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Very Promising (very + promising)
Terms modified by Very Promising Selected AbstractsAutomatic Creation of Object Hierarchies for Radiosity ClusteringCOMPUTER GRAPHICS FORUM, Issue 4 2000Gordon Müller Using object clusters for hierarchical radiosity greatly improves the efficiency and thus usability of radiosity computations. By eliminating the quadratic starting phase very large scenes containing about 100k polygons can be handled efficiently. Although the main algorithm extends rather easily to using object clusters, the creation of ,good' object hierarchies is a difficult task both in terms of construction time and in the way how surfaces or objects are grouped to clusters. The quality of an object hierarchy for clustering depends on its ability to accurately simulate the hierarchy of the energy flow in a given scene. Additionally it should support visibility computations by providing efficient ray acceleration techniques. In this paper we will present a new approach of building hierarchies of object clusters. Our hybrid structuring algorithm provides accuracy and speed by combining a highly optimized bounding volume hierarchy together with uniform spatial subdivisions for nodes with regular object densities. The algorithm works without user intervention and is well suited for a wide variety of scenes. First results of using these hierarchies in a radiosity clustering environment are very promising and will be presented here. The combination of very deep hierarchies (we use a binary tree) together with an efficient ray acceleration structure shifts the computational effort away from form factor and visibility calculation towards accurately propagating the energy through the hierarchy. We will show how an efficient single pass gathering can be used to minimize traversal costs. [source] Horizontal Roadway Curvature Computation Algorithm Using Vision TechnologyCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 2 2010Yichang (James) Tsai However, collecting such data is time-consuming, costly, and dangerous using traditional, manual surveying methods. It is especially difficult to perform such manual measurement when roadways have high traffic volumes. Thus, it would be valuable for transportation agencies if roadway curvature data could be computed from photographic images taken using low-cost digital cameras. This is the first article that develops an algorithm using emerging vision technology to acquire horizontal roadway curvature data from roadway images to perform roadway safety assessment. The proposed algorithm consists of four steps: (1) curve edges image processing, (2) mapping edge positions from an image domain to the real-world domain, (3) calibrating camera parameters, and (4) calculating the curve radius and center from curve points. The proposed algorithm was tested on roadways having various levels of curves and using different image sources to demonstrate its capability. The ground truth curvatures for two cases were also collected to evaluate the error of the proposed algorithm. The test results are very promising, and the computed curvatures are especially accurate for curves of small radii (less than 66 m/200 ft) with less than 1.0% relative errors with respect to the ground truth data. The proposed algorithm can be used as an alternative method that complements the traditional measurement methods used by state DOTs to collect roadway curvature data. [source] Conductive Organic Complex Salt TTF-TCNQ as a Mediator for Biosensors.ELECTROANALYSIS, Issue 24 2007An Overview Abstract Preparation and application of a conductive organic salt complex of tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) for analytical bioelectrochemistry as a mediator is overviewed in this work. The third-generation biosensors based on this charge transfer salt are very promising for biosensors applied in vivo. Such mediated biosensors have been studied mainly for glucose determination, but at present other substrates are being applied in this system more and more often. [source] Electrochemical Sensing of ExplosivesELECTROANALYSIS, Issue 4 2007Joseph Wang Abstract This article reviews recent advances in electrochemical sensing and detection of explosive substances. Escalating threats of terrorist activities and growing environmental concerns have generated major demands for innovative field-deployable tools for detecting explosives in a fast, sensitive, reliable and simple manner. Field detection of explosive substances requires that a powerful analytical performance be coupled to miniaturized low-cost instrumentation. Electrochemical devices offer attractive opportunities for addressing the growing explosive sensing needs. The advantages of electrochemical systems include high sensitivity and selectivity, speed, a wide linear range, compatibility with modern microfabrication techniques, minimal space and power requirements, and low-cost instrumentation. The inherent electroactivity of nitroaromatic, nitramine and nitroester compounds makes them ideal candidates for electrochemical detection. Recent activity in various laboratories has led to the development of