bluuebunny/crossref_metadata_2025 huggingface dataset:
Silicate layer exfoliation in polyolefin/clay nanocomposites based on maleic anhydride modified polyolefins and organophilic clay
Authors: Hasegawa Naoki , Usuki Arimitsu
Published: April 2004

Silicate layer exfoliation processes in maleic anhydride (MA) modified polyolefins were studied by using X‐ray diffraction measurements, scanning electron microscopy, and transmission electron microscopy observations. Modified polyolefins grafted with 0.09–4.5 wt % MA groups intercalate into the organophilic clay galleries modified with stearyl ammonium ions. Molten MA‐modified polypropylene continuously intercalates into the galleries and the silicate layers exfoliate spontaneously without shear. However, the silicate layers maintain arranging parallel together, although the interlayer spacing expands over 10 nm. By adding shear, the silicate layers homogeneously disperse into MA‐modified polypropylene matrix. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 464–470, 2004
Enantioselective Fluorescence Sensing of Amino Acids by Modified Cyclodextrins: Role of the Cavity and Sensing Mechanism
Authors: Pagliari Sara , Corradini Roberto , Galaverna Gianni , Sforza Stefano , Dossena Arnaldo , Montalti Marco , Prodi Luca , Zaccheroni Nelsi , Marchelli Rosangela
Published: April 2004

Two selectors based on modified cyclodextrins containing a metal binding site and a dansyl fluorophore—6‐deoxy‐6‐N‐(Nα‐[(5‐dimethylamino‐1‐naphthalenesulfonyl)aminoethyl]phenylalanylamino‐β‐cyclodextrin—containing D‐Phe (3) and L‐Phe (4) moieties were synthesized. The conformations of the two selectors were studied by circular dichroism, two‐dimensional NMR spectroscopy and time‐resolved fluorescence spectroscopy. Cyclodextrin 4 was found to have a predominant conformation in which the dansyl group is self‐included in the cyclodextrin cavity, while 3 showed a larger proportion of the conformation with the dansyl group outside the cavity. As a consequence, the two cyclodextrins were found to bind copper(II) with different affinities, as revealed by fluorescence quenching in competitive binding measurements. Addition of D‐ or L‐amino acids induced increases in fluorescence intensity, which were dependent on the amino acid used and in some cases on its absolute configuration. The cyclodextrin 4 was found to be more enantioselective than 3, suggesting that the self‐inclusion in the cyclodextrin cavity strongly increases the chiral discrimination ability of the copper(II) complex. Accordingly, a linear fluorescent ligand Nα‐[(5‐dimethylamino‐1‐naphthalenesulfonyl)aminoethyl]‐N1‐propyl‐phenylalaninamide, which has the same binding site and absolute configuration as 4, showed very low chiral discrimination ability. The enantioselectivity in fluorescence response was found to be due to the formation of diastereomeric ternary complexes, which were detected by ESI‐MS and by circular dichroism. Time‐resolved fluorescence studies showed that the fluorescence of the dansyl group was completely quenched in the ternary complexes formed, and that the residual fluorescence was due to uncomplexed ligand.
Total Synthesis and Biological Evaluation of the Protein Phosphatase 2A Inhibitor Cytostatin and Analogues
Authors: Bialy Laurent , Waldmann Herbert
Published: April 2004

