检索结果-南通市图书馆

Open Journal of Civil Engineering 2015年第1期5卷 131-138页

作者： Mohamed A. ahmed Yehia A. Hassanean Kamal A. Assaf Moustafa A. Shawkey Materials Science Lab. (1) Physics Department Faculty of Science Cairo University Giza Egypt Department of Civil Engineering Assiut University Assiut Egypt

Mn-Ferrite nanoparticles were prepared using citrate auto combustion method. The prepared sample was characterized by X-ray diffraction (XRD), HRTEM and BET to measure the particle diameter and the surface area of the prepared sample. The data of XRD clarified that the sample was formed in single phase spinel structure without any extra peaks indicating non-existence of any secondary phase. The HRTEM micrograph indicated that the particles were in an agglomerated state due to the absence of surfactant and high magnetic properties of Mn-Ferrite nanoparticles. The mechanical properties were measured at different ratios of nano-Ferrite to concrete. The obtained values of mercury intrusion porosimetry (MIP) indicated that the addition of Mn-Ferrite nanoparticles increased the compressive strength and decreased the total intrusion volume. This was due to the rapid consuming of Ca(OH)2 which was formed during hydration of Portland cement especially at early ages due to the high reactivity of MnFe2O4 nanoparticles. Moreover, MnFe2O4 nanoparticles recovered the particle packing density of the blended cement, leading to a reduced volume of pores in the cement paste.

关键词： Compressive Strength Concrete XRD HRTEM Reactivity

Investigation of the Phytochemicals, Antioxidant, and Antimicrobial Activity of the <i>Andrographis paniculata</i>Leaf and Stem Extracts

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Bioscience and Biotechnology 2017年第5期8卷 149-162页

作者： Shakil ahmed Polash Tanushree Saha Md. Sharif Hossain Satya Ranjan Sarker Department of Biotechnology and Genetic Engineering Faculty of Biological Sciences Jahangirnagar University Dhaka Bangladesh Department of Textile Engineering Dhaka University of Engineering and Technology Gazipur Bangladesh

Andrographis paniculata (Kalmegh) has been considered as a medicinal shrub and used as a medicinal plant in the remote areas of Bangladesh. A. paniculata leaf and stem extracts were prepared using the polar (i.e., water, and 70% ethanol) and nonpolar (i.e., hexane) solvents. The phytochemical contents, total phenol contents (TPC), antioxidant activity, and antibacterial activity of all the extracts of A. paniculata leaf and stem were investigated. Both the gram-positive (i.e., Bacillus subtillis) and gram-negative (i.e., E. coli, and Salmonella typhi) strains of bacteria were used for the antibacterial activity assay of the sample extracts. The ethanolic stem extracts contained the maximum amount of TPC when compared to that of the leaf extracts. However, the aqueous stem extracts had the highest free radical scavenging activity in vitro. The extracts prepared from A. paniculata stem showed better antibacterial activity against all the strains of bacteria (i.e., E. coli, S. typhi, and B. subtillis) when compared to that of the leaf extracts. More specifically, the aqueous stem extract showed superior antibacterial effect against E. coli, and B. subtillis, and the zones of inhibition were 21 mm, and 29 mm in diameter, respectively. On the other hand, the ethanolic stem extract showed the maximum antibacterial activity against S. typhi and the zone of inhibition was 8.15 mm. The minimum inhibitory concentration (MIC) value and IC50 value for all the A. paniculata extracts were ~0.05 μg/μL, and ~1 μg/μL, respectively.

关键词： Andrographis paniculata Total Phenol Content Antioxidant Antimicrobial Zone of Inhibition

Tensile Strength of Squeeze Cast Carbon Fibers Reinforced Al-Si Matrix Composites

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Minerals and Materials Characterization and Engineering 2011年第2期10卷 127-141页

作者： ahmed A. Moosa Kahtan K. Al-Khazraji Osama S. Muhammed Department of Production Engineering and Metallurgy University of Technology Baghdad Materials Engineering Department University of Technology Baghdad Iraq.

Squeeze casting is a pressure casting process in which molten metal is solidified under the direct action of a pressure. In squeeze casting, the relationship between the process parameters and the quality of the squeeze cast components is not fully understood;thus the need for more studies in this area of technology for better understanding of the process. The present work encompasses studying the effect of direct squeeze casting process parameters on the production of (3 and 20%) volume fraction carbon fibers (CF) reinforced Al-Si matrix composites. The evaluated process parameters are squeeze pressure in the range (7.5-53) MPa, die preheating temperature (100,200,300)°C, pouring temperature (700,780)°C, squeeze time (30 sec.), and delay time (5 sec.). The results show a good distribution of the matrix between the carbon fibers when using higher casting pressures of (38 and 53MPa), lower pouring temperature of (700°C) and lower die temperatures of (100 and 200°C). Increasing the carbon fibers volume fraction had led to increasing the tensile strength. The using of higher pressure (53MPa), lower pouring temperature (700°C), and lower die temperature (200°C) have increased the ultimate tensile strength of the CF/Al-Si composites to (183MPa) when compared to that of the nonreinforced alloy which was (168MPa) because of the increased bonding, decreased shrinkage defects and fibers degradation based on the results. Also, UTS is increased at P=38MPa, Tp=700°C, and Td=100°C.