disposable sensor strips, novel electrode materials, submersible remote sensors, and electrochemical detectors for microchip (,Lab-on-Chip') devices for on-site electrochemical detection of explosive substances. The attractive behavior of these electrochemical monitoring systems makes them very promising for addressing major security and environmental problems. [source] Amalgam Electrodes for ElectroanalysisELECTROANALYSIS, Issue 8 2003Øyvind Mikkelsen Abstract Liquid mercury is a unique material for the indicator electrode in voltammetry. One reason for this is the high overvoltage for hydrogen formation, thus extending the actual potential window. Diluted amalgams are important reaction products in voltammetric (polarographic) processes, however liquid amalgams are rarely used directly as electrode material for analytical purposes. Because of the fact that voltammetry is very suitable for field and remote monitoring, issues concerning the use of mercury electrodes in environmental analyses have led to considerable research effort aimed at finding alternative tools with acceptable performance. Solid electrodes are such alternatives. Different types of electrodes are reviewed. In particular, solid amalgam electrodes are very promising, with acceptable low toxicity to be used for field measurements. Solid amalgam electrodes are easy and cheap to construct and are stable over a reasonable time up to several weeks. Assessment of the toxicity risk and the long time stability for remote and unattended monitoring is discussed. The differences between solid dental amalgam electrodes, made by using techniques known from dental clinical practice, and mercury film or mercury layer electrodes on solid substrates are reviewed. In particular the dental technique for constructing solid amalgam electrodes gives advantage because it's fast and inexpensive. Also the technique for making dental amalgam has been explored and optimized over years by dentists, giving advantage when the same technique is used for constructing electrodes. Dental amalgam electrodes has been found to act similar to a silver electrodes, but with high overvoltage towards hydrogen. This make it possible to use the dental amalgam electrode for detection of zinc, cobalt and nickel in additions to other metals like lead, copper, thallium, cadmium, bismuth, iron etc. Also the use for reducible organic compounds is expected to be promising. [source] Nonparametric harmonic regression for estuarine water quality dataENVIRONMETRICS, Issue 6 2010Melanie A. Autin Abstract Periodicity is omnipresent in environmental time series data. For modeling estuarine water quality variables, harmonic regression analysis has long been the standard for dealing with periodicity. Generalized additive models (GAMs) allow more flexibility in the response function. They permit parametric, semiparametric, and nonparametric regression functions of the predictor variables. We compare harmonic regression, GAMs with cubic regression splines, and GAMs with cyclic regression splines in simulations and using water quality data collected from the National Estuarine Reasearch Reserve System (NERRS). While the classical harmonic regression model works well for clean, near-sinusoidal data, the GAMs are competitive and are very promising for more complex data. The generalized additive models are also more adaptive and require less-intervention. Copyright © 2009 John Wiley & Sons, Ltd. [source] Analysis of Genetically Complex EpilepsiesEPILEPSIA, Issue 2005Ruth Ottman Summary:, During the last decade, great progress has been made in the discovery of genes that influence risk for epilepsy. However, these gene discoveries have been in epilepsies with Mendelian modes of inheritance, which comprise only a tiny fraction of all epilepsy. Most people with epilepsy have no affected relatives, suggesting that the great majority of all epilepsies are genetically complex: multiple genes contribute to their etiology, none of which has a major effect on disease risk. Gene discovery in the genetically complex epilepsies is a formidable task. It is unclear which epilepsy phenotypes are most advantageous to study, and chromosomal localization and mutation detection are much more difficult than in Mendelian epilepsies. Association studies are very promising for the identification of complex epilepsy genes, but we are still in the earliest stages of their application in the epilepsies. Future studies should employ very large sample sizes to ensure adequate statistical power, clinical phenotyping methods of the highest quality, designs and analytic techniques that control for population stratification, and state-of-the-art molecular methods. Collaborative studies are essential to achieve these goals. [source] Sensors for the Detection and Quantification of Bacterial Contamination in Water for Human Use,ADVANCED ENGINEERING MATERIALS, Issue 5 2010Raquel Barbosa Queirós The deterioration of water quality by Cyanobacteria cause outbreaks and epidemics associated with harmful diseases in Humans and animals because of the toxins that they release. Microcystin-LR is one of the hepatotoxins most widely studied and the World Health