bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical Properties and Change in Microstructure in the Nitriding Process of Cu-Added Steels
Authors: Kawasaki Kaoru , Ujita Katsuya , Takahashi Jun , Sugiyama Masaaki , Kawakami Kazuto
Published: January 2010

From the point of view of nitriding treatment(570°C), Cu precipitation is also occurred in the steel containing 1.3mass%Cu at this temperature. In this study, the behavior of nitriding in ultra low carbon steels containing Cr and/or Al and/or V are investigated. The following results are obtained : (1)After nitriding treatment the distribution of vickers hardness(Hv) differs in added nitriding element. (2)Profile of hardness in thickness is resulted from mainly precipitation hardening of nitride. (3)The high fatigue limit of nitrided steel is occurred by residual stress in vicinity of the surface. (4) Nitride precipitation is promoted by Cu precipitation that occurs in early stage of heat treatment.
Revisiting Carbon Based Metallic Compounds – Nanoscale Surface Science and Environmental Catalysis
Authors: Okumura Hideyuki , Arai K. , Nishiyama Y. , Yamasue Eiji , Ishihara Keiichi N.
Published: January 2010

Catalytic ability on 12 kinds of carbide powders was investigated at room temperature using NOx gas degradation. They are largely classified into two groups, depending on whether the reaction involves a nitrogen gas in air or not. The carbon dangling bonds largely contribute to the reaction, while the accompanied metal atoms play an important role for adsorbing/dissociating nitrogen gas. Mechanical milling or annealing, as long as without agglomeration, is an effective method for activating powder catalysis, producing new surfaces with plenty catalytic sites. A new concept of catalysis is presented, based on the Schottky barrier-like model, where the charge imbalance is produced at the interface between the non-uniform thin oxide and the carbide.
Nanophase Hardfacing New Possibilities for Functional Surfaces
Authors: Reisgen Uwe , Balashov B. , Stein L. , Geffers C.
Published: January 2010

During the last years, materials science has focused more and more on the development of nanomaterials. Reasons for that are the enormous advantages these materials can offer for various applications as their special structure yields the improvement of the material properties, such as hardness, strength and ductility. However, the production of especially “massive” nanomaterials is quite complex. The present study demonstrates the possibility of producing iron- or chromium-based nanophase hardfaced coatings with a thickness of several millimetres by means of common arc welding methods (TIG, PTA). An appropriate alloy composition allows to control the structural properties of the solidifying weld metal. Specific variations of the alloying elements enable the realisation of a nanostructured solidification of the carbides and/or borides with cooling rates that are common for arc surfacing processes. In the hardfaced coatings phase dimensions of approximately 100-300 nm were achieved. Based on the results it is established that the influence of the surfacing parameters and of the coating thickness and thus the influence of the heat control on the nanostructuring process is, compared with the influence of the alloy composition, of secondary importance. Several tests showed that the generation of nanoscale structures in the hardfaced coatings allows the improvement of mechanical properties, wear resistance and corrosion resistance. Potential applications for these types of hardfaced coatings lie, in particular, in the field of cutting tools that are exposed to corrosion and wear.
Influence the Thermal Process of the Removing the Varnish Coats to the Cleanness of the Surface Aluminium Scrap
Authors: Litwińczyk-Kwaśnicka M. , Rozpondek M. , Siwka J.
Published: January 2010

The recycling of aluminium packagings is the complex process in due to of the variety of applied varnishes. The compounds of these varnishes in the raised temperature are decomposed and the reactions products may be: gas and/or carbon and in some cases mineral compounds from pigments and the filling materials. Removing the layer organic from aluminium packagings be holds mainly on the thermal processes. In the paper are described the results of removing the varnish coats from surface of the aluminium cans for drinks. The investigations were carried out in the rotary furnace (Linn High Therm) in the temperatures 620 oC in air atmosphere. The surface of sheet after thermal process was submitted the chemical microanalysis on the scanning microscopes Inspect F. It was found that it is possible to obtain practically no oxidizing surface of aluminum sheet. On the surface were the solid residues from mineral pigments and filling materials e.g. oxides Ti, Ba and Si.
Influence of Annealing on the Microstructure and Wear Performance of Diamond/NiCrAl Composite Coating Deposited through Cold Spraying
Authors: Li Chang Jiu , Suo Xin Kun , Yang Guan Jun , Li Cheng Xin
Published: January 2010

Diamond/NiCrAl composite powder with a diamond content of 40vol.% is prepared by mechanical alloying process with diamond powder and NiCrAl alloy powder. Cold spraying is employed to deposit diamond/NiCrAl composite coating. To enhance the bonding between diamond particles and NiCrAl matrix, annealing treatment is applied to the as-sprayed coating. The effect of annealing treatment conditions on the microstructure and microhardness and abrasive wear performance of the coating is investigated. The results show the microstructure of the composite powder is completely retained in the coating owing to the low temperature of spray powder during cold spray process. The interface between diamond and NiCrAl matrix is enhanced by the CrxCy layers formed during annealing treatment. Moreover, the cohesion of deposited particles in the coating is improved through metal element diffusion during heat treatment. The hardness and wear performance of the coating is related to coating microstructure and the bonding at the interfaces between diamond particles and NiCrAl matrix.
Internal Stress in EB-PVD Thermal Barrier Coating under Heat Cycle
Authors: Suzuki Kenji , Shobu Takahisa
Published: January 2010

