3,140 research outputs found
BT-201: Investigation of the spider web for antibacterial activity
Spiders build their webs with a material called silk. Spider silk contain protein fiber that have many advantages and functions. One of them is to capture their prey such as flies, insects, and others. The needs on the research of antibacterial activity are important for human health because of importance of finding a new cure for some diseases that occur because of microorganisms. Some of the microorganisms, especially bacteria are becoming resistant to many antibacterial agents. The purpose of this new investigation was to determine if spider webs exhibit antibacterial properties. In order to determine antibacterial properties, the spider webs were extracted using different solvents such as methanol, ethanol, acetone, and water in different conditions (extraction time, and concentration used for optimization). These extracts were screened for antibacterial activity using disc
diffusion assay. Two bacteria were used in the antibacterial assay namely Bacillus subtilis, and Escherichia coli. The determination of spider webs exhibiting antibacterial properties was based, at least in this study, solely upon the definite appearance of inhibition zone around the well of plates. In screening, acetone solvent was shown the best for antibacterial
activity compare to other solvents with 10 mm of diameter of inhibition zone for Bacillus subtilis and 9 mm of diameter of inhibition zone for Escherichia coli. In optimization, the maximum inhibition zone on the Bacillus subtilis was 15 mm at a time of 48 hours and concentration of 0.035 g/ml. Meanwhile, the maximum diameter of inhibition zone on the Escherichia coli was 12 mm at a time of 48 hours and concentration of 0.035 g/ml. Therefore, this study showed that spider webs could be potential source of new antibacterial agents
Endovascular coiling versus surgical clipping in the treatment of ruptured anterior communicating artery aneurysm in Cairo University Hospitals
AbstractIntroductionAneurysmal Subarachnoid Hemorrhage (SAH) remains a devastating and often fatal form of stroke. The aneurysm is targeted for obliteration to prevent re-bleeding and to manage the possible complications from the event. Endovascular coiling has emerged as a less invasive alternative to conventional surgical clipping to treat aneurysms.Patients and methodsThis study was done prospectively in the Cairo University (Kasr El-Eini) hospitals to evaluate the outcome of both modalities used in the treatment of ruptured anterior communicating artery (Acom) aneurysm. 30 patients with Hunt and Hess grade I, II or III. were classified into two groups of microsurgical clipping (Endoscopic assistance used in five cases) and endovascular coiling.ResultsMortality rate was higher in the clipping group (26.7%) compared to the coiling group while recurrence rate was high in the coiling group (26.7%). Complications including hydrocephalus, hemiparesis and failed procedures occurred in (6.7%).ConclusionWe concluded that coiling is better for treating cases of ruptured Acom aneurysms being less invasive and achieving a favorable outcome compared to surgery. While Endoscope-Assisted Microsurgical Clipping (EAM) gives better control during clipping provided that a well-trained, competent and experienced neurosurgeon is available
Effect of Chicken Manure, N and P on Yield and Quality of Muskmelon (Cucumis melo var. Reticulatus Naud)
Two experiments were conducted at the National Institute for the Promotion of Horticultural Exports (NPÆ) Research Farm, Wad Medani, Sudan, during the summer of 20m and winter of 2000/2001, to study the effects of chicken manure, nitrogen and phosphorus on muskmelon yield and quality. The treatments were four levels of chicken manure (0, 4.5, 9 and 18t/ha), two levels of nitrogen (0 and 55kg N/ha) and two levels of phosphorus (0 and 55 kg P205/ha) arranged in a randomized complete block design with 3 replications. The results showed that muskmelon growth, yield and quality were significantly affected by chicken manure, N and P application. The most vigorous plant growth, the highest fruit yield and the largest fruits with best netting and highest total soluble solids were obtained by the application of 18 tons of chicken manure with 55kg N and 55kg
P205/ha
Effect of FSW Parameters on The Microstructure and Mechanical Properties of T-joints between Dissimilar Al-Alloys
The main purpose of this research is to develop T-joints between the aluminum AA 2024-T4 and AA 7075-T6 using friction stir welding. The effect of tool geometries, tool traveling speed, and rotational rate in the welded T-joints were investigated and discussed. Three different tools were used with different shoulder to pin ratios 3.28, 3.36, and 4.31. After optimization, the best tool dimension has used with the different rotational and welding speeds. Three tool traverse speeds of 50, 75, and 100 mm/min were used. Two rotation rates of 800 rpm and 1000 rpm were applied. After FSW, at a number of the above FSW parameters' combinations, macrostructure and microstructure analyses were done using optical microscopy. In order to have an insight into the mechanical properties, hardness measurements and tensile testing were carried out. Using small shoulder to pin ratio produced visually unacceptable T-joint. Opposite happened by using the tool with 4.31 of shoulder to pin ratio. Furthermore, the results showed sound T-welds with no obvious defects at high rotational rate of 1000 rpm with the two used traveling speeds. Asymmetric temperature distribution was observed between the two sides, advance side (AS) and retreating side (RS
Variation in physico-chemical properties of iron oxide pellets using bentonite with calcium hydroxide as binder
Bentonite and calcium hydroxide are the widely used binding materials in iron ore pelletizing plants. This investigation deals with studying the effect of using a mixture of both binders on the green, dry, and indurated iron oxide pellet properties. The binder mixtures consist of 0.4% bentonite, and varying percentage of calcium hydroxide (ranges from 0.5 to 4%). The objective is studying the possibility of partially replacing the expensive bentonite with cheap lime hydrate in pelletizing iron oxide. The results show that, on using binder mixture composed of 0.4% bentonite and 0.5% calcium hydroxide, a deterioration of the physico-chemical properties of the mill scale pellets was observed. Whereas, by increasing the percentage of calcium hydroxide in the binder mixture beyond 0.5%, a substantial enhancement in these properties was achieved
Recycling of manganese secondary raw material via cold-bond pelletizing process
Large quantities of fines were produced during the shipping, transportation, handling and storage of manganese ore sinter imported from different countries to Sinai Company for ferromanganese production. These fines are generally considered as valuable secondary raw materials. Hence, they have a potential to be recycled back to the submerged arc furnace after having been agglomerated. For agglomerates to be considered as feed materials for submerged arc furnace they must have sufficient room temperature strength. Cold-bonded pelletization process offers an economically attractive and environmentally viable method for achieving this. Ordinary Portland cement was used in this investigation for the purpose of producing a suitable coldbonded pellet from such fines. In this investigation, the effect of adding different percentages of Portland cement on the mechanical properties of both green and pellet dried at room temperature for 1, 3, 7, 14, and 28 days of normal curing were studied. The results revealed that, although the compressive strength of green pellets improved with the increase of the amount of cement added, retardation in pellet drop strength was reported. Whereas, the increase in both the cement content and time of drying leads to increase in the mechanical properties of pellets normally cured at room temperature. Pellets obtained with the addition of 9% cement shows reasonable mechanical properties to be charged in the submerged arc furnace. Ferromanganese alloy having a standard range composition was produced in a laboratory submerged arc furnace using such pellets
Cancer in Children at El Obeid Hospital, Western Sudan.