Organization, recommend a maximum value of 1,µg,L,1 in drinking water. Highly specific recognition molecules, such as molecular imprinted polymers are developed to quantify microcystins in waters for human use and shown to be of great potential in the analysis of these kinds of samples. The obtained results were auspicious, the detection limit found, 1.5,µg,L,1, being of the same order of magnitude as the guideline limit recommended by the WHO. This technology is very promising because the sensors are stable and specific, and the technology is inexpensive and allows for rapid on-site monitoring. [source] Development of Biomimetic Chitosan-Based Hydrogels Using an Elastin-Like Polymer,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2010Joaquim S. Barbosa Chitosan and an elastin-like polymer, containing a specific osteoconductive sequence in the primary structure, have been combined to obtain bioactive injectable systems with enhanced mechanical properties and hydrogels. Obtained results indicate that the combination of such polymers may be very promising in the development of biomaterials for minimal invasive orthopaedic reconstructive applications or in bone tissue engineering. The figure shows a thermo-sensitive hydrogel, with a gelation point under physiological temperature. [source] Salmonella vaccines for use in humans: present and future perspectivesFEMS MICROBIOLOGY REVIEWS, Issue 4 2002Helen S Garmory Abstract In recent years there has been significant progress in the development of attenuated Salmonella enterica serovar Typhi strains as candidate typhoid fever vaccines. In clinical trials these vaccines have been shown to be well tolerated and immunogenic. For example, the attenuated S. enterica var. Typhi strains CVD 908- htrA (aroC aroD htrA), Ty800 (phoPphoQ) and ,4073 (cya crp cdt) are all promising candidate typhoid vaccines. In addition, clinical trials have demonstrated that S. enterica var. Typhi vaccines expressing heterologous antigens, such as the tetanus toxin fragment C, can induce immunity to the expressed antigens in human volunteers. In many cases, the problems associated with expression of antigens in Salmonella have been successfully addressed and the future of Salmonella vaccine development is very promising. [source] Using the TPS method for determining the thermal properties of concrete and wood at elevated temperatureFIRE AND MATERIALS, Issue 5 2006Bijan Adl-Zarrabi Abstract The transient plane source (TPS) method is shown to be very promising for determining thermal properties of materials at room temperature as well as temperatures up to 700°C. To investigate the applicability of the method it has been used in the study for determining thermal properties of wood (spruce) and concrete. Conductivity (,) and diffusivity (,) were determined simultaneously. The thermal properties thus obtained have been compared with some values found in literature. The paper also presents results where calculations using properties obtained with the TPS method are compared with fire test measurements. The results are very encouraging. Copyright © 2005 John Wiley & Sons, Ltd. [source] Inversion of time-dependent nuclear well-logging data using neural networksGEOPHYSICAL PROSPECTING, Issue 1 2008Laura Carmine ABSTRACT The purpose of this work was to investigate a new and fast inversion methodology for the prediction of subsurface formation properties such as porosity, salinity and oil saturation, using time-dependent nuclear well logging data. Although the ultimate aim is to apply the technique to real-field data, an initial investigation as described in this paper, was first required; this has been carried out using simulation results from the time-dependent radiation transport problem within a borehole. Simulated neutron and ,-ray fluxes at two sodium iodide (NaI) detectors, one near and one far from a pulsed neutron source emitting at ,14 MeV, were used for the investigation. A total of 67 energy groups from the BUGLE96 cross section library together with 567 property combinations were employed for the original flux response generation, achieved by solving numerically the time-dependent Boltzmann radiation transport equation in its even parity form. Material property combinations (scenarios) and their correspondent teaching outputs (flux response at detectors) are used to train the Artificial Neural Networks (ANNs) and test data is used to assess the accuracy of the ANNs. The trained networks are then used to produce a surrogate model of the expensive, in terms of computational time and resources, forward model with which a simple inversion method is applied to calculate material properties from the time evolution of flux responses at the two detectors. The inversion technique uses a fast surrogate model comprising 8026 artificial neural networks, which consist of an input layer with three input units (neurons) for porosity, salinity and oil saturation; and two hidden layers and one output neuron representing the scalar photon or neutron flux prediction at the detector. This is the first time this technique has been applied to invert pulsed neutron logging tool information and the results produced are very