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Rice melatonin deficiency causes premature leaf senescence via DNA methylation regulation

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The Crop Journal 2024年第3期12卷 721-731页

作者： Yue Lu ahmed Gharib Rujia Chen Hanyao Wang Tianyun Tao Zhihao Zuo Qing Bu Yanze Su Yaoqing Li Yanmo Luo hamdi F.El-Mowafi Zhichao Wang Qianfeng Huang Shuting Wang Yang Xu Pengcheng Li Chenwu Xu Zefeng Yang Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Zhongshan Biological Breeding Laboratory/Key Laboratory of Plant Functional Genomics of the Ministry of Education Agriculture College of Yangzhou UniversityYangzhou 225009JiangsuChina Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops Jiangsu Key Laboratory of Crop Genetics and PhysiologyYangzhou UniversityYangzhou 225009JiangsuChina National Institute of Laser Enhanced Sciences(NILES) Cairo UniversityGiza 12613Egypt Rice Research Department Field Crops Research InstituteAgricultural Research CenterSakhaKafr El-Sheikh 33717Egypt

In a study of DNA methylation changes in melatonin-deficient rice mutants,mutant plants showed premature leaf senescence during grain-filling and reduced grain *** deficiency led to transcriptional reprogramming,especially of genes involved in chlorophyll and carbon metabolism,redox regulation,and transcriptional regulation,during dark-induced leaf *** of mCG and mCHG in the melatonin-deficient rice mutants was associated with the expression change of both protein-coding genes and transposable element-related *** in gene expression and DNA methylation in the melatonin-deficient mutants were compensated by exogenous application of melatonin.A decreased S-adenosyl-L-methionine level may have contributed to the DNA methylation variations in rice mutants of melatonin deficiency under dark conditions.

关键词： Melatonin Premature leaf senescence Rice DNA methylation Epigenetic regulation

Replacement of alkali silicate solution with silica fume in metakaolin-based geopolymers

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 555-564页

作者： ahmed Nmiri Myriam Duc Noureddine hamdi Oumaya Yazoghli-Marzouk Ezzeddine Srasra National Center for Research in Materials Sciences Technop?le Borj Cedria (CNRSM) Department of Chemistry Faculty of Sciences of Tunis University of Tunis El-Manar French Institute of Science and Technology for Transport Development and Networks (IFSTTAR) Center for Studies and Expertise on Risks Environment Mobility and Development (CEREMA)

A metakaolin(Mk)-based geopolymer cement from Tunisian Mk mixed with different amounts of silica fume(SiO_2/Al_2O_3 molar ratio varying between 3.61 and 4.09) and sodium hydroxide(10M) and without any alkali silicate solution, is developed in this work. After the samples were cured at room temperature under air for 28 d, they were analyzed by X-ray diffraction(XRD), Fourier transform infrared(FTIR) spectroscopy, environmental scanning electron microscopy, mercury intrusion porosimetry, ^(27)Al and ^(29)Si nuclear magnetic resonance(NMR) spectroscopy, and compression testing to establish the relationship between microstructure and compressive strength. The XRD, FTIR, and ^(27)Al and ^(29)Si NMR analyses showed that the use of silica fume instead of alkali silicate solutions was feasible for manufacturing geopolymer cement. The Mk-based geopolymer with a silica fume content of 6 wt%(compared with those with 2% and 10%), corresponding to an SiO_2/Al_2O_3 molar ratio of 3.84, resulted in the highest compressive strength, which was explained on the basis of its high compactness with the smallest porosity. Silica fume improved the compressive strength by filling interstitial voids of the microstructure because of its fine particle size. In addition, an increase in the SiO_2/Al_2O_3 molar ratio, which is controlled by the addition of silica fume, to 4.09 led to a geopolymer with low compressive strength, accompanied by microstructures with high porosity. This high porosity, which is responsible for weaknesses in the specimen, is related to the amount of unreacted silica fume.

