bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of Poly(ether‐block‐amide) Membranes
Authors: Mohammadi Toraj , Kikhavandi Towan , Moghbeli Mohammadreza
Published: April 2008

Poly(ether‐block‐amide) membranes were made via casting a solution on a nonsolvent (water) surface. In this research, effects of different parameters such as ratio of solvent mixture (n‐butanol/isopropanol), temperature, composition of coagulation bath (water) and polymer concentration, on quality of the thin film membranes were studied. The mechanism of membrane formation involves solution spreading, solvent–nonsolvent exchange, and partial evaporation of the solvent steps. Solvent‐ nonsolvent exchange is the main step in membrane formation and determines membrane morphology. However, at higher temperature of polymeric solution greater portion of solvent evaporates. The results showed that type of demixing process (mutual affinity between solvent and nonsolvent) has important role in film formation. Also, addition of solvent to the nonsolvent bath is effective on membrane morphology. The film quality enhances with increasing isopropanol ratio in the solvent mixture. This behavior can be related to increasing of solution surface tension, reduction of interfacial tension between solution and nonsolvent and delayed solvent‐nonsolvent demixing. Uniform films were made at a temperature rang of 60–80 °C and a polymer concentration of 4–7 wt%. Morphology of the membranes was investigated with scanning electron micrograph (SEM). Pervaporation of ethyl butyrate/water mixtures was studied using these membranes and high separation performance was achieved. For ethyl butyrate/water mixtures, It was observed that both permeation flux and separation factor increase with increasing ethyl butyrate content in the feed. Increasing temperature in limited range studied resulted in decreasing separation factor and increasing permeation flux.
The Curing Efficiency and Mechanical Properties of Light‐Activated Acrylic Resin
Authors: Channasanon Somruethai , Tanodekaew Siriporn
Published: April 2008

The aim of this investigation was to determine degree of conversion, and flexural and compressive strength of photocurable acrylic resin. The acrylic resins based on bis‐phenol A glycidyl dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) were formulated and then irradiated with red light to form a solid crosslinked polymer. Various post curing conditions were studied to investigate their effects on curing efficiency. Degree of conversion was analyzed by means of Fourier Transform Infrared Spectroscopy (FTIR) to monitor the quantity of remaining acrylic double bond in the cured resin. Three‐point bending and compressive strength were tested using Universal Testing Machine (UTM) to evaluate the mechanical performance. Our investigation demonstrated that the formulated acrylic resins were possibly polymerized under irradiation with red light and degree of conversion and mechanical properties were closely correlated.
Synthesis, Characterization and Biospecific Degradation Behavior of Sulfated Chitin
Authors: Jayakumar Rangasamy , Nwe Nitar , Nagagama Hideaki , Furuike Tetsuya , Tamura Hiroshi
Published: April 2008

Chitin is a polysaccharide found in the outer skeleton of insects, crabs, shrimps, and lobsters and in the internal structures of other invertebrates. Sulfated chitin was prepared by reacting carboxymethyl chitin (CM‐chitin) with 2‐aminoethane sulfonic acid by using 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC) catalyst. The prepared sulfated chitin was characterized by FTIR, elemental analysis, thermogravimetric analysis (TGA) and X‐ray diffraction (XRD). The degree of substitution was found to be 0.98 by elemental analysis. The TGA studies showed that sulfated chitin was less thermal stability than carboxymethyl chitin. This is due to the grafting reaction. The sulfated chitin membranes were prepared from sulfated chitin and then crosslink with glutaradehyde. The biodegradation process was performed in PBS (pH 7.4) containing lysozyme (10 µg/ml) at 37 °C in an incubator. Experimental results from weight loss throughout the study showed that the biospecific degradation occur on the membrane by lysozyme.
Polymeric Membrane Nanofiltration and Its Application to Separations in the Chemical Industries
Authors: Sereewatthanawut Issara , Boam Andrew T. , Livingston Andrew G.
Published: April 2008

The application of membrane technology, particularly water‐based nanofiltration, as a separation process in the chemical industries has increased tremendously in recent years. However, the use of membranes capable of molecular separation in non‐aqueous systems (e.g. nanofiltration) is a relatively new and growing application of membrane technology. The main challenge in applying polymeric nanofiltration membranes to non‐aqueous systems is that the polymers developed for water‐based applications are not suitable. Polyimide is a particularly interesting polymer as it has excellent chemical resistance, and membranes produced from it provide desirable separation properties – i.e. economically viable flux and good separation of nanoscale molecules. Various research works have shown that commercial polyimide organic solvent nanofiltration (OSN) membranes, trademark STARMEM™,1are robust and suitable for performing molecular separations. This work will discuss in detail the use of STARMEM™ in a pharmaceutical application. The EIC‐OSN process was developed for separating the enantiomers of chiral compounds in pharmaceutical applications. High optical purity (94.9%) of (S)‐phenylethanol fromrac‐phenylethanol was achieved through the use of STARMEM™122. Process simulation of the ideal eutomer‐distomer system predicted that the highest theoretical resolvability from this process would be 99.2%. Other application areas of OSN are varied, including purification and fractionation in the natural products industry, homogeneous catalyst recovery, monomer separation from oligomers, etc. Currently, OSN is used in a small number of processes including a very large petrochemical application, but it has the potential to be applied to a wide range of separations across the full spectrum of the chemical industries.
In vitro and in vivo evaluation of anticancer actions of natural and synthetic vitamin E forms
Authors: Yu Weiping , Jia Li , Wang Pei , Lawson Karla A. , Simmons‐Menchaca Marla , Park Sook‐Kyung , Sun LuZhe , Sanders Bob G. , Kline Kimberly
Published: April 2008

