904 research outputs found
Review on the science and technology of water desalination by capacitive deionization
Porous carbon electrodes have significant potential for energy-efficient water desalination using a promising technology called Capacitive Deionization (CDI). In CDI, salt ions are removed from brackish water upon applying an electrical voltage difference between two porous electrodes, in which the ions will be temporarily immobilized. These electrodes are made of porous carbons optimized for salt storage capacity and ion and electron transport. We review the science and technology of CDI and describe the range of possible electrode materials and the various approaches to the testing of materials and devices. We summarize the range of options for CDI-designs and possible operational modes, and describe the various theoreticalâconceptual approaches to understand the phenomenon of CDI
Efficient oxidative dearomatisations of substituted phenols using hypervalent iodine (iii) reagents and antiprotozoal evaluation of the resulting cyclohexadienones against T. b. rhodesiense and P. falciparum Strain NF54
Quinones and quinols are secondary metabolites of higher plants that are associated with many biological activities. The oxidative dearomatization of phenols induced by hypervalent iodine(III) reagents has proven to be a very useful synthetic approach for the preparation of these compounds, which are also widely used in organic synthesis and medicinal chemistry. Starting from several substituted phenols and naphthols, a series of cyclohexadienone and naphthoquinone derivatives were synthesized using different hypervalent iodine(III) reagents and evaluated for their in vitro antiprotozoal activity. Antiprotozoal activity was assessed against Plasmodium falciparum NF54 and Trypanosoma brucei rhodesiense STIB900. Cytotoxicity of all compounds towards L6 cells was evaluated and the respective selectivity indices (SI) were calculated. We found that benzyl naphthoquinone 5c was the most active and selective molecule against T. brucei rhodesiense (IC50 = 0.08 muM, SI = 275). Furthermore, the antiprotozoal assays revealed no specific effects. In addition, some key physicochemical parameters of the synthesised compounds were calculated
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Author Correction: Persistent and reversible solid iodine electrodeposition in nanoporous carbons
Correction to: Nature Communications https://doi.org/10.1038/s41467-020-18610-6, published online 24 September 2020
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Work relations and the multiple dimensions of the work-life boundary: Hairstyling at home
This article proposes a multidimensional approach to analysis of the work-life boundary and examines the affects of particular social and organizational relations on the preservation or porous-ness of different dimensions. In line with Nippert-Eng (1996), it is suggested that different dimensions of the boundary are reinforced or weakened by different social and organizational pressures. Analysis describes a specific type of multidimensional breaching â instances when work is taken outside of the worksite (spatial breaching) and is carried out outside of work-time (temporal breaching). Empirical research was conducted among hairstylists working in salons and barbershops in a city in the North of England. Because of the nature of the tasks involved in hairstyling â that the skills involved are widely exchangeable and so may be employed in extra-work environments and temporalities â hairstylists provide a nice site for investigating the circumstances when this does (or does not) occur. Data collection involved a comprehensive self-completion survey of salons and barbershops in the city (response rate: 40%; N=132) and semi-structured interviews with 70 stylists working in 52 salons or barbershops. Findings demonstrate that work relations (hairstylistsâ structural relations of production â whether a worker is an owner-proprietor, chair-renter, on-commission stylist, basic-only stylist, or trainee) are critical in determining both workersâ ability and desire to resist the seepage of work into their social lives as well as the particular dimensions of the boundary that are breached. This is because work relations affect the relative importance of four identified motivations for taking work out of the salon (income production; training; inter-personal reciprocity rooted in social relations; and inter-personal reciprocity rooted in the workplace)
Fabrication of bismuth nanowires with a silver nanocrystal shadowmask
We fabricated bismuth (Bi) nanowires with low energy electron beam lithography using silver (Ag) nanocrystal shadowmasks and a subsequent chlorine reactive ion etching. Submicron-size metal contacts on the single Bi nanowire were successfully prepared by in situ focused ion beam metal deposition for transport measurements. The temperature dependent resistance measurements on the 50 nm wide Bi nanowires showed that the resistance increased with decreasing temperature, which is characteristic of semiconductors and insulators
Palladium-catalysed synthesis of arylnaphthoquinones as antiprotozoal and antimycobacterial agents
Malaria and tuberculosis are still among the leading causes of death in low-income countries. The 1,4-naphthoquinone (NQ) scaffold can be found in a variety of anti-infective agents. Herein, we report an optimised, high yield process for the preparation of various 2-arylnaphthoquinones by a palladium-catalysed Suzuki reaction. All synthesised compounds were evaluated for their in-vitro antiprotozoal and antimycobacterial activity. Antiprotozoal activity was assessed against Plasmodium falciparum (P.f.) NF54 and Trypanosoma brucei rhodesiense (T.b.r.) STIB900, and antimycobacterial activity against Mycobacterium smegmatis (M.s.) mc(2) 155. Substitution with pyridine and pyrimidine rings significantly increased antiplasmodial potency of our compounds. The 2-aryl-NQs exhibited trypanocidal activity in the nM range with a very favourable selectivity profile. (Pseudo)halogenated aryl-NQs were found to have a pronounced effect indicating inhibition of mycobacterial efflux pumps. Cytotoxicity of all compounds towards L6 cells was evaluated and the respective selectivity indices (SI) were calculated. In addition, the physicochemical parameters of the synthesised compounds were discussed