关键词： metakaolin silica fume geopolymer cement compressive strength

Blockchain Mobile Wallet with Secure Offline Transactions

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Computers, Materials & Continua 2023年第5期75卷 2905-2919页

作者： Raed Saeed Rasheed Khalil hamdi Ateyeh Al-Shqeerat ahmed Salah Ghorab Fuad Salama AbuOwaimer Aiman ahmed AbuSamra Faculty of Engineering Islamic University of GazaP.O.Box 108GazaPalestine Department of Computer Science College of ComputerQassim UniversityP.O.Box 52211BuraydahSaudi Arabia University College of Applied Sciences P.O.Box 1415GazaPalestine Palestine Technical College P.O.Box 6037Deir ElBalahPalestine

There has been an increase in the adoption of mobile payment systems worldwide in the past few ***,poor Internet connection in rural regions continues to be an obstacle to the widespread use of such *** top of that,there are significant problems with the currently available offline wallets;for instance,the payee cannot verify the number of coins received without access to the ***,it has been demonstrated that some existing systems are susceptible to false token generation,and some do not even permit the user to divide the offline token into smaller portions to be used as *** paper proposes a blockchainbased wallet system that provides a secure mobile payment service even if a user cannot access a reliable Internet *** approach relies on Bluetooth and digital signatures to establish and build a trust connection between the *** proposed solution overcomes the main limitations of existing systems that use offline transactions,such as the generation of fake offline tokens and the indivisibility of offline *** user buys Offline Tokens(OTs)from a server called an Offline Token Manager(OTM)to use them later to perform offline *** mobile device must store a single,signed offline token transaction to prevent fake *** the other hand,all offline transactions will be kept as a history in a particular local ***,when the receiver becomes online,it will send a convert request to the OTMto change the value of the OTs to the appropriate amount in real *** step requires a connection to the *** evaluate the effectiveness of the system,the Solidity programming language was used to develop a smart contract on the Ethereum blockchain with a backend application programming interface(API)and an android mobile *** proposed method has an advantage over other prominent wallets.

关键词： Mobile wallet blockchain smart contracts digital signature

Research of the Vortex-induced Vibration and Aerodynamic Countermeasures on a Cable-stayed Bridge with Π-shaped Main Girder Section

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Research of the Vortex-induced Vibration and Aerodynamic Cou...

作者： NAJI hamdi NAJIB ahmed 湖南大学

学位级别：硕士

由于Ⅱ型断面斜拉桥具有施工方便、建设周期短和自重较轻等特点,近年来得到广泛应用。该类桥型主跨通常在200～600m,但由于其主梁为开口截面,具有明显的钝体特性,在风荷载作用下,尾流中易产生周期性旋涡脱落,又因其质量较轻,抗扭刚度较... 详细信息

