Effects of Low Suction Temperature on the Boil-off Gas compressor

The Boil-off Gas (BOG) compressor is used as a key facility in the liquefied natural gas (LNG) terminal, to recycle the excessive boiled gas for re-liquefaction or direct application. The low suction temperature down to -162? brings about big challenges in design of the BOG compressor. In this paper, the three-dimensional finite element model was used to simulate both the static and periodic transient temperature distribution in the cylinder of a BOG compressor, and a computational fluid dynamics (CFD) model was established to calculate the flow and heat transfer inside the compression chamber and suction/discharge pockets. A test rig was built up to validate the simulated results. The results showed that, the average temperatures in the suction and discharge pockets were about -109? and -60?, respectively, and the temperature of the compression chamber was in-between. The maximum temperature difference between outer and inner surface of the compressor cylinder reached up to 84? during start-up of the compressor, which yielded a thermal strain and stress in the cylinder much larger than those during steady operation of the compressor with only 31? of temperature difference. A variety of pre-cooling temperatures ranging from -20? to -60? were examined, and the results showed pre-cooling down to -20? before start-up was good enough. The amplitude of temperature fluctuation due to the periodic movement of the piston was less than 0.1? in the cylinder wall. The temperature coefficient tended to decrease at lower suction temperature. As the suction temperature decreased from -54.2?to -142.2?, the suction coefficient dropped drastically by 24.4%

Transplantation of fecal microbiota from APP/PS1 mice and Alzheimer’s disease patients enhanced endoplasmic reticulum stress in the cerebral cortex of wild-type mice

Background and purposeThe gut-brain axis is bidirectional and the imbalance of the gut microbiota usually coexists with brain diseases, including Alzheimer’s disease (AD). Accumulating evidence indicates that endoplasmic reticulum (ER) stress is a core lesion in AD and persistent ER stress promotes AD pathology and impairs cognition. However, whether the imbalance of the gut microbiota is involved in triggering the ER stress in the brain remains unknown.Materials and methodsIn the present study, fecal microbiota transplantation (FMT) was performed with gut microbiota from AD patients and APP/PS1 mice, respectively, resulting in two mouse models with dysregulated gut microbiota. The ER stress marker protein levels in the cerebral cortex were assessed using western blotting. The composition of the gut microbiota was assessed using 16S rRNA sequencing.ResultsExcessive ER stress was induced in the cerebral cortex of mice after FMT. Elevated ER stress marker proteins (p-perk/perk, p-eIF2α/eIF2α) were observed, which were rescued by 3,3-dimethyl-1-butanol (DMB). Notably, DMB is a compound that significantly attenuates serum trimethylamine-N-oxide (TMAO), a metabolite of the gut microbiota widely reported to affect cognition.ConclusionThe findings indicate that imbalance of the gut microbiota induces ER stress in the cerebral cortex, which may be mediated by TMAO

Graph Reinforcement Learning Application to Co-operative Decision-Making in Mixed Autonomy Traffic: Framework, Survey, and Challenges

Proper functioning of connected and automated vehicles (CAVs) is crucial for the safety and efficiency of future intelligent transport systems. Meanwhile, transitioning to fully autonomous driving requires a long period of mixed autonomy traffic, including both CAVs and human-driven vehicles. Thus, collaboration decision-making for CAVs is essential to generate appropriate driving behaviors to enhance the safety and efficiency of mixed autonomy traffic. In recent years, deep reinforcement learning (DRL) has been widely used in solving decision-making problems. However, the existing DRL-based methods have been mainly focused on solving the decision-making of a single CAV. Using the existing DRL-based methods in mixed autonomy traffic cannot accurately represent the mutual effects of vehicles and model dynamic traffic environments. To address these shortcomings, this article proposes a graph reinforcement learning (GRL) approach for multi-agent decision-making of CAVs in mixed autonomy traffic. First, a generic and modular GRL framework is designed. Then, a systematic review of DRL and GRL methods is presented, focusing on the problems addressed in recent research. Moreover, a comparative study on different GRL methods is further proposed based on the designed framework to verify the effectiveness of GRL methods. Results show that the GRL methods can well optimize the performance of multi-agent decision-making for CAVs in mixed autonomy traffic compared to the DRL methods. Finally, challenges and future research directions are summarized. This study can provide a valuable research reference for solving the multi-agent decision-making problems of CAVs in mixed autonomy traffic and can promote the implementation of GRL-based methods into intelligent transportation systems. The source code of our work can be found at https://github.com/Jacklinkk/Graph_CAVs.Comment: 22 pages, 7 figures, 10 tables. Currently under review at IEEE Transactions on Intelligent Transportation System

Suppression of <i>TREX1</i> deficiency-induced cellular senescence and interferonopathies by inhibition of DNA damage response

