bluuebunny/crossref_metadata_2025 huggingface dataset:
HIGH PERFORMANCE MAC UNIT USING MODIFIED SIGN EXTENSION ALGORITHM AND A NEW HIGH-SPEED ALU IN DSP-CORE
Authors: YAO JUN , CHEN JIE , LIN ZHAOJUN
Published: May 2005

This paper describes a high performance multiply-accumulator (MAC) unit in DSP-core. Since the most critical timing path of the DSP lies in the MAC, great endeavors have been paid to speed it up. The MAC unit can perform fixed-point operation with rounding optional, on operands with a throughput of 1 cycle. In this design, the modified sign extension algorithm is presented to eliminate the sign bits array of partial products to reduce computation time and area. Further increase in speed is achieved by using a new three 40 bit inputs (also known as operands) high-speed arithmetic logical unit (ALU) to shorten the delay of the critical path.
AN EVALUATION OF MODEL-BASED SOFTWARE SYNTHESIS FROM SIMULINK MODELS FOR EMBEDDED VIDEO APPLICATIONS
Authors: DOBLANDER ANDREAS , GÖSSERINGER DIETMAR , RINNER BERNHARD , SCHWABACH HELMUT
Published: May 2005

In next generation video surveillance systems there is a trend towards embedded solutions. Digital signal processors (DSP) are often used to provide the necessary computing power. The limited resources impose significant challenges for software development. Resource constraints must be met while facing increasing application complexity and pressing time-to-market demands. Recent advances in synthesis tools for Simulink suggest a high-level approach to algorithm implementation for embedded DSP systems. The model-based visual development process of Simulink facilitates simulation as well as synthesis of target specific code. In this work the modeling and code generation capabilities of Simulink are evaluated with respect to video analysis algorithms. Different models of a motion detection algorithm are used to synthesize code. The generated code targeted at a Texas Instruments TMS320C6416 DSP is compared to a hand-optimized reference. Experiments show that an ad hoc approach to synthesize complex image processing algorithms hardly yields optimal code for DSPs. However, several optimizations can be applied to improve performance.
VERIFICATION OF EMBEDDED SUPERVISORY CONTROLLERS CONSIDERING HYBRID PLANT DYNAMICS
Authors: ENGELL SEBASTIAN , LOHMANN SVEN , STURSBERG OLAF
Published: May 2005

This contribution proposes a link between the specification of supervisory controllers by Sequential Function Charts (SFC) and the verification of embedded systems with hybrid dynamics. The SFC are transformed into modular timed automata using a procedure based on graph grammars. The resulting controller model is composed with a hybrid automaton (with possibly nonlinear continuous dynamics) that models the plant behavior. In order to verify safety properties of the composed system algorithmically, a tool implementing the recently proposed approach of counterexample guided model checking is employed. The procedure is illustrated for a processing system example.
DSP-BASED MOTION CONTROL OF A NON-COMMUTATED DC LINEAR MOTOR MODULE
Authors: LI H. Z. , GONG Z. , LIN W. , JIANG T. Y. , CHEN X. Q.
Published: May 2005

This paper presents the development of a digital signal processor (DSP) based motion controller for a linear servo motor system. The linear motor system employs a moving magnet non-commutated DC linear servo motor as the actuator, and a linear variable differential transformer (LVDT) as the position feedback transducer. It is ideal for short stroke, high accuracy and high speed closed loop servo applications. The controller hardware is based on a TI TMS320LF2407A DSP. The system architecture and motion control strategies are presented. An index motion is implemented using this system. The experimental results with discussions are also given.
MULTI-KEY INDEX FOR DISTRIBUTED DATABASE SYSTEM
Authors: HOSAIN MD. SHAZZAD , NEWTON MUHAMMAD ABDUL HAKIM
Published: May 2005

In this paper we present a multi-key index model that enables us to search a record with more than one attribute values in distributed database systems. Indices provide fast and efficient access of data and so become a major aspect in centralized database systems. Most of the centralized database systems use B + tree or other types of index structures such as bit vector, graph structure, grid file etc. But in distributed database systems no index model is found in the literature. Therefore efficient access is a major problem in distributed databases. Our proposed index model avoids the query-flooding problem of existing system and thus optimizes network bandwidth.
METHOD OF INTERACTION IN A MODULAR ARCHITECTURE FOR SENSOR SYSTEMS (MASS)
Authors: DAVIS JESSE , STARK DOUGLAS , EDMONDS NICHOLAS
Published: May 2005

The system level hardware architecture of individual nodes in a distributed wireless sensor network has not received adequate attention. A novel hardware architecture based on the concept of task specific modular computing provides both the high flexibility and power efficiency required for effective distributed sensing solutions. This paper presents this newly developed architecture and provides an analysis of two possible methods for module interaction. Results from simulations based on this analysis are given. Finally, a brief description of the hardware and software design and prototype implementation of the modular architecture for sensor systems (MASS) is given to show the ease of use of the conceptual architecture.
MULTI-CHANNEL BIOTELEMETRY SYSTEM USING MICROCONTROLLER WITH UHF TRANSMIT FUNCTION
Authors: XU GUOLIN , TAY FRANCIS E. H. , ILIESCU CIPRIAN , SAMPER VICTOR
Published: May 2005

