bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal and economical optimization for a finned-tube, air-cooled condenser design of a roof-top bus air-conditioning system
Authors: Mansour M Khamis , Musa M N , Wan Hassan M N
Published: November 2007

The current paper presents a methodology of a design optimization technique that can be useful in assessing the best configuration of a finned-tube condenser, using a thermal and economical optimization approach. The assessment has been carried out on an air-cooled finned-tube condenser of a vapour compression cycle for a roof-top bus air-conditioning system at a specified cooling capacity. The methodology has been conducted by studying the effect of some operational and geometrical design parameters for the condenser on the entire cycle exergy destruction or irreversibility, air-conditioning system coefficient of performance (COP), and total annual cost. The heat exchangers for the bus air-conditioning system are featured by a very compact frontal area due to the stringent space limitations and structure standard for the system installation. Therefore, the current study also takes in its account the effect of the varying design parameters on the condenser frontal area. The irreversibility due to heat transfer across the stream-to-stream temperature-difference and due to frictional pressure-drops is calculated as a function of the design parameters. A cost function is introduced, defined as the sum of two contributions, the investment expense of the condenser material and the system compressor, and the operational expense of air-conditioning system, which is usually driven by an auxiliary engine or coupled with the main bus engine. The optimal trade-off between investment and operating cost is therefore investigated. A numerical example is discussed, in which, a comparison between the commercial condenser design and optimal design configuration has been presented in terms of the system COP and condenser material cost. The results show that a significant improvement can be obtained for the optimal condenser design compared to that of the commercial finned-tube condenser, which is designed based on the conventional values of the design parameters.
An investigation of the effects of lorry suspension performance on road maintenance costs
Authors: Costanzi M , Cebon D
Published: November 2007

A mathematical model of the interaction between a fleet of heavy vehicles and a spraysealed road surface is developed and validated using field performance data. Key features of the model include: (a) modelling the dynamic performance of the vehicle fleet using an ensemble of ‘quarter car’ vehicle models; (b) careful accounting for the ‘spatial repeatability’ of tyre forces; (c) use of accelerated pavement performance test data to model the evolution of the road surface profile; (d) surface maintenance intervention based on permanent deformation (rutting), potholing and excessive surface roughness. The model is used to predict long-term road maintenance intervention costs and to compare the predicted road maintenance costs for various suspension scenarios in the vehicle fleet.

The simulation results indicate that conversion of the heavy vehicle fleet from conventional leaf spring suspensions to ‘road-friendly’ suspensions would results in a reduction in road maintenance costs per tonne-km of 14 per cent. Increasing the freight load by 3.0 tonnes per vehicle would reduce this benefit to approximately 1 per cent. If the fleet was to have 50 per cent poorly maintained shock absorbers, the simulations show an increase in road maintenance expenditures per tonne-km: about 5 per cent higher than conventional suspensions at the lower weights and 21 per cent higher at the higher weights.
Identification of impact force on a thick plate based on the elastodynamic and higher-order time-frequency analysis
Authors: Lee S-K , Banerjee S , Mal A
Published: November 2007

The current paper presents a novel approach to precisely locate and characterize an impact load in thick plates. The approach is based on the analysis of the acoustic waveforms measured by a sensor array located on the plate surface in combination with the theoretical Green's function for the plate. The Green's functions are derived based on either the exact elastodynamic theory or an approximate shear deformation plate theory. For accurate estimation of the location of the impact source, the time differences in the arrival times of the waves at the sensors and their propagation velocities are determined first. This is accomplished through the use of a combined higher-order time-frequency (CHOTF) method, which is capable of detecting signals with lower signal to noise ratio compared with other available methods. Since most of the energy in the wave is carried by the flexural waves ( A0 mode), the group velocity of this mode is extracted using the CHOTF technique for estimating the impact source location. The estimates are shown to be in excellent agreement with the actual locations and time histories of the applied impact loads.
MATLAB-based rapid controller development platform for control applications
Authors: Chen C-Y , Shun Y-C , Cheng C-C , Liao P-S , Fang Z-C
Published: November 2007

Embedded controllers are increasingly popular in industrial applications since designing flexible control modules over them can rapidly provide a finished product with a low manufacturing cost. Hence, rapid controller prototyping for embedded controller has been presented to resolve obstacles to developing controllers quickly. However, most proposed methods are prohibitively expensive and are restricted in the choice of software and hardware, thus, making them infeasible for engineering applications with the considerations of performance and cost. To solve the aforementioned problems, this study adopts MATLAB/Simulink with Real-Time Workshop as an effective means of producing a rapid controller development platform (RCDP), in which the controller model is built by the graphical drive modules, and is verified in Simulink, and the executable code correspondent to the controller model is then automatically generated and transferred to the target system for testing and verification. Experimental results indicate that the automatic generated code for third order controller with 1 ms sampling rate and actual position tracking in the X-Y table motion control can typically achieve the desired performance. Thus the proposed RCDP can effectively and practically save the development time of controller designs, particularly in the experimental course related to control theory in the education.
Theoretical and experimental analysis of a partially textured thrust bearing with square dimples
Authors: Marian V. G. , Kilian M , Scholz W
Published: November 2007