The total synthesis of the natural product cytostatin is described which inhibits protein phosphatase 2A. Cytostatin has anti‐metastatic properties and induces apoptosis. On the basis of this synthesis the relative and absolute configuration of cytostatin could be assigned. Key structural elements of cytostatin are an α,β‐unsaturated lactone group and a side chain embodying a phosphate and a rather unstable (Z,Z,E)‐triene subunit. In addition, the natural product carries six stereocenters. For the construction of the stereocenters reagent‐controlled transformations were used in order to ensure maximum stereochemical flexibility. The Evans syn‐aldol reaction was chosen to establish the stereochemistry at C‐4, C‐5, C‐9 and C‐10; C‐6 was introduced by means of the Evans asymmetric alkylation. In all cases the same chiral auxiliary was employed as stereodirecting group. The stereocenter at C‐11 was established by an asymmetric reduction using CBS‐oxazaborolidine. Temporary protection of the phosphate group was achieved best by using the base‐labile 9‐fluorenylmethyl group, which could be cleanly cleaved by an excess of triethylamine; this reaction yielded analytically pure phosphates after a simple aqueous work‐up. The (Z,Z,E)‐triene embodied in cytostatin was synthesized by means of a Stille coupling as key transformation. The synthesis sequence established in this way readily gave access to a series of analogues with simplified structure. Initial biological testing of these analogues proved that the α,β‐unsaturated lactone, the C‐11‐hydroxy group and a fully deprotected phosphate moiety at C‐9 are essential for the PP2A‐inhibitory activity of cytostatin. The rather unstable triene moiety in the side chain can be replaced by other lipophilic residues with only moderate decrease of biological activity. Other phosphatases, that is, PP1, VHR, PTP1B, CD45, were not inhibited by cytostatin or any of the analogues, demonstrating the high selectivity of this compound. These findings will be useful for the design and synthesis of cytostatin‐derived chemical tools for the study of biological processes influenced by PP2A.
Reaction of a Terminal Phosphinidene Complex with Azulenes: η1‐Complexes, CH Bond Insertions, and 1,4‐Adducts
Authors: Bulo Rosa E. , Ehlers Andreas W. , de Kanter Frans J. J. , Schakel Marius , Lutz Martin , Spek Anthony L. , Lammertsma Koop , Wang Bing
Published: April 2004

Reaction of an in situ generated phosphinidene complex [PhPW(CO)5] with the aromatic azulene and guaiazulene leads to unexpected 1,4‐adducts of the seven‐membered ring and to CH bond insertion of the five‐membered ring. A DFT analysis suggests that the reaction is initiated by formation of a η1‐complex between the phosphinidene and the five‐membered ring of the aromatic substrate. Four conformations of this complex were identified. Two convert without barrier to the slightly more stable syn‐ and anti‐1,2‐adducts. These undergo pericyclic 1,7‐sigmatropic rearrangements with remarkably low barriers to give 1,4‐adducts, with an inverted configuration at the phosphorus center. An X‐ray crystal structure is presented for one of the 1,4‐adducts of guaiazulene. The other two η1‐complexes insert with modest barriers into a CH bond of the five‐membered ring.
Stability of small‐amplitude shock profiles of symmetric hyperbolic‐parabolic systems
Authors: Mascia C. , Zumbrun K.
Published: April 2004

Combining pointwise Green's function bounds obtained in a companion paper [36] with earlier, spectral stability results obtained in [16], we establish nonlinear orbital stability of small‐amplitude Lax‐type viscous shock profiles for the class of dissipative symmetric hyperbolic‐parabolic systems identified by Kawashima [20], notably including compressible Navier‐Stokes equations and the equations of magnetohydrodynamics, obtaining sharp rates of decay in Lp with respect to small L1 ∩ H3 perturbations, 2 ≤ p ≤ ∞. Our analysis extends and somewhat refines the approach introduced in [35] to treat stability of relaxation profiles. © 2004 Wiley Periodicals, Inc.
Chromium(III) Ion Selective Electrode Based on Oxalic Acid Bis(Cyclohexylidene Hydrazide)
Authors: Gholivand Mohammad Bagher , Raheedayat Firozeh
Published: April 2004

A poly(vinyl chloride) membrane sensor based on oxalic acid bis (cyclohexylidene hydrazide) as membrane carrier was prepared and investigated as a Cr(III)‐selective electrode. The electrode reveals a Nernstian behavior (slope 19.8±0.4 mV decade−1) over a wide Cr(III) ion concentration range 1.0×10−7–1.0×10−2 mol dm−3 with a very low limit of detection (i.e., down to 6.3×10−8 mol dm−3). The potentiometric response of the sensor is independent of the pH of the test solution in the pH range 1.7–6.5. The electrode possesses advantage of very fast response, relatively long lifetime and especially good selectivity to wide variety of other cations. The sensor was used as an indicator electrode, in the potentiometric titration of chromium ion and in the determination of Cr(III) in waste water and alloy samples.
[Cu(L)](NO3)2 (L=4,7‐Bis(3‐aminopropyl)‐1‐thia‐4,7‐diazacyclononane) as a Suitable Ionophore for Construction of Thiocyanate‐Selective Electrodes and Their Use in Determination of Urinary and Salivary Thiocyanate Concentration
Authors: Shamsipur Mojtaba , Poursaberi Tahereh , Rezapour Morteza , Ganjali Mohammad Reza , Mousavi Mir Fazlollah , Lippolis Vito , Montesu Danilea Rita
Published: April 2004

