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Materials Sciences and Applications 2014年第10期5卷 685-697页

作者： omar A. al-Hartomy Ahmed A. al-Ghamdi Said A. Farha al-Said Nikolay Dishovsky Michael B. Ward Petrunka Malinova Mihail Mihaylov Department of Physics Faculty of Science King Abdulaziz University Jeddah Saudi Arabia Department of Physics Faculty of Science King Abdulaziz University Jeddah Saudi Arabia Department of Physics Faculty of Science University of Tabuk Tabuk Saudi Arabia Department of Polymer Engineering University of Chemical Technology and Metallurgy Sofia Bulgaria LEMAS Institute for Materials Research SPEME University of Leeds Leeds UK

Different types of carbon-silica fillers were prepared via pyrolysis-cum-water vapor of waste green tires tread and impregnation method. Dual phase fillers have been characterized by energy dispersive X-ray (EDX) spectroscopy in a scanning transmission electron microscope (STEM) or STEM-EDX. Phase distribution in hybrid fillers for rubber was investigated. The results achieved show that the conditions of obtaining influence the distribution and the location of the phases in the carbon-silica hybrid fillers as well as their most essential characteristics including specific area, oil absorption number, iodine adsorption number, ash content and others.

关键词： Carbon Silica Hybrid Fillers Pyrolisis Impregnation Filler Characterization STEM-EDX Method

Temporal Stability Analysis of Magnetized Hybrid Nanofluid Propagating through an Unsteady Shrinking Sheet: Partial Slip Conditions

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Computers, Materials & Continua 2021年第2期66卷 1963-1975页

作者： Liaquat ali Lund Zurni omar Sumera Dero Yuming Chu Ilyas Khan Kottakkaran Sooppy Nisar School of Quantitative Sciences Universiti Utara Malaysia06010SintokKedahMalaysia KCAET Khairpur Mir’s Sindh Agriculture UniversityTandojam Sindh70060Pakistan IICT University of SindhJamshoro76080Pakistan Department of Mathematics Huzhou UniversityHuzhou313000China Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering Changsha University of Science&TechnologyChangsha410114China Faculty of Mathematics and Statistics Ton Duc Thang UniversityHo Chi Minh CityVietnam Department of Mathematics College of Arts and SciencesPrince Sattam bin Abdulaziz UniversityWadi AldawaserSaudi Arabia

The unsteady magnetohydrodynamic(MHD)flow on a horizontal preamble surface with hybrid nanoparticles in the presence of the first order velocity and thermal slip conditions are ***(al_(2)O_(3))and copper(Cu)are considered as hybrid nanoparticles that have been dispersed in water in order to make hybrid nanofluid(Cu-al_(2)O_(3)/water).The system of similarity equations is derived from the system of partial differential equations(PDEs)by using variables of similarity,and their solutions are gotten with shooting method in the Maple *** certain ranges of unsteadiness and magnetic parameters,the presence of dual solutions can be ***,it is examined that layer separation is deferred due to the effect of the hybrid ***,the capacity of the thermal enhancement of Cu-al_(2)O_(3)/water hybrid nanofluid is higher as compared to al_(2)O_(3)/water based nanofluid and enhancements inCu are caused to rise the fluid temperature in both *** the last,solutions stability analyzes were also carried out and the first solution was found to be stable.