由于Ⅱ型断面斜拉桥具有施工方便、建设周期短和自重较轻等特点,近年来得到广泛应用。该类桥型主跨通常在200～600m,但由于其主梁为开口截面,具有明显的钝体特性,在风荷载作用下,尾流中易产生周期性旋涡脱落,又因其质量较轻,抗扭刚度较小,气动稳定性较差,以至于该类桥梁在低风速下容易发生涡激振动。虽然涡激振动是一种限幅振动,不会引起结构毁灭性破坏,但其发生风速较低,振幅过大可能引起结构疲劳问题和行人行车安全性及舒适性问题。因此,研究Ⅱ型断面斜拉桥涡激振动特性及气动抑制措施具有较大意义和实际工程价值。本文结合节段模型风洞试验,研究了Ⅱ型主梁断面的静气动力系数、涡激振动特性及气动控制措施,并结合数值模拟对涡激振动及控制机理进行了分析,具体包括如下几方面内容:(1)对在建的潮汕大桥进行节段模型风洞试验,测得原始主梁断面的涡激振动响应,结果表明:Ⅱ型钢-混凝土结合梁断面原设计方案在+3°攻角下,当实桥桥面高度处风速为30.0～50.0m/s时,存在明显的竖向涡激共振现象,最大振幅为0.25m,超过规范允许值,不能满足要求。(2)对潮汕大桥原始断面发生的涡激振动,采取气动控制措施对其进行抑制,并考虑附属设施对涡激振动性能的影响,结果表明:通过采取三道加高后的下稳定板、两侧竖向裙板及增大阻尼比后的组合气动控制措施后,主梁断面的涡激振动性能满足规范要求;采取气动控制措施后的主梁断面在施工状态下的涡激振动性能满足规范要求。增加附属设施后,在风攻角为α=+3°下,成桥状态主梁断面发生了大幅扭转涡振现象,振幅不能满足规范要求,而增大紊流度至Iu=3.0%后,主梁断面成桥状态未观测到明显的涡激振动现象。(3)针对采取气动控制措施的主梁断面进行了测力试验,并基于风洞试验参数,建立主梁断面CFD二维数值模型。将CFD计算所得静气动力系数与风洞试验结果进行比对,说明了数值模拟的准确性;而后计算分析了潮汕大桥Ⅱ型主梁断面静态绕流情况,并对主梁断面涡激振动及制振机理进行了分析,计算结果表明:原设计方案主梁断面上、下表面的压力差是导致涡激振动的关键因素,同时与尾流区卡门涡街形成的周期性压力差共同作用导致主梁原设计方案断面产生较大的竖向涡激力,从而引起主梁断面发生竖向涡激共振现象;设置三道下稳定板可将有效破坏Ⅱ型主梁下侧较大旋涡,Ⅱ型主梁两侧设置竖直裙板改善了其气动流线型程度,设置上中央稳定板可有效阻止主梁上侧较大旋涡的运动。(4)基于潮汕大桥主梁断面参数,设计了两类不同开口宽度的裸梁断面,并通过CFD计算得到了两类不同开口宽度裸梁断面的静气动力系数,计算结果表明:在+3°攻角下,相较于潮汕大桥主梁断面,减小开口宽度至17.5m后,阻力系数减小而升力系数及扭矩系数增大;增大开口宽度至31.5m后,阻力系数及升力系数增大而扭矩系数减小。

关键词：斜拉桥 Π型断面静气动力系数涡激振动气动控制措施风洞试验数值模拟

Ultra Wide Band Multiple Access by Using DS-BPSK

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Ultra Wide Band Multiple Access by Using DS-BPSK

作者： Ali hamdi ahmed Rajeh 湖南大学

学位级别：硕士

根据流行的定义,任何能产生带宽超过500MHz或者分数带宽大于0.2的信号的无线通信技术,均可被认为是超宽带技术。超宽带技术允许在3.1到10.6GHz的无牌照频谱区间以较低的平均功耗和兆比特每秒的速率传送数据。目前存在几种脉冲波形,... 详细信息

根据流行的定义,任何能产生带宽超过500MHz或者分数带宽大于0.2的信号的无线通信技术,均可被认为是超宽带技术。超宽带技术允许在3.1到10.6GHz的无牌照频谱区间以较低的平均功耗和兆比特每秒的速率传送数据。目前存在几种脉冲波形,如高斯型双合透镜脉冲波形,高斯单环脉冲波形（Gaussian Monocycle Pulse Shape）,高斯脉冲波形以及矩形脉冲波形。脉冲波形的选择将会影响到系统的性能,因为超宽带波形需要占用大量的带宽。我们将在多用户和多径环境下研究超宽带系统的性能,而这种环境需要用到像跳时扩频或直接序列扩频这样著名的多路存取的扩频技术,特别是在蜂窝移动无线通信中,因为这时多个用户是在像脉冲幅度调制、脉冲位置调制和移相键控等调制方式下,共享互不干扰的同一频带。在本文的研究中,将用到直接序列扩频-二进制移相键控技术,它表明直接序列多址技术将有可能达到更高的数据传输速率。首先将在单用户和加性高斯白噪声信号下验证超宽带系统的性能,然后再在有干扰的多用户下验证。对一个具有10个用户,采用层次化结构的网络进行仿真,并构造了一个31位长度的编码。