TREX1 encodes a major DNA exonuclease and mutations of this gene are associated with type I interferonopathies in human. Mice with Trex1 deletion or mutation have shortened life spans accompanied by a senescence-associated secretory phenotype. However, the contribution of cellular senescence in TREX1 deficiency-induced type I interferonopathies remains unknown. We found that features of cellular senescence present in Trex1−/− mice are induced by multiple factors, particularly DNA damage. The cGAS-STING and DNA damage response pathways are required for maintaining TREX1 deletion-induced cellular senescence. Inhibition of the DNA damage response, such as with Checkpoint kinase 2 (CHK2) inhibitor, partially alleviated progression of type I interferonopathies and lupus-like features in the mice. These data provide insights into the initiation and development of type I interferonopathies and lupus-like diseases, and may help inform the development of targeted therapeutics

Diterpenoids from the leaves of Casearia kurzii showing cytotoxic activities

A phytochemical investigation to obtain bioactive substances as lead compounds or agents for cancer led to the obtainment of six new and two known clerodane diterpenoids from the leaves of Casearia kurzii. Their structures were elucidated using NMR techniques and electronic circular dichroism (ECD) calculations. The subsequent biological cytotoxicity evaluation of these isolates toward human lung cancer A549, human cervical cancer HeLa, human chronic myeloid leukemia K562, and human hepatocellular carcinoma HepG2 was carried out. The most active compound 4 with an IC50 value of 9.7 μM against HepG2 cells was selected to examine the cytotoxic mechanism, which induced the apoptosis and arrested the HepG2 cell cycle at S stage. The in vivo zebrafish experiments revealed that compound 4 had the property of inhibiting tumor proliferation and migration.The National Key Research and Development Program of China, the National Natural Science Foundation of China, Hundred Young Academic Leaders Program of Nankai University, the Natural Science Foundation of Tianjin, State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources and the open project of Key Laboratory of Xinjiang Uygur Autonomous Region.http://www.elsevier.com/ locate/bmclhj2021Plant Production and Soil Scienc

Determining the Quantitative Threshold of High-Frequency Oscillation Distribution to Delineate the Epileptogenic Zone by Automated Detection

Objective: We proposed an improved automated high frequency oscillations (HFOs) detector that could not only be applied to various intracranial electrodes, but also automatically remove false HFOs caused by high-pass filtering. We proposed a continuous resection ratio of high order HFO channels and compared this ratio with each patient's post-surgical outcome, to determine the quantitative threshold of HFO distribution to delineate the epileptogenic zone (EZ).Methods: We enrolled a total of 43 patients diagnosed with refractory epilepsy. The patients were used to optimize the parameters for SEEG electrodes, to test the algorithm for identifying false HFOs, and to calculate the continuous resection ratio of high order HFO channels. The ratio can be used to determine a quantitative threshold to locate the epileptogenic zone.Results: Following optimization, the sensitivity, and specificity of our detector were 66.84 and 73.20% (ripples) and 69.76 and 66.13% (fast ripples, FRs), respectively. The sensitivity and specificity of our algorithm for removing false HFOs were 76.82 and 94.54% (ripples) and 72.55 and 94.87% (FRs), respectively. The median of the continuous resection ratio of high order HFO channels in patients with good surgical outcomes, was significantly higher than in patients with poor outcome, for both ripples and FRs (P &lt; 0.05 ripples and P &lt; 0.001 FRs).Conclusions: Our automated detector has the advantage of not only applying to various intracranial electrodes but also removing false HFOs. Based on the continuous resection ratio of high order HFO channels, we can set the quantitative threshold for locating epileptogenic zones

Integration Management and Reuse of Research Data in the Next Generation University IR Resources

[Purpose/Significance] In 2021, the Ministry of Education of China issued the "Norms for the Construction of Digital Campuses in Higher Education Institutions (Trial)", which mentioned that universities should attempt to form a new model of academic exchange and resource sharing through the construction of institutional repositories (IRs). The construction of knowledge resources in university IRs is gradually developing towards the next generation IRs. Research data resources are an important component of the future resources. From the perspective of the generation, acquisition, and existence of information resources in universities, the institutional resources in universities primarily consist of resources generated by "industry, academia, research and application" activities, including teaching resources, scientific research resources, design resources, scientific activity resources, etc., which are specifically reflected in the activity process such as scholar resources, research activity resources, research process resources, and research achievements resources. Research data resources are studied as the research object in this article. [Method/Process] This paper analyzes the formation mechanism of institutional knowledge resources, and conduct research on the integration, management and reuse of research data resources, including: 1) internal factors of research data, data generation, source, type, structure, and dependency mode; 2) research on external elements of data, such as data standards, unique identifiers, data registration, data protocols, data rights, data reuse, and data sharing Through the study of internal and external factors, the influencing factors, functions and roles, responsibilities and rights, permissions and attribution of data integration management and data reuse were sorted and interpreted and feasible methods were designed for research data management, collection, implementation, and registration. In order to ensure the effectiveness of data management, a series of standards and schemes have been developed, such as data type and format standards, metadata schemes, and data guardianship demand survey templates. The purpose is to achieve data discovery, interoperability, and reuse through continuous monitoring of scientific data. The basic rules of reuse are mainly divided into: 1) reuse: the concept of reuse, reuse, sharing, and incomplete equivalence in reuse; 2) sharing: possible to be used; 3) protocol usage: discussion about how to use it; and 4) rights use: complying with the data copyright agreement. [Results/Conclusions] Through research courses, the development and implementation of favorable data management and reuse strategies have clarified the data objects, management set management services, and data reuse permissions of research data in university IRs. We have clarified the current situation and urgent issues to integrate research data into the long-term preservation, management, and sharing and reuse system of knowledge resources in university IRs. We have defined the responsibilities, management mechanisms, standardized business processes, permission attributes, data exchange platforms, data registration, and data reuse of research data subjects by category, region, and field, and provided some suggestions and guarantee measures for the establishment of a data management center in China