The construction, performance characteristics, and application of polymeric membrane (PME) and coated graphite (CGE) thiocyanate‐selective electrodes are reported. The electrodes were prepared by incorporating the complex [Cu(L)](NO3)2 (L=4,7‐bis(3‐aminopropyl)‐1‐thia‐4,7‐diazacyclononane) into a plasiticized poly(vinyl chloride) membrane. The influence of membrane composition, pH of test solution, and foreign ions were investigated. The electrodes reveal Nernstian behavior over a wide SCN− ion concentration range (1.0×10−6–1.0×10−1 M for PME and 5.0×10−7–1.0×10−2 M for CGE) and show fast dynamic response times of 15 s and lower. The proposed sensors show high selectivity towards thiocyanate over several common organic and inorganic anions. They were successfully applied to the direct determination of thiocyanate in urine and saliva of smokers and nonsmokers, and as an indicator electrode in titration of Ag+ ions with thiocyanate.
Miniaturized Reference Electrodes. II. Use in Corrosive, Biological, and Organic Media
Authors: Ciobanu Madalina , Wilburn Jeremy P. , Lowy Daniel A.
Published: April 2004

In a recent paper [9] we reported the manufacturing and performance of miniaturized reference electrodes (MREs) with low sensitivity to chloride ions and pH. Here, we demonstrate the wide range applicability of a MRE based on an Ag/Ag2S internal reference element (IRE), imbedded in a photopolymerized hydrogel of improved composition, which contains the supporting electrolyte. Exchange current density, temperature coefficient, impedance value, and the voltammetric and potentiometric use of the Ag/Ag2S‐based MRE are discussed relative to the previously reported Ag/AgSCN, Ag/Ag3PO4, and Ag/AgCl‐based MREs. No special or extensive conditioning is required when moving these MREs from aqueous supporting electrolyte to an organic solution or from one organic medium to another, and the equilibration time in a new medium is very rapid (<6 min). The new Ag/Ag2S MRE has a highly stable potential in various media, including aqueous solutions (salt buffers and 20 wt.% H2SO4), biological samples (bovine serum albumin), mixed aqueous‐organic, and organic supporting electrolytes (methanol, ethanol, acetonitrile, propylene carbonate, methylene chloride, and DMSO). This is particularly advantageous when in the course of the electrochemical analysis an organic solution is being added to an aqueous supporting electrolyte. Such MREs are suitable for analyses of μL sample volumes and for use in protein‐containing media.
Wavelet Derivative: Application in Multicomponent Analysis of Electrochemical Signals
Authors: Zhang Xiuqi , Jin Jiye
Published: April 2004

The wavelet derivative was developed for resolving overlapped signals in electrochemical analysis. It has been shown that the wavelet derivative could be used as an effective tool in resolution enhancement of the electrochemical signals. Since signal‐to‐noise ratio (SNR) does not degrade significantly at high order derivatives, the wavelet derivative is much better than the conventional numerical derivative in resolving practical signals with low SNR, particularly in the case when the overlapped degree of complex is high and high order derivatives are required for the further resolution enhancement. In this article, applications of the wavelet derivative in the voltammetric determination of small mounts of substances in the presence of large mounts of potentially interfering species are presented, and the advantages of this technique are discussed as well.
Simultaneous Determination of Dopamine and Ascorbic Acid at an In‐Site Functionalized Self‐Assembled Monolayer on Gold Electrode
Authors: Zhang Lei , Jia Jianbo , Zou Xiangqin , Dong Shaojun
Published: April 2004