Surface texturing has proved to be very efficient in full and mixed lubrication, reducing the friction coefficient and the wear rate of mating surfaces. By partially texturing the inlet zone of a thrust washer pad load carrying capacity is generated in the system. In the present paper, a partially textured thrust bearing with square dimples is analysed theoretically using a thermohydrodynamic model. The equations are solved numerically by the finite-difference method. The bearing was realized by the photolithographic method and the theoretical results (fluid film thickness and friction torque) were compared with the experimental data obtained on the test rig. It is found that an optimal number of 12 sectors maximize the load carrying capacity of the bearing. The optimal textured fraction, which maximizes the load carrying capacity is 0.5 on the circumferential direction and 0.9-1 on the radial direction. A good correlation was found between the theoretical and experimental results for the two measured parameters (fluid film thickness and friction torque).
An experimental investigation of various materials on thrust washer bearing operation
Authors: Jackson R. L. , Green I
Published: November 2007

The current research experimentally quantifies and maps the behaviour of various thrust washer configurations under various conditions. The bearings are tested at controlled loads and speeds for a governed period of time (up to 14 h) or until failure. The experimental results show that at some loads and speeds the bearing operates with a near full hydrodynamic film and under more harsh conditions it operates in the boundary lubrication regime. The experimental results indicate that coatings enhance performance by decreasing friction and thus decreasing the heat generated. By decreasing the generated heat, the physical mechanisms of thermoelastic instability and thermoviscous distress are less likely to occur. Using bronze will decrease the friction between the bearings, although it may also decrease the life of the bearing. However, using more than one round washer appears to not significantly benefit washer-bearing performance.
Derivation of non-Newtonian squeeze-film Reynolds equation between convex surfaces and application to two different cylinders
Authors: Lin J-R
Published: November 2007

The derivation of non-Newtonian squeeze-film Reynolds-type equation between two convex surfaces and its application are of interest in the present study. Based upon the Stokes micro-continuum theory, the non-Newtonian squeeze-film Reynolds-type equation between two convex surfaces is derived to take into account the effects of couple stresses resulting from the lubricant blended with various additives. This non-Newtonian squeeze-film Reynolds-type equation is applicable to squeeze-film bearings lubricated with couple stress fluids when the general upper film shape and the lower film shape are specified. To guide the use of the equation, the squeeze-film mechanism between two different cylinders of infinite width with non-Newtonian couple stress fluids is illustrated. Comparing with the Newtonian-lubricant case, the presence of non-Newtonian couple stresses provides an increase in the load-carrying capacity, and therefore lengthens the approaching time. In addition, the effects of couple stresses on the squeeze film characteristics are more pronounced at lower squeeze-film height with larger couple stress parameters and larger radius ratios of cylinders. As the value of radius ratio approaches infinity, the present results agree closely with those of the previous studies by Hamrock [6] and by Lin et al. [19], respectively; it provides a support to the present study.
Roughness in lubricated rolling contact: The dry contact limit
Authors: Olver A. V. , Dini D
Published: November 2007

A difficulty with the standard fast Fourier transform (FFT) perturbation model of roughness in lubricated rolling contacts is that it does not necessarily converge towards the elastic case as the film thickness is reduced; rather it leads to a situation in which all the roughness is completely flattened. This is rarely the case for real engineering surfaces.

Here, it is shown that this difficulty can be avoided by carrying out a Fourier transform of the elastostatically flattened roughness and using the resulting (complex) amplitude as the low-film thickness limit of each Fourier component in the elastohydrodynamic lubrication (EHL) analysis.

Results give a plausible convergence to the elastostatic solution, which is nevertheless consistent with the expected near-full-film EHL behaviour and which becomes identical to the earlier model for roughness that, statically, can be fully flattened. As expected, hydrodynamic action persists at the finest scale, even for very thin films.
Axial Load Behavior of Rectangular CFT Stub Columns with Binding Bars
Authors: Cai Jian , Long Yue-Ling
Published: November 2007

This paper presents an experimental study on the axial load behaviour of rectangular concrete-filled steel tubular (R-CFT) stub columns with binding bars. Eight specimens were concentrically loaded in compression to failure in order to investigate the effects of the binding bars, depth-to-wall thickness ratio and cross-sectional aspect ratio on the ultimate strength and ductility of the composite columns. Experimental results indicate that the binding bars increase the confinement of the concrete core and delay local buckling of the tube. The results also show that R-CFT columns with binding bars have better ductility than those without binding bars. A model is proposed to predict the ultimate strength of the specimens. A comparison of the ultimate strengths between tests and design codes shows that the proposed model gives reasonable predictions of the ultimate strength of rectangular CFT stub columns with binding bars while the codes EC4 (1996), AIJ (1997) and GJB (2001) conservatively estimate the ultimate strength by 17.6%, 22.9% and 9.7% respectively.
Flat Slabs at Slab-Column Connection: Nonlinear Finite Element Modelling and Punching Shear Capacity Design Criterion
Authors: Xiao R. Y. , Chin C. S.
Published: November 2007

Nonlinear finite element analysis has become very useful in modelling complicated structural systems and their behaviour. In this paper, an attempt has been made to utilize a tension softening material (TSM) model to simulate the full pre-cracking and post-cracking response of fibre reinforced concrete flat slabs at slab-column connections by finite element analysis. Validation of the developed numerical model was carried out by means of comparisons with test results. In addition, a universal analytical model has been proposed to predict the ultimate punching shear strength of slab-column connections. Compared with the relevant design codes (BS 8110, ACI 318–05, EC 2 1991, EC 2 2004/CEB-FIP MC90 and JSCE 1986), the model proposed herein has been shown to be accurate, with low coefficient of variation. Furthermore, a distinctive failure mode indicator has also been derived.
A Simplified Solution of the Torsional Rigidity of the Composite Beams by Using FEM
Authors: Saygun A. , Omurtag M. H. , Orakdogen E. , Girgin K. , Kucukarslan S. , Darilmaz K.
Published: November 2007

