9,089 research outputs found
(S)-Ethyl 2-[4-(6-chloroÂquinoxalin-2-ylÂoxy)phenÂoxy]propanoate
In the molÂecule of the title compound, C19H17ClN2O4, the quinoxaline ring system is planar [maximum deviation = 0.013 (3) Å] and oriented at a dihedral angle of 80.18 (3)° with respect to the benzene ring. In the crystal structure, interÂmolecular C—H⋯N interÂactions link molÂecules into chains. π–π contacts between the quinoxaline systems [centroid–centroid distance = 3.654 (1) Å] may further stabilize the structure
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Differential Features of Culprit Intracranial Atherosclerotic Lesions: A Whole-Brain Vessel Wall Imaging Study in Patients With Acute Ischemic Stroke.
BackgroundIntracranial atherosclerotic disease tends to affect multiple arterial segments. Using whole-brain vessel wall imaging, we sought to study the differences in plaque features among various types of plaques in patients with a recent unilateral anterior circulation ischemic stroke.Methods and resultsSixty-one patients with unilateral anterior circulation ischemic stroke were referred to undergo whole-brain vessel wall imaging (before and after contrast) within 1 month of symptom onset for intracranial atherosclerotic disease evaluations. Each plaque was classified as a culprit, probably culprit, or nonculprit lesion, according to its likelihood of causing the stroke. The associations between plaque features (thickening pattern, plaque-wall contrast ratio, high signal on T1-weighted images, plaque contrast enhancement ratio, enhancement grade, and enhancement pattern) and culprit lesions were estimated using mixed multivariable logistic regression after adjustment for maximum wall thickness. In 52 patients without motion corruption in whole-brain vessel wall imaging, a total of 178 intracranial plaques in the anterior circulation were identified, including 52 culprit lesions (29.2%), 51 probably culprit lesions (28.7%), and 75 nonculprit lesions (42.1%). High signal on T1-weighted images (adjusted odds ratio, 9.1; 95% confidence interval, 1.9-44.1; P=0.006), grade 2 (enhancement ratio of plaque ≥ enhancement ratio of pituitary) contrast enhancement (adjusted odds ratio, 17.4; 95% confidence interval, 1.8-164.9; P=0.013), and type 2 (≥50% cross-sectional wall involvement) enhancement pattern (adjusted odds ratio, 10.1; 95% confidence interval, 1.3-82.2; P=0.030) were independently associated with culprit lesions.ConclusionsHigh signal on T1-weighted images, grade 2 contrast enhancement, and type 2 enhancement pattern are associated with cerebrovascular ischemic events, which may provide valuable insights into risk stratification
Design and Synthesis Functional Selective Catalytic Reduction Catalyst for NOx Removal
AbstractMeOx-Cu-SSZ-13 (Me=Mn, Ce) was synthesized by physically mixing mental oxide and ion-exchanged zeolite. The composite catalyst showed highly efficient for the NOx removal using NH3-SCR method. And the NO conversion is 98% for MnOx-CeO2/Cu-SSZ-13 at 150°C and 97% for MnOx/Cu-SSZ-13 at 175°C. Meanwhile, the N2 selectivity remains more than 98%. The catalysts are characterized by using XRD and SEM. The XRD patterns show that all samples are highly crystallized and without impurities. The SEM demonstrates all samples have uniform crystal size. Composite catalyst especially combined with Cu-SSZ-13 has considerable potential as a catalyst in the area of NOx conversion
Refined Equivalent Pinhole Model for Large-scale 3D Reconstruction from Spaceborne CCD Imagery
In this study, we present a large-scale earth surface reconstruction pipeline
for linear-array charge-coupled device (CCD) satellite imagery. While
mainstream satellite image-based reconstruction approaches perform
exceptionally well, the rational functional model (RFM) is subject to several
limitations. For example, the RFM has no rigorous physical interpretation and
differs significantly from the pinhole imaging model; hence, it cannot be
directly applied to learning-based 3D reconstruction networks and to more novel
reconstruction pipelines in computer vision. Hence, in this study, we introduce
a method in which the RFM is equivalent to the pinhole camera model (PCM),
meaning that the internal and external parameters of the pinhole camera are
used instead of the rational polynomial coefficient parameters. We then derive
an error formula for this equivalent pinhole model for the first time,
demonstrating the influence of the image size on the accuracy of the
reconstruction. In addition, we propose a polynomial image refinement model
that minimizes equivalent errors via the least squares method. The experiments
were conducted using four image datasets: WHU-TLC, DFC2019, ISPRS-ZY3, and GF7.