promising. The next step in the procedure is to apply the methodology to real data. [source] Fluorene-Based Oligomers for Highly Efficient and Stable Organic Blue-Light-Emitting DiodesADVANCED MATERIALS, Issue 23 2009Chang-Gua Zhen Highly efficient and stable blue-light-emitting materials consisting of oligofluorenyl blocks and charge transporting segments are synthesized. The external quantum efficiencies of the solution-processed light-emitting diodes were of up to 6.1% and 8.6% for undoped and doped devices, respectively. The exceedingly high efficiency and excellent stability of these devices suggest that these new developed materials are very promising for deep-blue-light OLEDs. [source] A numerical method for the study of shear band propagation in soft rocksINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 13 2009Marta Castelli Abstract This paper investigates the possibility of interpreting progressive shear failure in hard soils and soft rocks as the result of shear propagation of a pre-existing natural defect. This is done through the application of the principles of fracture mechanics, a slip-weakening model (SWM) being used to simulate the non-linear zone at the tips of the discontinuity. A numerical implementation of the SWM in a computation method based on the boundary element technique of the displacement discontinuity method (DDM) is presented. The crack and the non-linear zone at the advancing tip are represented through a set of elements, where the displacement discontinuity (DD) in the tangential direction is determined on the basis of a friction law. A residual friction angle is assumed on the crack elements. Shear resistance decreases on elements in the non-linear zone from a peak value at the tip, which is characteristic of intact material, to the residual value. The simulation of a uniaxial compressive test in plane strain conditions is carried out to exemplify the numerical methodology. The results emphasize the role played by the critical DD on the mechanical behaviour of the specimen. A validation of the model is shown through the back analysis of some experimental observations. The results of this back analysis show that a non-linear fracture mechanics approach seems very promising to simulate experimental results, in particular with regards to the shear band evolution pattern. Copyright © 2009 John Wiley & Sons, Ltd. [source] Forced vibrations in the medium frequency range solved by a partition of unity method with local informationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 9 2005E. De Bel Abstract A new approach for the computation of the forced vibrations up to the medium frequency range is formulated for thin plates. It is based on the partition of unity method (PUM), first proposed by Babu,ka, and used here to solve the elastodynamic problem. The paper focuses on the introduction of local information in the basis of the PUM coming from previous approximations, in order to enhance the accuracy of the solution. The method may be iterative and generates a PUM approximation leading to smaller models compared with the finite element ones required for a same accuracy level. It shows very promising results, in terms of frequency range, accuracy and computational time. Copyright © 2004 John Wiley & Sons, Ltd. [source] Linearized and non-linear acoustic/viscous splitting techniques for low Mach number flowsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 10 2003Mohammad Farshchi Abstract Computation of the acoustic disturbances generated by unsteady low-speed flow fields including vortices and shear layers is considered. The equations governing the generation and propagation of acoustic fluctuations are derived from a two-step acoustic/viscous splitting technique. An optimized high order dispersion,relation,preserving scheme is used for the solution of the acoustic field. The acoustic field generated by a corotating vortex pair is obtained using the above technique. The computed sound field is compared with the existing analytic solution. Results are in good agreement with the analytic solution except near the centre of the vortices where the acoustic pressure becomes singular. The governing equations for acoustic fluctuations are then linearized and solved for the same model problem. The difference between non-linear and linearized solutions falls below the numerical error of the simulation. However, a considerable saving in CPU time usage is achieved in solving the linearized equations. The results indicate that the linearized acoustic/viscous splitting technique for the simulation of acoustic fluctuations generation and propagation by low Mach number flow fields seems to be very promising for three-dimensional problems involving complex geometries. Copyright © 2003 John Wiley & Sons, Ltd. [source] Imprinted Conjugated Polymer Laser,ADVANCED MATERIALS, Issue 14 2003M. Gaal The realization of a distributed feedback structure by direct imprinting into a highly luminescent conjugated polymer and the subsequent lasing action from the structure (see cover) is reported. The fabrication is achieved using liquid imprinting; a new soft-lithographic technique, which is a combination of two