As the top coating, zirconia with 4 mol% yttria was electron beam-physical vapor deposited (EB-PVD) on the bond coating of CoNiCrAlY. The substrates were rotated during EB-PVD process and the rotation speeds were 5 (R5) and 10 rpm (R10). The thickness of the top coating was 0.12 mm. In order to investigate the change of the internal stress in the top coating under a heat cycle, the specimen was heated from a room temperature to 1293K, the internal stress was measured in-situ by a strain scanning method with hard synchrotron X-rays at each temperature step. For the specimen R5, the internal stress increased from about -100 MPa to about 100 MPa with the increase in temperature, then the stress relaxation of the top coating occurred over 1093K. In the cooling process, the internal stress decreased, however, the changing rate of the internal stress was small as compared with the heating process. This was caused by the feather-like structure sintered. For the specimen R10, the internal stress did not show a tension in the heating process, it was caused by the separation between columnar structures.
Application of the Concept of Local Fatigue Strength after Shot Peening of Notched Components Based on Numerical Simulations
Authors: Klemenz Manuel , Schulze Volker
Published: January 2010

Shot Peening is a well established mechanical surface treatment to induce compressive residual stresses and work hardening into the surface layer of components exposed to cyclic loading. Due to the induced changes in the surface layer, the fatigue limit increases significantly. The concept of local fatigue strength is based on the comparison of the locally effective fatigue limit with locally active loads in order to estimate the maximum outer loading that will not exceed fatigue limit. In this paper an approach of using simulated surface characteristics after shot peening for the determination of the local fatigue strength will be presented. The complex stress distribution due to cyclic bending of notched geometries will also be determined by FEM. Finally the simulated estimation of the fatigue limit of differently notched specimens of AISI 4140 will be verified with experimentally determined fatigue limits.
In Situ Observations of the Densification Behavior of WC-FeAl-B Composites during Liquid Phase Sintering
Authors: Ahmadian M. , Reid M. , Dippenaar Rian , Chandra Tara , Wexler David , Calka Andrzej
Published: January 2010

The densification behavior of WC composites based on iron aluminide binder was investigated using laser scanning confocal mi¬croscopy (LSCM). Doped Fe60Al40 alloys with boron levels ranging from 0 to 0.1 wt% were used as the aluminide binders. The aluminide binders were prepared using controlled atmosphere ring grinding and then blended with WC powder. The composite powder compacted in an alumina crucible and held in a platinum holder in the confocal microscope. The temperature increased from ambient temperature up to 1500 °C under high purity argon. The presence of boron was found to facilitate compaction of the composites and improve the wetting between WC and FeAl binder during liquid phase sintering. Increasing the amount of boron in the binder resulted in the melting of binder at lower temperature and increasing of the compacting of the intermetallic tungsten carbide composites.
Properties of Small Rotary Engine Housing Fabricated by Aluminum Alloy Matrix Composites
Authors: Fuyama Nobuyuki , Terayama Akira , Fujii Toshio , Tani Hajime , Danjo Shinji , Sasaki Gen
Published: January 2010

To develop the small engine used for the wireless control helicopter, a very high power density source will be required. The rotary engine (RE) is advantageous in the points such as a volume of the engine, the exhaust gas emissions, and the vibrations. In this research, in order to develop the small RE, the design of the combustion chamber was reviewed. Additionally, the method of the surface treatment of the rotor housing was investigated by the friction wear test to enable the material substitution for aluminum matrix composites. The friction wear tests of composite materials, the Cr and Ni-plated material were conducted.
As a result, the sample with the most excellent abrasion resistance was the composite material reinforced with Al2O3 fibers. The wear-loss of this composite material was 1/10 compared with the Ni-plated material. This composite material formed oil pockets between the fiber and the matrix, and a friction coefficient fell below 0.1. Then, the aluminum rotor housing reinforced partially by Al2O3 fiber was fabricated using a low-pressure infiltration method. The maximum power of the small RE (1 rotor, 30 cc) which built in this housing reached about 5 PS in the range from 13,000 to 15,000 rpm. The inside of the housing used composite materials was not damaged even after 30 hours. On the other hand, the flaking off part was observed on the inside part in the case with the housing used the Ni-plated material. Additionally, the output and the torque of the RE made of composite materials were higher than those of the Ni-plated material. This was considered because the friction coefficient of composite materials was lower than that of the Ni-plated material. Finally, the small unmanned helicopter equipped with RE succeeded in a stable flight.
Effect of Alumina Fibers on Fabrication Process and Characteristics of Alumina Fiber Reinforced Aluminum Alloy Composites
Authors: Mizumoto Masayuki , Ohgai Takeshi , Kagawa Akio
Published: January 2010

