787 research outputs found

    Dynamic Analysis and Optimization of a Production Control System under Supply and Demand Uncertainties

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    This study investigates the dynamic performance and optimization of a typical discrete production control system under supply disruption and demand uncertainty. Two different types of uncertain demands, disrupted demand with a step change in demand and random demand, are considered. We find that, under demand disruption, the system’s dynamic performance indicators (the peak values of the order rate, production completion rate, and inventory) increase with the duration of supply disruption; however, they increase and decrease sequentially with the supply disruption start time. This change tendency differs from the finding that each kind of peak is independent of the supply disruption start time under no demand disruption. We also find that, under random demand, the dynamic performance indicators (Bullwhip and variance amplification of inventory relative to demand) increase with the disruption duration, but they have a decreasing tendency as demand variance increases. In order to design an adaptive system, we propose a genetic algorithm that minimizes the respective objective function on the system’s dynamic performance indicators via choosing appropriate system parameters. It is shown that the optimal parameter choices relate closely to the supply disruption start time and duration under disrupted demand and to the supply disruption duration under random demand

    QED effects on phase transition and Ruppeiner geometry of Euler-Heisenberg-AdS black holes

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    Taking the quantum electrodynamics (QED) effect into account, we study the black hole phase transition and Ruppeiner geometry for the Euler-Heisenberg anti-de Sitter black hole in the extended phase space. For negative and small positive QED parameter, we observe a small/large black hole phase transition and reentrant phase transition, respectively. While a large positive value of the QED parameter ruins the phase transition. The phase diagrams for each case are explicitly exhibited. Then we construct the Ruppeiner geometry in the thermodynamic parameter space. Different features of the corresponding scalar curvature are shown for both the small/large black hole phase transition and reentrant phase transition cases. Of particular interest is that an additional region of positive scalar curvature indicating dominated repulsive interaction among black hole microstructure is present for the black hole with a small positive QED parameter. Furthermore, the universal critical phenomena are also observed for the scalar curvature of the Ruppeiner geometry. These results indicate that the QED parameter has a crucial influence on the black hole phase transition and microstructure.Comment: 19 pages, 14 figure

    Određivanje sastava petroletarskog ekstrakta droge Maydis stigma primenom GC-MS

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    In this paper, the results of the chemical composition investigations of light- petroleum extract of crude herbal drug Maydis stigma by means of GC-MS. were presented. Analysis of saponifiables resulted in identification of 15 fatty acids, with octadecanoic acid as the most prominent one (17,3 %). Eicosanoic and octadecadienoic acids (16,0 and 10,7 %, respectively) were also present in significant concentration Analysis of non-saponifiables resulted in identification of 20 compounds. Non-saponifiable matter of Maydis stigma light-petroleum extract is characterized by high percentage of n-alkanes (53,0 %) and phytosterols (37,4 %), while the rest is composed mainly of triterpenes (a-amyrine and friedelin), as well as the carotenoids. The principal constituents of non-saponifiable matter fraction were identified as p-sitosterol (23 %) and alkane C29H60 (15,1 %).U ovom radu, prikazani su rezultati ispitivanja hemijskog sastava petroletarskog ekstrakta droge Maydis stigma primenom GC-MS. Analizom frakcije saponifikovanih materija, identifikovano je 15 masnih kiselina. Glavni sastojak je oktadekanska kiselina, koja čini 17,3 % ispitivane smese. Značajno su zastupljene eikozanska i oktadekadienska kiselina, koje čine 16,0 odnosno 10,7 % ispitivane frakcije. Analizom nesaponifikovanih materija, identifikovano je 20 komponenata. Nesaponifikovane materije petroletarskog ekstrakta droge Maydis stigma karakteriše visok sadržaj n-alkana (53,0 %) i fitosterola (37,4 %), dok ostatak čine triterpeni (a-amirin i fridelin) i karotenoidi. Glavni sastojak frakcije fitosterola je p-sitosterol (23 %), dok je među ugljovodonicima dominantan alkan C29H60 (15,1 %)

