Effective Sol-Gel Nanocoatings on ZnO Electrodes for Suppressing Recombination in Dye-Sensitized Solar Cells

Attempts have been made to improve the performance of dye-sensitized solar cells by forming metal-oxide nanocoating layers on ZnO electrodes by a sol-gel transformation. SiO2, Nb2O5, TiO2, or ZrO2 nanocoating layers could be formed by dipping ZnO films into metal alkoxide solutions of low concentrations and subsequent heat treatments. The performance of DSSCs using the coated ZnO electrodes depends strongly on the structure of coating layers such as the thickness and the surface coverage, which are significantly influenced by the coating conditions. In particular, SiO2 and Nb2O5 coating layers are effective to suppress the recombination by constructing the energy barrier at the ZnO/electrolyte interface and enhance energy conversion efficiency. It is found that the coating layers also hinder the grain growth of ZnO, contributing to the enhanced cell performance as well

Factors associated with development and distribution of granular/fuzzy astrocytes in neurodegenerative diseases

Granular/fuzzy astrocytes (GFAs), a subtype of “aging‐related tau astrogliopathy,” are noted in cases bearing various neurodegenerative diseases. However, the pathogenic significance of GFAs remains unclear. We immunohistochemically examined the frontal cortex, caudate nucleus, putamen and amygdala in 105 cases composed of argyrophilic grain disease cases (AGD, N = 26), and progressive supranuclear palsy (PSP, N = 10), Alzheimer’s disease (AD, N = 20) and primary age‐related tauopathy cases (PART, N = 18) lacking AGD, as well as 31 cases bearing other various neurodegenerative diseases to clarify (i) the distribution patterns of GFAs in AGD, and PSP, AD and PART lacking AGD, (ii) the impacts of major pathological factors and age on GFA formation and (iii) immunohistochemical features useful to understand the formation process of GFAs. In AGD cases, GFAs consistently occurred in the amygdala (100%), followed by the putamen (69.2%) and caudate nucleus and frontal cortex (57.7%, respectively). In PSP cases without AGD, GFAs were almost consistently noted in all regions examined (90–100%). In AD cases without AGD, GFAs were less frequent, developing preferably in the putamen (35.0%) and caudate nucleus (30.0%). PART cases without AGD had GFAs most frequently in the amygdala (35.3%), being more similar to AGD than to AD cases. Ordered logistic regression analyses using all cases demonstrated that the strongest independent factor of GFA formation in the frontal cortex and striatum was the diagnosis of PSP, while that in the amygdala was AGD. The age was not significantly associated with GFA formation in any region. In GFAs in AGD cases, phosphorylation and conformational change of tau, Gallyas‐positive glial threads indistinguishable from those in tufted astrocytes, and the activation of autophagy occurred sequentially. Given these findings, AGD, PSP, AD and PART cases may show distinct distributions of GFAs, which may provide clues to predict the underlying processes of primary tauopathies

タシン ヘイバン デンキョク ケイ ヲ モチイタ バリア ホウデン ト オゾン セイセイ

Relationship between barrier discharge characteristics and ozone generation under ac voltage application has been investigated for triple needles-plane configuration with two different needle-tip radii (r=l5, 80μm) in dry air. Characteristics of barrier discharge and ozone generation depend on the needle-tip radius. Especially, ozone concentration and ozone generation efficiency for the triple needles with r=80μm were higher than those for the needles with r=l5μm. These results can be interpreted by the effect of the space charges and accumulated charges induced by corona discharge and barrier discharge on the space for ozone generation

Unexpected effects of azole transporter inhibitors on antifungal susceptibility in Candida glabrata and other pathogenic Candida species