In order to develop the alumina fiber reinforcements optimized to FRMMCs, the effect of characteristics of alumina fibers on the fabrication process and the characteristics of the alumina fiber reinforced Al alloy composites was investigated. Alumina fibers which have different alumina content were prepared. Alumina content in the fibers was varied from 80% to 100%. Al-4mass%Cu alloy, Al-12mass%Si alloy and Al-10masss%Mg alloy were used as matrix. The FRMMC specimens were fabricated by a low-pressure infiltration process (LPI process). The formability of the preform was improved with increasing alumina content in the fibers. However, broken fibers were observed in the preform when alumina fibers with high alumina content were used. The number of the broken fibers seemed to be increased with increasing alumina content in the fibers. This result could be attributable to a change of fiber strength resulting from a change of alumina content in the fiber. The FRMMC specimens were characterized by using Vickers hardness test. The Vickers hardness of FRMMC specimens depended on the elasticity or the hardness of the fibers. The results obtained suggest that the characteristics of the FRMMCs largely depend on the intrinsic characteristics of the reinforcement fibers.
High Strength Natural Fibers for Improved Polymer Matrix Composites
Authors: Monteiro Sérgio Neves , Satyanarayana Kestur Gundappa , Lopes Felipe Perissé Duarte
Published: January 2010

A statistical evaluation based on the Weibull method was performed to correlate the mechanical properties and the diameter of different lignocellulosic fibers. The sisal, rami and curaua fibers were found to have a hyperbolic correlation between their ultimate strength and diameter. This permitted to select thinner high strength fibers, with over 1000 MPa, as reinforcement for the strongest polymer composites ever fabricated with these fibers. A structural analysis was conducted by electron microscopy to identify the strengthening mechanism for both, the high performance fiber and their improved polymer composites.
Characterization of Metal Matrix Composites by Synchrotron Refraction Computed Topography
Authors: Müller Bernd R. , Lange Axel , Harwardt M. , Hentschel M.P.
Published: January 2010

X-ray computed tomography is an important tool for evaluating the three dimensional microstructure of modern materials non-destructively. To resolve material structures in the micrometre range and below high brilliance synchrotron radiation has to be taken. But materials of low absorption or mixed phases show a weak absorption contrast at there interfaces. A Contrast enhancement can be achieved by exploiting the refraction of X-rays at interfaces. This technique was developed and applied at the NDT department of the Federal Institute for Materials Research and Testing (BAM) during the last decade. It meets the actual demand for improved non-destructive characterisation of high performance composites, ceramics and other low density materials and components. The technique is based on Ultra Small Angle Scattering (USAXS) by micro structural elements causing phase related effects like refraction and total reflection at a few minutes of arc as the refractive index of X-rays is nearly unity. The extraordinary refraction contrast of inner surfaces is far beyond absorption effects and hence especially useful for materials of low absorption or mixed phases, showing similar X-ray absorption properties. Crack orientation and fibre-matrix debonding in plastics, polymers, ceramics and metal-matrix-composites after cyclic loading and hydro thermal aging can be visualized. By combining the refraction technique with the computed tomography technique the three dimensional imaging of the micro structure of the materials is obtained. In most cases the investigated inner surface and interface structures correlate to mechanical properties. Recent results with a sub-micrometer resolution will be presented.
Development of a Low Cost Process for Manufacturing of Ti-MMC by Roll-Diffusion-Bonding
Authors: Testani Claudio , Ferraro F.
Published: January 2010

Titanium-alloy matrix composites (TMC) are nowadays one of the material class with the highest specific resistance from room temperature up to 800° C. Centro Sviluppo Materiali SpA (CSM) efforts have been focused on the developing of an innovative solution to reduce the process costs. The new approach consists in an experimental “diffusion bonding” plant for co-rolling at high temperature sheets of titanium alloy and silicon carbide monofilaments fabrics. The result is a process cost reduction of about 40% respect to HIP process. The experimental pilot plant has been proposed for patent with n° 2006A000261 on may 2006. This paper describes the pilot plant and the process results. The metallographic examination on products shows full bonded samples (100 mm wide and 1500 mm long) obtained in a work field that is at least 100 times faster than that of HIP. High temperature tensile tests have been carried on Roll Diffusion Bonded specimens and the results are reported in comparison with those obtained by Isostatic Pressing (HIP) and Thermal- Spraying (TS) processes on the same composite.
High Temperature Characteristics of Unidirectionally Solidified Eutectic Ceramic Composites and some Potential Applications
Authors: Waku Yoshiharu , Yasuda Hideyuki
Published: January 2010

We have recently developed ceramic eutectics, which are named Melt Growth Composites (MGCs). The binary MGCs (Al2O3/YAG and Al2O3/GAP binary systems) have a novel microstructure, in which continuous networks of single-crystal Al2O3 phases and single-crystal oxide compounds (YAG or GAP) interpenetrate without grain boundaries. To characterize the entangled structure of the typical MGCs, the X-ray computerized tomography (micro X-ray CT) was performed at a synchrotron radiation facility Spring8. The micro X-ray CT showed that the Al2O3 and the GAP are entangled with each other. Therefore, the MGCs have excellent high-temperature strength characteristics, creep resistance, superior oxidation resistance and thermal stability in the air atmosphere at very high temperatures. To achieve higher thermal efficiency for gas turbine systems, MGC bowed stacking nozzle vanes have been fabricated on an experimental basis.
Costimulator B7-DC Attenuates Strong Th2 Responses Induced by Nippostrongylus brasiliensis
Authors: Ishiwata Kenji , Watanabe Naohiro , Guo Miao , Tomihara Kei , Brumlik Michael J. , Yagita Hideo , Pardoll Drew , Chen Lieping , Shin Tahiro
Published: January 2010

