Nanotechnology‐Enabled Closed Loop Insulin Delivery Device: In Vitro and In Vivo Evaluation of Glucose‐Regulated Insulin Release for Diabetes Control

Recently, a new multifunctional, bio‐inorganic nanocomposite membrane with the ability to self‐regulate the release of insulin in response to blood glucose (BG) levels was reported. Herein, the application of this material as part of a small, implantable, closed‐loop insulin delivery device designed to continuously monitor BG concentrations and regulate insulin release is proposed. The insulin delivery device consists of a nanocomposite glucose‐responsive plug covalently bound to an insulin reservoir made of surface‐modified silicone. The plug is prepared with crosslinked bovine serum albumin (BSA) and enzymes (glucose oxidase (GOx) and catalase (CAT)), pH‐responsive hydrogel nanoparticles, and multifunctional MnO₂ nanoparticles. The plug functions both as a glucose sensor and controlled delivery unit to release higher rates of insulin from the reservoir in response to hyperglycemic BG levels and basal insulin rates at normal BG concentration. The surfaces of the device are modified by silanization followed by PEGylation to ensure its safety and biocompatibility and the stability of encased insulin. Our results show that insulin release can be modulated in vitro in response to glucose concentrations. In vivo experiments show that the glycemia of diabetic rats can be controlled with implantation of the prototype device. The glucose‐responsiveness of the device is also demonstrated by rapid drop in BG level after challenging diabetic rats with bolus injection of glucose solution. In addition, it is demonstrated that surface PEGylation of the device is necessary for reducing the immune response of the host to the implanted foreign object and maintaining insulin stability and bioactivity. With this molecular architecture and the bio‐inorganic nanocomposite plug, the device has the ability to maintain normal BG levels in diabetic rats.     

一种基于VME总线双余度容错处理系统的设计与实现

VME总线是具有高可靠性的并行总线,在机载嵌入式系统领域受到广泛应用。文章首先对VME总线结构进行了分析,然后描述了用双机数据处理系统的组成与工作原理,最后重点说明了双机数据处理系统VME总线接口逻辑与系统容错设计方法。     

Electronic Structure and Optoelectronic Properties of Bismuth Oxyiodide Robust against Percent‐Level Iodine‐, Oxygen‐, and Bismuth‐Related Surface Defects

In the search for nontoxic alternatives to lead‐halide perovskites, bismuth oxyiodide (BiOI) has emerged as a promising contender. BiOI is air‐stable for over three months, demonstrates promising early‐stage photovoltaic performance and, importantly, is predicted from calculations to tolerate vacancy and antisite defects. Here, whether BiOI tolerates point defects is experimentally investigated. BiOI thin films are annealed at a low temperature of 100 °C under vacuum (25 Pa absolute pressure). There is a relative reduction in the surface atomic fraction of iodine by over 40%, reduction in the surface bismuth fraction by over 5%, and an increase in the surface oxygen fraction by over 45%. Unexpectedly, the Bi 4f_7/2 core level position, Fermi level position, and valence band density of states of BiOI are not significantly changed. Further, the charge‐carrier lifetime, photoluminescence intensity, and the performance of the vacuum‐annealed BiOI films in solar cells remain unchanged. The results show BiOI to be electronically and optoelectronically robust to percent‐level changes in surface composition. However, from photoinduced current transient spectroscopy measurements, it is found that the as‐grown BiOI films have deep traps located ≈0.3 and 0.6 eV from the band edge. These traps limit the charge‐carrier lifetimes of BiOI, and future improvements in the performance of BiOI photovoltaics will need to focus on identifying their origin. Nevertheless, these deep traps are three to four orders of magnitude less concentrated than the surface point defects induced through vacuum annealing. The charge‐carrier lifetimes of the BiOI films are also orders of magnitude longer than if these surface defects were recombination active. This work therefore shows BiOI to be robust against processing conditions that lead to percent‐level iodine‐, bismuth‐, and oxygen‐related surface defects. This will simplify and reduce the cost of fabricating BiOI‐based electronic devices, and stands in contrast to the defect‐sensitivity of traditional covalent semiconductors.     

基于法拉第旋光效应的葡萄糖浓度传感研究

本文主要研究葡萄糖、葡萄糖氧化酶(GOD)以及两者的混合溶液的法拉第磁致旋光效应,为基于法拉第旋光效应的葡萄糖传感器提供了理论依据,研究介质的旋光特性,可以更好地提升光电传感器的性能,更广泛地应用光电传感器.在法拉第磁致旋光效应中,当介质处于磁场中时,平面偏振光透过该介质时,偏振面会旋转一个角度.将不同浓度的溶液置于磁...     