The pathogenic fungus Candida glabrata is often resistant to azole antifungal agents. Drug efflux through azole transporters, such as Cdr1 and Cdr2, is a key mechanism of azole resistance and these genes are under the control of the transcription factor Pdr1. Recently, the monoamine oxidase A (MAO-A) inhibitor clorgyline was shown to inhibit the azole efflux pumps, leading to increased azole susceptibility in C. glabrata. In the present study, we have evaluated the effects of clorgyline on susceptibility of C. glabrata to not only azoles, but also to micafungin and amphotericin B, using wild-type and several mutant strains. The addition of clorgyline to the culture media increased fluconazole susceptibility of a C. glabrata wild-type strain, whereas micafungin and amphotericin B susceptibilities were markedly decreased. These phenomena were also observed in other medically important Candida species, including Candida albicans, Candida parapsilosis, Candida tropicalis, and Candida krusei. Expression levels of CDR1, CDR2 and PDR1 mRNAs and an amount of Cdr1 protein in the C. glabrata wild-type strain were highly increased in response to the treatment with clorgyline. However, loss of Cdr1, Cdr2, Pdr1, and a putative clorgyline target (Fms1), which is an ortholog of human MAO-A, or overexpression of CDR1 did not affect the decreased susceptibility to micafungin and amphotericin B in the presence of clorgyline. The presence of other azole efflux pump inhibitors including milbemycin A4 oxime and carbonyl cyanide 3-chlorophenylhydrazone also decreased micafungin susceptibility in C. glabrata wild-type, Δcdr1, Δcdr2, and Δpdr1 strains. These findings suggest that azole efflux pump inhibitors increase azole susceptibility but concurrently induce decreased susceptibility to other classes of antifungals independent of azole transporter functions

乾燥空気中における3針-平板電極のバリア放電とオゾン生成

A relation of barrier discharge characteristics to ozone generation under ac voltage application has been investigated for various distances between three needle-tips (d=0mm～7.0mm) at constant distance between needle tip and plane (g=3.0mm) in dry air. Characteristics of the barrier discharge and ozone generation are changed by the needle-tips distance. Those changes have been caused by the influence of tip needle each other and distance between three needle-tips. It is considered that the influence is caused by space charge and accumulated charge suggested from discharge image by still camera and CCD camera. And ozone generation efficiency was estimated by power consumption and ozone concentration. As a result, when the distance between three needle-tips is narrow, the above-mentioned influence is strengthened. And in this case, ozone generation efficiency improves

Synthesis of Silver-Strontium Titanate Hybrid Nanoparticles by Sol-Gel-Hydrothermal Method

Silver (Ag) nanoparticle-loaded strontium titanate (SrTiO3) nanoparticles were attempted to be synthesized by a sol-gel-hydrothermal method. We prepared the titanium oxide precursor gels incorporated with Ag+ and Sr2+ ions with various molar ratios, and they were successfully converted into the Ag-SrTiO3 hybrid nanoparticles by the hydrothermal treatment at 230 °C in strontium hydroxide aqueous solutions. The morphology of the SrTiO3 nanoparticles is dendritic in the presence and absence of Ag+ ions. The precursor gels, which act as the high reactive precursor, give rise to high nucleation and growth rates under the hydrothermal conditions, and the resultant diffusion-limited aggregation phenomena facilitate the dendritic growth of SrTiO3. From the field-emission transmission electron microscope observation of these Ag-SrTiO3 hybrid nanoparticles, the Ag nanoparticles with a size of a few tens of nanometers are distributed without severe agglomeration, owing to the competitive formation reactions of Ag and SrTiO3

Fabrication of layered hydroxide zinc nitrate films and their conversion to ZnO nanosheet assemblies for use in dye-sensitized solar cells

Layered hydroxide zinc nitrate (LHZN; Zn5(NO3)2(OH)8·xH2O) films were fabricated on glass or plastic substrates by a chemical bath deposition method combined with a homogeneous precipitation in methanolic solutions. High- or low-temperature pyrolytic decomposition of the LHZN films having two-dimensional morphology was attempted to obtain porous ZnO nanosheet-assembly films. The LHZN films were converted into porous ZnO films by pyrolyzing at temperatures above 400 °C, while porous LHZN/ZnO hybrid films were obtained by pyrolyzing at a lower temperature of 120 °C without morphological changes. The pyrolyzed ZnO films were applied to dye-sensitized solar cells (DSSCs), resulting in the generation of relatively high open-circuit voltages. The low-temperature pyrolysis enabled us to fabricate the LHZN/ZnO film even on the plastic substrate. Actually a cell using the LHZN/ZnO film on an indium tin oxide-coated polyethylene naphthalate substrate showed an energy conversion efficiency of 2.08% with a high open-circuit voltage around 0.70 V