In this paper, the torsional rigidity of the composite sections formed by different materials is obtained by using a finite element procedure. In the derivation of the differential equation, the Saint-Venant's stress function was used. The obtained partial differential equation was discretized by finite elements to get the potentials in the nodal points. After the calculations of the unknown potentials on the composite cross-section, the torsional rigidity is calculated by integrating the potentials on the solution domain. To test the validity of the proposed algorithm, the available analytical and numerical results from the previous studies were studied. It was seen that this new algorithm is efficient and simpler than the previous ones.
Effect of a Dent of Different Sizes and Angles of Inclination on Buckling Strength of a Short Stainless Steel Cylindrical Shell Subjected to Uniform Axial Compression
Authors: Prabu B. , Bujjibabu N. , Saravanan S. , Venkatraman A.
Published: November 2007

Generally, thin cylindrical shells are susceptible for geometrical imperfections like non-circularity, non-cylindricity, dents, swellings etc. All these geometrical imperfections decrease the static buckling strength of thin cylindrical shells, but in this paper only effect of a dent on strength of a short (L / D ∼1 and R/t = 280) stainless steel cylindrical shell is considered for analysis. The dent is modeled on the FE surface of perfect cylindrical shell for different angles of inclination and sizes at half the height of cylindrical shell. The cylindrical shells with a dent are analyzed using non-linear static buckling analysis. From the results it is found that in case of shorter dents, size and angle of inclination dents do not have much effect on static buckling strength of thin cylindrical shells, where as in the case of long dents, size and angle of inclination of dents have significant effect. But both short and long dents reduce the static buckling strength drastically.
Semi-Active Stiffness Dampers for Seismic Control of Structures
Authors: Kori Jagadish G. , Jangid R. S.
Published: November 2007

This paper describes the application of semi-active variable stiffness damper (SAVSD) for response control of the seismically excited structure. The SAVSD consists of hydraulic damper connected in the form of bracing in a selected story of frame structure. The SAVSD changes its stiffness depending upon the structural response and accordingly adds the control forces in the structural system. In this paper, the comparative study and the performance of SAVSD under different ratios of damper stiffness to structural story stiffness is presented. The specific objective of this study is to evaluate the optimum value of damper stiffness ratio and its importance in structural response reduction. The optimum stiffness ratio is investigated for the structure subjected to four different types of earthquake ground motions. Here, the switching control law and newly proposed modified switching control law are used and the results are compared with uncontrolled and passive control cases. A numerical study is performed on five and ten-story shear building with different configurations of damper placement. The numerically evaluated optimum parametric values are considered for the analysis of the optimum damper placement in the structure. It is revealed that, the proposed modified switching control law is very effective in reducing the story displacements and inter-story drifts without increasing the top floor accelerations. The numerical results of various analyses indicate that SAVSD shows better performance over the passive dampers in reducing the structural responses.
A Different Ball Game—Why the Nature of Consent in Contact Sports Undermines a Unitary Approach
Authors: Livings Ben
Published: November 2007

The criminal offences to which consent may act as a defence fall into three distinct groups: those against property, sexual offences against the person and non-sexual offences against the person. This article posits a counterpoint to calls for a consistent application of the defence across the various offences to which it may apply, exploring the role of consent as it applies as a defence to violent criminal assaults, and particularly those committed during sport. It further examines the way in which the civil courts have approached consent in largely similar contexts, when assessing claims in negligence arising from personal injury caused by violence in the sporting arena, and juxtaposes and compares the civil and criminal approaches. Sport can provide problematic and anomalous situations with regard to the law, and it is submitted that this is better acknowledged in the civil law, where the courts have more readily considered revisions to substantive legal principles.
Arsenic Speciation Analysis in Human Saliva
Authors: Yuan Chungang , Lu Xiufen , Oro Nicole , Wang Zhongwen , Xia Yajuan , Wade Timothy J , Mumford Judy , Le X Chris
Published: November 2007

Background: Determination of arsenic species in saliva is potentially useful for biomonitoring of human exposure and studying arsenic metabolism. Arsenic speciation in saliva has not been reported previously.

Methods: We separated arsenic species in saliva using liquid chromatography (LC) and quantified them by inductively coupled plasma mass spectrometry. We further confirmed the identities of arsenic species by LC coupled with electrospray ionization tandem mass spectrometry. These methods were successfully applied to the determination of arsenite (AsIII), arsenate (AsV), and their methylation metabolites, monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV), in >300 saliva samples collected from people who were exposed to varying concentrations of arsenic.

