3,680 research outputs found
A regional information-based multi-attribute and multi-objective decision-making approach for sustainable supplier selection and order allocation
Although extant studies proposed various models and frameworks for sustainable supplier selection problems, they paid limited attention to the incorporation of regional economic, social, and environmental factors simultaneously for global supply chain design due to the difficulty in reflecting varies dimensions of the global business environment and their associated risk in a decision model. Existing supplier selection models also tend to focus on the formulation of a simplified supply chain structure rather than considering more realistic supply chain operations under multiple sourcing and product designs. To facilitate the complex decision-making process of global supplier selection problems, this study proposes an integrated approach that consists of two phases to effectively reflect the multi-perspectives of global supply chain design for sustainability. The first phase identifies sustainable supplier regions through multi-attribute utility theory, considering four regional sustainability indices for economic and social factors in global business and logistics, to reflect the decision maker\u27s risk attitudes on global business opportunities. In the second phase, a multi-objective integer linear programming model for multiple sourcing and multiple product designs that minimizes economic and environmental objectives is applied to find optimal suppliers in the regions selected from the first phase and their order quantities. The proposed approach is illustrated through a bicycle supplier selection case study. The results show that the multi-objective sustainable decision under a multiple sourcing strategy for different product designs leads to a supply chain that is significantly different from the single-objective non-sustainable decisions. The case study under different decision scenarios shows that a decision maker should hold a balanced perspective under the multi-objective decision environment for sustainable supply chain design
Palatini Formalism of 5-Dimensional Kaluza-Klein Theory
The Einstein field equations can be derived in dimensions () by the
variations of the Palatini action. The Killing reduction of 5-dimensional
Palatini action is studied on the assumption that pentads and Lorentz
connections are preserved by the Killing vector field. A Palatini formalism of
4-dimensional action for gravity coupled to a vector field and a scalar field
is obtained, which gives exactly the same fields equations in Kaluza-Klein
theory.Comment: 10 page
Life cycle assessment comparison of wooden and plastic pallets in the grocery industry
Wooden and plastic pallets are used extensively in global trade to transport finished goods and products. This article compares the life cycle performance of treated wooden and plastic pallets through a detailed cradleâtoâgrave life cycle assessment (LCA), and conducts an analysis of the various phytosanitary treatments. The LCA investigates and evaluates the environmental impacts due to the resources consumed and emissions of the product throughout its life cycle. The environmental impacts of the pallets are compared on a oneâtrip basis and a 100,000âtrips basis. Impact categories are chosen with respect to environmental concerns. The results show that on a oneâtrip basis, wooden pallets with conventional and radio frequency (RF) heat treatment incur an overall carbon footprint of 71.8% and 80.3% lower, respectively, than plastic pallets during their life cycle; and in comparison with wooden pallets treated with methyl bromide fumigation, they incur 20% and 30% less overall carbon footprint. Theoretical calculations of the resource consumption and emissions of RF treatment of pallets suggest that dielectric technology may provide a lowerâcarbon alternative to both current ISPM 15âapproved treatments and to plastic pallets. Methyl bromide fumigation (15.95 kg CO2 equivalent [eq.]) has a larger carbon footprint than conventional heat treatment (12.69 kg CO2 eq.) of pallets. For the 100,000âtrips basis, the differences are even more significant. The results recommend that wooden pallets are more environmentally friendly than plastic pallets, and conventional and RF heat treatment for wooden pallets is more sustainable than methyl bromide fumigation treatment
Nucleosomes in colorectal cancer patients during radiochemotherapy
Apoptotic markers and tumor-associated antigens might be suitable to indicate the response to radiochemotherapy early. We analyzed the courses of nucleosomes, CEA, CA 19-9 and CYFRA 21-1 in 25 colorectal cancer patients during radiochemotherapy (4 postoperative, 13 preoperative, 8 local relapse therapy). Blood was taken before therapy, daily during the first week, once weekly during the following weeks, and at the end of the radiochemotherapy. After a temporary decline 6 h after the first irradiation, nucleosomes rose in most patients rapidly reaching a maximum during the first days which was followed by a subsequent decrease. In patients receiving postoperative therapy after complete resection of tumor, nucleosome levels generally were lower than in patients with preoperative or relapse therapy. Correspondingly, CEA, CA 19-9 and CYFRA 21-1 levels of postoperatively treated patients were the lowest whereas those with tumor relapse had the highest ones. During preoperative therapy, lower nucleosome concentrations were found in patients with response to therapy resulting in a smaller area under the curve of days 1-3 (AUC) than in those with progressive disease (p = 0.028). The other parameters did not indicate the response to therapy at the initial treatment phase. In conclusion, the course of nucleosomes (AUC) might be valuable for the early prediction of therapy response in preoperatively treated colorectal cancer patients. Copyright (c) 2006 S. Karger AG, Basel