The in‐site functionalization of 4‐aminothiophenol (4‐ATP) self‐assembled monolayer on gold electrode at physiological pH yields a redox active monolayer of 4′‐mercapto‐N‐phenylquinone diimine (MNPD). The functionalized electrode exhibits excellent electrocatalytic responses towards dopamine (DA) and ascorbic acid (AA), reducing the overpotentials by about 0.22 V and 0.34 V, respectively, with greatly enhanced current responses. Due to its different catalytic activities toward DA and AA, the modified electrode resolves the overlapping voltammetric responses of DA and AA into two well‐defined voltammetric peaks by differential pulse voltammetry (DPV), which can be used for the simultaneous determination of these species in a mixture. The catalytic peak current obtained from DPV was linearly related to DA and AA concentration in the ranges of 5.0×10−6−1.25×10−4 M and 8.0×10−6−1.3×10−4 M with correlation coefficient of 0.999 and 0.998, respectively. The detective limits (3σ) for DA and AA were found to be 1.2×10−6 M and 2.4×10−6 M, respectively. The modified electrode shows good sensitivity, selectivity and stability, and has been applied to the determination of DA and AA simultaneously in samples with satisfactory results.
Behavior of moment‐resisting frame structures subjected to near‐fault ground motions
Authors: Alavi Babak , Krawinkler Helmut
Published: April 2004

Near‐fault ground motions impose large demands on structures compared to ‘ordinary’ ground motions. Recordings suggest that near‐fault ground motions with ‘forward’ directivity are characterized by a large pulse, which is mostly orientated perpendicular to the fault. This study is intended to provide quantitative knowledge on important response characteristics of elastic and inelastic frame structures subjected to near‐fault ground motions. Generic frame models are used to represent MDOF structures. Near‐fault ground motions are represented by equivalent pulses, which have a comparable effect on structural response, but whose characteristics are defined by a small number of parameters. The results demonstrate that structures with a period longer than the pulse period respond very differently from structures with a shorter period. For the former, early yielding occurs in higher stories but the high ductility demands migrate to the bottom stories as the ground motion becomes more severe. For the latter, the maximum demand always occurs in the bottom stories. Preliminary regression equations are proposed that relate the parameters of the equivalent pulse to magnitude and distance. The equivalent pulse concept is used to estimate the base shear strength required to limit story ductility demands to specific target values. Copyright © 2004 John Wiley & Sons, Ltd.
Seismic structural control using an electric servomotor active mass driver system
Authors: Lee Chien‐Liang , Wang Yen‐Po
Published: April 2004

This study investigates an electric‐type active mass driver (AMD) system for structural vibration control. Composed primarily of an electric servomotor and a ball screw, the electrical AMD system is free from noise problems, oil leakage, and labor‐intensive maintenance that commonly are associated with hydraulic AMD systems. The desired stroke amplification of the mass and the power demand of the servomotor can be adjusted via the ball screw pitch, which in turn affects the effectiveness and efficiency of the system. Meanwhile, an instantaneous optimal direct output feedback control algorithm is adopted. Numerical simulation is performed using a five‐story steel frame as the object structure under the conditions of the 1940 El Centro earthquake. The AMD system proves to be effective and efficient within a certain range of the ball screw pitch. The reductions of the peak responses can reach as high as 70% if properly designed. Requiring only the velocity measurement of the top floor for on‐line feedback control, the proposed control algorithm is recommended for practical implementation. Copyright © 2004 John Wiley & Sons, Ltd.
Damage evaluation models of reinforced concrete buildings based on the damage statistics and simulated strong motions during the 1995 Hyogo‐ken Nanbu earthquake
Authors: Nagato Kenichiro , Kawase Hiroshi
Published: April 2004

We have tried to estimate the yield shear strengths of reinforced concrete (RC) buildings based on the damage statistics in Kobe surveyed after the Hyogo‐ken Nanbu, Japan, earthquake of 1995 and the non‐linear response analyses for synthetic waveforms calculated from a complex seismic source and a three‐dimensional basin structure. First, a set of building models that represented the RC building stock in Kobe was constructed and plausible non‐linear multi‐degree‐of‐freedom models with four different numbers of stories were created based on the current seismic code and construction practice. For response analysis the damage criterion and the strength distribution should be assumed a priori. When the damage ratios for these standard models were calculated it was found that the damage ratios were so high that we had to increase the average yield strengths in order to match the calculated damage ratios to those observed. After searching the best models it was found that the estimated average yield strengths should be much higher than those based on the code, especially for low‐rise buildings. Using this set of building models we succeeded in reproducing the belt‐shaped area with high damage ratios in Kobe. One can apply the proposed methodology to different countries if there is enough damage data, strong motion records, and building statistics. If there is sparse damage data at several locations only, then our models can be adjusted to reproduce observed damage data and used for damage prediction as a first‐order approximation. Copyright © 2004 John Wiley & Sons, Ltd.
Blood T‐cell Vβ transcriptome in melanoma patients
Authors: Degauque Nicolas , Schadendorf Dirk , Brouard Sophie , Guillet Marina , Sébille Fabien , Höhn Hanni , Pallier Annaïck , Ruiz Catherine , Dupont Alexandre , Chapin Stéphane , Hofmann Udo , Maeurer Markus , Soulillou Jean‐Paul
Published: April 2004