This paper presents the development of a three-channel telemetry system using Microchip rfPIC12F675 as transmitter and using rfRXD0420 as receiver. The highly integrated radio frequency IC chip features the system which is simple in structure, compact in size and low in power consumption. Using 3V power supply for the transmitter, the system is able to transmit low amplitude signal from 8 m to more than 50 m with power consumption as low as 10 mW. The biotelemetry system can be used in human or animal bio-signal acquisition and monitoring.
MADD OPERATION AWARE REDUNDANCY ELIMINATION
Authors: WU HAI P. , HU ZIANG , MANZANO JOSEPH , GAO GUANG R.
Published: May 2005

On general purpose computer architectures, the optimization of redundancy elimination almost always improves the cycle count. We argue that a specific consideration should be taken when applying this optimization to embedded architectures that feature multiply-add(MADD) instruction. This paper presents a redundancy elimination algorithm with MADD operation aware consideration. It produces optimized results for both code size and cycle count. The algorithm is integrated into KylinC compiler, a compiler for embedded systems developed at the University of Delaware. Experimental results demonstrate that the cycle counts of the benchmark programs are reduced on average 8% and the code sizes are reduced on average 5.27%.
A HYBRID ELASTIC NET METHOD FOR SOLVING THE TRAVELING SALESMAN PROBLEM
Authors: ZHANG WENDONG , BAI YANPING
Published: May 2005

The purpose of this paper is to present a new hybrid Elastic Net (EN) algorithm, by integrating the ideas of the Self Organization Map (SOM) and the strategy of the gradient ascent into the EN algorithm. The new hybrid algorithm has two phases: an EN phase based on SOM and a gradient ascent phase. We acquired the EN phase based on SOM by analyzing the weight between a city and its converging and non-converging nodes at the limit when the EN algorithm produces a tour. Once the EN phase based on SOM stuck in local minima, the gradient ascent algorithm attempts to fill up the valley by modifying parameters in a gradient ascent direction of the energy function. These two phases are repeated until the EN gets out of local minima and produces the short or better tour through cities. We test the algorithm on a set of TSP. For all instances, the algorithm is showed to be capable of escaping from the EN local minima and producing more meaningful tour than the EN.
SMART SHIRT THAT CAN CALL FOR HELP AFTER A FALL
Authors: TAY FRANCIS E. H. , NYAN MYO NAING , KOH TECK HONG , SEAH K. H. W. , SITOH YIH YIOW
Published: May 2005

A smart shirt was developed for geriatric healthcare purposes. It can summon medical assistances via SMS and e-mail when its bearer has fallen. Single axis accelerometers are arranged in medio-lateral, vertical and antero-posterior direction on the shoulder part of the shirt. Using Bluetooth™ transmitter/receiver, signals are transmitted and processed on a Personal Computer (PC) for fall-detection. Upon detection of falls, SMS (Short Messaging Service) and e-mail are sent through GSM (Global System for Mobile Communication) network supported by a local telecommunication service provider. The primary advantage of our detection system compared to other researchers' systems is that fall notification can be sent to individuals and medical health care unit simultaneously to lead to a shortened interval of the arrival of assistance.
AN EMBEDDED SYSTEM TO SUPPORT TELE-MEDICAL ACTIVITY
Authors: NG JIA HUI , TAN CHAUR LIH , HA YA JUN
Published: May 2005

Tele-medical systems have proven to be very useful to improve patient outcomes. However, they suffered from drawbacks such as insufficient functionality, prohibitive cost, the lack of connectivity and many other factors. To solve these problems, medical experts were consulted and an embedded tele-medical system was developed that allows a doctor to analyze and predict the ailment of a patient and direct the paramedic on the scene to perform potentially life-saving corrective actions or even promote recovery. The system would capture, process and interpret ECG data from the patient using the low cost hardware which was designed.
MODELING AND MOTION CONTROL OF ROBOTIC HAND FOR TELEMANIPULATION APPLICATION
Authors: LOW K. H. , WANG HENG , LIEW KIM MEOW , CAI YIYU
Published: May 2005

This paper presents the process of a motion control system design and implementation for a teleminulation system. The robotic manipulator/hand is a nonlinear system with coupled effects among the joints. By applying the frequency response method, the nonlinear system is modeled as decoupled linear ones, in which each joint is controlled independently. The experimental results show the feasibility of the modeling process. Based on the obtained transfer function of each joint, the digital PID controllers are designed. The motion control system for the telemanipulation system is then implemented using the software package MATLAB, Simulink, Real Time Workshop, xPC Target and a C/C++ compiler, and the hardware I/O boards, amplifiers, etc. The presented developing procedure shows a convenient way to implement a real time robotic control system.
DESIGN ANALYSIS OF THE PROPULSION AND CONTROL SYSTEM OF AN UNDERACTUATED REMOTELY OPERATED VEHICLE USING AXIOMATIC DESIGN THEORY — PART 2
Authors: KOH T. H. , TAY F. E. H. , LAU M. W. S. , LOW E. , SEET G.
Published: May 2005

