111 research outputs found
Robust Optimization of Fourth Party Logistics Network Design under Disruptions
The Fourth Party Logistics (4PL) network faces disruptions of various sorts under the dynamic and complex environment. In order to explore the robustness of the network, the 4PL network design with consideration of random disruptions is studied. The purpose of the research is to construct a 4PL network that can provide satisfactory service to customers at a lower cost when disruptions strike. Based on the definition of β-robustness, a robust optimization model of 4PL network design under disruptions is established. Based on the NP-hard characteristic of the problem, the artificial fish swarm algorithm (AFSA) and the genetic algorithm (GA) are developed. The effectiveness of the algorithms is tested and compared by simulation examples. By comparing the optimal solutions of the 4PL network for different robustness level, it is indicated that the robust optimization model can evade the market risks effectively and save the cost in the maximum limit when it is applied to 4PL network design
Chemistry of new particle formation and growth events during wintertime in suburban area of Beijing : Insights from highly polluted atmosphere
The high frequency of new particle formation (NPF) events observed under polluted atmospheric conditions is still poorly understood. To improve our understanding of NPF and its effects, the particle number size distribution (3-1000 nm) and submicron particle chemical composition were measured from 4 November 2017 to 17 January 2018 in suburban Beijing. During this intense campaign, 22 NPF events were identified with a frequency of 29%, including 11 cases that occurred under "clean" conditions (C-NPF) and 11 cases that occurred under "polluted" conditions (P-NPF). The observed formation rate (J(3)) and condensation sink were 4.6-148.9 cm(-3).s(-1) and 0.01-0.07 s(-1), and the majority of NPF events occurred when the condensation sink (CS) values below 0.03 s(-1), indicating that condensation vapor likely constitutes the critical limiting factor for NPF events. The correlations between log J(3) and [H2SO4] that close to previous CLOUD experimental results in the majority of NPF events (68%) suggest the high nucleation rates (up to 100 cm(-3).s(-1)) would be attributed by the amines that enhancing sulfuric acid nucleation, while the reminding cases (32%) possibly attributed to the H2SO4-NH3 clustering mechanism, which is supported by the theoretical expectations for H2SO4 nucleation with NH3 simulated by the MALTE_BOX model. The observed growth rate varied from 4.9 to 37.0 mm.h(-1), with the dominant contribution (>60%) from sulfuric acid during the early phases of growth (similar to 4 nm), which was also sufficient to explain the observed Q(GR) for 50 nm)Peer reviewe
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Composition and protein precipitation capacity of condensed tannins in purple prairie clover (Dalea purpurea Vent.)
The objectives of this study were to determine the concentration and composition of condensed tannins (CT) in different tissues of purple prairie clover (PPC; Dalea purpurea Vent.) at different maturities and to determine their protein-precipitating capacity. The compositions of CT were elucidated after thiolysis with benzyl mercaptan followed by high-performance liquid chromatography and 1H−13C HSQC NMR spectroscopy. Results indicated that PPC flowering heads contained the highest CT concentration. Purple prairie clover CT consisted mainly of epicatechin (EC) and epigallocatechin (EGC) subunits. Condensed tannins in leaves were composed of more EC and less EGC than CT in stems and flowering heads at both early flowering and late flowering head stages. The mean degree of polymerization was the highest for CT in stems and increased with maturity. Condensed tannins isolated from PPC leaves at the early flowering head stage exhibited the greatest biological activity in terms of protein precipitation. Overall, condensed tannins in PPC were predominantly procyanidins and the concentration and composition varied among plant tissues and with maturity
Gu-4 Suppresses Affinity and Avidity Modulation of CD11b and Improves the Outcome of Mice with Endotoxemia and Sepsis
BACKGROUND: Systemic leukocyte activation and disseminated leukocyte adhesion will impair the microcirculation and cause severe decrements in tissue perfusion and organ function in the process of severe sepsis. Gu-4, a lactosyl derivative, could selectively target CD11b to exert therapeutic effect in a rat model of severe burn shock. Here, we addressed whether Gu-4 could render protective effects on septic animals. METHODOLOGY/PRINCIPAL FINDINGS: On a murine model of endotoxemia induced by lipopolysaccharide (LPS), we found that the median effective dose (ED50) of Gu-4 was 0.929 mg/kg. In vivo treatment of Gu-4 after LPS challenge prominently attenuated LPS-induced lung injury and decreased lactic acid level in lung tissue. Using the ED50 of Gu-4, we also demonstrated that Gu-4 treatment significantly improved the survival rate of animals underwent sepsis induced by cecal ligation and puncture. By adhesion and transwell migration assays, we found that Gu-4 treatment inhibited the adhesion and transendothelial migration of LPS-stimulated THP-1 cells. By flow cytometry and microscopy, we demonstrated that Gu-4 treatment inhibited the exposure of active I-domain and the cluster formation of CD11b on the LPS-stimulated polymorphonuclear leukocytes. Western blot analyses further revealed that Gu-4 treatment markedly inhibited the activation of spleen tyrosine kinase in LPS-stimulated THP-1 cells. CONCLUSIONS/SIGNIFICANCE: Gu-4 improves the survival of mice underwent endotoxemia and sepsis, our in vitro investigations indicate that the possible underlying mechanism might involve the modulations of the affinity and avidity of CD11b on the leukocyte. Our findings shed light on the potential use of Gu-4, an interacting compound to CD11b, in the treatment of sepsis and septic shock
