1,209 research outputs found

    Mr. Presidential Candidate: Whom Would You Nominate?

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    Presidential candidates compete on multiple fronts for votes. Who is more likeable? Who will negotiate more effectively with allies and adversaries? Who has the better vice-presidential running mate? Who will make better appointments to the Supreme Court and the cabinet? This last question is often discussed long before the inauguration, for the impact of a secretary of state or a Supreme Court justice can be tremendous. Despite the importance of such appointments, we do not expect candidates to compete on naming the better slates of nominees. For the candidates themselves, avoiding competition over nominees in the pre-election context has personal benefits—in particular, enabling them to keep a variety of supporters working hard on the campaign in the hope of being chosen as nominees. But from a social perspective, this norm has costs. This Article proposes that candidates be induced out of the status quo. In the current era of candidates responding to internet queries and members of the public asking questions via YouTube, it is plausible that the question—“Whom would you nominate (as secretary of state or for the Supreme Court)?”—might be asked in a public setting. If one candidate is behind in the race, he can be pushed to answer the question—and perhaps increase his chances of winning the election

    Luminescent, sorptive and antibacterial potential of bismuth-organic framework

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    Metal organic frameworks are formed by the three-dimensional linkage of metal cores and organic linkers. In this work, bismuth-based metal organic framework (Bi-MOF) has been synthesized by using 5-hydroxyisophthalic acid (H2HIA) as linker via hydrothermal method. The said MOF was structurally characterized by UV/Vis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), 1H NMR, energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA) and X-ray diffraction technique. This MOF showed highly porous structure with surface area 1096 m2/g as determined by BET analysis. A model batch adsorption experiment was performed to evaluate the efficiency of methylene blue (MB) dye removal from aqueous media. It was found that monolayer adsorption capacity calculated from the Langmuir isotherm was 0.6240 mg/g. Bi-MOF was also screened for its antibacterial and luminescent behavior.                     KEY WORDS: Bismuth, Metal-organic Frameworks, Luminescence, Sorption   Bull. Chem. Soc. Ethiop. 2021, 35(1), 119-128. DOI: https://dx.doi.org/10.4314/bcse.v35i1.1

    Antibacterial activity studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with Mannich base ligand

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    ABSTRACT. A Mannich base ligand (L) was prepared by reacting 2-mercaptobenzimidazole, diphenylamine and benzaldehyde. This ligand (L) was further used for the preparation of four metal complexes with Co(II), Ni(II), Cu(II) and Zn(II) ions. The reactions were monitored by TLC. The synthesized compounds were structurally characterized using FTIR spectroscopy, UV-Visible spectroscopy, 1H- and 13C-NMR spectroscopy, ICP-OES/atomic absorption spectroscopy. It has been observed that the ligand (L) behaved in a monoanionic bidentate mode and the geometry of resulting complexes was tetrahedral. Conductivity analysis revealed their non-electrolytic nature. Antibacterial activity of the synthesized compounds was assessed through an agar well diffusion method against four strains of Gram-negative bacteria. L-Zn(II) complex showed best activity at all four concentrations against the four strains of Gram-negative bacteria.               KEY WORDS: Metal complexes, Mannich bases, 2-Mercaptobenzimidazole, Antibacterial activity Bull. Chem. Soc. Ethiop. 2019, 33(3), 485-492.DOI: https://dx.doi.org/10.4314/bcse.v33i3.

    Synthesis, structural and photo-physical studies of transition metal complexes with Mannich bases derived from 2-mercaptobenzimidazole

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    Two Mannich base ligands, [1-(di-n-butylamine-N-methyl)mercapto-1H-benz-imidazole] (L1) and [1-(diphenylamine-N-methyl)mercapto-1H-benzimidazole] (L2)have been synthesized and further reacted with Co(II), Ni(II), Cu(II) and Zn(II) ionsto afford their respective complexes. The progress of the reaction was monitored by thin layer chromatography. The structural elucidation of Mannich base ligands and their metal complexes was done by Fourier Transform Infrared (FTIR), UV-Visible, Nuclear Magnetic Resonance spectroscopy (1H NMR & 13C NMR) and Atomic absorption spectroscopy (AAS) / Inductively coupled plasma emission spectroscopy (ICPES). FTIR and NMR studies supported the monoanionic bidentate coordination mode of L1 and L2 while tetrahedral geometries of metal complexes were proposed on the basis of AAS/ICP, magnetic moment and electronic spectroscopic data. The synthesized compounds were also investigated for their luminescent behavior which exhibited broad emission bands indicating charge transfer nature of the involved transitions.               KEY WORDS: Metal complexes, Mannich bases, 2-Mercaptobenzimidazole, Luminescence Bull. Chem. Soc. Ethiop. 2018, 32(3), 481-490.DOI: https://dx.doi.org/10.4314/bcse.v32i3.

