bluuebunny/crossref_metadata_2025 huggingface dataset:
Neural Networks as Inference and Learning Engines
Authors: Crespo José L. , Mora Eduardo
Published: November 2008

Abstract: This paper presents an abridgment of a neural network constructive methodology and applications with real data. The neural network can be considered as the learning core and inference engine of an expert system that produces either different network designs or simulations as output, its input being data sequences. Basically, it consists of additive structural learning, limiting it by a cross‐validation technique.

Considerations about uncertainty treatment in neural networks are also presented, including uncertainty in data, in neuron activation, in outputs, and combination of several uncertainty sources.

Applications include three different sets of data, all of them related to the energy field. First, river streamflow estimation is discussed. Then CO2 concentration prediction from gas injection rate is studied. Finally, the program learns to imitate a feedwater control system in a nuclear reactor. All tests show good results, as can be seen when compared with other standard methods.
Efficient Modeling Scheme for Transient Analysis of Inelastic RC Structures
Authors: Kunnath Sashi K. , Reinhom Andrei M.
Published: November 2008

Abstract: Simple modeling schemes for efficient and reliable analysis of reinforced concrete structures in the inelastic range are presented. The objective of the modeling techniques is to represent overall behavior in terms of macromodels. A reinforced concrete structure is discretized into a series of macroelements: beam columns, shear walls, and general‐purpose inelastic springs. Each element macro‐model is developed from distributed flexibility concepts in which the effects of spread plasticity are implicitly included. Nonlinear material behavior is specified by means of hysteretic force‐deformation models that incorporate stiffness degradation, strength deterioration, and pinching or bondslip effects. The models are incorporated into a microcomputer program that is capable of analyzing two‐dimensional or entire three‐dimensional wall‐frame systems that can be discretized into a series of interconnected parallel frames. Solution modules for nonlinear static, monotonic, quasistatic cyclic, and transient seismic loads are developed. The efficiency and reliability of the modeling are demonstrated in terms of its effectiveness in reproducing experimentally observed behavior.
A Hypertext Decision Support Model for Contractor Prequalification
Authors: AbouRizk Simaan M. , Chehayeb Nader N.
Published: November 2008

Abstract: Owners of construction projects often make decisions regarding prequalification of contractors for a specific project. This paper describes a hypertext approach to enhance the contractor prequalification process. Relevant recent research is discussed, and potential benefits of using multiattribute decision making and hypertext information systems versus expert systems are explored. The developed prototype system uses the same criteria as QUALIFIER‐1 and allows the user to make a rational decision about assigning importance weights to various prequalification factors. The flexibility of the system in altering various weights for factors according to the project being considered is discussed. A database system and a procedural language linked to the hypertext system are added to automatically store relevant information about contractors for future reference and to calculate user's input, respectively.
An Open Architecture for Environmental Decision Support
Authors: Frysinger Steven P.
Published: November 2008

Abstract: A class of environmental information systems, called environmental decision support systems, is defined. The requirements for such systems are elaborated, and a software architecture that supports these requirements is developed. This architecture is then illustrated through the example of the Sandia Environmental Decision Support System (SEDSS). The SEDSS is a family of workstation applications based on the architecture developed by AT&T Bell Laboratories and prototyped in collaboration with the Environmental Restoration Organization of Sandia National Laboratories. Sharing a common user interface philosophy and software architecture, the members of the SEDSS family are designed to facilitate human decision making with respect to the hydrologic aspects of hazardous waste management. In order to achieve these objectives, the SEDSS family integrates geographic information systems, hydrologic models, Monte Carlo simulation, and a highly interactive graphical user interface, into a coherent software system based on the X Window System.

This architecture is currently being applied to such similar environmental management problems as well‐head protection area analysis, in addition to nongroundwater problems such as coastal fisheries management. Applied research in environmental decision support systems continues in the areas of uncertainty management, treatment of qualitative parameters, and the human factors of environmental decision making.
Neural Networks for Evaluating CPT Calibration Chamber Test Data
Authors: Goh Anthony T. C.
Published: November 2008

Abstract: The feasibility of using neural network models for evaluating CPT calibration chamber test data is investigated. The backpropagation neural network algorithm was used to analyze the data. After learning from a set of randomly selected patterns, the neural network model was able to produce reasonably accurate predictions for patterns not included in the training set. The neural network performance was found to be simpler and more effective than regression analysis for modeling the CPT test data. Correlations between the cone measurements and the engineering properties of sand can be developed using the generalization capabilities of the neural network.
A Plan‐Based Framework for Design: Implementation
Authors: Ndumu D. T. , Izzuddin B. A. , Smith D. Lloyd
Published: November 2008

