Formulation and development of ophthalmic in situ gel for the treatment ocular inflammation and infection using application of quality by design concept

Context: The conventional liquid ophthalmic delivery systems exhibit short pre-corneal residence time and the relative impermeability to the cornea which leads to poor ocular bioavailability.

Objective: The aim of this study was to apply quality by design (QbD) for development of dexamethasone sodium phosphate (DSP) and tobramycin sulfate (TS)-loaded thermoresponsive ophthalmic in situ gel containing Poloxamer 407 and hydroxyl propyl methyl cellulose (HPMC) K4M for prolonging the pre-corneal residence time, ocular bioavability and decreases the frequency of administration of dosage form. The material attributes and the critical quality attributes (CQA) of the in situ gel were identified. Central composite design (CCD) was adopted to optimize the formulation.

Materials and methods: The ophthalmic in situ forming gels were prepared by cold method. Materials attributes were the amount of Poloxamer 407 and HPMC and CQA identified were Gel strength, mucoadhesive index, gelation temperature and % of drug release of both drug.

Results and discussion: Optimized batch (F*) containing 16.75% poloxamer 407 and 0.54% HPMC K4M were exhibited all results in acceptable limits. Compared with the marketed formulation, optimized in situ gel showed delayed T_max, improved C_max and AUC in rabbit aqueous humor, suggesting the sustained drug release and better corneal penetration and absorption.

Conclusion: According to the study, it could be concluded that DSP and TS would be successfully formulated as in situ gelling mucoadhesive system for the treatment of steroid responsive eye infections with the properties of sustained drug release, prolonged ocular retention and improved corneal penetration.     

Analysis and evaluation of a general camera model

A versatile General Camera Model, GCM, has been developed, and is described in detail. The model is general in the sense that it can capture both fisheye and conventional as well as catadioptric cameras in a unified framework. The camera model includes efficient handling of non-central cameras as well as compensations for decentring distortion. A novel way of analysing radial distortion functions of camera models leads to a straightforward improvement of conventional models with respect to generality, accuracy and simplicity. Different camera models are experimentally compared for two cameras with conventional and fisheye lenses, and the results show that the overall performance is favourable for the GCM.     

基于CAS集群的单点失效问题解决方案

单点登录(SSO)可以消除多个应用服务系统之间的重复认证过程,但会加重认证负载,引起单点失效的风险,导致服务中断。针对上述问题,提出具有集群功能的单点登录系统,将用户登录请求分发到不同的单点登录服务器,解决单个单点登录服务器负担过重的问题,增强系统运行的稳定性。     

基于多Agent的医疗信任模型的模拟

结合直接交互信任评价和第三方信誉推荐,提出了一种基于多Agent技术的医疗信任模拟模型。使用置信因子来综合直接交互信任值和第三方信誉推荐值;避免了患者直接交互的盲目性和巨额计算,完善了对医生自我推荐的辨别能力。实验采用Swarm仿真平台模拟医疗信任模型的交互过程,结果表明该模型在确定信任关系中相对IT模型要快,比第三方信誉推荐模型相对要可靠。     

A high-order non-oscillatory central scheme with non-staggered grids for hyperbolic conservation laws

In this work, we present a scheme which is based on non-staggered grids. This scheme is a new family of non-staggered central schemes for hyperbolic conservation laws. Motivation of this work is a staggered central scheme recently introduced by A.A.I. Peer et al. [A new fourth-order non-oscillatory central scheme for hyperbolic conservation laws, Appl. Numer. Math. 58 (2008) 674–688]. The most important properties of the technique developed in the current paper are simplicity, high-resolution and avoiding the use of staggered grids and hence is simpler to implement in frameworks which involve complex geometries and boundary conditions. Numerical implementation of the new scheme is carried out on the scalar conservation laws with linear, non-linear flux and systems of hyperbolic conservation laws. The numerical results confirm the expected accuracy and high-resolution properties of the scheme.     

基于空间共线点的单光心反射折射摄像机标定

一条空间直线的单光心反射折射图像是一个二次曲线段, 大多数利用直线进行单光心反射折射摄像机标定的方法都需要对直线的像进行二次曲线拟合, 曲线拟合的精度严重影响着标定的精度. 然而, 一条空间直线的像仅占整个二次曲线的一小段, 这使得曲线拟合的效果非常差. 本文利用空间三个共线点的反射折射投影给出了摄像机内参数的一个非线性约束. 当反射镜面为抛物面时, 在主点已知的情况下, 该约束变为线性约束. 如其他参数已知, 该约束变为关于有效焦距的多项式约束. 由此, 本文提出了三种不同条件下的标定算法, 算法中无需对直线的像进行二次曲线拟合, 无需场景的任何信息, 标定精度较高. 实验验证了算法的有效性.     

Irrigation infrastructure development in the Limarí Basin in Central Chile: implications for adaptation to climate variability and climate change

One option to deal with climate variability in agriculture is to build irrigation infrastructure, although this may lead to the overdevelopment of water resources, leading to ‘basin closure’. The Limarí Basin, in central north Chile, has relied on irrigation infrastructure over the last 30 years to increase water supply reliability and extend irrigated acreage, especially for permanent crops. This situation has reduced adaptation opportunities in the basin, which is currently experiencing a severe drought that, according to climate change projections, is expected to persist in the future, with important consequences for the sustainability of agriculture production.     

浅谈新疆某水库闸门集中控制系统

新疆某水库泄洪闸门集控系统是以美国Wonderware公司的Intouch 10.1系统监控软件为开发平台所建立的一套集远程监控和远程操作为一体的闸门控制系统。该系统上位机通过局域网与各闸门控制系统的PLC进行通讯,包括上送各种信息和接受控制命令,通讯采用标准以太网,支持TCP/IP协议,系统建立于2011年6月,经过1年多的操作运行,情况良好。     

中部地区清洁发展机制（CDM）项目发展状况与问题分析

清洁发展机制是《京都议定书》创建的三种灵活机制之一,其目标是可持续发展与环境完整性。我国政府十分重视清洁发展机制的运用与发展。文章从通过国家发改委审批、执行理事会（EB）注册和GER签发三个阶段数据,对中部地区目前CDM项目发展现状及存在问题进行剖析,并提出发展建议。     

论河南当代文学旅游价值的开发策略

河南有着悠久的历史文化积淀,文学旅游资源丰厚,但近年来对河南文学旅游资源的开发和利用,一直比较滞后。必须利用河南当代文学蕴含的场景、民俗和接受等资源,以当代作家为依托,以他们的作品为平台,加大作家资源及作品民俗资源的挖掘,打造河南文化旅游形象,开发河南当代文学的旅游价值。