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Jorge Chávez,Omar Jiménez Alemán,Martín Flores Martínez,Héctor J. Vergara‑Hernández,Luis Olmos,Pedro Garnica‑González,Didier Bouvard 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.2
The design and fabrication of a bilayer Ti6Al4V–Ti6Al4V/30Ta component were performed by using the powder metallurgyprocess and solid-state sintering as the consolidation step. Phase change and sintering densifcation of the component werestudied by dilatometry. The addition of 30 vol% of Ta to the Ti6Al4V matrix had a noticeable efect over the microstructuraland mechanical properties of the alloy, which showed decrements of up to 12.2 and 21.5% in nano-hardness and elastic modulus, respectively. The decrement of these properties strongly afected the wear and corrosion performance of the component. Special attention was focused on the intermediate zone between layers denoted by a transition zone, which presented betterwear response because of the properties and microstructure caused by the gradient difusion of Ta. Ti6Al4V/30Ta alloyshowed an improved corrosion behaviour compared to Ti6Al4V alloy, decreasing 2.4 times their susceptibility to corrosionand about two orders of magnitude their corrosion rate. The bilayer component in this study is proposed as an alternative todecrease the consumption of expensive materials with improved properties.
Mallyolo Eliezer Pelayo-Salazar,Héctor Alfredo Montenegro-Rosales,Jorge Luis Balderrama-Bañares,Pablo Martínez-Arellano,Omar Andrés Campos-Flota,Laura Mestre-Orozco,Julio César López-Valdés 대한뇌혈관외과학회 2023 Journal of Cerebrovascular and Endovascular Neuros Vol.25 No.1
Objective: Arteriovenous malformations (AVMs) are benign congenital lesions. The estimated prevalence is 10-18 per 100,000 individuals, with an incidence rate of 1.1-1.4 per 100,000 person-year; only 12% of AVMs present symptoms during life. It is important to study different characteristics associated with AVMs because these patients require multidisciplinary treatment. Methods: A descriptive, observational, longitudinal, and retrospective study was carried out from January 15, 2016 to October 19, 2021. Convenience sampling was used on patients diagnosed with arteriovenous malformation. Sociodemographic data was obtained, such as: sex, age, site, predominant symptoms, clinical debut, type of malformation, data associated with post therapy evolution, type of embolizing agent used, associated complications, Rankin scale, and death. Results: Data from 535 procedures was collected, we calculated an incidence of 4.4 cases per million inhabitants. Ninety procedures in 56 patients that used endovascular therapy were obtained with a female-male ratio of 0.75 and an age distribution of 35±14 (SD). A 36.3±11.5 (SD) mm diameter was registered. There was a 33% success rate for endovascular surgery. Conclusions: The multidisciplinary treatment of AVMs is made up of three pillar techniques: microsurgical resection, embolization, and radio-neurosurgery. It is extremely important to make an appropriate decision, with an emphasis on achieving better functional outcomes for the patient. Although neurological endovascular therapy was initially used as an adjuvant treatment for neurosurgery and radio-neurosurgery, it has been used more and more frequently as the first line of treatment.
Omar H. Al-Obaidi 한국분석과학회 2023 분석과학 Vol.36 No.2
The synthesis of the Mannich base as a ligand (L) N-(morpholino (phenyl) methyl) acetamide is the subject of this study. Elemental analyses, FT-IR spectra, UV-vis, 1H-NMR, and magnetic measurements were used to confirm the synthesis of the [Ni(L)2]Cl2 complex, thermal analysis (TG/DTG), atomic absorption, and scanning, and structurally explained as electron microscopy (SEM), and X-ray powder diffraction (XRD) methods. The melting point of the complex and its molar conductivity were also measured. The suggested geometries of the complexes formed have a tetrahedral structure, according to the data acquired using various techniques. Theoretical approaches to the complex formation have been investigated. For molecular mechanics and semi-empirical calculations, the HYPERCHEM6 program had been used. The effect of the novel Ni(II) complex on the cancer cell Hepa-2 (human hepatocellular ademocarcinoma), that is the human laryngeal cancer, was studied. It has been found that these ligand and complex have potent effects on the cancer cell. The antibacterial activity of the free ligand and its complex was evaluated against two kinds of human pathogenic bacteria. The first category is Gram-positive (Staphylococcus aureas, epiderimids), whereas the second group is Gram-negative (Psedamonas aeruginosa, Escherichia coli) (from the diffusion method). Finally, it was discovered that various chemicals had varied growth-inhibiting effects on bacteria.
Omar H. Almahmoud,Lubna Abushaikha 한국아동간호학회 2023 Child Health Nursing Research Vol.29 No.2
Purpose: Developmental disabilities (DDs) are a global childhood problem whose prevalence is rising, with a disproportionate impact on individuals in low-and middle-income countries. However, data on the prevalence of DDs in the Arab world are limited. This review highlights what is currently known about the prevalence and risk factors of DDs in preschool children in the Arab world. Methods: PubMed, Cochrane Library, Scopus, CINAHL, Science Direct, and Google Scholar were searched for publications on DDs among preschool children in the Arab world. Only 14 studies were identified in the literature, from 12 Arab countries. Results: The overall estimated prevalence of DDs among preschool children in the Arab world is 27.5%. An analysis of risk factors for DDs showed that child-related, maternal, and family-related factors account for a significant cumulative risk of developing DDs in preschool children. Maternal factors, such as antenatal and perinatal complications, were the most common risk factors. Conclusion: The prevalence of DDs among preschoolers is significantly high in the Arab world, which emphasizes the importance of the early detection and diagnosis of DD, as well as its associated risk factors.
