Adsorption of Some Alephatic Dicarboxylic Acids on Zinc Oxide: A kinetic and Thermodynamic Study

الهدف من اجراء هذا البحث هو لدراسة ميكانيكية امتزاز حامض المالونيك، حامض السكسنيك، حامض الاديبيك، وحامض الازيلايك من محاليلها المائية على سطح أوكسيد الزنك. حيث تم دراسة كفاءة الامتزاز بالاستعانة بعدة عوامل مختلفة مثل كمية المادة المازة، زمن التماس، التركيز الابتدائي، ودرجة الحرارة. اظهرت النتائج ان الظروف المثلى اللازمة لإزالة الحوامض من محاليلها المائية هي كمية المادة المازة 0.2 غرام، وأفضل زمن للاتزان هو 40 دقيقة، والتركيز الابتدائي للحوامض كان 0.005 مولاري. كما أظهرت الدراسة ان زيادة درجة الحرارة تقلل من كفاءة الامتزاز. ومن خلال تطبيق النماذج الحركية على عملية الامتزاز وجد ان نموذج الرتبة الثانية الكاذبة يعطي علاقة خطية مع معامل ارتباط جيد. كما اشتملت الدراسة على حساب الدوال الثرموداينميكية، حيث أظهرت النتائج ان القيمة السالبة للطاقة الحرة لجبس والتغير في الانثالبي تؤكدان التلقائية والطبيعة الباعثة للحرارة لعملية الامتزاز. لقد وجد ان لاوكسيد الزنك قابلية جيدة على إزالة الحوامض الاليفاتية ثنائية الكاربوكسيل من محاليلها المائية، وان طول السلسلة للحوامض ليس له أي تأثير على امتزازها.The adsorption of Malonic acid, Succinic acid, Adipic acid, and Azelaic acid from their aqueous solutions on zinc oxide surface were investigated. The adsorption efficiency was investigated using various factors such as adsorbent amount, contact time, initial concentration, and temperature. Optimum conditions for acids removal from its aqueous solutions were found to be adsorbent dose (0.2 g), equilibrium contact time (40 minutes), initial acids concentration (0.005 M). Variation of temperature as a function of adsorption efficiency showed that increasing the temperature would result in decreasing the adsorption ability. Kinetic modeling by applying the pseudo-second order model can provide a better fit of the data with a greater correlation coefficient, which indicates that the adsorption process follow the pseudo-second order kinetics. The negative values of Gibbs free energy and the enthalpy change confirm the spontaneous and exothermic nature of the adsorption process. A good ability of zinc oxide to remove aliphatic dicarboxylic acids from its aqueous solutions has been found, and the chain length of the acids has no significant effect on its adsorption

Real-Time PCR Quantification of Metallothionein Gene Expression in Sprague–Dawley Rats Chronically Exposed to Cd

Toxicologic impact of Cd leads to multiple human pathologic conditions, and its effect on humans and animals has been extensively studied. Physiologic function of metallothionein (MT1) is not completely understood, but it is mainly associated with detoxification of Cd and Hg. Elevated synthesis of MT1 exposed to metals has been observed but data on quantitation in various tissues is limited. We measured MT1 levels in peripheral blood and tissue samples of rats exposed to CdCl2. The objective is to investigate the effect of chronic exposure of Cd on peripheral blood and tissue-specific expression of MT1. This will provide information of MT1 gene transcription regulation and its impact on the heavy metal detoxification process. Rats raised in our animal facility were assigned to 8 experimental groups. Daily dose of 15 mg/ kg body weight CdCl2 in drinking water was administered for 8 wk. The control group received tap water free of Cd. Peripheral blood samples collected at 4 occasions (week 2, 4, 6, and 8) in EDTA tubes by retroorbital bleeding procedure. Liver and kidney tissue samples were collected and weighed. Total RNA/cDNA was prepared and quantified according to manufacturer’s protocol. Premade MT1 gene expression assay was used while β-actin gene was the endogeneous control. Results from week 2 and 4 showed the trend of upregulation of MT1 gene (fold increase) while the sample from all the other occasions showed downregulated response of MT1. Week 4 sample showed the fold increase of 1.11 times compared to week 2 increase of 1.04. Though the recorded 1.1-fold difference in the gene expression is not high, it gives an indication that there was an induction of MT1 gene. The downregulated pattern of MT1 gene might be due to the overaccumulation of repressor apothionein protein which stops MT1 transcription. When the metal binds to the promoter region of the MT1 gene-repressor protein, it becomes inactive and increases the MT1 transcription, but at the same time accumulation of repressor protein downregulates MT1 gene. Our observations suggest that chronic Cd exposure elicits an elevated MT1 gene expression which in turn leads to detoxification. More elaborative study is warranted for further understanding of MT1 gene expression

