144 research outputs found

    Informal traders lock horns with the formal milk industry: the role of research in pro-poor dairy policy shift in Kenya

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    A polarizable atomic multipole-based force field for the membrane bilayer models 1,2-dioleoyl-phosphocholine (DOPC) and 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) has been developed. The force field adopts the same framework as the Atomic Multipole Optimized Energetics for Biomolecular Applications (AMOEBA) model, in which the charge distribution of each atom is represented by the permanent atomic monopole, dipole and quadrupole moments. Many-body polarization including the inter- and intra-molecular polarization is modelled in a consistent manner with distributed atomic polarizabilities. The van der Waals parameters were first transferred from existing AMOEBA parameters for small organic molecules and then optimised by fitting to ab initio intermolecular interaction energies between models and a water molecule. Molecular dynamics simulations of the two aqueous DOPC and POPE membrane bilayer systems, consisting of 72 model molecules, were then carried out to validate the force field parameters. Membrane width, area per lipid, volume per lipid, deuterium order parameters, electron density profile, etc. were consistent with experimental values

    Study of Solutions to a Fourth Order Parabolic Equation∗

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    This paper studies a fourth-order parabolic equation ut + ε(unuxxx)x − δ|uxx|muxx = 0 with the boundary conditions uxx = 0, u = l and the initial condition u(x, 0) = u0(x). The existence of solutions is obtained from the semidiscretization method. When the initial function is close to a constant steady state solution, the uniqueness of the bounded solutions is obtained. Finally, by the iteration technique from its semi-discrete problem, the solution exponentially converges to a constant steady state solution as the time tends to infinity

    IVIG Delays Onset in a Mouse Model of Gerstmann-Sträussler-Scheinker Disease

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    Our previous studies showed that intravenous immunoglobulin (IVIG) contained anti-Aβ autoantibodies that might be able to treat Alzheimer's disease (AD). Recently, we identified and characterized naturally occurring autoantibodies against PrP from IVIG. Although autoantibodies in IVIG blocked PrP fibril formation and PrP neurotoxicity in vitro, it remained unknown whether IVIG could reduce amyloid plaque pathology in vivo and be used to effectively treat animals with prion diseases. In this study, we used Gerstmann-Sträussler-Scheinker (GSS)-Tg (PrP-A116V) transgenic mice to test IVIG efficacy since amyloid plaque formation played an important role in GSS pathogenesis. Here, we provided strong evidence that demonstrates how IVIG could significantly delay disease onset, elongate survival, and improve clinical phenotype in Tg (PrP-A116V) mice. Additionally, in treated animals, IVIG could markedly inhibit PrP amyloid plaque formation and attenuate neuronal apoptosis at the age of 120 days in mice. Our results indicate that IVIG may be a potential, effective therapeutic treatment for GSS and other prion diseases

    GDNF secreted from adipose-derived stem cells stimulates VEGF-independent angiogenesis

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    Adipose tissue stroma contains a population of mesenchymal stem cells (MSC) promote new blood vessel formation and stabilization. These adipose-derived stem cells (ASC) promote de novo formation of vascular structures in vitro. We investigated the angiogenic factors secreted by ASC and discovered that glial-derived neurotrophic factor (GDNF) is a key mediator for endothelial cell network formation. It was found that both GDNF alone or present in ASC-conditioned medium (ASC-CM) stimulated capillary network formation by using human umbilical vein endothelial cells (HUVECs) and such an effect was totally independent of vascular endothelial growth factor (VEGF) activity. Additionally, we showed stimulation of capillary network formation by GDNF, but not VEGF, could be blocked by the Ret (rearranged during transfection) receptor antagonist RPI-1, a GDNF signaling inhibitor. Furthermore, GDNF were found to be overexpressed in cancer cells that were resistant to the anti-angiogenic treatment using the VEGF antibody. Cancer cells in the liver hepatocellular carcinoma (HCC), a non-nervous related cancer, highly overexpressed GDNF as compared to normal liver cells. Our data strongly suggest that, in addition to VEGF, GDNF secreted by ASC and HCC cells, may be another important factor promoting pathological neovascularization. Thus, GDNF may be a potential therapeutic target for HCC and obesity treatments

    A Modified Nonlinear Damage Accumulation Model for Fatigue Life Prediction Considering Load Interaction Effects