In this paper, Axiomatic Design (AD) theory was adopted for the design analysis of an underactuated Remotely Operated Vehicle (ROV) system and its subcomponents. The system design issues of the Propulsion and Control System of the ROV II are analyzed and addressed based on the Independence Axiom methodology. The top-level Functional Requirements (FRs) for the thruster design and configuration are identified and its corresponding Design Parameters (DPs) are also presented.
HIGH-SPEED RT MONITORING SYSTEM USING NEURAL NETWORKS
Authors: MARZI HOSEIN
Published: May 2005

This paper describes a high-speed reconfigurable neural networks for monitoring operational status of automated machinery. Continuous operation of precision machines may change their system performance due to wear, deterioration, or failure. A Learning Vector Quantization (LVQ) based technique is developed that is capable of monitoring system status accurately, and updating its knowledge base with new heuristic data. This method is adapted for practical application to solve problems of condition monitoring and fault diagnosis where a number of fault signatures are initially available. In these situations, the aim is health monitoring, including identification of deterioration of the healthy condition and identification of causes of the failures. A hard real-time system is designed and implemented. An early-warning system monitors sensitive parameters of pressure and current sensors. Their variations beyond a defined healthy threshold trigger a non-destructive testing, which produces transient signals. Correlating the transient pattern of a fault with a database of known failures determines the severity and degree of deterioration of the system. Vigorous tests on real machines indicated an accuracy of 92.3% for the LVQ based monitoring system.
DESIGN OF 3-VALUED R-S & D FLIP-FLOPS BASED ON SIMPLE TERNARY GATES
Authors: DHANDE A. P. , INGOLE V. T.
Published: May 2005

Design of 3-valued R-S & D type of flip-flops is described. A new clock is developed according to which circuit makes transition as well as retains present, past & former past information. The proposed flip-flops are constructed using clocked T-Gates that reduces the number of transistors required to implement single clocked gates. In the verification by simulation, the proposed flip-flops appears to have lesser power consumption and better speed of operation.
TOWARDS PERVASIVE ROBOTICS: COMPLIANT MOTION IN HUMAN ENVIRONMENTS
Authors: ANG MARCELO H.
Published: May 2005

Robotics research and development span over five decades but is still not pervasive in our daily lives. This paper attempts to explain why and reviews compliant motion which is a crucial capability required to make robots pervasive. Robotic tasks are analyzed and algorithms for control of compliant motion of manipulators are presented.
MICROCONTROLLER BASED LIGHT CONTROL
Authors: UDDIN MOHAMMED RAFIQ , MAEEN -UR- RASHID GAZI , ISLAM MD. SHAHIDUL
Published: May 2005

A microcontroller-based control system is a direct outgrowth of the extensive advances in the Integrated Circuit design and microelectronic device processing technology. This has led to the development of new forms of technologies. This paper presents a technique of microcontroller based control system for controlling the lights of a room. Using the technique, according to the intensity of the sunlight in a room, the states of light of that room will change. Therefore we need to collect data or information from the environment using light sensors to control lights. The microcontroller collects the information from the atmosphere and changes the state of different lights. The analog data collected by the sensors are converted to digital form by an Analog to Digital Converter (ADC) and then fed to the microcontroller. The output data stream of the microcontroller is in digital form by which analog device lights will be controlled.
LILLIPUTIAN HARDWARE PLATFORM FOR SCIENTIFIC APPLICATIONS
Authors: IYER NEELIMA , KHATAVKAR RUPALI , JOSHI BHAGYASHREE , UPADHYE VIKRAM
Published: May 2005

Microcontroller plays an important role in gearing up scientific applications for measurements, data acquisition and controls. With the advent of technology in microcontrollers, a new era in the form of microconverter is available at the user's doorstep. Benefited by the excellent features of Analog Devices' microconverter chip ADuC 842, an attempt has been made to develop a Lilliputian platform for scientific applications at National Chemical Laboratory (NCL), Pune. A real time system has been developed for measuring surface tension exerted by Langmuir films formed at air water interface. The films are compressed by smooth and precision barrier mechanism through DC motor in a controlled manner. I 2 C compatible EEPROM is provided on board for data storage and it can be communicated to a PC through RS232 link for further analysis. The other features provided are, In-circuit programming for firmware updating, keyboard functioning for special routine executions, I 2 C compatible RTC and battery backup. The software has been completely developed using assembly language programming. Intelligent Lilliputian platform designed using ADuC 842 chip and graphic LCD for real time plotting of surface pressure area isotherm of Langmuir films has been developed and tested successfully at NCL.
CASE STUDIES IN THE HYBRID PROCESS ALGEBRA HyPA
Authors: MAN K. L. , RENIERS M. A. , CUIJPERS P. J. L.
Published: May 2005

HyPA is an algebraic theory based on the classical process algebra Algebra of Communicating Processes (ACP) for the specification and analysis of hybrid systems. We have the idea that HyPA is also well suited for addressing various aspects of digital embedded systems including hardware, software and concurrency, as well as mixed-signal designs. To show that HyPA is useful for the specification and analysis of hybrid systems and that our idea is correct, we illustrate the use of HyPA with some case studies: a point-to-point communication , a thermostat, a positive-edge-triggered D flip flop, and a small part of a mixed-signal fuzzy controller.
Relation-Based Information Retrieval
Authors: Manjula D. , Geetha T. V.
Published: May 2005