The caliber and magnitude of T cell responses are regulated by costimulatory molecules following the engagement of TCRs and MHC molecules. B7-DC has the highest homology with B7-H1 in the B7 family, and both of them bind an immunoregulatory molecule, programmed death 1. Previous studies have demonstrated that B7-DC stimulates T cell proliferation and CTL generation, which sharply contrasts the inhibitory role of B7-H1. Th2 cytokines prompt B7-DC expression, which in turn enhances Th1 responses. In this study, we used an intestinal nematode, Nippostrongylus brasiliensis, to induce strong Th2 responses and to evaluate B7-DC function under Th2-polarizing conditions in vivo. By either blocking B7-DC expression during N. brasiliensis infection or by examining N. brasiliensis-infected B7-DC knockout mice, we observed enhanced eosinophilia, the overproduction of serum IgE, and increased Th2 cytokine production along with decreased Th1 cytokine production (particularly IFN-γ production), indicating that B7-DC inhibits Th2 responses. Our results further demonstrate that the inhibition of Th2 responses by B7-DC occurs independently of programmed death 1 but conceivably acts through an as yet unknown alternative receptor that enhances Th1 responses. Although the deficiency of B7-DC expression that enhanced the production of IL-13 paradoxically resulted in better protection against N. brasiliensis infection, our results show that B7-DC plays an important role in bolstering a robust Th1 response that is required for effective antiviral and anticancer immunity, even under a strong Th2-polarizing environment induced by N. brasiliensis infection.
TCR Mimic Monoclonal Antibody Targets a Specific Peptide/HLA Class I Complex and Significantly Impedes Tumor Growth In Vivo Using Breast Cancer Models
Authors: Verma Bhavna , Neethling Francisca A. , Caseltine Shannon , Fabrizio Ginger , Largo Sherly , Duty J. Andrew , Tabaczewski Piotr , Weidanz Jon A.
Published: January 2010

Our laboratory has developed a process for generating mAbs with selectivity to unique peptides in the context of MHC molecules. Recently, we reported that RL4B, an mAb that we have called a TCR mimic (TCRm) because it recognizes peptide in the context of MHC, has cytotoxic activity in vitro and prevented growth of tumor cells in a prophylactic setting. When presented in the context of HLA-A2, RL4B TCRm recognizes the peptide GVLPALPQV derived from human chorionic gonadotropin (hCG)-β. In this study, we show that RL4B TCRm has strong binding affinity for the GVLPALPQV peptide/HLA-A2 epitope and fine binding specificity for cells that express endogenous hCGβ Ag and HLA-A2. In addition, suppression of tumor growth with RL4B TCRm was observed in orthotopic models for breast cancer. Using two aggressive human tumor cell lines, MDA-MB-231 and MCF-7, we provide evidence that RL4B TCRm significantly retards tumor growth, supporting a possible role for TCRm agents in therapeutic settings. Moreover, tumors in mice responded to RL4B TCRm therapy in a dose-dependent manner, eliminating tumors at the highest dose. RL4B TCRm strongly detects the hCGβ peptide/HLA-A2 epitope in human primary breast tumor tissue, but does not react or reacts weakly with normal breast tissue from the same patient. These results further illustrate the selective nature of TCRm Abs and the clinical relevance of the GVLPALPQV peptide/HLA-A2 epitope expression in tumor cells, because they provide the first evidence that Abs that mimic the TCR can be used to markedly reduce and suppress tumor growth.
NCX 4040, a Nitric Oxide-Donating Aspirin, Exerts Anti-Inflammatory Effects through Inhibition of IκB-α Degradation in Human Monocytes
Authors: Ricciotti Emanuela , Dovizio Melania , Di Francesco Luigia , Anzellotti Paola , Salvatore Tania , Di Francesco Andrea , Sciulli Maria G. , Pistritto Giuseppa , Monopoli Angela , Patrignani Paola
Published: January 2010

NO-donating aspirins consist of aspirin to which a NO-donating group is covalently linked via a spacer molecule. NCX 4040 and NCX 4016 are positional isomers with respect to the ‑CH2ONO2 group (para and meta, respectively) on the benzene ring of the spacer. Because positional isomerism is critical for antitumor properties of NO-donating aspirins, we aimed to compare their anti-inflammatory effects with those of aspirin in vitro. Thus, we assessed their impacts on cyclooxygenase-2 activity (by measuring PGE2 levels), protein expression, and cytokine generation(IL-1β, IL-18, TNF-α, and IL-10) in human whole blood and isolated human monocytes stimulated with LPS. Interestingly, we found that micromolar concentrations of NCX 4040, but not NCX 4016 or aspirin, affected cyclooxygenase-2 expression and cytokine generation. We compared the effects of NCX 4040 with those of NCX 4016 or aspirin on IκB-α stabilization and proteasome activity in the LPS-stimulated human monocytic cell line THP1. Differently from aspirin and NCX 4016, NCX 4040, at a micromolar concentration range, inhibited IκB-α degradation. In fact, NCX 4040 caused concentration-dependent accumulation of IκB-α and its phosphorylated form. This effect was not reversed by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, an inhibitor of guanylyl cyclase, thus excluding the contribution of NO-dependent cGMP generation. In contrast, IκB-α accumulation by NCX 4040 may involve an inhibitory effect on proteasome functions. Indeed, NCX 4040 inhibited 20S proteasome activity when incubated with intact cells but not in the presence of cell lysate supernatants, thus suggesting an indirect inhibitory effect. In conclusion, NCX 4040 is an inhibitor of IκB-α degradation and proteasome function, and it should be taken into consideration for the development of novel anti-inflammatory and chemopreventive agents.
An exploratory study of visual and psychological correlates of preference for onscreen subpixel‐rendered text
Authors: Bias Randolph G. , Larson Kevin , Huang Sheng‐Cheng , Aumer‐Ryan Paul R. , Montesclaros Chris
Published: January 2010

