Hybrid TiO₂–SnO₂ Nanotube Arrays for Dye-Sensitized Solar Cells

Tin oxide (SnO₂) is a promising wide band gap semiconductor material for dye-sensitized solar cells (DSCs) because of its high bulk electron mobility. Employing vertically ordered 1-D nanostructures of SnO₂ as the photoanode may overcome the limit of current DSCs by using new redox mediators with faster kinetics than currently used ones. Synthesizing such nanostructures and integrating them into DSCs, however, has been proven challenging. Here, we demonstrate that, by using ZnO nanowires as a sacrificial template, vertically aligned SnO₂ nanotube arrays may be feasibly synthesized through a liquid-phase conversion process, and the synthesized SnO₂ nanotubes can be further coated with a thin layer of TiO₂ to form hybrid TiO₂–SnO₂ nanotube arrays. Both the resulting SnO₂ and hybrid TiO₂–SnO₂ nanotube arrays are used to fabricate DSCs, and the best performing cell delivers a promising efficiency of 3.53%. Transient photovoltage measurements indicate that the electron recombination lifetime in hybrid TiO₂–SnO₂ nanotubes is significantly larger than those in TiO₂ nanotubes, ZnO nanowires, and films of sintered TiO₂ nanoparticles, suggesting promise of the TiO₂-coated SnO₂ nanotubes for further improvement of DSCs

High-Efficiency Solid-State Dye-Sensitized Solar Cells Based on TiO₂-Coated ZnO Nanowire Arrays

Replacing the liquid electrolytes in dye-sensitized solar cells (DSCs) with solid-state hole-transporting materials (HTMs) may solve the packaging challenge and improve the long-term stability of DSCs. The efficiencies of such solid-state DSCs (ss-DSCs), however, have been far below the efficiencies of their counterparts that use liquid electrolytes, primarily due to the challenges in filling HTMs into thick enough sensitized films based on sintered TiO₂ nanoparticles. Here we report fabrication of high-efficiency ss-DSCs using multilayer TiO₂-coated ZnO nanowire arrays as the photoanodes. The straight channel between the vertically aligned nanostructures combined with a newly developed multistep HTM filling process allows us to effectively fill sensitized films as thick as 50 μm with the HTMs. The resulting ss-DSCs yield an average power conversion efficiency of 5.65%

Sorting Short Fragments of Single-Stranded DNA with an Evolving Electric Double Layer

We demonstrate a new procedure for separation of single-stranded DNA (ssDNA) fragments that are anchored to the surface of a gold electrode by end hybridization. The new separation procedure takes advantage of the strong yet evolving nonuniform electric field near the gold surface in contact with a buffer solution gradually being diluted with deionized water. Separation of short ssDNA fragments is demonstrated by monitoring the DNA at the gold surface with <i>in situ</i> fluorescence measurement. The experimental results can be rationalized with a simple theoretical model of electric double layer that relates the strength of the surface pulling force to the ionic concentration of the changing buffer solution

Is π‑Stacking Prone To Accelerate Singlet–Singlet Energy Transfers?

π-Stacking is the most common structural feature that dictates the optical and electronic properties of chromophores in the solid state. Herein, a unidirectional singlet–singlet energy-transfer dyad has been designed to test the effect of π-stacking of zinc­(II) porphyrin, <b>[Zn</b>_<b>2</b><b>]</b>, as a slipped dimer acceptor using a BODIPY unit, <b>[bod]</b>, as the donor, bridged by the linker C₆H₄CCC₆H₄. The rate of singlet energy transfer, <i>k</i>_ET(S₁), at 298 K (<i>k</i>_ET(S₁) = 4.5 × 10¹⁰ s^–1) extracted through the change in fluorescence lifetime, τ_F, of <b>[bod]</b> in the presence (27.1 ps) and the absence of <b>[Zn</b>_<b>2</b><b>]</b> (4.61 ns) from Streak camera measurements, and the rise time of the acceptor signal in femtosecond transient absorption spectra (22.0 ps), is faster than most literature cases where no π-stacking effect exists (i.e., monoporphyrin units). At 77 K, the τ_F of <b>[bod]</b> increases to 45.3 ps, indicating that <i>k</i>_ET(S₁) decreases by 2-fold (2.2 × 10¹⁰ s^–1), a value similar to most values reported in the literature, thus suggesting that the higher value at 298 K is thermally promoted at a higher temperature

