473 research outputs found
Double-diffusive natural convection with Soret/Dufour effects and energy optimization of Nano-Encapsulated Phase Change Material in a novel form of a wavy-walled I-shaped domain
Background: As building segment grows in parallel with amplifying population, the necessity for consumption of energy needed to passive and active heating or cooling buildings for thermal comfort increases. Schemes such as developing green buildings for sustainable architecture were utilized to address this issue. The utilization of Phase Change Materials (PCMs) with the aim of active and passive cooling or heating of buildings illustrates a promising and modern technique. Methods: This study's objective is to perform a numerical analysis using the finite element method, FEM for modeling free convection produced by double-diffusion (DDNC) with Soret/Dufour effects of Nano-Encapsulated PCMs within an I-shaped enclosure equipped with a novel type of corrugated vertical walls subjected to Neumann thermal and solutal conditions. Findings: Results are interpreted and assessed in relation to the governing factors, such as buoyancy ratio (N), Rayleigh and Lewis numbers (Ra, Le), the height of corrugated walls (a), Stefan number (Ste), non-dimensional fusion temperature (Ξf), Dufour (Df), and Soret (Sr) parameters. High values of N and Ra, and low values of Le and a, caused in the highest rate of heat and mass exchange. The irreversibilities due to the heat and mass transfer effects increase as the flow intensity within the system decrease. Decreasing the latent heat of the NEPCM cores and increasing their fusion temperature lowering the heat transfer rates, while improving mass transfer rates. This configuration can help in the design of the storage tank in hydronic apparatus for cooling, heating, and domestic hot water in buildings
Synthesis, structural and morphological characterizations of nano-Ru-based perovskites/RGO composites
Highly-dispersed Ru-based perovskites supported on reduced graphene oxide (A-RG) nanocomposites are prepared using different A-metal salts (Sr(NOâ)â, Ba(NOâ)â and Ca(NOâ)â). The procedure is based on a redox reaction between the metal precursors and graphene oxide (GO) using two different routes of reaction initiation: through thermal heating or by microwave-assisted heating. The resulting nanocomposites do not require further calcination, making this method less energy-demanding. In addition, no additional chemical reagents are required for either the GO reduction or the metal precursor oxidation, leading to an overall simple and direct synthesis method. The structure and morphology of the as-prepared A-RG (non-calcined) nanocomposites are characterized using various structural analyses including XRD, XPS, SEM/EDX and HR-TEM. Changing metal A in the perovskite as well as the âactivation methodâ resulted in significant structural and morphological changes of the formed composites. SrRuOâ and BaRuOâ in combination with RuOâ are obtained using a conventional combustion method, while SrRuOâ (~1 nm size) in combination with Ru nanoparticles are successfully prepared using microwave irradiation. For the first time, a microwave-assisted synthesis method (without calcination) was used to form crystalline nano-CaRuOâ
Consideration of NDVI thematic changes in density analysis and floristic composition of Wadi Yalamlam, Saudi Arabia
Wadi Yalamlam is
known as one of the significant wadis in the west of Saudi Arabia. It is a
very important water source for the western region of the country. Thus, it
supplies the holy places in Mecca and the surrounding areas with drinking
water. The floristic composition of Wadi Yalamlam has not been
comprehensively studied. For that reason, this work aimed to assess the wadi
vegetation cover, life-form presence, chorotype, diversity, and community
structure using temporal remote sensing data. Temporal datasets spanning
4Â years were acquired from the Landsat 8 sensor in 2013 as an early
acquisition and in 2017 as a late acquisition to estimate normalized
difference vegetation index (NDVI) changes. The wadi was divided into seven
stands. Stands 7, 1, and 3 were the richest with the highest Shannon index
values of 2.98, 2.69, and 2.64, respectively. On the other hand, stand 6 has
the least plant biodiversity with a Shannon index of 1.8. The study also
revealed the presence of 48 different plant species belonging to 24 families.