The LARGE Principle of Cellular Reprogramming: Lost, Acquired and Retained Gene Expression in Foreskin and Amniotic Fluid-Derived Human iPS Cells
Human amniotic fluid cells (AFCs) are routinely obtained for prenatal diagnostics procedures. Recently, it has been illustrated that these cells may also serve as a valuable model system to study developmental processes and for application in regenerative therapies. Cellular reprogramming is a means of assigning greater value to primary AFCs by inducing self-renewal and pluripotency and, thus, bypassing senescence. Here, we report the generation and characterization of human amniotic fluid-derived induced pluripotent stem cells (AFiPSCs) and demonstrate their ability to differentiate into the trophoblast lineage after stimulation with BMP2/BMP4. We further carried out comparative transcriptome analyses of primary human AFCs, AFiPSCs, fibroblast-derived iPSCs (FiPSCs) and embryonic stem cells (ESCs). This revealed that the expression of key senescence-associated genes are down-regulated upon the induction of pluripotency in primary AFCs (AFiPSCs). By defining distinct and overlapping gene expression patterns and deriving the LARGE (Lost, Acquired and Retained Gene Expression) Principle of Cellular Reprogramming, we could further highlight that AFiPSCs, FiPSCs and ESCs share a core self-renewal gene regulatory network driven by OCT4, SOX2 and NANOG. Nevertheless, these cell types are marked by distinct gene expression signatures. For example, expression of the transcription factors, SIX6, EGR2, PKNOX2, HOXD4, HOXD10, DLX5 and RAXL1, known to regulate developmental processes, are retained in AFiPSCs and FiPSCs. Surprisingly, expression of the self-renewal-associated gene PRDM14 or the developmental processes-regulating genes WNT3A and GSC are restricted to ESCs. Implications of this, with respect to the stability of the undifferentiated state and long-term differentiation potential of iPSCs, warrant further studies
MicroRNAs Differentially Expressed in Postnatal Aortic Development Downregulate Elastin via 3′ UTR and Coding-Sequence Binding Sites
Elastin production is characteristically turned off during the maturation of elastin-rich organs such as the aorta. MicroRNAs (miRNAs) are small regulatory RNAs that down-regulate target mRNAs by binding to miRNA regulatory elements (MREs) typically located in the 3′ UTR. Here we show a striking up-regulation of miR-29 and miR-15 family miRNAs during murine aortic development with commensurate down-regulation of targets including elastin and other extracellular matrix (ECM) genes. There were a total of 14 MREs for miR-29 in the coding sequences (CDS) and 3′ UTR of elastin, which was highly significant, and up to 22 miR-29 MREs were found in the CDS of multiple ECM genes including several collagens. This overrepresentation was conserved throughout mammalian evolution. Luciferase reporter assays showed synergistic effects of miR-29 and miR-15 family miRNAs on 3′ UTR and coding-sequence elastin constructs. Our results demonstrate that multiple miR-29 and miR-15 family MREs are characteristic for some ECM genes and suggest that miR-29 and miR-15 family miRNAs are involved in the down-regulation of elastin in the adult aorta
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Replication materials for Empirical Study on Causes of Happiness Based on Panel Data of General Social Survey
Routing optimization of fourth party logistics with reliability constraints based on Messy GA
Purpose: The purpose of this paper is to choose a optimal routing in fourth party logistics
(4PL) with the objective of transportation cost minimization under reliability level constraint.
Design/methodology/approach: Reliability theory is applied to routing optimization
problem. A mathematical model of the 4PL routing optimization problem with reliability
constraints is built, which aims to find a route at the minimum cost. Due to the 4PL routing
problem is NP-hard, two algorithms are designed: Messy Genetic Algorithm (Messy GA) and
Enumeration Algorithm (EA).
Findings: Through the model and algorithm, 4PL company can obtain the optimal solution
quickly and effectively, according to customer’s reliability requirements.
Practical implications: We give an example for test the effectiveness of the method and the
algorithm.
Originality/value: In this paper, we put objective factors that cause disturbances of
transportation time into consideration, and reliability theory is applied to 4PL routing
optimization problem. A Messy GA with double arrays encoding method is designed to solve
the problem
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