The goal of these studies was to investigate the potential anticancer properties of two naturally occurring plant sources and two manufactured synthetic forms of vitamin E, i. e., RRR‐α‐tocopherol (αT), RRR‐γ‐tocopherol (γT), all‐rac‐α‐tocopherol (all‐rac‐αT), and all‐rac‐α‐tocopheryl acetate (all‐rac‐αTAc) in breast cancer models. Vitamin E compounds were evaluated in vitro for inhibition of colony formation and induction of apoptosis in human MDA‐MB‐435 and MCF‐7 breast cancer cells and murine 66cl‐4 mammary cancer cells and in vivo for ability to reduce tumor growth and lung and lymph node metastases using the transplantable syngeneic BALB/c mouse 66cl‐4‐GFP mammary cancer model. γT inhibited colony formation and induced apoptosis in all three cancer cell lines. αT and all‐rac‐αT were less effective and all‐rac‐αTAc was ineffective. γT‐induced apoptosis was correlated with activation of caspases‐8 and ‐9 and down‐regulation of protein expression of c‐FLIP and survivin. In vivo study 1 analyses showed that all‐rac‐αT and all‐rac‐αTAc significantly inhibited tumor growth and inhibited both visible and microscopic size lung metastases. In vivo study 2 analyses showed that αT and γT reduced tumor growth, but only γT reduced tumor growth significantly in comparison to control. In conclusion, synthetic, but not natural, vitamin E exhibits promising anti‐cancer properties in vivo.
Absence of 2′‐deoxyguanosine‐carbon 8‐bound ochratoxin A adduct in rat kidney DNA monitored by isotope dilution LC‐MS/MS
Authors: Delatour Thierry , Mally Angela , Richoz Janique , Özden Sibel , Dekant Wolfgang , Ihmels Heiko , Otto Daniela , Gasparutto Didier , Marin‐Kuan Maricel , Schilter Benoît , Cavin Christophe
Published: April 2008

The contribution of DNA adduct formation in the carcinogenic action of the mycotoxin ochratoxin A (OTA) has been subject to much debate. Recently, a carbon‐bonded ochratoxin A‐2′‐deoxyguanosine adduct (dGuoOTA) formed by photochemical reaction in vitro has been shown by 32P‐postlabeling/TLC to comigrate with a spot detected in DNA isolated from rat and pig kidney following exposure to OTA. Considering the large body of evidence arguing against covalent DNA binding of OTA and the poor resolution and specificity of postlabeling analysis, we developed a stable isotope dilution LC‐MS/MS method to analyze dGuoOTA in kidney DNA isolated from rats treated with OTA. dGuoOTA and nitrogen‐15‐labeled dGuoOTA (15N5‐dGuoOTA) were prepared by photoirradiation of OTA in the presence of dGuo or nitrogen‐15‐labeled dGuo. Conditions for DNA hydrolysis were optimized using a synthetic oligonucleotide containing dGuoOTA to ensure complete release of dGuoOTA. The LOD of the method (S/N > 3) was 10 fmol dGuoOTA on‐column. However, dGuoOTA was not detected in DNA samples isolated from male F344 rats treated with OTA for up to 90 days at doses known to cause renal tumor formation. Detection limits, calculated for each individual sample based on the absolute LOD and the amount of DNA injected, were as low as 3.5 dGuoOTA/109 nucleotides. These data are consistent with previous results showing lack of DNA adduct formation by OTA and demonstrate that dGuoOTA is not formed in biologically relevant amounts under physiological conditions in vivo.
Analytical study of mine closure behaviour in a poro‐visco‐elastic medium
Authors: Wong H. , Morvan M. , Deleruyelle F. , Leo C. J.
Published: April 2008

This paper is interested in the hydro‐mechanical behaviour of an underground cavity abandoned at the end of its service life. It is an extension of a previous study that accounted for a poro‐elastic behaviour of the rock mass (Int. J. Comput. Geomech. 2007; DOI: 10.1016/j.compgeo.2007.11.003). Deterioration of the lining support with time leads to the transfer of the loading from the exterior massif to the interior backfill. The in situ material has a poro‐visco‐elastic constitutive behaviour while the backfill is poro‐elastic, both saturated with water. This loading transfer is accompanied by an inward cavity convergence, thereby compressing the backfill, and induces an outward water flow. This leads to a complex space–time evolution of pore pressures, displacements and stresses, which is not always intuitive. In its general setting, a semi‐explicit solution to this problem is developed, using Laplace transform, the inversion being performed numerically. Analytical inversion leading to a quasi‐explicit solution in the time domain is possible by identifying the characteristic creep and relaxation times of volumetric strains with those of the deviatoric strains, on the basis of a parametric study. A few numerical examples are given to illustrate the hydro‐mechanical behaviour of the cavity and highlight the influence of key parameters (e.g. stiffness of backfill, lining deterioration rate, etc.). Further studies accounting for more general material behaviours for the backfill and external ground are ongoing. Copyright © 2008 John Wiley & Sons, Ltd.
Atmospheric‐pressure MOVPE growth of In‐rich InAlN
Authors: Houchin Y. , Hashimoto A. , Yamamoto A.
Published: April 2008