Abstract: The development of automated design assistants requires a generic framework in which design knowledge can be directly represented and utilized. The framework should be transparent, allowing a user to view and query the system's reasoning and to control its solution processes. Current knowledge‐based systems techniques have failed to provide such a framework because their inference procedures do not directly support design transformations. This paper describes the design and implementation of a generic framework for design based on planning. Issues addressed include the representation and use of strategic control knowledge, object‐level design knowledge, normative knowledge, and general knowledge within a planning framework. Examples of the functioning of the framework in the design of beams to satisfy lateral torsional buckling requirements are presented. The efficiency and limitations of the implementation are discussed and possible extensions to the system described.
Multicriteria Structural Optimization as a Technique for Quality Improvement in the Design Process
Authors: Eschenauer H. A.
Published: November 2008

Abstract: After being able to determine the structural behavior by means of finite methods (e.g., finite elements, finite differences, boundary elements), an important goal of engineering activities is to improve and to optimize technical designs, structural assemblies, and components. The task of vector or multicriteria structural optimization is to support the engineer in finding the best‐possible design alternatives of specific structures. The “best‐possible” or “optimal” structure is the one that corresponds to the designer's desired concept, meeting at the same time all kinds of multidisciplinary requirements referring to manufacturing, erecting, operating, etc. In comparison with the trialand‐error method generally used in the engineering environment and based on an intuitive heuristic approach, the determination of optimal solutions by means of correctly applied optimization procedures is more reliable and efficient. These procedures will be a need in the design process in future, and they are already increasingly entering industrial practice. Two examples of real‐life structures are introduced in this paper.
Motion Planning for an Autonomous Compactor in a Waste Landfill Site
Authors: Kunigahalli Raghavan , Russell Jeffrey S. , Tserng Hui‐Ping
Published: November 2008

Abstract: This paper describes the algorithms and detailed path‐planning methodologies developed to enable autonomous spreading and compaction processes in a waste landfilling operation. A given landfill site is spatially decomposed into cells using a recursive spatial decomposition technique. The cell size is determined using a probabilistic model for waste generation. Variation in the amount of waste generated on a given day is handled by a further spatial decomposition of a cell into monominoes. The recursive spatial decomposition processes of a landfill site into cells and each cell into monominoes are accomplished by employing a variant of quadtree data structure. A three‐dimensional path plan for an autonomous compactor that considers a variable working gradient in the range of 3:1 to 2:1 is generated for a pair of monominoes. Automatic location of the working place for a compactor is accomplished by a recursive traversal of the quadtree structure. The algorithms have been implemented using a computer‐graphic functional interface standard with C‐program binding.
Robotics in Civil Engineering
Authors: Haas Carl , Skibniewski Miroslaw , Budny Eugeniusz
Published: November 2008

Abstract: Robots have been investigated for automation of construction, maintenance, and inspection of civil works since the early 1980s. This paper describes the progress of robotics in civil engineering from the early 1980s to the mid‐1990s. It focuses on the environment and motivation for implementation of robotics, identifies key centers of development, identifies regional differences, and describes progress in key areas. It also traces the emergence and change of development strategies over time, it identifies practical achievements, and it identifies key developments for the future. It concludes that despite many false starts and setbacks, significant progress has been made, and significant changes are on the horizon.
Minimum Weight Design of Large Structures on a Network of Workstations
Authors: Kumar S. , Adeli H.
Published: November 2008

Abstract: Advances in performance of local area networks and microprocessors are providing significant computational capability at a relatively low cost. This paper is concerned with development of a distributed algorithm for minimum weight design of large structures on a network of workstations using biologically inspired genetic algorithms. Communication constructs from the software library Parallel Virtual Machine (PVM) have been used for message passing between the workstations. The algorithm has been applied to minimum weight design of two example structures. Performance estimates are provided based on the granularity and parallelization efficiency of the distributed model. The speedup of the distributed algorithm increases with the size of the structure, making it particularly suitable for optimization of large structures. For large structures, a high average speedup of about 10 is achieved using 11 workstations. The high scalability of the distributed genetic algorithm demonstrates that a cluster of workstations provides a cost‐effective alternative for high‐performance computing for coarse‐grained applications such as the GA‐based structural optimization.
A Pavement Condition‐Rating Model Using Backpropagation Neural Networks
Authors: Eldin Neil N. , Senouci Ahmed B.
Published: November 2008

Abstract: This paper presents an overview of the neural‐network technique as a management tool for maintenance of flexible pavement. The paper discusses the development and implementation of a neural network for the condition rating of roadway sections. The condition‐rating scheme developed by Oregon State Department of Transportation was used as the basis for the development of the network presented. A training set of 744 cases was used to train the network, and a set of 1736 cases was used to test the generalization ability of the system. The network adequately learned the training examples with an average training error of 0.019 and was able to determine the correct condition ratings with an average testing error of 0.023. The network's ability to deal with noisy data also was tested. Up to 60% noise was added to the data and introduced to the network. The results showed that the network presented could identify condition rating relationships at high levels of‐noise. Finally, an expert determination was compared with that produced by the network. The network was able to mimic the expert's condition ratings with an average error of 0.0354.
Nonlinear Transient Dynamic Analysis on Parallel Processors
Authors: Rao A. Rama Mohan , Loganathan K. , Raman N. V.
Published: November 2008