    Flow Cytometry and K-mer Analysis Estimates of the Genome Sizes of \u3cem\u3eBemisia tabaci\u3c/em\u3e B and Q (Hemiptera: Aleyrodidae)

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    The genome sizes of the B- and Q-types of the whitefly Bemisia tabaci (Gennnadius) were estimated using flow cytometry (Drosophila melanogaster as the DNA reference standard and propidium iodide (PI) as the fluorochrome) and k-mer analysis. For flow cytometry, the mean nuclear DNA content was 0.686 pg for B-type males, 1.392 pg for B-type females, 0.680 pg for Q-type males, and 1.306 pg for Q-type females. Based on the relationship between DNA content and genome size (1 pg DNA = 980 Mbp), the haploid genome size of B. tabaci ranged from 640 to 682 Mbp. For k-mer analysis, genome size of B-type by two methods were consistent highly, but the k-mer depth distribution graph of Q-type was not enough perfect and the genome size was estimated about 60 M larger than its flow cytometry result. These results corroborate previous reports of genome size based on karyotype analysis and chromosome counting. However, these estimates differ from previous flow cytometry estimates, probably because of differences in the DNA reference standard and dyeing time, which were superior in the current study. For Q-type genome size difference by two method, some discussion were also stated, and all these results represent a useful foundation for B. tabaci genomics research

    Heat Shock Protein 70 Protects the Heart from Ischemia/Reperfusion Injury through Inhibition of p38 MAPK Signaling.

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    BackgroundHeat shock protein 70 (Hsp70) has been shown to exert cardioprotection. Intracellular calcium ([Ca2+]i) overload induced by p38 mitogen-activated protein kinase (p38 MAPK) activation contributes to cardiac ischemia/reperfusion (I/R) injury. However, whether Hsp70 interacts with p38 MAPK signaling is unclear. Therefore, this study investigated the regulation of p38 MAPK by Hsp70 in I/R-induced cardiac injury.MethodsNeonatal rat cardiomyocytes were subjected to oxygen-glucose deprivation for 6 h followed by 2 h reoxygenation (OGD/R), and rats underwent left anterior artery ligation for 30 min followed by 30 min of reperfusion. The p38 MAPK inhibitor (SB203580), Hsp70 inhibitor (Quercetin), and Hsp70 short hairpin RNA (shRNA) were used prior to OGD/R or I/R. Cell viability, lactate dehydrogenase (LDH) release, serum cardiac troponin I (cTnI), [Ca2+]i levels, cell apoptosis, myocardial infarct size, mRNA level of IL-1β and IL-6, and protein expression of Hsp70, phosphorylated p38 MAPK (p-p38 MAPK), sarcoplasmic/endoplasmic reticulum Ca2+-ATPase2 (SERCA2), phosphorylated signal transducer and activator of transcription3 (p-STAT3), and cleaved caspase3 were assessed.ResultsPretreatment with a p38 MAPK inhibitor, SB203580, significantly attenuated OGD/R-induced cell injury or I/R-induced myocardial injury, as evidenced by improved cell viability and lower LDH release, resulted in lower serum cTnI and myocardial infarct size, alleviation of [Ca2+]i overload and cell apoptosis, inhibition of IL-1β and IL-6, and modulation of protein expressions of p-p38 MAPK, SERCA2, p-STAT3, and cleaved-caspase3. Knockdown of Hsp70 by shRNA exacerbated OGD/R-induced cell injury, which was effectively abolished by SB203580. Moreover, inhibition of Hsp70 by quercetin enhanced I/R-induced myocardial injury, while SB203580 pretreatment reversed the harmful effects caused by quercetin.ConclusionsInhibition of Hsp70 aggravates [Ca2+]i overload, inflammation, and apoptosis through regulating p38 MAPK signaling during cardiac I/R injury, which may help provide novel insight into cardioprotective strategies
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