FeCo₂S₄ Nanosheet Arrays Supported on Ni Foam: An Efficient and Durable Bifunctional Electrocatalyst for Overall Water-Splitting

Efficient and stable bifunctional electrocatalysts composed of Earth-abundant elements are crucial to the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). Herein, FeCo₂S₄ nanosheet arrays loaded on Ni foam (NF) are synthesized and first employed as a bifunctional electrocatalyst for full water-splitting. Remarkably, the self-assembled, binder-free, and cost-effective FeCo₂S₄/NF electrode shows high OER catalytic activity, which only requires an overpotential of 270 and 290 mV to achieve current densities of 50 and 100 mA cm^–2, respectively. Moreover, the FeCo₂S₄/NF electrode exhibits considerable OER stability over 20 h at a static current density of 50 mA cm^–2, with negligible potential change in alkaline electrolyte. Meanwhile, when serving as a catalyst for the HER under alkaline conditions, an overpotential of just 132 mV is required to deliver the current density of 10 mA cm^–2. The structural investigation demonstrates the formation of a Co­(Fe)-(oxy)­hydroxides layer on the catalyst surface during the OER test, which could be the real active species. Furthermore, because of the high catalytic activity and stability of this bifunctional electrocatalyst, we prepared a high-performance overall water electrolyzer that could achieve a current density of 10 mA cm^–2 at a cell voltage of 1.56 V

IL-17A Induces Endothelial Inflammation in Systemic Sclerosis via the ERK Signaling Pathway

<div><p>Recent reports have demonstrated that endothelial cells are involved in vascular inflammatory injury in systemic sclerosis (SSc) and interleukin-17A (IL-17A) plays a crucial role in the pathogenesis of SSC. However, little is known about the effects of IL-17A on endothelial cell inflammation in SSC. The aim of our study was to investigate the role of IL-17A in endothelial inflammation. Here, we showed that IL-17A mRNA and protein levels were augmented in the peripheral blood and more IL-17⁺ lymphocytes infiltrated in the perivascular areas in the involved skin of SSC patients. SSC patient serum induced chemokine and adhesion molecule expression in HUVECs, which was blocked by IL-17A neutralization. IL-17A alone induced chemokine and adhesion molecule expression and promoted T cell-HUVEC adhesion. Extracellular signal-regulated kinase (ERK) inhibition and IL-17A neutralization prominently inhibited chemokine and adhesion molecule expression and blocked T cell-HUVEC adhesion. IL-17A derived from SSC patient serum mediated endothelial cells inflammation by up-regulating chemokines and adhesion molecules, which was blocked by ERK inhibition. These data imply that ERK signal pathway might play a key role in the progression of endothelial injury induced by IL-17A in SSC. </p> </div

IL-17A promotes the expression of adhesion molecules and chemokines in HUVECs and HMEC-1.

<p>(A, D) HUVECs and HMEC-1 were treated with IL-17A at a range of concentrations for 12 h, and mRNA expression of CCL-20 and CXCR-4 was measured by real-time RT-PCR (Comparing 0 ng/ml IL-17A and 20ng/ml IL-17A, *, P<0.05). (B, E) HUVECs and HMEC-1 were treated with IL-17A at a range of concentrations for 12 h, and mRNA expression of adhesion molecules VCAM-1 and ICAM-1 was measured by real-time RT-PCR (Comparing 0 ng/ml IL-17A and 20ng/ml IL-17A, *, P<0.05). (C, F) HUVECs and HMEC-1 were treated with IL-17A at a range of concentrations for 24 h, and protein expression of CCL-20, CXCR-4, VCAM-1, and ICAM-1 was measured by western blot. All experiments were conducted three separate times, and representative data are presented. </p

Increased expression of IL-17 in SSc patients.

