79 research outputs found

    Flexible ultraviolet and ambient light sensor based on nanomaterial network fabricated by using selective and localized wet-chemical reactions

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    We report ZnO nanowire- and TiO_2 nanotube-based light sensors on flexible polymer substrates fabricated by localized hydrothermal synthesis and liquid phase deposition (LPD). This method realized simple and cost-effective in situ synthesis and integration of one-dimensional ZnO and TiO_2 nanomaterials. The fabricated sensor devices with ZnO nanowires and TiO_2 nanotubes show very high sensitivity and quick response to the ultraviolet (UV) and ambient light, respectively. In addition, our direct synthesis and integration method result in mechanical robustness under external loading such as static and cyclic bending because of the strong bonding between the nanomaterial and the electrode. By controlling the reaction time of the LPD process, the Ti/Zn ratio could be simply modulated and the spectral sensitivity to the light in the UV to visible range could be controlled

    Effect of few-walled carbon nanotube crystallinity on electron field emission property

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    We discuss the influence of few-walled carbon nanotubes (FWCNTs) treated with nitric acid and/or sulfuric acid on field emission characteristics. FWCNTs/tetraethyl orthosilicate (TEOS) thin film field emitters were fabricated by a spray method using FWCNTs/TEOS sol one-component solution onto indium tin oxide (ITO) glass. After thermal curing, they were found tightly adhered to the ITO glass, and after an activation process by a taping method, numerous FWCNTs were aligned preferentially in the vertical direction. Pristine FWCNT/ TEOS-based field emitters revealed higher current density, lower turn-on field, and a higher field enhancement factor than the oxidized FWCNTs-based field emitters. However, the unstable dispersion of pristine FWCNT in TEOS/N,N-dimethylformamide solution was not applicable to the field emitter fabrication using a spray method. Although the field emitter of nitric acid-treated FWCNT showed slightly lower field emission characteristics, this could be improved by the introduction of metal nanoparticles or resistive layer coating. Thus, we can conclude that our spray method using nitric acid-treated FWCNT could be useful for fabricating a field emitter and offers several advantages compared to previously reported techniques such as chemical vapor deposition and screen printing.ope

    Role of histamine-mediated macrophage differentiation in clearance of metastatic bacterial infection

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    Macrophages are highly heterogeneous immune cells with a role in maintaining tissue homeostasis, especially in activating the defense response to bacterial infection. Using flow cytometric and single-cell RNA-sequencing analyses of peritoneal cells, we here show that small peritoneal macrophage and immature macrophage populations are enriched in histamine-deficient (Hdc-/-) mice, characterized by a CD11bmiF4/80loCCR2+MHCIIhi and CD11bloF4/80miTHBS1+IL-1α+ phenotype, respectively. Molecular characterization revealed that immature macrophages represent an abnormally differentiated form of large peritoneal macrophages with strong inflammatory properties. Furthermore, deficiency in histamine signaling resulted in significant impairment of the phagocytic activity of peritoneal macrophage populations, conferring high susceptibility to bacterial infection. Collectively, this study reveals the importance of histamine signaling in macrophage differentiation at the molecular level to maintain tissue homeostasis, offering a potential therapeutic target for bacterial infection-mediated diseases

    Biased TAS2R Bronchodilators Inhibit Airway Smooth Muscle Growth by Downregulating pERK1/2

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    Bitter taste receptor (TAS2R) agonists dilate airways by receptor-dependent smooth muscle relaxation. Besides coupling to relaxation, we have found that human airway smooth muscle (HASM) cell TAS2Rs activate (phosphorylate) ERK1/2, but the cellular effects are not known. Here we show in HASM cells that TAS2R agonists initially stimulate pERK1/2, but by 24 hrs cause a marked (50-70%) downregulation of pERK1/2 without a change in total ERK1/2. It was hypothesized that TAS2R agonists suppress cell growth through this pERK1/2 downregulation. Agonist-dependent inhibition of cell proliferation was indeed found in HASM cells derived from normal and asthmatic human lungs, as well as an immortalized HASM cell line. pERK1/2 downregulation was linked to downregulation of the upstream kinase MEK1/2. Various structurally diverse TAS2R agonists evoked a range of inhibition of HASM proliferation, the magnitude of which directly correlated with the downregulation of pERK1/2 (R2 = 0.86). Some TAS2R agonists were as effective in suppressing growth as pharmacological inhibitors of Raf1 and MEK1/2. siRNA silencing of TAS2Rs (subtypes 10, 14, 31) ablated the pERK1/2 and growth inhibiting effects of TAS2R agonists. These phenotypes were attenuated by inhibiting the TAS2R G-protein Gα, and by knocking-down β-arrestin1/2, indicating a dual pathway, although there may be additional mechanisms involved in this HASM TAS2R multidimensional signaling. Thus TAS2R agonist structure can be manipulated to maintain the relaxation response, and be biased towards suppression of HASM growth. The latter response is of potential therapeutic benefit in asthma, where an increase in smooth muscle mass contributes to airway obstruction

    Distinct patterns of Internet and smartphone-related problems among adolescents by gender: Latent class analysis

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    Background and objectives The ubiquitous Internet connections by smartphones weakened the traditional boundaries between computers and mobile phones. We sought to explore whether smartphone-related problems differ from those of computer use according to gender using latent class analysis (LCA). Methods After informed consents, 555 Korean middle-school students completed surveys on gaming, Internet use, and smartphone usage patterns. They also completed various psychosocial instruments. LCA was performed for the whole group and by gender. In addition to ANOVA and χ2 tests, post-hoc tests were conducted to examine differences among the LCA subgroups. Results In the whole group (n = 555), four subtypes were identified: dual-problem users (49.5%), problematic Internet users (7.7%), problematic smartphone users (32.1%), and “healthy” users (10.6%). Dual-problem users scored highest for addictive behaviors and other psychopathologies. The gender-stratified LCA revealed three subtypes for each gender. With dual-problem and healthy subgroup as common, problematic Internet subgroup was classified in the males, whereas problematic smartphone subgroup was classified in the females in the gender-stratified LCA. Thus, distinct patterns were observed according to gender with higher proportion of dual-problem present in males. While gaming was associated with problematic Internet use in males, aggression and impulsivity demonstrated associations with problematic smartphone use in females. Conclusions An increase in the number of digital media-related problems was associated with worse outcomes in various psychosocial scales. Gaming may play a crucial role in males solely displaying Internet-related problems. The heightened impulsivity and aggression seen in our female problematic smartphone users requires further research

    Als wär’ es ein Stuck von uns . . . German Politics and Society Traverses Twenty Years of United Germany

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    This essay looks at postunification Germany through the pages of German Politics and Society. The articles published during this period reveal the evolution of intellectuals' understanding of the unified country—concerns that mirrored changes in social, political, and cultural reality. Of course, academics are beholden to their own histories and Weltanschauung, a fact that produced, at times, prescient, sometimes fragmentary, and sometimes alarmist interpretations and analyses of the country in an attempt to provide orientation. Nevertheless, this review shows how German watchers have slowly up-dated their paradigms and are now not worrying as much about a mellowed, less German country that has fascinated them over the decades.Histor
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