Results: The mean (range) concentrations (μg/L) in the saliva samples from 32 volunteers exposed to background levels of arsenic were AsIII 0.3 [not detectable (ND) to 0.7], AsV 0.3 (ND to 0.5), MMAV 0.1 (ND to 0.2), and DMAV 0.7 (ND to 2.6). Samples from 301 people exposed to increased concentrations of arsenic in drinking water showed detectable AsIII in 99%, AsV in 98%, MMAV in 80%, and DMAV in 68% of samples. The mean (range) concentrations of arsenic species in these saliva samples were (in μg/L) AsIII 2.8 (0.1–38), AsV 8.1 (0.3–120), MMAV 0.8 (0.1–6.0), and DMAV 0.4 (0.1–3.9). Saliva arsenic correlated with drinking water arsenic. Odds ratios for skin lesions increased with saliva arsenic concentrations. The association between saliva arsenic concentrations and the prevalence of skin lesions was statistically significant (P <0.001).

Conclusions: Speciation of AsV, AsIII, MMAV, and DMAV in human saliva is a useful method for monitoring arsenic exposure.
Latent MMP-9 is bound to TIMP-1 before secretion
Authors: Roderfeld Martin , Graf Jürgen , Giese Bernd , Salguero-Palacios Rebeca , Tschuschner Annette , Müller-Newen Gerhard , Roeb Elke
Published: November 2007

Expression patterns of matrix metalloproteinase-9 (MMP-9) and its specific inhibitor, tissue inhibitor of metalloproteinases-1 (TIMP-1), are closely correlated with physiological and pathological processes characterized by the degradation and accumulation of the extracellular matrix (ECM). Both, activated MMP-9 and pro-MMP-9 can bind to TIMP-1, and most cell types secrete MMP-9 in complex with TIMP-1. Utilizing immunofluorescence, we observed intracellular co-localization of MMP-9 and TIMP-1 in stimulated human fibrosarcoma cells. In the present study we searched for the origin of the complex formation between the latent enzyme and its specific inhibitor on a subcellular level. Fluorescence resonance energy transfer (FRET) between the fluorescently labeled enzyme and its inhibitor in co-transfected cells were measured. MMP-9 and TIMP-1 were fused to cyan (CFP) and yellow (YFP) variants of the green fluorescent protein and transiently expressed in human hepatoma cells. The intracellular distribution of fluorescently labeled TIMP-1 and MMP-9 was analyzed by confocal laser scanning microscopy. Intracellular complex formation in the Golgi apparatus was verified, demonstrating FRET between MMP-9-CFP and TIMP-1-YFP. Our data provide evidence that the proMMP-9-TIMP-1 complex is already present in the Golgi apparatus. This may be of significance for a number of intracellular and extracellular biochemical processes involving proMMP-9. However, the magnitude and functional relevance of this finding remain unknown.
Defining the extended substrate specificity of kallikrein 1-related peptidases
Authors: Borgoño Carla A. , Gavigan Julie-Ann , Alves Juliano , Bowles Ben , Harris Jennifer L. , Sotiropoulou Georgia , Diamandis Eleftherios P.
Published: November 2007

Human kallikrein 1-related peptidases (KLKs) form a subfamily of 15 extracellular (chymo)tryptic-like serine proteases. KLKs 4, 5, 13 and 14 display altered expression/activity in diverse pathological conditions, including cancer. However, their distinct (patho)physiological roles remain largely uncharacterized. As a step toward distinguishing their proteolytic functions, we attempt to define their primary and extended substrate specificities and identify candidate biological targets. Heterologously expressed KLKs 4, 5, 13 and 14 were screened against fluorogenic 7-amino-4-carbamoylmethylcoumarin positional scanning-synthetic combinatorial libraries with amino acid diversity at the P1–P4 positions. Our results indicate that these KLKs share a P1 preference for Arg. However, each KLK exhibited distinct P2–P4 specificities, attributable to structural variations in their surface loops. The preferred P4–P1 substrate recognition motifs based on optimal subsite occupancy were as follows: VI-QSAV-QL-R for KLK4; YFWGPV-RK-NSFAM-R for KLK5; VY-R-LFM-R for KLK13; and YW-KRSAM-HNSPA-R for KLK14. Protein database queries using these motifs yielded many extracellular targets, some of which represent plausible KLK substrates. For instance, cathelicidin, urokinase-type plasminogen activator, laminin and transmembrane protease serine 3 were retrieved as novel putative substrates for KLK4, 5, 13 and 14, respectively. Our findings may facilitate studies on the role of KLKs in (patho)physiology and can be used in the development of selective KLK inhibitors.
Characterization and comparative 3D modeling of CmPI-II, a novel ‘non-classical’ Kazal-type inhibitor from the marine snail Cenchritis muricatus (Mollusca)
Authors: González Yamile , Pons Tirso , Gil Jeovanis , Besada Vladimir , Alonso-del-Rivero Maday , Tanaka Aparecida S. , Araujo Mariana S. , Chávez María A.
Published: November 2007

