Li+ Insertion in Nanostructured TiO2 for Energy Storage

Nanostructured materials possess unique physical-chemical characteristics and have attracted much attention, among others, in the field of energy conversion and storage devices, for the possibility to exploit both their bulk and surface properties, enabling enhanced electron and ion transport, fast diffusion of electrolytes, and consequently high efficiency in the electrochemical processes. In particular, titanium dioxide received great attention, both in the form of amorphous or crystalline material for these applications, due to the large variety of nanostructures in which it can be obtained. In this paper, a comparison of the performance of titanium dioxide prepared through the oxidation of Ti foils in hydrogen peroxide is reported. In particular, two thermal treatments have been compared. One, at 150 °C in Ar, which serves to remove the residual hydrogen peroxide, and the second, at 450 °C in air. The material, after the treatment at 150 °C, results to be not stoichiometric and amorphous, while the treatment at 450 °C provide TiO2 in the anatase form. It turns out that not-stoichiometric TiO2 results to be a highly stable material, being a promising candidate for applications as high power Li-ion batteries, while the anatase TiO2 shows lower cyclability, but it is still promising for energy-storage devices

Monensin Improves the Effectiveness of meso-Dimercaptosuccinate when Used to Treat Lead Intoxication in Rats

Among divalent cations, the ionophore monensin shows high activity and selectivity for the transport of lead ions (Pb(2+)) across phospholipid membranes. When coadministered to rats that were receiving meso-dimercaptosuccinate for treatment of Pb intoxication, monensin significantly increased the amount of Pb removed from femur, brain, and heart. It showed a tendency to increase Pb removal from liver and kidney but had no effect of this type in skeletal muscle. Tissue levels of several physiologic (calcium, cobalt, copper, iron, magnesium, manganese, molybdenum, zinc) and nonphysiologic (arsenic, cadmium, chromium, nickel, strontium) elements were also determined after the application of these compounds. Among the physiologic elements, a number of significant changes were seen, including both rising and falling values. The size of these changes was typically around 20% compared with control values, with the largest examples seen in femur. These changes often tended to reverse those of similar size that had occurred during Pb administration. Among the nonphysiologic elements, which were present in trace amounts, the changes were smaller in number but larger in size. None of these changes appears likely to be significant in terms of toxicity, and there were no signs of overt toxicity under any of the conditions employed. Monensin may act by cotransporting Pb(2+) and OH(–) ions out of cells, in exchange for external sodium ions. The net effect would be to shuttle intracellular Pb(2+) to extracellular dimercaptosuccinic acid thereby enhancing its effectiveness. Thus, monensin may be useful for the treatment of Pb intoxication when applied in combination with hydrophilic Pb(2+) chelators

Conformational Changes in Conantokin-G Induced upon Binding of Calcium and Magnesium as Revealed by NMR Structural Analysis

The apo- and metal-bound solution conformations of synthetic conantokin-G (con-G, G1Egamma gammaL5Q gamma NQgamma 10LIRgamma K15SN-CONH2, gamma = gamma-carboxyglutamic acid), an antagonist of N-methyl-D-aspartate receptor-derived neuronal ion channels, have been examined by one- and two-dimensional 1H NMR at neutral pH. A complete structure for the Mg2+-loaded peptide was defined by use of distance geometry calculations and was found to exist as an alpha-helix that spans the entire peptide. The alpha-helical nature of Mg2+/con-G was also supported by the small values (<5.5 Hz) of the 3JHNalpha coupling constants measured for amino acid residues 3-5, 8, 9, and 11-16, and the small values (<4 ppb/K) of the temperature coefficients observed for the alphaNH protons of residues 5-17. This conformation contrasted with that obtained for apo-con-G, which was nearly structureless in solution. Docking of Mg2+ into con-G was accomplished by use of the genetic algorithm/molecular dynamics simulation method, employing the NMR-derived Mg2+-loaded structure for initial coordinates in the midpoint calculations. For the 3 Mg2+/con-G model, it was found that binding of one Mg2+ ion is stabilized by oxygen atoms from three gamma-carboxylates of Gla3, Gla4, and Gla7; another Mg2+ is coordinated by two oxygen atoms, one from each of the gamma-carboxylates of Gla7; and a third metal ion through three donor oxygen atoms of gamma-carboxylates from Gla10 and Gla14. As shown from direct metal binding measurements to mutant con-G peptides, these latter two Gla residues probably stabilized the tightest binding Mg2+ ion. Circular dichroism studies of these same peptide variants demonstrated that all Gla residues contribute to the adoption of the Mg2+-dependent alpha-helical conformation in con-G. The data obtained in this investigation provide a molecular basis for the large conformational alteration observed in apo-con-G as a result of divalent cation binding and allow assessment of the roles of individual Gla residues in defining certain of the structure-function properties of con-G