关键词： Tensile Strength Squeeze Cast Carbon Fibers

First Cycle Neutrophil Count and Subsequent Chemotherapy Dose Delivery in Breast Cancer Patients Receiving Adjuvant Chemotherapy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Cancer Therapy 2014年第2期5卷 172-178页

作者： ahmed Ashour Gamal El-Husseiny Amr Abdel Aziz Waleed O. Arafat Department of Clinical Oncology and Nuclear Medicine Faculty of Medicine Alexandria University Alexandria Egypt

Background: Chemotherapy-induced neutropenia is a major dose-limiting toxicity of systemic cancer chemotherapy, and it is associated with substantial morbidity, mortality, and costs. The ability to predict the group of patients who are at high risk for neutropenic complications might help to reduce the morbidity due to febrile neutropenia and increase the likelihood of delivering full chemotherapy dose on time. In addition, hematopoietic growth factors could be administered to patients who need them and allow more efficient use of medical resources. Methods: The study included 120 female patients with breast cancer, treated in adjuvant setting with FAC chemotherapy regimen. Chemotherapy was delayed if the ANC was less than 1500 cells/μL on the planned first day of the cycle. Dose delays would be for 1 week. The chemotherapy dose was reduced if the patient experienced an episode of febrile neutropenia. Dose reductions usually consist of a 20% reduction in dosage of all chemotherapy drugs. Results: Out of the 120 patients in the study, 58 patients experienced neutropenic complications (febrile neutropenia or dose delayed) accounting for 48.3% of total sample size. In univariate analysis, there was statistically significant association between first cycle ANC nadir and neutropenic complication (p = 0.0001). There was also statistically significant association between pretreatment first cycle ANC (p = 0.001), pretreatment platelets count (p = 0.054), first cycle platelets count nadir (p = 0.041), number of involved lymph nodes (p = 0.031) and the occurrence of varies neutropenic complications. However, in multivariate analysis, ANC nadir was only the independent risk factor for occurrence of neutropenic. Conclusions: The first cycle absolute neutrophil counts nadir provides useful information on the risk of future neutropenia, febrile neutropenia and dose delay or reduction with estimated sensitivity and specificity, which were 64.5% and 77.6%, respectively. Other facto

关键词： Breast Cancer Chemotherapy Neutropenia

Study on Sesame Export for Sudan Based on Gravity Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Engineering and Technology 2017年第2期5卷 31-39页

作者： Mansour Yousif ahmed Adam Shiwei Xu Wen Yu Shengwei Wang Siek Darith Agricultural Information Institute Chinese Academy of Agricultural Sciences Beijing China Key Laboratory of Digital Agricultural Early-Warning Technology Ministry of Agriculture Beijing China

This study aimed to investigate the effect of social and economic differences between importer and exporter countries on trade flows of Sesame seed product. The analysis was carried out by estimating the gravity model. The sample covered a total of 14 countries for the period from 1997 to 2009. The results showed that the social and economic differences between countries have a significant and positive or negative effect on Sesame seeds trade. Furthermore, we found that the same language, distance and sesame production in export country have positive effect for the sesame export from Sudan.

关键词： Sesame Trade Gravity Model Sudan Partner Countries Policy

The Impact of Implementing the International Convention on the Control of Harmful Anti-fouling Systems in Ships （AFS Convention） on the Marine Environment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Shipping and Ocean Engineering 2016年第1期6卷 57-63页

作者： Capt. ahmed Saad Hassan Noufal Capt. Mohamed Hussein Nassar Hassan Arab Academy for Science Technology & Maritime Transport Alexandria 21913 Egypt

Marine fouling is the settlement and growth of a variety of marine organisms, such as bacteria, diatoms, protozoa and algae spores on structures immersed in seawater, such as ship＇s hulls, navigation buoys, and sonar equipment. Anti-fouling refers to material or systems used to prevent the accumulation of biological material on submerged surfaces. Bio-fouling results in higher fuel consumption and can also facilitate the transport of harmful NIS （Non-Indigenous Species）. Antifouling technologies incorporating biocides （e.g., Tributyltin） have been developed to prevent fouling. Their widespread use, however, raised concerns about their toxic effects on marine communities. The AFS Convention （International Convention on the Control of Harmful Anti-fouling Systems in Ships） is a 2001 IMO （International Maritime Organization） treaty, whereby states agree to ban the use of harmful anti-fouling paints and other anti-fouling systems that contain harmful substances. Particularly, the use of the organotinTributyltin is prohibited, since leaching of that chemical from the hulls of ships has been shown to cause deleterious effects on some sea creatures. Although the AFS Convention has entered into force, its full implementation has not yet been appropriately achieved. Most of the ratifying States have delegated the Classification Society to inspect their ships to ensure the implementation of the provisions of the Convention. Since painting ships takes place in dry docks, the full control falls in the hands of Classification Societies.