established techniques: micromolding in capillaries and liquid embossing. The inexpensiveness and repeatability of the process makes this approach very promising for mass production of conjugated polymer solid-state laser devices. [source] Reliability and validity of the Junior Temperament and Character InventoryINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 4 2001Klaus Schmeck Abstract The Junior Temperament and Character Inventory (JTCI) was developed to assess the temperament (,novelty seeking', ,harm avoidance', ,reward dependence', ,persistence') and character (,self-directedness', ,cooperativeness', ,self-transcendence') dimensions of Cloninger's biosocial model of personality in children and adolescents. The psychometric properties of the JTCI are presented. We used the German version of JTCI in a clinical sample of 188 adolescent psychiatric patients (aged 12 to 18 years) and in a non-referred sample of 706 German adolescents of the same age range. Aspects of reliability and validity are discussed. We subjected the JTCI to confirmatory factor analysis and were able to replicate the temperament and character scales of the original TCI. The internal consistency of the scales was satisfactory with the exception of ,reward dependence' and ,persistence'. Construct validity was supported by good correspondence of JTCI dimensions with related constructs. Psychometric properties of the German version of JTCI are very promising. Results yield strong support for Cloninger's psychobiological theory. Copyright © 2001 Whurr Publishers Ltd. [source] Biological Indicator Systems in Floodplains , a ReviewINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 4 2006Frank Dziock Abstract Based on a literature review, the different approaches to biological indicator systems in floodplains are summarised. Four general categories of bioindication are defined and proposed here: 1. Classification indicators, 2.1 Environmental indicators, 2.2 Biodiversity indicators, 3. Valuation indicators. Furthermore, existing approaches in floodplains are classified according to the four categories. Relevant and widely used approaches in floodplains are explained in more detail. The results of the RIVA project are put into the context of these indication approaches. It is concluded that especially functional assessment approaches using biological traits of the species can be seen as very promising and deserve more attention by conservation biologists and floodplain ecologists. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Novel bioactive scaffolds with fibronectin recognition nanosites based on molecular imprinting technologyJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Elisabetta Rosellini Abstract Biomimetic materials for application in the field of tissue engineering are usually obtained through covalent bonding between the polymer backbone and the bioactive molecules. A totally new approach, proposed for the first time by our research group, for the creation of advanced synthetic support structures for cell adhesion and proliferation is represented by molecular imprinting (MI) technology. In this article, we describe the synthesis and characterization of molecularly imprinted polymers with recognition properties toward a fibronectin peptide sequence and their application as functionalization structures. Polymers, in the form of densely fused microgel particles, were obtained by precipitation polymerization. The imprinted particles showed good performance in terms of recognition capacity and quantitative rebinding; moreover, the epitope effect was observed, with the particles able to recognize and rebind not only the specific peptide sequence but also a larger fibronectin fragment. The cytotoxicity tests showed normal vitality in C2C12 myoblasts cultured in a medium that was put in contact with the imprinted particles. Therefore, imprinted particles were used to functionalize synthetic polymeric films by deposition on their surface. The deposition of the imprinted particles did not alter their specific recognition and rebinding behavior. The most remarkable result was obtained by the biological characterization: in fact, the functionalized materials appeared able to promote cell adhesion and proliferation. These results are very promising and suggest that MI can be used as an innovative functionalization technique to prepare bioactive scaffolds with an effective capacity for improving tissue regeneration. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Calorie restriction mimetics: an emerging research fieldAGING CELL, Issue 2 2006Donald K. Ingram Summary When considering all possible aging interventions evaluated to date, it is clear that calorie restriction (CR) remains the most robust. Studies in numerous species have demonstrated that reduction of calories 30,50% below ad libitum levels of a nutritious diet can increase lifespan, reduce the incidence and delay the onset of age-related diseases, improve stress resistance, and decelerate functional decline. A current major focus of this research area is whether this nutritional intervention is relevant to human aging. Evidence emerging from studies in rhesus monkeys suggests that their response to CR parallels that observed in rodents. To assess CR effects in humans, clinical trials have been initiated. However, even if results from these studies could eventually substantiate CR as an effective pro-longevity strategy for humans, the utility of this intervention would be hampered because of the degree and length of restriction required. As an alternative strategy, new research has focused on the development of ,CR mimetics'. The objective of this strategy is to identify compounds that mimic CR effects by targeting metabolic and stress response pathways affected by CR, but without actually restricting caloric intake. For example, drugs that inhibit glycolysis (2-deoxyglucose), enhance insulin action (metformin), or affect stress signaling pathways (resveratrol), are being assessed as CR mimetics (CRM). Promising results have emerged from initial studies regarding physiological responses which resemble those observed in CR (e.g. reduced body temperature and plasma insulin) as well as protection against neurotoxicity (e.g. enhanced dopamine action and up-regulated neurotrophic factors). Ultimately, lifespan analyses in addition to expanded toxicity studies must be accomplished to fully assess the potential of any CRM. Nonetheless, this strategy clearly offers a very promising and expanding research endeavor. [source] A superstructure-based optimal synthesis of PSA cycles for post-combustion CO2 capture,AICHE JOURNAL, Issue 7 2010Anshul Agarwal Abstract Recent developments have shown pressure/vacuum swing adsorption (PSA/VSA) to be a promising option to effectively capture CO2 from flue gas streams. In most commercial PSA cycles, the weakly adsorbed component in the mixture is the desired product, and enriching the strongly adsorbed CO2 is not a concern. On the other hand, it is necessary to concentrate CO2 to high purity to reduce CO2 sequestration costs and minimize safety and environmental risks. Thus, it is necessary to develop PSA processes specifically targeted to obtain pure strongly adsorbed component. A multitude of PSA/VSA cycles have been developed in the literature for CO2 capture from feedstocks low in CO2 concentration. However, no systematic methodology has been suggested to develop, evaluate, and optimize PSA cycles for high purity CO2 capture. This study presents a systematic optimization-based formulation to synthesize novel PSA cycles for a given application. In particular, a novel PSA superstructure is presented to design optimal PSA cycle configurations and evaluate CO2 capture strategies. The superstructure is rich enough to predict a number of different PSA operating steps. The bed connections in the superstructure are governed by time-dependent control variables, which can be varied to realize most PSA operating steps. An optimal sequence of operating steps is achieved through the formulation of an optimal control problem with the partial differential and algebraic equations of the PSA system and the cyclic steady state condition. Large-scale optimization capabilities have enabled us to adopt a complete discretization methodology to solve the optimal control problem as a large-scale nonlinear program, using the nonlinear optimization solver IPOPT. The superstructure approach is demonstrated for case studies related to post-combustion CO2 capture. In particular, optimal PSA cycles were synthesized, which maximize CO2 recovery for a given purity, and minimize overall power consumption. The results show the potential of the superstructure to predict PSA cycles with up to 98% purity and recovery of CO2. Moreover, for recovery of around 85% and purity of over 90%, these cycles can recover CO2 from atmospheric flue gas with a low power consumption of 465 k Wh tonne,1 CO2. The approach presented is, therefore, very promising and quite useful for evaluating the suitability of different adsorbents, feedstocks, and operating strategies for PSA, and assessing its usefulness for CO2 capture. Published 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Optimization of sigma amplitude threshold in sleep spindle detectionJOURNAL OF SLEEP RESEARCH, Issue 4 2000E. Huupponen Sleep spindles are transient EEG waveforms of non-rapid eye movement sleep. There is considerable intersubject variability in spindle amplitudes. The problem in automatic spindle detection has been that, despite this fact, a fixed amplitude threshold has been used. Selection of the spindle detection threshold value is critical with respect to the sensitivity of spindle detection. In this study a method was developed to estimate the optimal recording-specific threshold value for each all-night recording without any visual scorings. The performance of the proposed method was validated using four test recordings each having a very different number of visually scored spindles. The optimal threshold values for the test recordings could be estimated well. The presented method seems very promising in providing information about sleep spindle amplitudes of individual all-night recordings. [source] Nerve conduits and growth factor delivery in peripheral nerve repairJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2007Lukas