This paper reports the atmospheric‐pressure MOVPE growth of In‐rich InAlN. All InAlN films prepared here (Al content:0∼ 0.43) do not show phase separation. The incorporation of Al in InAlN is decreased with increasing growth temperature. A decrease in Al content is also observed for films grown at a position farther from the up‐stream end of the susceptor. The marked decrease in the Al content along the gas flow direction seems to be caused by the shortage of TMA supply at the downstream by the parasitic reaction of TMA. A single‐crystalline InAlN film with an Al content of 0‐0.43 is successfully grown by adjusting growth temperature and TMA/(TMI+TMA) molar ratio. FWHM of X‐ray rocking curve for InAlN is increased with increasing Al content. The carrier concentrations in InAlN films are comparable to that in InN (1‐5 × 1019 cm–3). All the single‐crystalline InAlN films with an Al content of 0‐0.3 show a photoluminescence at room temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Direct observation of uniform optical properties from microphotoluminescence mapping of InGaN quantum wells grown on slightly misoriented GaN substrates
Authors: Tachibana Koichi , Nago Hajime , Nunoue Shin‐ya
Published: April 2008

We have studied microphotoluminescence mapping of InGaN quantum wells grown on GaN (0001) substrates with misorientation toward [1$/bar 1$00] direction. The fluctuation of peak energy and full width at half maximum in the mapping was large when the misorientation angle was 0.0° or 0.1°, whereas it was small when the misorientation angle was over 0.2°. The average of the full width at half maximum of InGaN peak had the minimum of below60 meV at room temperature when the misorientation angle was around 0.28°. These results indicate that InGaN quantum wells have high crystalline quality when grown on GaN (0001) substrates with misorientation angle between 0.2° and 0.3° toward [1$/bar 1$00] direction. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence of cubic InN films on MgO (001) substrates
Authors: Inoue T. , Iwahashi Y. , Oishi S. , Orihara M. , Hijikata Y. , Yaguchi H. , Yoshida S.
Published: April 2008

We have studied photoluminescence from cubic InN films grown on MgO substrates with a cubic GaN underlayer by RF N2 plasma molecular beam epitaxy. A single PL peak was observed at 0.47 eV. By analyzing the reflectance spectra of cubic InN films, we could derive the refractive index and extinction coefficient, and found the band gap energy of cubic InN is 0.48 eV, indicating that the PL peak observed at 0.47 eV is due to the interband transition of cubic InN. The difference in the PL peak energy between hexagonal and cubic InN is in good agreement with that predicted by ab‐initio calculations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AlGaN‐based heterostructures grown on 4 inch Si(111) by MOVPE
Authors: Cheng Kai , Leys M. , Derluyn J. , Balachander K. , Degroote S. , Germain M. , Borghs G.
Published: April 2008

AlGaN is an important material for ultra‐violet light emitters, photo detectors and high breakdown voltage switching devices. In this work, crack‐free AlxGa1‐xN (5% < x < 55%) layers up to 1.5 μm have been grown on 4 inch Si(111) using an AlN/AlyGa1‐yN (y > 70%) template. The structural quality of AlGaN layers is comparable to that of GaN layers grown on silicon(111). For Al0.16Ga0.84N, the FWHM of HR‐XRD (0002) and (‐1102) ω‐scan is around 650 arc sec and 1200 arc sec respectively. Based on this high quality AlGaN buffer, a double heterostructure (DH) FET was demonstrated. The sheet resistance of DH‐FET is 274 ± 4.7 Ω/□ and the uniformity value of 1.7% is also excellent. Some of the wafers have been processed. Devices with a gate length of 2 μm showed current density of 500 mA/mm and transconductance of more than 200 mS/mm. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ozone and UV assisted oxidation of InN surfaces
Authors: Ecke G. , Wang Ch. Y. , Cimalla V. , Ambacher O.
Published: April 2008

High quality InN layers suffer from extremely high electron concentrations especially on surfaces and at interfaces. Even if their electron mobility could be extremely high, this prevents the electron depletion and so the application of this outstanding material in field effect transistors. Surface treatments like oxidation assisted by UV irradiation under Ozone atmosphere results in the decrease of the surface electron concentration. This has been confirmed by a combination of resistance and AES measurements. In order to investigate the surface modification by this oxidation laterally highly resolved Auger measurements have been carried out. The Auger signal intensities give information about the growing surface oxygen concentration whereas the Auger peak positions give information about the position of the Fermi level. The results show, that the oxidation process is heavily dependent on the quality of the InN surface. The oxidation is laterally inhomogeneous and the growing oxygen concentration is accompanied by a peak shift to the rhomboedric indium oxide value. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optically pumped lasing of GaN/AlGaN structures grown along a non‐polar crystallographic direction
Authors: Teisseyre H. , Szyman’︁ski M. , Khachapuridze A. , Świetlik T. , Skierbiszewski C. , Feduniewicz‐Żmuda A. , Siekacz M. , Łucznik B. , Kamler G. , Kryśko M. , Suski T. , Perlin P. , Grzegory I. , Porowski S.
Published: April 2008