关键词： Anti-fouling environment Tributyltin organotins biocide.

Fore-Body Side Vortex of KVLCC2 at 30°Drift: A Trailing Vortex Resolved with DES and Compared to PIV Data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Fluid Dynamics 2019年第4期9卷 303-325页

作者： Dag-Frederik Feder Ivan Shevchuk ahmed Sahab Lukas Gerwers Moustafa Abdel-Maksoud FDS/TUHH Hamburg Germany

A hybrid RANS-LES approach is used to resolve the Fore-body Side Vortex (FSV) separating from the KVLCC2 hull at 30° drift angle and Reynolds number ReLoa ≈ 2.56e6. The performance of the DES approach is evaluated using a proper grid study. Besides, the following aspects of the CFD results are investigated: the resolution of turbulent energy, the prediction of instantaneous and time-averaged vortical structures, local flow features, the limiting streamlines and the evolution of the vortex core flow. New PIV data from wind tunnel experiments is compared to the latter. The results form a basis for future investigations in particular on the vortex interaction further downstream and the applicability of different kinds of turbulence models to trailing vortices like the FSV. Turbulence modelling is realised with the k-ω-SST-IDDES model presented in [1], the grids’ cell count is 6.4 M, 10.5 M and 17.5 M. Grid convergence of the time-averaged vortex core flow is observed. OpenFOAM version 1806 is used to carry out the simulations and snappyHexMesh to build the mesh.

关键词： KVLCC2 DES Hybrid RANS-LES PIV Trailing Vortex Drift

Quantitative Estimation of Gallic Acid as Biomarker in Lipitame Tablets by HPTLC Densitometry for Diabetic Dyslipidemia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Medicine 2014年第4期5卷 170-178页

作者： Sheeraz Siddiqui Khan Usmanghani Aqib Zahoor Zeeshan ahmed Sheikh Saleha Suleman Khan Faculty of Eastern Medicine Hamdard University Karachi Pakistan Research and Development Department Herbion Pakistan (Pvt.) Limited Karachi Pakistan

Lipitame is a poly herbal formulation comprised of Terminalia arjuna, Terminalia belerica, Commiphora mukul and Phyllanthus emblica. The formulation is investigated for its analysis evaluation. Biomarkers of three herbs such as Terminalia arjuna, Terminalia belerica, and Phyllanthus emblica have been already cited to contain gallic acid, which was qualitatively and quantitatively estimated. In the present study rapid and inexpensive qualification methods for the quality control of Terminalia arjuna, Terminalia belerica, Commiphora mukul and Phyllanthus emblica on thin layer chromatography (TLC) were developed and validated. The solvent system used was toluene:ethyl acetate:formic acid:methanol (12:9:4:0.5). The scanning of plate was performed linearly at 273 nm (absorption) by use of a TLC Scanner III CAMAG with a deuterium source, and the area of spots corresponding to Gallic acid standard was integrated. It was found that gallic acid has been found in the Lipitame tablets on HPTLC densitometry assessment compared with authentic gallic acid reference standard.

关键词： Lipitame Tablets Quantitative Estimation Densitometry Diabetic Dyslipidemia

Clinical Profile of Lymphatic Malformation from One Oral and Maxillofacial Center in Sudan

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Stomatology 2017年第8期7卷 345-352页

作者： Omar Amir El Hag Elneel ahmed Mohamed Ali Musadak Ali Karrar Osman OMF Surgery Gazira University Wad Medani Sudan OMF Surgery Faculty of Dentistry University of Khartoum Khartoum Sudan OMFs Section Dental Department King Faisal Specialist Hospital & Research Center Riyadh KSA

Background: Lymphatic malformations are developmental defects of the lymphatic system. They are frequently present at birth and are most commonly found in the head and neck regions. The aim of the study was to investigate the clinical presentation of head and neck Lymphatic malformations in relation to, age, gender, color and site of distribution. Methods: This is a retrospective descriptive study, where the record of the patient diagnosed as lymphatic malformation at the Department of Oral and Maxillofacial Surgery at Khartoum Teaching Dental Hospital, during the period of 2005 to 2008 where retrieved and analysed. Result: A cervicofacial lymphatic malformation was found more common in females than in males with a ratio of 11:9. The mean age was 14 ± 10 years, with lip and tongue being the most common sites, followed by the buccal mucosa in the intraoral site and neck in the posterior triangle was the most common site for extraoral site (30%). It was found that the bluish color was the commonest presenting color in oral lymphangioma followed by red pink color. Conclusion: Females are more affected than males, while infants and children were more affected than other age groups. The bulks of the patients were presented with soft swelling, blue to normal colour in the lip, neck and in the tongue. Further prospective studies are needed to evaluate the clinic picture and treatment outcome.

关键词： Lymphangioma Lymphatic Malformation Maxillofacial Tumor Sudan

Expression of pro-inflammatory genes （Pro-I） in A2A adenosine receptor （A2A） knockout （KO） mouse model of allergic asthma.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Expression of pro-inflammatory genes （Pro-I） in A2A adenos...