Chick chorioallantoic membrane as an in situ biological membrane for pharmaceutical formulation development: a review

The use of animals in research has always been a debatable issue. Over the past few decades, efforts have been made to reduce, replace, and refine experiments for ethical use of experimental animals. The use of chick chorioallantoic membrane (CAM) was one of the proposed alternatives to the Draize rabbit ocular irritation test with several advantages including simplicity, rapidity, sensitivity, ease of performance, and cost-effectiveness. The recent use of CAM in the development of pharmaceuticals and testing models to mimic human tissue, including drug transport across CAM, will be discussed in this review.     

利用鸡胚模型半体内评价多孔磷酸钙骨修复材料血管化的研究

利用鸡胚绒毛尿囊膜(CAM)中丰富的血管建立半体内模型, 研究多孔磷酸钙骨修复材料的血管化。将多孔羟基磷灰石陶瓷(HA)和具有部分孔隙结构的磷酸钙骨水泥(CPCs)分别植入CAM中共培养, 利用体式显微镜和扫描电子显微镜(SEM)观察CPCs表面血管的生长, 并利用Image-Pro Plus和Nano Measurer定量血管密度、直径和数量; 对CAM中培养的HA采用不脱钙组织学处理和观察。体式显微镜观察及定量结果显示多孔结构对血管生长影响显著, 随着培养时间延长, 多孔部分血管密度和数量均有明显增加, 而无孔部分血管生长缓慢。CPCs表面血管以出芽方式生长, 形成血管网络, 直径一般小于50 μm。SEM观察显示血管紧贴CPCs表面生长。苏木精-伊红(H&E)染色显示血管通过孔隙结构长入HA内部。实验结果说明三维孔隙结构利于血管的生长和长入, 此实验可简便、高效、低成本地研究多孔磷酸钙骨修复材料的血管化, 为快速评价生物材料血管化寻找一种新途径。     

Process planning for reliable high-speed machining of moulds

A method of generating NC programs for the high-speed milling of moulds is investigated. Forging dies and injection moulds, whether plastic or aluminium, have a complex surface geometry. In addition they are made of steels of hardness as much as 30 or even 50 HRC. Since 1995, high-speed machining has been much adopted by the die-making industry, which with this technology can reduce its use of Sinking Electrodischarge Machining (SEDM). EDM, in general, calls for longer machining times. The use of high-speed machining makes it necessary to redefine the preliminary stages of the process. In addition, it affects the methodology employed in the generation of NC programs, which requires the use of high-level CAM software. The aim is to generate error-free programs that make use of optimum cutting strategies in the interest of productivity and surface quality. The final result is a more reliable manufacturing process. There are two risks in the use of high-speed milling on hardened steels. One of these is tool breakage, which may be very costly and may furthermore entail marks on the workpiece. The other is collisions between the tool and the workpiece or fixtures, the result of which may be damage to the ceramic bearings in the spindles. In order to minimize these risks it is necessary that new control and optimization steps be included in the CAM methodology. There are three things that the firm adopting high-speed methods should do. It should redefine its process engineering, it should systematize access by its CAM programmers to high-speed knowhow, and it should take up the use of process simulation tools. In the latter case, it will be very advantageous to use tools for the estimation of cutting forces. The new work methods proposed in this article have made it possible to introduce high speed milling (HSM) into the die industry. Examples are given of how the technique has been applied with CAM programming re-engineered as here proposed, with an explanation of the novel features and the results.     

Bibliometric analysis of complementary and alternative medicine research over three decades

This study applies bibliometric analysis to investigate the quantity and citation impact of scientific papers in the field of complementary and alternative medicine (CAM). The data are collected from 19 CAM journals in the Science Citation Index Expanded (SCI-E) database during 1980–2009, and 17,002 papers are identified for analysis. The study analyzes the document types, geographical and institutional distribution of the authorship, including international scientific collaboration. This study suggests that the major type of document is original article. The CAM papers are mostly published by North America, East Asia, and European countries, of which publications authored in East Asia are cited most. Country-wise, major contributors of CAM papers are from USA, People’s Republic of China, India, England and Germany. India has the highest CPP value, attracting high attentions in CAM community. This article also finds that international co-authorship in the CAM field has increased rapidly during this period. In addition, internationally collaborated publications generate higher citation impact than papers published by authors from single country. Finally, the research identifies productive institutions in CAM, and China Medical University located in Taiwan is the most productive organization.     