The complete amino acid sequence obtained by electrospray ionization tandem mass spectrometry of the proteinase inhibitor CmPI-II isolated from Cenchritis muricatus is described. CmPI-II is a 5480-Da protein with three disulfide bridges that inhibits human neutrophil elastase (HNE) (K
i 2.6±0.2 nM), trypsin (K
i 1.1±0.9 nM), and other serine proteinases such as subtilisin A (K
i 30.8±1.2 nM) and pancreatic elastase (K
i 145.0±4.4 nM); chymotrypsin, pancreatic and plasma kallikreins, thrombin and papain are not inhibited. CmPI-II shares homology with the Kazal-type domain and may define a new group of ‘non-classical’ Kazal inhibitors according to its CysI-CysV disulfide bridge position. The 3D model of CmPI-II exhibits similar secondary structure characteristics to Kazal-type inhibitors and concurs with circular dichroism experiments. A 3D model of the CmPI-II/HNE complex provides a structural framework for the interpretation of its experimentally determined K
i value. The model shows both similar and different contacts at the primary binding sites in comparison with the structure of turkey ovomucoid third domain (OMTKY3)/HNE used as template. Additional contacts calculated at the protease-inhibitor interface could also contribute to the association energy of the complex. This inhibitor represents an exception in terms of specificity owing to its ability to strongly inhibit elastases and trypsin.
Novel expression of kallikreins, kallikrein-related peptidases and kinin receptors in human pleural mesothelioma
Authors: Chee Jessica , Singh Jasmine , Naran Anupam , Misso Neil L. , Thompson Philip J. , Bhoola Kanti D.
Published: November 2007

Malignant mesothelioma is an aggressive cancer of the pleura that is causally related to exposure to asbestos fibres. The kallikrein serine proteases [tissue (hK1) and plasma (hKB1) kallikreins, and kallikrein-related peptidases (KRP/hK2–15)] and the mitogenic kinin peptides may have a role in tumourigenesis. However, it is not known whether hK1, hKB1, KRP/hK proteins or kinin receptors are expressed in pleural mesotheliomas. The expression of hK1, hKB1, KRP/hK2, 5, 6, 7, 8 and 9, and kinin B1and B2receptors was assessed in archived selected normal tissue and mesothelioma tumour sections by immunoperoxidase and immunofluorescence labelling. hK1, hKB1 and kinin B1and B2receptors were expressed in malignant cells of the epithelioid and sarcomatoid components of biphasic mesothelioma tumour cells. The percentage of cells with cytoplasmic and nuclear labelling and the intensity of labelling were similar for hK1, hKB1 and the kinin receptors. KRP/hK2, 6, 8 and 9 were also expressed in the cytoplasm and nuclei of mesothelioma cells, whereas KRP/hK5 and hK7 showed predominantly cytoplasmic localisation. This is a first report, but further studies are required to determine whether these proteins have a functional role in the pathogenesis of mesothelioma and/or may be potential biomarkers for pleural mesothelioma.
Cellular localization of MAGI-1 caspase cleavage products and their role in apoptosis
Authors: Ivanova Saška , Repnik Urška , Banks Lawrence , Turk Vito , Turk Boris
Published: November 2007

MAGI-1 is a membrane-associated guanylate kinase (MAGUK) protein present at adherent and tight junctions, where it acts as a structural and signaling scaffold. During apoptosis, MAGI-1 is cleaved by caspases at Asp761 into N- and C-terminal cleavage products, allowing further dismantling of the cell junctions, one of the key features of apoptosis. Here, we investigated the cellular distribution and possible proapototic role of MAGI-1 caspase cleavage products. Full-length MAGI-1 exhibited submembrane localization, while the N-terminal caspase cleavage product of MAGI-1 is translocated to the cytosol and the C-terminal caspase cleavage product accumulates in the nucleus. When overexpressed in MDCK cells, both N- and C-terminal MAGI-1 caspase cleavage products exhibited minor proapoptotic activity, although their role in apoptosis is probably more passive.
Activity of ulilysin, an archaeal PAPP-A-related gelatinase and IGFBP protease
Authors: Tallant Cynthia , García-Castellanos Raquel , Marrero Aniebrys , Canals Francesc , Yang Yongzheng , Reymond Jean-Louis , Solà Maria , Baumann Ulrich , Gomis-Rüth F. Xavier
Published: November 2007

Human growth and development are conditioned by insulin-like growth factors (IGFs), which have also implications in pathology. Most IGF molecules are sequestered by IGF-binding proteins (IGFBPs) so that exertion of IGF activity requires disturbance of these complexes. This is achieved by proteolysis mediated by IGFBP proteases, among which the best characterised is human PAPP-A, the first member of the pappalysin family of metzincins. We have previously identified and studied the only archaeal homologue found to date, Methanosarcina acetivorans ulilysin. This is a proteolytically functional enzyme encompassing a pappalysin catalytic domain and a pro-domain involved in maintenance of latency of the zymogen, proulilysin. Once activated, the protein hydrolyses IGFBP-2 to -6 and insulin chain β in vitro. We report here that ulilysin is also active against several other substrates, viz (azo)casein, azoalbumin, and extracellular matrix components. Ulilysin has gelatinolytic but not collagenolytic activity. Moreover, the proteolysis-resistant skeletal proteins actin and elastin are also cleaved, as is fibrinogen, but not plasmin and α1-antitrypsin from the blood coagulation cascade. Ulilysin develops optimal activity at pH 7.5 and strictly requires peptide bonds preceding an arginine residue, as determined by means of a novel fluorescence resonance energy transfer assay, thus pointing to biotechnological applications as an enzyme complementary to trypsin.
Cysteine proteases: destruction ability versus immunomodulation capacity in immune cells
Authors: Zavašnik-Bergant Tina , Turk Boris
Published: November 2007