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    Many structures are subjected to variable amplitude loading in engineering practice. The foundation of fatigue life prediction under variable amplitude loading is how to deal with the fatigue damage accumulation. A nonlinear fatigue damage accumulation model to consider the effects of load sequences was proposed in earlier literature, but the model cannot consider the load interaction effects, and sometimes it makes a major error. A modified nonlinear damage accumulation model is proposed in this paper to account for the load interaction effects. Experimental data of two metallic materials are used to validate the proposed model. The agreement between the model prediction and experimental data is observed, and the predictions by proposed model are more possibly in accordance with experimental data than that by primary model and Miner’s rule. Comparison between the predicted cumulative damage by the proposed model and an existing model shows that the proposed model predictions can meet the accuracy requirement of the engineering project and it can be used to predict the fatigue life of welded aluminum alloy joint of Electric Multiple Units (EMU); meanwhile, the accuracy of approximation can be obtained from the proposed model though more simple computing process and less material parameters calling for extensive testing than the existing model

    A modified Ranson score to predict disease severity, organ failure, pancreatic necrosis, and pancreatic infection in patients with acute pancreatitis

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    BackgroundAlthough there are several scoring systems currently used to predict the severity of acute pancreatitis, each of them has limitations. Determine the accuracy of a modified Ranson score in predicting disease severity and prognosis in patients with acute pancreatitis (AP).MethodsAP patients admitted or transferred to our institution were allocated to a modeling group (n = 304) or a validation group (n = 192). A modified Ranson score was determined by excluding the fluid sequestration parameter and including the modified computed tomography severity index (CTSI). The diagnostic performance of the modified Ranson score was compared with the Ranson score, modified CTSI, and bedside index of severity in acute pancreatitis (BISAP) score in predicting disease severity, organ failure, pancreatic necrosis and pancreatic infection.ResultsThe modified Ranson score had significantly better accuracy that the Ranson score in predicting all four outcome measures in the modeling group and in the validation group (all p < 0.05). For the modeling group the modified Ranson score had the best accuracy for predicting disease severity and organ failure, and second-best accuracy for predicting pancreatic necrosis and pancreatic infection. For the verification group, it had the best accuracy for predicting organ failure, second-best accuracy for predicting disease severity and pancreatic necrosis, and third-best accuracy for predicting pancreatic infection.ConclusionThe modified Ranson score provided better accuracy than the Ranson score in predicting disease severity, organ failure, pancreatic necrosis and pancreatic infection. Relative to the other scoring systems, the modified Ranson system was superior in predicting organ failure

    Identification of a venetoclax-resistance prognostic signature base on 6-senescence genes and its clinical significance for acute myeloid leukemia

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    BackgroundSatisfactory responses can be obtained for acute myeloid leukemia (AML) treated by Venetoclax (VEN)-based therapy. However, there are still quite a few AML patients (AMLs) resistant to VEN, and it is critical to understand whether VEN-resistance is regulated by senescence.MethodsHere, we established and validated a signature for predicting AML prognosis based on VEN resistance-related senescence genes (VRSGs). In this study, 51 senescence genes were identified with VEN-resistance in AML. Using LASSO algorithms and multiple AML cohorts, a VEN-resistance senescence prognostic model (VRSP-M) was developed and validated based on 6-senescence genes.ResultsAccording to the median score of the signature, AMLs were classified into two subtypes. A worse prognosis and more adverse features occurred in the high-risk subtype, including older patients, non-de novo AML, poor cytogenetics, adverse risk of European LeukemiaNet (ELN) 2017 recommendation, and TP53 mutation. Patients in the high-risk subtype were mainly involved in monocyte differentiation, senescence, NADPH oxidases, and PD1 signaling pathway. The model’s risk score was significantly associated with VEN-resistance, immune features, and immunotherapy response in AML. In vitro, the IC50 values of ABT-199 (VEN) rose progressively with increasing expression of G6PD and BAG3 in AML cell lines.ConclusionsThe 6-senescence genes prognostic model has significant meaning for the prediction of VEN-resistance, guiding personalized molecularly targeted therapies, and improving AML prognosis

    Association between serum nickel and oral cancer incidence using propensity score matching and inverse probability of treatment weighting