Tumor‐cells have been shown to elicit MHC‐restricted and antigen‐specific T‐cell responses. In this article, we used a new approach to study T‐cell responses in tumor‐bearing patients based on a global representation of the Vβ‐transcriptome, making it possible to grade CDR3‐length distribution (CDR3‐LD) alterations. Six patients with advanced melanoma disease, from whom blood samples were taken before and serially after tyrosinase‐A peptide vaccination, were studied. The PBMC from patients displayed highly significant Vβ transcriptome alterations as compared to healthy individuals. Similar Vβ alterations could be detected both in PBMCs and at the tumor site. After vaccination, Vβ alterations could also be observed by gauging individually their transcript level but not their cell‐surface expression. Some Vβ families exhibited high Vβ/HPRT transcript ratios (e.g., Vβ1), which represented up to 44% of the whole transcriptome, a situation that was not reflected by an increase in the percentage of T cells that expressed the corresponding protein and was not observed in normal individuals. In several instances, CDR3‐LD altered T cells exhibited MHC‐restricted and tumor‐specific IFNγ or GM‐CSF production. Finally, we show that the presence of a tumor and probably vaccination can affect Vβ transcriptome patterns and induce specific clones reactive to autologous tumor or vaccinating peptides. In combination with other methods, such an approach should help in identifying the clones actually involved in the response against the tumor. © 2004 Wiley‐Liss, Inc.
BRCA1 mutations in South African breast and/or ovarian cancer families: Evidence of a novel founder mutation in Afrikaner families
Authors: Reeves Michelle D. , Yawitch Tali M. , van der Merwe Nerina C. , van den Berg Hester J. , Dreyer Greta , van Rensburg Elizabeth J.
Published: April 2004

Germ‐line mutations within BRCA1 are responsible for different proportions of inherited susceptibility to breast/ovarian cancer, and the spectrum of mutations within this gene is often unique to certain populations. At this time, there have been no reports regarding the role of BRCA1 in South African breast and/or ovarian cancer families. We therefore screened 90 South African breast/ovarian cancer families for BRCA1 mutations by means of PCR‐based mutation detection assays. Eighteen families (20%) were identified with BRCA1 disease‐causing mutations. Four Ashkenazi Jewish families were identified with the 185delAG mutation, whereas 2 Afrikaner and 1 Ashkenazi Jewish family were found to harbor the 5382insC mutation. Five of the families (5.56%), all of whom are Afrikaners, were found to carry the novel E881X mutation. Genotype analyses show that these patients share a common ancestor. Genealogic studies have identified 3 possible founding couples for this mutation, all of whom arrived in the Cape from France in the late 1600s. Of the remaining mutations detected, 3 have not been reported previously and include the S451X, 1493delC (detected twice) and 4957insC mutations. © 2004 Wiley‐Liss, Inc.
Optimal monetary rules and internationalized production
Authors: Cavallari Lilia
Published: April 2004

This paper explores the implications of international location of production for the optimal design of monetary policy in a framework that allows for price discrimination across international markets. By introducing multinational production in a dynamic open economy, the paper shows that optimal monetary rules do not react to foreign cyclical conditions. The paper further shows that non‐cooperative monetary rules cannot restore the flexible price allocation while international monetary cooperation can do so. Copyright © 2004 John Wiley & Sons, Ltd.
Political support for anti‐inflationary monetary policy
Authors: Di Gioacchino Debora , Ginebri Sergio , Sabani Laura
Published: April 2004