    Atmospheric pressure plasma and depositions of antibacterial coatings

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    Healthcare-associated infections (HCAI) are complications of healthcare that result in elevated patient morbidity and mortality. HCAI present a huge financial burden for patients, hospitals and insurers due to extended hospitalisation and associated care. According to the estimations, in the US alone, HCAI affects approximately 2 million patients annually, of whom approximately 90.000 patients die, with an estimated annual cost estimated to range from 28 billion to 45 billion US$. [1] European Union is facing the similar situation, the European Centre for Disease Prevention and control (ECDC) advice that approximately 4.1 million acute care patients acquire a HCAI annually, with 37.000 deaths directly attributed to HCAI. With increasing prevalence of HCAI across European countries and threatening development of antimicrobial resistance to widely used antibiotics, there is a recognised need for novel approach in battle against this healthcare burden [2]. One of the approaches involves a development and fabrication of materials with antimicrobial properties. Usually, these are coatings with integrated antibacterial agent that is responsible for the elimination of microorganisms that come into contact with active surface. There is a variety of different antibacterial compounds integrated in such coatings, such as different antibiotics, chemical compounds, peptides. Recently, metal nanoparticles (NPs) have been increasingly used in designing coatings with antibacterial properties due to their large surface-to-volume ration, physiochemical properties and biological multi-target mechanism of actions. Besides all beneficial properties of NPs their emergence of cytotoxicity is limiting their practical applications in human body. [3-4] To overcome this drawback it is important to design a new class of antibacterial coatings with firmly embedded NPs that allows controlled release of antimicrobial agent into the microenvironment. Atmospheric pressure plasma technology has shown a big promise as an alternative and cost-efficient method for deposition of coatings with antibacterial properties. This contribution explores the potential of plasma-assisted approach for fabrication of antibacterial coatings, containing different metal NPs on medical textiles. Plasma-assisted deposition of coatings was carried out with so-called ˝sandwich technique˝, where nanoparticles were embedded between two layers in order to tailor the desirable ion release and to prolong antibacterial effect of fabrics. Antibacterial effects of different nano-coatings were tested against G+ and G- bacterial species, Staphylococcus aureus and Escherichia coli, respectively. Besides antibacterial properties, potential cytotoxic effects were also studied. The study demonstrates that atmospheric pressure plasma can be an efficient technique for deposition of antibacterial coatings containing metal NPs. Medical textiles with plasma-assisted nano-coatings showed effective antibacterial properties. The choice of proper metal antimicrobial agent and optimal concentration of NPs should be considered in regards to potential cytotoxic effects when these materials would be used in medical environments.info:eu-repo/semantics/publishedVersio

    Antibacterial nanocomposites based on Ag NPs and HMDSO deposited by atmospheric pressure plasma

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    The development of new multifunctional coatings with antimicrobial properties has a special interest in several applications for pharmaceutical and medical products. This work reports on the deposition of antimicrobial coatings based on silver nanoparticles (Ag NPs) embedded in an organosilicon film onto woven and nonwoven textiles. The Ag nanoparticles admixed with hexamethyldisiloxane (HMDSO) vapours are introduced by means of an atomizer system in the remote discharge of an atmospheric pressure plasma source operating in argon. The chemical properties and the surface morphology of the coatings with antimicrobial potential are discussed.This work was performed within the M-ERA-NET project PlasmaTex, contract 31/2016/ UEFISCDI. The financial support from the Ministry of Research and Innovation under the Nucleus contract 4N/2016 is gratefully acknowledged.info:eu-repo/semantics/publishedVersio

    Atmospheric-pressure plasma spray deposition of silver/HMDSO nanocomposite on polyamide 6,6 with controllable antibacterial activity