Comparative study of pharmacokinetic parameters between clarithromycin and erythromycin stearate in relation to their physicochemical properties

Pharmacokinetic parameters for clarithromycin (CAM) and erythromycin stearate (EMS) were obtained from a model including decomposition in the gastrointestinal tract. To confirm the accuracy of the parameters, various physicochemical properties of both drugs were examined. The ratio of the in vivo dissolution rate, the in vivo decomposition rate and the absorption rate between CAM and EMS were well correlated to the ratio of the in vitro intrinsic dissolution rate, the decomposition rate in the acidic solution, and partition coefficient, respectively. One of the reasons for the excellent absorption of CAM compared with that of EMS was the higher stability in the acidic solution and the higher partition coefficient of CAM. These findings indicate that the ratio of the partition coefficient to the decomposition rate constant in acidic solution plays an important role in determining drug bioavailability for macrolide antibiotics.     

Automatic set-up planning for metal cutting: an integrated methodology

Automatic set-up planning has been regarded as a challenging task in computer-aided process planning (CAPP), which is a critical link in the integration of computer-aided design (CAD) and computer-aided manufacturing (CAM). Solving this problem is a top priority for CAD/CAM researchers and developers. Many researchers have worked on the problem and proposed different solutions based on geometry analysis, precedence constraint analysis, kinematic analysis, force analysis and tolerance analysis. However, these solutions generally use an ad hoc approach rather than a systematic approach. Consequently, the solutions can sometimes be impractical. An integrated methodology is presented to generate set-ups and select set-up datums and to determine set-up sequence. The methodology can deal successfully with a variety of components, thus providing a practical solution to the set-up planning problem that is crucial to the metal cutting industry.     

Electrochemo-mechanical effects as a critical design factor for all-solid-state batteries

All-solid-state batteries (ASSBs) using inorganic solid electrolytes (SEs) are in the spotlight for next-generation energy storage devices because of their potential for outstanding safety and high energy density. Recent progress in this field has been primarily based on advances in materials, such as the discovery of SEs with high ionic conductivities and the improvement of interfacial stability in electrodes. However, the use of inelastic SEs causes severe electrochemo-mechanical failures, such as cathode active material (CAM) disintegration, CAM/SE contact loss, and stress build-up during cycling, deteriorating the Li⁺ and e^? transport pathways. Although these concerns have been addressed previously, they have not been contextualized systematically in terms of the mechanical interactions among the components and their impacts on electrochemical performance. Here, we categorize the electrochemo-mechanical effect in ASSBs and its ramifications in terms of stress sources, active materials, composite electrodes, and cell stacks.     

A proposed methodology for the global study of the mechanical properties of cold asphalt mixtures

Despite having been used for decades, the structural performance of emulsion-treated materials has still not been investigated as intensely as in the case of hot-mix asphalt (HMA). Proof of this is the lack of evolution of specific technical tests and standards. Due to this, many studies with cold asphalt mixtures (CAM) are carried out based on HMA specifications. Throughout the present paper, a new methodology is proposed in order to study different mechanical properties of CAM, such as unconfined compression strength (UCS), indirect tensile strength (ITS) and indirect tensile stiffness modulus (ITSM) not only in an independent way but also by giving a global approach. The consistency and applicability of the method is discussed and from its application to a practical case study with two very different CAM, new conclusions about their performance are laid down.     

Membrane fouling and alternative techniques for its alleviation

Concentration polarisation, cake formation and pore fouling lead to a performance loss in microfiltration membranes that manifests itself as a permeate flux reduction. Causes of these phenomena are varied and depend largely on components and properties of the feed suspension. The most common causes are summarised in this article. Techniques to limit this reduction or retard fouling are overviewed, including feed pretreatment, choice of membrane material, flow manipulation, the use of high shear, gas sparging and additional force fields.     

复杂零件数控编程KBE系统广义知识库应用研究

在分析数控编程KBE系统各模块相互联系的基础上,构建了基于KBE的复杂零件数控编程系统功能架构和广义知识库结构模型．综合数据库技术和知识库理论,建立了数控编程广义知识库系统．阐述了广义知识库的设计思想,给出了数控编程广义知识库与UG CAD／CAM应用接口实现的技术路线．并以企业需求为背景,在知识驱动型制造平台（UG CAD／CAM）上,利用VC＋＋6．0和UG／Open,将广义知识库系统和UGCAD／CAM无缝集成,实现了KBE和UG CAD／CAM系统的融合,开发了复杂零件数控编程KBE系统,验证了课题研究的可行性和实用性．     