Omar, S A,Elsheery, N I,Kalaji, H M,Ebrahim, M K H,Pietkiewicz, S,Lee, C-H,Allakhverdiev, S I,Xu, Zeng-Fu Consultants Bureau [etc.] 2013 Biochemistry Vol.78 No.5
<P>Plant dehydrin proteins (DHNs) are known to be important for environmental stress tolerance and are involved in various developmental processes. Two full-length cDNAs JcDHN-1 and JcDHN-2 encoding two dehydrins from Jatropha curcas seeds were identified and characterized. JcDHN-1 is 764 bp long and contains an open reading frame of 528 bp. The deduced JcDHN-1 protein has 175 a.a. residues that form a 19.3-kDa polypeptide with a predicted isoelectric point (pI) of 6.41. JcDHN-2 is 855 bp long and contains an open reading frame of 441 bp. The deduced JcDHN-2 protein has 156 a.a. residues that form a 17.1-kDa polypeptide with a predicted pI of 7.09. JcDHN-1 is classified as type Y3SK2 and JcDHN-2 is classified as type Y2SK2 according to the YSK shorthand for structural classification of dehydrins. Homology analysis indicates that both JcDHN-1 and JcDHN-2 share identity with DHNs of other plants. Analysis of the conserved domain revealed that JcDHN-2 has glycoside hydrolase GH20 super-family activity. Quantitative real time PCR analysis for JcDHN-1 and JcDHN-2 expression during seed development showed increasing gene expression of both their transcript levels along with the natural dehydration process during seed development. A sharp increase in JcDHN-2 transcript level occurred in response to water content dropping from 42% in mature seeds to 12% in dry seeds. These results indicate that both JcDHNs have the potential to play a role in cell protection during dehydration occurring naturally during jatropha orthodox seed development.</P>
Sampling theorems associated with differential operators with finite rank perturbations
Mahmoud H. Annaby,Omar H. El-Haddad,Hassan A. Hassan 대한수학회 2016 대한수학회지 Vol.53 No.5
We derive a sampling theorem associated with first order self-adjoint eigenvalue problem with a finite rank perturbation. The class of the sampled integral transforms is of finite Fourier type where the kernel has an additional perturbation.
SAMPLING THEOREMS ASSOCIATED WITH DIFFERENTIAL OPERATORS WITH FINITE RANK PERTURBATIONS
Annaby, Mahmoud H.,El-Haddad, Omar H.,Hassan, Hassan A. Korean Mathematical Society 2016 대한수학회지 Vol.53 No.5
We derive a sampling theorem associated with first order self-adjoint eigenvalue problem with a finite rank perturbation. The class of the sampled integral transforms is of finite Fourier type where the kernel has an additional perturbation.
( El Enshasy H. ),( Y. Abdel Fattah ),( A. Atta ),( H. Omar ),( S. Abou El Magd ),( R. Abou Zahra ),( M. Anwar ) 한국미생물 · 생명공학회 2008 Journal of microbiology and biotechnology Vol.18 No.1
The kinetics of cell growth and Cyclosporin A (Cyc A) production by Tolypocladium inflatum were studied in shake flasks and bioreactors under controlled and uncontrolled pH conditions. In the case of the shake flask, the production time was extended to 226 h and the maximal antibiotic concentration was 76 mg/l. When scaling up the cultivation process to a bioreactor level, the production time was reduced to only 70 h with a significant increase in both the cell growth and the antibiotic production. The maximal dry cell weights in the case of the controlled pH and uncontrolled pH cultures in the bioreactor were 22.4 g/l and 14.2 g/l, respectively. The corresponding maximal dry cell weight values did not exceed 7.25 g/l with the shake flask cultures. The maximal values for Cyc A production were 144.72 and 131.4 mg/l for the controlled and uncontrolled pH cultures, respectively. It is also worth noting that a significant reduction was observed in both the dry cell mass and the antibiotic concentration after the Cyc A production phase, whereas the highest rate of antibiotic degradation was observed in the stirred tank bioreactor with an uncontrolled pH. Morphological characterization of the micromorphological cell growth (mycelial/pellet forms) was also performed during cultivation in the bioreactor.
Optimal WAMS Configuration in Nordic Power System
Mohamed A.M. Hassan,Omar H. Abdalla,Hady H. Fayek,Aisha H.A. Hashim,Siti Fauziah Toha International Journal of Computer ScienceNetwork S 2023 International journal of computer science and netw Vol.23 No.3
The Smart grids are considered as multi-disciplinary power systems where the communication networks are highly employed. This paper presents optimal wide area measurement system (WAMS) configuration in Nordic power system. The transition from SCADA to WAMS becomes now trend in all power systems to ensure higher reliability and data visibility. The optimization applied in this research considered the geographical regions of the Nordic power system. The research considered all the devices of WAMS namely phasor measurement units (PMUs), phasor data concentrators (PDCs) and communication links. The study also presents two scenarios for optimal WAMS namely base case and N-1 contingency as different operating conditions. The result of this research presents technical and financial results for WAMS configuration in a real power system. The optimization results are performed using MATLAB 2017a software application.