51 research outputs found
Analysis of structural properties of Petri nets based on product incidence matrix
summary:This paper presents some structural properties of a generalized Petri net (PN) with an algorithm to determine the (partial) conservativeness and (partial) consistency of the net. A product incidence matrix or is defined and used to further improve the relations among PNs, linear inequalities and matrix analysis. Thus, based on Cramer's Rule, a new approach for the study of the solution of a linear system is given in terms of certain sub-determinants of the coefficient matrix and an efficient algorithm is proposed to compute these sub-determinants. The paper extends the common necessary and/or sufficient conditions for conservativeness and consistency in previous papers and some examples are designed to explain the conclusions finally
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Explorations with optically active, cage-annulated crown ethers.
A variety of optically active macrocyclic crown ethers that serve as "host" systems that are capable of differentiating between enantiomeric "guest" molecules during host-guest complexation have been prepared via incorporation of chiral elements into the crown ring skeleton. The ability of these crown ethers to recognize the enantiomers of guest salts, i.e., (+) a-methyl benzylamine and to transport them enantioselectively in W-tube transport experiments were studied. The ability of these crown ethers to perform as chiral catalysts in an enantioselective Michael addition was studied. The extent of asymmetric induction, expressed in terms of the enantiomeric excess (%ee), was monitored by measuring the optical rotation of the product and comparing to the literature value
Different responsiveness to a high-fat/cholesterol diet in two inbred mice and underlying genetic factors: a whole genome microarray analysis
<p>Abstract</p> <p>Background</p> <p>To investigate different responses to a high-fat/cholesterol diet and uncover their underlying genetic factors between C57BL/6J (B6) and DBA/2J (D2) inbred mice.</p> <p>Methods</p> <p>B6 and D2 mice were fed a high-fat/cholesterol diet for a series of time-points. Serum and bile lipid profiles, bile acid yields, hepatic apoptosis, gallstones and atherosclerosis formation were measured. Furthermore, a whole genome microarray was performed to screen hepatic genes expression profile. Quantitative real-time PCR, western blot and TUNEL assay were conducted to validate microarray data.</p> <p>Results</p> <p>After fed the high-fat/cholesterol diet, serum and bile total cholesterol, serum cholesterol esters, HDL cholesterol and Non-HDL cholesterol levels were altered in B6 but not significantly changed in D2; meanwhile, biliary bile acid was decreased in B6 but increased in D2. At the same time, hepatic apoptosis, gallstones and atherosclerotic lesions occurred in B6 but not in D2. The hepatic microarray analysis revealed distinctly different genes expression patterns between B6 and D2 mice. Their functional pathway groups included lipid metabolism, oxidative stress, immune/inflammation response and apoptosis. Quantitative real time PCR, TUNEL assay and western-blot results were consistent with microarray analysis.</p> <p>Conclusion</p> <p>Different genes expression patterns between B6 and D2 mice might provide a genetic basis for their distinctive responses to a high-fat/cholesterol diet, and give us an opportunity to identify novel pharmaceutical targets in related diseases in the future.</p
From Static to Dynamic: A Continual Learning Framework for Large Language Models
The vast number of parameters in large language models (LLMs) endows them
with remarkable capabilities, allowing them to excel in a variety of natural
language processing tasks. However, this complexity also presents challenges,
making LLMs difficult to train and inhibiting their ability to continuously
assimilate new knowledge, which may lead to inaccuracies in their outputs. To
mitigate these issues, this paper presents DynaMind, a novel continual learning
framework designed for LLMs. DynaMind incorporates memory mechanisms to
assimilate new knowledge and modular operators to enhance the model inference
process with the newly assimilated knowledge, consequently improving the
accuracies of LLMs' outputs. Benchmark experiments demonstrate DynaMind's
effectiveness in overcoming these challenges. The code and demo of DynaMind are
available on GitHub: https://github.com/Elfsong/DynaMind
VS-CAM: Vertex Semantic Class Activation Mapping to Interpret Vision Graph Neural Network
Graph convolutional neural network (GCN) has drawn increasing attention and
attained good performance in various computer vision tasks, however, there
lacks a clear interpretation of GCN's inner mechanism. For standard
convolutional neural networks (CNNs), class activation mapping (CAM) methods
are commonly used to visualize the connection between CNN's decision and image
region by generating a heatmap. Nonetheless, such heatmap usually exhibits
semantic-chaos when these CAMs are applied to GCN directly. In this paper, we
proposed a novel visualization method particularly applicable to GCN, Vertex
Semantic Class Activation Mapping (VS-CAM). VS-CAM includes two independent
pipelines to produce a set of semantic-probe maps and a semantic-base map,