关键词： Cu−al_(2)O_(3)/H2O hybrid nanofluid magnetic field slip conditions dual solutions

Comparative Study of the Antioxidant Activity of Two Popular Green Tea Beverages Available in the Local Market of Saudi Arabia

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Natural Science 2016年第6期8卷 227-234页

作者： Ulfat M. omar Ayat M. Shorbaji Entesar M. Arrait Tasneem D. al Agha Hala F. al-Marzouki Huda A. al Doghaither Ayat B. al-Ghafari Department of Biochemistry Faculty of Science King Abdulaziz University Jeddah KSA

Antioxidants have numerous applications due to their multiple roles in diminishing harmful effects of oxidative stress. The objective of this work was to highlight the importance of green tea by evaluating the antioxidant activity of the most popular green tea brands in Saudi Arabia, Lipton and Rabea. To our knowledge, no studies have so far been done to estimate the antioxidant activity of these brands. To determine the antioxidant activities of these two brands, 10 mg/ml of each brand was extracted and their total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, hydrogen peroxide scavenging activity, ferric reducing power and ferrous ion chelating effect were measured. The TPC of Lipton tea was 678.7 υg of gallic acid equivalents (GAE)/10mg, whereas in Rabea tea, the TPC was 647.1 υg GAE/10mg. The presence study indicated that there were no significant differences in total phenolic contents and the percentage inhibition as shown in DPPH and H2O2 assays among Lipton and Rabea green teas. Moreover, it was found that all assays have exhibited high antioxidant activity in both green teas. In conclusion, our study showed evidence for evenness and stability of the antioxidant activity of the two commercial green teas available in the markets of Saudi Arabia. Continued researches are needed to further the current knowledge on the health-promoting effects of this popular beverage using different supplements by different mechanisms.

关键词： Green Tea Polyphenols Antioxidants Radical Scavenging Activity Total Phenolic Content

Role of Ultrasound in Evaluation of Developmental Dysplasia of the Hip in Infants

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Open Journal of Pediatrics 2017年第1期7卷 1-12页

作者： ali Hassan A. ali Jamaan al-Zahrani Abbas Elbakry A. Elsayed omar O. Serhan Anatomy Department College of Medicine Prince Sattam Bin Abdulaziz University Al-Kharj KSA Anatomy Department Faculty of Medicine Al-Azhar University Cairo Egypt Department of Family Medicine College of Medicine Prince Sattam Bin Abdulaziz University Al-Kharj KSA Pediatric Department College of Medicine Prince Sattam Bin Abdulaziz University Al-Kharj KSA Pediatric Department Faculty of Medicine Al-Azhar University Assuit Egypt Radiology Department King Khalid Hospital Al-Kharj KSA

Background/Aim: The present study was directed to investigate the accuracy of ultrasound (USG) in early detection of developmental dysplasia of the hip (DDH) to prevent permanent complications. Material & Methods: A total of 276 infants was investigated;their ages range from 1 - 6 months. Patients referred from the clinic based on clinical assessment (mainly Barlo & Ortolani maneuvers). Then the patient’s hips were examined by expert radiologists in USG scan. After that, dynamic (coronal and transverse) & static ultrasound views evaluated by the same radiologist using Graf’s criteria. Infants with abnormal ultrasound findings suggestive of DDH were followed up after 4 - 6 weeks by the same investigator to monitor the progress. At the same time, the patient referred to a specialist for conservative management from the first positive findings. Results: Among the 276 referred patients, infants with normal stable hips (Graf Type I and Type II a+) were 221 (80%), 155 of them were female and 66 male infants. Infants with unstable hips based on Graf’s criteria (Type II a-, II b, II c and Type III a) were 55 (20%). Out of 55 with abnormal findings, the affected hips on both sides, right and left were: 5 cases (1.8%), 7 (2.5%) and 43 hips (15.5%) consecutively. Out of 55 infants affected;3 referred to tertiary centers for further surgical management while 52 managed conservatively. Conclusion: Delayed treatment rates of DDH and complications could be reduced by the usage of the USG after the first month of life. In addition to physical assessment, USG for high-risk infants will provide more accurate diagnosis and minimize complications.

