OALib Journal期刊

ISSN: 2333-9721



匹配条件: “ Khulud Alshehri” ,找到相关结果约43条。
Effect of Cadmium Repartition on Nitrogen Metabolism in Tobacco Seedlings  [PDF]
Houda Maaroufi Dguimi, Khulud Alshehri, Chokri Zaghdoud, Ali Khalaf Albaggar, Mohamed Debouba
Open Access Library Journal (OALib Journal) , 2019, DOI: 10.4236/oalib.1104000
Thirty-day-old tobacco seedlings (Nicotiana tabaccum, Bureley v) were subjected during one week to increasing cadmium (Cd) concentrations (0, 10, 20, 50 and 100 μM CdCl2). Increasing Cd stress led to a gradual decrease of dry weight (DW) production, water and nitrate contents. More than the half of Cd accumulated per plant was sequestered in the oldest leaf stage (S1 leaves). Leaves from S1 were the least affected by Cd stress. The activities of nitrate reductase (NR, EC, nitrite reductase (NiR, EC were the least reduced in S1 leaves despite of the high presence of Cd ions. At 100 μM Cd, glutamine synthetase activity (GS, EC from S1 leaves rose to become 2 times more important than control. Western Blot analysis showed that S1 GS activity induction was correlated to the GS1 and GS2 protein accumulation. Young leaves (S3 leaves) were more affected by Cd stress than old leaves. The GS activity reduction in S3 leaves was correlated to GS2 protein decrease detected by western-blot analysis. So, tobacco plant accumulated Cd ions in old leaves (S1 leaves) to protect younger leaves which are more sensitive to Cd effects. Leaves from S1 are a target organ to verify an eventual soil contamination per cadmium. This leaves may evolve adaptive process to partially inactivate Cd ions and maintain stable rate of nitrogen metabolism.
Non-Stationary Signal Segmentation and Separation from Joint Time-Frequency Plane  [PDF]
Abdullah Ali Alshehri
Journal of Signal and Information Processing (JSIP) , 2012, DOI: 10.4236/jsip.2012.33043
Abstract: Multi-components sinusoidal engineering signals who are non-stationary signals were considered in this study since their separation and segmentations are of great interests in many engineering fields. In most cases, the segmentation of non-stationary or multi-component signals is conducted in time domain. In this paper, we explore the advantages of applying joint time-frequency (TF) distribution of the multi-component signals to identify their segments. The Spectrogram that is known as Short-Time Fourier Transform (STFT) will be used for obtaining the time-frequency kernel. Time marginal of the computed kernel is optimally used for the signal segmentation. In order to obtain the desirable segmentation, it requires first to improve time marginal of the kernel by using two-dimensional Wiener mask filter applied to the TF kernel to mitigate and suppress non-stationary noise or interference. Additionally, a proper choice of the sliding window and its overlaying has enhanced our scheme to capture the discontinuities corresponding to the boundaries of the candidate segments.
Importance of Ankle/Brachial Pressure Index in Saudi Patients with Coronary Artery Disease  [PDF]
Abdullah M. Alshehri, Mohamed Elsharawy
World Journal of Cardiovascular Surgery (WJCS) , 2013, DOI: 10.4236/wjcs.2013.36036
Abstract: Background: The ankle/brachial pressure index (ABPI) has been shown to be a good marker of systemic atherosclerosis and a powerful predictor of cardiovascular morbidity and mortality. The objective of this study was to determine the importance of measuring ABPI in Saudi patients with coronary artery disease (CAD). METHODS: This is a hospital based cross-sectional study which was conducted on all Saudi patients who underwent coronary angiography without symptoms of peripheral arterial disease at King Fahd Hospital of the University, Al-Khobar Saudi Arabia. All patients underwent measurement of their ABPI. The study was carried out between December 2010 and November 2011. RESULTS: During the study period, two hundred and five patients were included. Fifty-nine (28.8%) patients were Group II (ABPI ≤ 0.90) and the rest was Group I (ABPI > 0.90). Significant correlation was also found between low ABPI and the extent of CAD (mean number of arteries involved in Group I was 1.78 ± 0.83 compared to 2.10 ± 0.736 in Group II p = 0.011). Nevertheless, the correlation between low ABPI, and the severity of presentation of CAD were also significant (Incidence of myocardial infarction with congestive heart failure was 0.5% in Group I compared to 12% in Group II p < 0.001). CONCLUSION: The ABPI is an important prognostic indicator for Saudi patients with CAD.
