1,371 research outputs found

    Shuttle/spacelab MMAP/electromagnetic environment experiment phase B definition study

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    Progress made during the first five months of the Phase B definition study for the MMAP/Electromagnetic Environment Experiment (EEE) was described. An antenna/receiver assembly has been defined and sized for stowing in a three pallet bay area in the shuttle. Six scanning modes for the assembly are analyzed and footprints for various antenna sizes are plotted. Mission profiles have been outlined for a 400 km height, 57 deg inclination angle, circular orbit. Viewing time over 7 geographical areas are listed. Shuttle interfaces have been studied to determine what configuration the antenna assembly must have to be shared with other experiments of the Microwave Multi-Applications Payload (MMAP) and to be stowed in the shuttle bay. Other results reported include a frequency plan, a proposed antenna subsystem design, a proposed receiver design, preliminary outlines of the experiment controls and an analysis of on-board and ground data processing schemes

    A Simple Algorithm for Sidelobe Cancellation in a Partially Adaptive Linear Array

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    The far-field lobes of the edge elements of a uniformly excited linear array are nearly equal in width to the sidelobes of the array itself, and hence the edge elements are ideal for cancellation of specific sidelobes of the pattern. This supports the concept of partial adaptivity using only the edge elements. This technique is suitable for real-time implementation because only the edge elements require direct control whereas the inner elements are controlled by PROM’s. Other advantages are that the nulls produced specifically by control of the edge elements are deep and wide. Also the main beam gain is not much affected by the sidelobe cancellation

    Fast cancellation of sidelobes in the pattern of a uniformly excited array using external elements

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    A method for wide null steering in the pattern of a uniformly excited linear array that utilizes the edge elements of the array is investigated. Simpler and faster algorithms for sidelobe reduction are introduced which use one or two external edge elements. Comparisons between these methods are held. Sample results are given

    Wavelet phase evaluation extended to digital speckle patterninterferometry

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    A wavelet algorithm developed to improve metrology based on electronic speckle pattern intérferometry (ESPI) is presented. The wavelet algorithm is based on the calculation of the continuous wavelet transform of a modulated speckle correlation fringes .The Paul wavelet is used , the extraction of the maximum scales of the modulus of the wavelet transform leads simply to the phase gradient distribution. The advantage of the method is to provide phase distribution, with a high accuracy, from a single interferogram without unwrapping step.A wavelet algorithm developed to improve metrology based on electronic speckle pattern intérferometry (ESPI) is presented. The wavelet algorithm is based on the calculation of the continuous wavelet transform of a modulated speckle correlation fringes .The Paul wavelet is used , the extraction of the maximum scales of the modulus of the wavelet transform leads simply to the phase gradient distribution. The advantage of the method is to provide phase distribution, with a high accuracy, from a single interferogram without unwrapping step

    Aneurysmal bone cyst primary - about eight pediatric cases: radiological aspects and review of the literature

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    The aneurysmal bone cyst is a pseudotumoral lesion that can take several aspects. This is a rare lesion representing 1% of bone tumors. It appears usually during the first 30 years of life. The pathogenesis is that of a process of "dysplasia/hyperplasia", favored by a circulatory deficiency and hemorrhage within the lesion and the phenomena of osteoclasis. The objective of this work is to illustrate with analysis, the specific forms and atypical aneurysmal bone cyst which often pose a diagnostic challenge requiring radiological investigation with histological confirmation. We report eight pediatric cases of aneurysmal cysts collected over a period of 3 years, 3 boys and 5 girls. All patients had standard radiographs. MRI was performed in three patients. The diagnosis was confirmed histologically. The atypia has been in the seat: fibula (1 case), metaphyseal (2 cases), diaphyseal (4 cases) and metatarsal (1 case). Aneurysmal bone cyst is a rare benign tumor with predilection to the metaphysis of long bones. Atypical forms even fewer are dominated by the atypical seat.Key words: Bone cyst, aneurysm, osteolytic lesio

