25 research outputs found

    From PET Bottles Waste to N-Doped Graphene as Sustainable Electrocatalyst Support for Direct Liquid Fuel Cells

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    Direct liquid fuel cells represent one of the most rapidly emerging energy conversion devices. The main challenge in developing fuel cell devices is finding low-cost and highly active catalysts. In this work, PET bottle waste was transformed into nitrogen-doped graphene (NG) as valuable catalyst support. NG was prepared by a one-pot thermal decomposition process of mineral water waste bottles with urea at 800 °C. Then, NG/Pt electrocatalysts with Pt loadings as low as 0.9 wt.% and 1.8 wt.% were prepared via a simple reduction method in aqueous solution at room temperature. The physical and electrochemical properties of the NG/Pt electrocatalysts are characterized and evaluated for application in direct borohydride peroxide fuel cells (DBPFCs). The results show that NG/Pt catalysts display catalytic activity for borohydride oxidation reaction, particularly the NG/Pt_1, with a number of exchanged electrons of 2.7. Using NG/Pt composite in fuel cells is anticipated to lower prices and boost the usage of electrochemical energy devices. A DBPFC fuel cell using NG/Pt_1 catalyst (1.8 wt.% Pt) in the anode achieved a power density of 75 mW cm−2 at 45 °C. The exceptional performance and economic viability become even more evident when expressed as mass-specific power density, reaching a value as high as 15.8 W mgPt−1

    Understanding the influence of applying plant extracts and microorganism culture filtrates against barley leaf rust disease

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    Rust fungi are devastating plant pathogens, and several Puccinia species have exerting substantial financial impacts on global barley cultivation. Fungicides are used on a large scale as an effective method for combating phytopathogenic fungi. The negative environmental impacts of fungicides are steadily escalating on a daily basis. Consequently, researchers are currently exploring alternative approaches to mitigate the use of fungicides, such as the utilization of plant extracts. This method has proven effective due to its incorporation of natural antifungal substances. Among the nine natural elicitors that were tested, the application of plant extracts on barley seedlings resulted in an increase in the incubation and latent periods of Puccinia hordei. These periods are integral components of partial and induced resistance, effectively mitigating the incidence of barley leaf rust disease by over 70% on mature plants. Similarly, the biochemical analyses demonstrated a notable augmentation in all the tested treatments’ overall phenolics and oxidative enzyme activities (peroxidase and polyphenol oxidase). Random amplified polymorphic DNA (SCoT) test serves as a viable approach for assessing the impact of plant extracts and microorganisms on barley plants. The results obtained from this study indicate that the detection of DNA polymorphism through SCoT analysis holds a significant potential powerful tool to evaluate genetic changes compared with untreated plants although some of them tested displayed high similarities at the morphological reaction

    TRUST IN CROSS-CULTURAL B2B FINANCIAL SERVICE RELATIONSHIPS: THE ROLE OF SHARED VALUES

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    This is the accepted version of the following article: Houjeir, R. & Brennan, R. J, 'Trust in cross-cultural b2b financial service relationships: The role of shared values', Journal of Financial Services Marketing, June 2016, Vol 21(2): 90-102 The final publication is available at Springer via http://dx.doi.org/10.1057/fsm.2016.4Trust in business-to-business supplier–customer relationships in financial services is an area of considerable research interest. The bulk of prior empirical research in this field has concentrated on trust in business relationships within a Western cultural context. However, shared values are acknowledged to be an important antecedent to trust. The premise of this study is that in circumstances where there are substantial cultural differences between parties to a supplier–customer relationship, these differences will be reflected in shared values, which will in turn be reflected in differences in the nature of trust. A qualitative study was conducted among business bankers and their corporate clients in the context of the United Arab Emirates. In all 170 respondents were interviewed; of these, 160 were paired respondents, that is, where a client and banker from the same business relationship were interviewed (yielding 80 interview dyads). Substantial differences with respect to trust were found between relationships that involved only Emiratis, those that involved Emiratis and non-Emiratis, and those that involved only non-Emiratis. For Emiratis mutual trust is substantially based on family and clan ties and exhibits strongly affective characteristics. For non-Emiratis trust is largely based on business considerations, and exhibits strongly cognitive characteristics.Peer reviewedFinal Accepted Versio

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    The effect of adding long acting beta 2 agonists to inhaled corticosteroids versus increasing dose of inhaled corticosteroids in improving asthma control

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    To asthmatic patients with moderate to severe persistent asthma, two main treatment options are recommended: The combination of a long-acting inhaled ÎČ2-agonist with inhaled corticosteroids or the use of a higher dose of inhaled corticosteroids. The aim of this study was to evaluate which drug option is more favorable. Patients and methods: This study included 60 asthmatic patients uncontrolled on low doses of ICSs. They were randomized into two groups. Group (1): 30 patients received twice daily inhaled formetrol and budesonide in a dose of 12 mcg and 400 mcg, respectively. Group (2): 30 patients received two fold the previous dose of budesonide 800 mcg/BID alone. A comparative study was carried out at Outpatient Chest Clinic of Fayoum Hospital University for a period of 24 weeks using the spirometric data of patients of the two groups before and after treatment. Results: Results showed that the combination therapy of inhaled formetrol and budesonide is modestly more effective in the reduction of symptoms and in improving the lung functions than with a higher dose of budesonide alone. Conclusion: Adding formetrol in a dose of 12 Όg plus budesonide in a dose 400 Όg b.i.d. is more favorable in treatment of asthma than a higher dose of budesonide (800 Όg b.i.d)