<p>(A) The concentration of IL-17A in the sera of SSc patients (n=20) and healthy controls (n=16) was detected by ELISA. The ELISAs were repeated three times, and the results represent the mean ± S.D. (*P<0.05). (B) Total RNA from PBMCs in SSc patients (n=20) and healthy controls (n=16) was extracted, and real-time RT-PCR analysis was performed for IL-17A. The results of real-time RT-PCR were averaged from three separate experiments (n = 3) and are presented as relative gene expression ±S.D. (*P<0.05). (C) H&E stain of skin in SSc. (D) Expression of IL-17A was detected by immunohistochemistry in the dermis layer of SSc patients. (E) Expression of IL-17A was detected by immunohistochemistry in the subcutaneous tissue of SSc patients. (F) H&E stain of skin in healthy controls. (G) Expression of IL-17A was detected by immunohistochemistry in the dermis layer of healthy controls. (H) The expression of IL-17A was detected by immunohistochemistry in subcutaneous tissue of healthy controls. Arrows show typical positive cells. Scale bars =100 μm.</p

Factors Associated with Interstitial Lung Disease in Patients with Polymyositis and Dermatomyositis: A Systematic Review and Meta-Analysis

<div><p>Objectives</p><p>Interstitial lung disease (ILD) is an extramuscular manifestation that results in increased morbidity and mortality from polymyositis (PM) and dermatomyositis (DM). The aim of this study was to systematically evaluate risk factors associated with the development of ILD in PM/DM.</p><p>Methods</p><p>Observational studies were identified from searching PubMed, Medline, Embase, and the Cochrane Library. Pooled odds ratios (ORs) or standardized mean differences (SMDs) and corresponding 95% confidence intervals (CIs) were obtained for the relationships between risk factors and ILD in PM/DM using either fixed- or random-effects models, whichever were appropriate. Heterogeneity tests, sensitivity analyses, and publication bias assessments were also performed.</p><p>Results</p><p>Twenty-three studies were selected for a meta-analysis that included 834 patients and 1245 control subjects. Risk factors that may have increased the risk of developing ILD in PM/DM patients included older age at diagnosis (SMD, 0.35; 95% CI, 0.18–0.52; <i>P</i> < 0.0001), arthritis/arthralgia (OR, 3.17; 95% CI, 1.99–5.04; <i>P</i> < 0.00001), fever (OR, 2.31; 95% CI, 1.42–3.76; <i>P</i> = 0.0007), presence of anti-Jo-1 antibodies (OR, 3.34; 95% CI, 2.16–5.16; <i>P</i> < 0.00001), elevated erythrocyte sedimentation rate (ESR; SMD, 0.48; 95% CI, 0.32–0.64; <i>P</i> < 0.00001), presence of anti-MDA5 antibodies (OR, 18.26; 95% CI, 9.66–34.51; <i>P</i> < 0.00001), and elevated C-reactive protein level (CRP; OR, 3.50; 95% CI, 1.48–8.28; <i>P</i> = 0.004). Meanwhile, malignancy (OR, 0.36; 95% CI, 0.18–0.72; <i>P</i> = 0.004) reduced the risk of developing ILD in PM/DM patients.</p><p>Conclusion</p><p>Our meta-analysis results suggest that the association between PM/DM and ILD may be due to such risk factors as older age at diagnosis, arthritis/arthralgia, fever, presence of anti-Jo-1 antibodies, elevated ESR, presence of anti-MDA5 antibodies, and elevated CRP level, while malignancy was associated with a reduced risk of developing ILD. Thus, these variables may be used to guide screening processes for ILD in patients with PM/DM.</p></div

Plasmonic Probing Single-Cell Bio-Current Waves with a Shrinking Magnetite Nanoprobe

Probing of the single-cell level extracellular electron transfer highlights the maximum output current for microbial fuel cells (MFCs) at hundreds of femtoampere per cell, which is difficult to achieve by existing devices. Past studies focus on the external factors for boosting charge-extraction efficiency from bacteria. Here, we elucidate the intracellular factors that determine this output limit by monitoring the respiratory-driven shrinking kinetics of a single magnetite nanoprobe immobilized on a single Shewanella oneidensis MR-1 cell with plasmonic imaging. Quantified dissolving of nanoprobes unveils a previously undescribed bio-current fluctuation between 0 and 2.7 fA on a ∼40 min cycle. Simultaneously tracing of endogenous oscillations indicates that the bio-current waves are correlated with the periodic cellular electrokinesis. The unsynchronized electron transfer capability in the cell population results in the mean current of 0.24 fA per cell, significantly smaller than in single cells. It explains why the averaged output current of MFCs cannot reach the measured single-cell currents. This work offers a different perspective to improve the power output by extending the active episodes of the bio-current waves