Radiation Patterns Account of a Circular Microstrip Antenna Loaded Two Annular

In this paper, theoretical study of circular microstrip antenna loaded two annular (CMSAL2AR) and calculation of the radiation pattern using principle equivalence with moment of method formulation of electromagnetic radiation in this these based on the bodies of revolution (BoR), which are generated by revolution a planar curve about an axis called axis of symmetry to solving the electric fields integral equation (EFIE) and magnetic field integral equation (MFIE). To find an unknown electric current density  on the conductor surface ,and both unknowns electric and magnetic density  current on the dielectric surface which are  responsible for the generation of far fields radiation in the space for the components (Eθ ,Eφ) ,the surface currents was represented by a set of basis functions that give the Fourier series because the body has a circular symmetry property and then select a set of weighted  functions to find a linear system by using.......

Designing a Microstrip Patch Antenna in Part of Ultra-Wideband Applications

في هذه الدراسة، أجريت دراسة محاكاة لتصميم هوائي شريطي مع رقعة مستطيلة لولبية جديدة والذي يُستخدم في تطبيقات النطاق الترددي العريض الفائق وباستخدام برنامج محاكاة التراكيب عالية التردد (high frequency structure simulator software (HFSS)) . تم استخدام شريحة عازلة بقيمة ثابت عزل يساوي 4.4 وارتفاع 2.10 ملم لتصميم الهوائي المقترح. أن أساس التصميم يستند على زيادة عرض النطاق الترددي ضمن الحزمة الترددية 6.63 - 10.93 كيكاهرتز من خلال زيادة مناطق الحافة للمشع والتي تؤثر إيجابًا على كفاءة الهوائي. أن هذا التصميم يجعل تكلفة تصميم الهوائي اقل من خلال تقليل مساحة المشع. لاحظنا أن عرض النطاق الترددي للهوائي في هذه الدراسة يزداد إلى 4.30 كيكاهرتز أو ما يعادل 61٪ مقارنةً بالنسبة 3.6٪ الناتجة عن الهوائي الشريطي المستطيل القياسي مع نفس أبعاد الهوائي المقترح. أن الهوائي المقترح حافظ على نسبة موجة الفولتية القياسية الواقفة (voltage standing wave ratio) وهي 1.09 عند التردد الرنيني  7.7  كيكاهيرتز، وعامل الفقد 27.07  ديسبل، وان قيمة الجزء الحقيقي والخيالي للممانعة هي 51.5  أوم و 3.3  أوم ، على الترتيب.In this work, a simulated study was carried out for designing a novel spiral rectangular patch of microstrip antenna that is used in ultra-wideband applications by using a high frequency structure simulator software (HFSS). A substrate with dielectric constant of 4.4 and height 2.10 mm (commercial substrate height available is about 0.8-1.575 mm) has been used for the design of the proposed antenna. The design basis for enhancing bandwidth in the frequency range 6.63 - 10.93 GHz is based on increasing the edge areas that positively affect the antenna's efficiency. This design makes the designed antenna cost less by reducing the area of the patch. It has been noticed that the bandwidth of the antenna under this study is increasing to 4.30 GHz or 61% compared with 3.6% for the standard rectangular microstrip antenna with the same dimensions of the proposed antenna. The antenna also maintains the voltage standing wave ratio of 1.09 at resonant frequency 7.07 GHz, return loss -27.07 dB, and the amount of impedance in real and imaginary parts 51.5Ω and 3.3Ω, respectively

Evolution of second trimester low implanted placenta to previa at term: a prospective cohort study

