Investigating critical thinking skills practices in Qatari Elementary Schools

The purpose of this study was to examine how government and independent elementary school teachers in Qatar compare on promoting students' critical thinking skills in the classroom. A total of 441 participants completed a 30-item, critical thinking skills questionnaire based on Bloom's taxonomy of educational objectives - cognitive domain, which aimed at assessing teachers' frequency of using certain critical thinking activities in the context of classroom instruction. Multivariate analysis of variance procedure indicated significant differences on the application, analysis, synthesis, and evaluation levels, but not on knowledge and comprehension. No significant differences were observed between the government and independent school teachers based on years of teaching experience. These results are discussed in light of their implications for the undergoing education reform in Qatar

Heparan sulfate-protein interactions : evidence for sulfate group-dependent selectivity

Heparan sulfates (HS) are a family of structurally diverse, sulfated polysaccharides located at the cell surface and in the extracellular matrix. They are distributed widely in virtually all metazoan organisms. The structural diversity occurs via variability in the positions of sulfation along the HS chain and in (l L-iduronic acid and D› glucuronic acid substitutions. There is now strong evidence that these molecules perform diverse functions in vivo through their ability to regulate the activity of different proteins. A wide variety of proteins have been found to be ligands for liS, including growth factors, cytokines, receptors, adhesion and matrix molecules, enzymes, coagulation factors and a variety of bacterial and viral coat proteins. Hence, there is a very significant need to determine the molecular basis of HS activity and HS-protein interactions, addressing important issues such as the degree of molecular selectivity. In this study, two model protein systems were selected to test the hypothesis that selective saccharide sequence and sulfation patterns regulate protein binding and activity. In the first model, heparin and chemically modified heparin saccharides were screened for Slit and Robo binding and activity, as signalling by Slit requires two receptors, Robo transmembrane proteins and HS. How liS controls Slit-Robo signalling is unclear. Competition and direct enzyme linked immunoassay (ELISA) data showed that heparin derivatives enhance the affinity of Slit-Robo binary and ternary complexes. Analytical gel filtration chromatography demonstrated that Slit associates with a soluble Robo fragment and heparin derivatives to form a ternary complex. Furthermore, retinal growth cone collapse triggered by Slit requires cell surface HS or exogenously added heparin derivatives. The data indicate a complex relationship between HS binding and Slit-Robo proteins, which support selectivity in regulation of signalling responses, but do not suggest requirement for strictly defined sequence. In the second model, HS saccharides were prepared by heparinase treatment of porcine mucosal HS and purified by size-exclusion and SAX-IIPLC chromatography. Purified or semi-purified complex sulfated HS 6-mer and 8-mer sequences were prepared. This library was screened for binding to FGF-l and FGF-2 using a competition ELISA, and for corresponding bioactivity (regulation of FGF-l and FGF-2 signalling using a BaF3 cell assay with defined FGF receptors). This screen identified fractions that bound and activated these ligands, and ones that did not. Selected structures were subjected to activity analysis after further separation using ion-pairing reverse phase (IPRP-HPLC). Structures with similar or identical size and sulfation content, but distinct sulfation sequences, differed widely in their bioactivity, though binding data alone did not necessarily predict activity. The results provided information that supports the view that a significant degree of specificity for activation of FGF biological activity is encoded in the complex sulfation sequences observed in lIS chains. However, is not simply related to sulfation pattern. Over~ll: the results from these two model protein systems suggest that the degree of selectiVIty or specificity of HS structures for regulation of biological activity is complex, and varies according to the proteins involved. Nevertheless, they provide the basis for lIS to act as an important modulator of protein function in a wide variety of biological systems

Analysis of product distribution and characteristics of bio-oil and bio-char from fast pyrolysis of date palm tree waste

According to recent reports, there are more than 120 million date palm trees worldwide, with the estimated Middle East and North Africa combined share of more than 80%. Date palm trees produce huge amounts of waste amounting to 15-35 kg per tree per year. This represents a challenging environmental problem, since disposal is so far mainly based on landfill and uncontrolled combustion. Please click on the file below for full content of the abstract

