction of 1 h,the RMsE could range from below 1 m to a few meters for the UsOs,depending on the complexity of the miss-modeled *** OCXOs,the 1 h prediction could lead to larger errors with an RMsE of about 10 m.

关键词： LEO clock prediction UsO OCXO relativistic effects

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Magnetoresistive properties of Ni-doped La_(0.7)sr_(0.3)MnO_3 manganites

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Rare Metals 2016年第7期35卷 551-558页

作者： ahmed Mohamed ahmed Abd el-Moez ahmed Mohamed Medhat Abdelrady Abdellateef Hassan ahmed Abd el-Ghanny Physics Department Faculty of ScienceSohag University

Lao.7sr0.3Mnl_xNixO3 （x = 0, 0.025, 0.050 and 0.075） ceramics were prepared by the conventional solid-state reaction method. The partial substitution of Mn by Ni2＋ leads to a decrease in cell volume as well as a structural transition from the rhombohedral to the orthorhombic structure. Ni2＋ doping increases the electrical resistivity, decreases the semiconductor-metal transition temperature （Tms） and relatively enhances the room temperature magnetoresistance （MR）, especially in x = 0.025 and around Tins. With respect to conduction mechanism, the small polaron hopping （sPH） and the variable range hopping （VRH） models were used to ex- amine conduction in the semiconducting region.

关键词： Manganites X-ray diffraction structure electrical resistivity Magnetoresistance

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