The traditional Boolean word-based approach to information retrieval (IR) considers only words for indexing. Irrelevant information is retrieved because of non-inclusion of semantic information like word senses and word context. In this work, the importance of representing the documents along another semantic dimension in addition to sense context information is considered. The incorporation of semantic relations as an additional dimension gives a better insight into the interpretation of the document. The micro-contexts generated from the documents are also used in indexing. The retrieval performance is measured in terms of precision and recall. The results tabulated show better performance.
Comparative Analysis of Commercial Knowledge Management Solutions and their Role in Enterprises
Authors: Janev Valentina , Vraneš Sanja
Published: May 2005

Knowledge technologies are a subject of permanent interest for software engineers at research organisations, as well as for market analysts in commercial organisations. In this paper, which aims to clarify the role of knowledge management solutions in an enterprise business, we survey the market of commercial knowledge management solutions and analyse their functionalities in domains such as document management, information retrieval, collaboration, decision support, e-learning, business automation and enterprise integration. The survey is based on a thorough study of web resources of knowledge management solution providers. Regarding the role of knowledge solutions in the business process, the present study will show that on an operational level they serve for better utilisation of the enterprise knowledge resources and, on a strategic level, they synthesise new knowledge needed for better management of customers, suppliers and partners. This paper gives an insight into the knowledge management market that can help strategic planners to easily begin a knowledge management initiative.
Knowledge Management: Case Studies in SMEs and Evaluation of an Integrated Approach
Authors: Wong Kuan Yew , Aspinwall Elaine
Published: May 2005

To date, very few publications have been found that describe how small and medium enterprises (SMEs) are adopting knowledge management (KM). The same is true concerning attempts to develop a framework to help them implement it. To redress this, this paper presents the results of four case studies conducted in UK SMEs to examine their KM implementation effort. In addition, a new integrated framework developed by the authors was evaluated to determine its applicability in this business sector. The methodology employed to conduct the studies is described and each of the cases is then presented. The results are analysed and key lessons or findings gathered from the companies are highlighted. Comments received from the companies with respect to the integrated framework were positive and favourable. It is hoped that the information accrued from the case studies, together with the integrated framework, will help to pave the way for SMEs to accomplish KM.
A Scalable Classification Algorithm for Very Large Datasets
Authors: Delen Dursun , Kletke Marilyn G. , Kim Jin-Hwa
Published: May 2005

Today's organisations are collecting and storing massive amounts of data from their customer transactions and e-commerce/e-business applications. Many classification algorithms are not scalable to work effectively and efficiently with these very large datasets. This study constructs a new scalable classification algorithm (referred to in this manuscript as Iterative Refinement Algorithm, or IRA in short) that builds domain knowledge from very large datasets using an iterative inductive learning mechanism. Unlike existing algorithms that build the complete domain knowledge from a dataset all at once, IRA builds the initial domain knowledge from a subset of the available data and then iteratively improves, sharpens and polishes it using the chucks from the remaining data. Performance testing of IRA on two datasets (one with approximately five million records for a binary classification problem and another with approximately 600 K records for a seven-class classification problem) resulted in more accurate domain knowledge as compared to other prediction methods including logistic regression, discriminant analysis, neural networks, C5, CART and CHAID. Unlike other classification algorithms whose performance and accuracy deteriorate as data size increases, the efficacy of IRA improves as datasets become significantly larger.
PRIORITY DECISION OF KEY TECHNOLOGY ELEMENT IN NEW PRODUCT DEVELOPMENT: AN EMPIRICAL COMPARISON BETWEEN QFD AND TAGUCHI METHOD
Authors: YANG JONG-SEO , YUN MYUNG-HWAN
Published: May 2005

Technology innovation or new product development (NPD) is composed of various process elements that require specialized knowledge/know-how needed for the application of fundamental technologies on actual product development. With the widespread use of techniques such as PERT/CPM, a major part of project management efforts focuses on resource allocation and time scheduling. In a multi-project environment of high-technology product development, prioritizing technology elements within a full spectrum of required developments is relatively more important than resource allocation or cost-reduction. Furthermore, disagreements between project managers and researchers in setting the priorities of project elements should be resolved and managed systematically to leverage a successful execution of the whole project.

In this study, modified QFD and modified Taguchi method are suggested for setting priorities among elemental technologies. As a first step, the authors interviewed project managers from two companies in order to identify elemental technologies and competitiveness factors of the project in scope. Then, the priorities of elemental technologies for both projects are measured using two different methods. In the modified QFD method, the relationship matrix (HOQ, house of quality) is used to determine the priorities. In the modified Taguchi method, the priorities are determined by evaluating contributions of each elemental technology on competitiveness factors with participant's opinions as noise variables. The results of the two methods are compared. A post-hoc survey showed that project managers and researchers slightly prefer the QFD method.
BOSTON ROUTE 128 REVISITED
Authors: WONGLIMPIYARAT JARUNEE
Published: May 2005