Font‐rendering technologies play a critical role in presenting clear and aesthetic fonts to enhance the experience of reading from computer screens. This article presents three studies investigating visual and psychological correlates of people's preferences toward different onscreen text enhancements such as ClearType developed by Microsoft. Findings suggested that (a) people's acuity and hue sensitivity were two major factors that affect their preferences to ClearType's color filtering of subpixels on fonts, and (b) specific personality traits such as disagreeableness also could correlate with people's impressions of different onscreen text enhancements that were used. These empirical data would inform digital typographers and human–computer interaction scientists who aim to develop better systems of onscreen reading.
Extreme precipitation over Southeastern Brazil in the austral summer and relations with the Southern Hemisphere annular mode
Authors: Vasconcellos Fernanda Cerqueira , Cavalcanti Iracema F. A.
Published: January 2010

Southeastern Brazil is a highly industrialized and populated region which largely contributes to the country's economy. Extreme precipitation over this region can cause floods and landslides occurrences or lack of precipitation that can affect many sectors of economy. The objective of this work is to identify atmospheric characteristics associated with austral summer extreme precipitation over part of Southeastern Brazil. The atmospheric characteristics obtained from wet and dry composites suggest that extreme precipitation was associated with anomalous circulation over the region, forced by a PSA‐like wavetrain intensified by the Southern Annular Mode. Copyright © 2010 Royal Meteorological Society
Hydrological ensemble prediction and verification for the Meuse and Scheldt basins
Authors: Van den Bergh Joris , Roulin Emmanuel
Published: January 2010

We present the hydrological ensemble prediction system developed at the Royal Meteorological Institute (RMI) of Belgium to study the Meuse and Scheldt basins. An overview is presented of the hydrological model and the operational setup of the forecasting system. We present some results of a 3‐year hindcast that was performed to verify the quality of the probabilistic forecasting system. The raw precipitation forecasts and streamflow forecasts are considered: we provide skill scores and relative economic value for various subcatchments of the Meuse and Scheldt basins. Copyright © 2010 Royal Meteorological Society
Highway alignment optimization through feasible gates
Authors: Kang Min Wook , Schonfeld Paul , Jong Jyh‐Cherng
Published: January 2010

An efficient optimization approach, called feasible gate (FG), is developed to enhance the computation efficiency and solution quality of the previously developed highway alignment optimization (HAO) model. This approach seeks to realistically represent various user preferences and environmentally sensitive areas and consider them along with geometric design constraints in the optimization process. This is done by avoiding the generation of infeasible solutions that violate various constraints and thus focusing the search on the feasible solutions. The proposed method is simple, but improves significantly the model's computation time and solution quality. Such improvements are demonstrated with two test examples from a real road project.
ITS applications for work zones
Authors: Golly Tyler , de Barros Alexandre G. , Falls Lynne Cowe
Published: January 2010

The use of Intelligent Transportation Systems (ITS) in construction work zones to disseminate traffic information has increased significantly in recent years, mainly with the use of Variable Message Signs (VMS). VMS are used based on the assumption that informed drivers will make better travel decisions, thereby reducing congestion. However, the extent of change in driver behavior is difficult to predict prior to ITS deployment. This difficulty leads to the larger problem of justifying investment in ITS. This article proposes an ITS deployment decision support tool using micro‐simulation. The approach determines the required diversion effectiveness of a work zone ITS deployment using VMS. The methodology was tested using the Glenmore Trail/Elbow Drive/5th Street interchange project (GE5) in Calgary, Canada. The results indicate that the proposed approach will assist agencies in justifying ITS investment by exhibiting the potential resultant societal benefits.
Modeling the evolutions of day‐to‐day route choice and year‐to‐year ATIS adoption with stochastic user equilibrium
Authors: Huang Hai‐Jun , Liu Tian‐Liang , Yang Hai
Published: January 2010

Suppose that in an urban transportation network there is a specific advanced traveler information system (ATIS) which acts for reducing the drivers' travel time uncertainty through provision of pre‐trip route information. Because of the imperfect information provided, some travelers are not in compliance with the ATIS advice although equipped with the device. We thus divide all travelers into three groups, one group unequipped with ATIS, another group equipped and in compliance with ATIS advice and the third group equipped but without compliance with the advice. Each traveler makes route choice in a logit‐based manner and a stochastic user equilibrium with multiple user classes is reached for every day. In this paper, we propose a model to investigate the evolutions of daily path travel time, daily ATIS compliance rate and yearly ATIS adoption, in which the equilibrium for every day's route choice is kept. The stability of the evolution model is initially analyzed. Numerical results obtained from a test network are presented for demonstrating the model's ability in depicting the day‐to‐day and year‐to‐year evolutions.
Multiple objective optimization of the fleet sizing problem for road freight transportation
Authors: Zak Jacek , Redmer Adam , Sawicki Piotr
Published: January 2010

