DNA detection by dye labeled oligonucleotides using surface enhanced Raman spectroscopy

1. Download : Download high-res image (290KB)
2. Download : Download full-size image

     

Optimal harvesting policy of an inland fishery resource under incomplete information

A new mathematical model for finding the optimal harvesting policy of an inland fishery resource under incomplete information is proposed in this paper. The model is based on a stochastic control formalism in a regime‐switching environment. The incompleteness of information is due to uncertainties involved in the body growth rate of the fishery resource: a key biological parameter. Finding the most cost‐effective harvesting policy of the fishery resource ultimately reduces to solving a terminal and boundary value problem of a Hamilton‐Jacobi‐Bellman equation: a nonlinear and degenerate parabolic partial differential equation. A simple finite difference scheme for solving the equation is then presented, which turns out to be convergent and generates numerical solutions that comply with certain theoretical upper and lower bounds. The model is finally applied to the management of Plecoglossus altivelis, a major inland fishery resource in Japan. The regime switching in this case is due to the temporal dynamics of benthic algae, the main food of the fish. Model parameter values are identified from field measurement results in 2017. Our computational results clearly show the dependence of the optimal harvesting policy on the river environmental and biological conditions. The proposed model would serve as a mathematical tool for fishery resource management under uncertainties.     

On Meeting Energy Balance Errors in Co-Simulations

The term co-simulation denotes the coupling of some simulation tools for dynamical systems into one big system by having them exchange data at points of a fixed time grid and extrapolating the received data into the interval, while none of the steps is repeated for iteration. From the global perspective, the simulation thus has a strong explicit component. Frequently, among the data passed across subsystem boundaries there are flows of conserved quantities, and as there is no iteration of steps, system-wide balances may not be fulfilled: the system is not solved as one monolithic equation system. If these balance errors accumulate, simulation results become inaccurate. Balance correction methods which compensate these errors by adding corrections for the balances to the signal in the next coupling time step have been considered in past research. But establishing the balance of one quantity a posteriori due to the time delay in general cannot establish the balances of quantities that depend on the exchanged quantities, usually energy. In most applications from physics, the balance of energy is equivalent to stability. In this paper, a method is presented which allows users to choose the quantity that should be balanced to be that energy, and to accurately balance it. This establishes also numerical stability for many classes of stable problems.     

地位差异视角下知识分享策略对组织学习的影响研究

组织学习是提高企业竞争能力的重要途径,人际学习是组织学习的重要组成部分。组织成员间普遍存在的地位差异,会直接影响个体的知识分享策略,继而影响组织学习。然而,以往的组织学习模型通常忽略了个体的地位差异,默认假设每个组织成员的地位是相同的。鉴于此,本文在组织学习经典仿真模型的基础上,引入地位这一特征,综合探讨正向差异化(高地位成员更愿意分享知识)、负向差异化(低地位成员更愿意分享知识)、以及同质化(不同地位的成员有相同的知识分享意愿)这三种知识分享策略对组织学习的影响机理。研究结果表明,三种知识分享策略下,知识分享水平和地位认可度对组织学习的作用关系和作用大小存在显著差异。但总体来说,仅当组织成员的地位认可度较高且知识分享水平较低时,同质化策略才最有利于组织学习;其他情境下,负向差异化策略更有利于提高组织学习绩效。     

Selective quantification of lacosamide in human plasma using UPLC–MS/MS: Application to pharmacokinetic study in healthy subjects with different doses

A practical, sensitive, and robust UPLC–MS/MS method was developed and validated to quantify lacosamide in human plasma. A simple one-step protein precipitation was used to extract lacosamide and labeled lacosamide-13C, D3 as an internal standard (IS) from 150-μL plasma. The extracts were analyzed on an Eclipse Plus C18 column (50 × 2.1 mm, 1.8 μm) using 0.1% formic acid in water and methanol:acetonitrile (50:50, v/v) under gradient conditions. The extracts were quantified on LCMS-8040 using electrospray ionization source operated in positive ionization and multiple reaction monitoring modes. The method showed good linearity from 0.02 to 20 μg/mL, which was adequate to cover lacosamide concentration assayed in formulations with different strengths. The bioanalytical assay was fully validated as per current regulatory guidelines. The intra-batch and inter-batch precision values of lacosamide were less than 4.6%. Lacosamide was found to be stable at different storage conditions. The extraction recoveries and IS-normalized matrix factors for lacosamide ranged from 97.17 to 99.68% and from 0.973 to 1.012, respectively. The validated method was successfully applied to a pharmacokinetic study with three lacosamide formulations (50, 100, and 200 mg) in 36 healthy subjects. The assay reliability was determined by reanalysis of 81 subject samples.     

Development and validation of LC–MS/MS method for quantification of bictegravir in human plasma and its application to an intracellular uptake study

A sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for quantification of bictegravir in human plasma. A small volume of only 50 μL aliquot of plasma was precipitated with acetonitrile containing an internal standard (IS). Chromatographic separation was performed on a Kinetex EVO C₁₈ column, 50 × 3.0 mm, 5 μm using an isocratic mobile phase containing 80:20 acetonitrile–water with 0.1% formic acid. A mass spectrometer was operated in ESI positive multiple reaction monitoring mode using the m/z 450.1/289.1 for bictegravir and 420.1/277.1 for IS. The dynamic range of the method was 1–10,000 ng/mL with a correlation coefficient of ≥0.9991. The precision results of calibration standards were in the range of 0.05–4.57% and accuracies were 95.07–104.70%. The mean extraction recovery was 98.64% with a precision of 2.91%. The method was validated as per US Food and Drug Administration guidelines and was found to be accurate and precise. The method was successfully applied to in vitro cellular uptake study.     

新工科背景下分析化学实验室开放共享新模式的探索*

通过分析实验室仪器设备开放共享管理现状,阐述了当前存在的主要问题,进而提出了“动静结合”“虚实结合”的开放共享新模式,并提出了完善管理制度、合理优化资源、加强实验人才队伍建设以及运用数字化平台等一系列管理对策。     

最小化碳排放的共享单车迁移问题

本文考虑共享单车迁移问题, 它可看作是经典旅行售货商问题的一个新颖变形, 不同的是其目标函数为最小化碳排放。其中, 碳排放利用单车负载与其行驶路程的乘积进行刻画。我们提出了两个启发式算法：贪心和基于TSP的算法, 每个算法的核心思想均是优先减少单车负载。从理论上证明算法的可行性并给出数据实验以验证算法的实际性能。数据实验结果表明贪心算法优于基于TSP的算法, 这为共享单车企业进行日常单车分配提供了理论依据。     

Conversion of waste meat to resources by enzymatic reaction under high pressure carbon dioxide conditions

ABSTRACT

Every year, a tremendous amount of meat is wasted, which may have adverse effects on the environment. Therefore, waste meat should be recycled. Building a recycling system for waste meat to reduce financial loss and careful treatment of life-based resources is essential. As meat contains abundant amino acids, it can be used as an immense source of amino acids for other industries following enzymatic hydrolysis. However, during the enzymatic hydrolysis process, the waste meat can easily get contaminated by microbes and therefore needs high temperature. In the present study, we applied high pressure carbon dioxide (HPCD) technology to prevent the contamination of meat by microbes during enzymatic hydrolysis process. According to our research, HPCD has a great potential to be adopted as a novel decontamination technology in the industrial enzymatic hydrolysis process at relatively lower temperature.