204 research outputs found
UV/Ozone treatment to reduce metal-graphene contact resistance
We report reduced contact resistance of single-layer graphene devices by
using ultraviolet ozone (UVO) treatment to modify the metal/graphene contact
interface. The devices were fabricated from mechanically transferred, chemical
vapor deposition (CVD) grown, single layer graphene. UVO treatment of graphene
in the contact regions as defined by photolithography and prior to metal
deposition was found to reduce interface contamination originating from
incomplete removal of poly(methyl methacrylate) (PMMA) and photoresist. Our
control experiment shows that exposure times up to 10 minutes did not introduce
significant disorder in the graphene as characterized by Raman spectroscopy. By
using the described approach, contact resistance of less than 200 {\Omega}
{\mu}m was achieved, while not significantly altering the electrical properties
of the graphene channel region of devices.Comment: 17 pages, 5 figure
Up-regulation on cytochromes P450 in rat mediated by total alkaloid extract from Corydalis yanhusuo
BACKGROUND: Yanhusuo (Corydalis yanhusuo W.T. Wang; YHS), is a well-known traditional Chinese herbal medicine, has been used in China for treating pain including chest pain, epigastric pain, and dysmenorrhea. Its alkaloid ingredients including tetrahydropalmatine are reported to inhibit cytochromes P450 (CYPs) activity in vitro. The present study is aimed to assess the potential of total alkaloid extract (TAE) from YHS to effect the activity and mRNA levels of five cytochromes P450 (CYPs) in rat. METHODS: Rats were administered TAE from YHS (0, 6, 30, and 150 mg/kg, daily) for 14 days, alanine aminotransferase (ALT) levels in serum were assayed, and hematoxylin and eosin-stained sections of the liver were prepared for light microscopy. The effects of TAE on five CYPs activity and mRNA levels were quantitated by cocktail probe drugs using a rapid chromatography/tandem mass spectrometry (LC-MS/MS) method and reverse transcription-polymerase chain reaction (RT-PCR), respectively. RESULTS: In general, serum ALT levels showed no significant changes, and the histopathology appeared largely normal compared with that in the control rats. At 30 and 150 mg/kg TAE dosages, an increase in liver CYP2E1 and CYP3A1 enzyme activity were observed. Moreover, the mRNA levels of CYP2E1 and CYP3A1 in the rat liver, lung, and intestine were significantly up-regulated with TAE from 6 and 30 mg/kg, respectively. Furthermore, treatment with TAE (150 mg/kg) enhanced the activities and the mRNA levels of CYP1A2 and CYP2C11 in rats. However, the activity or mRNA level of CYP2D1 remained unchanged. CONCLUSIONS: These results suggest that TAE-induced CYPs activity in the rat liver results from the elevated mRNA levels of CYPs. Co-administration of prescriptions containing YHS should consider a potential herb (drug)–drug interaction mediated by the induction of CYP2E1 and CYP3A1 enzymes
Evaluation on substitution of energy transition—An empirical analysis based on factor elasticity
The study explores into the dynamic change features and technological differences in substitution between factors and energy sources for various types of China’s technological progresses from 1990 to 2020. The measurement for such a study is conducted from the perspective of factor substitution by employing the transcendental logarithmic production function. The results reveal that the sources of contribution to China’s economic development are mainly attributed to non-energy factors such as capital and labor, as capital and labor can effectively substitute energy, and non-fossil energy sources possess certain comparative advantages over fossil energy sources in terms of technology within energy factors. With such an increase in substitution, the trend of clean energy substitution for fossil energy is irreversible. Accordingly, it is proposed that the path for energy conservation and consumption reduction via energy transformation be achieved by increasing input into capital and labor to improve the utilization efficiency of these two factors from the perspective of factor substitution. Meanwhile, preferences should be delivered for the development of non-fossil energy sources in terms of technology bias and input scale
Visual Analytics for Efficient Image Exploration and User-Guided Image Captioning
Recent advancements in pre-trained large-scale language-image models have
ushered in a new era of visual comprehension, offering a significant leap
forward. These breakthroughs have proven particularly instrumental in
addressing long-standing challenges that were previously daunting. Leveraging
these innovative techniques, this paper tackles two well-known issues within
the realm of visual analytics: (1) the efficient exploration of large-scale
image datasets and identification of potential data biases within them; (2) the
evaluation of image captions and steering of their generation process. On the
one hand, by visually examining the captions automatically generated from
language-image models for an image dataset, we gain deeper insights into the
semantic underpinnings of the visual contents, unearthing data biases that may
be entrenched within the dataset. On the other hand, by depicting the
association between visual contents and textual captions, we expose the
weaknesses of pre-trained language-image models in their captioning capability
and propose an interactive interface to steer caption generation. The two parts
have been coalesced into a coordinated visual analytics system, fostering
mutual enrichment of visual and textual elements. We validate the effectiveness
of the system with domain practitioners through concrete case studies with
large-scale image datasets
A cross-species alignment tool (CAT)
<p>Abstract</p> <p>Background</p> <p>The main two sorts of automatic gene annotation frameworks are <it>ab initio </it>and alignment-based, the latter splitting into two sub-groups. The first group is used for intra-species alignments, among which are successful ones with high specificity and speed. The other group contains more sensitive methods which are usually applied in aligning inter-species sequences.</p> <p>Results</p> <p>Here we present a new algorithm called <it>CAT </it>(for Cross-species Alignment Tool). It is designed to align mRNA sequences to mammalian-sized genomes. <it>CAT </it>is implemented using C scripts and is freely available on the web at <url>http://xat.sourceforge.net/</url>.</p> <p>Conclusions</p> <p>Examined from different angles, <it>CAT </it>outperforms other extant alignment tools. Tested against all available mouse-human and zebrafish-human orthologs, we demonstrate that <it>CAT </it>combines the specificity and speed of the best intra-species algorithms, like <it>BLAT </it>and <it>sim4</it>, with the sensitivity of the best inter-species tools, like <it>GeneWise</it>.</p
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