A fleet sizing problem (FSP) in a road freight transportation company with heterogeneous fleet and its own technical back‐up facilities is considered in the paper. The mathematical model of the decision problem is formulated in terms of multiple objective mathematical programming based on queuing theory. Technical and economical criteria as well as interests of different stakeholders are taken into account in the problem formulation. The solution procedure is composed of two steps. In the first one a sample of Pareto‐optimal solutions is generated by an original program called MEGROS. In the second step this set is reviewed and evaluated, according to the Decision Maker's (DM's) model of preferences. The evaluation of solutions is carried out with an application of an interactive multiple criteria analysis method, called Light Beam Search (LBS). Finally, the DM selects the most desirable, compromise solution.
General stochastic user equilibrium traffic assignment problem with link capacity constraints
Authors: Meng Qiang , Lam William H. K. , Yang Liu
Published: January 2010

This paper addresses a general stochastic user equilibrium (SUE) traffic assignment problem with link capacity constraints. It first proposes a novel linearly constrained minimization model in terms of path flows and then shows that any of its local minimums satisfies the generalized SUE conditions. As the objective function of the proposed model involves path‐specific delay functions without explicit mathematical expressions, its Lagrangian dual formulation is analyzed. On the basis of the Lagrangian dual model, a convergent Lagrangian dual method with a predetermined step size sequence is developed. This solution method merely invokes a subroutine at each iteration to perform a conventional SUE traffic assignment excluding link capacity constraints. Finally, two numerical examples are used to illustrate the proposed model and solution method.
Passengers' perceptions and effects of bus‐holding strategy using automatic vehicle location technology
Authors: Hanaoka Shinya , Qadir Fayyaz Mahmood
Published: January 2010

This study reports bus passengers' behavior and perceptions related to the use of potential features of an automatic vehicle location (AVL) system in bus transit through conducting an attitudinal on‐board survey in Bangkok. A passenger waiting‐time survey conducted as part of this study revealed that passengers perceive waiting‐time at bus stops to be greater than actually experienced. The other aim of this study is to examine the potential benefits of bus‐holding using an AVL technology, in terms of waiting‐time, through minimizing bus bunching under different congestion levels. The results are obtained using PARAMICS, and reveal a significant reduction in average waiting‐time.
PEGylation of therapeutic proteins
Authors: Jevševar Simona , Kunstelj Menči , Porekar Vladka Gaberc
Published: January 2010

Since the first PEGylated product was approved by the Food and Drug Administration in 1990, PEGylation has been widely used as a post‐production modification methodology for improving biomedical efficacy and physicochemical properties of therapeutic proteins. Applicability and safety of this technology have been proven by use of various PEGylated pharmaceuticals for many years. It is expected that PEGylation, as the most established technology for extension of drug residence in the body, will play an important role in the next generation therapeutics, such as peptides, protein nanobodies and scaffolds, which due to their diminished molecular size need half‐life extension. This review focuses on several factors important in the production of PEGylated biopharmaceuticals enabling efficient preparation of highly purified PEG‐protein conjugates that have to meet stringent regulatory criteria for their use in human therapy. Areas addressed are PEG properties, the specificity of PEGylation reactions, separation and large‐scale purification, the availability and analysis of PEG reagents, analysis of PEG‐protein conjugates, the consistency of products and processes and approaches used for rapid screening of pharmacokinetic properties of PEG‐protein conjugates.
Feasibility and safety of radiofrequency ablation for locally advanced pancreatic cancer
Authors: Girelli R , Frigerio I , Salvia R , Barbi E , Tinazzi Martini P , Bassi C
Published: January 2010

Background

Radiofrequency ablation (RFA) may be a valuable treatment option for locally advanced pancreatic cancer. The present study examined its feasibility and safety.

Methods

Fifty patients with locally advanced pancreatic cancer were studied prospectively. Ultrasound-guided RFA was performed during laparotomy. The main outcome measures were short-term morbidity and mortality.

Results

The tumour was located in the pancreatic head or uncinate process in 34 patients and in the body or tail in 16; median diameter was 40 (interquartile range 30–50) mm. RFA was the only treatment in 19 patients. RFA was combined with biliary and gastric bypass in 19 patients, gastric bypass alone in eight, biliary bypass alone in three and pancreaticojejunostomy in one. The 30-day mortality rate was 2 per cent. Abdominal complications occurred in 24 per cent of patients; in half they were directly associated with RFA and treated conservatively. Three patients with surgery-related complications needed reoperation. Reduction of RFA temperature from 105 °C to 90 °C resulted in a significant reduction in complications (ten versus two of 25 patients; P = 0·028). Median postoperative hospital stay was 10 (range 7–31) days.

