60 research outputs found
CO<sub>2</sub> Reduction to Methanol on TiO<sub>2</sub>‑Passivated GaP Photocatalysts
In the past, the electrochemical
instability of III–V semiconductors
has severely limited their applicability in photocatlaysis. As a result,
a vast majority of the research on photocatalysis has been done on
TiO<sub>2</sub>, which is chemically robust over a wide range of pH.
However, TiO<sub>2</sub> has a wide band gap (3.2 eV) and can only
absorb ∼4% of the solar spectrum, and thus, it will never provide
efficient solar energy conversion/storage on its own. Here, we report
photocatalytic CO<sub>2</sub> reduction with water to produce methanol
using TiO<sub>2</sub>-passivated GaP photocathodes under 532 nm wavelength
illumination. The TiO<sub>2</sub> layer prevents corrosion of the
GaP, as evidenced by atomic force microscopy and photoelectrochemical
measurements. Here, the GaP surface is passivated using a thin film
of TiO<sub>2</sub> deposited by atomic layer deposition (ALD), which
provides a viable, stable photocatalyst without sacrificing photocatalytic
efficiency. In addition to providing a stable photocatalytic surface,
the TiO<sub>2</sub> passivation provides substantial enhancement in
the photoconversion efficiency through passivation of surface states,
which cause nonradiative carrier recombination. In addition to passivation
effects, the TiO<sub>2</sub> deposited by ALD is n-type due to oxygen
vacancies and forms a pn-junction with the underlying p-type GaP photocathode.
This creates a built-in field that assists in the separation of photogenerated
electron–hole pairs, further reducing recombination. This reduction
in the surface recombination velocity (SRV) corresponds to a shift
in the overpotential of almost 0.5 V. No enhancement is observed for
TiO<sub>2</sub> thicknesses above 10 nm, due to the insulating nature
of the TiO<sub>2</sub>, which eventually outweighs the benefits of
passivation
Rational Design of a Green-Light-Mediated Unimolecular Platform for Fast Switchable Acidic Sensing
A controllable
sensing ability strongly connects to complex and
precise events in diagnosis and treatment. However, imposing visible
light into the molecular-scale mediation of sensing processes is restricted
by the lack of structural relevance. To address this critical challenge,
we present the rational design, synthesis, and in vitro studies of
a novel cyanostyryl-modified azulene system for green-light-mediated
fast switchable acidic sensing. The advantageous features of the design
include a highly efficient green-light-driven <i>Z/E</i>-isomerization (a quantum yield up to 61.3%) for fast erasing chromatic
and luminescent expressions and a superior compatibility with control
of ratiometric protonation. Significantly, these merits of the design
enable the development of a microfluidic system to perform a green-light-mediated
reusable sensing function toward a gastric acid analyte in a miniaturized
platform. The results may provide new insights for building future
integrated green materials
Concentrations and BCFs of (-)-PCB149/(+)-PCB149 in embryo-larvae when exposed to atropisomers.
<p>Concentrations and BCFs of (-)-PCB149/(+)-PCB149 in embryo-larvae when exposed to atropisomers.</p
Heatmap of the expression level of indicated genes relative to the no-addition control.
<p>Hierarchical clustering was performed and is represented graphically by a color gradient, where red represents the highest level of relative inhibition and green the highest level of relative activation.</p
Additional file 2: of Hypomethylation coordinates antagonistically with hypermethylation in cancer development: a case study of leukemia
List of C-DMRs. This is an “xls” file providing coordinates for hyper- and hypo-C-DMRs common across all control tests in separate excel sheets, respectively. (XLS 117 kb
Cirsium tanakae Matsum. forma obvallatum Makino
原著和名: クルマアザミ科名: キク科 = Compositae採集地: 千葉県 佐倉市 生谷 (下総 佐倉市 生谷)採集日: 1985/11/12採集者: 萩庭丈壽整理番号: JH030548国立科学博物館整理番号: TNS-VS-98054
The expression level of indicated genes relative to the no-addition control.
<p>A: transcription of genes involved in antioxidant system; B: transcription of genes involved in lipid-peroxidation; C: transcription of genes involved in methylation; D: transcription of CYP450; E: transcription of genes involved in dehydrogenation.</p
Zener Tunneling and Photocurrent Generation in Quasi-Metallic Carbon Nanotube pn-Devices
We investigate the electronic and
optoelectronic properties of
quasi-metallic nanotube pn-devices, which have smaller band gaps than
most known bulk semiconductors. These carbon nanotube-based devices
deviate from conventional bulk semiconductor device behavior due to
their low-dimensional nature. We observe rectifying behavior based
on Zener tunneling of ballistic carriers instead of ideal diode behavior,
as limited by the diffusive transport of carriers. We observe substantial
photocurrents at room temperature, suggesting that these quasi-metallic
pn-devices may have a broader impact in optoelectronic devices. A
new technique based on photocurrent spectroscopy is presented to identify
the unique chirality of nanotubes in a functional device. This chirality
information is crucial in obtaining a theoretical understanding of
the underlying device physics that depends sensitively on nanotube
chirality, as is the case for quasi-metallic nanotube devices. A detailed
model is developed to fit the observed <i>I–V</i> characteristics, which enables us to verify the band gap from these
measurements as well as the dimensions of the insulating tunneling
barrier region
Additional file 7: of Hypomethylation coordinates antagonistically with hypermethylation in cancer development: a case study of leukemia
WGCNA. This is a “docx” file that describes correlation modules in details, together with the step-by-step description of WGCNA analysis. WGCNA description includes data cleaning and preprocessing, adjacency topological overlap matrix construction, module detection, calculation of various module measures, and description of preservation statistics methods used. It includes tables and figures for both 3′UTR methylation and non-coding gene data, and their relation with expression of genes analysis. (DOCX 1555 kb
VIP-plot via PLS-DA on the expression level of indicated genes.
<p>A: differential genes through comparison of racemic and (+)- PCB149; B: differential genes through comparison of (-)- and (+)- PCB149.</p
- …