Due to their undesirable spontaneous and piezoelectric polarizations, nitride structures grown along polar directions are subject to high built‐in electric fields. A promising means of overcoming the effects related to built‐in electric fields and, thereby, obtaining higher quantum efficiencies is to grow nitrides along a non‐polar direction. It is our intention to report our recent progress on non‐polar homo‐epitaxial structures grown by PAMBE along the (11$/bar 2$0) non‐polar direction. As a substrate we used GaN bulk crystals grown by the High Pressure Solution method and overgrown by HVPE. As has been previously reported, non‐polar AlGaN/GaN quantum wells possess sharp excitonic lines. We are able to present optically pumped laser action on separate confinement heterostructures. Laser action is clearly proved by spontaneous emission saturation, abrupt line narrowing, and the strong TE polarization of output light. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of oxygen plasma treatment on the tribological properties of Si‐DLC coatings
Authors: Choi J. , Nakao S. , Ikeyama M. , Kato T.
Published: April 2008

The cover picture of this issue of physica status solidi (c) has been taken from the article [1]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Robust design via simulation experiments: a modified dual response surface approach
Authors: Giovagnoli Alessandra , Romano Daniele
Published: April 2008

The existing procedures for robust design, devised for physical experiments, may be too limiting when the system can be simulated by a computer model. In this paper we introduce a modification of the dual response surface modelling, which incorporates the option of stochastically simulating some of the noise factors when their probabilistic behaviour is known. Our method generalizes both the crossed and the combined array approaches and finds a natural application to integrated parameter and tolerance design. The method appears suitable for designing complex measurement systems and in this paper is applied to the design of a high‐precision optical profilometer. Copyright © 2008 John Wiley & Sons, Ltd.
Characterization of resolution cycle times of corrective actions in mobile terminals
Authors: Mwegerano Anderson , Kytösaho Pekka , Liukkonen Timo , Tuominen Aulis
Published: April 2008

Resolution cycle times for resolving issues raised by customers is one of the essential factors for indication of the customer's satisfaction. The fact that there are many mobile terminals manufacturers implies that competition to grab and hold market share for a sustainable time is very strong. A forecasting model, based on a selected statistical distribution, is built up to give an estimation of the resolution time in three different category products. In this paper the model does not specify different failure symptoms reported by customers. Uncertainties and the reliability of the model buildup are discussed and example of an optimized correction action is given. Copyright © 2008 John Wiley & Sons, Ltd.
Classical and Hologram QSAR Studies on a Series of Inhibitors of Trypanosomatid Glyceraldehyde‐3‐Phosphate Dehydrogenase
Authors: Guido Rafael V. C. , Castilho Marcelo S. , Mota Sabrina G. R. , Oliva Glaucius , Andricopulo Adriano D.
Published: April 2008

Leishmaniasis and trypanosomiasis are major causes of morbidity and mortality in both tropical and subtropical regions of the world. The current available drugs are limited, ineffective, and require long treatment regimens. Due to the high dependence of trypanosomatids on glycolysis as a source of energy, some glycolytic enzymes have been identified as attractive targets for drug design. In the present work, classical Two‐Dimensional Quantitative Structure–Activity Relationships (2D QSAR) and Hologram QSAR (HQSAR) studies were performed on a series of adenosine derivatives as inhibitors of Leishmania mexicana Glyceraldehyde‐3‐Phosphate Dehydrogenase (LmGAPDH). Significant correlation coefficients (classical QSAR, r2=0.83 and q2=0.81; HQSAR, r2=0.91 and q2=0.86) were obtained for the 56 training set compounds, indicating the potential of the models for untested compounds. The models were then externally validated using a test set of 14 structurally related compounds and the predicted values were in good agreement with the experimental results (classical QSAR, $\rm{ r_{{\rm{pred}}}^2 = 0.94}$; HQSAR, $\rm{ r_{{\rm{pred}}}^2 = 0.92}$).
The complex formation of tetracyclohexylammonium C1‐resorcinarene with various guests – an electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry study
Authors: Mäkinen Marko , Kalenius Elina , Neitola Raisa , Rissanen Kari , Vainiotalo Pirjo
Published: April 2008

The complex formation of a tetraammonium C1‐resorcinarene (R+4HCl) was studied using electrospray ionization Fourier transform ion cyclotron resonance (ESI‐FTICR) mass spectrometry. Although R+4HCl easily loses its counter ions in the ESI process, a neutral self‐assembled structure with an intramolecular circular hydrogen‐bonded 16‐membered N+H ··· X− ··· HN+ array with ammonium ion as the charge‐giving species was observed in the gas phase. In addition to chloride, several other counter ions were also studied. The size and basicity of the counter ion as well as the size of the charge‐giving cation strongly affected the gas‐phase stability of the self‐assembled system. H/D exchange experiments showed that the ammonium substituents in the apical position of R affect the hydrogen‐bonding system in the resorcinarene. The complexation of the saturated dicarboxylic acids was found to depend on the length of the carbon chain. The rigidity of the molecular skeleton of the acid improved the complexation considerably. The orientation and position of the carboxylic groups also had an effect on the complexation and consequently enabled stereochemical differentiation of the acids. Mass spectrometric observations were supported by theoretical calculations. Copyright © 2008 John Wiley & Sons, Ltd.
Sample size determination for soft‐bottom sampling in large rivers and comparison with the chironomid pupal exuvial technique (CPET)
Authors: Raunio Janne , Anttila‐Huhtinen Marja
Published: April 2008