Choosing the right cross-sectional imaging technique: Trading image quality for radiation risk

No abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83765/1/21536_ftp.pd

The Effectiveness of Educational Infographics in the Academic Achievement and Geological Sense Development among Tenth Grade Students in the Sultanate of Oman

This study aimed to  investigate the effectiveness of educational infographics in the academic achievement and the development of geological sense among tenth grade students in the Sultanate of Oman. To achieve the goals of the study, a sample of 452 female students from grade ten were chosen. They were divided into two groups. The effectiveness of infographics was measured by building an achievement test consisting of 25 single-type multiple choice items, and short essay questions. Likewise, a measure of geological sense was prepared, which consisted of 36 items distributed in 6 main categories: (the aesthetic sense, the scientific sense, the educational sense, the psychological sense, the national sense, and the economic sense). The validity of the two tools was verified by presenting them to 20 arbitrators. Their consistency was calculated using the internal consistency by the Cronbach alpha method, where the value of the stability coefficient in the test was 0.785, and the stability of the geological sense scale was 0.869. The results of the study indicated that there is a statistically significant difference between the female students’ scores in both the achievement and the geological sense scale for the benefit of the experimental group. In light of the results, the study recommended activating the use of infographics in the teaching of  geographical issues and spreading a culture of its use

Linear Parameter Varying Power Regulation of Variable Speed Pitch Manipulated Wind Turbine in the Full Load Regime

In a wind energy conversion system (WECS), changing the pitch angle of the wind turbine blades is a typical practice to regulate the electrical power generation in the full-load regime. Due to the turbulent nature of the wind and the large variations of the mean wind speed during the day, the rotary elements of the WECS are subjected to significant mechanical stresses and fatigue, resulting in conceivably mechanical failures and higher maintenance costs. Consequently, it is imperative to design a control system capable of handling continuous wind changes. In this work, Linear Parameter Varying (LPV) H_inf controller is used to cope with wind variations and turbulent winds with a turbulence intensity greater than 10%. The proposed controller is designed to regulate the rotational rotor speed and generator torque, thus, regulating the output power via pitch angle manipulations. In addition, a PI-Fuzzy control system is designed to be compared with the proposed control system. The closed-loop simulations of both controllers established the robustness and stability of the suggested LPV controller under large wind velocity variations, with minute power fluctuations compared to the PI-Fuzzy controller. The results show that in the presence of turbulent wind speed variations, the proposed LPV controller achieves improved transient and steady-state performance along with reduced mechanical loads in the above-rated wind speed region.Comment: 12 pages, 10 figure

Evaluation of Oxidative Stress and Antioxidant Status in Diabetic and Hypertensive Women during Labor

Pregnancy in insulin-dependent diabetes mellitus is associated with a greater incidence of fetal abnormality. Animal studies suggested that increased free-radical production and antioxidant depletion may contribute to this risk. The objective of this work was to evaluate oxidative stress and antioxidant capacity in hypertensive, diabetics, and healthy control women during labor. Simultaneous determination of antioxidant enzymes activities, namely glutathione peroxidase (GSH-Px), glutathione reductase (GSH-red), superoxide dismutase (SOD), total antioxidant, and lipid peroxides measured as thiobarbituric acid-reactive substances (TBARS) levels, were carried out in maternal plasma during labor. Plasma GSH-Px activity was found to be significantly increased as it doubled in hypertensive, and diabetic women when compared with healthy control women (P<0.05). In contrast, plasma SOD activity was significantly decreased in both groups when compared to the control group (P<0.05). No significant differences were detected in GSH-Red activity between diabetic, hypertensive and control groups. Alterations in antioxidant enzyme activities were accompanied by a significant increase in the levels of plasma lipid peroxides in hypertensive and diabetic women during labor. Plasma levels of total antioxidants were significantly increased in diabetic women as compared with the control group. Based on our results, it may be concluded that enhanced generation of oxidative stress causes alteration of antioxidant capacity in diabetic and hypertensive women during labor. Alterations in antioxidant and prooxidant components may result in various complications including peroxidation of vital body molecules which may be regarded as an increased risk factor for pregnant women as well as the fetus

General public knowledge, perceptions and practice towards pharmaceutical drug advertisements in the Western region of KSA