Joint management of shared resources as an alternative approach for addressing maritime boundary disputes : the Kenya-Somalia maritime boundary dispute

Socio-economic security has motivated African states to explore natural resources in areas of overlapping maritime claims. However, Africa’s maritime boundaries are characterized by unresolved disputes. Resolution of these disputes is time-consuming, expensive and can undermine the state’s ability to exploit natural resources. The Somalia and Kenya maritime dispute under litigation with the International Court of Justice demonstrates the continental commitment to peaceful resolution. Citing cases from across Africa, we discuss outright delimitation or Joint Management Zones (JMZs) as means to address disputes over shared resources, particularly transboundary fisheries, which have received little attention. Reframing the Kenya-Somalia maritime dispute resolution process as cooperation over fisheries management will have spill-over effects into greater diplomatic relations. Fish do not abide by maritime boundaries. As such, we posit that the peaceful resolution of maritime boundary disputes lies in Africa’s ability to consider settlements by way of JMZs to motivate sustainable use of natural resources.PostprintPeer reviewe

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology

Functional Dissection of Streptococcus pyogenes M5 Protein: the Hypervariable Region is Essential for Virulence

The surface-localized M protein of Streptococcus pyogenes is a major virulence factor that inhibits phagocytosis, as determined ex vivo. Because little is known about the role of M protein in vivo we analyzed the contribution of different M protein regions to virulence, using the fibrinogen (Fg)-binding M5 protein and a mouse model of acute invasive infection. This model was suitable, because M5 is required for mouse virulence and binds mouse and human Fg equally well, as shown here. Mixed infection experiments with wild type bacteria demonstrated that mutants lacking the N-terminal hypervariable region (HVR) or the Fg-binding B-repeat region were strongly attenuated, while a mutant lacking the conserved C-repeats was only slightly attenuated. Because the HVR of M5 is not required for phagocytosis resistance, our data imply that this HVR plays a major but unknown role during acute infection. The B-repeat region is required for phagocytosis resistance and specifically binds Fg, suggesting that it promotes virulence by binding Fg. However, B-repeat mutants were attenuated even in Fg-deficient mice, implying that the B-repeats may have a second function, in addition to Fg-binding. These data demonstrate that two distinct M5 regions, including the HVR, are essential to virulence during the early stages of an infection. In particular, our data provide the first in vivo evidence that the HVR of an M protein plays a major role in virulence, focusing interest on the molecular role of this region

Income in Adult Survivors of Childhood Cancer.

INTRODUCTION: Little is known about the impact of childhood cancer on the personal income of survivors. We compared income between survivors and siblings, and determined factors associated with income. METHODS: As part of the Swiss Childhood Cancer Survivor Study (SCCSS), a questionnaire was sent to survivors, aged ≥18 years, registered in the Swiss Childhood Cancer Registry (SCCR), diagnosed at age 4'500 CHF), even after we adjusted for socio-demographic and educational factors (OR = 0.46, p<0.001). Older age, male sex, personal and parental education, and number of working hours were associated with high income. Survivors of leukemia (OR = 0.40, p<0.001), lymphoma (OR = 0.63, p = 0.040), CNS tumors (OR = 0.22, p<0.001), bone tumors (OR = 0.24, p = 0.003) had a lower income than siblings. Survivors who had cranial irradiation, had a lower income than survivors who had no cranial irradiation (OR = 0.48, p = 0.006). DISCUSSION: Even after adjusting for socio-demographic characteristics, education and working hours, survivors of various diagnostic groups have lower incomes than siblings. Further research needs to identify the underlying causes