Our objective in this study was to determine the adequate sample size for the use of grab sampling in the biomonitoring of large soft‐bottom rivers. We also compared two sampling methods, grab sampling and the Chironomid Pupal Exuvial Technique (CPET), in detecting anthropogenic impacts in a large boreal river and assessed the degree of concordance between the two data sets. Sample size determination showed that, at the lowest possible taxonomic level, a minimum of eight benthic samples was required to obtain a reliable picture of benthic communities. When using the CPET, the number of chironomid species was nearly twice that of all benthic macroinvertebrates in the grab samples. In addition, a majority of the chironomid species found in the grab samples was also detected using the CPET. Although both data sets indicated significant differences in benthic communities between the sampling sites in the river Kymi, a Mantel test showed that patterns in community composition were not concordant. This was mainly because benthic samples from the deep depositional areas of the river indicated poorer ecological status than did the CPET data, which integrate species from various depths and habitats. Thus, samples from a single macrohabitat may not adequately represent environmental conditions of large rivers. Overall, our results suggest that the CPET provides a reliable and cost‐effective alternative, or a supplementary assessment tool, to more traditional sampling methods when assessing anthropogenic stresses in large boreal rivers. Copyright © 2008 John Wiley & Sons, Ltd.
A Histogram Matching Approach for assessment of flow regime alteration: application to environmental flow optimization
Authors: Shiau Jenq‐Tzong , Wu Fu‐Chun
Published: April 2008

In this paper we present a Histogram Matching Approach (HMA) for assessment of the flow regime alteration. The HMA uses the degree of histogram dissimilarity as a metric for impact assessment, which is based on the quadratic‐form distance between the frequency vectors of the pre‐ and post‐impact histograms weighted by a specified similarity matrix. The HMA is coupled with an aggregated multiobjective optimization genetic algorithm and applied to a case study on the Kaoping diversion weir (Taiwan) for determining the optimal environmental flow scheme that balances the ecosystem and human needs objectives. Two key issues are addressed in this study. First, we compare the performances of the HMA and existing Range of Variability Approach (RVA). Second, we employ three types of similarity function to investigate their effect on the outcomes of the HMA. The results reveal that the HMA consistently outperforms the RVA in preserving the natural flow variability regardless of what type of similarity function is used. No single type of similarity function can be found that would simultaneously best preserve the natural patterns of 32 Indicators of Hydrologic Alteration (IHA). For the situations where the water‐supply reliability is of critical concern, the pulse similarity is recommended because it would assure the smallest water‐supply deficit. If, however, minor degradation in the water‐supply reliability may be overlooked, the linear similarity is suggested because it would generally result in the post‐impact flows that most satisfactorily resemble to the natural flow regime. Copyright © 2008 John Wiley & Sons, Ltd.
Economic analysis of water temperature reduction practices in a large river floodplain: an exploratory study of the Willamette River, Oregon
Authors: Seedang Saichon , Fernald Alexander G. , Adams Richard M. , Landers Dixon H.
Published: April 2008

This paper examines ecosystem restoration practices that focus on water temperature reductions in the upper mainstem Willamette River, Oregon, for the benefit of endangered salmonids and other native cold‐water species. The analysis integrates hydrologic, natural science and economic models to determine the cost‐effectiveness of alternative water temperature reduction strategies. A temperature model is used to simulate the effects of combinations of upstream riparian shading and flow augmentations on downstream water temperatures. Costs associated with these strategies are estimated and consist of the opportunity costs of lost agricultural production and recreation opportunities due to flow releases from an up‐stream reservoir. Temperature reductions from another strategy, hyporheic flow enhancement, are also examined. Restoration strategies associated with enhanced hyporheic cooling consist of removal/reconnection of current obstacles to the creation of dynamic river channel complexity. The observed reduction of summer water temperatures associated with enhanced channel complexity indicates that restoring hyporheic flow processes is more likely to achieve cost‐effective temperature reductions and meet the total maximum daily load (TMDL) target than conventional approaches that rely on increased riparian shading or/and combinations of flow augmentation. Although the costs associated with the hyporheic flow enhancement approach are substantial, the effects of such a long‐term ecological improvement of the floodplain are expected to assist the recovery of salmonid populations and provide ancillary benefits to society. Copyright © 2008 John Wiley & Sons, Ltd.
Generalizing from clinical trial data: A case study. The risk of suicidality among pediatric antidepressant users
Authors: Greenhouse Joel B. , Kaizar Eloise E. , Kelleher Kelly , Seltman Howard , Gardner William
Published: April 2008

For the results of randomized controlled clinical trials (RCTs) and related meta‐analyses to be useful in practice, they must be relevant to a definable group of patients in a particular clinical setting. To the extent this is so, we say that the trial is generalizable or externally valid. Although concern about the generalizability of the results of RCTs is often discussed, there are few examples of methods for assessing the generalizability of clinical trial data. In this paper, we describe and illustrate an approach for making what we call generalizability judgments and illustrate the approach in the context of a case study of the risk of suicidality among pediatric antidepressant users. Copyright © 2008 John Wiley & Sons, Ltd.
Bayesian disease mapping using product partition models
Authors: Hegarty Avril , Barry Daniel
Published: April 2008