    Pharmacy students' attitudes toward pharmaceutical care in Qatar

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    Objectives: The study objectives were to investigate Qatar pharmacy students' attitudes toward pharmaceutical care (PC), to identify the factors that influence their attitudes, and to recognize their perceived barriers for PC provision. Methods: A cross-sectional and online survey of Qatar pharmacy students was conducted. Results: Over 4 weeks, 46 surveys were submitted (88% response rate). All respondents agreed that the pharmacist's primary responsibility is to prevent and resolve medication therapy problems. Most respondents believed that PC provision is professionally rewarding and that all pharmacists should provide PC (93% and 91% of respondents, respectively). Highly perceived barriers for PC provision included lack of access to patient information (76%), inadequate drug information sources (55%), and time constraints (53%). Professional year and practical experience duration were inversely significantly associated with four and five statements, respectively, out of the 13 Standard Pharmaceutical Care Attitudes Survey statements, including the statements related to the value of PC, and its benefit in improving patient health and pharmacy practitioners' careers. Conclusion: Qatar pharmacy students had positive attitudes toward PC. Efforts should be exerted to overcome their perceived barriers.Scopu

    Peristaltic Transport of a Physiological Fluid in an Asymmetric Porous Channel in the Presence of an External Magnetic Field

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    The paper deals with a theoretical investigation of the peristaltic transport of a physiological fluid in a porous asymmetric channel under the action of a magnetic field. The stream function, pressure gradient and axial velocity are studied by using appropriate analytical and numerical techniques. Effects of different physical parameters such as permeability, phase difference, wave amplitude and magnetic parameter on the velocity, pumping characteristics, streamline pattern and trapping are investigated with particular emphasis. The computational results are presented in graphical form. The results are found to be in perfect agreement with those of a previous study carried out for a non-porous channel in the absence of a magnetic field

    Plasma Adrenomedullin level in Egyptian children and Adolescents with type 1 diabetes mellitus: relationship to microvascular complications

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    <p>Abstract</p> <p>Background</p> <p>Adrenomedullin (AM) is known to be elevated in different clinical situations including diabetes mellitus (DM), but its potential role in the pathogenesis of vascular complications in diabetic children and adolescents is to be clarified. Hence, the study aimed at assessment of plasma adrenomedullin levels in children and adolescents with type 1 DM and correlation of these levels with metabolic control and diabetic microvascular complications (MVC).</p> <p>Methods</p> <p>The study was performed in the Diabetes Specialized Clinic, Children's Hospital of Ain Shams University in Cairo, Egypt. It included 55 diabetic children and adolescents (mean age 13.93 ± 3.15 years) who were subdivided into 40 with no MVC and 15 with MVC. Thirty healthy subjects, age-and sex- matched were included as control group (mean age 12.83 ± 2.82 years). Patients and controls were assessed for glycosylated hemoglobin (HbA1c) and plasma adrenomedullin assay using ELISA technique.</p> <p>Results</p> <p>Mean plasma AM levels were significantly increased in patients with and without MVC compared to control group, (110.6 pg/mL, 60.25 pg/mL and 39.2 pg/mL respectively) (P < 0.01) with higher levels in those with MVC (P < 0.05). Plasma AM levels were positively correlated with both duration of diabetes (ρ = 0.703, P < 0.001) and glycemic control (HbA1c) (ρ = 0.453, P < 0.001).</p> <p>Conclusion</p> <p>Higher plasma AM levels in diabetics particularly in those with MVC & its correlation with diabetes duration and metabolic control may reflect the role of AM in diabetic vasculopathy in the pediatric age group.</p

    Erythropoietin mitigated thioacetamide-induced renal injury via JAK2/STAT5 and AMPK pathway

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    The kidney flushes out toxic substances and metabolic waste products, and homeostasis is maintained owing to the kidney efforts. Unfortunately, kidney disease is one of the illnesses with a poor prognosis and a high death rate. The current investigation was set out to assess erythropoietin (EPO) potential therapeutic benefits against thioacetamide (TAA)-induced kidney injury in rats. EPO treatment improved kidney functions, ameliorated serum urea, creatinine, and malondialdehyde, increased renal levels of reduced glutathione, and slowed the rise of JAK2, STAT5, AMPK, and their phosphorylated forms induced by TAA. EPO treatment also greatly suppressed JAK2, Phosphatidylinositol 3-kinases, and The Protein Kinase R-like ER Kinase gene expressions and mitigated the histopathological alterations brought on by TAA toxicity. EPO antioxidant and anti-inflammatory properties protected TAA-damaged kidneys. EPO regulates AMPK, JAK2/STAT5, and pro-inflammatory mediator synthesis
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