Abstract: Two approaches for parallel implementation of nonlinear transient dynamic analysis algorithms have been presented in this paper. One is based on geometric decomposition, and the other one is processor‐farm approach. Both shared memory (Magnum IV) and transputer‐based message‐passing systems have been chosen for implementation of the proposed parallel algorithms for dynamic analysis. Multithread concepts have been employed on transputer networks to optimize the code by overlapping communications with computations. Numerical studies indicate that explicit transient dynamic analysis can be implemented effectively employing geometric decomposition technique both on shared and message‐passing systems.
Use of Adaptive Networks in Fuzzy Control of Civil Structures
Authors: Faravelli Lucia , Yao Timothy
Published: November 2008

Abstract: The guidelines for implementing a fuzzy active control strategy for civil engineering structures are discussed. The paper focuses attention on the gap between a successful numerical example and the technical design of the device. Several subjective steps are identified in the design process, and an optimization of the design is attempted using an adaptive network.
Distributed Sensing and Control Technology for Intelligent Civil Infrastructure Systems
Authors: Bullock Darcy , Schwehm Chris , Broemmelsiek John
Published: November 2008

Abstract: Sensing and control functions are the fundamental technologies on which many civil infrastructure control and monitoring systems are constructed. Early civil infrastructure control and monitoring systems employed a centralized computing model for sensor processing and actuator control. These systems required extensive wiring to route power, sensor, and control signals among the distributed input and output devices. Furthermore, the operation of the entire system depended on one or two computers. Abstractly, these civil infrastructure applications are a realtime data acquisition and control system. Due to the dramatic decrease in computing costs, it is now feasible to construct these real‐time systems using dozens or even hundreds of distributed processors linked with a data communication network. This allows the controllers to be located adjacent to sensors and actuators, thereby reducing the need for long lengths of multiconductor wire that is subject to noise and breakage. Also, failure of a single processor does not necessarily cause the entire system to fail. This paper introduces the reader to a technology called LonWorks for constructing distributed sensing and control systems. The LonWorks technology is essentially a data communication network that links together extremely small computers called Neurons. Particular emphasis is placed on describing the communication architecture and emphasizing how the distributed Neuron communication processors are designed to ensure a truly modular and open architecture.
Integration of a Model for Hydraulic Analysis of Water Distribution Networks with an Evolution Program for Pressure Regulation
Authors: Savić Dragan A. , Walters Godfrey A.
Published: November 2008

Abstract: This paper describes a computational model for hydraulic analysis of water distribution networks specifically developed to be used with an evolution program (EP) for optimal pressure regulation. The hydraulic solver uses a method based on loop equations, namely, the linear theory method (LTM). Network topology analysis is performed using depth‐first‐search and breadth‐first‐search algorithms that are devised to ensure the connectedness of a network and to enable easy identification of loops. The model developed enables rapid evaluation of a network for different topologic conditions (i.e., the connectivity of the nodes caused by different valve settings) as required by the EP. A variable number of LTM iterations throughout the evolution process is used to speed up the search. A sample network problem is used to illustrate the efficiency of both the model for hydraulic analysis and the EP.
Uncertainty Modeling of Earthquake Hazards
Authors: Sánchez‐Silva M. , Blockley D. I. , Taylor C. A.
Published: November 2008

Abstract: The evaluation of the expected response of existing projects (i.e., buildings, lifelines, facilities, cities, regions, etc.) during an earthquake is difficult and complex. The interstory drift of a building and the response of the main structural system are examples of parameters typically used to make judgments. The behavior of a project clearly depends on structure, but it also depends on many other factors that often are not considered. These include safety culture, management, condition, use, construction, materials, and so on. The modeling and measurement of these factors vary in quality because they are very different in nature. A model is proposed that enables these factors to be put together to assess the proneness to failure of a particular project. Uncertainty is classified into fuzziness, incompleteness, and randomness. Hierarchically arranged holons describe the essential form of the project and capture inherent fuzziness. The model includes tests (such as audits) that a project must pass in order to be declared dependably safe. It is argued that the ingenuity of these tests is the best defense against incompleteness. Engineering and scientific models are included as appropriate. An interval probability is used to measure the available evidence about the dependability that a holon will be able to sustain its function during an earthquake.
A Fuzzy Diagnostic Model for Diagnosing Cracks in Reinforced Concrete Structures
Authors: Chao Ching‐Ju , Cheng Fu‐Ping
Published: November 2008

Abstract: A fuzzy diagnostic model based on the concept of cause‐and‐effect diagraming and fuzzy set theory is presented. Two levels of parameters representing the causes of cracks in concrete are used to form fuzzy sets. The parameters represent materials used, fabrication of structural elements, loading, and environmental conditions. An expert system that links the parameters by means of fuzzy set theory is constructed using finite universal sets consisting of membership functions and fuzzy vectors. The model is capable of interpreting the causes of crack formation by means of a cause‐and‐effect diagram. Two examples are presented to demonstrate the effectiveness of the model in diagnosing crack formation in reinforced concrete structures.
Generic Representation of Solid‐Object Geometry for Genetic Search
Authors: Bentley Peter J. , Wakefield Jonathan P.
Published: November 2008