The paper revisits the success case of Boston Route 128 in commercializing technology. The study applies the concept of industrial clusters to explain the development of technologically sophisticated region of Boston Route 128. Boston Route 128 has transformed its structure from the minicomputer and microprocessor-based technology industry in the 1980s to biotechnology industry in the late 1990s and 2000s. It is argued that the successful commercialization process of Boston Route 128 is rooted in innovation, entrepreneurial management and the policy towards technology commercialization. To consider the argument, the paper proposes the cluster model to explain the strengths of Boston Route 128 in biotech clusters. It represents a model of the universities working with industries to form a cluster of high technology based firms. The venture capital accelerates the process of technology commercialization, giving rise to a new Boston model of innovation management. Policy makers may use the Boston model as a benchmark to evaluate their performance in supporting Hi-Tech industries.
INTER-FIRM PRODUCT PLATFORM DEVELOPMENT IN THE AUTOMOTIVE INDUSTRY
Authors: LUNDBÄCK MAGNUS , KARLSSON CHRISTER
Published: May 2005

The product platform development process becomes critical and of general interest when different brand name products are developed from inter-firm developed product platforms. The inter-firm platform adds perspectives not considered in previous research. In this article areas related to the inter-firm product platform integration process are described. The study is a longitudinal, deep, explorative study aimed at identifying managerial challenges to inter-firm platform development and how they can be dealt with. Analysis shows that the factory sequence is a critical factor when developing inter-firm platform architecture. Also, making architectural concessions without jeopardising brand uniqueness places new demands on managers involved in the development processes. Further, we found a reciprocal interdependence between technological and managerial factors that created a need for innovative organisational and managerial solutions. Finally, reciprocal interdependences add complementary theoretical knowledge on how to better control and understand areas that hamper inter-firm product development projects from attaining cost-effective solutions and economies of scale.
AN EMPIRICAL STUDY ON THE CONSTRUCTION OF A MODEL FOR MEASURING ORGANISATIONAL INNOVATION IN TAIWANESE HIGH-TECH ENTERPRISES
Authors: LIU CHUN-CHU
Published: May 2005

The objective of this research was to construct organisational innovation dimensions and the associated evaluation index for Taiwan's high-tech industries, in order to evaluate Taiwan's current level of ability in this area, and provide a guideline for businesses. In addition, an organisational innovation model was also constructed to serve as a basis for innovation theory. The research methods employed included a literature review, in-depth interviews and small group techniques, which were used as a first step towards constructing an organisational innovation measurement model. Before constructing the organisational innovation measurement model for the present study, a weighted measurement index was created by means of an analytic hierarchy process, multivariate analysis of variance and factor analysis, in order to confirm the index and the organisational innovation cause and effect relationship. After the organisational innovation model was constructed, the empirical study concluded that the most important dimensions for measuring organisational innovation included product innovation, process innovation and organisational structure and climate innovation.
PIERRE BOURDIEU AND THE PRACTICES OF LANGUAGE
Authors: Hanks William F.
Published: May 2005

This paper synthesizes research on linguistic practice and critically examines the legacy of Pierre Bourdieu from the perspective of linguistic anthropology. Bourdieu wrote widely about language and linguistics, but his most far reaching engagement with the topic is in his use of linguistic reasoning to elaborate broader sociological concepts including habitus, field, standardization, legitimacy, censorship, and symbolic power. The paper examines and relates habitus and field in detail, tracing the former to the work of Erwin Panofsky and the latter to structuralist discourse semantics. The principles of relative autonomy, boundedness, homology, and embedding apply to fields and their linkage to habitus. Authority, censorship, and euphemism are traced to the field, and symbolic power is related to misrecognition. And last, this chapter relates recent work in linguistic anthropology to practice and indicates lines for future research.
THE PATTERNS OF NATURAL VARIATION IN HUMAN GENES
Authors: Crawford Dana C. , Akey Dayna T. , Nickerson Deborah A.
Published: May 2005

▪ Abstract  Currently, more than 10 million DNA sequence variations have been uncovered in the human genome. The most detailed variation discovery efforts have focused on candidate genes involved in cardiovascular disease or in susceptibilities associated with exposure to environmental agents. Here we provide an overview of natural genetic variation from the literature and in 510 human candidate genes resequenced for variation discovery. The average human gene contains 126 biallelic polymorphisms, 46 of which are common (≥5% minor allele frequency) and 5 of which are found in coding regions. Using this complete picture of genetic diversity, we explore conservation, signatures of selection, and historical recombination to mine information useful for candidate gene association studies. In general, we find that the patterns of human gene variation suggest that no one approach will be appropriate for genetic association studies across all genes. Therefore, many different approaches may be required to identify the elusive genotypes associated with common human phenotypes.
Receptive Field Size and Response Latency Are Correlated Within the Cat Visual Thalamus
Authors: Weng Chong , Yeh Chun-I , Stoelzel Carl R. , Alonso Jose-Manuel
Published: May 2005

Each point in visual space is encoded at the level of the thalamus by a group of neighboring cells with overlapping receptive fields. Here we show that the receptive fields of these cells differ in size and response latency but not at random. We have found that in the cat lateral geniculate nucleus (LGN) the receptive field size and response latency of neighboring neurons are significantly correlated: the larger the receptive field, the faster the response to visual stimuli. This correlation is widespread in LGN. It is found in groups of cells belonging to the same type (e.g., Y cells), and of different types (i.e., X and Y), within a specific layer or across different layers. These results indicate that the inputs from the multiple geniculate afferents that converge onto a cortical cell (approximately 30) are likely to arrive in a sequence determined by the receptive field size of the geniculate afferents. Recent studies have shown that the peak of the spatial frequency tuning of a cortical cell shifts toward higher frequencies as the response progresses in time. Our results are consistent with the idea that these shifts in spatial frequency tuning arise from differences in the response time course of the thalamic inputs.
Computational Modeling Suggests That Response Properties Rather Than Spatial Position Determine Connectivity Between Olfactory Glomeruli
Authors: Linster Christiane , Sachse Silke , Galizia C. Giovanni
Published: May 2005

