GLOBAL EXISTENCE OF SOLUTIONS TO AN ATTRACTION-REPULSION CHEMOTAXIS MODEL WITH GROWTH

An attraction-repulsion chemotaxis model with nonlinear chemotactic sensitivity functions and growth source is considered. The global-in-time existence and boundedness of solutions are proved under some conditions on the nonlinear sensitivity functions and growth source function. Our results improve the earlier ones for the linear sensitivity functions

Global existence of solutions and uniform persistence of a diffusive predator-prey model with prey-taxis

This paper proves the global existence and boundedness of solutions to a general reaction diffusion predator prey system with prey-taxis defined on a smooth bounded domain with no-flux boundary condition. The result holds for domains in arbitrary spatial dimension and small prey-taxis sensitivity coefficient. This paper also proves the existence of a global attractor and the uniform persistence of the system under some additional conditions. Applications to models from ecology and chemotaxis are discussed. (C) 2016 Elsevier Inc. All rights reserved

Multi-Attribute Utility Preference Robust Optimization: A Continuous Piecewise Linear Approximation Approach

In this paper, we consider a multi-attribute decision making problem where the decision maker's (DM's) objective is to maximize the expected utility of outcomes but the true utility function which captures the DM's risk preference is ambiguous. We propose a maximin multi-attribute utility preference robust optimization (UPRO) model where the optimal decision is based on the worst-case utility function in an ambiguity set of plausible utility functions constructed using partially available information such as the DM's specific preferences between some lotteries. Specifically, we consider a UPRO model with two attributes, where the DM's risk attitude is multivariate risk-averse and the ambiguity set is defined by a linear system of inequalities represented by the Lebesgue-Stieltjes (LS) integrals of the DM's utility functions. To solve the maximin problem, we propose an explicit piecewise linear approximation (EPLA) scheme to approximate the DM's true unknown utility so that the inner minimization problem reduces to a linear program, and we solve the approximate maximin problem by a derivative-free (Dfree) method. Moreover, by introducing binary variables to locate the position of the reward function in a family of simplices, we propose an implicit piecewise linear approximation (IPLA) representation of the approximate UPRO and solve it using the Dfree method. Such IPLA technique prompts us to reformulate the approximate UPRO as a single mixed-integer program (MIP) and extend the tractability of the approximate UPRO to the multi-attribute case. Furthermore, we extend the model to the expected utility maximization problem with expected utility constraints where the worst-case utility functions in the objective and constraints are considered simultaneously. Finally, we report the numerical results about performances of the proposed models.Comment: 50 pages,18 figure

Effect of Gelsemium elegans

Gelsemium elegans (GE) is a kind of well-known toxic plant. It can be detoxified by Mussaenda pubescens (MP), but the detoxification mechanism is still unclear. Thus, a detoxification herbal formula (GM) comprising GE and MP was derived. The Caco-2 cells monolayer model was used to evaluate GM effects on transporting six kinds of indole alkaloids of GE. The bidirectional transport studies demonstrated that absorbance percentage of indole alkaloids in GE increased linearly over time. But in GM, Papp (AP→BL) values of the most toxic members, gelsenicine, humantenidine, and gelsevirine, were lower than that of Papp (BL→AP) (P<0.05). The prominent analgesic effect members, gelsemine and koumine, were approximately 1.00 in γ values. Nowhere was this increasing efflux more pronounced than in the case of indole alkaloids with N-O structure. In the presence of verapamil, the γ values of humantenidine, gelsenicine, gelsevirine, and humantenine were decreased by 43.69, 41.42, 36.00, and 8.90 percent, respectively. The γ values in presence of ciclosporin were homologous with a decrease of 42.32, 40.59, 34.00, and 15.07 percent. It suggested that the efflux transport was affected by transporters. Taken together, due to the efflux transporters participation, the increasing efflux of indole alkaloids from GM was found in Caco-2 cells

Formation of Highly Oxidized Radicals and Multifunctional Products from the Atmospheric Oxidation of Alkylbenzenes

Aromatic hydrocarbons contribute significantly to tropospheric ozone and secondary organic aerosols (SOA). Despite large efforts in elucidating the formation mechanism of aromatic-derived SOA, current models still substantially underestimate the SOA yields when comparing to field measurements. Here we present a new, up to now undiscovered pathway for the formation of highly oxidized products from the OH-initiated oxidation of alkyl benzenes based on theoretical and experimental investigations. We propose that unimolecular H-migration followed by O-2-addition, a so-called autoxidation step, can take place in bicyclic peroxy radicals (BPRs), which are important intermediates of the OH -initiated oxidation of aromatic compounds. These autoxidation steps lead to the formation of highly oxidized multifunctional compounds (HOMs), which are able to form SOA. Our theoretical calculations suggest that the intramolecular H-migration in BPRs of substituted benzenes could be fast enough to compete with bimolecular reactions with HO2 radicals or NO under atmospheric conditions. The theoretical findings are experimentally supported by flow tube studies using chemical ionization mass spectrometry to detect the highly oxidized peroxy radical intermediates and closed-shell products. This new unimolecular BPR route to form HOMs in the gas phase enhances our understanding of the aromatic oxidation mechanism, and contributes significantly to a better understanding of aromatic-derived SOA in urban areas.Peer reviewe

High sensitivity temperature sensor based on a helically twisted photonic crystal fiber

