In situ synthesis of copper nanoparticles encapsulated by nitrogen-doped graphene at room temperature via solution plasma.

Metal-carbon core-shell nanostructures have gained research interest due to their better performances in not only stability but also other properties, such as catalytic, optical, and electrical properties. However, they are limited by complicated synthesis approaches. Therefore, the development of a simple method for the synthesis of metal-carbon core-shell nanostructures is of great significance. In this work, a novel Cu-core encapsulated by a N-doped few-layer graphene shell was successfully synthesized in a one-pot in-liquid plasma discharge, so-called solution plasma (SP), to our knowledge for the first time. The synthesis was conducted at room temperature and atmospheric pressure by using a pair of copper electrodes submerged in a DMF solution as the precursor. The core-shell structure of the obtained products was confirmed by HR-TEM, while further insight information was explained from the results of XRD, Raman, and XPS measurements. The obtained Cu-core encapsulated by the N-doped few-layer graphene shell demonstrated relatively high stability in acid media, compared to the commercial bare Cu particles. Moreover, the stability was found to depend on the thickness of the N-doped few-layer graphene shell which can be tuned by adjusting the SP operating conditions.

Serious psychological distress, sex, and falls among the elderly.

Serious psychological distress and falls are two major public health problems among the elderly. This study aims to test the hypothesis that although serious psychological distress can increase the risks of falls among the elderly, it tends to affect elderly women more than elderly men. Data of this study are from the 2011 California Health Survey Interviews (CHIS). We extracted a sample of 13,153 respondents aged 65 and older for this study, including 8,087 females and 5,066 males. We tested both unadjusted and adjusted interaction effects using bivariate and multivariate logistic regression analysis. Elderly women with serious psychological distress had the greatest likelihood of falls as compared to men with serious psychological distress and men and women without serious psychological distress. With respect to the covariates, limitations of physical activity and poor self-rated health status, Asian race, and older age were more likely to be associated with falls. This study provides further information on sex disparities of falls among the elderly such that serious psychological distress has a greater impact on falls for elderly women than elderly men. Thus, the findings of our studies suggest that mental health services and intervention can be useful to prevent falls for elderly women.

Vasoactive intestinal peptide loss leads to impaired CNS parenchymal T-cell infiltration and resistance to experimental autoimmune encephalomyelitis.

The neuropeptide vasoactive intestinal peptide (VIP) has been shown to inhibit macrophage proinflammatory actions, promote a positive Th2/Th1 balance, and stimulate regulatory T-cell production. The fact that this peptide is highly efficacious in animal models of inflammatory diseases such as collagen-induced arthritis and experimental autoimmune encephalomyelitis (EAE) suggests that the endogenous peptide might normally provide protection against such pathologies. We thus studied the response of VIP-deficient (i.e., VIP KO) mice to myelin oligodendrocyte protein-induced EAE. Surprisingly, VIP KO mice were almost completely resistant to EAE, with delayed onset and mild or absent clinical profile. Despite this, flow cytometric analyses and antigen-rechallenge experiments indicated that myelin oligodendrocyte protein-treated VIP KO mice exhibited robust Th1/Th17 cell inductions and antigen-specific proliferation and cytokine responses. Moreover, adoptive transfer of lymphocytes from immunized VIP KO mice to WT recipients resulted in full-blown EAE, supporting their encephalitogenic potential. In contrast, transfer of encephalitogenic WT cells to VIP KO hosts did not produce EAE, suggesting that loss of VIP specifically affected the effector phase of the disease. Histological analyses indicated that CD4 T cells entered the meningeal and perivascular areas of VIP-deficient mice, but that parenchymal infiltration was strongly impaired. Finally, VIP pretreatment of VIP KO mice before immunization was able to restore their sensitivity to EAE. These results indicate that VIP plays an unanticipated permissive and/or proinflammatory role in the propagation of the inflammatory response in the CNS, a finding with potential therapeutic relevance in autoimmune neuroinflammatory diseases such as multiple sclerosis.

Iron binding saturation and genotypic testing for hereditary hemochromatosis in patients with liver disease.

We compared the results of HFE genotype with tests for iron binding saturation (IBS) in 190 consecutive patients with liver disease using 2 IBS cutoff levels: 45% and 60%. Saturation was more than 45% in 117 patients (61.6%) and more than 60% in 89 (46.8%). The number of patients (10) with the highest-risk HFE genotype (C282Y homozygote) was higher than expected. Elevated IBS cannot be used to predict genotype. There was a modest association of C282Y homozygosity with increased IBS (7 of 10, saturation >45% and 6 of 10, >60%). There was poor correlation of elevated saturation with other genotypes containing 1 or more HFE variants. Patients with a wild-type genotype (lacking HFE variants) and elevated IBS were far more likely to have an iron binding capacity less than 250 microg/dL (<44.8 micromol/L) than those with saturation values less than 45%, suggesting that a significant percentage of elevated IBS test results in liver disease are false-positives associated with decreased synthetic capacity. Nevertheless, an appreciable number of patients with elevated IBS had normal iron binding capacity, indicating the complexity of relationships among iron absorption and binding, disease status, HFE genotype, and other potential modifying factors in liver disease.

Differential substrate-induced signaling through the TonB-dependent transporter BtuB.

The BtuB transporter mediates high-affinity binding and TonB-dependent active transport of vitamin B12 [cyanocobalamin (CNCbl)] across the outer membrane of Escherichia coli. A characteristic feature of TonB-dependent transporters is the Ton box, a conserved sequence near the N terminus and exposed to the periplasm. Crosslinking to TonB and site-directed spin labeling indicated that the Ton box of BtuB undergoes a substantial conformational transition in response to CNCbl binding, but only slight movement was seen in crystal structures. An in vivo method of detecting substrate-induced changes in the Ton box environment measured reaction of a biotin maleimide derivative with cysteine substitutions through the N-terminal region of BtuB between positions 1 and 31. The degree of maleimide labeling of different residues correlated with their accessibility in the crystal structure. Labeling of many positions was increased strongly when CNCbl was present, consistent with the undocking of this region proposed from spin-labeling analyses. The receptor-binding domain of colicin E3, which binds to BtuB competitively with CNCbl, resulted in decreased labeling. Both substrate-induced transitions occur in and beyond the Ton box and were affected by transport-uncoupling substitutions. Thus, two transport substrates that bind competitively to the extracellular face of BtuB stabilize opposite transitions of the Ton box.