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A coal rib monitoring study in a room-and-pillar retreat mine

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International Journal of Mining Science and Technology 2021年第1期31卷 127-135页

作者： Gamal rashed Khaled mohamed Robert Kimutis GCB/PMRD//NIOSH/CDC PittsburghPA 15236USA

The National Institute for Occupational Safety and Health(NIOSH)conducted a comprehensive monitoring program in a room-and-pillar mine located in Southern *** deformation and the stress change in an instrumented pillar were monitored during the progress of pillar retreat mining at two sites of different geological conditions and depths of *** main objectives of the monitoring program were to better understand the stress transfer and load shedding on coal pillars and to quantify the rib deformation due to pillar retreat mining;and to examine the effect of rib geology and overburden depth on coal rib *** instrumentation at both sites included pull-out tests to measure the anchorage capacity of rib bolts,load cells mounted on rib bolts to monitor the induced loads in the bolts,borehole pressure cells(BPCs)installed at various depths in the study pillar to measure the change in vertical pressure within the pillar,and roof and rib extensometers installed to quantify the vertical displacement of the roof and the horizontal displacement of the rib that would occur during the retreat mining *** outcome from the monitoring program provides insight into coal pillar rib support optimization at various depths and geological ***,this study contributes to the NIOSH rib support database in U.S coal mines and provides essential data for rib support design.

关键词： Coal rib performance Coal rib design Coal rib monitoring Coal rib failure Load transfer Retreat mining

Loading characteristics of mechanical rib bolts determined through testing and numerical modeling

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International Journal of Mining Science and Technology 2020年第1期30卷 17-24页

作者： Khaled mohamed Gamal rashed Zorica Radakovic-Guzina Centers for Disease Control National Institute for Occupational Safety and HealthPittsburghPA 15236USA ITASCA Consulting Group MinneapolisMN 55401USA

Underground coal mines use mechanical bolts in addition to other types of bolts to control the rib deformation and to stabilize the yielded coal *** research has been conducted to understand the performance of the mechanical bolts in coal *** from the National Institute for Occupational Safety and Health(NIOSH)conducted this work to understand the loading characteristics of mechanical bolts(stiffness and capacity)installed in coal ribs at five underground coal *** pull-out tests were performed in this study to define the loading characteristics of mechanical rib *** installation torques were applied to the tested bolts based on the strength of the coal seam.A typical tri-linear load-deformation response for mechanical bolts was obtained from these *** was found that the anchorage capacity depended mainly on the coal *** for modeling mechanical bolts have been developed using the tri-linear load-deformation *** outcome of this research provides essential data for rib support design.

关键词： Coal rib Mechanical bolt Conventional bolt Tension bolt Point-anchored bolt Rib support Pull-out test Numerical modeling FLAC3D

A NEW CONCEPT AND EXHIBITION PROGRAM FOR THE EGYPTIAN MUSEUM IN CAIRO

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Journal of Ancient Civilizations 2018年第1期33卷 41-82页

作者： mohamed Gamal rashed Damietta University

1. IntroductionIn parallel to the ongoing plans and anticipated opening of the Grand Egyptian Museum （GEM） and the National Museum of Egyptian Civilization （NMEC）,1 the Egyptian Museum in Cairo （EMC） will need t... 详细信息

关键词：国家博物馆埃及开罗展览

Preliminary rib support requirements for solid coal ribs using a coal pillar rib rating(CPRR)

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International Journal of Mining Science and Technology 2021年第1期31卷 15-22页

作者： Khaled mohamed Mark Van Dyke Gamal rashed Morgan MSears Robert Kimutis National Institute for Occupational Safety and Health Pittsburgh Mining Research DivisionPittsburghPA 15236USA

Researchers from the National Institute for Occupational Safety and Health(NIOSH)are developing a coal pillar rib rating(CPRR)technique to measure the integrity of coal *** CPRR characterizes the rib composition and evaluates its impact on the inherent stability of the coal *** CPRR utilizes four parameters:rib homogeneity,bedding condition,face cleat orientation with respect to entry direction,and rib *** these parameters are measurable in the field.A rib data collecting procedure and a simple sheet to calculate the CPRR were *** developed CPRR can be used as a rib quality mapping tool in underground coal mines and to determine the potential of local rib instabilities and support requirements associated with overburden *** calculations were conducted for 22 surveyed solid coal ribs,mainly composed of coal *** on this study,the rib performance was classified into four categories.A preliminary minimum primary rib support density(PRSD)line was obtained from these surveyed *** sample cases are presented that illustrate the data collection form and CPRR calculations.