We model a two‐party representative democracy with citizen‐candidate in which the leader is elected while the central‐banker is appointed by the leader. Assuming that fiscal policy is ‘more important’ than monetary policy, we show that, if some individuals who dislike inflation get organized in a lobby and offer campaign contribution to the party that proposes a zero‐inflation policy, then even if the majority of the population, as well as the majority of party‐members, favour inflation, no inflation results in equilibrium. The paper provides a political economy explanation of the role played by financial interest groups in providing political support to anti‐inflationary monetary policy. Copyright © 2004 John Wiley & Sons, Ltd.
Endothelial cell functions in vitro cultured on poly(L‐lactic acid) membranes modified with different methods
Authors: Zhu Yabin , Gao Changyou , Liu Yunxiao , Shen Jiacong
Published: April 2004

We recently developed several methods to enhance the cell‐polymer interactions. Optimal conditions for each method have been revealed separately by in vitro cell culture. As a practical consideration for construction of tissue‐engineered organs, it is necessary to consider which is the most suitable and convenient in clinical applications. To compare the efficiency of these methods with respect to cell functions, poly‐L‐lactic acid (PLLA) was selected as matrix being modified by 1) aminolysis (PLLA‐NH2), 2) collagen immobilization with GA (PLLA‐GA‐Col), 3) chondroitin sulfate (CS)/collagen layer‐by‐layer (LBL) assembly (PLLA‐CS/Col), 4) photo‐induced grafting copolymerization of hydrophilic methacrylic acid (MAA) (PLLA‐g‐PMAA), and 5) further immobilization of collagen with 1‐ethyl‐3‐(3‐dimethylamino propyl) carbodiimide hydrochloride (EDAC) (PLLA‐g‐PMAA‐Col). The surface wettability of the modified PLLA was determined by water contact angle measurements. The cell response to the modified PLLA was quantitatively assessed and compared by using human umbilical endothelial cells (HUVECs) culture. Our results indicate that all the modifications can improve the cytocompatibility of PLLA (e.g., cells can attach with spreading morphology, proliferate and secret vWF and 6‐keto‐PGF1α). All the collagen‐modified PLLA showed more positive cell response than those purely aminolyzed or PMAA grafted. Among all the methods, collagen immobilization by LBL assembly or GA bridging after aminolysis is more acceptable for the convenience and applicability to scaffolds. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 436–443, 2004
Focused beam reflectance technique for in situ particle sizing in wastewater treatment settling tanks
Authors: De Clercq Bob , Lant Paul A , Vanrolleghem Peter A
Published: April 2004

Due to the complexities involved with measuring activated sludge floc size distributions, this parameter has largely been ignored by wastewater researchers and practitioners. One of the major reasons has been that instruments able to measure particle size distributions were complex, expensive and only provided off‐line measurements. The Focused Beam Reflectance Method (FBRM) is one of the rare techniques able to measure the particle size distribution in situ. This paper introduces the technique for monitoring wastewater treatment systems and compares its performance with other sizing techniques. The issue of the optimal focal point is discussed, and similar conclusions as found in the literature for other particulate systems are drawn. The study also demonstrates the capabilities of the FBRM in evaluating the performance of settling tanks. Interestingly, the floc size distributions did not vary with position inside the settling tank flocculator. This was an unexpected finding, and seriously questioned the need for a flocculator in the settling tank. It is conjectured that the invariable size distributions were caused by the unique combination of high solids concentration, low shear and zeolite dosing. Copyright © 2004 Society of Chemical Industry
Use of microemulsions for removal of color and dyes from textile wastewater
Authors: de Castro Dantas Tereza Neuma , Beltrame Leocadia Terezinha Cordeiro , Neto Afonso Avelino Dantas , de Alencar Moura Maria Carlenise Paiva
Published: April 2004