关键词： Developmental Dysplasia of the Hip Ultrasonography Infants Graf’s Criteria

CRISPR-Cas12a-Empowered Electrochemical Biosensor for Rapid and Ultrasensitive Detection of SARS-CoV-2 Delta Variant

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Nano-Micro Letters 2022年第10期14卷 83-94页

作者： Chenshuo Wu Zhi Chen Chaozhou Li Yabin Hao Yuxuan Tang Yuxuan Yuan Luxiao Chai Taojian Fan Jiangtian Yu Xiaopeng Ma omar Aal-Hartomy SWageh Abdullah Gal-Sehemi Zhiguang Luo Yaqing He Jingfeng Li Zhongjian Xie Han Zhang International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of EducationInstitute of Microscale OptoelectronicsCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060People’s Republic of China Shenzhen International Institute for Biomedical Research Shenzhen 518116People’s Republic of China Department of Respiratory Shenzhen Children’s HospitalShenzhen 518038People’s Republic of China Institute of Pediatrics Shenzhen Children’s HospitalShenzhen 518038People’s Republic of China Shenzhen Han’s Tech Limited Company Shenzhen 518000People’s Republic of China Hospital of Guangzhou Medical University Qingyuan city People’s HospitalQingyuan 511518People’s Republic of China Department of Physics Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia Research Center for Advanced Materials Science(RCAMS) King Khalid UniversityP.O.Box 9004Abha 61413Saudi Arabia Department of Chemistry College of ScienceKing Khalid UniversityP.O.Box 9004Abha 61413Saudi Arabia Zhongmin(Shenzhen)Intelligent Ecology Co. LtdShenzhen 518055People’s Republic of China Shenzhen Center for Disease Control and Prevention Shenzhen 518055People’s Republic of China

Coronavirus disease 2019(COVID-19)is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The gold standard method for the diagnosis of SARS-CoV-2 depends on quantitative reverse transcription-polymerase chain reaction till now,which is time-consuming and requires expensive instrumentation,and the confirmation of variants relies on further sequencing ***,we first proposed a robust technique-methodology of electrochemical CRISPR sensing with the advantages of rapid,highly sensitivity and specificity for the detection of SARS-CoV-2 *** enhance the sensing capability,gold electrodes are uniformly decorated with electro-deposited gold *** DNA template identical to SARS-CoV-2 Delta spike gene sequence as model,our biosensor exhibits excellent analytical detection limit(50 fM)and high linearity(R2=0.987)over six orders of magnitude dynamic range from 100 fM to 10 nM without any nucleic-acid-amplification *** detection can be completed within 1 h with high stability and specificity which benefits from the CRISPR-Cas ***,based on the wireless micro-electrochemical platform,the proposed biosensor reveals promising application ability in point-of-care testing.

关键词： SARS-COV-2 variant Methodology of electrochemical CRISPR sensing(MOECS) Gold nanoparticles(AuNPs) Point-of-care testing(POCT)

Correlation between Electrical Conductivity and Microwave Shielding Effectiveness of Natural Rubber Based Composites, Containing Different Hybrid Fillers Obtained by Impregnation Technology

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Materials Sciences and Applications 2016年第9期7卷 496-509页

作者： Ahmed A. al-Ghamdi omar A. al-Hartomy Falleh R. al-Solamy Nikolay T. Dishovsky Petrunka Malinova Nikolay T. Atanasov Gabriela L. Atanasova Department of Physics Faculty of Science King Abdulaziz University Jeddah KSA Department of Mathematics Faculty of Science King Abdulaziz University Jeddah KSA Department of Polymer Engineering University of Chemical Technology and Metallurgy Sofia Bulgaria Department of Telecommunications Faculty of Telecommunications and Management University of Telecommunications and Post Sofia Bulgaria Department of Communication and Computer Engineering Faculty of Engineering South-West University ‘Neofit Rilski’ Blagoevgrad Bulgaria

The paper presents the synthesis and characterization of carbon black/silicone dioxide hybrid fillers obtained by an impregnation technology. The electromagnetic interference shielding effectiveness of the composites filled with carbon black/silicone dioxide hybrid fillers was measured in wide frequency range of 1 - 12 GHz. The dc and ac electrical conductivity of composites also have been investigated. The relationship between electrical (dc and ac) conductivity and shielding effectiveness was analyzed. A positive correlation was found between the absorptive shielding effectiveness and ac conductivity for composites comprising conductive carbon black/silica filler, when the filler loading is above the percolation threshold.