Abstract: This paper examines the first stage of using genetic algorithms in design—how to encode designs as chromosomes. Generic representations capable of describing the geometry of any solid object to eliminate the unnecessary duplication of work at this stage are explored. A suitable low‐parameter, spatial‐partitioning representation is then proposed, using partitions consisting of six‐sided polyhedra intersected by planes. Finally, the coding of the representation is examined, with the conclusion that allelic coding with control genes and user‐definable, fixed‐value alleles would provide the most flexible system.
A Growth Model for Form Generation Using a Hierarchical Evolutionary Approach
Authors: Rosenman M. A.
Published: November 2008

Abstract: This paper presents an evolutionary approach to design using a hierarchical decomposition/aggregation growth model. It argues that the evolutionary approach fits well to the well‐known generate‐and‐test approach in design and is especially suited to design situations where the (inter)relationships between complex arrangements of elements and their behavior are not known. The evolutionary approach is used as the computational method for the synthesis and evaluation stage of the design process. A hierarchical model of design is used to avoid the combinatorial problems involved in linear models. The concepts are exemplified in the context of the design of house plans.
Using the Genetic Design Methodology for Structure Configuration
Authors: Roston Gerald P. , Sturges Robert H.
Published: November 2008

Abstract: Human designers and optimization codes are very good at improving the performance of existing designs; however, due to time and resource constraints, human designers tend to limit the range of alternative configurations considered. This paper presents a methodology, called genetic design (GD), to aid the designer by generating viable design alternatives. GD uses formal grammars for artifact description and representation, evaluates the artifacts automatically, and manipulates the representations with genetic programming—like operations. GD can explore a wide breadth of the available design space, though at shallow depth, and presents alternatives to the human designer. The combination of GD's ability to explore the design space and the human engineer's ability to optimize existing configurations promotes the production of viable new design concepts by avoiding the inefficiencies associated with trial‐and‐error methods. This paper explores one application of GD: the design of simple truss bridges.
Modeling Design Exploration as Co‐Evolution
Authors: Maher Mary Lou , Poon Josiah
Published: November 2008

Abstract: Most computer‐based design tools assume that designers work with a well‐defined problem. However, this assumption has been challenged by current research. The explorative aspect of design, especially during conceptual design, is not fully addressed. This paper introduces a model for problem‐design exploration and how this model can be implemented using the genetic algorithm (GA) paradigm. The basic GA, which does not support our exploration model, evaluates individuals from a population of design solutions with an unchanged fitness function. This approach to evaluation implements search with a prefixed goal. Modifications to the basic GA are required to support exploration. Two approaches to implement a co‐evolving GA are presented and discussed in this paper: one in which the fitness function is represented within the genotype, and a second in which the fitness function is modeled as a separately evolving population of genotypes.
An Exploration‐Based Evolutionary Model of a Generative Design Process
Authors: Gero John S. , Kazakov Vladimir A.
Published: November 2008

Abstract: An exploration‐based generative model of design is proposed. Shape grammars are used as a framework for the knowledge representation within this model. The routine design problem over the state space generated using a fixed shape grammar and the creative design problem over the extended state space generated by using an extended shape grammar—the family of shape grammars which includes the original one—are formulated. Two evolutionary algorithms that produce superior designs and shape grammars are presented. In the first method, exploration and search processes occur simultaneously whereas in the second they are explicitly separated.
Motion Control of Adaptive Truss Structures Using Fuzzy Rules
Authors: Tsou Poyo , Shen M. H. Herman
Published: November 2008

Abstract: This note describes a design of the fuzzy control system for the kinematic maneuvers of an adaptive system consisting of a truss‐type structure with several variable‐length members. The deformations of the adaptive modules are coordinatively governed by fuzzy controllers according to the distance signals between the endpoint of the structure and the moving target. In addition, an adaptive gain tuning technique is investigated in this study. The advantages of applying adaptive gain tuning on motion control of adaptive truss structures are presented. The simulation results show that the application to this model is effective and can be easily implemented in the microcomputer.
Neural Network–Spreadsheet Integration for Earth‐Moving Operations
Authors: Kartam Nabil
Published: November 2008

Abstract: This paper examines the potential to combine trained artificial neural networks with application development software to expand their applicability to construction management problems. The problem of determining optimal equipment combinations for the dozer/scraper earth‐moving team, under various physical conditions of the haul road, was chosen for its limited scope and lack of effective solution methods currently available. An introduction to the problem provides the current state of technology for handling this problem. The problem is analyzed to determine the information and resource requirements as well as the input and output forms that would be desirable for such a program. The paper proceeds through the design process and development of the program schematic. Programming of the system is examined, including the development process used to train the neural network, conversion of the network to a spreadsheet form, and spreadsheet manipulation of the network outputs. The paper concludes with recommendations for expansion of the program for more complex haul road conditions and equipment types.
Intelligent Geometric Modeling of Standard Bridges
Authors: Lakmazaheri Sivand
Published: November 2008

Abstract: Artificial intelligence (AI) is a branch of computer science that deals with the development of approaches and techniques for enabling the machine to mimic human intelligence. The marriage of AI and computer‐aided design (CAD) results in a new breed of systems called intelligent CAD systems. These systems are superior to conventional CAD systems in that they exhibit certain capabilities, such as deductive reasoning, that have been attributes to intelligent beings.