Olfactory responses require the representation of high-dimensional olfactory stimuli within the constraints of two-dimensional neural networks. We used a computational model of the honeybee antennal lobe to test how inhibitory interactions in the antennal lobe should be organized to best reproduce the experimentally measured input-output function in this structure. Our simulations show that a functionally organized inhibitory network, as opposed to an anatomically or all-to-all organized inhibitory network, best reproduces the input-output function of the antennal lobe observed with calcium imaging. In this network, inhibition between each pair of glomeruli was proportional to the similarity of their odor-response profiles. We conclude that contrast enhancement between odorants in the honeybee antennal lobe is best achieved when interglomerular inhibition is organized based on glomerular odor response profiles rather than on anatomical neighborhood relations.
A Randomized, Double-Blind, Double-Dummy, Safety Crossover Trial Comparing Cumulative Doses up to 96 μg of Formoterol Delivered via an HFA-134a-Propelled pMDI vs. Same Cumulative Doses of Formoterol DPI and Placebo in Asthmatic Patients
Authors: Molimard M. , Guenolé E. , Duvauchelle T. , Vicaut E. , Lefrançois G.
Published: May 2005

Background: Formoterol’s effects on the cardiovascular system are well known, but whether these effects are altered by the reformulation of inhalers to replace CFC propellants with HFA propellants is not. Objectives: To evaluate the effect of cumulative doses up to 96 µg of formoterol delivered via an HFA-134a-propelled pMDI, on cardiac safety and the QTc interval, compared the same cumulative doses delivered via a DPI, in adult patients with moderate-to-severe asthma. Methods: This study was a multicenter, double-blind, double-dummy, placebo-controlled, three-period, crossover trial in which 22 patients with moderate-to-severe asthma received cumulative doses up to 96 µg of formoterol (12 + 12 + 24 + 48 µg) delivered via a pMDI or a dry power inhaler (DPI). Vital signs and fourteen 12-lead ECG measurements were taken at each clinic visit and at 5–10 days after the final drug administration. Results: An increase from baseline in QTc interval was observed with all formoterol treatment arms in a dose-dependent manner. The maximum increases were 56.3, 62.6 and 25.0 ms for the formoterol pMDI, formoterol DPI and placebo treatments, respectively. Heart rate was increased by 10.7, 14.9 and 6.5 bpm in the pMDI, DPI and placebo groups, respectively. Both formoterol treatments were also associated with a decrease in diastolic blood pressure compared with placebo. Conclusions: With respect to cardiovascular safety parameters, the administration of formoterol via a pMDI device is comparable to its delivery via a DPI.
Bronchoprotective and Bronchodilator Effects of an HFA pMDI vs. a CFC pMDI and a DPI Containing Formoterol in Asthma Patients
Authors: Langley S.J. , Houghton C.M. , Singh S.D.
Published: May 2005

In this double-blind, placebo-controlled, crossover study we compared the bronchoprotective effects of formoterol 12 µg inhaled via an HFA-134a inhaler (Modulite® HFA) versus a CFC and a DPI device in 38 patients with mild-to-moderate persistent asthma. All three formoterol preparations significantly increased methacholine PD20 and FEV1 and improved small airway function parameters compared with placebo (p < 0.001). No significant differences were observed between formoterol formulations. In conclusion, Modulite® HFA formoterol was found to be an effective and well tolerated treatment in patients with asthma, with comparable efficacy to current formoterol preparations.
Effect of Withdrawal of Fluoride-Containing Toothpaste on the Interproximal Plaque Microflora
Authors: Brailsford S.R. , Kidd E.A.M. , Gilbert S.C. , Clark D.T. , Beighton D.
Published: May 2005

To compare the effects of fluoride-containing and fluoride-free toothpaste on plaque microflora, 15 subjects were enrolled in a double-blind crossover trial. All subjects used a fluoride toothpaste for 7 days before the trial started. Then, 4 interproximal sites per subject were professionally cleaned and subjects used one of the toothpastes for 5 days. On the 5th day plaque was collected from 2 sites, 12 and 6 h after toothpaste use. There was no difference between the groups in the numbers or proportions of aciduric bacteria (recovered at pH 4.8 or 5.2), or of yeasts, neisseriae, lactobacilli or streptococci (total or individual species, including Streptococcus mutans). However, the numbers and proportions of Gram-positive pleomorphic rods, primarily Actinomyces naeslundii, increased in 6-hour samples from subjects using fluoride toothpaste. The data suggest that the anti-caries effect of fluoride toothpaste is not mediated primarily through effects on the plaque microflora, although effects on plaque physiology could be important.
Effect of a Calcium Carbonate-Based Dentifrice on in situ Enamel Remineralization
Authors: Cury J.A. , Simões G.S. , Del Bel Cury A.A. , Gonçalves N.C. , Tabchoury C.P.M.
Published: May 2005