关键词： Coal rib stability Rib support design Coal pillar rib rating Rib quality mapping CPRR Coal classification

Safety and efficacy of posterior sub-Tenon＇s carboplatin injection versus intravitreal melphalan therapy in the management of retinoblastoma with secondary vitreous seeds

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International Journal of Ophthalmology(English edition) 2018年第3期11卷 445-455页

作者： Azza mohamed Ahmed Said mohamed Gamil Al Hazem Omar rashed Anwaar Mahmoud Rady Department of Ophthalmology Faculty of Medicine Ain Shams University Cairo 11566 Egypt Oncology and Radiation Medicine Department Faculty of Medicine Ain Shams University Cairo 11566 Egypt

AIM： To evaluate the safety and efficacy of posterior sub-Tenon＇s carboplatin injection compared to intravitreal melphalan injection in the management of retinoblastoma （RB） with secondary vitreous seeds. The outcome measures were vitreous seeds regression, need for other treatment modalities to achieve ocular salvage and treatment side effects. METHODS： A prospective interventional comparative nonrandomized study included RB eyes developed secondary vitreous seeds during the period of follow up. They subdivided into two groups： study group Ⅰ where posterior sub-Tenon＇s carboplatin （20 mg/2 mL） was injected and study group Ⅱ where intravitreal melphalan （20 μg/0.1 mL） was injected. The injections repeated every 2-4wk. RESULTS： Thirty-three eyes were included in the study. Seventeen eyes （16 patients） in study group Ⅰ and 16 eyes （16 patients） in study group Ⅱ. Ten eyes （30.3%） were completely salvaged following local chemotherapies, Ocular salvage was 23.5% following posterior sub-Tenon＇s carboplatin injection versus 37.5% following intravitreal melphalan raised to 47.1% and 75% with addition of external beam radiotherapy （EBR） with no statistically significant difference between the study groups （P=0.16）. A statistically significant correlation was found between ocular salvage rate and type of vitreous seeds either dust, spheres and clouds （r=0.42, P=-0.015） and eyes harbor new solid tumor growth （r=0.35, P=0.045）. The mean and median follow up periods following local chemotherapy injections were 2.0y in the study group Ⅰand 2.37y in the study group Ⅱ. Few complications were reported： periorbital edema in all eyes and ocular motility disturbances in 13 eyes （76.5%） following posterior sub-Tenon＇s carboplatin injection. Vitreous hemorrhage developed in 2 eyes （12.5%） and localized retinopathy in 5 eyes （31.25%） following intravitreal melphalan. ~ CONCLUSION： Local chemotherapy for treatment of RB with secondary vitreous seeds is safe and can salvage 30.3% of eyes

关键词： intravitreal melphalan posterior sub-Tenon'scarboplatin retinoblastoma secondary vitreous seeds

Coal rib response during bench mining: A case study

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International Journal of Mining Science and Technology 2018年第1期28卷 107-113页

作者： Morgan M.Sears John Rusnak Mark Van Dyke Gamal rashed Khaled mohamed Michael Sloan Ground Control Branch NIOSH Pittsburgh Mining Research Division

In 2016, room-and-pillar mining provided nearly 40% of underground coal production in the United *** the past decade, rib falls have resulted in 12 fatalities, representing 28% of the ground fall fatalities in *** coal *** of these 12 fatalities(75%) have occurred in room-andpillar *** objective of this research is to study the geomechanics of bench room-and-pillar mining and the associated response of high pillar ribs at overburden depths greater than 300 *** paper provides a definition of the bench technique, the pillar response due to loading, observational data for a case history, a calibrated numerical model of the observed rib response, and application of this calibrated model to a second site.

关键词： Deep cover Bench mining Thick seam Retreat mining Rib response Rib support

Geochemistry of lamprophyres associated with uranium mineralization, Southeastern Desert, Egypt

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Chinese Journal Of Geochemistry 2007年第4期26卷 356-365页

作者： mohamed E. Ibrahim mohamed M. El-Tokhi Gehad M. Saleh Mamdouh A. Hassan mohamed A. rashed Nuclear Materials Authority P. O. Box 530 El Maadi Cairo Egypt Geology Deprtment Faculty of Science United Arab Emirates University United Arab Emirates

Two brecciated shear zones (NNW-SSE) are found crosscutting cataclastic rocks. The cataclastic rocks (3.0 km2) occupy the core of the granitic pluton and enclose a roof pendant of mafic-ultramafic rocks. The NNW-SSE-extending lamprophyre dykes vary in thickness from 0.5 m to 1 m and up to 800 m long, cutting the cataclastic rocks and are composed mainly of plagioclases, amphiboles, relics of pyroxenes and K-feldspar phenocrysts embedded in fine-grained groundmass. They are characterized as being peraluminous, calc-alkaline in composition (chemical trap) and enriched in calcite, sulfide and P2O5. The lamprophyres were affected by hydrothermal alteration (chlorite-carbonate alteration) while the cataclastic rocks were affected by diagenetic alteration (K-feldspar-albite alteration). Uranium mineralization is the product of hydrothermal events and has been investigated by X-ray diffraction (XRD) and environmental scanning electron microscopy (ESEM), involving primary uranium minerals (U3O8) and secondary uranium minerals (uranophane and beta-uranophane, kasolite, torbernite, autonite and meta-autonite) in addition to U- bearing minerals (astrocyanite, betafite and fergusonite). The presence of different mineral parageneses associated with clay minerals indicates that the lamprophyres were subjected to acidic and alkaline mineralizing solutions. Moreover, the U-Zr/U, U-Ce/U values show negative correlations, confirming U-enrichment in both cataclastic rocks and shear zones while the Th-eU/eTh, Th-Zr/Th and Th-Ce/Th values show negative correlations, indicating that the U-bearing solutions are rich in Th in the cataclastic rocks only.