激光泵浦受电容残压影响及容限分析

分析了激光泵浦系统中储能电容残压的产生原因,并通过长期试验研究,给出了电容残压的产生和增长规律。综合考虑电容残压增长规律和激光装备实际应用情况,明确提出了激光装备的实际残压容限值和维修决策原则;并依据电容残压增长规律和激光器泵浦氙灯工作特性,指出调高储能电容工作电压是一种不仅无益而且有损于激光装备工作寿命的维修方法。     

The effects of PMD and PDL on the performance of OOK and DPSK systems

Using multiple importance sampling （MIS） technique, the optical communication system performance affected by polarization-mode dispersion （PMD） and polarization-dependent loss （PDL） is simulated numerically. The power penalties and system outage probabilities are obtained for optical communication systems with on-off keying （OOK） or differential phase shift keying （DPSK） modulation. The simulation results show that DPSK always performs better than OOK. When the system has moderate PDL （about 1.5 dB）, it is necessary to compensate effectively the fiber PMD in order to enhance the system tolerance to the PMD and PDL. However, the efficiency of PMD compensation will degrade rapidly when the PMD of the whole optical link drops into the low value.     

Disruption tolerant networking by Smart Caching

Future mobile radio networks will aim at achieving ‘broadband access for all’, anywhere. The performance of a radio network vitally depends on the characteristics of the transmission path between the user terminal and the access point and the degree of network coverage. In urban areas, full broadband radio coverage is difficult to provide, causing a high variation in the link quality and making broadband services hard to realize. In rural regions, massive deployment costs prevent a full broadband coverage. Most of the time users have to settle for UMTS‐like wide area networks. For mobile users accessing services, such as video streaming, which require continuous broadband connectivity, it virtually results in intermittent network connectivity. The frequent disruption of the broadband link and its replacement with no or only low‐performance connections is a problem that should be addressed. This article introduces a new technique called Smart Caching (SC), which is able to mitigate variations in the network performance so that non‐real‐time and non‐interactive services' quality is substantially improved. SC supports pre‐fetching from a server and buffering data at the edge of the core network, in the so‐called Smart Cache. It transmits data with extremely high speed to be buffered in the mobile terminal when it is in the service range of an access point. This allows for the provisioning of data‐intensive services even in the case of patchy wireless broadband network coverage and intermittent connectivity. The performance of the SC service is evaluated with two different sophisticated queuing models, both based on the Markov arrival process. The benefit of the new technique is discussed and dimensioning issues are outlined. Furthermore, a comparison with legacy network setups is given. Copyright © 2009 John Wiley & Sons, Ltd.     

射频指纹识别系统的数学模型研究

构建了基本的射频指纹识别系统模型;把无线发射机电子元件的制造容差与漂移容差统一为“元件容差”,把无线发射机电子元件的实际值建模为在“元件容差”内的随机变量,把无线发射机基带至识别系统接收机基带部分建模为时不变稳定系统,建立了基本射频指纹识别系统模型的数学模型;基于所建数学模型分析了射频指纹的唯一性。     

基于中间件的入侵容忍体系结构研究

分析了入侵容忍模型和MAFTIA体系结构及其中间件,将入侵容忍策略应用在中间件的执行过程中,保证不同系统之间具有相同的安全策略.在中间件层实现了基于门限密码技术的密钥管理服务,使得参与者只能拥有一定数量的密钥份额才能恢复密钥进行解密,防止恶意参与者的攻击行为,有效地保护了系统中信息的机密性与完整性.     

基于内存分块相异数据的虚拟机同步机制

定量分析了不同应用程序的内存分块数据相异部分,即某一阶段的内存有效改动页面分块与其他未变化内存分块的数据相异数据比例,提出基于内存数据相异部分的虚拟机同步机制,主虚拟机端通过基于地址和内容的散列函数表寻找与Dirty内存页面分块的最优匹配Non-dirty页面分块,相异数据通过XOR压缩后通过网络发送给备份虚拟机;备份虚拟机解码接收到的同步数据,重组在主虚拟机端的Dirty内存页面,从而完成备份虚拟机的状态同步操作。实验结果表明,与传统的标准异步方式相比,基于内存分块相异数据的虚拟机同步机制可以减少80%左右的同步操作带来的网络通信数据量,大大提高了某些基准测试程序的系统性能。