Comparative Analysis of Nutritional Components of Wild Sea Cucumbers in Different Sea Areas

In order to provide reference for the comprehensive development and utilization, the nutritional function components of wild sea cucumbers in different sea areas were explored. This study comprehensively analyzed the nutritional composition of four wild sea cucumber species: Stichopus horrens, Stichopus chloronotus, Holothuria mammata, and Cucumaria frondosa. The basic nutritional composition, amino acid, fatty acid, and mineral element contents of the four sea cucumbers species were analyzed and evaluated. The results showed that the four species had high protein and low fat in common. Holothuria mammata exhibited the highest protein and lowest fat content. Stichopus chloronotus was rich in polysaccharides and ash content, while Cucumaria frondosa had notable saponin content. Each of the four sea cucumber types contained a consistent array of 17 amino acids, boasting substantial quantities of both delectable and medicinal amino acids. The essential amino acids accounted for a range of 13.78% to 20.27%, with Cucumaria frondosa displayed the most elevated content. Through the assessment of amino acid scores (AAS) and chemical scores (CS), lysine emerges was the predominant limiting amino acid across all four sea cucumber species. In terms of fatty acid composition, all species exhibited a spectrum of saturated fatty acids (SFA) within total fatty acids, with content varying from 23.84% to 36.24%. Palmitic acid (C16:0) and stearic acid (C18:0) constituted the primary components of this SFA makeup. Notably, polyunsaturated fatty acid (PUFA) content ranged from 56.39% to 72.93%, with Cucumaria frondosa displayed the highest proportion. Among the major elements, calcium (Ca) content was relatively higher in all four samples, except for Holothuria mammata. Among the trace elements, the highest content was iron (Fe). This comparative analysis showed that wild sea cucumbers in different sea areas were rich in various nutrients that the human body needs, and had different edible values and development utilization

The complete chloroplast genome of Myripnois dioica (Asteraceae)

Myripnois dioica (Asteraceae) is a dioecious shrub endemic to North China. In this study, its complete chloroplast genome sequence was assembled and characterized using Illumina paired-end sequencing technology. The whole genome was 153,793 bp in length, containing a pair of inverted repeat (IR) regions of 25,049 bp, a small single-copy (SSC) region of 18,683 bp, and a large single-copy (LSC) region of 85,012 bp. The genome encoded 134 genes including 89 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The overall GC content of the genome was 37.6%. Phylogenetic analysis based on maximum likelihood method indicated Myripnois dioica was close to the taxa in the genus Ligularia. Our results would benefit the conservation genetics and phylogenetic studies of this endemic species

Sensitive Glycoprotein Sandwich Assays by the Synergistic Effect of In Situ Generation of Raman Probes and Plasmonic Coupling of Ag Core–Au Satellite Nanostructures

Sensitive surface-enhanced Raman scattering (SERS) assays of glycoproteins have been proposed using <i>p</i>-aminothiophenol (PATP)-embedded Ag core–Au satellite nanostructures modified with <i>p</i>-mercaptophenylboronic acid (PMBA) and the self-assembled monolayer of PMBA on a smooth gold-coated wafer. The apparent Raman probe PATP on the surfaces of the Ag cores underwent a photodimerization to generate 4,4′-dimercaptoazobenzene (DMAB) in situ upon excitation of laser, and the in situ generated DMAB acted as the actual Raman probe with considerably strong SERS signals, which was further enhanced by the plasmonic coupling of the Ag core–Au satellite nanostructures due to the synergistic effect. The sandwich assays of glycoproteins showed high sensitivity and excellent selectivity against nonglycoproteins. The Ag core–Au satellite SERS nanostructures can be used for highly sensitive SERS assays of other analytes