AbstractThis study aims to examine general public knowledge and behavior toward pharmaceutical advertisements in the Western part of KSA. A cross sectional convenience sampling technique was used in this study. A total of 1445 valid questionnaires were received and analyzed using SPSS version 16 at alpha value of 0.05. Majority of respondents were aware of different types of drugs to be advertised and drug advertisements should seek approval from the health authorities. Television and Internet showed the highest effect on consumers. Almost half of the participants preferred an advertised drug over non-advertised one. Most of the respondents indicated that the quality of frequently advertised drugs is not better than those prescribed by the doctors. Majority of participants had positive beliefs toward advertised drugs concerning their role in education and spreading of awareness among the public. Pharmaceutical advertisements harm the doctor–patient relationship as evidenced by one-third of the investigated sample. Moreover, majority of the participants mentioned that they would consult another doctor or even change the current doctor if he/she refused to prescribe an advertised medication. Results of this study could be used to develop awareness programs for the general public and try to enforce the regulations and policies to protect the general public and patients from the business oriented pharmaceutical companies and drug suppliers

Effectiveness of Phonological Awareness Skills Training in Improving Decoding Skills of Children with Reading Disabilities

The study aimed to investigate the effectiveness of a phonological awareness skills training program in improving decoding skills of third grade students with reading disabilities. The initial sample included 40 students enrolled in the learning disabilities program in elementary schools in Oman. They were assessed for diagnosing those who have reading disabilities through adopting the procedures of the IQ-achievement discrepancy model. The Raven’s Matrices and a reading achievement test were administered to students. Then, 14 students among those diagnosed with reading disabilities were randomly distributed to an experimental and a control group. Participants in the experimental group received training in phonological awareness for 10 weeks whereas the control group participants did not. The participants of both groups were administered two tests in phonological awareness (PA) and decoding skills (DS) pre and post the training. Results of the study indicated that there were statistically significant differences between the experimental and control groups on the sub-tests of the PA and DS tests except for fluency in reading passages. However, a comparison of the pre and post scores of the experimental groups showed that they obtained significant gains in all sub scores following the training

Exploring Sheraoh Island at South-Eastern Qatar: First Distributional Records of Some Inland and Offshore Biota with Annotated Checklist

Sheraoh island is the most remote among Qatari islands, nearly 73.5 km south-eastern of the mainland of the peninsula. In March 2010, a preliminary general survey of the species was conducted. Observations were made partly by wading and snorkeling in the intertidal zone and partly by surveying the inland habitats. In total the 31 species were recorded, 4 species of halophyte plants: Halopeplis perfoliata, Suaeda vermiculata, Salsola baryosoma and Zygophyllum qatarense, one unexpected terrestrial mammal: the cape hare Lepus capensis, 2 species of visiting birds: Motacilla flava and Anthus campestus and one species of sea bird. Phalacrocorax nigrogularis, one dolphin species: Sousa chinensis. The largest richness was found in the marine habitats, 3 species of sea weeds: Colpomenia sinusa, Padina boergesenii and Sargassum boveanum, 3 species of corals: Anomastraea irregularis, Platygyra lamellina and Porites harrisoni, 2 species of nudibranchs: Chromodoris cazae and Chromodoris sp. (unidentified)., 4 crab species: Hermit crab (unidentified), Etisus laevimanus, Grapsus albolineatus and Lambrus prensor, 4 species of echinoderms: Pentacentral mammillatus, Ophiothela venusta, Diadema setosum and Echinometra mathaei, 5 species of bony fish: Doryrhamphus sp. (larva), Cypserulus oligolepis, Lethrinus nebulosus, Cephalopholis miniatus and Hemiramphus marginatus, one species of sea snakes: Hydrophis sp. The most striking result is to collect an unknown nudibranch species and to report the cape hare which is unexpected inhabitant. All figures of this study are published for the first time in Qatar.Qatar Universit

Immunohistochemical Localization of Progesterone Receptors in the Non-pregnant One-humped Camel Uterus

The current study aimed to localize immunohistochemically the cellular progesterone receptors in the non-pregnant one-humped camel uterus. Uterine tissue specimens from 10 she-camels during estrous were collected from local slaughterhouses and prepared for indirect immunoperoxidase staining using primary antibody for human progesterone receptor PR (clone 10A9). Nuclear signals for progesterone receptors were clearly observed in the uterine surface epithelium, glandular epithelium, myometrium, uterine stroma and in walls of some large blood vessels. The staining intensity was variable at different uterine tissue regions. Strong signals were demonstrated in the superficial gland zone, in the connective tissue stroma and in the myometrium. However, Nuclear signals of moderate intensity were noticed in the surface epithelium, deep gland zones and in the walls of the uterine arteries. No cytoplasmic signals could be detected. The current study concluded that nuclear signals for progesterone receptors were found in uterine surface epithelium, uterine glands, myometrium, uterine blood vessels and stroma