CALCULATION OF THE DRIVING FORCE AND Ms FOR MARTENSITIC TRANSFORMATION IN Fe-C ALLOYS FROM THE CENTRAL ATOMS MODEL

根据已发表的活度数据,重新讨论了Fe-C 合金中心原子模型(CAM)中的热力学参数。利用中心原子模型计算了Fe-C 合金的马氏体相变驱动力和M_s。计算结果表明,碳含量较低时,Fe-C 合金马氏体相变驱动力与碳含量成线性递增关系。根据计算结果和徐模型推算了Fe-C 合金奥氏体在M_s点的强度。M_s 的计算与实验结果符合得较好。由CAM 模型得到:M_s(K)=834-8277x_c     

In-Memory Computing with Memristor Content Addressable Memories for Pattern Matching

The dramatic rise of data-intensive workloads has revived application-specific computational hardware for continuing speed and power improvements, frequently achieved by limiting data movement and implementing “in-memory computation”. However, conventional complementary metal oxide semiconductor (CMOS) circuit designs can still suffer low power efficiency, motivating designs leveraging nonvolatile resistive random access memory (ReRAM), and with many studies focusing on crossbar circuit architectures. Another circuit primitive—content addressable memory (CAM)—shows great promise for mapping a diverse range of computational models for in-memory computation, with recent ReRAM–CAM designs proposed but few experimentally demonstrated. Here, programming and control of memristors across an 86 × 12 memristor ternary CAM (TCAM) array integrated with CMOS are demonstrated, and parameter tradeoffs for optimizing speed and search margin are evaluated. In addition to smaller area, this memristor TCAM results in significantly lower power due to very low programmable conductance states, motivating CAM use in a wider range of computational applications than conventional TCAMs are confined to today. Finally, the first experimental demonstration of two computational models in memristor TCAM arrays is reported: regular expression matching in a finite state machine for network security intrusion detection and definable inexact pattern matching in a Levenshtein automata for genomic sequencing.     

基于精确边界提取的纸盒排样CAN系统

纸盒排样系统是纸盒CAD/CAM系统的重要组成部分之一,排样的好坏直接影响系统的整体性能.介绍了纸盒排样系统的总体设计和一些关键技术,提出了有效地针对纸盒排样的预处理方案和排样算法.该系统已经实现并已投入实际的生产应用.     

基于环球网的CAD/CAM技术

提出了开发基于Ｉｎｔｅｒｎｅｔ（中文意为环球网）的ＣＡＤ／ＣＡＭ系统的思想，并利用Ｉｎｅｔｅｒｎｅｔ中应用最普遍的ＷＷＷ服务中的上应网关接口成功地开发了基于Ｉｎｔｅｒｎｅｔ的ＣＡＤ／ＣＡＭ系统。     

Applications of crack analogy to fretting fatigue

In literature the most common approach to investigate fretting fatigue is based on contact mechanics. Crack initiation parameters of fretting fatigue are developed using elastic solution of two contacting bodies. Even though contact based parameters has been used extensively, they could not fully capture crack initiation mechanism due to the complexities of the fretting fatigue damage process, which depends on pad geometries, surface properties, material properties, and mechanical loading conditions. This has instigated fretting fatigue researcher to investigate other approaches. Recently, taking advantage of the similarities between contact mechanics and fracture mechanics lead to the development of crack analogy methodology (CAM), which defines the stress intensity factor as a fretting fatigue crack initiation parameter. CAM has shown a great potential investigating fretting fatigue. However, it has not been applied to wide range of fretting fatigue scenarios. The scope of this paper is not to focus on analytical development of CAM as much as validating its ability to analyze various fretting fatigue scenarios. Based on CAM, the present study introduces the crack analogy fretting parameter (CAF-parameter) to investigate crack initiation of fretting fatigue, which is equivalent to the change of mode II stress intensity factor at the contact surface, since the change in the stress intensity factor reflects the cyclic mechanism of fatigue. Further, a modification to the CAM is adopted to include various indenter-substrate geometries. Also, CAF-parameter-life curve, similar to the stress-life S-N curve, will be developed as a prediction tool to crack initiation for various geometric configurations using experimental data. This is consistent with presenting fatigue data. The results show similar pattern to plain fatigue with lower damage tolerance. It also shows scatter and dependency on the pad configuration as expected. Finally, the CAF-parameter shows potentials in effectively analyzing/predicting the complex mechanism of fretting fatigue.     