关键词： Composite Materials Correlation Electrical Conductivity Shielding Effectiveness

Phenolic Contents and Antioxidant Activities of Green Tea with and without Lemon

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Natural Science 2016年第6期8卷 247-255页

作者： Ayat B. al-Ghafari Ayat M. Shorbaji Lamya A. al-Sarori Eman O. Baduwailan Aisha A. Basaar Huda A. al Doghaither Hala F. al-Marzouki Ulfat M. omar Department of Biochemistry Faculty of Science King Abdulaziz University Jeddah KSA

Tea is the most widely consumed beverage throughout the world, after water and is considered as a good antioxidant nutrient against free radical reactions. Lemons are citrus fruits that are very common in many parts of the world and are well known for their health benefits. In this study, different assays were used to evaluate total phenolic content and antioxidant activities of green tea with and without lemon. Our results showed that green tea with lemon has higher phenolic content, stronger reducing power than green tea without lemon;and exhibits a significant inhibition of 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2). However, both samples exhibited high ferrous chelating activity with no significant difference among each other indicating a good antioxidant potential for both. This is a comparative study between green tea and green tea supplemented with lemon. The study contributes to a better understanding about how the addition of supplements like lemon might influence the antioxidant activity of tea.

关键词： Antioxidant Activity Green Tea Lemon Metal Chelation Phenolic Compounds Radical Scavenging Component

Innovative hydrophobic/hydrophilic perfluoropolyether(PFPE)/polyvinylidene fluoride(PVDF)composite membrane for vacuum membrane distillation

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Chinese Journal of Chemical Engineering 2022年第5期35卷 248-257页

作者： Jun Pan Xianli Xu Zhaohui Wang Shi-Peng Sun Zhaoliang Cui Lassaad Gzara Iqbal Ahmed omar Bamaga Mohammed albeirutty Enrico Drioli State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemistry and Chemical EngineeringNanjing Tech UniversityNanjing 210009China National Engineering Research Center for Special Separation Membrane Nanjing Tech UniversityNanjing 210009China Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM) Nanjing Tech UniversityNanjing 210009China Center of Excellence in Desalination Technology King Abdulaziz UniversityJeddah 21589Saudi Arabia Mechanical Engineering Department King Abdulaziz UniversityJeddah 21589Saudi Arabia Research Institute on Membrane Technology ITM-CNRVia Pietro Bucci 17/CRende 87036Italy

Though membrane distillation(MD)has gained more and more attention in the field of desalination,the wetting phenomenon was still a non-negligible *** this work,a method combined dip-coating and UV in situ polymerization for preparing hydrophobic/hydrophilic perfluoropolyether(PFPE)/polyvinylidene fluoride composite *** composite membrane consisted of a top thin hydrophobic coating layer and hydrophilic substrate *** terms of anti-wetting properties,contact angle and liquid entry pressure of all composite membranes(except for those based on 0.45μm)exceeded 160°and 0.3 MPa,*** particular,the desalination performance was tested in vacuum membrane distillation tests by feeding 3.5%(mass)saline solution(NaCl)at 60℃.The composite membranes with larger support pore size and lower PFPE content had higher membrane distillation *** for stability tests(testing the 0.22μm membrane coated by 5%(mass)PFPE),the highest MD flux29.08 kg·m^(-2)·h^(-1) and stable salt rejection(over 99.99%)during the *** that,the effects of coating material concentration and pore sizes of substrate membrane were also investigated for surface morphology and topography,porosity,mechanical strength and pore size *** work provided a simple and effective alternative to prepare excellent hydrophobic composite membranes for MD applications.