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    "Paper presented at the ICON2019 conferences in Çorlu, Tekirdağ, Turkey April 17-19, 2019"Novel coatings containing silver nanoparticles (AgNPs) with strong bonding and controllable antibacterial activity on polyamide 6,6 fabric were produced by dielectric barrier discharge (DBD) plasmaassisted deposition at atmospheric pressure and hexamethyldisiloxane (HMDSO) layers. Silver ion release was tuned using a “sandwich” coating structure to prolong the antibacterial effect. The novel spray-assisted deposition increased deposition rates of AgNPs using atmospheric pressure DBD plasma treatment when an HMDSO layer was applied. An increase in AgNPs deposition in plasma treated samples and antimicrobial activity against Gram-negative (Escherichia coli) for samples with an additional HMDSO layer was observed. These coatings allow the development of new and safe wound dressings able to switch the antimicrobial effect against Gram- positive and Gram-negative bacteria by washing the dressing at high temperature (75 oC) before application.This work was funded by European Regional Development funds (FEDER) through the Competitiveness and Internationalization Operational Program (POCI) – COMPETE and by National Funds through Portuguese Fundação para a Ciência e Tecnologia (FCT) under the project UID/ CTM/00264/2019. Ana Ribeiro acknowledges FCT for its doctoral grant SFRH/BD/137668/2018. Andrea Zille also acknowledges fnancial support of the FCT through an Investigator FCT Research contract (IF/00071/2015) and the project PTDC/CTM-TEX/28295/2017 fnanced by FCT, FEDER, and POCI in the frame of the Portugal 2020 program

    DBD plasma treatment and chitosan layers - A green method for stabilization of silver nanoparticles on polyamide 6.6

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    The addition of silver nanoparticles (AgNPs) to biomedical textiles can be of great interest to protect the materials against microorganisms and prevent their spread. However, the human and environmental over‐exposure to AgNPs is leading to numerous concerns due to their toxicity. In this work, AgNPs were stabilized onto polyamide 6.6 fabrics (PA66) through atmospheric dielectric barrier discharge (DBD) plasma treatment and the use of chitosan (Ch) layers applied by spray. DBD plasma treatment revealed a crucial role in AgNPs adhesion (4.8 and 6.3 At%). A first layer of Ch decreased the AgNPs adhesion in both untreated and DBD plasma‐treated samples but treated samples show higher concentration (1.7 and 4.1 At%). The antibacterial activity was evaluated against Staphylococcus aureus and Escherichia coli after 2 and 24 h, showing a superior action in all samples with DBD plasma treatment after 24 h. The Ch in the first layers of the composites delayed the antimicrobial action of the samples but it also may enhance antimicrobial action. The obtained coatings will allow the development of novel and safe wound dressings with improved AgNPs deposition, controlled ions released and consequently, manage the antimicrobial performance and minimize the AgNPs side effects

    Sociodemographic, Attitudinal, and Behavioral Correlates of Using Nutrition, Weight Loss, and Fitness Websites : An Online Survey

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    Background: Nutrition, diet, and fitness are among the most searched health topics by internet users. Besides that, health-related internet users are diverse in their motivations and individual characteristics. However, little is known about the individual characteristics associated with the usage of nutrition, weight loss, and fitness websites. Objective: The aim of this study was to examine the individual factors associated with the usage of nutrition, weight loss, and fitness websites. Methods: An invitation to an online survey was published on 65 websites and discussion forums. In total, we employed data from 623 participants (aged 13 to 39 years, mean 24.11 [SD 5.26]). The measures included frequency of usage of nutrition, weight loss and fitness websites, excessive exercise, eating disorder symptomatology, internalization of the beauty ideal, weight status, and perceived online social support. Participants’ data were used as predictors in a base linear regression model. Results: The final model had an acceptable fit (X210 =14.1; P=.17; root mean square error of approximation=0.03; comparative fit index=0.99; Tucker-Lewis index=0.99). Positive associations were found between usage of (1) nutrition websites and being female, higher levels of excessive exercise, and perceived online social support; (2) weight loss websites and excessive exercise, internalization, being female, eating disorder symptomatology, and being overweight or obese; and (3) fitness websites and levels of excessive exercise, internalization, and frequency of internet use. Conclusions: The results highlighted the importance of individual differences in the usage of health-related websites
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