Integrated and concurrent approach for compound sheet metal cutting and punching

In sheet metal processing and manufacturing, there are a lot of small- and medium-sized job shops. These small- and medium-sized manufacturing companies have been facing keen competitive pressure in the market. This pressure has forced these companies to make every effort to shorten product development lead-time, improve production efficiency, approach high-quality standards, but at the same time cut down the costs. To meet the needs of these companies, this paper presents a compound cutting and punching production method supported by an integrated CAD/CAPP/CAM system in sheet metal manufacturing. Many existing commercial CAD/CAM systems are not suitable for this manufacturing method, especially under concurrent and global design and manufacturing environments. Some problems have to be solved before these CAD/CAM systems can be employed and integrated for this compound manufacturing method. This paper deals mainly with the solutions to solve some of these problems. The solutions include an integrated data integration platform based on Pro/INTRALINK and STEP, and a knowledge-based real time CAPP (RTCAPP) system for compound sheet metal cutting and punching. Within the presented CAD/CAPP/CAM system, some key modules have been developed. They are the automatic tool selection and manufacturing sequencing module, a shortest tool path optimization module, a cost estimation module and an automatic insertion of auxiliary path module based on knowledge bases. These modules will be addressed here.     

Publication activity in complementary and alternative medicine

In this article we analyse how research on complementary and alternative medicine (CAM) break through into one established scientific arena, namely academic journals. With help from bibliometric methods we analyse publication of CAM articles, in the Medline database, during the period 1966–2007. We also analyse the general content of the articles and in what journals they get published. We conclude that the publication activity of CAM articles increases rapidly, especially in the late 1990s, and that the changing growth rate is not due to the general expansion of Medline. The character of CAM articles has changed towards more clinical oriented research, especially in subfields such as acupuncture and musculoskeletal manipulations. CAM articles are found both in core clinical journals and in specialized CAM journals. Even though a substantial part of the articles are published in CAM journals, we conclude that the increasing publication activity is not restricted to the expansion of these specialized journals.     

Interaction mechanism of cement and asphalt emulsion in asphalt emulsion mixtures

The interaction characteristics of cement asphalt composite mastic (CAM) and performance properties of cement asphalt emulsion mixtures (CAEM) were evaluated in this work using chemical and mechanical test methods to investigate the effect of the presence of cement on asphalt emulsion mixtures (AEM). The chemical composition of the CAM was obtained through use of X-ray diffraction, Fourier-transform infrared spectroscopy, and environmental scanning electron microscopy (ESEM) as a means to describe the interactions between the cement and asphalt in the composite materials. Test results demonstrated that cement can hydrate with the water phase of the asphalt emulsion. Asphalt droplets can simultaneously enclose cement particles and delay the hydration reaction process of cement. The interaction mechanism of cement particles or hydration products and residual asphalt is a physical compound process. The influence of these findings on asphalt emulsion mixture design and performance properties was assessed using varying mix design components and conducting laboratory-based mechanical test methods for rutting resistance and moisture susceptibility. Mix design components varied including added water content, emulsion content, and cement dosage levels. The optimum fluids content was determined based on the dry indirect tensile strength. It was found that the cement content significantly impacts the optimum fluids content for both added water and emulsion. Furthermore, the presence of cement improves the dry tensile strength, rutting resistance, and moisture susceptibility. Based on microstructural analysis of CAM and CAEM, the mechanism by which cement improves the performance of AEM is attributed to the ability of hydration products to increase both the stiffness of the asphalt binder and the adhesion at the mastic–aggregate interface. In practical applications, this study recommends a mix design method for cement-modified asphalt emulsion mixes (CAEM) based on selection of optimum cement and emulsion contents using indirect tensile strength and verification of the design through evaluation of the moisture susceptibility and rutting resistance of the CAEM mix. Threshold values of CAEM mix mechanical properties to determine the quality of the design are proposed.     

CAD/CAPP/CAM集成系统的研究与开发

文章介绍了可实用的CAD/CAPP/CAM集成系统。该系统是由机械产品设计人员,工艺人员和数控机床NC编程人员共同努力,在商品CAD/CAM软件Pro/ENGINEER平台上开发的。系统由三个子系统组成：零件信息识别子系统,CAPP子系统和自动CAM子系统。零件信息识别子系统从三维零件中提取零件信息,CAPP子系统分析零件信息,自动生成零件加工工序和工步,从刀具数据库中查询刀具及切削用量,并完成各工序的工步排序。自动CAM子系统根据CAPP的结果,自动生成Pro/ENGINEER的NC工步,经过NC仿真后     

新型天然膜材料——甲壳质及其衍生物

甲壳质资源丰富,易化学修饰和成膜,是一种制备耐酸碱、耐热性能良好和具有极好生物相溶性膜的新型膜材料。本文详述了它在超滤、反渗透、渗透蒸发、透析膜、气体分离膜、离子交换膜、固定化酶膜及医学用膜的制备及应用。