Conclusion

RFA of locally advanced pancreatic cancer is feasible and relatively well tolerated, with a 24 per cent complication rate.
Operative mortality after gastric cancer resection and long-term survival differences across Europe
Authors:   EUROCARE working group, Lepage C , Sant M , Verdecchia A , Forman D , Esteve J , Faivre J
Published: January 2010

Background

Little is known at a population level about operative mortality after surgery for gastric cancer and whether differences between countries can explain differences in long-term survival. This study compared operative mortality recorded by ten cancer registries in seven European countries.

Methods

Non-conditional logistic regression analysis was performed to estimate the independent effect of the studied factors on mortality within 30 days of surgery. A multivariable survival model was employed with and without operative mortality.

Results

The overall operative mortality rate in 1611 patients studied was 8·9 (range 5·2–16) per cent. Country of residence was a significant prognostic factor in the multivariable analysis. The likelihood of operative mortality was lower in Italy, France and the UK than in the Netherlands, Spain, Slovenia and Poland. Age, type of gastrectomy and stage at diagnosis were also significant factors. Cancer site was not found to be significant in the multivariable analysis. The overall 5-year relative survival rate varied between 42·0 per cent (Italy) and 24 per cent (Poland); after excluding operative mortality, the 5-year survival rate was 44·3 and 28 per cent respectively.

Conclusion

Within Europe, the substantial differences in operative mortality after gastrectomy only partly explain marked differences in survival after gastric cancer resection.
Simultaneous determination of lamivudine, stavudine and nevirapine in human plasma by LC–MS/MS and its application to pharmacokinetic study in clinic
Authors: Li Zhou , Ding Cungang , Ge Qinghua , Zhou Zhen , Zhi Xiaojin , Liu Xiaofen
Published: January 2010

A new high‐throughput LC–MS/MS method for the simultaneous determination of lamivudine (3TC), stavudine (d4T) and nevirapine (NVP) in human plasma is presented, with zidovudine as an internal standard. The analytes were extracted from plasma by protein precipitation and only 150 μL plasma was needed. Chromatographic separation was achieved on a Shiseido C8 column (150 × 2.0 mm, 5 μm) with a total run time of 6 min. A tandem mass spectrometric detection was conducted using multiple reaction monitoring under positive ionization mode with an electrospray ionization interface. The method was developed and validated over the concentration range of 25–5000 ng/mL for 3TC and NVP and 20–4000 ng/mL for d4T. The method was validated in terms of intra‐ and inter‐day precision (≤8.6%), accuracy (within ± 8.4%), linearity and specificity. The method has been successfully applied to the pharmacokinetic study of a combination treatment of 300 mg lamivudine, 30 mg stavudine and 200 mg nevirapine in 22 healthy male volunteers under fasting conditions. Copyright © 2010 John Wiley & Sons, Ltd.
An improved LC‐MS/MS method for simultaneous determination of 1,5‐dicaffeoylquinic acid and its active metabolites in human plasma and its application to a pharmacokinetic study in patients
Authors: Liu Jianglin , Dou Guifang , Dong Xiaona , Yuan Dan , Ji Xiwei , Wu Zhuona , Meng ZhiYun
Published: January 2010

In this study, a sensitive, selective and reproducible liquid chromatography–tandem mass spectrometry method for the simultaneous determination of 1,5‐dicaffeoylquinic acid (1,5‐DCQA) and its active metabolites, 1‐caffeoyl‐5‐feruoylquinic acid and 1,5‐O‐diferuoylquinic acid, in human plasma, using puerarin as internal standard, was developed and validated. Analytes were extracted from plasma samples by liquid–liquid extraction with ethyl acetate, separated on a C18reversed‐phase column with water containing 5 mM ammonium acetate and acetonitrile as the mobile phase and detected by electrospray ionization mass spectrometry in negative selected reaction monitoring mode. The accuracy and precision of the method were acceptable and linearity was good over the range 1–200 ng/mL for each analyte. In addition, the selectivity, extraction recovery and matrix effect were satisfactory too. The validated LC‐MS/MS method was successfully applied to phase II clinical pharmacokinetic study of 1,5‐DCQA in patients. Copyright © 2010 John Wiley & Sons, Ltd.
Anatomic variation of the clavicle: A novel three‐dimensional study
Authors: Daruwalla Zubin J. , Courtis Patrick , Fitzpatrick Clare , Fitzpatrick David , Mullett Hannan
Published: January 2010

An understanding of the complex anatomy of the clavicle is helpful in the treatment of clavicular fractures. Using three‐dimensional (3D) statistical shape analysis, the author presents a novel method to assess geometric morphology of the clavicle. Fifteen fresh frozen shoulder specimens were scanned using high‐resolution computerized tomography (CT) but four were excluded from the study. A further 16 high‐resolution CT scans of the clavicle were obtained by searching the hospital database. All 27 scans were reconstructed and subsequently imported into and analyzed using a specifically developed statistical software package. Using statistical shape analysis, geometric parameters were then measured. Both gender as well as side specific geometric morphology were observed. Clavicles in men were longer, wider, and thicker than in women. Right clavicles had a greater medial depth than left clavicles, especially in women. Clavicles in men had a greater lateral depth than in women. The sternal angle in women was larger than in men. Using 3D statistical shape analysis and applying it to the clavicle standardizes the study of its anatomy, rules out any variability, and calculates morphological parameters that are accurate, precise, and reproducible. This unique approach provides information that is useful not only to the clinician but also in the modification of current or design of future clavicle fixation devices. More importantly, from an anatomy standpoint, implementation of this novel approach in anatomical studies would eliminate intra‐ and interobserver variation and allow all studies to be standardized and thus more comparable. Clin. Anat. 23:199–209, 2010. © 2010 Wiley‐Liss, Inc.
A quantitative analysis of variability in brachial plexus anatomy
Authors: Fetty L.K. , Shea J. , Toussaint C.P. , McNulty J.A.
Published: January 2010