Our objective is to develop a model to estimate the relative risk of disease in each area, Ai, i=1, … , n, of a region and to identify areas of unusually high or low risk. We use a product partition model (PPM) in which we assume that the true relative risks can be partitioned into a number of components or sets of areas where the relative risks are equal. The PPM allows the data to weight those partitions likely to hold and inference about particular parameters may be made by first conditioning on the partition and then averaging over all partitions. We develop Markov chain Monte Carlo (MCMC) techniques to approximate the posterior distributions of the partitions and the parameters. We first test the method in a simulation study and then apply it to data for two separate groups of different types of cancer in the Mid‐Western Health Board region in Ireland. The results are compared with those obtained using the standardized mortality ratio method, an empirical Bayes method, a spatial scan method and a nonparametric Bayesian method. Copyright © 2008 John Wiley & Sons, Ltd.
Repeated events and total time on test
Authors: Kvist Kajsa , Andersen Per Kragh , Angst Jules , Kessing Lars Vedel
Published: April 2008

We adopt the total time on test procedure to investigate monotone time trends in the intensity in a repeated event setting. The correct model is assumed to be a proportional hazards model, with a random effect to account for dependence within subjects. The method offers a simple routine for testing relevant hypotheses for recurrent event processes, without making distributional assumptions about the frailty. Such assumptions may severely affect conclusions concerning regression coefficients and cause bias in the estimated heterogeneity. The method is illustrated by re‐analyzing Danish registry data and a long‐term Swiss clinical study on recurrence in affective disorder. Copyright © 2008 John Wiley & Sons, Ltd.
A unified modeling framework for metabonomic profile development and covariate selection for acute trauma subjects
Authors: Ghosh S. , Dey D. K.
Published: April 2008

Acute trauma is often associated with progressive deterioration of multiple organ systems in humans and is the leading cause of death in trauma care units. Identification of specific organ failure in a non‐invasive manner and the contribution of different demographic factors on the casual progression of acute trauma are of supreme interests for successful diagnosis, prognosis or monitoring of trauma status. Recently, electrospray ionization and matrix‐assisted laser desorption time‐of‐flight mass spectrometry have been used to identify biomarkers in both proteomics and metabonomics studies. Data sets generated from mass spectrometers in such studies are generally very large in size and thus require the use of sophisticated statistical techniques to glean useful information. In a recent development, Ghosh et al. (BMC Bioinformatics 2008; 9:38) suggested a unified semiparametric approach to distinguish urinary metabolic profiles in a group of traumatic subjects from those of a control group consisting of normal individuals. In this study we have extended their approach by combining available covariate information in the development of metabonomic profile of acute trauma. We have shown that age is a statistically significant covariate across trauma and control group, thus pointing out the fact that prognosis of trauma may be acutely linked with subjects' age. Copyright © 2008 John Wiley & Sons, Ltd.
Model replication: transformations to address model scalability
Authors: Lin Yuehua , Gray Jeff , Zhang Jing , Nordstrom Steve , Gokhale Aniruddha , Neema Sandeep , Gokhale Swapna
Published: April 2008

In model‐driven engineering, it is often desirable to evaluate different design alternatives as they relate to scalability issues of the modeled system. A typical approach to address scalability is model replication, which starts by creating base models that capture the key entities as model elements and their relationships as model connections. A collection of base models can be adorned with necessary information to characterize a specific scalability concern as it relates to how the base modeling elements are replicated and connected together. In current modeling practice, such a model replication is usually accomplished by scaling the base model manually. This is a time‐consuming process that represents a source of error, especially when there are deep interactions between model components. As an alternative to the manual process, this paper presents the idea of automated model replication through a model transformation process that expands the number of elements from the base model and makes the correct connections among the generated modeling elements. The paper motivates the need for model replication through case studies taken from models supporting different domains. Copyright © 2008 John Wiley & Sons, Ltd.
New adaptive compressors for natural language text
Authors: Brisaboa N. R. , Fariña A. , Navarro G. , Parama J. R.
Published: April 2008

Semistatic byte‐oriented word‐based compression codes have been shown to be an attractive alternative to compress natural language text databases, because of the combination of speed, effectiveness, and direct searchability they offer. In particular, our recently proposed family of dense compression codes has been shown to be superior to the more traditional byte‐oriented word‐based Huffman codes in most aspects. In this paper, we focus on the problem of transmitting texts among peers that do not share the vocabulary. This is the typical scenario for adaptive compression methods. We design adaptive variants of our semistatic dense codes, showing that they are much simpler and faster than dynamic Huffman codes and reach almost the same compression effectiveness. We show that our variants have a very compelling trade‐off between compression/decompression speed, compression ratio, and search speed compared with most of the state‐of‐the‐art general compressors. Copyright © 2008 John Wiley & Sons, Ltd.
Numerical study of fully developed turbulent flow within and above a dense forest
Authors: Dalpé Benoit , Masson Christian
Published: April 2008

