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mineralogy and geochemistry of fine-grained Dahab stream sediments, Southeastern Sinai, Egypt: emphasis on the intergrowths of Fe–Ti oxides

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Acta Geochimica 2021年第6期40卷 871-894页

作者： Adel A.Surour ahmed.m.a.el-kammar Ebtisam H.Arafa Hala m.Korany Petroleum and mining Geology Faculty of SciencesGalala University43511 New Galala CityEgypt Department of Geology Faculty of ScienceCairo UniversityGiza 12613Egypt

mineralogical and geochemical characteristics of stream sediments collected from 30 stations in the Dahab-Wadi Kid area(southeastern Sinai,Egypt)are *** studied sediments contain considerable amounts of heavy minerals,including abundant Fe–Ti oxides,with up to 25.94%index figure that measures the relative abundance of heavy minerals to light *** of the sediments and nature of Fe–Ti oxide intergrowths,in addition to some non-opaque heavy minerals,indicate multiple provenances with contributions from a variety of Neoproterozoic mafic to felsic *** amounts of heavy minerals are derived from schists that belong to the so-called Wadi Kid volcanosedimentary *** to the considerable contribution of the felsic intrusions represented by within-plate granites,the sediments are enriched in REE-bearing minerals(e.g.,monazite,cerianite,La-cerianite and allanite),V-bearing thorite,zircon,and a ZrO_(2) *** majority of Fe–Ti oxides are derived from the mafic intrusions,and they show evidence of pre-,syn-and post-depositional phases of alteration and formation of *** to the geochemical signature of the bulk silt fraction,there is remarkable enrichment of LREEs with distinct negative Eu anomaly,and this supports dominance of a provenance dominated by felsic intrusions(i.e.,the A-type within-plate granite and associated pegmatites).Also,the felsic provenance is responsible for slight abnormality of ∑PU+Th content(up to~37 ppm)and few anomalous samples bear uraniferous zircon and Ce-type *** present paper sheds light on the fertility of the Dahab stream sediments in some economic minerals for possible future exploitation,not for gold only,but for potential REEbearing minerals that are needed for a wide spectrum of modern technological industries.

关键词： Dahab stream sediments Silt fraction Fe-Ti oxides Textural variations Rees enrichment

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Summary of the current guidelines for managing iatrogenic colorectal perforations and the evolving role of endoluminal vacuum therapy

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World Journal of Clinical Cases 2025年第6期13卷 1-8页

作者： ahmed Tawheed Ibrahim Halil Bahcecioglu mehmet Yalniz mubin Ozercan Ali Cagri Oral mohamed el-Kassas Department of Endemic medicine Faculty of MedicineHelwan UniversityCairo 11795Egypt Department of Gastroenterology Firat UniversityElazig 23119Türkiye Liver Disease Research Center College of MedicineKing Saud UniversityRiyadh 7805Saudi Arabia

Colonoscopy represents a safe procedure that is widely used in medical practice either to diagnose or treat various gastrointestinal *** the last few years,the incidence rate of perforations in colonoscopic procedures has increased,especially in therapeutic *** recent advancements in endoscopic techniques and gastrointestinal tumoral resection procedures such as endoscopic mucosal resection,endoscopic full-thickness resection,and endoscopic submucosal dissection(ESD)could be a risk factor for this increased *** incidence rate of mortality of serious colonoscopic perforations is 7.1%.The management plan for these perforations starts with conservative treatment in mild cases,endoscopic closure,and surgical management in severe ***,endoluminal vacuum therapy was found to be effective in the management of colorectal perforations and this has been reported in multiple case *** editorial provides an overview of the current guidelines for the management of iatrogenic colorectal *** insights are from the perspectives of endoscopists and *** also present a management algorithm based on the guidelines of the European Society of Gastrointestinal Endoscopy,the American Gastroenterological Association,and the World Society of Emergency *** also discussed in brief the use of endoluminal vacuum therapy in colorectal perforations.