Derivations of MV-Algebras
N. O. Alshehri
International Journal of Mathematics and Mathematical Sciences , 2010, DOI: 10.1155/2010/312027
Abstract: We introduce the notion of derivation for an MV-algebra and discuss some related properties. Using the notion of an isotone derivation, we give some characterizations of a derivation of an MV-algebra. Moreover, we define an additive derivation of an MV-algebra and investigate some of its properties. Also, we prove that an additive derivation of a linearly ordered MV-algebral is an isotone. 1. Introduction In his classical paper [1], Chang invented the notion of MV-algebra in order to provide an algebraic proof of the completeness theorem of infinite valued Lukasiewicz propositional calculus. Recently, the algebraic theory of MV-algebras is intensively studied, see [2–5]. The notion of derivation, introduced from the analytic theory, is helpful to the research of structure and property in algebraic system. Several authors [6–9] studied derivations in rings and near rings. Jun and Xin [10] applied the notion of derivation in ring and near-ring theory to BCI-algebras. In [11], Szász introduced the concept of derivation for lattices and investigated some of its properties, for more details, the reader is referred to [9, 12–19]. In this paper, we apply the notion of derivation in ring and near-ring theory to MV-algebras and investigate some of its properties. Using the notion of an isotone derivation, we characterize a derivation of MV-algebra. We introduce a new concept, called an additive derivation of MV-algebras, and then we investigate several properties. Finally, we prove that an additive derivation of a linearly ordered MV-algebra is an isotone. 2. Preliminaries Definition 2.1 (see [5]). An MV-algebra is a structure where is a binary operation, is a unary operation, and 0 is a constant such that the following axioms are satisfied for any : (MV1) is a commutative monoid,(MV2) ,(MV3) ,(MV4) . If we define the constant and the auxiliary operations , and by then is a commutative monoid and the structure is a bounded distributive lattice. Also, we define the binary operation by . A subset of an MV-algebra is called subalgebra of if and only if is closed under the MV-operations defined in . In any MV-algebras, one can define a partial order ≤ by putting if and only if for each . If the order relation ≤, defined over , is total, then we say that is linearly ordered. For an MV-algebra , if we define . Then, is both a largest subalgebra of and a Boolean algebra. An MV-algebra has the following properties for all (1) ,(2) ,(3) , (4)If , then ,(5)If , then ,(6)If , then and ,(7)If , then and ,(8) if and only if ,(9) if and only if . Theorem 2.2 (see [1]). The
New Thermal and Microbial Resistant Metal-Containing Epoxy Polymers
Tansir Ahamad,Saad M. Alshehri
Bioinorganic Chemistry and Applications , 2010, DOI: 10.1155/2010/976901
Abstract: A series of metal-containing epoxy polymers have been synthesized by the condensation of epichlorohydrin (1-chloro-2,3-epoxy propane) with Schiff base metal complexes in alkaline medium. Schiff base was initially prepared by the reaction of 2,6 dihydroxy 1-napthaldehyde and o-phenylenediamine in 1??:??2 molar ratio and then with metal acetate. All the synthesized compounds were characterized by elemental, spectral, and thermal analysis. The physicochemical properties, viz., epoxy value, hydroxyl content, and chlorine content [mol/100?g] were measured by standard procedures. The antimicrobial activities of these metal-containing epoxy polymers were carried out by using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods against S. aureus, B. subtilis (Gram-positive bacteria), and E. coli, P. aeruginosa (Gram-negative bacteria). It was found that the ECu(II) showed higher antibacterial activity than other metal-chelated epoxy resin while EMn(II) exhibited reduced antibacterial activity against all bacteria. 