Fabaceae (17 %) and Poaceae (13 %) were the main families that form
most of the vegetation in the study area, while many families were
represented by only 2 % of the vegetation of the wadi. NDVI analysis
showed that the wadi suffers from various types of degradation of the
vegetation cover along with the wadi main stream.</p
Geostationary Operational Environmental Satellite (GOES)-8 mission flight experience
The Geostationary Operational Environmental Satellite (GOES)-8 spacecraft was launched on April 13, 1994, at 06:04:02 coordinated universal time (UTC), with separation from the Atlas-Centaur launch vehicle occurring at 06:33:05 UTC. The launch was followed by a series of complex, intense operations to maneuver the spacecraft into its geosynchronous mission orbit. The Flight Dynamics Facility (FDF) of the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) was responsible for GOES-8 attitude, orbit maneuver, orbit determination, and station acquisition support during the ascent phase. This paper summarizes the efforts of the FDF support teams and highlights some of the unique challenges the launch team faced during critical GOES-8 mission support. FDF operations experience discussed includes: (1) The abort of apogee maneuver firing-1 (AMF-1), cancellation of AMF-3, and the subsequent replans of the maneuver profile; (2) The unexpectedly large temperature dependence of the digital integrating rate assembly (DIRA) and its effect on GOES-8 attitude targeting in support of perigee raising maneuvers; (3) The significant effect of attitude control thrusting on GOES-8 orbit determination solutions; (4) Adjustment of the trim tab to minimize torque due to solar radiation pressure; and (5) Postlaunch analysis performed to estimate the GOES-8 separation attitude. The paper also discusses some key FDF GOES-8 lessons learned to be considered for the GOES-J launch which is currently scheduled for May 19, 1995
The role of diet and lifestyle in women with breast cancer: An update review of related research in the Middle East
© Zainab Taha and Sakina E. Eltom 2018. Breast cancer is the most common malignancy among Arab women in Eastern Mediterranean Region (EMR). The incidence of breast cancer has substantially increased in recent years among this women population, especially those younger than 50, and the incidence is expected to double by 2030. Considerable experimental evidence supports the potential role of dietary habits and lifestyle in cancer etiology and cancer prevention. In this review we examined the literature for evidence to link dietary choices and the rise in incidence and mortality of breast cancer among women in EMR. A literature search was conducted in PubMed and Ovid MEDLINE databases up to December 2017. The search terms used are breast cancer prevalence, breast cancer incidence worldwide, breast cancer and: nutrition, protein intake, Vitamin D intake, fat intake, phytoestrogens, EMR, Arab, Middle East, Gulf countries, the UAE Arab women, breast cancer risk, diet, and chemoprevention. We found evidence to suggest that there is an alarming epidemic of obesity among women in most of the EMR countries, especially Gulf Cooperation Council (GCC) countries. The rise in the new breast cancer cases among women could be attributed to excess body weight. Their dietary pattern, which correlates with obesity, can be an important factor in the etiology of cancer. Although very few studies were found to support a direct causal relationship between obesity and breast cancer in the EMR, circumstantial evidence clearly points to the possible role of the epidemic, obesity, in this population and the startling rise in cases of breast cancer. Well-designed and systematic studies are urgently needed to confirm these associations and to elucidate potential mechanisms. More urgently, calls to action are needed in many sectors and at all levels of society, to establish intensive strategies for reducing obesity and promoting an overall healthy diet. Continued and expanded research on diet, lifestyle, and breast cancer risk is urgently needed to build the foundation for future progress in evidence-based public health efforts
Protein Energy Wasting in a Sample of Egyptian Children on Regular Hemodialysis: Relation to Anorexigenic Hormones
BACKGROUND: Increased incidence of pediatric end-stage renal disease (ESRD) with associated serious consequences indicating a major public health problem. Malnutrition and uremic wasting are leading causes of growth impairment and increasing morbidity and mortality of pediatric ESRD patients, predominantly those on regular hemodialysis (HD). Ghrelin and obestatin, which are known appetite regulatory hormones, might have a pivotal role in uremic wasting and growth impairment in hemodialyzed children.
AIM: The aim of the present study was to measure serum unacylated ghrelin (UAG) and obestatin and to investigate their roles in the growth impairment of Egyptian hemodialyzed children.
SUBJECTS AND METHODS: The study included 50 hemodialyzed and 40 healthy children recruited from the Department of Nephrology, Pediatric Hospital, Ain Shams University. Full clinical examination and measurement of anthropometric indices were done. Routine labs were done as well, with an assessment of serum levels of obestatin, UAG, and insulin by enzyme linked immunosorbent assay. Furthermore, we determined fasting serum glucose and lipid profile with the calculation of homeostasis model assessment for insulin resistance (HOMA-IR).
RESULTS: Anthropometric measurements were statistically significantly decreased in the hemodialyzed group than that of the control group (p < 0.05). Weight z-score was the most affected anthropometric parameter (37 patients = 74% with underweight and 13 patients = 26% with normal weight). The hemodialyzed children showed a significant increase of UAG, obestatin, insulin, glucose, HOMA-IR, and TG, while a significant decrease of HDL-cholesterol and albumin (p < 0.01). UAG had a negative correlation with Wt-z score, Ht z-score, fat mass %, albumin, and TG while obestatin was inversely correlated to Wt-z score, BMI z-score, waist circumference, and waist-height ratio (W/H).
CONCLUSION: UAG and obestatin hormones were elevated in a group of Egyptian children on regular HD. These hormones were strongly related to the impairment of renal functions, and anthropometric parameters, dyslipidemia, hypoalbuminemia, and insulin resistance in these pediatric hemodialyzed patients
Egyptian consensus on treat-to-target approach for osteoporosis: a clinical practice guideline from the Egyptian Academy of bone health and metabolic bone diseases
Background: This study was carried out to achieve an Egyptian expert consensus on a treat-to-target managementstrategy for osteoporosis using Delphi technique. A scientific committee identified researchers and clinicians with expertise in osteoporosis in Egypt. Delphi process was implemented (2 rounds) to establish a consensus on 15
clinical standards: (1) concept, (2) diagnosis, (3) case identification, (4) whom to treat, (5) who should treat?, (6) case stratification and intervention thresholds, (7) falls risk, (8) investigations, (9) treatment target, (10) management, (11) optimum treatment duration, (12) monitoring, (13) drug holiday, (14) osteoporosis in men, and (15) post-fracture care and fracture liaison service.
