3,718 research outputs found

    Integrated optimisation for production capacity, raw material ordering and production planning under time and quantity uncertainties based on two case studies

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    Abstract This paper develops a supply chain (SC) model by integrating raw material ordering and production planning, and production capacity decisions based upon two case studies in manufacturing firms. Multiple types of uncertainties are considered; including: time-related uncertainty (that exists in lead-time and delay) and quantity-related uncertainty (that exists in information and material flows). The SC model consists of several sub-models, which are first formulated mathematically. Simulation (simulation-based stochastic approximation) and genetic algorithm tools are then developed to evaluate several non-parameterised strategies and optimise two parameterised strategies. Experiments are conducted to contrast these strategies, quantify their relative performance, and illustrate the value of information and the impact of uncertainties. These case studies provide useful insights into understanding to what degree the integrated planning model including production capacity decisions could benefit economically in different scenarios, which types of data should be shared, and how these data could be utilised to achieve a better SC system. This study provides insights for small and middle-sized firm management to make better decisions regarding production capacity issues with respect to external uncertainty and/or disruptions; e.g. trade wars and pandemics.</jats:p

    A Literature Review of Seaport Decarbonisation: Solution Measures and Roadmap to Net Zero

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    This paper provides a comprehensive review of the literature related to seaport decarbonisation by combining the academic literature with case studies, industrial reports, newsletters, and domain knowledge. Through the literature review, the emission sources at seaports are categorised according to different criteria for better understanding. One of the criteria is the geographic location, which divides the emission sources into four categories. For each emission source category, the emission reduction measures in the literature are categorised into six structured categories including operational measures, technical measures, fuel and energy measures, infrastructural measures, digitalisation measures, and policy and collaboration measures. The first three categories have a direct impact on emission reductions, whereas the last three categories tend to support and facilitate the development and implementation of the first three categories. Representative case studies are selected from the UK ports to discuss their decarbonisation practices and pathways to net zero. We then propose a generic time-phased roadmap for port decarbonisation towards net zero, which divides the solution measures in each category into three phases to show their progressive processes. We explain the dependence relationships of the solution measures in the roadmap and discuss the challenges and opportunities in the implementation of the roadmap. This paper could offer strategic guidelines to port-associated stakeholders to implement emission reduction strategies and transition to net zero from the system perspective.</jats:p

    Ocean container transport in global supply chains: Overview and research opportunities

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    This paper surveys the extant research in the field of ocean container transport. A wide range of issues is discussed including strategic planning, tactical planning and operations management issues, which are categorized into six research areas. The relationships be- tween these research areas are discussed and the relevant literature is reviewed. Representative models are selected or modified to provide a flavour of their functions and application context, and used to explain current shipping practices. Future research opportunities bearing in mind the emerging phenomena in the field are discussed. The main purpose is to raise awareness and encourage more research into and application of operations management techniques and tools in container transport chains

    A Performance Analysis Model of TCP over Multiple Heterogeneous Paths for 5G Mobile Services

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    Driven by the primary requirement of emerging 5G mobile services, the demand for concurrent multipath transfer (CMT) is still prominent. Yet, multipath transport protocols are not widely adopted and TCP-based CMT schemes will still be in dominant position in 5G. However, the performance of TCP flow transferred over multiple heterogeneous paths is prone to the link quality asymmetry, the extent of which was revealed to be significant by our field investigation. In this paper, we present a performance analysis model for TCP over multiple heterogeneous paths in 5G scenarios, where both bandwidth and delay asymmetry are taken into consideration. The evaluation adopting parameters from field investigation shows that the proposed model can achieve high accuracy in practical environments. Some interesting inferences can be drawn from the proposed model, such as the dominant factor that affect the performance of TCP over heterogeneous networks, and the criteria of determining the appropriate number of links to be used under different circumstances of path heterogeneity. Thus, the proposed model can provide a guidance to the design of TCP-based CMT solutions for 5G mobile services

    Enhanced expression of radish-specific proteins in a disomic rapeseed-radish chromosome addition line resistant to root-knot nematodes