This crossover study evaluated the effect of calcium carbonate (CaCO3)-based monofluorophosphate dentifrice on enamel remineralization. Ten volunteers wore palatal appliances containing four enamel blocks with caries-like lesions, two of them covered by a test plaque of mutans streptococci. The following treatments were evaluated: a negative control, a silica-based or a CaCO3-based dentifrice, and the percentage of enamel surface microhardness recovery was determined. The CaCO3-based dentifrice was more effective than the negative control on the enhancement of enamel remineralization, either in the presence or absence of test plaque. This efficacy was also shown by the silica-based dentifrice but only in the presence of test plaque.
Effect of Rinsing with Water Immediately after APF Gel Application on Enamel Demineralization in situ
Authors: Delbem A.C.B. , Carvalho L.P.R. , Morihisa R.K.U. , Cury J.A.
Published: May 2005

This double-blind crossover in situ study evaluated the effect of rinsing with water immediately after the application of acidulated phosphate fluoride (APF) on enamel demineralization. APF application was followed by: no rinsing or consuming of liquids or solids for the next 30 min; immediately washing with water jet or drinking of a glass of water. All treatments showed a statistically significant decrease in enamel mineral loss compared to the control (p < 0.05), but the differences among treatments were not significant (p > 0.05). The data suggest that the recommendation of asking patients to refrain from drinking water following professional APF application does not seem to have an influence on the anticaries effect of fluoride.
Comparison of Transepidermal Water Loss and Spectroscopic Absorbance to Quantify Changes of the Stratum corneum after Tape Stripping
Authors: Weigmann H.-J. , Ulrich J. , Schanzer S. , Jacobi U. , Schaefer H. , Sterry W. , Lademann J.
Published: May 2005

The objective and quantitative application of tape stripping in pharmaceutics and dermatopharmacokinetics requires the determination of the exact position of each removed tape strip inside the stratum corneum (SC) and/or the determination of the relative SC thickness. In this study, transepidermal water loss (TEWL) and the optical spectroscopic data of the corneocytes were measured simultaneously during the complete removal of the SC by tape stripping. The spectroscopic data quantitatively reflect the amount of corneocytes removed by the individual tape strips, whereas TEWL and 1/TEWL are not sensitive enough to measure the relatively small changes in the SC thickness realized by the removal of the individual strips. The relative SC thickness can be determined directly by the spectroscopic data, while the 1/TEWL values require a second independent method. The results demonstrate the importance of tape stripping characterizing the behaviour of topically applied substances.
Diabetes-Induced Renal Vascular Dysfunction Is Normalized by Inhibition of Epidermal Growth Factor Receptor Tyrosine Kinase
Authors: Benter Ibrahim F. , Yousif Mariam H.M. , Hollins Andrew J. , Griffiths Sioned M. , Akhtar Saghir
Published: May 2005

Contribution of receptor tyrosine kinase activation to development of diabetes-induced renal artery dysfunction is not known. We investigated the ability of a chronic administration of genistein, a broad-spectrum inhibitor of tyrosine kinases (TKs), and AG1478, a specific inhibitor of epidermal growth factor receptor (EGFR) TK activity, to modulate the altered vasoreactivity of isolated renal artery ring segments to common vasoconstrictors in streptozotocin-induced diabetes. In diabetic renal artery, the vasoconstrictor responses induced by norepinephrine, endothelin-1 and angiotensin II were significantly increased. Inhibition of TKs or the EGFR pathway did not affect the agonist-induced vasoconstrictor responses in the non-diabetic control animals. However, inhibition of TKs by genistein or EGFR TK by AG1478 treatment produced a significant normalization of the altered agonist-induced vasoconstrictor responses without affecting blood glucose levels. Treatment with diadzein, an inactive analogue of genistein, did not affect the vasoconstrictor responses in the diabetic animals. Western blotting showed that phosphorylated EGFR protein levels were increased in vehicle-treated diabetic animals. In renal arteries from AG1478-treated diabetic animals, EGFR protein levels were similar to non-diabetic control animals. These data suggest that activation of TK-mediated pathways, including the EGFR TK signalling pathway, are involved in the development of diabetic vascular dysfunction in the renal artery.
A Mouse Model of Aortic Angioplasty for Genomic Studies of Neointimal Hyperplasia
Authors: Petrov Lyubomir , Laurila Hanna , Häyry Pekka , Vamvakopoulos Joannis E.
Published: May 2005

We describe here a mouse model of diffuse aortic remodelling triggered by combined endothelial denudation/vascular distension injury using a novel balloon microcatheter. We validated this model in both outbred (NMRI) and inbred (BALB/c, C57BL/6) mouse strains and found evidence for differential strain susceptibility to neointimal hyperplasia, possibly attributable to genetic factors. Neointimal lesions were approximately 50% smaller in the inbred strains, a finding associated with profound cell loss in the aortic media at the early stages of the response to injury. A further insight from this model suggests an essential role for platelets in the initiation of neointimal hyperplasia, which apparently progresses through monocyte influx from the peripheral circulation. Our findings are consistent with monocyte recruitment driving neointimal growth, a minority expressing the endothelial cell marker FVIII. Overall, the time course and gross histological features of vascular remodelling seen here resemble those seen in other rodent models. However, this new mouse model offers distinct advantages over existing ones in that it involves the actual use of a catheter in a clinical manner, and because it allows the recovery of intact RNA from injured vessels in sufficient quantities for downstream molecular analyses.
Noninvasive Assessment of Local Pulse Pressure
Authors: Verbeke Francis , Segers Patrick , Heireman Steven , Vanholder Raymond , Verdonck Pascal , Van Bortel Luc M.
Published: May 2005