Fully developed wind flow predictions within and above a dense forest were obtained using a computational fluid dynamics model. The model used a porous media analogy and a modified k‐ϵ turbulence model where source terms were added to the momentum and turbulence equations. The mathematical model was solved using the software FLUENT 6.2. Experimental measurements from a black spruce forest, a jack pine forest and an aspen forest were used to validate the model. Two different ground boundary conditions were proposed: a full‐slip boundary condition and a boundary condition that takes into account the forest ground roughness. Using these two boundary conditions, the accuracy of the proposed method was tested for forests with low foliage density. The innovative top boundary condition of Dalpé and Masson was validated with experimental measurements from Amiro. A sensitivity analysis was also performed on two important parameters: the drag coefficient and the leaf area density distribution. Results indicate that the proposed method simulated well the characteristics of wind flow within and above a forest. Results also indicate that, to obtain accurate results above the forest, it is necessary to take into account the forest ground roughness for forests with CDLAI < 0.6. Copyright © 2008 John Wiley & Sons, Ltd.
Provenance study of Gothic paintings from North‐East Slovakia by handheld x‐ray fluorescence, microscopy and x‐ray microdiffraction
Authors: Hradil David , Hradilová Janka , Bezdička Petr , Švarcová Silvie
Published: April 2008

During the restoration of the Altarpiece of Matejovce, Northern Slovakia, a unique example of the so‐called Cracow school of painting of European 15th century, noninvasive handheld x‐ray fluorescence was used for in situ measurements in restoration probes with the aim to distinguish original paints and repaints. The layer stratigraphy was then precisely described on cross‐sections of microsamples by light and electron microscopes. Material composition of original Gothic layers was also investigated by powder x‐ray microdiffraction and compared with materials used on different parts of the Altarpiece of Bardejov, North‐East Slovakia, and on the unique canvas painting ‘The death of St. Acacius and Ten Thousands Martyrs of Mt. Ararat’ devoted by some historians to the same workshop. We found that Altarpiece of Matejovce was partially repainted maybe in 18th and namely in 19th centuries with no important influence to the original artistic composition of figures. We confirmed that only two triangular gables from the Altarpiece of Bardejov can be assigned to the workshop of the Master of Matejovce altarpiece. In the case of canvas painting, its belonging to the same workshop was definitely approved by this materials research. The most important feature was that Master of Matejovce altarpiece used Zn‐dolomites containing iron red, which could come from oxidation zones of carbonate‐hosted ZnPb deposits near Cracow, Poland, and azurite with admixtures of Cu and Zn arsenates possibly from the Slovak Cu deposit at L'ubietová. The preference of regional sources of pigments distinguishes the ‘Cracow school’ from other workshops acting simultaneously in the same region. Copyright © 2008 John Wiley & Sons, Ltd.
Valproic acid metabolism and its effects on mitochondrial fatty acid oxidation: A review
Authors: Silva M. F. B. , Aires C. C. P. , Luis P. B. M. , Ruiter J. P. N. , IJlst L. , Duran M. , Wanders R. J. A. , Tavares de Almeida I.
Published: April 2008

Valproic acid (VPA; 2‐n‐propylpentanoic acid) is widely used as a major drug in the treatment of epilepsy and in the control of several types of seizures. Being a simple fatty acid, VPA is a substrate for the fatty acid β‐oxidation (FAO) pathway, which takes place primarily in mitochondria. The toxicity of valproate has long been considered to be due primarily to its interference with mitochondrial β‐oxidation. The metabolism of the drug, its effects on enzymes of FAO and their cofactors such as CoA and/or carnitine will be reviewed. The cumulative consequences of VPA therapy in inborn errors of metabolism (IEMs) and the importance of recognizing an underlying IEM in cases of VPA‐induced steatosis and acute liver toxicity are two different concepts that will be emphasized.
Effects of long‐term grazing on the morphological and functional traits of Leymus chinensis in the semiarid grassland of Inner Mongolia, China
Authors: Zhao Wei , Chen Shi‐Ping , Han Xing‐Guo , Lin Guang‐Hui
Published: April 2008

Livestock grazing represents a major human disturbance to grasslands throughout the world. We evaluated the effects of long‐term grazing (>20 years) on a dominant perennial grass species, Leymus chinensis (Trin.) Tzvel., in the semiarid grassland of Inner Mongolia, China, in terms of its morphological and functional responses. L. chinensis, one of the most abundant species in semiarid grassland, had significantly smaller leaf area, fewer vegetative tillers and shorter shoot internodes length, but significantly greater specific leaf area for the individuals in the grazing plot than those in the exclosure (grazing‐free) plot. Long‐term grazing also altered the relative distribution of biomass to leaves, roots and rhizomes. The biomass, coverage and the number of species were lower in the grazing plot by 50–70% in comparison with those in the grazing‐free plot. In addition, the long‐term grazing substantively decreased the physiological capacities of this grass species, including significantly lower net photosynthetic rate, apparent quantum efficiency, photochemical efficiency of PSII and water use efficiency. Significantly higher stable oxygen isotope ratios (δ18O) of the soil water in the grazing plot than those in the grazing‐free plot indicated a much higher soil evaporation in the grazing plot because of less litter coverage. Seasonal patterns in the δ18O values of the stem water of L. chinensis and three other common species in the grazing and grazing‐free plots indicated that plants in the grazing and grazing‐free plots might shift their water sources differently from a dry month (June) to a wet month (August). This study illustrated the importance of using different approaches to study the possible responses of grass species in arid regions to human disturbances, such as long‐term grazing.
Intraoperative Electrophysiological Studies to Predict the Efficacy of Neurolysis After Nerve Injury—Experiment in Rats
Authors: Yan Ji-Geng , Eldridge Mary P. , Dzwierzynski William W. , Sanger James R. , Matloub Hani S. , Yan Yu Hui , Zhang Lin-Ling , Jaradeh Safwan
Published: April 2008