Background: The objective of this study is to identify the percentage of low implanted placenta (LIP) at second trimester of pregnancy and identify the risk factors of its persistence to placenta previa (PP) at term.Methods: Through a registered prospective cohort study conducted at tertiary hospital in Upper Egypt, authors screened all pregnant ladies comes to present facility for antenatal second trimester USG between 18-24 weeks gestation. All participants interviewed for detailed risk factors of placenta previa. Those diagnosed to have a LIP (≤1.5 cm from the internal os) had had TVS to confirm the exact distance between the lower edge of the placenta and the internal os. Serial USG had been done every 4 weeks up to delivery to measure the same distance. The primary outcome was the percentage of LIP at 18-24 weeks. Logistic regression analysis was performed to predict the risk factors for PP at term.Results: Through screening of 1000 pregnant lady, LIP had been identified in (52 cases) 5.2% of pregnant women between 18-24 weeks. This percentage dropped gradually to reach 1.3% at 36 weeks of gestation and at time of delivery. The logistic regression analysis demonstrated that the distance between the internal os and the lower edge of the placenta between 18-24 weeks was the single significant variable associated with PP at term (p<0.001, odds ratio 0.319, 95% CI 0.20-0.50). However, excluding the distance from the regression model demonstrated other risk factors as previous miscarriage, previous cesarean section (CS), and history of multiple pregnancies and history of previous PP.Conclusions: About 5.0% of pregnant women have LIP at the second trimester of pregnancy (18-24 weeks) and only 25.0 % of them remain placenta previa at term. A cut-off value of 10 mm between the internal os and the lower edge of the placenta is the most important predictor of development of PP

Novel Green Micro-Synthesis of Graphene-Titanium Dioxide Nano- Composites with Photo-Electrochemical Properties

Background: Graphene-Titanium dioxide nano-composite forms a very promising material in the field of photo-electrochemical research. Methods: In this study, a novel environment-friendly synthesis method was developed to produce well-distributed anatase nano-titanium dioxide spherical particles on the surface of graphene sheets. This novel method has great advantages over previously developed methods of producing graphenetitanium dioxide nanocomposites (GTNCs). High calcination temperature 650°C was used in the preparation of nano titanium dioxide, and chemical exfoliation for graphene synthesis and GTNC was performed by our novel method of depositing titanium dioxide nanoparticles on graphene sheets using a Y-shaped micro-reactor under a controlled pumping rate with minimal use of chemicals. Results: The physiochemical and crystallographic properties of the GTNC were confirmed by TEM, XRD, FTIR and EDX measurements, confirming process repeatability. Spherical nano-titanium dioxide was produced in the anatase phase with very high crystallinity and small particle diameters ranging from 9 nm to 25 nm, also the as prepared graphene (RGO) exhibited minimal flake folding and a high carbon content of 81.28% with a low oxygen-to-carbon atomic ratio of 0.172 and GTNCs produced by our novel method had a superior loading content, a homogeneous distribution and a 96.6% higher content of titanium dioxide particles on the graphene sheets compared with GTNCs prepared with the one-pot method. Conclusion: For its photoelectrochemical properties, chronoamperometry showed that GTNC sample (2) had a higher peak current of 60 μA compared with that of GTNC sample (1), which indicates that the separation and transfer of electron-hole pairs are better in the case of GTNC sample (2) and according to the LSV results, the generation of photocurrent in the samples can be observed through multiple on-off cycles, which indicates that the electrodes are stable and that the photocurrent is quite reversible

Crystal structure of ethyl 2-[2-((1E)-{(1E)-2-[2-(2-ethoxy-2-oxoethoxy)benzyl-idene]hydrazin-1-ylidene}methyl)phen-oxy]acetate

NSF–MRI grant No. 1228232 for the purchase of the diffractometer and Tulane University for support of the Tulane Crystallography Laboratory are gratefully acknowledged.Peer reviewedPublisher PD

Nosocomial blood stream infection in intensive care units at Assiut University Hospitals (Upper Egypt) with special reference to extended spectrum β-lactamase producing organisms