Results: The surveys were sent to an expert panel (n = 25), of whom 24 participated in the two rounds. Respondents were drawn from different governorates and health centres across Egypt including the Ministry of Health. Most of the participants were rheumatologists (76%), followed by internists (8%), orthopaedic doctors (4%), rehabilitation doctors (4%), primary care (4%), and ortho-geriatrics (4%) physicians. Seventy-two recommendations, categorised into 15 sections, were obtained. Agreement with the recommendations (rank 7â9) ranged from 83.4 to 100%. Consensus was reached (i.e. â„ 75% of respondents strongly agreed or agreed) on the wording of all 15 clinical standards identified by the scientific committee. An algorithm for the management of postmenopausal osteoporosis has been suggested.
Conclusion: A wide and representative panel of experts established a consensus regarding the management of
osteoporosis in Egypt. The developed guidelines provide a comprehensive approach to the assessment and management of osteoporosis for all Egyptian healthcare professionals who are involved in its management
Pre-mRNA splicing repression triggers abiotic stress signaling in plants
[EN] Alternative splicing (AS) of precursor RNAs enhances transcriptome plasticity and proteome diversity in response to diverse growth and stress cues. Recent work has shown that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various inhibitors of AS. Here, we show that the macrolide pladienolide B (PB) inhibits constitutive splicing and AS in plants. Also, our RNA sequencing (RNA-seq) data revealed that PB mimics abiotic stress signals including salt, drought and abscisic acid (ABA). PB activates the abiotic stress-and ABA-responsive reporters RD29A::LUC and MAPKKK18::uidA in Arabidopsis thaliana and mimics the effects of ABA on stomatal aperture. Genome-wide analysis of AS by RNA-seq revealed that PB perturbs the splicing machinery and leads to a striking increase in intron retention and a reduction in other forms of AS. Interestingly, PB treatment activates the ABA signaling pathway by inhibiting the splicing of clade A PP2C phosphatases while still maintaining to some extent the splicing of ABA-activated SnRK2 kinases. Taken together, our data establish PB as an inhibitor and modulator of splicing and a mimic of abiotic stress signals in plants. Thus, PB reveals the molecular underpinnings of the interplay between stress responses, ABA signaling and post-transcriptional regulation in plants.We wish to thank members of the Laboratory for Genome Engineering at King Abdullah University of Science and Technology for helpful discussions and comments on the manuscript. We wish to thank Moussa Benhamed for helpful discussions and suggestions and for providing key materials. We wish to thank Sean Cutler for providing Arabidopsis seeds of MAKPKKK18-uidA. This study was supported by King Abdullah University of Science and Technology. Work in PR's laboratory was funded by grant BIO2014-52537-R from MINECO. Work in PD's laboratory is funded by grant PTDC/BIA-PLA/1084/2014 from FCT. The authors declare no conflicts of interest.Ling, Y.; Alshareef, S.; Butt, H.; Lozano Juste, J.; Li, L.; Galal, AA.; Moustafa, A.... (2017). Pre-mRNA splicing repression triggers abiotic stress signaling in plants. The Plant Journal. 89(2):291-309. https://doi.org/10.1111/tpj.13383S29130989
Ethnicity, consanguinity, and genetic architecture of hypertrophic cardiomyopathy
AIMS: Hypertrophic cardiomyopathy (HCM) is characterized by phenotypic heterogeneity that is partly explained by the diversity of genetic variants contributing to disease. Accurate interpretation of these variants constitutes a major challenge for diagnosis and implementing precision medicine, especially in understudied populations. The aim is to define the genetic architecture of HCM in North African cohorts with high consanguinity using ancestry-matched cases and controls. METHODS AND RESULTS: Prospective Egyptian patients (n = 514) and controls (n = 400) underwent clinical phenotyping and genetic testing. Rare variants in 13 validated HCM genes were classified according to standard clinical guidelines and compared with a prospective HCM cohort of majority European ancestry (n = 684). A higher prevalence of homozygous variants was observed in Egyptian patients (4.1% vs. 0.1%, P = 2 Ă 10-7), with variants in the minor HCM genes MYL2, MYL3, and CSRP3 more likely to present in homozygosity than the major genes, suggesting these variants are less penetrant in heterozygosity. Biallelic variants in the recessive HCM gene TRIM63 were detected in 2.1% of patients (five-fold greater than European patients), highlighting the importance of recessive inheritance in consanguineous populations. Finally, rare variants in Egyptian HCM patients were less likely to be classified as (likely) pathogenic compared with Europeans (40.8% vs. 61.6%, P = 1.6 Ă 10-5) due to the underrepresentation of Middle Eastern populations in current reference resources. This proportion increased to 53.3% after incorporating methods that leverage new ancestry-matched controls presented here. CONCLUSION: Studying consanguineous populations reveals novel insights with relevance to genetic testing and our understanding of the genetic architecture of HCM
New variant with a previously unrecognized mechanism of pathogenicity in hypertrophic cardiomyopathy
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