Deductive reasoning is a central activity in CAD in general and in geometric modeling in particular. This paper presents a framework for developing intelligent CAD systems that support deductive reasoning. More specifically, the paper (1) discusses the integration of predicate logic as a mechanism for deductive reasoning with conventional CAD systems and (2) illustrates the use of the framework for geometric modeling of standard bridges. This illustration involves (1) representing the geometry of standard bridges using the language of predicate logic and (2) generating, modifying, and verifying the geometry of standard bridges via logical inference.
An Approach to Preliminary Design of Precast Pretensioned Concrete Bridge Girders
Authors: Lounis Z. , Cohn M. Z.
Published: November 2008

Abstract: This paper presents an approach to the preliminary design of simple span precast pretensioned highway bridge girders using mathematical optimization methods. This type of bridge system is competitive for short and medium spans but also can accommodate long‐span bridges if girder splicing and continuity are introduced. The bridge design problem is formulated as a nonlinear programming problem and is solved by the projected lagrangian algorithm. Several design objectives are investigated either separately or simultaneously with the aim of achieving cost‐efficient bridge designs. The approach is used to generate a new set of five optimal girder sections and then to determine the girder spacing and span length capability of each precast girder. The five sections types (A, B, C, D, and E) proposed herein are more cost‐effective than the corresponding Canadian standard sections because for similar depths they achieve greater span length and girder spacing while requiring less concrete and prestressing steel. This study also enables identification of the governing design requirements (serviceability and/or ultimate limit states active constraints) that may be adopted as optimality criteria when simplified preliminary designs of this bridge type for different design codes and girder sections are required.
Application of Pattern Recognition to Damage Localization
Authors: Stubbs Norris , Garcia Gabe
Published: November 2008

Abstract: Pattern recognition is used as a basis to localize damage in structures. Feature vectors that depend on the predamaged and postdamaged mode shapes are developed. Classification criteria are developed to classify elements in the feature space into damaged and undamaged classes. The formulation is applied to a three‐dimensional finite element model of a bridge girder. The accuracy of the localization results is then evaluated.
Optimal Sensor Placement for Mode Shapes Via Shannon's Sampling Theorem
Authors: Stubbs Norris , Park Sooyong
Published: November 2008

Abstract: The feasibility of using Shannon's sampling theorem to reconstruct exact mode shapes of a structural system from a limited number of sampling points is investigated. Shannon's sampling theorem for the time domain is reviewed. The theorem is then extended to the spatial domain. Mode shapes are reconstructed from a limited amount of data, and the reconstructed mode shapes are compared with the exact mode shapes. On the basis of the results, simple rules are proposed for the placement of accelerometers in modal parameter extraction experiments. The feasibility of applying the rules and the extended Shannon's theorem to damage localization in a simple structure is demonstrated.
Association between Presenilin‐1 and TRAF6 modulates regulated intramembrane proteolysis of the p75NTR neurotrophin receptor
Authors: Powell James C. , Twomey Ciara , Jain Raunak , McCarthy Justin V.
Published: November 2008

The p75 neurotrophin receptor (p75NTR) is a member of the tumour necrosis factor superfamily, which relies on the recruitment of cytosolic protein partners including the tumour necrosis factor receptor‐associated factor 6 (TRAF6) E3 ubiquitin ligase to produce cellular responses. Recently, p75NTR was also shown to undergo presenilin‐dependent, γ‐secretase‐mediated regulated intramembrane proteolysis. In this study, we report the characterization of a highly conserved TRAF6‐binding site (PxExxAr/Ac) in presenilin‐1 (PS1) that mediates nerve growth factor (NGF)‐induced association between PS1 and TRAF6. We demonstrate that disruption of this interaction between PS1 and TRAF6 inhibits TRAF6 autoubiquitination and γ‐secretase cleavage of p75NTR. Additionally, we show that PS1‐deficiency antagonizes NGF‐induced I‐κB degradation. Finally, we also show that p75NTR is a substrate for TRAF6‐mediated ubiquitination and that TRAF6 E3 ligase activity is required for regulated intramembrane proteolysis of p75NTR. In summary, our data suggest that an NGF‐induced association between PS1 and TRAF6 influences regulated intramembrane proteolysis of p75NTR.
Altered hippocampal long‐term synaptic plasticity in mice deficient in the PGE2 EP2 receptor
Authors: Yang Hongwei , Zhang Jian , Breyer Richard M. , Chen Chu
Published: November 2008