Compound muscle action potentials (CMAPs) can be used to analyze injury and recovery of nerve. This standardized study evaluates the value of CMAP analysis in predicting the long-term efficacy of neurolysis. CMAP amplitude is also used to determine the optimal extent of neurolysis. The left peroneal nerves of 30 rats were crushed. CMAPs were recorded for both crushed (left) and control (right) nerves. Fifteen rats underwent neurolysis 3 months post crush injury; the remaining 15 were sham controls and did not undergo neurolysis. CMAP measurements were taken after: (1) release of the nerve from the fascia, (2) opening the epineurium, and (3) opening the perineurium. At 3 months post crush injury, opening the epineurium resulted in a statistically significant increase in CMAP. CMAP increase with perineurial neurolysis was greater than with fascial release of the nerve but was not statistically different from that of epineurial release. At 5 months post crush injury, recovery of crushed nerves that underwent neurolysis was 90% and significantly less at 70.5% in rats not treated with neurolysis, according to CMAP analysis. Two conclusions can be made from this study. First, intraoperative neurophysiologic studies can monitor the immediate results of neurolysis and predict long-term results in the injured nerve. Second, epineurotomy is important in neurolysis, improves the function of the nerve, less invasive, and a slightly more effective technique than perineurotomy.
Lipid Classes, Fatty Acid Distributions and Triacylglycerol Molecular Species of Broad Beans (Vicia faba)
Authors: Yoshida Hiromi , Tomiyama Yuka , Yoshida Naoko , Saiki Masayuki , Mizushina Yoshiyuki
Published: April 2008

Seed oils from four legume cultivars of Vicia faba, grown in Japan, were extracted and classified by thin‐layer chromatography (TLC) into eight fractions. The major lipid components were triacylglycerols (TAG: 48.8–50.1%) and phospholipids (PL: 47.5–50.5%), while hydrocarbons (HC), steryl esters (SE), free fatty acids (FFA), diacylglycerols (1,3‐ and 1,2‐DAG) and monoacylglycerols (MAG) were present in minor proportions (1.8–2.4%). All lipid samples had high amounts of total unsaturated FA, representing 79.7–82.8% and 77.6–79.7% for TAG and PL, respectively. Molecular species and FA distributions of TAG, isolated from the total lipids in the broad beans, were analyzed by a combination of argentation‐TLC and GC. Fourteen different molecular species were detected. With a few exceptions, the main TAG components were S2D (6.1–8.9%), SD2 (7.8–10.5%), SMT (6.3–8.5%), M2D (4.5–6.2%), MD2 (18.9–21.8%), D3 (21.0–23.9%) and MDT (8.1–10.2%) (where S, M, D, and T denote a saturated fatty acid, a monoene, a diene, and a triene, respectively). These results suggest that the lipid classes, FA distributions and TAG molecular species of broad beans are not dependent on the cultivation areas during the growing season.
The use of the Taylor spatial frame in adolescent Blount's disease: Is fibular osteotomy necessary?
Authors: Eidelman Mark , Bialik Viktor , Katzman Alexander
Published: April 2008

Background

The standard treatment of adolescent Blount disease includes proximal tibial osteotomy and osteotomy of the fibula. Some believe that the fibula should also be fixed to prevent migration and subluxation. The purpose of the current study was to examine the results of treatment of patients with adolescent tibia vara treated by tibial osteotomy and Taylor spatial frame (TSF) without fibular osteotomy.

Methods

Correction of deformities was performed on eight patients (ten tibias) with adolescent Blount disease using TSF. The fibula was not osteotomized in any patient and was not fixed in the last five patients.

Results

All patients had precise anatomical correction of deformities and no problems related to the fibula occurred during or after correction.

Conclusion

Based on our experience we believe that placement of the origin at the level of the proximal tibial fibular joint in conjunction with external fixation eliminates the need for fibular osteotomy and the potential morbidity of this procedure in patients with mild to moderate tibia vara.
Protein arginine (N)‐methyl transferase 7 (PRMT7) as a potential target for the sensitization of tumor cells to camptothecins
Authors: Verbiest Vincent , Montaudon Danièle , Tautu Michel T. , Moukarzel Joyce , Portail Jean-Pierre , Markovits Judith , Robert Jacques , Ichas François , Pourquier Philippe
Published: April 2008

PRMT7 belongs to the protein arginine methyl‐transferases family. We show that downregulation of PRMT7α and β isoforms in DC‐3F hamster cells was associated with increased sensitivity to the Top1 inhibitor camptothecin (CPT). This effect was not due to a change in Top1 contents or catalytic activity, or to a difference in the reversal of DNA breaks. Overexpression of PRMT7α and β in DC‐3F cells had no effect on CPT sensitivity, whereas it conferred a resistance to DC‐3F/9‐OH‐E cells for which both isoforms are reduced by two‐ to three‐fold as compared to DC‐3F parental cells. Finally, downregulation of the human PRMT7 could also sensitize HeLa cells to CPT, suggesting that it could be used as a target to potentiate CPT derivatives.