关键词： Colon Rectum Iatrogenic colonic perforation Colonoscopy Guidelines Endovacuum Endolumical vacuum therapy Endoscopic 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 shell

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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 shells 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 shell 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 shell soft-template ultrasound assisted sol-gel synthesis therapeutic protein delivery

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Nanosecond pulse and dual-wavelength Q-switched 1.5 μm fiber laser using mAX phase Cr2TiAlC2 saturable absorber

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Optoelectronics Letters 2025年第1期21卷 7-12页

作者： ahmed Shakir AL-HITI Hiba HASSAN Department of electrical Engineering Faculty of Engineering University of Anbar Department of Laser and Optoelectronics Engineering University of Technology-Iraq

We demonstrated a new type of mAX phase material, chromium titanium aluminum carbide（Cr2TiAlC2） polymer film, to generate a passively Q-switched erbium-doped fiber laser（EDFL）. The film thickness was measured to be around 45 μm, which was fabricated using the embedding method with polyvinyl alcohol（PVA） polymer as hoster. The saturable absorber（SA） film demonstrates a dual-wavelength passively Q-switched EDFL which operates at 1 531 nm and 1 560.19 nm, respectively. The Q-switching pulse duration could be varied from 2.46 μs to 770 ns, while the repetition rate varied from 92.76 kHz to 106.6 kHz with an increasing input pumping range from 154 mW to 300 mW. The maximum output power and pulse energy of 15.05 mW and 141.18 nJ were obtained at the maximum input power of 300 mW, respectively.

关键词： Saturable absorbers

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Vascular endothelial growth factor:a double-edged sword in the development of white matter lesions

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Neural Regeneration Research 2025年第1期20卷 191-192页

作者： Narek manukjan Daniel Fulton Zubair ahmed Wmatthijs Blankesteijn Sébastien Foulquier Department of Pharmacology and Toxicology Maastricht UniversityMaastrichtThe Netherlands CARIm-School for Cardiovascular Diseases Maastricht UniversityMaastrichtThe Netherlands Neuroscience and Ophthalmology Institute of Inflammation and AgeingUniversity of BirminghamEdgbastonBirminghamUK Centre for Trauma Sciences Research University of BirminghamEdgbastonBirminghamUK mHeNs-School for mental Health and Neuroscience Maastricht UniversityMaastrichtThe Netherlands Department of Neurology Maastricht University Medical CenterMaastrichtThe Netherlands

As the population ages,the burden of age-related diseases becomes ***,over 55 million people suffer from dementia worldwide,with Alzheimer’s disease being the most common ***,it is becoming clearer that underlying vascular pathology such as cerebral small vessel disease(cSVD)may be a more detrimental cause for dementia(Cuadrado-Godia et al.,2018).It is estimated that 10%-30%of the elderly population and 35%-90%of all dementia patients exhibit signs of *** term cSVD refers to pathology affecting the small vessels of the brain,which can lead to lacunar cerebral infarcts,enlarged perivascular spaces,and cortical hemorrhages(Cuadrado-Godia et al.,2018).CSVD is often associated with cognitive decline,gait problems,and dementia(Cuadrado-Godia et al.,2018).

关键词： pathology becoming white

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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-constellations 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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Spirulina platensis extract improves the production and defenses of the common bean grown in a heavy metals-contaminated saline soil

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Journal of Environmental Sciences 2023年第7期129卷 240-257页

作者： mostafa m.Rady ahmed S.elrys Eman Selem ahmed A.A.mohsen Safaa m.A.I.Arnaout ahmed H.el-Sappah Khaled A.el-Tarabily el-Sayed m.Desoky Botany Department Faculty of AgricultureFayoum UniversityFayoum 63514Egypt College of Tropical Crops Hainan UniversityHaikou 570228China Soil Science Department Faculty of AgricultureZagazig UniversityZagazig 44511Egypt Botany and microbiology Department Faculty of ScienceZagazig UniversityZagazig 44511Egypt Horticulture Department Faculty of AgricultureZagazig UniversityZagazig 44511Egypt Botany Department Faculty of AgricultureZagazig UniversityZagazig 44511Egypt Genetics Department Faculty of AgricultureZagazig UniversityZagazig 44511Egypt Department of Biology College of ScienceUnited Arab Emirates UniversityAl-Ain 15551United Arab Emirates Khalifa Center for Genetic Engineering and Biotechnology United Arab Emirates UniversityAl-Ain 15551United Arab Emirates Harry Butler Institute Murdoch UniversityMurdoch 6150Australia

