A reconfigurable wideband and multiband antenna using dual-patch elements for compact wireless devices

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 IEEEA reconfigurable wideband and multiband C-Slot patch antenna with dual-patch elements is proposed and studied. It occupies a compact volume of 50 × 50 × 1.57 (3925 mm3), including the ground plane. The antenna can operate in two dual-band modes and a wideband mode from 5 to 7 GHz. Two parallel C-Slots on the patch elements are employed to perturb the surface current paths for excitation of the dual-band and the wideband modes. Two switches, implemented using PIN diodes, are placed on the connecting lines of a simple feed network to the patch elements. Dual-band modes are achieved by switching “ON” either one of the two patch elements, while the wideband mode with an impedance bandwidth of 33.52% is obtained by switching “ON” both patch elements. The frequencies in the dual-band modes can be independently controlled using positions and dimensions of the C-Slots without affecting the wideband mode. The advantage of the proposed antenna is that two dual-band operations and one wideband operation can be achieved using the same dimensions. This overcomes the need for increasing the surface area normally incurred when designing wideband patch antennas. Simulation results are validated experimentally through prototypes. The measured radiation patterns and peak gains show stable responses and are in good agreements. Coupling between the two patch elements plays a major role for achieving the wide bandwidth and the effects of mutual coupling between the patch elements are also studied

Core-scale characterisation of flow in tight Arabian formations

Peer reviewedPublisher PD

Degradation of human kininogens with the release of kinin peptides by extracellular proteinases of Candida spp.

The secretion of proteolytic enzymes by pathogenic microorganisms is one of the most successful strategies used by pathogens to colonize and infect the host organism. The extracellular microbial proteinases can seriously deregulate the homeostatic proteolytic cascades of the host, including the kinin-forming system, repeatedly reported to he activated during bacterial infection. The current study assigns a kinin-releasing activity to secreted proteinases of Candida spp. yeasts, the major fungal pathogens of humans. Of several Candida species studied, C. parapsilosis and C. albicans in their invasive filamentous forms are shown to produce proteinases which most effectively degrade proteinaceous kinin precursors, the kininogens. These enzymes, classified as aspartyl proteinases, have the highest kininogen-degrading activity at low pH (approx. 3.5), but the associated production of bradykinin-related peptides from a small fraction of kininogen molecules is optimal at neutral pH (6.5). The peptides effectively interact with cellular B2-type kinin receptors. Moreover, kinin-related peptides capable of interacting with inflammation-induced B1-type receptors are also formed, but with a reversed pH dependence. The presented variability of the potential extracellular kinin production by secreted aspartyl proteinases of Candida spp. is consistent with the known adaptability of these opportunistic pathogens to different niches in the host organism

Influence of Using High Volume Fraction of Silica Fume on Mechanical and Durability Properties of Cement Mortar

The high pollution caused by CO2 emission and the high level of energy consumed during cement manufacturing led the researchers to look for alternative techniques to reduce these environmental effects. One of these techniques includes reducing the content of cement in the mix by replacing it with supplementary cementitious materials such as fly ash, slag, silica fume, and so on. Many previous studies dealt with the utilizing of the high volume of supplementary cementitious materials, such as fly ash and slag. However, limited studies investigated the impact of silica fume on mortar or concrete properties in percentages of more than 30%. Thus, to produce environmentally friendly concrete, this study was performed to investigate the effect of the high replacement level of cement with silica fume on the properties of cement mortar. Six replacement proportions of silica fume (0%, 30%, 40%, 50%, 60% and 70%) were used in this paper. This paper used the flow rate, compressive strength, water absorption, bulk density and volume of permeable voids tests to test the effect of silica fume on different mortar characteristics. The results indicated that the best mixture among all other mixes was found by 50% substitution of silica fume. At this percentage, an enhancement in compressive strength of nearly 83%, 74% and 75% at 7, 28 and 56 days, respectively and an improvement in water absorption resistance by 8% compared to the control mixture were achieved

Positive effects of a novel non-peptidyl low molecular weight radical scavenger in renal ischemia/reperfusion: a preliminary report