1. Introduction Since the last two decades, several thermal and microbial resistant polymers have been synthesized by the immobilization of metal complexes into the polymers [1] and used as a thermal resistant, microbial resistant, scratch resistant, and flame retardant-coating materials. Some metal complexes commonly used in the synthesis of metal containing polymers are Schiff base, ferrocene, Imidazole, secondary and tresiory amine metal complexes, and so forth, [2, 3]. Among these metal complexes Schiff base metal complexes have been widely used due to their corrosive resistant, microbial as well as thermal resistant properties [4]. Epoxy polymers are one of the most important higher-performance polymer systems in use today, ranging from simple two-part adhesives and sports equipment to high-tech applications such as formula one racing cars and the aerospace industry. Epoxy polymers are capable of undergoing homopolymerisation, although this process generally yields products with inadequate properties for high-tech applications. Consequently, in many cases catalysts, additives, and cocuring-agents are formulated with the epoxy resin to significantly increase the storage stability, decrease the cure time, and improve the final properties [5, 6]. The use of metals to formulate resin systems with excellent storage stability is discussed, along with the use of coordination compounds to improve cured resin properties such as fracture toughness, thermal stability, and water absorption [7, 8]. Two approaches are
UWB Imaging for Breastr Cancer Detection Using Neural Network
Saleh Ali AlShehri;Sabira Khatun
PIER C , 2009, DOI: 10.2528/PIERC09031202
Abstract: This paper presents a simple feed-forward back-propagation Neural Network (NN) model to detect and locate early breast cancer/tumor efficiently through the investigation of Electromagnetic (EM) waves. A spherical tumor of radius 0.25 cm was created and placed at arbitrary locations in a breast model using an EM simulator. Directional antennas were used to transmit and receive Ultra-Wide Band (UWB) signals in 4 to 8 GHz frequency range. Small training and validation sets were constructed to train and test the NN. The received signals were fed into the trained NN model to find the presence and location of tumor. Very optimistic results (about 100% and 94.4% presence and location detection rate of tumor respectively) have been observed for early received signal components with the NN model. Hence, the proposed model is very potential for early tumor detection to save human lives in the future.
Prediction of Reservoir Performance Applying Decline Curve Analysis
Khulud M. Rahuma,H. Mohamed,N. Hissein,S. Giuma
International Journal of Chemical Engineering and Applications , 2013, DOI: 10.7763/ijcea.2013.v4.266
Abstract: Decline curve analysis is a technique can be applied to a single well, and total reservoir. Decline analysis routinely used by engineers to estimate initial hydrocarbon in place, hydrocarbon reserves at some abandonment conditions, and forecasting future production rate. The remaining reserve depends on the production points that selected to represent the real well behavior, the way of dealing with the production data, and the human errors that might happen during the life of the field. In this study the actual oil rate technique is applied under decline curve analysis (D.C.A) program, and screening data points to calculate remaining and recoverable reserves.
Efficacy of nebulized furosemide in children with moderate attack of asthma
M Alshehri, T Almegamesi, A Alfrayh
West African Journal of Medicine , 2005,
On t derivations of incline algebras
N. O. Alshehri,H. S. Alqahtani
International Mathematical Forum , 2013,
Abstract: In this paper, we introduce the notion of t derivations of inclinealgebras and investigate some of their properties. Moreover, we showthat if a t derivation is nonzero on an integral incline K, then it isnonzero on any nonzero ideals of K.
On derivations of BCC-algebras
N. O. Alshehri,S. M. Bawazeer
International Journal of Algebra , 2012,

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