Helically twisted photonic crystal fibers (HT-PCFs) provide additional opportunities for controlling the light propagation characteristics and improving the sensing performances. In this paper, a toluene and gold wire-filled HT-PCF was proposed and designed for high sensitivity temperature sensing. The influences of the structure parameters on the confinement loss, sensitivity, and resolution of the proposed HT-PCF were investigated. For the optimized HT-PCF, the average sensitivity is as high as 14.35 and 17.29 nm/℃ in the temperature range of −20 to 20 ℃ and 20 to 70 ℃, respectively. Moreover, the proposed HT-PCF-based temperature sensor is insensitive to the hydrostatic pressure. Finally, the detailed fabrication process of the toluene and gold wire-filled HT-PCF temperature sensor is proposed. It is believed that the proposed HT-PCF temperature sensor has potential applications in the fields of the environmental monitoring, medical diagnostics, etc

Quercetin Pretreatment Attenuates Hepatic Ischemia Reperfusion-Induced Apoptosis and Autophagy by Inhibiting ERK/NF- κ

Background. Hepatic ischemia reperfusion (IR) injury is a common phenomenon in transplantation or trauma. The aim of the present study was to determine the protective effect of quercetin (QE) on hepatic IR injury via the ERK/NF-κB pathway. Methods. Mice were randomized into the sham, IR, QE100 + IR, and QE200 + IR groups. Quercetin was administered intragastrically daily at two doses (100 mg/kg and 200 mg/kg) for 5 days prior to IR injury. The expression levels of liver enzymes, inflammatory cytokines, and other marker proteins were determined at 2, 8, and 24 hours after IR. And they were compared among these groups. Results. Compared with the IR group, the treatment of QE reduced the release of cytokines, leading to inhibition of apoptosis and autophagy via downregulation of the ERK/NF-κB pathway in this model of hepatic IR injury. Conclusion. Apoptosis and autophagy caused by hepatic IR injury were inhibited by QE following a reduction in the release of inflammatory cytokines, and the relationship between the two may be associated with inactivation of the ERK/NF-κB pathway

Clinical Study Metformin and Diammonium Glycyrrhizinate Enteric-Coated Capsule versus Metformin Alone versus Diammonium Glycyrrhizinate Enteric-Coated Capsule Alone in Patients with Nonalcoholic Fatty Liver Disease and Type 2 Diabetes Mellitus

Objective. The present study was conducted to compare the efficacy of metformin combined with diammonium glycyrrhizinate enteric-coated capsule (DGEC) versus metformin alone versus DGEC alone for the treatment of nonalcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM). Subjects and Methods. 163 patients with NAFLD and T2DM were enrolled in this 24-week study and were randomized to one of three groups: group 1 was treated with metformin alone; group 2 was treated with DGEC alone; group 3 received metformin plus DGEC combination therapy. Anthropometric parameters, liver function, lipid profile, serum ferritin (SF), metabolic parameters, liver/spleen computed tomography (CT) ratio, and fibroscan value were evaluated at baseline and after 8, 16, and 24 weeks of treatment. Results. After 24 weeks, significant improvements in all measured parameters were observed in three groups ( &lt; 0.05) except for the improvements in low density lipoprotein cholesterol (LDL-C) and metabolic parameters in group 2 which did not reach statistical significance ( &gt; 0.05). Compared with group 1 and group 2, the patients in group 3 had greater reductions in observed parameters apart from CB and TB ( &lt; 0.05). Conclusions. This study showed that metformin plus DGEC was more effective than metformin alone or DGEC alone in reducing liver enzymes, lipid levels, and metabolic parameters and ameliorating the degree of hepatic fibrosis in patients with NAFLD and T2DM

Community environmental satisfaction: its forms and impact on migrants' happiness in urban China

BACKGROUND: The great number of internal migrants has become an important part of China's urban population. Improving migrants' well-being is emerging as a key to the state policy emphasized in China's New-type Urbanization Plan. Previous studies on subjective well-being (SWB) have primarily focused on the impacts of objective measures of community environment and consider migrants as a homogeneous group. This study extends the literature by exploring the impacts of perceived community environment on migrants' SWB and incorporating cohort differences in the analysis. METHODS: We use the 2015 national scale data-China Household Financial Survey (CHFS) data-to analyse the different forms of community environmental satisfaction and their impacts on migrants' subjective well-being. A total of 12,607 migrants were sampled from 29 of mainland China's 31 provinces. Latent class analysis is applied to explore the potential forms of community environmental satisfaction; multinomial and ordinal logistic regression models are constructed to examine the sociodemographic characteristics of different forms of community environmental satisfaction and the association between community environmental satisfaction and subjective well-being among migrant cohorts in urban China. RESULTS: Latent class analysis defines four distinctive latent classes, which mirror four different domains of migrants' perception of their local environments. They are called 'unsatisfying local environment', 'satisfying social environment', 'satisfying physical environment', and 'satisfying social life'. Results from the multinomial logistic regression model reveals that the four forms of community environmental satisfaction are underpinned by distinct sociodemographic characteristics. Results from a series of ordinal logistic regression models show that different forms of community environmental satisfaction, in particular satisfaction with the physical environment and with social life, are positively associated with migrants' happiness. The model results also suggest that cohort differences do exist among migrants. The positive effect of a satisfying physical environment on happiness tends to be greater in younger cohorts, while the positive effect of a satisfying social life on SWB is more observable in older cohorts. CONCLUSION: Satisfaction with community environment has a salient impact on urban Chinese migrants' happiness. For their SWB, improving migrants' physical living environments and social lives is relatively more important than social environment, which in a way mirrors migrants' current status with its deficiencies in terms of a comfortable living environment and social life. Moreover, there exist cohort differences that should be considered when making policies to enhance migrants' subjective well-being