关键词： UWB MAI DSBPSK

Furuncular myiasis by Wohlfahrtia magnifica(Diptera:Sarcophagidae)in a healthy child

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Asian Pacific Journal of Tropical Medicine 2022年第2期15卷 87-89页

作者： Majed hamdi Wakid Angham ahmed Almakki Nouf Saleh Alsahaf Mohammed Ali Almatrafi King Abdulaziz University Faculty of Applied Medical SciencesDepartment of Medical Laboratory TechnologyJeddahSaudi Arabia Special Infectious Agent Unit King Fahd Medical Research CenterKing Abdulaziz UniversityJeddahSaudi Arabia Department of Laboratory and Blood Bank Security Forces HospitalMakkahSaudi Arabia Medical College Umm Al Qura UniversityMakkahSaudi Arabia Department of Pediatrics Umm Al Qura UniversityMakkahSaudi Arabia Department of Pediatrics Security Forces HospitalMakkahSaudi Arabia

Rationale:Human myiasis is the invasion of tissue or organs by fly *** could be obligatory,facultative,or *** concerns:A 4-year-old Saudi boy complained of fever over the past three days with multiple inflamed painful dermal furuncles and worms-like ***:Furuncular obligatory myiasis caused by Wohlfahrtia ***:Maggots were removed for *** wounds were cleaned with antiseptic *** and oral antibiotics were ***:Seven days later,the wounds completely ***:Although several reports correlated human myiasis with old age,low health status,mental retardation,and low socioeconomic status,but the patient in our case was a healthy child from a family with good socioeconomic status,good hygiene,no history of diseases or mental disability,but traveled to a village where the climate is suitable for fly breeding.

关键词： Furuncule Myiasis Wohlfahrtia magnifica Maggots Saudi Arabia

A Hybrid Feature Selection Framework for Predicting Students Performance

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Computers, Materials & Continua 2022年第1期70卷 1893-1920页

作者： Maryam Zaffar Manzoor ahmed Hashmani Raja Habib KS Quraishi Muhammad Irfan Samar Alqhtani Mohammed hamdi High Performance Cloud Computing(HPC3) Department of Computer and Information SciencesUniversiti Teknologi PETRONAS32610SeriIskandarMalaysia Department of Computer Science and Information Technology University of LahorePakistan Department of Process Engineering Pakistan Institute of Engineering&Applied SciencesNiloreIslamabadPakistan Electrical Engineering Department College of EngineeringNajran UniversityNajran61441Saudi Arabia College of Computer Science and Information Systems Najran University61441NajranSaudi Arabia

Student performance prediction helps the educational stakeholders to take proactive decisions and make interventions,for the improvement of quality of education and to meet the dynamic needs of *** selection of features for student’s performance prediction not only plays significant role in increasing prediction accuracy,but also helps in building the strategic plans for the improvement of students’academic *** are different feature selection algorithms for predicting the performance of students,however the studies reported in the literature claim that there are different pros and cons of existing feature selection algorithms in selection of optimal *** this paper,a hybrid feature selection framework(using feature-fusion)is designed to identify the significant features and associated features with target class,to predict the performance of *** main goal of the proposed hybrid feature selection is not only to improve the prediction accuracy,but also to identify optimal features for building productive strategies for the improvement in students’academic *** key difference between proposed hybrid feature selection framework and existing hybrid feature selection framework,is two level feature fusion technique,with the utilization of cosine-based ***,according to the results reported in existing literature,cosine similarity is considered as the best similarity measure among existing similarity *** proposed hybrid feature selection is validated on four benchmark datasets with variations in number of features and number of *** validated results confirm that the proposed hybrid feature selection framework performs better than the existing hybrid feature selection framework,existing feature selection algorithms in terms of accuracy,f-measure,recall,and *** reported in presented paper show that the proposed approach gives more than 90%accuracy on benchmark dataset that is better tha