    Shared Decision Making (SDM) in der GynÀkologie und Geburtshilfe: Landkarte der Beleglage

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    Effect of the Morphology of Tungsten Oxide Embedded in Sodium Alginate/Polyvinylpyrrolidone Composite Beads on the Photocatalytic Degradation of Methylene Blue Dye Solution

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    Tungsten oxide nanostructures were modified by oxygen vacancies through hydrothermal treatment. Both the crystalline structure and morphological appearance were completely changed. Spherical WO3·H2O was prepared from tungstic acid solution by aging at room temperature, while rod-like WO3·0.33H2O was prepared by hydrothermal treatment of tungstic acid solution at 120 °C. These structures embedded in sodium alginate (SA)/polyvinylpyrrolidone (PVP) were synthesized as novel porous beads by gelation method into calcium chloride solution. The performance of the prepared materials as photocatalysts is examined for methylene blue (MB) degradation in aqueous solutions. Different operation parameters affecting the dye degradation process, such as light intensity, illumination time, and photocatalyst dosage are investigated. Results revealed that the photocatalytic activity of novel nanocomposite changed with the change in WO3 morphology. Namely, the beads with rod nanostructure of WO3 have shown better effectiveness in MB removal than the beads containing WO3 in spherical form. The maximum degradation efficiency was found to be 98% for WO3 nanorods structure embedded beads, while the maximum removal of WO3 nanospheres structure embedded beads was 91%. The cycling-ability and reuse results recommend both prepared structures to be used as effective tools for treating MB dye-contaminated wastewaters. The results show that the novel SA/PVP/WO3 nanocomposite beads are eco-friendly nanocomposite materials that can be applied as photocatalysts for the degradation of cationic dyes in contaminated water

    Hashimoto thyroiditis is an independent cardiovascular risk factor in clinically hypothyroid patients

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    AbstractHypothyroidism is a common disorder that confers an increased cardiovascular risk. The most common cause is Hashimoto thyroiditis (HT) but it can also be caused by thyroidectomy and radioiodine therapy. The aim of the study is to examine whether there is a relation between the cause of hypothyroidism and cardiovascular risk.Subjects and methodsThe study included 20 patients with Hashimoto thyroiditis and hypothyroidism, 20 patients with post-thyroidectomy hypothyroidism, 20 patients with post-radioiodine hypothyroidism, and 20 age and sex matched controls. In all the studied subjects we determined thyroid function tests; TSH and F.T4, thyroid auto-antibodies; anti-TPO and anti-TG antibodies, carotid intima media thickness (CIMT), flow mediated dilation (FMD) and serum nitric oxide.ResultsCIMT showed a trend to be higher in HT group (0.93±0.08mm) compared to other causes of hypothyroidism (P=0.090). Multivariate analysis showed that HT is an independent predictor of CIMT (P=0.015). FMD was significantly lower in HT group (5.74±1.33%) compared to post-thyroidectomy (7.16±1.05%) (P=0.001), and post-radioiodine therapy (7.34±1.34%) (P=0.000). Multivariate analysis showed that HT is an independent predictor of FMD (P=0.000). NO was significantly higher in hypothyroid patients (125.98±5.03ΌM/ml) compared to controls (39.44±3.63ΌM/ml) (P=0.001), both univariate and multivariate analyses showed that NO is an independent predictor of both CIMT and FMD (P=0.000).ConclusionTo our knowledge, this is the first study to show that Hashimoto thyroiditis is an independent cardiovascular risk factor in clinically hypothyroid patients

    Sustainable Microbial and Heavy Metal Reduction in Water Purification Systems Based on PVA/IC Nanofiber Membrane Doped with PANI/GO

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    Effective and efficient removal of both heavy metal pollutants and bacterial contamination from fresh water is an open issue, especially in developing countries. In this work, a novel eco-friendly functional composite for water treatment application was investigated. The composite consisted of electrospun nanofiber membrane from blended polyvinyl alcohol (PVA)/iota carrageenan (IC) polymers doped with equal concentrations of graphene oxide (GO) nanoparticles and polyaniline (PANI). The effectiveness of this composite as a water purification fixed-bed filter was optimized in a batch system for the removal of cadmium (Cd+2) and lead (Pb+2) ions, and additionally characterized for its antimicrobial and antifungal properties and cytotoxicity effect. The fiber nanocomposite exhibited efficient antibacterial activity, with maximum adsorption capacity of about 459 mg g-1 after 120 min for Cd+2 and of about 486 mg g-1 after 90 min for Pb+2. The optimized conditions for removal of both metals were assessed by using a response surface methodology model. The resulting scores at 25 °C were 91.4% (Cd+2) removal at 117 min contact time for 89.5 mg L-1 of initial concentration and 29.6 cm2 membrane area, and 97.19% (Pb+2) removal at contact time 105 min for 83.2 mg L-1 of initial concentration and 30.9 cm2 nanofiber composite membrane. Adsorption kinetics and isotherm followed a pseudo-second-order model and Langmuir and Freundlich isotherm model, respectively. The prepared membrane appears to be promising for possible use in domestic water purification systems
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