A. Pfister Abstract Peripheral nerves possess the capacity of self-regeneration after traumatic injury. Transected peripheral nerves can be bridged by direct surgical coaptation of the two nerve stumps or by interposing autografts or biological (veins) or synthetic nerve conduits (NC). NC are tubular structures that guide the regenerating axons to the distal nerve stump. Early synthetic NC have primarily been made of silicone because of the relative flexibility and biocompatibility of this material and because medical-grade silicone tubes were readily available in various dimensions. Nowadays, NC are preferably made of biodegradable materials such as collagen, aliphatic polyesters, or polyurethanes. Although NC assist in guiding regenerating nerves, satisfactory functional restoration of severed nerves may further require exogenous growth factors. Therefore, authors have proposed NC with integrated delivery systems for growth factors or growth factor,producing cells. This article reviews the most important designs of NC with integrated delivery systems for localized release of growth factors. The various systems discussed comprise NC with growth factors being released from various types of matrices, from transplanted cells (Schwann cells or mesenchymal stem cells), or through genetic modification of cells naturally present at the site of injured tissue. Acellular delivery systems for growth factors include the NC wall itself, biodegradable microspheres seeded onto the internal surface of the NC wall, or matrices that are filled into the lumen of the NC and immobilize the growth factors through physical-chemical interactions or specific ligand-receptor interactions. A very promising and elegant system appears to be longitudinally aligned fibers inserted in the lumen of a NC that deliver the growth factors and provide additional guidance for Schwann cells and axons. This review also attempts to appreciate the most promising approaches and emphasize the importance of growth factor delivery kinetics. [source] Limonoids as cancer chemopreventive agentsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2006Sohail Ejaz Abstract Nutritional research on the health benefits of substances in plant foods has recently advanced to a new stage. The research frontier has moved from study of classical vitamin deficiency diseases to study of the thousands of phytochemicals that may have important physiological effects. Recent research suggests that citrus fruit consumers may be getting another health benefit from orange juice and other citrus products called limonoids, which appear to possess substantial anticancer activity. Limonoids are highly oxidized triterpenes present in Rutaceae and Maliaceae families. Several citrus limonoids have recently been subjected to anticancer screening utilizing laboratory animals and human breast cancer cells. The experimental results described that citrus limonoids may provide substantial anticancer actions. The compounds have been shown to be free of toxic effects in animal models, so potential exists for the use of limonoids against human cancer in either natural fruits, in citrus fortified with limonoids, or in purified forms of specific limonoids. Although the initial studies are very promising they have been conducted primarily with in vitro cell culture and animal models. Thus, research is needed to determine whether the limonoids may be useful in preventing or treating cancer in humans. Copyright © 2005 Society of Chemical Industry [source] Molluscan muscle systems in development and evolution,JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 3 2000G. Haszprunar The evolutionary history of the various molluscan muscle systems reflects drastic modifications and reductions as well as true innovations. No less than eight main and independent muscle systems of the Mollusca are described and, based on the current understanding of molluscan phylogeny, their evolutionary histories are outlined.New data on the myogenesis of the Polyplacophora by means of fluorescence-staining and image analysis by confocal laser scanning microscopy show that the pre-oral region recapitulates a ,worm-grid', and that the dorso-ventral musculature passes a stage of multiple seriality as found in adult Solenogastres. Old and new data on bivalves and recent studies on primitive gastropods provide clear evidence that the larval musculature of both groups (and thus possibly of all conchiferans) is entirely independent from the adult condition. The growth of shell-inserted muscles always necessitates substantial renewal of myocytes which is still poorly understood. Although very promising for phylogenetic purposes, the understanding of the developmental genetics of the various molluscan muscle systems is still in its infancy. [source] Unsuitable distinction between viable and dead Staphylococcus aureus and Staphylococcus epidermidis by ethidium bromide monoazideLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2009H. Kobayashi Abstract Aims:, The DNA-intercalating dye ethidium bromide monoazide (EMA) has recently been used as a DNA binding agent to differentiate viable and dead bacterial cells by selectively