关键词： Educational data mining feature selection hybrid feature selection

Naturally Nitrogen-Doped Biochar Made from End-of-Life Wood Panels for SO_(2) Gas Depollution

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Journal of Renewable Materials 2023年第11期11卷 3807-3829页

作者： hamdi Hachicha Mamadou Dia Hassine Bouafif ahmed Koubaa Mohamed Khlif Flavia Lega Braghiroli Research Forest Institute(Institut de Recherche sur les Forets IRF)University of Quebec in Abitibi-Temiscamingue(UQAT)Rouyn-NorandaQC J9X 5E4Canada Technology Center for Industrial Waste(Centre Technologique des Residus Industriels CTRI)College of Abitibi-Temiscamingue(Cégep de L’Abitibi-Témiscamingue)Rouyn-NorandaQC J9X 5E5Canada Ecole D’ingenieur de Sfax Universite de SfaxSfax3038Tunisia

Reconstituted wood panels have several advantages in terms of ease of manufacturing,but their shorter life span results in a huge amount of reconstituted wood panels being discarded in sorting centers ***,the most common approach for dealing with this waste is *** this study,reconstituted wood panels were converted into activated biochar through a two-step thermochemical process:(i)biochar production using pilot scale fast pyrolysis at 250 kg/h and 450℃;and(ii)a physical activation at three temperatures(750℃,850℃ and 950℃)using an in-house activation furnace(1 kg/h).Results showed that the first stage removed about 66% of the nitrogen from the wood panels in the form of NO,NH3,and trimethylamine,which were detected in small amounts compared to emitted CO_(2).Compared to other types of thermochemical conversion methods(e.g.,slow pyrolysis),isocyanic acid and hydrogen cyanide were not detected in this *** second stage produced activated biochar with a specific surface area of up to 865 m^(2)/g at 950℃.The volatile gases generated during activation were predominantly composed of toluene and *** two-step process resulted in nitrogen-rich carbon in the form of pyrrolic and pyridinic *** biochars were then evaluated for their SO_(2) retention performance and showed an excellent adsorption capacity of up to 2140 mg/g compared to 65 mg/g for a commercial activated carbon(889 m^(2)/g).End-of-life reconstituted wood panels and SO_(2) gas are problematic issues in Canada where the economy largely revolves around forestry and mining industries.

关键词： End-of-life wood panels pyrolysis activation biochar and activated biochar N-doped carbons SO_(2)removal

The good,the bad,and the ugly of consumer sleep technologies use among athletes:A call for action

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Journal of Sport and Health Science 2023年第4期12卷 486-488页

作者： Khaled Trabelsi ahmed S.BaHammam hamdi Chtourou Haitham Jahrami Michael V.Vitiello High Institute of Sport and Physical Education of Sfax University of SfaxSfax 3000Tunisia Research Laboratory:Education MotricitySport and HealthUniversity of SfaxSfax 3000Tunisia Department of Medicine College of MedicineUniversity Sleep Disorders CenterKing Saud UniversityRiyadh 2925Saudi Arabia The Strategic Technologies Program of the National Plan for Sciences and Technology and Innovation in the Kingdom of Saudi Arabia RiyadhSaudi Arabia Research Unit:Physical Activity Sportand HealthNational Observatory of SportTunis 1003Tunisia Govermental Hospitals Manama 329Kingdom of Bahrain Department of Psychiatry College of Medicine and Medical SciencesArabian Gulf UniversityManama 329Kingdom of Bahrain Department of Psychiatry&Behavioral Sciences University of WashingtonSeattleWA 98195-6560USA

*** For athletes,the quality and quantity of sleep are essential elements for optimizing recovery and subsequent performance.1 Unfortunately,athletes frequently face challenges getting sufficient,high-quality sleep.2 A recent systematic review and meta-analysis of 81 studies involving 1830 athletes concluded that compared to healthy non-athletes,athletes'sleep duration was shorter with poorer sleep efficiency.

关键词： athletes sleep shorter