A Comparative Study of Derrida's Binary Opposition in Escher's Day and Night

Resumen: Este estudio ha comparado la teoría de la oposición binaria de Derrida en “Dia y Noche” de Maurits Escher. Las oposiciones binarias son los principios dominantes del mundo material. Sin lugar a dudas, las oposiciones no pueden dejar de reflejarse en el arte humano, especialmente en las ilustraciones visuales. Para el estudio comparativo de la teoría de Derrida con las artes visuales, fue necesario elegir un indicador de trabajo artístico. Así, la pintura "Día y noche" fue seleccionada por Escher como la obra artística más opuesta de la época contemporánea, que muestra las funciones artísticas de la teoría en sintonía con las obras artísticas visuales. Esto se debe a que la forma y el contenido de este trabajo tienen abundantes oposiciones. Los resultados de este estudio, que se realiza mediante método comparativo y analítico, muestran que el número de oposiciones binarias en esta Pintura llega a 7 ítems e incluye contenido y oposición binaria narrativa y se puede ajustar con la teoría de Derrida en términos de generalización a funciones artísticas.Abstract: This article aimed at conducting a comparative study of Derrida’s binary oppositions theory in Maurits Escher’s Day and Night painting, indicating the applicability of the functions of the theory to the visual artistic works. Binary oppositions are among the dominant principles of the material world. Undoubtedly, such oppositions cannot be without their reflections in human art, especially visual illustrations. Sometimes, art reflects these oppositions and contradictions as they are and depicts them in the form of symbols and signs. For the sake of the comparative study of Derrida’s theory with visual arts, it was necessary to choose a seminal artistic work. Hence, the Day and Night painting by Escher was selected as the most opposing artistic work of the contemporary times. This is because the title, form, and content of this work have plenty of oppositions. The results of this study, conducted with the aid of comparative and analytical methods, show that the number of binary oppositions in this Painting reaches to 7 items. In terms of generalization to artistic functions, this includes form and performance (content and validity) binary oppositions, which are applicable to Derrida’s theory

Biofunctional molecules from Citrullus colocynthis: An HPLC/MS analysis in correlation to antimicrobial and anticancer activities

Background: Citrullus colocynthis belongs to Family Cucurbitaceae. It grows widely in Egypt and Sudan and it has been used in folk medicine of Sudan and many other African countries as anti inflammatory, anti diabetic, and antioxidant agent. Objectives: To evaluate the antibacterial, antifungal, antiviral, anticancer activities of ethanolic crude extracts of the fruits, leaves, seeds and roots of this plant, as well as identifying them HPLC/MS. Materials and Methods: Dried fruits, seeds, leaves and roots of C. colocynthis were powdered and passed through a 40- mesh, then, the powders were extracted with 95% ethanol in a soxhlet apparatus. The residues were dried under reduced pressure in rotary evaporator. Crude extract from different plant parts were evaluated biologically and phytochemically. Results: All extracts showed good antifungal activities with inhibition zone ranges between 15.1 ± 0.32 to 25.6 ± 0.16 mm. In terms of plant organ, fruits were the most active. In term of fungal strain Aspergillus fumigatus and Geotricum candidum were the most sensitive. Against tested Gram +ve, all extracts showed good activities except roots, while antibacterial activity against Gram –ve showed that the fruits extract have good activity as it was the sole extract with activity against Pseudomonas aeruginosa. Test for antiviral activities showed moderate to weak inhibitions of cytopathic effect (CPE). Anticancer activities of different crude extracts showed that fruits had significant antitumor activities against all tested cell lines, the IC50 values were 24.6, 16, 18.5 and 19.7 µg /ml for HCT-116, MCF-7, Hep-G2 and Caco-2 respectively. Seeds extract was only active on HCT-116 and Hep G2 with IC50 =21.2 µg/ml for HCT-116 and 22.4 µg/ml for Hep G2. Leaves extract was only active against Hep G2 cancer cell line with IC50 19.7 µg/ml. Roots extract show weak antitumor activity on tested cell lines (IC50 values > 30µg/ml). HPLC/MS qualitative and quantitative analysis of different organs extracts revealed the presence of 21 compounds identified as fourteen cucurbitacins, three flavonoids, three tannins, and one sterol. The presence of cucurbitacins can explain most of the biological activities. Conclusion: The biological activities of colocynth different parts are due to the presence of secondary metabolites mainly cucurbitacins in addition to flavonoids and tannins.  These activities prove the use of this plant in folk medicine and deserve much more future exploration targeting their discovery in unexplored sources and their derivatives for improving their anticancer and antimicrobial abilities. Keywords: Citrullus colocynthis, crude extracts, antifungal, antibacterial, antiviral, anticancer, HPLC/M