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Hydrogel-Based Flexible Energy Storage Using Electrodes Based on Polypyrrole and Carbon Threads
Developing new flexible and electroactive materials is a significant challenge to producing safe, reliable, and environmentally friendly energy storage devices. This study introduces a promising electrolyte system that fulfills these requirements. First, polypyrrole (PPy) nanotubes are electropolymerized in graphite-thread electrodes using methyl orange (MO) templates in an acidic medium. The modification increases the conductivity and does not compromise the flexibility of the electrodes. Next, flexible supercapacitors are built using hydrogel prepared from poly(vinyl alcohol) (PVA)/sodium alginate (SA) obtained by freezeâthawing and swollen with ionic solutions as an electrolyte. The material exhibits a homogenous and porous hydrogel matrix allowing a high conductivity of 3.6 mS cmâ1 as-prepared while displaying great versatility, changing its electrochemical and mechanical properties depending on the swollen electrolyte. Therefore, it allows its combination with modified graphite-thread electrodes into a quasi-solid electrochemical energy storage device, achieving a specific capacitance (Cs) value of 66 F gâ1 at 0.5 A gâ1. Finally, the flexible device exhibits specific energy and power values of 19.9 W kgâ1 and 3.0 Wh kgâ1, relying on the liquid phase in the hydrogel matrix produced from biodegradable polymers. This study shows an environment friendly, flexible, and tunable quasi-solid electrolyte, depending on a simple swell experiment to shape its properties according to its application
The evolutionary dynamics of the Saccharomyces cerevisiae protein interaction network after duplication
Gene duplication is an important mechanism in the evolution of protein interaction networks. Duplications are followed by the gain and loss of interactions, rewiring the network at some unknown rate. Because rewiring is likely to change the distribution of network motifs within the duplicated interaction set, it should be possible to study network rewiring by tracking the evolution of these motifs. We have developed a mathematical framework that, together with duplication data from comparative genomic and proteomic studies, allows us to infer the connectivity of the preduplication network and the changes in connectivity over time. We focused on the whole-genome duplication (WGD) event in Saccharomyces cerevisiae. The model allowed us to predict the frequency of intergene interaction before WGD and the post duplication probabilities of interaction gain and loss. We find that the predicted frequency of self-interactions in the preduplication network is significantly higher than that observed in today's network. This could suggest a structural difference between the modern and ancestral networks, preferential addition or retention of interactions between ohnologs, or selective pressure to preserve duplicates of self-interacting proteins
Anisometric Charge Dependent Swelling of Porous Carbon in an Ionic Liquid
In situ electrochemical dilatometry was used to study, for the first time,
the expansion behavior of a porous carbon electrode in a pure ionic liquid,
1-ethyl-3-methyl-imidazolium-tetrafluoroborate. For a single electrode, an
applied potential of -2 V and +2 V against the potential of zero charge
resulted in maximum strain of 1.8 % and 0.5 %, respectively. During cyclic
voltammetry, the characteristic expansion behavior strongly depends on the scan
rate, with increased scan rates leading to a decrease of the expansion.
Chronoamperometry was used to determine the equilibrium specific capacitance
and expansion. The obtained strain versus accumulated charge relationship can
be fitted with a simple quadratic function. Cathodic and anodic expansion data
collapses on one parabola when normalizing the surface charge by the ratio of
ion volume and average pore size. There is also a transient spike in the height
change when polarity is switched from positive to negative that is not observed
when changing the potential from negative to positive indicating the size and
the shape of the ion is influencing the expansion behavior.Comment: 10 pages double spaced, 3 figs, Electrochemistry Communications,
accepte
Religious faith and psychosocial adaptation among stroke patients in Kuwait: A mixed method study
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Springer Science+Business Media.Religious faith is central to life for Muslim patients in Kuwait, so it may influence adaptation and rehabilitation. This study explored quantitative associations among religious faith, self-efficacy, and life satisfaction in 40 female stroke patients and explored the influence of religion within stroke rehabilitation through qualitative interviews with 12 health professionals. The quantitative measure of religious faith did not relate to life satisfaction or self-efficacy in stroke patients. However, the health professionals described religious coping as influencing adaptation post-stroke. Fatalistic beliefs were thought to have mixed influences on rehabilitation. Measuring religious faith among Muslims through a standardized scale is debated. The qualitative accounts suggest that religious beliefs need to be acknowledged in stroke rehabilitation in Kuwait
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