The advocated SphygmoCor procedure uses a radial-to-aorta transfer function with calibration on brachial instead of radial artery pressure to assess the central pulse pressure. We compared these values with carotid artery pulse pressures obtained from a validated calibration method, assuming mean minus diastolic blood pressure constant throughout the large artery tree. From 44 healthy subjects (21 males; 22 to 68 years) pressure waves were obtained at the radial, brachial, and carotid artery with applanation tonometry. Using the calibration method, radial and carotid artery pressures were assessed from brachial artery waves and pressures. The effect of brachial-to-radial pulse pressure amplification, brachial pulse pressure, mean pressure, age, gender, height, body mass index, and smoking on differences between the 2 methods was assessed. Brachial artery pressure was 118±12/72±10 mm Hg. SphygmoCor central pulse pressure was 9.7±4.6 mm Hg lower (
P
<0.001) than the carotid artery pulse pressure (33.0±6.8 versus 42.7±8.9 mm Hg). The difference between the 2 methods strongly depended (
P
<0.001) on brachial-to-radial artery pulse pressure amplification (5.8±5.1 mm Hg; 12±11%) and less on brachial artery pulse pressure (
P
=0.005). After calibration of the radial pressure wave with radial instead of brachial artery pressures, the difference between SphygmoCor central pulse pressure and carotid pulse pressure decreased with 4 mm Hg. The advocated SphygmoCor procedure systematically underestimates the central pulse pressure with brachial-to-radial pulse pressure amplification as important determinant. Therefore, calibration of radial artery pressure waves on brachial artery pressures should be avoided. The underestimation of central aortic pulse pressure caused by the radial-to-aorta transfer function itself is much less than previously reported.
Role of the Actin Cytoskeleton in G-Protein–Coupled Receptor Activation of PYK2 and Paxillin in Vascular Smooth Muscle
Authors: Ohanian Vasken , Gatfield Kelly , Ohanian Jacqueline
Published: May 2005

Dynamic remodeling of the actin cytoskeleton occurs during agonist-induced smooth muscle contraction. Tyrosine phosphorylation of the adaptor protein paxillin has been implicated in regulation of actin filament formation and force development. We have investigated the role of the actin cytoskeleton in noradrenaline (NA)-induced and endothelin (ET)-induced activation of the calcium-dependent nonreceptor tyrosine kinase PYK2 and subsequent phosphorylation of paxillin in rat small mesenteric arteries. NA and ET induced a rapid and prolonged activation of PYK2, as shown by increased phosphorylation at Y402 and Y881, and a concomitant association of the kinase with a Triton X-100 insoluble membrane (cytoskeleton) compartment. Both agonists also increased phosphorylation of paxillin at Y31 and Y118 with a similar time course as PYK2 phosphorylation, and induced its association with the same membrane compartment as PYK2. Treatment of arteries with cytochalasin D disrupted stress fibers and inhibited NA-induced and ET-induced force in a myosin light chain 20 phosphorylation independent and reversible manner. However, cytochalasin D treatment had no effect on NA-induced and ET-induced phosphorylation of either PYK2 or paxillin but did prevent their association with the TritonX-100 insoluble membrane compartment. These results show that in mesenteric arteries an intact cytoskeleton and force development are not prerequisites for G-protein–coupled receptor–induced activation of PYK2 and paxillin, by tyrosine phosphorylation, in vascular tissue, but are necessary for the translocation of PYK2 and paxillin to the membrane.
Vascular Development, Pulse Pressure, and the Mechanisms of Hypertension
Authors: Safar Michel E. , Boudier Harry Struijker
Published: May 2005

For a given cardiac function, the cyclic blood pressure (BP) curve results from 2 different phenotypes: the mean arterial pressure (MAP), a steady component reflecting the resistance of the microvascular network, and pulse pressure (PP), another component corresponding to large artery stiffness and wave reflections. Around birth, cardiovascular (CV) survival is critically influenced by the coupling between the heart and thoracic aorta, and hence, the adequacy of the Windkessel function, the magnitude of aortic elastin accumulation and the PP level. The maturation of the aortic trunk and its branches results from adaptative mechanisms involving shear and tensile stress, with major potential consequences on heart rate control, transit of wave reflections, and coronary perfusion. An adequate optimization of the Windkessel function, and hence PP, diastolic coronary perfusion and CV survival needs a critical MAP level to be reached in each individual during the postnatal period. The achievement of this MAP level requires the development of multiple resistance segments of the microvascular network, particularly within the kidney. Translated in adult populations, this pathophysiological process gives rise to a Gaussian BP distribution, with individuals remaining in the same BP percentile from birth onward (BP tracking). We suggest that hypertension results from early developmental vascular mechanisms that direct BP toward the higher percentiles of the Gaussian distribution curve.