Cysteine proteases (cathepsins) play a pivotal role in various physiological processes, as well as in several diseases. In the immune response, maturation of major histocompatibility class II (MHC II) molecules and processing of antigens for further presentation by MHC II is tightly linked to the enzymes of the endosomal/lysosomal system, of which cysteine proteases constitute a major proportion. Furthermore, the process of autophagy provides access for cytosolic antigens to proteolysis by lysosomal cathepsins and subsequent MHC II presentation. Other specific functions of proteolytic enzymes associated with the immune response, such as activation of granzymes by cathepsin C in T-lymphocytes, are introduced and covered in this review.
Protease research in the era of systems biology
Authors: Keller Ulrich auf dem , Doucet Alain , Overall Christopher M.
Published: November 2007

Proteases are specific modulators of signaling molecules and their underlying pathways in addition to their degradative roles. However, proteases do not act alone, but form cascades, circuits and networks that all dynamically interconnect to form the protease web, which defines the proteolytic potential of a cell or tissue in a defined condition. To describe the protease web and its net activity several novel high-throughput proteomic techniques, in the field termed degradomics, have been developed. Emerging systems biology methods to evaluate the expression, activity and substrate discovery of proteases are presented. Understanding the protease web and its perturbations in pathology will help to develop new therapeutics for the treatment of diseases, such as cancer, arthritis and chronic obstructive pulmonary diseases.
Association of cathepsin E with tumor growth arrest through angiogenesis inhibition and enhanced immune responses
Authors: Shin Masashi , Kadowaki Tomoko , Iwata Jun-ichi , Kawakubo Tomoyo , Yamaguchi Noriko , Takii Ryosuke , Tsukuba Takayuki , Yamamoto Kenji
Published: November 2007

Cathepsin E (CE) is an intracellular aspartic proteinase implicated in various physiological and pathological processes, yet its actual roles in vivo remain elusive. To assess the physiological significance of CE expression in tumor cells, human CE was stably expressed in human prostate carcinoma ALVA101 cells expressing very little CE activity. Tumor growth in nude mice with xenografted ALVA101/hCE cells was slower than with control ALVA101/mock cells. Angiogenesis antibody array and ELISA assay showed that this was partly due to the increased expression of some antiangiogenic molecules including interleukin 12 and endostatin in tumors induced by CE expression. In vitro studies also demonstrated that, among the cathepsins tested, CE most efficiently generated endostatin from the non-collagenous fragment of human collagen XVIII at mild acidic pH. Histological examination revealed that tumors formed by ALVA101/hCE cells were partitioned by well-developed membranous structures and covered with thickened, well-stratified hypodermal tissues. In addition, both the number and extent of activation of tumor-infiltrating macrophages were more profound in ALVA101/hCE compared to ALVA101/mock tumors. The chemotactic response of macrophages to ALVA101/hCE cells was also higher than that to ALVA/mock cells. These results thus indicate that CE expression in tumor cells induces tumor growth arrest via inhibition of angiogenesis and enhanced immune responses.
Two decades of thyroglobulin type-1 domain research
Authors: Mihelič Marko , Turk Dušan
Published: November 2007

Thyroglobulin type-1 repeats are primarily found in thyroglobulin and several other functionally unrelated proteins. Because a few of them exhibit inhibitory activity against cysteine proteases they were named thyropins (thyroglobulin type-1 domain protease inhibitors). In contrast to cystatins, the best-characterized group of papain-like protease inhibitors, they exhibit greater selectivity in their interactions with target proteases. Interestingly, a few members inhibit aspartic protease cathepsin D and metalloproteases. In contrast to the inhibitory fragment of the major histocompatibility complex class II-associated p41 form of invariant chain, whose structural integrity appears mandatory for its inhibitory properties, short polypeptides derived from insulin-like growth factor-binding proteins exhibit the same activity as the structure of the whole fragment. Taken together, the results indicate that the thyroglobulin type-1 repeat is a structural motif occasionally employed as an inhibitor of proteases.
Human and mouse homo-oligomeric meprin A metalloendopeptidase: substrate and inhibitor specificities
Authors: Bylander John E. , Bertenshaw Greg P. , Matters Gail L. , Hubbard Simon J. , Bond Judith S.
Published: November 2007

Meprin metalloproteinases have been implicated in the susceptibility to and progression of diabetic nephropathy and inflammatory bowel diseases. Our studies with experimental models of these diseases in mice are congruent with the conclusion that meprins modulate the inflammatory responses and tissue damage. To determine whether the mouse and human enzymes differ, recombinant forms of meprin A from the two species were compared with respect to structure, substrates and inhibitors. Human homo-oligomeric meprin A formed oligomers ranging from 950 000 to 1 500 000 Da vs. 900 000 Da for mouse meprin A. Human and mouse meprin A exhibited similar activity against azocasein, fibronectin, collagen IV, and peptides such as parathyroid hormone, ghrelin, and gastrin-releasing peptide. The human enzyme had lower activity against gelatin, bradykinin, α-melanocyte-stimulating hormone and neurotensin, and higher activity against secretin and orcokinin. Human meprin A showed a preference for acidic residues in the P1′ position of the substrate, unlike mouse meprin A. Several metalloproteinase inhibitors had IC50 values in the nanomolar range, but potency ranged from similar values to a difference of several orders of magnitude for meprins from the two species. This work provides valuable data to improve predictability for human systems based on meprin functions in mouse models.
Transformations of Wood in Costa Rican Artisan Traditions
Authors: Vargas Giselle Chang
Published: November 2007