NEW HIDING TECHNIQUE IN DIGITAL SIGNATURE BASED ON ZIGZAG TRANSFORM AND CHAOTIC MAPS

Abstract This paper presents a novel approach to digital signature by integrating the ElGamal or Schnorr digital signature algorithms, chaotic systems, and scanning techniques. Briefly, ZZBCRP is a zigzag transformation that is used firstly to construct a permuted transaction, which technique starts from any random position and intersects in both directions, which is more complex than zigzag transform techniques. Then using ElGamal or Schnorr signature schemes based on chaotic maps. This modification aims to make private key and random number dependent on discrete chaotic maps. Even if the private key chosen is small, it is easy by using the huge amount of points in chaotic maps 2-D or 3-D to extract strong and unique key. This change complicates the relationship between the private key, public key and the transaction signature. A two-dimensional trigonometric discrete chaotic map is used that integrated Logistic-sine-cosine maps, and a three-dimensional hyperchaotic map (3-D SCC) which are based on a sine map. Our performance analysis shows that compared to schemes; this scheme not only improves the level of efficiency but also assures safety. The performance analysis shows that our scheme is not only more efficient compared to other related systems, but also safer

Perception and attitude of physicians toward local generic medicines in Saudi Arabia: A questionnaire-based study

AbstractObjectives: The current study aimed to explore the knowledge, perception, and attitude of physicians toward generic medicines in Saudi Arabia.Background: The local market of generic medicine share in Saudi Arabia is low compared to global and regional statistics. The reason for this low market share and the role of physicians has not previously been investigated. The purpose of this study was to assess health practitioner level of perceived knowledge, opinions and attitudes about local generic medication, and identify factors that influence infrequency of generic prescriptions.Methods: A random sample of 231 physicians was recruited from two hospitals in Riyadh (one government one private) and 178 (77%) responded. Information on the physicians’ perceived knowledge, opinions and attitude toward local generic medication was extracted, analyzed and interpreted. Factors that influence infrequent prescription of local generic drugs were identified.Results: Among the 178 participants in the physicians’ survey, 76% and 47% reported that they are knowledgeable about the terms “generic” and “bioequivalence” respectively, while 44% reported that they are able to explain bioequivalence to their patients. Approximately 52% of physicians reported that local generics should be substituted for brands if suitable for the case, and 21.9% reported that they believe SFDA approved local generics are therapeutically equivalent to their brands. Clinical effectiveness was reported by 71.9% of physicians as the most influential factor effecting prescription of brand over local generic medication. The three independent significant predictors for infrequent prescription of local generics among physicians: Government sector employment (OR=3.74, [95%CI 1.50–9.43]), consultant level (OR=3.94, [95%CI 1.50–10.31]) and low level of knowledge about local generics (OR=4.11, [95%CI 1.56–10.84]).Conclusion: The low market share of local generics medicines attributed to low prescription rates is significantly more among senior-level physicians working in governmental hospitals. Low level of knowledge about generic drugs among physicians was the strongest predictive factor for low prescription. Future bigger studies are needed to confirm these results

Finite-Element Model for Pretensioned Prestressed Concrete Girders

This paper presents a nonlinear model for pretensioned prestressed concrete girders. The model consists of three main components: a beam-column element that describes the behavior of concrete, a truss element that describes the behavior of prestressing tendons, and a bond element that describes the transfer of stresses between the prestressing tendons and the concrete. The model is based on a two-field mixed formulation, where forces and deformations are both approximated within the element. The nonlinear response of the concrete and tendon components is based on the section discretization into fibers with uniaxial hysteretic material models. The stress transfer mechanism is modeled with a distributed interface element with special bond stress-slip relation. A method for accurately simulating the prestressing operation is presented. Accordingly, a complete nonlinear analysis is performed at the different stages of prestressing. Correlation studies of the proposed model with experimental results of pretensioned specimens are conducted. These studies confirmed the accuracy and efficiency of the model