Ischemia/reperfusion (I/R) is one of the most common causes of acute kidney injury. Reactive oxygen species have been recognized to be an important contributor to the pathogenesis of I/R injury. We hypothesize that a non-peptidyl low molecular weight radical scavenger (IAC) therapy may counteract this factor, ultimately providing some protection after acute phase renal I/R injury. The aim of this preliminary study was to assess the ability of IAC to reduce acute kidney injury in C57BL/6 mice after 30-minute of bilateral ischemia followed by reperfusion. The rise in serum creatinine level was higher in C57BL/6 control mice after I/R when compared to IAC (1 mg)-treated mice. Control mice showed greater body weight loss compared to IAC-treated mice, and at pathology, reduced signs of tubular necrosis were also evident in IAC-treated mice. These preliminary evidences lay the basis for more comprehensive studies on the positive effects of IAC as a complementary therapeutic approach for acute phase renal I/R injury

Genomic profiling of malignant peritoneal mesothelioma reveals recurrent alterations in epigenetic regulatory genes BAP1, SETD2, and DDX3X.

Malignant mesothelioma is a rare cancer that arises from the mesothelial cells that line the pleural cavity and less commonly from the peritoneal lining of the abdomen and pelvis. Most pleural mesotheliomas arise in patients with a history of asbestos exposure, whereas the association of peritoneal mesotheliomas with exposure to asbestos and other potential carcinogens is less clear, suggesting that the genetic alterations that drive malignant peritoneal mesothelioma may be unique from those in pleural mesothelioma. Treatment options for all malignant mesotheliomas are currently limited, with no known targeted therapies available. To better understand the molecular pathogenesis of malignant peritoneal mesothelioma, we sequenced 510 cancer-related genes in 13 patients with malignant mesothelioma arising in the peritoneal cavity. The most frequent genetic alteration was biallelic inactivation of the BAP1 gene, which occurred in 9/13 cases, with an additional two cases demonstrating monoallelic loss of BAP1. All 11 of these cases demonstrated loss of BAP1 nuclear staining by immunohistochemistry, whereas two tumors without BAP1 alteration and all 42 cases of histologic mimics in peritoneum (8 multilocular peritoneal inclusion cyst, 6 well-differentiated papillary mesothelioma of the peritoneum, 16 adenomatoid tumor, and 12 low-grade serous carcinoma of the ovary) demonstrated intact BAP1 nuclear staining. Additional recurrently mutated genes in this cohort of malignant peritoneal mesotheliomas included NF2 (3/13), SETD2 (2/13), and DDX3X (2/13). While these genes are known to be recurrently mutated in pleural mesotheliomas, the frequencies are distinct in peritoneal mesotheliomas, with nearly 85% of peritoneal tumors harboring BAP1 alterations versus only 20-30% of pleural tumors. Together, these findings demonstrate the importance of epigenetic modifiers including BAP1, SETD2, and DDX3X in mesothelial tumorigenesis and suggest opportunities for targeted therapies

Type of High Secondary School (Governmental Vs Private) and Type of High Secondary School Certificate (Sudanese Vs Arabian): Do They Affect Learning Style?

Background: People differ in the way they perceive, process, store, and recall what they are attempting to learn. This study aimed to assess the learning styles among preclinical 1st year medical students and the influence of the type of high secondary school (governmental vs. private) and type of high secondary school certificate (Sudanese vs. Arabian) on learning style.Materials and Methods: A cross sectional institutional-based study was conducted at Al Neelain University, Khartoum State, Sudan. First year students of Medicine, Dentistry and Physiotherapy Faculties were enrolled. The VARK (Visual, Auditory, Read and write, and Kinesthetic) learning style hard copy questionnaire, © Copyright Version 7.8 (2014) held by VARK Learn Limited, Christchurch, New Zealand was administered following permission. Data were analyzed using Statistical Package for Social Sciences (SPSS) version 21.Results: Out of 320 students, 198 correctly completed VARK questionnaires, with mean age of 17.88 years (SD 1.52) and 74.2% were female students. About 59.6% were from governmental schools and 79.4% of the studied students had Sudanese High Secondary Certificates. About 64.1% demonstrated singular mode preference. Inferential statistics showed statistically significant difference between the learning styles and the type of secondary school whether governmental or private (P-value 0.005) while no statistically significant difference in relation to the type of high school certificate of the studied group (P-value 0.225).Conclusion: The type of secondary school whether governmental or private may affect learning style of medical students while student's gender, type of college, or type of high school certificate (whether Sudanese or Arabian) do not. More andlarger studies are encouraged.Key word: Learning modalities, VARK questionnaire, Unimodal preference, Medicaleducation, Sudan