Costa Rica is known for its biodiversity, evident in the variety of tropical woods available for elaboration into a wide range of objects. These include masks, bows and arrows, sculptures, troughs, furniture, yokes, wheels and oxcarts. Cultural diversity in wood products is manifest in diverse places of origin, ethnicities of woodworkers, and knowledge and techniques. Transformations proceed not only in the material—a piece of wood—but also in the sociocultural meanings of the object produced: traditional or innovative, change vs. continuity in domestic, decorative or ritual uses; function in work and play; and broader dimensions of commercialization, sustainability and identity.
Identity as Work: Changing Job Opportunities and Indigenous Identity in the Transition to a Tourist Economy
Authors: Stocker Karen
Published: November 2007

This article, based on ethnographic research carried out in the Chorotega indigenous reservation in northwestern Costa Rica between 1993 and 2007, traces the social and economic changes that have shifted the dominant trend from masking indigenous identity to embracing and promoting it. The growth of the tourism sector in areas near the reservation and the resulting participation by the Chorotega in heritage tourism have had repercussions on employment options for individuals on or from the reservation.
Valuing the “Professional” in an International Direct‐Selling Organization: The Commodification of Class Identity in Southern Costa Rica
Authors: Preston‐Werner Theresa
Published: November 2007

“4Life” is an American nutritional supplement company that entered Costa Rica in 2004. Its representatives portray their company as a provider of new forms of work and consumption that anyone can embrace, regardless of age, socioeconomic status or gender to enhance their material returns and social status. The appeal is especially strong for older women who increasingly face part‐time work, irregular scheduling and remuneration, and few or no fringe benefits. Informed by scholarship on work, consumption, and identity, this article combines a political economic perspective with a sociolinguistic approach in order to unpack the economic and social implications of employment in direct sales positions.
Stigmas of the Tamil Stage: An Ethnography of Special Drama Artists in South India
Authors: Johnson Leslie
Published: November 2007

Stigmas of the Tamil Stage: An Ethnography of Special Drama Artists in South India. Susan Seizer. Durham, NC: Duke University Press, 2005.
Worked Over: The Corporate Sabotage of an American Community
Authors: Dauria Susan R.
Published: November 2007

Worked Over: The Corporate Sabotage of an American Community. Dimitra Doukas. Ithaca and London: Cornell University Press, 2003.
Doormen
Authors: Walker Greg
Published: November 2007

Doormen. Peter Bearman. Chicago: University of Chicago Press, 2005.
The Pothunter's Livelihood: Huaquerismo and Costa Rican Law in Defense of the National Archaeological Heritage
Authors: Bonilla Mónica Aguilar
Published: November 2007

With legal mechanisms established to protect Costa Rica's archaeological heritage and to control the traffic in antiquities, the looting of sites has greatly diminished but not ceased. Designing measures that effectively end looting requires understanding of why and how it occurs. This article describes the activities of huaqueros during the second half of the twentieth century. Individuals no longer involved in illegal activities, but who “enjoy a certain prestige” based on their great experience, provide information about the work of huaqueros.
Indigenous Linguistics and Land Claims: The Semiotic Projection of Athabaskan Directionals in Elijah Smith's Radio Work
Authors: Moore Patrick
Published: November 2007

In recent decades, land claims and language revitalization have emerged as prominent forms of indigenous activism in many parts of the world. Activists' indigenous language performances merit special attention since they commonly foreground the semiotic resources of their languages and reference the social structures in which they are embedded. This article examines a co‐performance by Yukon native leader Elijah Smith and Southern Tutchone elder Solomon Charlie that epitomizes the use of indigenous linguistic resources to assert native rights and identity in innovative contexts. In particular, Charlie's account exemplifies the essential roles of deictic terms as bridges between micro‐level narrative processes and the macro‐level social fields of contemporary society in which indigenous identity is projected.
Book Reviews
Authors: Faudree Paja
Published: November 2007

Real Country: Music and Language in Working Class Culture. Aaron A. Fox. Durham, NC: Duke University Press, 2004. xv. 364 pp. Putting. Song on Top of It: Expression and Identity on the San Carlos Apache Reservation. David W. Samuels. Tucson: University of Arizona Press, 2004. x. 325 pp.
Book Reviews
Authors: Miller W. Flagg
Published: November 2007

Sacred Language, Ordinary People: Dilemmas of Culture and Politics in Egypt. Niloofar Haeri. New York: Palgrave Macmillan, 2003. xvi. 184 pp.
Book Reviews
Authors: Perrino Sabina
Published: November 2007

Intercultural Discourse and Communication: The Essential Readings. Scott Kiesling and Christina Bratt Paulston, eds. Malden, MA: Blackwell Publishing, 2005. xvi. 330 pp.
Book Reviews
Authors: Tuite Kevin
Published: November 2007

Dialect Change: Convergence and Divergence in European Languages. Peter Auer, Frans Hinskens, and Paul Kerswill, eds. Cambridge: Cambridge University Press., 2005. xiv. 415 pp. How New Languages Emerge. David Lightfoot, Cambridge: Cambridge University Press., 2006. ix. 199 pp.
A Cross-National Comparison of Racial and Ethnic Disparities in Low Birth Weight in the United States and England
Authors: Teitler Julien O. , Reichman Nancy E. , Nepomnyaschy Lenna , Martinson Melissa
Published: November 2007

OBJECTIVE. We used 2 new nationally representative surveys to compare racial and ethnic differences in low birth weight in the United States and England.