关键词：碎裂岩石剪切区域煌斑岩热液蚀变埃及西南地区沙漠地带

Pyrrolidine dithiocarbamate and saxagliptin ameliorate ulcerative colitis in rats

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Asian Pacific Journal of Tropical Biomedicine 2019年第9期9卷 373-380页

作者： Berween Mahmoud Elmahmoudy Mai A.Abd El Fattah mohamed F.Elyamany Laila A.rashed Pharmacology and Toxicology Department Faculty of PharmacyCairo UniversityCairoEgypt Biochemistry and Molecular Biology Department Faculty of MedicineCairo UniversityEgypt

Objective: To evaluate the antioxidant, immunomodulatory and anti-inflammatory activities of pyrrolidine dithiocarbamate and saxagliptin in rats with thioacetamide-induced ulcerative colitis. Methods: Animals were orally administered with a vehicle, sulfasalazine(500 mg/kg), pyrrolidine dithiocarbamate(100 mg/kg), and saxagliptin(10 mg/kg) for two weeks. Ulcerative colitis was induced by a single intrarectal instillation of thioacetamide on day 8. Colon samples were collected to assess mitogen-activated protein kinase(MAPK), phosphorylated extracellular signal-regulated kinase(ERK), c AMP response element-binding protein(CREB), interleukin-12(IL-12), caspase-3, β-defensin, inducible nitric oxide synthase(i NOS) and glucagon like peptide-1(GLP-1). Moreover, histopathological examination was performed. Results: Rats treated with thioacetamide caused increases in colonic MAPK, phosphorylated ERK, CREB, caspase-3, IL-12, β-defensin, i NOS, as well as decreases in body weight and GLP-1. In addition, distortion of colonic structure was found by histopathological examination. Pyrrolidine dithiocarbamate and saxagliptin mitigated colitis severity by improving body weight decrease and GLP-1, and reducing colonic MAPK, phosphorylated ERK, CREB, caspase-3, IL-12, β-defensin and i NOS. Conclusions: Pyrrolidine dithiocarbamate and saxagliptin are efficient against thioacetamide induced colitis through improving inflammatory and oxidative changes.

关键词： Ulcerative colitis Inflammatory mediators Oxidative stress Pyrrolidine dithiocarbamate Saxagliptin Thioacetamide

Heart Failure Prediction in Athletic Heart Remodeling among Long Distance Runners

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World Journal of Cardiovascular Diseases 2022年第1期12卷 1-10页

作者： Hossam abdel Aleem Shaheen Manal Ahmed mohamed Fatma Hasan abdel Basset Mostafa Hamed rashed Neethu Betty Theruvan Soad A. Mosbah Department of Cardiac Technology College of Applied Medical Sciences Imam Abdulrahman Bin Faisal University Dammam City Kingdom of Saudi Arabia Department of Biochemistry National Heart Institute Giza Egypt Department of Physical Sport Sohar University Sohar Oman

Background: Physical activity has a cardinal role in preventing and treating cardiovascular diseases. Understanding the changes that occur to the cardiac muscle in athletes is still doubtful whether it is only an adaptation to exercise or a concealed pathological condition. Most of these changes are well documented in apparently healthy heart and characterized by cardiac enlargement with Brady-arrhythmias specially individuals participating in long distance runners with exercise capacity without signs of cardiovascular disease. Methods: The study searched the subclinical myocardial necrosis by comparing two groups of young marathon runners, both groups were chosen from Al Gizera youth center in January 2018. First group included adults above the age of 18 years and ran for 12 km. and the second was under 18 years and ran for about 8 km. Both groups were volunteered for this study. They are monitored carefully with blood pressure, heart rate and respiratory rate and their blood samples were collected pre- and post-race immediately for assessment of cardiac markers NTproBNP, Galectin-3 and cTnI. Results: All cardiac markers were elevated post exercise compared to that achieved in pre-exercise regardless age of athletes. Also, pre-exercise adult results were higher in galectin-3 and cTnI but not in proBNP while there is no difference in the acute response in both groups. These results revealed micro cardiac necrosis due to long run exercise with possible bad prognosis. Conclusions: It is important to develop risk assessment and prediction methods for screening the young athletes and consider the term athletic heart as a subclinical disorder rather than physiological adaptation.

关键词： Athletes Exercise Phidippides Cardiomyopathy Remodeling