关键词： Desalination Membrane surface coating Composite membranes Anti-wetting Vacuum membrane distillation

MELex: The Construction of Malay-English Sentiment Lexicon

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Computers, Materials & Continua 2022年第4期71卷 1789-1805页

作者： Nurul Husna Mahadzir Mohd Faizal omar Mohd Nasrun Mohd Nawi Anas ASalameh Kasmaruddin Che Hussin Abid Sohail Faculty of Computer and Mathematical Sciences Universiti Teknologi MARA(UiTM)Kedah08400MerbokKedahMalaysia Department of Decision Sciences School of Quantitative SciencesUniversiti Utara Malaysia06010KedahMalaysia Disaster Management of Institute School of Technology Management and LogisticUniversiti Utara Malaysia06010KedahMalaysia Department of Management Information System College of Business AdministrationPrince Sattam Bin Abdulaziz University165Al-KharjSaudi Arabia Faculty of Entrepreneurship and Business Universiti Malaysia KelantanMalaysia Department of Computer Science COMSATS University IslamabadLahorePakistan

Currently,the sentiment analysis research in the Malaysian context lacks in terms of the availability of the sentiment ***,this issue is addressed in this paper in order to enhance the accuracy of sentiment *** this study,a new lexicon for sentiment analysis is constructed.A detailed review of existing approaches has been conducted,and a new bilingual sentiment lexicon known as MELex(Malay-English Lexicon)has been *** MELex involves three activities:seed words selection,polarity assignment,and synonym *** approach differs from previous works in that MELex can analyze text for the two most widely used languages in Malaysia,Malay,and English,with the accuracy achieved,is 90%.It is evaluated based on the experimentation and case study approaches where the affordable housing projects in Malaysia are selected as case *** finding has given an implication on the ability of MELex to analyze public sentiments in the Malaysian *** novel aspects of this paper are ***,it introduces the new technique in assigning the polarity score,and second,it improves the performance over the classification of mixed language content.

关键词： Machine learning data sciences artificial intelligence opinion mining sentiment analysis sentiment lexicon lexicon-based bilingual lexicon

Growth of ZnO self-converted 2D nanosheet zeolitic imidazolate framework membranes by an ammoniaassisted strategy

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Nano Research 2018年第4期11卷 1850-1860页

作者： Yujia Li Lu Lin Min Tu Pei Nian Ashlee J. Howarth omar K. Farha Jieshan Qiu Xiongfu Zhang State Key Laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology Dalian 116024 China International Institute for Nanotechnology Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA Center for Surface Chemistry and Catalysis KU Leuven-University ofLeuven Leuven Belgium Department of Chemistry Faculty of Science King Abdulaziz University Jeddah Saudi Arabia

Shaping crystalline porous materials such as metal organic frameworks （MOFs） and zeolites into two-dimensional （2D） nanosheet forms is highly desirable for developing high-performance molecular sieving membranes. However, conventional exfoliation-deposition is complex and challenging for the large-scale fabrication of nanosheet MOF tubular membranes. Here, for the first time, we report a direct growth technique by ZnO self-conversion and ammonia assistance to fabricate zeolitic imidazolate framework （ZIF） membranes consisting of 2D nanosheets on porous hollow fiber substrates; the membranes are suitable for large-scale industrial gas separation processes. The proposed fabrication process for ZIF nanosheet membranes is based on the localized self-conversion of a pre-deposited thin layer of ZnO in a ligand solution containing ammonium hydroxide as a modulator. The resulting ZIF 2D nanosheet tubular membrane is highly oriented and only 50 nm in thickness. It exhibits excellent molecular sieving performance, with high H2 permeance and selectivity for H2/CO2 separation. This technique shows great promise in MOF nanosheet membrane fabrication for large-scale molecular sieving applications.

关键词： nanosheet nanosheet membrane metal organic framework membrane oriented growth gas separation