Background: Cancers form one of the major causes of death in children. They differ markedly from adult cancers in their nature, distribution and prognosis. Objectives: To determine the pattern of childhood cancer at El Obeid Hospital, Western Sudan. Patients and Methods: The records of all patients admitted with cancer aged 15 years and below tothe wards of El Obeid Hospital, Western Sudan over two years were studied. The cancers were classified according to the organs affected and then ranked in their order of relative frequency. The mean age, age range, gender and the relative frequency rates were calculated. Results: There were 40 newly diagnosed childhood cancer patients during the study period. Males were 29 patients (72.5%). The age ranged three months to 14 years. Leukaemias were the most common malignancy in both sexes, followed by bone tumours and then nephroblastoma.Conclusions: Cancers in children were seen at Western Sudan, and cases admitted to hospital only reflect the tip of the iceberg as many cases were directly referred to Oncology Hospitals. Establishment of a local radiation and isotopes centre is needed in this part of the country to provide oncology services and to integrate preventive programs.Key words: Acute lymphocytic leukaemia, osteosarcoma, nephroblastoma, Western Sudan
Photo-identification of Dugongs in Marsa Alam and Wadi El Gemal National Park, Egypt
1351-1358Using photo-identification techniques, 30 dugongs were recorded at the southern Egyptian Red Sea coast between December 2015 and October 2017, 16 at Marsa Alam and 14 at Wadi El Gemal National Park (WGNP). Males were recorded seven times more frequently than females and calves were also recorded. A Photo ID catalogue was prepared for the dugongs with records of their occurrence among sites. We confirmed the presence of particular dugong specific sites. Long- and short-distance movements within the study sites were recorded for eight different dugongs. This is the first study to document the number of dugongs in inshore areas of the Egyptian Red Sea coast. Further studies are recommended for offshore sites in WGNP for better documentation of this group of animals
Photo-identification of Dugongs in Marsa Alam and Wadi El Gemal National Park, Egypt
1351-1358Using photo-identification techniques, 30 dugongs were recorded at the southern Egyptian Red Sea coast between December 2015 and October 2017, 16 at Marsa Alam and 14 at Wadi El Gemal National Park (WGNP). Males were recorded seven times more frequently than females and calves were also recorded. A Photo ID catalogue was prepared for the dugongs with records of their occurrence among sites. We confirmed the presence of particular dugong specific sites. Long- and short-distance movements within the study sites were recorded for eight different dugongs. This is the first study to document the number of dugongs in inshore areas of the Egyptian Red Sea coast. Further studies are recommended for offshore sites in WGNP for better documentation of this group of animals
Application of a Novel Synergetic Control for Optimal Power Extraction of a Small-Scale Wind Generation System with Variable Loads and Wind Speeds
© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).The synergetic control technique (SCT) has the solution for understanding the symmetry inherent in the non-linear properties of wind turbines (WTs); therefore, they achieve excellent performance and enhance the operation of the WT. Small-scale WTs are efficient and cost-effective; they are usually installed close to where the generated electricity is used. This technology is gaining popularity worldwide for off-grid electricity generation, such as in rural homes, farms, small factories, and commercial properties. To enhance the efficiency of the WT, it is vital to operate the WT at its maximum power. This work proposes an efficient and fast maximum power point tracking (MPPT) technique based on the SCT to eradicate the drawbacks of the conventional methods and enhance the operation of the WT at the MPP regardless of wind speed and load changes. The SCT has advantages, such as robustness, simplified design, fast response, no requirement for knowledge of WT characteristics, no need for wind sensors or intricate power electronics, and straightforward implementation. Furthermore, it improves speed convergence with minimal steady-state oscillations at the MPP. The investigated configuration involves a wind-driven permanent magnet synchronous generator (PMSG), uncontrolled rectifier, boost converter, and variable load. The two converters are used to integrate the PMSG with the load. Three scenarios (step changes in wind speed, stochastic changes in wind speed, and variable electrical load) are studied to assess the SCT. The results prove a high performance of the suggested MPPT control method for a fast convergence speed, boosted WT efficacy, low oscillation levels, and applicability under a variety of environmental situations. This work used the MATLAB/Simulink program and was then implemented on a dSPACE 1104 control board to assess the efficacy of the SCT. Furthermore, experimental validation on a 1 kW Darrieus-type WT driving a PMSG was performed.Peer reviewe
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