The results demonstrated that the reconstruction accuracy was proportional to
the image size. Our polynomial image refinement model significantly enhanced
the accuracy and completeness of the reconstruction, and achieved more
significant improvements for larger-scale images.Comment: 24 page
Highly efficient in vitro adventitious shoot regeneration of Adenosma glutinosum (Linn.) Druce using leaf explants
Adenosma glutinosum (Linn.) Druce is an important aromatic plant, but no information is available regarding its regeneration, callus induction and proliferation from leaf explants. In this study, an in vitro shoot regeneration procedure was developed for native A. glutinosum using leaf explants. Callus induction and shoots regeneration from leaf explants was evaluated on Murashige and Skoog (MS) media supplemented with combinations of 6-benzylaminopurine (6-BA) and α-naphthaleneacetic acid (NAA). Callus induction in all 16 treatments exceeded 95%, and the highest adventitious shoot number per callus (7.22 shoots per explant) was obtained when leaf explants were cultured on MS medium supplemented with 0.5 mg• L-1 6-BA, 0.1 mg• L-1 NAA, 3% sucrose and 0.72% agar. The highest shoots strengthening were obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.3 mg• L-1 NAA, 3% sucrose, 1.0 g• L-1 active carbon and 0.72% agar. The highest total root number (45.2) and root length (43.3 cm) were obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.0 mg• L-1 NAA, 3% sucrose, 1.0 g L−1 active carbon and 0.72% agar, while the highest total root surface area (4.1 cm2) and total root volume (114.1 mm3) were obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.5 mg• L-1 NAA, 3% sucrose, 1.0 g• L-1 active carbon and 0.72% agar. The efficient plant regeneration system developed here will be helpful for rapid micropropagation and further genetic improvement in A. glutinosum. Keywords: Adenoma glutinous, plant growth regulator, plant regenerationAfrican Journal of Biotechnology Vol. 11(29), pp. 7542-7548, 10 April, 201
Sea Ice Extraction via Remote Sensed Imagery: Algorithms, Datasets, Applications and Challenges
The deep learning, which is a dominating technique in artificial
intelligence, has completely changed the image understanding over the past
decade. As a consequence, the sea ice extraction (SIE) problem has reached a
new era. We present a comprehensive review of four important aspects of SIE,
including algorithms, datasets, applications, and the future trends. Our review
focuses on researches published from 2016 to the present, with a specific focus
on deep learning-based approaches in the last five years. We divided all
relegated algorithms into 3 categories, including classical image segmentation
approach, machine learning-based approach and deep learning-based methods. We
reviewed the accessible ice datasets including SAR-based datasets, the
optical-based datasets and others. The applications are presented in 4 aspects
including climate research, navigation, geographic information systems (GIS)
production and others. It also provides insightful observations and inspiring
future research directions.Comment: 24 pages, 6 figure
Understanding the and charmonium(-like) states near 3.9 GeV
We propose that the observed in the channel is the
same state as the , and the , observed in the
channel, is an -wave hadronic molecule. In
addition, the {component in the } assigned to
the in the current {\it Review of Particle Physics} has the same
origin as the , which has a mass around 3.94~GeV. To check the
proposal, the available data in the and channels from
both decays and fusion reaction are analyzed considering
both the --- coupled
channels with and a state introduced additionally. It is
found that all the data in different processes can be simultaneously well
reproduced, and the coupled-channel dynamics produce four hidden-charm scalar
molecular states with masses around 3.73, 3.94, 3.99 and 4.23~GeV,
respectively. The results may deepen our understanding of the spectrum of
charmonia as well as of the interactions between charmed hadrons.Comment: 15 pages, 6 figures, 2 tables, to apear in Sci. Bul
Cyclin D2 plays a regulatory role in HBV replication
AbstractHepatitis B virus (HBV) infection is the leading cause of liver diseases. However, the molecular mechanisms of HBV infection and carcinogenesis have not been fully elucidated. In this study, we found that cyclin D2 was upregualted in HBV-expressing cells and liver tissues of HBV-transgenic mice. Gene silencing of cyclin D2 inhibited HBV DNA replicative intermediates, 3.5kb mRNA, core protein level, as well as the secretions of HBsAg and HBeAg. On the contrary, overexpression of cyclin D2 promoted HBV replication. Furthermore, cyclin D2 regulated HBV replication by enhancing the activity of HBV core and Sp1 promoters by targeting transcription factor CREB2. Silencing of CREB2 abolished enhancement of HBV replication induced by cyclin D2. Together, our study has uncovered a positive role of cyclin D2 in HBV replication. It is conceivable that therapeutic application of cyclin D2 inhibitor in HBV infection therapy
What Makes for Good Visual Instructions? Synthesizing Complex Visual Reasoning Instructions for Visual Instruction Tuning
Visual instruction tuning is an essential approach to improving the zero-shot
generalization capability of Multi-modal Large Language Models (MLLMs). A surge
of visual instruction datasets with various focuses and characteristics have
been proposed recently, enabling MLLMs to achieve surprising results on
evaluation benchmarks. To develop more capable MLLMs, in this paper, we aim to
investigate a more fundamental question: ``what makes for good visual
instructions?''. By conducting a comprehensive empirical study, we find that
instructions focused on complex visual reasoning tasks are particularly
effective in improving the performance of MLLMs on evaluation benchmarks.
Building upon this finding, we design a systematic approach to automatically
creating high-quality complex visual reasoning instructions. Our approach
employs a synthesis-complication-reformulation paradigm, leveraging multiple
stages to gradually increase the complexity of the instructions while
guaranteeing quality. Based on this approach, we create the synthetic visual
reasoning instruction dataset consisting of 32K examples, namely ComVint, and
fine-tune four MLLMs on it. Experimental results demonstrate that our dataset
consistently enhances the performance of all the compared MLLMs, e.g.,
improving the performance of MiniGPT-4 and BLIP-2 on MME-Cognition by 32.6% and
28.8%, respectively. Our code and data are publicly available at the link:
https://github.com/RUCAIBox/ComVint.Comment: Work in progres
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