110 research outputs found
Unfolding Drift Effects for Cosmic Rays over the Period of the Sun's Magnetic Field Reversal
A well-established, comprehensive 3-D numerical modulation model is applied
to simulate galactic protons, electrons and positrons from May 2011 to May
2015, including the solar magnetic polarity reversal of Solar Cycle 24. The
objective is to evaluate how these simulations compare with corresponding AMS
observations for 1.0-3.0 GV, and what underlying physics follows from this
comparison in order to improve our understanding on how the major physical
modulation processes change, especially particle drift, from a negative to a
positive magnetic polarity cycle. Apart from their local interstellar spectra,
electrons and positrons differ only in their drift patterns, but they differ
with protons in other ways such as their adiabatic energy changes at lower
rigidity. In order to complete the simulations for oppositely charged
particles, antiproton modeling results are obtained as well. Together, the
observations and the corresponding modeling indicate the difference in the
drift pattern before and after the recent polarity reversal and clarify to a
large extent the phenomenon of charge-sign dependence during this period. The
effect of global particle drift became negligible during this period of no
well-defined magnetic polarity. The resulting low values of all particles' MFPs
during the polarity reversal contrast their large values during solar minimum
activity, and as such expose the relative contributions and effects of the
different modulation processes from solar minimum to maximum activity. We find
that the drift scale starts recovering just after the polarity reversal, but
the MFPs keep decreasing or remain unchanged for some period after the polarity
reversal.Comment: Submitted to Astrophysical Journal, 27 pages, 13 Figure
Diagnosis of post-neurosurgical bacterial meningitis in patients with aneurysmal subarachnoid hemorrhage based on the immunity-related proteomics signature of the cerebrospinal fluid
IntroductionPost-neurosurgical bacterial meningitis (PNBM) is a serious complication for patients who receive neurosurgical treatment, but the diagnosis is difficult given the complicated microenvironment orchestrated by sterile brain injury and pathogenic infection. In this study, we explored potential diagnostic biomarkers and immunological features using a proteomics platform.MethodsA total of 31 patients with aneurysmal subarachnoid hemorrhage (aSAH) who received neurosurgical treatment were recruited for this study. Among them, 15 were diagnosed with PNBM. The remaining 16 patients were categorized into the non-PNBM group. Proteomics analysis of the cerebrospinal fluid (CSF) was conducted on the Olink platform, which contained 92 immunity-related molecules.ResultsWe found that the expressions of 27 CSF proteins were significantly different between the PNBM and non-PNBM groups. Of those 27 proteins, 15 proteins were upregulated and 12 were downregulated in the CSF of the PNBM group. The receiver operating characteristic curve analysis indicated that three proteins (pleiotrophin, CD27, and angiopoietin 1) had high diagnostic accuracy for PNBM. Furthermore, we also performed bioinformatics analysis to explore potential pathways and the subcellular localization of the proteins.ConclusionIn summary, we found a cohort of immunity-related molecules that can serve as potential diagnostic biomarkers for PNBM in patients with aSAH. These molecules also provide an immunological profile of PNBM
Pharmacokinetics of Mycophenolate Mofetil and Development of Limited Sampling Strategy in Early Kidney Transplant Recipients
The mycophenolate mofetil (MMF) dose management for optimization of post-transplant treatment especially the early postoperative phase has been well recognized. MMF is a pro-drug of mycophenolic acid (MPA) and is widely used in Chinese renal transplant patients. Until now, the pharmacokinetic (PK) characteristics and model for the area under the concentration–time curve for the 12-h (h) of exposure (AUC0-12h) of MPA (MPA-AUC0-12h) estimation were lacking for the new formulation of MMF dispersible tablet in renal transplant patients. The aims of the study were to investigate the PK characteristics of MMF dispersible tablet by detecting the active metabolite of MPA and to establish an accuracy and precision equation for calculating MPA-AUC0-12h by limited sampling strategy (LSS) in Chinese kidney transplant patients. A total of 60 postoperative kidney transplant recipients were given a multiple-dose of MMF dispersible tablet twice daily combination with tacrolimus (Tac) and steroids. On the 5th day post-transplantation, blood specimens were collected before drug administration and up to 12 h after MMF dispersible tablet administration. Non-compartmental PK analysis was used to determine the data obtained from individual patients. Multivariate stepwise regression analysis was used to develop models for predicting MPA-AUC0-12h. The 3- and 4-point sampling models using 2 h, 4 h, 8 h and 1 h, 2 h, 4 h and 8 h, respectively, allowed accurate estimation of MPA-AUC0-12h. PK parameters of MMF dispersible tablet were obtained and the 4-point LSS is the best model for accurate and precise estimation of MPA-AUC0-12h