penetrating through the damaged membrane of dead cells and blocking the DNA amplification during the polymerase chain reaction (PCR). We optimized and tested the assay in vitro using Staphylococcus aureus and Staphylococcus epidermidis cultures to distinguish viable from dead bacteria, with the goal of reducing false positive PCR results. Methods and Results:, Viable and heat-inactivated bacteria were treated with EMA or left untreated before DNA extraction. A real-time PCR assay for the detection of the tuf gene in each DNA extract was used. Our results indicated that EMA influenced viable bacteria as well as dead bacteria, and the effect of EMA depended on the EMA concentration and bacterial number. Conclusions:, EMA is not a suitable indicator of bacterial viability, at least with respect to Staphylococcus species. Significance and Impact of the Study:, Determining the viability of pathogens has a major impact on interpreting the results of molecular tests for bacteria and subsequent clinical management of patients. To this end, several methods are being evaluated. One of these methods , intercalating DNA of dead bacteria by EMA , looked very promising, but our study found it unsatisfactory for S. aureus and coagulase-negative Staphylococci. [source] A 60-GHz CMOS receiver front-end with integrated 180° out-of-phase Wilkinson power dividerMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2010Jen-How Lee Abstract A 60-GHz receiver front-end with an integrated 180° out-of-phase Wilkinson power divider using standard 0.13 ,m CMOS technology is reported. The receiver front-end comprises a wideband low-noise amplifier (LNA) with 12.4-dB gain, a current-reused bleeding mixer, a baseband amplifier, and a 180° out-of-phase Wilkinson power divider. The receiver front-end consumed 50.2 mW and achieved input return loss at RF port better than ,10 dB for frequencies from 52.3 to 62.3 GHz. At IF of 20 MHz, the receiver front-end achieved maximum conversion gain of 18.7 dB at RF of 56 GHz. The corresponding 3-dB bandwidth (,3 dB) of RF is 9.8 GHz (50.8,60.6 GHz). The measured minimum noise figure (NF) was 9 dB at 58 GHz, an excellent result for a 60-GHz-band CMOS receiver front-end. In addition, the measured input 1-dB compression point (P1 dB) and input third-order inter-modulation point (IIP3) are ,20.8 dBm and ,12 dBm, respectively, at 60 GHz. These results demonstrate the adopted receiver front-end architecture is very promising for high-performance 60-GHz-band RFIC applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2688,2694, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25559 [source] Uniplanar coupled-fed printed PIFA for WWAN operation in the laptop computerMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2009Kin-Lu Wong Abstract In this article, a uniplanar printed PIFA (planar inverted-F antenna) with a coupling feed for application as an internal laptop computer antenna for penta-band WWAN (wireless wide area network) operation is presented. The proposed PIFA has a compact structure and can be easily printed on one side of a small 0.8-mm thick FR4 substrate of size 11 × 59 mm2, making it very promising to be embedded inside the casing of the laptop computer, especially for the thin-profile laptop computer. With the coplanar coupling feed, the large inductive input reactance of the PIFA at around 900 MHz is compensated, and dual-resonance excitation for the antenna's lower band at about 900 MHz is obtained, which allows it to easily cover GSM850/900 operation. A wide operating band is also achieved for the antenna's upper band at about 1900 MHz, and a bandwidth of larger than 500 MHz is obtained to cover GSM1800/1900/UMTS operation. That is, the proposed PIFA covers all the five operating bands of GSM850/900/1800/1900/UMTS for WWAN operation. Details of the proposed PIFA are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 549,554, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24084 [source] An analysis of substrate effects on transmission-lines for millimeter-wave CMOS RFIC applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2008Jin-Fa Chang Abstract A set of transmission lines (TLs) for millimeter-wave (MMW) CMOS RFIC applications was implemented in a standard 0.18 ,m CMOS technology and then postprocessed by CMOS-compatible inductively-coupled plasma (ICP) etching, which removed the silicon underneath the TLs completely. TL parameters such as characteristic impedance ZC, attenuation constant ,, phase constant ,, effective permittivity ,eff, minimum noise figure (NFmin), parallel capacitance/conductance C/G, and series inductance/resistance L/R, as a function of frequency were extracted. It was found that ,, ,eff, NFmin, C, and G were greatly improved after silicon removal. The state-of-the-art performances of the on-chip TLs-on-air suggest that they are very suitable for application to realize ultralow-noise MMW CMOS RFICs. Besides, the CMOS-compatible backside ICP etching technique is very promising for MMW system-on-a-chip applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 319,324, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23055 [source] | |||||||||||||||||||||||||||||||