A Review of Basic Mechanical Behavior of Laminated Bamboo Lumber

Over the past decade, the physical and mechanical performances of laminated bamboo lumber (LBL)–a bamboobased structural material, have been extensively studied using experimental, analytical, and numerical approaches. This paper presents a review of existing knowledge in the literature about the mechanical properties of LBL. The paper involved the review of the response of LBL to different types of loading such as tension, bending, compression, and shear. Based on results of the literature reviewed, the strength of LBL parallel to grain was 90–124 MPa with MOE of 10700 MPa in tension, 29.55–72.60 MPa, and MOE of 8396–11022 MPa in compression, 63.87– 128.4 MPa, and MOE of 8320–10912 MPa in bending, and 7.15–17.5 MPa in shear. The average strength of LBL was similar and in some cases exceeded the average values of bamboo- or wood-based materials, while the variability of its mechanical parameters was lower. The variability in strength values of LBL was affected by bamboo species, density and thickness of bamboo strips, growth portion, type of treatment, strips arrangements, and type of adhesive which in turn calls for classification of LBL by strength grades, degree of hardness, the capability of impregnation and penetration, as well as by areas of application in construction. The study provided and discussed concluding observations, the current research gap, and future research directions on the mechanical properties of LBL

Green nanotechnology: Anticancer Activity of Silver Nanoparticles using Citrullus colocynthis aqueous extracts

Green synthesis of metal nanoparticles is a growing research area because of their potential applications in nanomedicines. The green synthesis of silver nanoparticles (SNPs) is a convenient, cheap and environmentally safe approach compared to chemical synthesis. In the present study, we synthesized SNPs from AgNO3 using aqueous extracts (AEs) of fruits, leaves, roots and seeds of Citrullus colocynthis as reducing and capping agents. The SNPs were early detected in the aqueous extracts by color change to the reddish brown, and further were confirmed by Transmission Electron Microscope (TEM) analysis. The TEM analysis of SNPs showed spherical nanoparticles with mean size between 7 to 19nm. The anticancer activity of SNPs has been assessed invitro.  MTT assay on human cancer cell lines of colon (HCT-116), breast (MCF-7), liver (Hep-G2) and intestine (Caco-2) showed good anticancer activity which was negligible for the aqueous plant extracts. Regarding to the tested cell lines the Hep-G2 cell line and HCT-116 were the most sensitive cell line towards the cytotoxic activities of the tested SNPs, while the Caco-2 was the most resistant cell line towards the cytotoxic activities. Keywords: green synthesis, silver nanoparticles, Citrullus colocynthis, anticancer

Simultaneous Determination of TetracyclinesResidues in Bovine Milk Samples by Solid Phase Extraction and HPLC-FL Method

Introduction:Tetracyclines (TCs) are widely used in animal husbandry and their residues in milk may resultinharmful effects on human. The aim of this study was to investigate the presence of TCs residues in various bovine milk samples from local markets of Ardabil, Iran. Methods:One hundred and fourteen pasteurized, sterilized and raw milk samples were collected from markets of Ardabil. Tetracycline, Oxytetracycline and Chlortetracycline (TCs) residues extraction carried out by Solid Phase Extraction method. Determination of TCs residues were performed by high performance liquid chromatography (HPLC) method using Fluorescence detector.Results: The mean of total TCs residues in all samples (114 samples) was 97.6 ±16.9ng/g and that of pasteurized, sterilized and raw milk samples were 87.1 ± 17.7, 112.0 ± 57.3 and 154.0 ± 66.3ng/g respectively. Twenty five point four percent of the all samples, and24.4%, 30% and 28.6% of the pasteurized, sterilized and raw milk samples, respectively had higher TCs residues than the recommended maximum levels (100ng/g). Conclusion:This study indicates the presence of tetracycline residues more than allowed amount. Regulatory authorities should ensure proper withdrawal period before milking the animals and definite supervisions are necessary on application of these drugs