GraphScope Flex: LEGO-like Graph Computing Stack
Graph computing has become increasingly crucial in processing large-scale
graph data, with numerous systems developed for this purpose. Two years ago, we
introduced GraphScope as a system addressing a wide array of graph computing
needs, including graph traversal, analytics, and learning in one system. Since
its inception, GraphScope has achieved significant technological advancements
and gained widespread adoption across various industries. However, one key
lesson from this journey has been understanding the limitations of a
"one-size-fits-all" approach, especially when dealing with the diversity of
programming interfaces, applications, and data storage formats in graph
computing. In response to these challenges, we present GraphScope Flex, the
next iteration of GraphScope. GraphScope Flex is designed to be both
resource-efficient and cost-effective, while also providing flexibility and
user-friendliness through its LEGO-like modularity. This paper explores the
architectural innovations and fundamental design principles of GraphScope Flex,
all of which are direct outcomes of the lessons learned during our ongoing
development process. We validate the adaptability and efficiency of GraphScope
Flex with extensive evaluations on synthetic and real-world datasets. The
results show that GraphScope Flex achieves 2.4X throughput and up to 55.7X
speedup over other systems on the LDBC Social Network and Graphalytics
benchmarks, respectively. Furthermore, GraphScope Flex accomplishes up to a
2,400X performance gain in real-world applications, demonstrating its
proficiency across a wide range of graph computing scenarios with increased
effectiveness
The Linked Data Benchmark Council (LDBC): Driving competition and collaboration in the graph data management space
Graph data management is instrumental for several use cases such as
recommendation, root cause analysis, financial fraud detection, and enterprise
knowledge representation. Efficiently supporting these use cases yields a
number of unique requirements, including the need for a concise query language
and graph-aware query optimization techniques. The goal of the Linked Data
Benchmark Council (LDBC) is to design a set of standard benchmarks that capture
representative categories of graph data management problems, making the
performance of systems comparable and facilitating competition among vendors.
LDBC also conducts research on graph schemas and graph query languages. This
paper introduces the LDBC organization and its work over the last decade
Vpr14-88-Apobec3G Fusion Protein Is Efficiently Incorporated into Vif-Positive HIV-1 Particles and Inhibits Viral Infection
APOBEC3G (A3G), a deoxycytidine deaminase, is a potent host antiviral factor that can restrict HIV-1 infection. During Vif-negative HIV-1 replication, A3G is incorporated into HIV-1 particles, induces mutations in reverse transcribed viral DNA and inhibits reverse transcription. However, HIV-1 Vif counteracts A3G's activities by inducing its degradation and by blocking its incorporation into HIV-1 particles. Thus, it is interesting to elucidate a mechanism that would allow A3G to escape the effects of Vif in order to rescue its potent antiviral activity and to provide a possible novel therapeutic strategy for treating HIV-1 infection.In this study, we generated an R88-A3G fusion protein by fusing A3G to a virion-targeting polypeptide (R14-88) derived from HIV-1 Vpr protein and compared its antiviral effects relative to those of HA-tagged native A3G (HA-A3G). Our study showed that transient expression of the R88-A3G fusion protein in both Vif(-) and Vif(+) HIV-1 producing cells drastically inhibited viral infection in HeLa-CD4-CCR5-cells, CD4(+) C8166 T cells and human primary PBMCs. Moreover, we established CD4(+) C8166 T cell lines that stably express either R88-A3G or HA-A3G by transduction with VSV-G-pseudotyped lentiviral vector that harbor expression cassettes for R88-A3G or HA-A3G, respectively, and tested their susceptibility to Vif(+) HIV-1 infection. Our results clearly reveal that expression of R88-A3G in transduced CD4(+) C8166 cells