The pseudokinase MLKL mediates programmed hepatocellular necrosis independently of RIPK3 during hepatitis
Although necrosis and necroinflammation are central features of many liver diseases, the role of programmed necrosis in the context of inflammation-dependent hepatocellular death remains to be fully determined. Here, we have demonstrated that the pseudokinase mixed lineage kinase domain-like protein (MLKL), which plays a key role in the execution of receptor interacting protein (RIP) lcinase-dependent necroptosis, is upregulated and activated in human autoimmune hepatitis and in a murine model of inflammation-dependent hepatitis. Using genetic and pharmacologic approaches, we determined that hepatocellular necrosis in experimental hepatitis is driven by an MLKL-dependent pathway that occurs independently of RIPK3. Moreover, we have provided evidence that the cytotoxic activity of the proinflammatory cytokine IFN-gamma in hepatic inflammation is strongly connected to induction of MLKL expression via activation of the transcription factor STAT1. In summary, our results reveal a pathway for MLKL-dependent programmed necrosis that is executed in the absence of RIPK3 and potentially drives the pathogenesis of severe liver diseases
Synthesis, antitubercular activity and mechanism of resistance of highly effective thiacetazone analogues
Defining the pharmacological target(s) of currently used drugs and developing new analogues with greater potency are both important aspects of the search for agents that are effective against drug-sensitive and drug-resistant Mycobacterium tuberculosis. Thiacetazone (TAC) is an anti-tubercular drug that was formerly used in conjunction with isoniazid, but removed from the antitubercular chemotherapeutic arsenal due to toxic side effects. However, several recent studies have linked the mechanisms of action of TAC to mycolic acid metabolism and TAC-derived analogues have shown increased potency against M. tuberculosis. To obtain new insights into the molecular mechanisms of TAC resistance, we isolated and analyzed 10 mutants of M. tuberculosis that were highly resistant to TAC. One strain was found to be mutated in the methyltransferase MmaA4 at Gly101, consistent with its lack of oxygenated mycolic acids. All remaining strains harbored missense mutations in either HadA (at Cys61) or HadC (at Val85, Lys157 or Thr123), which are components of the bhydroxyacyl-ACP dehydratase complex that participates in the mycolic acid elongation step. Separately, a library of 31 new TAC analogues was synthesized and evaluated against M. tuberculosis. Two of these compounds, 15 and 16, exhibited minimal inhibitory concentrations 10-fold lower than the parental molecule, and inhibited mycolic acid biosynthesis in a dose-dependent manner. Moreover, overexpression of HadAB HadBC or HadABC in M. tuberculosis led to high level resistance to these compounds, demonstrating that their mode of action is similar to that of TAC. In summary, this study uncovered new mutations associated with TAC resistance and also demonstrated that simple structural optimization of the TAC scaffold was possible and may lead to a new generation of TAC-derived drug candidates for the potential treatment of tuberculosis as mycolic acid inhibitors
Bulk viscous cosmological model with interacting dark fluids
The objective of the present work is to study a cosmological model for a
spatially flat Universe whose constituents are a dark energy field and a matter
field which includes baryons and dark matter. The constituents are supposed to
be in interaction and irreversible processes are taken into account through the
inclusion of a non-equilibrium pressure. The non-equilibrium pressure is
considered to be proportional to the Hubble parameter within the framework of a
first order thermodynamic theory. The dark energy and matter fields are coupled
by their barotropic indexes, which are considered as functions of the ratio
between their energy densities. The free parameters of the model are adjusted
from the best fits of the Hubble parameter data. A comparison of the viscous
model with the non-viscous one is performed. It is shown that the equality of
the dark energy and matter density parameters and the decelerated-accelerated
transition occur at earlier times when the irreversible processes are present.
Furthermore, the density and deceleration parameters and the distance modulus
have the correct behavior which is expected for a viable scenario of the
present status of the Universe.Comment: 10 pages, 7 figures, to be published in Brazilian Journal of Physic
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