Plants have to cope with several abiotic stresses,including salinity and heavymetals(Hms).Under these stresses,several extracts have been used as effective natural biostimulants,however,the use of Spirulina platensis(SP)extract(SPE)remains *** effects of SPE were evaluated as soil addition(SA)and/or foliar spraying(FS)on antioxidant defenses and Hms content of common bean grown in saline soil contaminated with ***(40 or 80 mg SPE/hill added as SA or 20 or 40 mg SPE/plant added as FS)or integrative(SA+FS)applications of SPE showed significant improvements in the following order:SA-80+FS-40>SA-80+FS-20>SA-40+FS-40>SA-40+FS-20>SA-80>SA-40>FS-40>FS-20>***,the integrative SA+FS with 40 mg SP/plant was the most effective treatment in increasing plant growth and production,overcoming stress effects and minimizing contamination of the edible *** significantly increased plant growth(74%–185%)and yield(107%–227%)by enhancing net photosynthetic rate(78.5%),stomatal conductance(104%),transpiration rate(124%),and contents of carotenoids(60.0%),chlorophylls(49%–51%),and NPK(271%–366%).These results were concurrent with the marked reductions in malondialdehyde(61.6%),hydrogen peroxide(42.2%),nickel(91%–94%),lead(80%–9%),and cadmium(74%–91%)contents due to the improved contents of glutathione(87.1%),ascorbate(37.0%),andα-tocopherol(77.2%),and the activities of catalase(18.1%),ascorbate peroxidase(18.3%),superoxide dismutase(192%),and glutathione reductase(52.2%)as reinforcing ***,this most effective treatment is recommended to mitigate the stress effects of salinity and Hms on common bean production while minimizing Hms in the edible part.

关键词： Antioxidant defense system Biostimulants Heavy metals microalgae extracts Saline soil Soil pollution

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Biological silicon nanoparticles improve Phaseolus vulgaris L. yield and minimize its contaminant contents on a heavy metals-contaminated saline soil

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Journal of Environmental Sciences 2021年第8期33卷 1-14页

作者： mohamed T.el-Saadony el-Sayed m.Desoky ahmed m.Saad Rania S.m.Eid Eman Selem ahmed S.elrys Department of Agricultural microbiology Faculty of AgricultureZagazig UniversityZagazig 44511Egypt Botany Department Faculty of AgricultureZagazig UniversityZagazig 44511Egypt Biochemistry Department Faculty of AgricultureZagazig UniversityZagazig 44511Egypt Agricultural Botany Department Faculty of AgricultureBenha University13736Egypt Botany and microbiology Department Faculty of ScienceZagazig University44511Egypt Soil Science Department Faculty of AgricultureZagazig University44511ZagazigEgypt

The synthesis of biological silicon nano-particles(Bio-Si-NPs)is an eco-friendly and lowcost *** is no study focusing on the effect of Bio-Si-NPs on the plants grown on saline soil contaminated with heavy *** this study,an attempt was made to synthesis Bio-Si-NPs using potassium silica florid substrate,and the identified Aspergillus tubingensis Am11 isolate that separated from distribution systems of the potable water.A twoyear field trial was conducted to compare the protective effects of Bio-Si-NPs(2.5 and 5.0 mmol/L)and potassium silicate(10 mmol/L)as a foliar spray on the antioxidant defense system,physio-biochemical components,and the contaminants contents of Phaseolus vulgaris *** on saline soil contaminated with heavy *** findings showed that all treatments of Bio-Si-NPs and potassium silicate significantly improved plant growth and production,chlorophylls,carotenoids,transpiration rate,net photosynthetic rate,stomatal conductance,membrane stability index,relative water content,free proline,total soluble sugars,N,P,K,Ca2+,K+/Na+,and the activities of peroxidase,catalase,ascorbic peroxidase and superoxide oxide *** of Bio-Si-NPs and potassium silicate significantly decreased electrolyte leakage,malondialdehyde,H2 O2,O2·-,Na+,Pb,Cd,and Ni in leaves and pods of Phaseolus vulgaris *** to ***-Si-NPs were more effective compared to potassium *** of Bio-Si-NPs at the rate of 5 mmol/L was the recommended treatment to enhance the performance and reduce heavy metals content on plants grown on contaminated saline soils.

关键词： Bean Silicon Nano-silicon Aspergillus tubingensis Am11 Salinity Heavy metals

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