The aim of this study was to quantify the lengths of nerve segments within the brachial plexus. Twenty cadavers were dissected bilaterally, giving a total of 40 brachial plexuses for measurement. Individual lengths of plexus segments were measured and recorded, and means and standard deviations were calculated for all data. Differences between the means were statistically evaluated using the Student's t‐test. Only 3 of 16 segments were found to be longer in women on average, which included the anterior division of the superior trunk, the anterior division of the middle trunk and the posterior division of the inferior trunk. All three cords (medial, lateral, and posterior) were found to be significantly different between genders, the longer segments being in males. Significant bilateral differences were also observed when right and left brachial plexuses from each cadaver were compared. Extra lateral heads (ELHs) to the median nerve were found in 50% of brachial plexuses, the anatomy of which varied bilaterally as well as between genders. Awareness of this variability is important both to anatomists and to clinicians who operate on and around the brachial plexus. Clin. Anat. 23:210–215, 2010. © 2010 Wiley‐Liss, Inc.
Solid‐state Materials and Methods for Hydrogen Storage: A Critical Review
Authors: Lim K. L. , Kazemian H. , Yaakob Z. , Daud W. R. W.
Published: January 2010

Hydrogen is important as a new source of energy for automotive applications. It is clear that the key challenge in developing this technology is hydrogen storage. Current methods for hydrogen storage have yet to meet all the demands for on‐board applications. High‐pressure gas storage or liquefaction cannot fulfill the storage criteria required for on‐board storage. Solid‐state materials have shown potential advantages for hydrogen storage in comparison to other storage methods. In this article, the most popular solid‐state storage materials and methods including carbon based materials, metal hydrides, metal organic frameworks, hollow glass microspheres, capillary arrays, clathrate hydrates, metal nitrides and imides, doped polymer and zeolites, are critically reviewed. The survey shows that most of the materials available with high storage capacity have disadvantages associated with slow kinetics and those materials with fast kinetics have issues with low storage capacity. Most of the chemisorption‐based materials are very expensive and in some cases, the hydrogen absorption/desorption phenomena is irreversible. Furthermore, a very high temperature is required to release the adsorbed hydrogen. On the other hand, the main drawback in the case of physisorption‐based materials and methods is their lower capacity for hydrogen storage, especially under mild operating conditions. To accomplish the requisite goals, extensive research studies are still required to optimize the critical parameters of such systems, including the safety (to be improved), security (to be available for all), cost (to be lowered), storage capacity (to be increased), and the sorption‐desorption kinetics (to be improved).
Heteroscedastic controlled calibration model applied to analytical chemistry
Authors: Blas Betsabé , Sandoval Mônica C.
Published: January 2010

In chemical analyses performed by laboratories, one faces the problem of determining the concentration of a chemical element in a sample. In practice, one deals with the problem using the so‐called linear calibration model, which considers that the errors associated with the independent variables are negligible compared with the former variable. In this work, a new linear calibration model is proposed assuming that the independent variables are subject to heteroscedastic measurement errors. A simulation study is carried out in order to verify some properties of the estimators derived for the new model and it is also considered the usual calibration model to compare it with the new approach. Three applications are considered to verify the performance of the new approach. Copyright © 2010 John Wiley & Sons, Ltd.
Analysis of a mechanical heart valve prosthesis and a native venous valve: Two distinct applications of FSI to biomedical applications
Authors: Narracott A. J. , Zervides C. , Diaz V. , Rafiroiu D. , Lawford P. V. , Hose D. R.
Published: January 2010

This paper reports the application of two commercial codes to the study of distinct cardiovascular problems: dynamics of a mechanical heart valve prosthesis and function of a native venous valve. The choice of code is driven by the characteristics of the problem. The ANSYS‐CFX implicit finite volume code is employed for the mechanical valve where the solution is dominated by the interaction between the local fluid domain and the rigid valve leaflets. The LS‐DYNA explicit dynamics code is used due to the stability of this approach when applied to systems with very flexible structural components such as the leaflets of a venous valve. The mechanical valve dynamics remain consistent for a range of mesh densities and residual criteria but begin to vary once the solution time step is increased above 2E–4 s. Venous valve function after application of a gravitational body load is shown to be dependent on parent vessel elastic modulus, E. The venous valve initially closes to a greater extent with a ‘softer’ parent vessel. Both approaches show promise for further study of these biomedical systems including the cavitation and thrombotic potential of mechanical valves and the local residence of blood constituents in the region of venous valve sinuses. Copyright © 2009 John Wiley & Sons, Ltd.