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    Wurzelgallennematoden sind weltweit fĂŒr ganz erheb­liche Ertrags- und QualitĂ€tseinbußen verantwortlich. FĂŒr den tropischen und subtropischen Teil Chinas sind ins­besondere Meloidogyne incognita und M. javanica von Bedeu­tung. Die disome Additionslinie ee einer kompletten Serie von Raps-Rettich-Additionslinien hatte sich in vorherigen Versuchen als resistent gegenĂŒber diesen beiden Nematodenarten erwiesen. Das Proteinmuster dieser disomen Additionslinie wurde mittels zweidimensionaler Gelelektrophorese und Image Master 5.0 Software mit dem des Rettich-Donors und dem des Raps-Rezipienten verglichen. Differentiell exprimierte Proteine wurden mittels MALDI-TOF-TOF/MS identifiziert. Drei Rettich-spezifische Proteine, die eine erhöhte Expression in der Additionslinie ee aufwiesen, sollen in einem zweiten Schritt auf eine potentielle Funktion im Resistenzmechanismus untersucht werden.Root-knot nematodes cause significant economic losses worldwide each year. Species with especially high relevance in the tropical and subtropical part of China are Meloidogyne incognita and M. javanica. The disomic rapeseed-radish chromosome addition line ee was shown in former experiments to be highly resistant against these southern root-knot nematodes. In this study, differen­tially expressed proteins in the roots of the addition line ee, its radish donor line and its rapeseed recipient line cv. Madora were screened by two-dimensional gel electrophoresis and Image Master 5.0 software. These proteins were identified by MALDI-TOF-TOF/MS. Three radish-specific proteins with an increased expression in rapeseed-radish addition line ee will be further analyzed for their potential role in nematode resistance

    Effects of caffeine, tea polyphenol and daidzein on the pharmacokinetics of lansoprazole and its metabolites in rats

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    O objetivo deste estudo foi avaliar os efeitos da cafeĂ­na, do polifenol do chĂĄ e da daidzeĂ­na na farmacocinĂ©tica do lansoprazol e de seus metabĂłlitos. Administraram-se, intragastricamente, aos ratos cafeĂ­na (30 mg·kg-1, uma vez ao dia), polifenol do chĂĄ(400 mg·kg-1, uma vez ao dia) ou daidzeĂ­na (13,5 mg·kg-1, uma vez ao dia), por 14 dias, seguindo-se a administração de lansoprazol (8 mg·kg-1) no 15Âș. dia. As concentraçÔes plasmĂĄticas do lansoprazol e de seus dois metabĂłlitos primĂĄrios, 5-hidroxilansoprazol e sulfona de lansoprazol, foram determinadas por cromatografia lĂ­quida de alta eficiĂȘncia acoplada com espectrometria de massas (CLAE-EM/EM). O polifenol do chĂĄ elevou, significativamente, a Área Sob a Curva (ASC) do lansoprazol de 680,29 ± 285,99 para 949,76 ± 155,18 ÎŒg/L.h e reduziu a da sulfona de lansoprazol de 268,82 ± 82,37 para 177,72 ± 29,73 ÎŒg/L.h. A daidzeĂ­na aumentou a ASC do lansoprazol de 680,29 ± 285,99 para 1130,44 ± 97,6 ÎŒg/L.h e reduziu a da sulfona de lansoprazol de 268,82 ± 82,37 para 177,72 ± 29,73 ÎŒg/L.h. A farmacocinĂ©tica do 5-hidroxilansoprazol permaneceu intacta na presença de polifenol do chĂĄ ou daidzeĂ­na. A cafeĂ­na nĂŁo afetou a farmacocinĂ©tica do lansoprazol e de seus metabĂłlitos. Os resultados sugerem que o polifenol do chĂĄ e a daidzeĂ­na podem inibir o metabolismo in vivo do lansoprazol por supressĂŁo da CYP3A.The aim of this study was to evaluate the effects of caffeine, tea polyphenol and daidzein on the pharmacokinetics of lansoprazole and its metabolites. Rats were intragastrically administered caffeine (30 mg·kg-1, once per day), tea polyphenol (400 mg·kg-1, once per day) or daidzein (13.5 mg·kg-1, once per day) for 14 days, followed by an intragastric administration of lansoprazole (8 mg·kg-1) on the 15th day. The plasma concentrations of lansoprazole and its two primary metabolites, 5-hydroxylansoprazole and lansoprazole sulfone, were determined by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Tea polyphenol significantly elevated the Area Under the Curve (AUC) of lansoprazole from 680.29 ± 285.99 to 949.76 ± 155.18 ÎŒg/L.h and reduced that of lansoprazole sulfone from 268.82 ± 82.37 to 177.72 ± 29.73 ÎŒg/L.h. Daidzein increased the AUC of lansoprazole from 680.29 ± 285.99 to 1130.44 ± 97.6 ÎŒg/L.h and decreased that of lansoprazole sulfone from 268.82 ± 82.37 to 116.23 ± 40.14 ÎŒg/L.h. The pharmacokinetics of 5-hydroxylansoprazole remained intact in the presence of tea polyphenol or daidzein. Caffeine did not affect the pharmacokinetics of lansoprazole and its metabolites. The results imply that tea polyphenol and daidzein may inhibit the in vivo metabolism of lansoprazole by suppressing CYP3A