significantly blocked Vif(+) HIV-1 infection. In an attempt to understand the mechanism underlying the antiviral activity of R88-A3G, we demonstrated that R88-A3G was efficiently incorporated into viral particles in the presence of Vif. Moreover, PCR analysis revealed that R88-A3G significantly inhibited viral cDNA synthesis during the early stage of Vif(+) virus infection.Our results clearly indicate that R88 delivers A3G into Vif(+) HIV-1 particles and inhibits infectivity and spread of the virions among CD4(+) T cells. This study provides evidence for an effective strategy to modify a host protein with innate anti-HIV-1 activity and rescue its potent anti-HIV potential in the presence of Vif. Further characterization and optimization of this system may lead to the development of an effective therapeutic approach against HIV-1 infection
The Linked Data Benchmark Council (LDBC): Driving competition and collaboration in the graph data management space
Graph data management is instrumental for several use cases
such as recommendation, root cause analysis, financial fraud detection,
and enterprise knowledge representation. Efficiently supporting these use
cases yields a number of unique requirements, including the need for a
concise query language and graph-aware query optimization techniques.
The goal of the Linked Data Benchmark Council (LDBC) is to design
a set of standard benchmarks that capture representative categories of
graph data management problems, making the performance of systems
comparable and facilitating competition among vendors. LDBC also
conducts research on graph schemas and graph query languages. This
paper introduces the LDBC organization and its work over the last decade
Tensor products of higher almost split sequences in subcategories
summary:We introduce the algebras satisfying the condition. If , are algebras satisfying the , condition, respectively, we give a construction of -almost split sequences in some subcategories of by tensor products and mapping cones. Moreover, we prove that the tensor product algebra satisfies the condition for some integers , ; this construction unifies and extends the work of A. Pasquali (2017), (2019)
FATIGUE STRENGTH ANALYSIS AND OPTIMIZATION OF FSC RACING EXHAUST SYSTEM
The exhaust pipe of engine is subjected to alternating load of low and high temperatures during operation,which is prone to fatigue damage.For the FSC(Formula Student China) racing engine with the highest speed of 11 000 r/min~13 OOOr/min,the exhaust pipe fatigue problem is more serious.In this paper,the FSC racing exhaust system is taken as the research object to analyze its fatigue strength and optimize the exhaust pipe thickness.Firstly,the Fluent software is used to analyze the conjugate heat transfer of the exhaust system to determine the temperature distribution of the exhaust system.Then the temperature distribution is mapped to the finite element mesh of the exhaust system,and the thermal stress and thermal strain are analyzed by finite element technology.Subsequently,two schemes including exhaust manifold " normal operation-parking cooling" cycle and extreme working condition cycle are designed to carry out the thermal cycle simulation.It is found that the exhaust gas accumulates plastic deformation under the alternating load of each cycle,and the exhaust system will eventually crack and be destroyed.Finally,the fatigue life of the two schemes is studied by using Ansys nCode DesignLife fatigue analysis software.The results show that both schemes effectively reflect the life expectancy of low-cycle fatigue damages under the combined action of exhaust manifold temperature field,thermal stress and strain.Based on the above analysis,the exhaust thickness is optimized by the extreme working condition circulation scheme.and it is verified by experiments that the 1.2 mm thickness steel pipe meets the FSC exhaust requirements
Epoxy Resin Adhesives: Modification and Applications
Epoxy resin adhesives (ERAs) as easily prepared thermosetting adhesives have been extensively employed in building construction, electrical appliance manufacturing, automobile manufacturing and wood industry because of their excellent mechanical properties, water resistance, low cost, long service life and strong bonding properties. This chapter aims to introduce the synthesis, properties and development of ERAs and to illustrate how defects in their curing properties, thermal properties, brittleness and flammability affect their global development. Furthermore, this study introduces the modification of ERAs according to these defects and their development in main application fields. Lastly, the limitations and prospects of ERAs in future applications are also discussed
- …