Our laboratory demonstrated previously that PGE2‐induced modulation of hippocampal synaptic transmission is via a pre‐synaptic PGE2 EP2 receptor. However, little is known about whether the EP2 receptor is involved in hippocampal long‐term synaptic plasticity and cognitive function. Here we show that long‐term potentiation at the hippocampal perforant path synapses was impaired in mice deficient in the EP2 (KO), while membrane excitability and passive properties in granule neurons were normal. Importantly, escape latency in the water maze in EP2 KO was longer than that in age‐matched EP2 wild‐type littermates (WT). We also observed that long‐term potentiation was potentiated in EP2 WT animals that received lipopolysaccharide (LPS, i.p.), but not in EP2 KO. Bath application of PGE2 or butaprost, an EP2 receptor agonist, increased synaptic transmission and decreased paired‐pulses ratio in EP2 WT mice, but failed to induce the changes in EP2 KO mice. Meanwhile, synaptic transmission was elevated by application of forskolin, an adenylyl cyclase activator, both in EP2 KO and WT animals. In addition, the PGE2‐enhanced synaptic transmission was significantly attenuated by application of PKA, IP3 or MAPK inhibitors in EP2 WT animals. Our results show that hippocampal long‐term synaptic plasticity is impaired in mice deficient in the EP2, suggesting that PGE2‐EP2 signaling is important for hippocampal long‐term synaptic plasticity and cognitive function.
Enhanced generation of Alzheimer’s amyloid‐β following chronic exposure to phorbol ester correlates with differential effects on alpha and epsilon isozymes of protein kinase C
Authors: Da Cruz e Silva Odete A. B. , Rebelo Sandra , Vieira Sandra I. , Gandy Sam , Da Cruz e Silva Edgar F. , Greengard Paul
Published: November 2008

Alzheimer’s amyloid precursor protein (APP) sorting and processing are modulated through signal transduction mechanisms regulated by protein phosphorylation. Notably, protein kinase C (PKC) appears to be an important component in signaling pathways that control APP metabolism. PKCs exist in at least 11 conventional and unconventional isoforms, and PKCα and PKCε isoforms have been specifically implicated in controlling the generation of soluble APP and amyloid‐β (Aβ) fragments of APP, although identification of the PKC substrate phospho‐state‐sensitive effector proteins remains challenging. In the current study, we present evidence that chronic application of phorbol esters to cultured cells in serum‐free medium is associated with several phenomena, namely: (i) PKCα down‐regulation; (ii) PKCε up‐regulation; (iii) accumulation of APP and/or APP carboxyl‐terminal fragments in the trans Golgi network; (iv) disappearance of fluorescence from cytoplasmic vesicles bearing a green fluorescent protein tagged form of APP; (v) insensitivity of soluble APP release following acute additional phorbol application; and (vi) elevated cellular APP mRNA levels and holoprotein, and secreted Aβ. These data indicate that, unlike acute phorbol ester application, which is accompanied by lowered Aβ generation, chronic phorbol ester treatment causes differential regulation of PKC isozymes and increased Aβ generation. These data have implications for the design of amyloid‐lowering strategies based on modulating PKC activity.
The glutamatergic nature of TRPV1‐expressing neurons in the spinal dorsal horn
Authors: Zhou Hong‐Yi , Chen Shao‐Rui , Chen Hong , Pan Hui‐Lin
Published: November 2008

The transient receptor potential vanilloid receptor 1 (TRPV1) is expressed on primary afferent terminals and spinal dorsal horn neurons. However, the neurochemical phenotypes and functions of TRPV1‐expressing post‐synaptic neurons in the spinal cord are not clear. In this study, we tested the hypothesis that TRPV1‐expressing dorsal horn neurons are glutamatergic. Immunocytochemical labeling revealed that TRPV1 and vesicular glutamate transporter‐2 were colocalized in dorsal horn neurons and their terminals in the rat spinal cord. Resiniferatoxin (RTX) treatment or dorsal rhizotomy ablated TRPV1‐expressing primary afferents but did not affect TRPV1‐ and vesicular glutamate transporter‐2‐expressing dorsal horn neurons. Capsaicin significantly increased the frequency of glutamatergic spontaneous excitatory post‐synaptic currents and miniature excitatory post‐synaptic currents in almost all the lamina II neurons tested in control rats. In RTX‐treated or dorsal rhizotomized rats, capsaicin still increased the frequency of spontaneous excitatory post‐synaptic currents and miniature excitatory post‐synaptic currents in the majority of neurons examined, and this effect was abolished by a TRPV1 blocker or by non‐NMDA receptor antagonist. In RTX‐treated or in dorsal rhizotomized rats, capsaicin also produced an inward current in a subpopulation of lamina II neurons. However, capsaicin had no effect on GABAergic and glycinergic spontaneous inhibitory post‐synaptic currents of lamina II neurons in RTX‐treated or dorsal rhizotomized rats. Collectively, our study provides new histological and functional evidence that TRPV1‐expressing dorsal horn neurons in the spinal cord are glutamatergic and that they mediate excitatory synaptic transmission. This finding is important to our understanding of the circuitry and phenotypes of intrinsic dorsal horn neurons in the spinal cord.
New trends in face rejuvenation by hyaluronic acid injections
Authors: Andre Pierre
Published: November 2008

Background  Injection techniques are growing, thanks to safer and more suitable filling agents. Hyaluronic acid (HA), a biodegradable product, has become the “gold standard” for fillers. With its wide range, it not only improves wrinkles but also restores volume.