Study of the Rheological Behavior of Polyamide 5,6 (PA5,6

The rheological behavior of polymer melts and polymer solutions are of great importance in polymer processing, particularly for the analysis and design of processing operations as well as understanding the relationship between structures and properties of the final-products. The objective of the present work was to investigate the rheological behavior of polyamide 5,6  (PA5,6) to obtain information on the effect of temperature on the melt behavior of polyamide 5,6 compared to that of polyamide 6. The rheological properties of polyamide 5,6 (PA5,6) have been studied by means of a Haake  rheometer. The effect of temperature on the storage modulus, loss modulus, and complex viscosity was studied. The obtained results showed that the complex viscosity, storage modulus, and loss modulus of PA5,6 and PA6 decrease with increase of the temperature. It is worth noting that the complex viscosity of PA5,6 remains almost constant showing a Newtonian behavior, on the other hand, the complex viscosity of PA6 slightly decreases with the increase of shear rate exhibits a much nearly Newtonian behavior. Similar behavior was observed for other polyamides such as polyamide 6.6 and polyamide 6.,1

Lawsonia inermis seeds cotyledon and coat extracts as a potential antimicrobial agent

Background: The plant Lawsonia inermis, which is a member of the Lythraceae family, has long been used to cure a number of diseases. Previous studies have demonstrated the antibacterial capabilities of the plant's components. However, neither the efficiency of these extracts on bacterial strains that are antibiotic-resistant nor a systematic analysis of the extracts from the various seed components have been conducted. Methods: The coat part was separated from the cotyledon. Each part was pulverized and extracted with ethanol, acetone, and hexane. The inhibitory effects of the resulting extracts were tested on three pathogenic bacterial strains and a fungus. The effect of the extracts on antibiotic-resistant bacteria was also evaluated.Results: When tested against pathogenic bacteria (Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumonia, and Candida albicans), L. inermis seed parts (cotyledon and coat) showed varying levels of antibacterial and antifungal activity. In which the ethanolic extract outperformed the acetonic extract in effectiveness. The minimal inhibitory concentration (MIC) for each pathogenic microorganism was established. Utilizing the extract yield, total antibacterial activity (TAA) was calculated. Lawsonia inermis seed components inhibited antibiotic-resistant strains of S. aureus and P. aeruginosa, with strong antibacterial activity seen in aqueous extracts of their cotyledons and coats.Conclusion: We summarize that Lawsonia inermis seed extracts, which have historically been used as secure antimicrobials for human healthcare and cosmetics have the potential to replace current antimicrobial agents that are no longer effective. Moreover, may be a promising source for the isolation of potent drugs for the treatment of bacterial diseases.Keywords: Lawsonia inermis; Henna; Extract; Seeds; Bacterial Infection; Antibiotics Resistance   

An Algebraic Hyperbolic Spline Quasi-Interpolation Scheme for Solving Burgers-Fisher Equations

In this work, the results on hyperbolic spline quasi-interpolation are recalled to establish the numerical scheme to obtain approximate solutions of the generalized Burgers-Fisher equation. After introducing the generalized Burgers-Fisher equation and the algebraic hyperbolic spline quasi-interpolation, the numerical scheme is presented. The stability of our scheme is well established and discussed. To verify the accuracy and reliability of the method presented in this work, we select two examples to conduct numerical experiments and compare them with the calculated results in the literature

Detection of Trypanozoon trypanosomes infections on Glossina fuscipes fuscipes (Diptera: Glossinidae) using polymerase chain reaction (PCR) technique in the Blue Nile State, Sudan

Tsetse flies transmit many species of trypanosomes in Africa, some of which are human and livestock pathogens of major medical and socio-economic impact. Identification of trypanosomes is essential to assess the disease risk imposed by particular tsetse populations. The present study was carried out to determine the trypanosomal infection rate of tsetse flies (Glossina fuscipes fuscipes) in the Blue Nile State of Sudan. A polymerase chain reaction (PCR) assay was used because of the inherent difficulty of speciating trypanosomal parasites in the fly. Our results show that 4.44% (8/180) of the flies were positive for a Trypanosoma brucei group. Three of eight positive flies reacted with primers for Trypanosoma b. rhodesiense. We did not detect flies infected with T. b. gambiense. Thus, the burden of flies harboring T. b. rhodesiense and T. b. brucei trypanosomes were 1.67 and 2.78%, respectively. This is the first evidence of T. b. rhodesiense in the Yabus District. Thus, HAT case-detection active surveillance and tsetse fly control campaigns should be conducted before the establishment of human settlement, investment of natural resources into agricultural and animal husbandry.Key words: Glossina fuscipes fuscipes, Trypanosoma brucei, T. b. gambiense, T. b. rhodesiense, infection rate, PCR technique, Blue Nile State