The Influence of Lactose Pseudopolymorphic Form on Salbutamol Sulfate–Lactose Interactions in DPI Formulations

A series of 63- to 90-μm sieve-fractioned lactose pseudopolymorphs were investigated in terms of carrier functionality for dry powder inhaler (DPI) formulations. Stable α-anhydrous, α-monohydrate, and β-anhydrous were chosen as model pseudopolymorphs. In addition, the β-anhydrous was further purified to remove residual α-monohydrate content (β-treated). The carriers were investigated in terms of morphology, particle size, crystallinity, and surface energy using inverse gas chromatography. Furthermore, the lactose samples carrier performance was evaluated by studying the aerosolization efficiency of the model drug, micronized salbutamol sulfate, from drug–carrier blends using a next generation impactor (NGI). In general, the aerosol performance of drug from carrier followed the rank order α-monohydrate?>?β-anhydrous?>?β-treated?>?α-anhydrous. Significant difference in carrier size was observed, specifically with relation to the amount of fines (where a rank order of β-treated?>?β-anhydrous?>?α-monohydrate?>?α-anhydrous. No direct relationship between fine content and particle morphology was observed. In comparison, an inverse relationship between surface energy and aerosolization efficiency was found, where a plot of fine particle fraction (aerodynamic diameter < 4.46?μm) against total surface energy resulted in R²?=?.977. Such observations are most likely due to increased particle carrier adhesion and reduced drug liberation during the aerosolization process, indicating surface chemistry (in this case due to the existence of different pseudopolymorphs) to play a dominating role in DPI systems.     

Spray Drying of Aqueous Salbutamol Sulfate Solutions Using the Nano Spray Dryer B-90—The Impact of Process Parameters on Particle Size

In order to prepare spherical salbutamol sulfate particles of adjustable size, a Nano Spray Dryer B-90 was employed. A 3³ full-factorial design was used to investigate the influence of process parameters (mesh size, feed concentration, and drying air temperature) on particle size (median size and width of the particle size distribution), amount of product produced per time, and product yield. The median particle size was significantly influenced by all three factors of the statistical design. Within the design space studied, particle sizes of 1.0 to 6.4 µm were obtained. The width of the particle size distribution (span) increased with increasing mesh sizes. All particles with a particle size greater than 2.4 µm showed a bimodal particle size distribution. Generally, larger mesh sizes as well as higher concentrations led to an increase in the amount of product prepared per time. The corresponding values observed were from 0.4 to 75.8 mg/min. The product yield was independent of the process parameters studied. All products were amorphous after spray drying and were stable up to a relative humidity of 60% at a temperature of 25°C.     

面向轻载深包检测的应用负载特征自动挖掘(英文)

Automatic signature generation approaches have been widely applied in recent traffic classification.However,they are not suitable for LightWeight Deep Packet Inspection(LW_DPI) since their generated signatures are matched through a search of the entire application data.On the basis of LW_DPI schemes,we present two Hierarchical Clustering(HC) algorithms:HC_TCP and HC_UDP,which can generate byte signatures from TCP and UDP packet payloads respectively.In particular,HC_TCP and HC_ UDP can extract the positions of byte signatures in packet payloads.Further,in order to deal with the case in which byte signatures cannot be derived,we develop an algorithm for generating bit signatures.Compared with the LASER algorithm and Suffix Tree(ST)-based algorithm,the proposed algorithms are better in terms of both classification accuracy and speed.Moreover,the experimental results indicate that,as long as the application-protocol header exists,it is possible to automatically derive reliable and accurate signatures combined with their positions in packet payloads.     

带宽管理技术在P2P业务控制中的应用研究

本文在介绍带宽管理技术需求变化的基础上,研究了典型的带宽管理技术原理和特点,主要包括DPI和DFI技术,然后对目前运营商利用带宽管理技术对网络上P2P等业务进行控制的应用情况做了分析.     

主动声纳直达波干扰抑制的盲分离算法

针对舰艇编队作战中主动声纳之间存在的强直达波干扰,提出了一种基于信号统计二阶矩的直达波干扰抑制算法,实现了强干扰背景下的微弱目标回波检测。这种方法将盲分离理论和匹配相关技术相结合,首先对接收数据进行直达波干扰抑制,再利用已知发射信号副本进行匹配相关,最后提取目标回波信号。相比其它强干扰抑制算法,特别是高阶累计量法,该算法具有计算复杂度低的优点。通过数值仿真实验表明：该算法能够对直达波干扰进行有效抑制,对目标回波的检测性能优于直接匹配相关方法。     

基于智能会话关联的腾讯语音流量识别算法

通过实验分析了国内流行的即时通信软件——腾讯QQ的流量特征以及其语音会话的流量特征,应用净荷深度检测(DPI)和智能会话关联(ISA)技术来识别腾讯语音通话流量,设计了腾讯语音业务流量的识别模型和算法。模型和算法的准确性、可扩展性和健壮性在电信运营商IP骨干网中得到了验证。     

基于数据流前端检测的快速协议识别

信息战都追求高速反应机动,对网络协议识别提出了高效快速的要求。基于深度包检测DPI的协议识别方法识别准确率高,但是由于要对所有数据包进行检测,计算量很大。基于端口号的协议识别方法速度快,但识别准确率低。提出一种新的基于数据流前端检测的协议识别方法并进行了系统实现,结合了基于端口方法的快速简单和基于DPI的准确性的优点。实验表明,这种综合快速协议识别方法识别准确率高,与基于DPI的方法相比,识别时间减少将近80%。     

一种双核SoC调试系统的设计与验证

调试系统的设计和验证是多核SoC设计中的重要环节。基于某双核SoC的设计,提出一个片上硬件调试构架,利用FPGA构建该调试系统的硬件验证平台。双核SoC调试系统验证平台利用System Verilog DPI,将RealView调试器、Keil C51及目标芯片的验证testbench集成在一起,实现了双核SoC调试系统的RTL级调试验证。利用该平台,在RTL仿真验证阶段可方便地对ARM和8051核构成的双核SoC进行调试,解决仿真中出现的问题,从而有效缩短设计周期,并提高验证效率。该双核SoC调试系统验证平台的实现对其他系统芯片设计具有一定的参考价值。     

局域网下的P2P流媒体直播性能优化方案

随着P2P实时流媒体在网络上的流行,来自P2P实时流媒体应用的流量占据了在ISP主干链路的流量中相当大的比例.对于种类繁多并且私有化了应用层协议的P2P流媒体应用来说,目前很少有针对性的方法在不损害用户播放效果的前提下来缓解其对主干网的流量压力.通过对目前主流的基于Mesh结构的P2P流媒体直播系统工作原理的分析,提出一套基于应用层协议的针对局域网用户的P2P实时流媒体优化方案,能够从整体上有效减少P2P流媒体应用对该局域网外部节点的依赖,同时从下载效率以及播放延时等方面改善该局域网内部的P2P流媒体服务的用户体验.实验结果表明,在局域网内具有一定数量的P2P实时流媒体用户以及相对集中的节目源的情况下,该方案在改善网络流量和用户体验方面均能起到很好的效果.