    STUB1 suppresseses tumorigenesis and chemoresistance through antagonizing YAP1 signaling

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    Yes-associated protein (YAP) is a component of the canonical Hippo signaling pathway that is known to play essential roles in modulating organ size, development, and tumorigenesis. Activation or upregulation of YAP1, which contributes to cancer cell survival and chemoresistance, has been verified in different types of human cancers. However, the molecular mechanism of YAP1 upregulation in cancer is still unclear. Here we report that the E3 ubiquitin ligase STUB1 ubiquitinates and destabilizes YAP1, thereby inhibiting cancer cell survival. Low levels of STUB1 expression were correlated with increased protein levels of YAP1 in human gastric cancer cell lines and patient samples. Moreover, we revealed that STUB1 ubiquitinates YAP1 at the K280 site by K48-linked polyubiquitination, which in turn increases YAP1 turnover and promotes cellular chemosensitivity. Overall, our study establishes YAP1 ubiquitination and degradation mediated by the E3 ligase STUB1 as an important regulatory mechanism in gastric cancer, and provides a rationale for potential therapeutic interventions

    Identification and Nearly Full-Length Genome Characterization of Novel Porcine Bocaviruses

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    The genus bocavirus includes bovine parvovirus (BPV), minute virus of canines (MVC), and a group of human bocaviruses (HBoV1-4). Using sequence-independent single primer amplification (SISPA), a novel bocavirus group was discovered with high prevalence (12.59%) in piglet stool samples. Two nearly full-length genome sequences were obtained, which were approximately 5,100 nucleotides in length. Multiple alignments revealed that they share 28.7–56.8% DNA sequence identity with other members of Parvovirinae. Phylogenetic analyses indicated their closest neighbors were members of the genus bocavirus. The new viruses had a putative non-structural NP1 protein, which was unique to bocaviruses. They were provisionally named porcine bocavirus 1 and 2 (PBoV1, PBoV2). PBoV1 and PBoV2 shared 94.2% nucleotide identity in NS1 gene sequence, suggesting that they represented two different bocavirus species. Two additional samples (6V, 7V) were amplified for 2,407 bp and 2,434 bp products, respectively, including a partial NP1 gene and the complete VP1 gene; Phylogenetic analysis indicated that 6Vand 7V grouped with PBoV1 and PBoV2 in the genus of bocavirus, but were in the separate clusters. Like other parvoviruses, PBoV1, PBoV2, 6Vand 7V also contained a putative secretory phospholipase A2 (sPLA2) motif in the VP1 unique region, with a conserved HDXXY motif in the catalytic center. The conserved motif YXGXF of the Ca2+-binding loop of sPLA2 identified in human bocavirus was also found in porcine bocavirus, which differs from the YXGXG motif carried by most other parvoviruses. The observation of PBoV and potentially other new bocavirus genus members may aid in molecular and functional characterization of the genus bocavirus
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