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    BackgroundThe association between serum nickel (Ni) and oral cancer incidence is unclear and most of the previous studies were observational studies that did not control for confounding factors between groups.ObjectiveTo assess the correlation of serum Ni with oral cancer incidence based on propensity score matching (PSM) and inverse probability of treatment weighting (IPTW).MethodsA cohort of 456 newly diagnosed oral cancer patients was recruited from the First Hospital of Fujian Medical University during November 2011 to May 2019, and residents ordered their health check-up in hospitals or local community health centers over the same period were selected as a control group, which included a total of 1410 participants. Serum Ni was evaluated by inductively coupled plasma mass spectrometry. Case-control pairs were selected using a 1:1 PSM (caliper value of 0.02), and the study subjects in the case group and control group were weighted for subsequent analysis by IPTW. The general characteristics of the study subjects were tested for equilibrium before and after matching by chi-square test and standardized mean difference (SMD). This was followed by exploring the potential nonlinear dose-response relationship between serum Ni and oral cancer using restricted cubic splines as well as analyzing the association between serum Ni and oral cancer incidence by conditional logistic regression and weighted logistic regression.ResultsAfter controlling for between-group covariates by PSM and IPTW, the dose-response curves demonstrated that the risk of developing oral cancer tended to decline and then increase with the increasing serum Ni level. The outcome of the analysis using PSM demonstrated that as compared to the control group, the risk of developing oral cancer in the 0.09-16.80 μg·L−1 serum Ni group was negatively correlated with serum Ni level (OR=0.36, 95%CI: 0.24-0.54), whereas the risk of developing oral cancer in the >16.80 μg·L−1 serum Ni group was positively correlated with serum Ni level (OR=5.43, 95%CI: 2.76-10.68). After applying IPTW, a negative association was found between the risk of oral cancer and serum Ni concentration within a serum Ni window ranging from 0.09 to 20.55 μg·L−1 (OR=0.39, 95%CI: 0.29-0.52), while a positive association with an OR and 95%CI of 5.54 (3.62-8.49) for the Ni concentration > 20.55 μg·L−1.ConclusionIn this study, a J-shaped relationship between serum Ni concentration and the risk of developing oral cancer is found, which shows that high serum Ni concentration (>20.55 μg·L−1) may be a risk factor for oral cancer

    Self-healing metallo-supramolecular polymers from a ligand macromolecule synthesized via copper-catalyzed azide-alkyne cycloaddition and thiol-ene double "click" reactions

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    Natural Science Foundation of China [21074103]; Fundamental Research Funds for the Central Universities [2010121018]; Scientific Research Foundation for Returned Scholars; NFFTBS [J1210014]In this study, we develop a series of new materials that can simultaneously and reversibly self-heal without external stimuli based on metallo-supramolecular interactions. Multiple tridentate 2,6-bis(1,2,3-trizaol-4-yl)-pyridine (BTP) ligand units synthesized via a copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" reaction are incorporated into the polymer backbone of a ligand macromolecule through a thiol-ene "click" reaction. 3D transient supramolecular networks are formed from the ligand macromolecule upon coordination with transition and/or lanthanide metal ions. As compared to the ligand macromolecule, the resultant supramolecular films exhibit improved mechanical properties, such as Young's modulus, strength and toughness, which can be readily tuned by the stoichiometric ratio of Zn2+ to Eu3+ to Tb3+. The supramolecular films exhibit characteristics of weakly crosslinked networks where the storage modulus G' and loss modulus G '' scaled with normalized frequency omega a(T) by the same slope of 0.5. Both the supramolecular bulk films and gels are found to exhibit fast and effective self-healing properties by virtue of the kinetically labile nature of the metal-ligand interactions

    Ultrathin Si/CNTs Paper-Like Composite for Flexible Li-Ion Battery Anode With High Volumetric Capacity

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    Thin and lightweight flexible lithium-ion batteries (LIBs) with high volumetric capacities are crucial for the development of flexible electronic devices. In the present work, we reported a paper-like ultrathin and flexible Si/carbon nanotube (CNT) composite anode for LIBs, which was realized by conformal electrodeposition of a thin layer of silicon on CNTs at ambient temperature. This method was quite simple and easy to scale up with low cost as compared to other deposition techniques, such as sputtering or CVD. The flexible Si/CNT composite exhibited high volumetric capacities in terms of the total volume of active material and current collector, surpassing the most previously reported Si-based flexible electrodes at various rates. In addition, the poor initial coulombic efficiency of the Si/CNT composites can be effectively improved by prelithiation treatment and a commercial red LED can be easily lighted by a full pouch cell using a Si/CNT composite as a flexible anode under flat or bent states. Therefore, the ultrathin and flexible Si/CNT composite is highly attractive as an anode material for flexible LIBs
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