Methods  Since 1996, many patients have been injected for wrinkles, fine lines, and nasolabial folds. For 3 years, more viscous HAs have been launched, allowing us to restore volumes. Some new procedures are described. These can correct anomalies of the chin and of the nose, and allow a betterment of the periocular area by correcting hollow and falling eyebrows.

Results  The use of different HAs for each area and indication is suitable and offers real possibilities to rejuvenate the skin without downtime. Longevity of the correction depends on treated areas, HA used, and on the individual.

Conclusion  HAs are safe and suitable for wrinkles and volume restoration, but besides their mechanical properties, they have numerous physiological functions. With the analysis of literature about the action mechanism of HA and its receptors, it is evident that HA also has a stimulating action on different physiological process.
Clinical tolerance and efficacy of capryloyl salicylic acid peel compared to a glycolic acid peel in subjects with fine lines/wrinkles and hyperpigmented skin
Authors: Oresajo Christian , Yatskayer Margarita , Hansenne Isabelle
Published: November 2008

Background  Several chemical agents are currently used to perform superficial peels of the face to reduce facial hyperpigmentation and fine lines/wrinkles. Some of the most commonly used agents are alpha hydroxyl acids, such as glycolic acid (GA), or beta hydroxy acid, such as salicylic acid.

Aim  This study aims to compare the efficacy of GA to that of a novel derivative of salicylic acid, capryloyl salicylic acid (LHA).

Subjects/Methods  In a split‐face study, 50 female volunteers between the ages of 35 and 60 years with mild to moderate facial hyperpigmentation and fine lines/wrinkles were randomized and LHA or GA peel was applied to one side of the face. Increasing peel concentrations were applied (5–10% LHA or 20–50% GA) based on the tolerance level of the subjects and clinical observations of an expert dermatologist for 12 weeks at biweekly intervals.

Results  Of the 44 volunteers who completed the study, at 12 weeks 41% of LHA‐treated and 30% of GA‐treated subjects demonstrated significant reduction of fine lines/wrinkles compared to baseline. Forty‐six percent of LHA‐treated subjects and 34% of GA‐treated subjects showed significant reduction of hyperpigmentation compared to baseline. LHA treatment was better than GA peels, although there were no statistically significant differences between the two groups.

Conclusions  Five percent to 10% of LHA peel is generally safe and as effective as 20–50% GA peel in reducing facial hyperpigmentation and fine lines/wrinkles.
A study to determine the efficacy of a novel handheld light‐emitting diode device in the treatment of photoaged skin
Authors: Sadick Neil S
Published: November 2008

The use of visible or near‐infrared spectral light alone for the purpose of skin rejuvenation has been previously reported in the literature. These devices use large arrays of diodes to deliver light to the skin. In this study, a novel method of light‐emitting diode (LED) photo rejuvenation incorporating a combination of these wavelengths delivered from a small handheld unit is proposed. Twenty‐two subjects with facial rhytides received eight light therapy treatments over a course of 4 weeks, using the Omnilux handheld LED system. Assessment of global skin grading was evaluated at weeks 6, 9, and 12 by a dermatologist. Additional outcome measures included assessments of clinical photography and patient satisfaction scores. Seventy‐four percent of the subjects reported a visible improvement in fine lines and wrinkles at 8 weeks posttreatment. Combination red and near‐infrared LED therapy delivered from a small portable handheld unit represents an effective and acceptable method of photo rejuvenation. Further studies to optimize the parameters of treatment are required.
Evaluation of additive effects of hydrolyzed jojoba (Simmondsia chinensis) esters and glycerol: a preliminary study
Authors: Meyer Jaimi , Marshall Brooke , Gacula Maximo , Rheins Lawrence
Published: November 2008

Background  Glycerol has long served the topical prescriptive and personal care industry as a versatile and functional active and inactive ingredient. In skin care products, it acts primarily as an emollient, softening the skin through robust humectant hydration action. Hydrolyzed Jojoba Esters K‐20W (K‐20W) have been shown to increase skin hydration and improve sensory skin “feel” when included in a variety of skin, hair, and nail care cosmetic/personal care formulations. The addition of glycerol and hydrolyzed jojoba esters provides a substantial long‐acting 24 h (moisturizing) skin hydration effect for topical products.