METHODS. Risk factors and rates of low birth weight were compared across groups for singleton births within each country (white, black, Hispanic, Asian, and American Indian mothers in the United States; white, black, and Asian mothers in England). Crude rates and rates adjusted for socioeconomic status and behaviors were compared. Additional comparisons were limited to native-born mothers.

RESULTS. Racial and ethnic disparities in low birth weight are as large in England as in the United States. Socioeconomic status and behaviors explain little of the variation across racial and ethnic groups in either country.

CONCLUSIONS. Health disadvantages associated with being a minority do not seem to be a uniquely American phenomenon. Universal health care, as provided in the United Kingdom, alone may be insufficient to reduce racial and ethnic disparities in low birth weight.
Voices of Asian American Youth: Important Characteristics of Clinicians and Clinical Sites
Authors: Vo Dzung X. , Pate Olivia Lee , Zhao Huaqing , Siu Philip , Ginsburg Kenneth R.
Published: November 2007

OBJECTIVE. The purpose of this work was to explore clinician and site characteristics that are important to Chinese and Vietnamese immigrant and first-generation youth.

METHODS. A 3-stage mixed qualitative-quantitative design consisting of exploratory focus groups, a survey, and explanatory focus groups was used to ensure that all of the ideas were generated, prioritized, and explained by youth. Adolescents of Chinese and/or Vietnamese descent and aged 13 to 18 years were recruited in community centers and schools. In stage 1, 55 adolescents in 8 focus groups shared their views on factors that attract or deter them from seeking care. In stage 2, youth responded to a survey including 27 teen-generated items regarding clinicians and sites. In stage 3, 87 teens in 11 groups explained the top-rated items and offered suggestions on how to meet their needs. All of the stages were conducted in English, Mandarin Chinese, and Vietnamese.

RESULTS. Most of the 245 survey respondents (77%) were born in Asia, and 70% had lived in the United States for <3 years. The 27 items were divided into 6 priority ranks by the marginal homogeneity test. Clinician cleanliness and experience shared first rank. Second rank was shared by Asian teens being treated like other teens, site cleanliness, clinician honesty, and clinician friendliness and attitude. The third rank was shared by respect, privacy, completeness, clinicians explaining their actions, and lower health care costs. Interspersed among ranks 5 and 6 were items specific to the needs of Asian youth: the clinician would offer more explanation because Asian families might not ask questions; the clinician would not assume that Asian teens are drug and sex free; the clinician would understand that Asian families may use traditional healing; the clinician would not assume that Asians do not know English; adolescents would not translate for parents; and the teen would be able to choose an Asian clinician. There was little variation in ratings by age, gender, ethnicity, or socioeconomic status. However, 11 of 27 items differed by acculturation. Examples include the greater importance ascribed by more acculturated youth to not being judged, to not having to translate, and to the clinician addressing behavioral issues. Acculturation also affected the youths' views regarding confidentiality and translation.

CONCLUSIONS. Asian American adolescents value the same concerns as all adolescents: respect, honesty, competency, cleanliness, privacy, and nonjudgmental service. However, they also have unique perspectives, and youth at varying levels of acculturation differ in some of their views.
A duodeno-gastrooesophagealis refluxbetegség sebészi kezelése: duodenal switch műtétr
Authors: Varga Gábor , Cseke László , Kalmár Katalin , Horváth Örs Péter
Published: November 2007

Absztrakt

A duodeno-gastrooesophagealis refluxbetegség komplex motilitási zavar, melynek kezelése (gyógyszeres és sebészi) mind a mai napig nem egységesen elfogadott. Tanulmányunk célja, hogy ismertessük a duodeno-gastrooesophagealis refluxbetegség kezelésével kapcsolatos tapasztalatainkat.

A tanulmányba azok a gastrooesophagealis refluxos betegek kerültek, akiknél terápiarezisztens epigastrialis panaszok, epés regurgitáció hátterében 24 órás kétcsatornás gyomor-, nyelőcső-Bilitec-vizsgálat kóros mértékű duodenogastricus refluxot igazolt. Mind a négy nőbetegnél (átlagéletkor 41,75 év (32–53)) duodenal switch műtétet végeztünk. A betegek 75%-ában korábban cholecystectomia történt. Az átlagos utánkövetési idő 24,25 (21–30) hónap volt.

Mind a 4 betegnél korábban gastrooesophagealis reflux betegség miatt antirefluxműtétre került sor. Közülük egy betegnél recidív gastrooesophagealis reflux is igazolódott, nála refundoplicatiót is végeztünk. Perioperatív szövődményt, mortalitást nem észleltünk. Utánkövetés során mind a négy beteg panaszmentessé vált, azonban egy betegnél az egyéves kontrollvizsgálat során végzett 24 órás nyelőcső-pH-monitorozás kóros mértékű savas refluxot igazolt.

Gastrooesophagealis reflux betegeknél antirefluxműtét után jelentkező epigastrialis panaszok hátterében kóros mértékű duodenogastricus reflux állhat. Erre prediszponáló tényező lehet a korábban elvégzett cholecystetomia. Gyógyszeres kezelésre nem javuló, funkcionális vizsgálatokkal igazolt kóros mértékű duodenogastricus reflux kezelésére duodenal switch műtét jó eredménnyel alkalmazható.