respectively. Semantic-probe maps are used to detect the semantic information
from semantic-base map to aggregate a semantic-aware heatmap. Qualitative
results show that VS-CAM can obtain heatmaps where the highlighted regions
match the objects much more precisely than CNN-based CAM. The quantitative
evaluation further demonstrates the superiority of VS-CAM.Comment: 10 pages, 10 figure
Lingguizhugan decoction improves non-alcoholic steatohepatitis partially by modulating gut microbiota and correlated metabolites
BackgroundLingguizhugan decoction is a traditional Chinese medicine prescription that has been used to improve non-alcoholic fatty liver disease and its progressive form, non-alcoholic steatohepatitis (NASH). However, the anti-NASH effects and underlying mechanisms of Lingguizhugan decoction remain unclear.MethodsMale Sprague-Dawley rats were fed a methionine- and choline-deficient (MCD) diet to induce NASH, and then given Lingguizhugan decoction orally for four weeks. NASH indexes were evaluated by histopathological analysis and biochemical parameters including serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), liver triglycerides (TG), etc. Fecal samples of rats were subjected to profile the changes of gut microbiota and metabolites using 16S rRNA sequencing and ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS). Bioinformatics was used to identify Lingguizhugan decoction reversed candidates, and Spearman’s correlation analysis was performed to uncover the relationship among gut microbiota, fecal metabolites, and NASH indexes.ResultsFour-week Lingguizhugan decoction treatment ameliorated MCD diet-induced NASH features, as evidenced by improved hepatic steatosis and inflammation, as well as decreased serum AST and ALT levels. Besides, Lingguizhugan decoction partially restored the changes in gut microbial community composition in NASH rats. Meanwhile, the relative abundance of 26 genera was significantly changed in NASH rats, and 11 genera (such as odoribacter, Ruminococcus_1, Ruminococcaceae_UCG-004, etc.) were identified as significantly reversed by Lingguizhugan decoction. Additionally, a total of 99 metabolites were significantly altered in NASH rats, and 57 metabolites (such as TDCA, Glutamic acid, Isocaproic acid, etc.) enriched in different pathways were reversed by Lingguizhugan decoction. Furthermore, Spearman’s correlation analyses revealed that most of the 57 metabolites were significantly correlated with 11 genera and NASH indexes.ConclusionLingguizhugan decoction may exert protective effects on NASH partially by modulating gut microbiota and correlated metabolites
Disorder induced multifractal superconductivity in monolayer niobium dichalcogenides
The interplay between disorder and superconductivity is a subtle and
fascinating phenomenon in quantum many body physics. The conventional
superconductors are insensitive to dilute nonmagnetic impurities, known as the
Anderson's theorem. Destruction of superconductivity and even
superconductor-insulator transitions occur in the regime of strong disorder.
Hence disorder-enhanced superconductivity is rare and has only been observed in
some alloys or granular states. Because of the entanglement of various effects,
the mechanism of enhancement is still under debate. Here we report
well-controlled disorder effect in the recently discovered monolayer NbSe
superconductor. The superconducting transition temperatures of NbSe
monolayers are substantially increased by disorder. Realistic theoretical
modeling shows that the unusual enhancement possibly arises from the
multifractality of electron wave functions. This work provides the first
experimental evidence of the multifractal superconducting state
Solar Ring Mission: Building a Panorama of the Sun and Inner-heliosphere
Solar Ring (SOR) is a proposed space science mission to monitor and study the
Sun and inner heliosphere from a full 360{\deg} perspective in the ecliptic
plane. It will deploy three 120{\deg}-separated spacecraft on the 1-AU orbit.
The first spacecraft, S1, locates 30{\deg} upstream of the Earth, the second,
S2, 90{\deg} downstream, and the third, S3, completes the configuration. This
design with necessary science instruments, e.g., the Doppler-velocity and
vector magnetic field imager, wide-angle coronagraph, and in-situ instruments,
will allow us to establish many unprecedented capabilities: (1) provide
simultaneous Doppler-velocity observations of the whole solar surface to
understand the deep interior, (2) provide vector magnetograms of the whole
photosphere - the inner boundary of the solar atmosphere and heliosphere, (3)
provide the information of the whole lifetime evolution of solar featured
structures, and (4) provide the whole view of solar transients and space
weather in the inner heliosphere. With these capabilities, Solar Ring mission
aims to address outstanding questions about the origin of solar cycle, the
origin of solar eruptions and the origin of extreme space weather events. The
successful accomplishment of the mission will construct a panorama of the Sun
and inner-heliosphere, and therefore advance our understanding of the star and
the space environment that holds our life.Comment: 41 pages, 6 figures, 1 table, to be published in Advances in Space
Researc
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