Investigations into the molecular-level adhesion characteristics of hydroxyapatite-coated and anodized titanium surfaces using the molecular orbital approach

It has been established that the adhesion of cells on to the surfaces of orthopaedic implants depends on the ability of the surfaces to accommodate protein molecules. Hydroxyapatite coating and anodizing are the most common methods to make TiAl6V4 implants (Ti) more biocompatible. In this paper Spartan 02, a molecular dynamics software, is used to analyze and predict the bonding characteristics of Extra cellular matrix protein sequence arginine-glycine-aspartic acid (RGD) on a Hyrdoxyapatite (HA) coated Ti and an anodized Ti surface based on the property of its constituent atoms, their polarity (net electrostatic charge, Qr), the energies of the molecular orbital E_HOMO (energy of the highest occupied molecular orbital), and E_LUMO (energy of the lowest unoccupied molecular orbital). The results show favourable criterion for formation of bonding between the HOMO orbital of the HA coated and anodized surfaces and LUMO orbital of the glycine strand from the RGD unit. The mechanism of bonding of individual atoms to form primary calcium oxide compounds is likely only in the case of HA coated surfaces . The surface texture of the anodized Ti with inherent porosities appear more responsible for the adsorption of proteins on to them by mechanical interlocking than the formation of any intermediate calcium oxide compounds.     

An improved formalism for quantum computation based on geometric algebra—case study: Grover’s search algorithm

The Grover search algorithm is one of the two key algorithms in the field of quantum computing, and hence it is desirable to represent it in the simplest and most intuitive formalism possible. We show firstly, that Clifford’s geometric algebra, provides a significantly simpler representation than the conventional bra-ket notation, and secondly, that the basis defined by the states of maximum and minimum weight in the Grover search space, allows a simple visualization of the Grover search analogous to the precession of a spin- ${\frac{1}{2}}$ particle. Using this formalism we efficiently solve the exact search problem, as well as easily representing more general search situations. We do not claim the development of an improved algorithm, but show in a tutorial paper that geometric algebra provides extremely compact and elegant expressions with improved clarity for the Grover search algorithm. Being a key algorithm in quantum computing and one of the most studied, it forms an ideal basis for a tutorial on how to elucidate quantum operations in terms of geometric algebra—this is then of interest in extending the applicability of geometric algebra to more complicated problems in fields of quantum computing, quantum decision theory, and quantum information.     

善用双卡拓带宽3G无线上网提速小秘密

近来,无线上网提速受到很多朋友的关注,今天就让我们来深入的了解一下无线上网提速的魅力吧!虚拟服务器模拟,数据包过滤等等,全新等着你.     

花180美元 电视与电脑可无线连接

如果想把台式机或笔记本的好东东在你的HDTV上播放,你或许要选择一根很长的视频电线,但很多时候如果你的电脑不具备相应的端口来连接是一件很懊恼的事情,现在好了,只要一个Warpia的USB音频/视频适配器,就可实现电脑与电视的链接而不需连接线。     

省钱看阿凡达售价400元内电信3G无线上网卡

1联想CE200（参考价：350元） 联想CE2003G无线上网卡是2009年上半年推出的一款针对电信CDMA20003G网络的无线上网卡。联想CE200外形小巧、靓丽、时尚,乳白色外观与目前主流U盘类似。拥有多种颜色可供选择,大胆的采用了宝蓝色荧光漆面,彰显时代气息。艳丽的色泽使女性对其青睐有加,简洁的造型也颇受男士的欣赏。     

The effect of handle friction and inward or outward torque on maximum axial push force

OBJECTIVE: To investigate the relationship among friction, applied torque, and axial push force on cylindrical handles. BACKGROUND: We have earlier demonstrated that participants can exert greater contact force and torque in an "inward" movement of the hand about the long axis of a gripped cylinder (wrist flexion/forearm supination) than they can in an "outward" hand movement. METHOD: Twelve healthy participants exerted anteriorly directed maximum push forces along the long axis of aluminum and rubber handles while applying deliberate inward or outward torques, no torque (straight), and an unspecified (preferred) torque. RESULTS: Axial push force was 12% greater for the rubber handle than for the aluminum handle. Participants exerted mean torques of 1.1, 0.3, 2.5, and -2.0 Nm and axial push forces of 94, 85, 75, and 65 N for the preferred, straight, inward, and outward trials, respectively. Left to decide for themselves, participants tended to apply inward torques, which were associated with increased axial push forces. CONCLUSION: Axial push force was limited by hand-handle coupling--not the whole body's push strength. Participants appeared to intuitively know that the application of an inward torque would improve their maximum axial push force. Axial push forces were least when a deliberate torque was requested, probably because high levels of torque exertions interfered with the push. APPLICATION: A low-friction handle decreases maximum axial push force. It should be anticipated that people will apply inward torque during maximum axial push.     

无线路由器工作异常的三谜三解

在有线网络随处可见的日子里,无线局域网的"身影"正朝我们越走越近,大有与有线网络并驾齐驱的架势.     

解析无线网络弊病化解无线安全威胁

伴随着低档次无线网络设备的价格不断走低,以及操作上的越来越简便,低档次无线局域网网络在最近几年得到了快速普及.为了方便进行资源共享、无线打印、移动办公操作,我们只要耗费几百元钱购买一台普通的无线路由器和一块无线网卡设备,就可以快速地搭建好一个简易的无线局域网网络了.不过,低档次无线局域网网络的不断普及,也容易给单位的信息安全带来不小的威胁.在这种情形下,我们该如何才能化解低档次无线网络的安全威胁,享受组网的快捷、便利呢?     

Coupling agent-based models of subsistence farming with individual-based forest models and dynamic models of water distribution

Subsistence farming communities are dependent on the landscape to provide the resource base upon which their societies can be built. A key component of this is the role of climate and the feedback between rainfall, crop growth, land clearance and their coupling to the hydrological cycle. Temporal fluctuations in rainfall alter the spatial distribution of water availability, which in turn is mediated by soil-type, slope and landcover. This pattern ultimately determines the locations within the landscape that can support agriculture and controls sustainability of farming practices. The representation of such a system requires us to couple together the dynamics of human and ecological systems and landscape change, each of which constitutes a significant modelling challenge on its own. Here we present a proto-type coupled modelling system to simulate land-use change by bringing together three simple process models: (a) an agent-based model of subsistence farming; (b) an individual-based model of forest dynamics; and (c) a spatially explicit hydrological model which predicts distributed soil moisture and basin scale water fluxes. Using this modelling system we investigate how demographic changes influence deforestation and assess its impact on forest ecology, stream hydrology and changes in water availability.     

Digital Intuition: Applying Common Sense Using Dimensionality Reduction

Understanding the world we live in requires access to a large amount of background knowledge: the commonsense knowledge that most people have and most computer systems don't. Many of the limitations of artificial intelligence today relate to the problem of acquiring and understanding common sense. The Open Mind Common Sense project began to collect common sense from volunteers on the Internet starting in 2000. The collected information is converted to a semantic network called ConceptNet. Reducing the dimensionality of ConceptNet's graph structure gives a matrix representation called AnalogySpace, which reveals large-scale patterns in the data, smoothes over noise, and predicts new knowledge. Extending this work, we have created a method that uses singular value decomposition to aid in the integration of systems or representations. This technique, called blending, can be harnessed to find and exploit correlations between different resources, enabling commonsense reasoning over a broader domain.