<p>Abstract</p> <p>Aim</p> <p>This study investigated the nosocomial blood stream infection (BSI) in the adult ICUs in Assiut university hospitals to evaluate the rate of infection in different ICUs, causative microorganisms, antimicrobial resistance, outcome of infection, risk factors, prevalence of extended spectrum B-lactamase producing organisms and molecular typing of <it>Klebsiella pneumoniae </it>strains to highlight the role of environment as a potential source of nosocomial BSI.</p> <p>Methods</p> <p>This study was conducted over a period of 12 months from January 2006 to December 2006. All Patients admitted to the different adult ICUs were monitored daily by attending physicians for subsequent development of nosocomial BSI. Blood cultures were collected from suspected patients to detect the causative organisms. After antimicrobial susceptibility testing, detection of ESBLs was conducted among gram negative isolates. Klebsiella pneumoniae isolates were tested by PCR to determine the most common group of B-lactamase genes responsible for resistance. Klebsiella pneumoniae isolates from infected patients and those isolated from the environment were typed by RAPD technique to investigate the role of environment in transmission of infection.</p> <p>Results</p> <p>The study included 2095 patients who were admitted to different ICUs at Assiut University Hospitals from January 2006 to December 2006. Blood samples were collected from infected patients for blood cultures. The colonies were identified and antibiotic sensitivities were performed. This study showed that the rate of nosocomial BSI was 75 per 1000 ICU admissions with the highest percentages in Trauma ICU (17%). Out of 159 patients with primary bloodstream infection, 61 patients died representing a crude mortality rate of 38%. Analysis of the organisms causing BSI showed that Gram positive organisms were reported in 69.1% (n = 121); MRSA was the most prevalent (18.9%), followed by methicillin resistant coagulase negative Staphylococci (16%). Gram negative bacilli were reported in 29.1% (n = 51). In this case, <it>Klebsiella pneumoniae </it>was the most common (10.3%) followed <it>E coli </it>(8.6%). <it>Candida spp</it>. was reported only in (1.7%) of isolates. Antibiotics sensitivities of Gram positive organisms showed that these organisms were mostly sensitive to vancomycin (90.1%), while Gram negative organisms were mostly sensitive to imipenem (90.2%). In this study we tested Gram negative isolates for the production of the ESBL enzyme and concluded that 64.7% (33/51) of patients' isolates and 20/135 (14.8%) environmental isolates were confirmed to be ESBL producers. The type of β-lactamase gene was determined by polymerase chain reaction which showed that SHV was the main type. Molecular typing was done for 18 Klebsiella pneumoniae strains that caused nosocomial BSI and for the 36 Klebsiella pneumoniae strains which were isolated from the environmental samples by the RAPD method. The two environmental strains were identical, with one isolated from a patient, which confirms the serious role of the hospital environment in the spread of infections.</p> <p>Conclusion</p> <p>Nosocomial BSI represents a current problem in Assiut University Hospitals, Egypt. Problems associated with BSI include infection with multidrug resistant pathogens (especially ESBLs) which are difficult to treat and are associated with increased mortality. Of all available anti-microbial agents, carbapenems are the most active and reliable treatment options for infections caused by ESBL isolates. However, overuse of carbapenems may lead to resistance of other Gram-negative organisms.</p

Mitigation of acetaminophen-induced liver toxicity by the novel phosphatidylinositol 3-kinase inhibitor alpelisib

The sterile inflammatory response mediated by Toll-like receptors (TLRs) 4 and 9 is implicated in the massive hepatic damage caused by acetaminophen (APAP)-overdose. There is a crosstalk between TLR-dependent signaling with other intracellular kinases like phosphatidylinositol 3-kinases (PI3Ks). Nevertheless, the detailed role of PI3Kα is still unknown in hepatic sterile inflammation. Accordingly, the effect of the novel PI3Kα inhibitor alpelisib was investigated in the setting of APAP-driven sterile inflammation in the liver. This was examined by pretreating mice with alpelisib (5 and 10 mg/kg, oral) 2 h before APAP (500 mg/kg, i.p.)-intoxication. The results indicated that alpelisib dose-dependently lowered APAP-induced escalation in serum liver function biomarkers and hepatic necroinflammation score. Alpelisib also attenuated APAP-induced rise in cleaved caspase 3 and proliferating cell nuclear antigen (PCNA) in the liver hepatocytes, as indices for apoptosis and proliferation. Mechanistically, inhibition of PI3Kα by alpelisib limited APAP-induced overproduction of the pro-inflammatory tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in the blood circulation via switching off the activation of several signal transduction proteins, including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), signal transducer and activator of transcription-3 (Stat-3), glycogen Synthase Kinase (GSK)-3β and nuclear factor (NF)-κB. Alpelisib also impaired APAP-instigated immune cell infiltration in the liver via reducing systemic granulocyte/macrophage-colony stimulating factor (GM-CSF) release and reversed APAP-induced abnormalities in the systemic and hepatic levels of the anti-inflammatory IL-10 and IL-22. In conclusion, selective modulation of the PI3Kα activity by alpelisib can hinder the inflammatory response and infiltration of immune cells occurring by APAP-hepatotoxicity