Aim  A small pilot study was conducted to support the “proof of concept” that an enhanced, additive role exists between these two ingredients resulting in a long‐term (24 h) skin moisturization effect.

Method  Topical treatments were applied to the skin (lower leg) of subjects, and evaluations were made at baseline and 8‐ to 24‐h postapplication. Skin hydration data were obtained via bioinstrumental transepidermal water loss (TEWL) measurements and expert clinical skin grading, including standardized digital clinical photography.

Results  Clinical skin grading evaluations and TEWL measurements found that significantly lower evaporative (P < 0.05) TEWL values occurred in the topical formulations containing 3.75% glycerol and 1.25% K‐20W (hydrolyzed jojoba esters) than with glycerol alone in a standard base skin care lotion at 8 and 24 h posttreatment.

Conclusion  This preliminary data “proof of concept” supports the position that glycerol and hydrolyzed jojoba esters work in tandem to enhance skin moisturization for at least 24 h. This unique moisturizing potential may prove valuable in the future development of cosmetic and over‐the‐counter/prescriptive topical products, including new medicaments containing botanicals. This fact is further reinforced with the recent greater commercial use and demand for defined safe botanicals in cosmetic as well as pharmaceutical topical formulations. Additional mechanistic studies are underway.
Natural Arctium lappa fruit extract improves the clinical signs of aging skin
Authors: Knott Anja , Reuschlein Katja , Mielke Heiko , Wensorra Ursula , Mummert Christopher , Koop Urte , Kausch Martina , Kolbe Ludger , Peters Nils , Stäb Franz , Wenck Horst , Gallinat Stefan
Published: November 2008

Background  Subclinical, chronic tissue inflammation involving the generation of cytokines (e.g., interleukin‐6 and tumor necrosis factor‐alpha) might contribute to the cutaneous aging process.

Aims  This study aims to screen for an active ingredient with anti‐inflammatory (i.e., reduction of interleukin‐6 and tumor necrosis factor‐alpha) and matrix‐stimulating efficacy which improves the clinical signs of skin aging in vivo.

Patients/methods  In vitro studies with pure Arctiin were performed investigating the inhibition of cytokine induction and stimulation of collagen neosynthesis. In vivo home‐in‐use studies using an Arctium lappa fruit extract–containing formulation were carried out to determine procollagen and hyaluronan synthesis, hyaluronan synthase‐2 gene expression, and reduction of wrinkle volume after treatment.

Results  In vitro studies on human dermal fibroblasts and monocyte‐derived dendritic cells supplemented with pure Arctiin showed relative to untreated control cells a stimulation of collagen synthesis and a decrease in interleukin‐6 and tumor necrosis factor‐alpha concentration, respectively. In addition, topical in vivo application of an A. lappa fruit extract–containing formulation for 12 weeks significantly stimulated procollagen synthesis and increased hyaluronan synthase‐2 expression as well as hyaluronan levels compared to vehicle‐treated control areas. Similarly, after a 4‐week treatment with an A. lappa fruit extract–containing formulation, wrinkle volume in the crow's feet area was significantly reduced as compared to treatment with the vehicle.

Conclusions  Our data show that topical treatment with a natural A. lappa fruit extract significantly improves the metabolism of the dermal extracellular matrix and leads to a visible wrinkle reduction in vivo. In conclusion, A. lappa fruit extract represents a targeted means to regenerate dermal structures and, thus, offers an effective treatment option for mature skin.
Cosmetic surgery for congenital nail deformities
Authors: Richert B , Choffray A , De La Brassinne M
Published: November 2008

Only a few nail dystrophies may be improved by surgery: malalignment of the big toenail, racquet thumbs, trapezoidal nails, and vertical implantation of the nail on the fifth toe. Knowledge of the surgical management of these deformities may allow a nice cosmetic outcome if performed by skilled surgeons.
Effect of Styrene–Butadiene Rubber Latex on Mechanical Properties of Cementitious Materials Highlighted by Means of Nanoindentation
Authors: Wang R. , Lackner R. , Wang P.‐M.
Published: November 2008

Abstract:  In this paper, micro‐mechanical properties of styrene–butadiene rubber (SBR) latex‐modified cement pastes identified by means of the nanoindentation (NI) technique are related to macro‐mechanical properties of SBR latex‐modified mortars obtained from standard test methods, considering an SBR latex/cement ratio varying from 0% to 20%. For this purpose, the average value of the hardness and the so‐called indentation modulus of the different material phases of the cement paste, i.e. calcium–silicate–hydrate (CSH), portlandite, anhydrous cement, etc., obtained from NI are compared with the compressive and flexural strengths, on the one hand, and the dynamic elastic modulus of SBR latex‐modified mortars, on the other hand. This comparison revealed a linear correlation between the dynamic elastic modulus and the indentation modulus and between the compressive strength, flexural strength and hardness. Thus, the obtained results clearly indicate the finer‐scale origin of the macroscopic elastic and strength properties, linking the mechanical properties at the so‐called mortar scale to the cement‐paste scale.