One of the major environmental problems in the textile dyeing industry is the removal of color from effluents. The present study deals with color removal from effluents using microemulsions. The wastewater used in this study was the reactive exhausted dye liquor from a dyeing house containing Procion Yellow H‐E4R (CI Reactive Yellow 84), Procion Blue H‐ERD (CI Reactive Blue 160) and Procion Red H‐E3B (CI Reactive Red 120). Color removal was determined by CIE L*a*b* (CIELAB) color space, CIE L*a*b* color difference, ΔE*ab, and absorbance. Color removal greater than 95% was achieved, attaining values lower than the consent requirements established by the Environmental Agency. It was observed that pH is an important parameter in color removal and effluent pH correction from 10.44 to 9 before extraction improved results. The results obtained were modeled using the Scheffé net method and evaluated through the construction of isoresponse diagrams by correlation graphics between experimental values and those obtained through use of model equations, providing an experimental error of less than 2%. The optimized method very efficiently removed all dyes contained in the effluent. The same microemulsion phase recovered after the extraction process can be used at least a further 14 times and all the extractions gave good color removal. Copyright © 2004 Society of Chemical Industry
Process integration of H2O2 generation and the ammoximation of cyclohexanone
Authors: Liang Xinhua , Mi Zhentao , Wang Yaquan , Wang Li , Zhang Xiangwen , Wu Wei , Min Enze , Fu Songbao
Published: April 2004

The possibility of the integration of the processes of H2O2 generation through isopropanol partial oxidation and ammoximation of cyclohexanone with H2O2 and NH3 TS‐1 catalysed was investigated. The ammoximation of cyclohexanone over TS‐1 with isopropanol as solvent was first studied. The results show that isopropanol can be used as solvent, and the impurities in the H2O2 solution obtained through isopropanol oxidation with only acetone needing to be separated have no harmful effects on the ammoximation of cyclohexanone, suggesting that the process of H2O2 generation through isopropanol oxidation and the ammoximation of cyclohexanone could be directly integrated. Copyright © 2004 Society of Chemical Industry
Genetic approaches and technologies for improving the sustainability of livestock production
Authors: Bishop Stephen C , Woolliams John A
Published: April 2004

Livestock production industries worldwide face considerable conflicting challenges and pressures. In developed countries the challenge is to remain sustainable and competitive in the face of declining prices and increasing costs, competition and public pressures. In developing countries the strong increase in demand for livestock products must be met in circumstances where infrastructure is often minimal, there are limitations on inputs and the environment places demands on management and on the adaptive fitness of the livestock. In both situations, solutions to these problems must be sustainable and appropriate, yet be technically feasible, cost‐effective and publicly acceptable. This paper summarises the impact of two technologies that will make considerable contributions to sustainable livestock production systems, namely information technology and genetic technologies that utilise naturally occurring genetic variation. Genetic technologies are inherently sustainable owing to the permanent and cumulative nature of genetic change, and range from simple to sophisticated. They include breed choice, within‐breed selection and the use of genetic markers linked to gene variants conferring favourable attributes. Breeding goals include increased output, where required, enhanced product quality and increased disease resistance. These goals are illustrated by examples for the hill sheep and pig sectors in the UK and by challenges facing animal health in developing countries. Central to all examples is the gathering, management and interpretation of information, ie information technology, which enables rational genetic and management decisions to be made. Additionally, in all sustainable livestock production systems the maintenance and utilisation of biodiversity will help manage the risks of today as well as the challenges of the future. Copyright © 2004 Society of Chemical Industry
A survey of the fungal contamination and presence of ochratoxin A and zearalenone on Spanish feed and raw materials
Authors: Jaimez Judith , Fente Cristina A , Franco Carlos M , Cepeda Alberto , Vázquez Beatriz I
Published: April 2004

The incidence of fungal contamination in 91 samples of feed and raw materials used for animal feeding in Spain has been studied. Sample analysis was accomplished in a new culture medium to which a beta‐cyclodextrin had been added, and a comparison with other more usual culture media was performed. Ochratoxin A (OTA) and zearalenone (ZEA) contamination of all the samples was evaluated by RP‐HPLC with fluorescence detection. The fungal genera found, such as Penicillium and Fusarium, included mycotoxigenic strains as OTA and ZEA (33.3 and 26.4% incidence respectively). One sample of corn and another of cotton seed were contaminated with levels of OTA above the 5 and/or 10 µg kg−1 recommended by the legislation of several European countries, whereas none of the samples contaminated with ZEA surpassed the legislation limits suggested by the official agencies. Copyright © 2004 Society of Chemical Industry
Survival of mammalian B104 cells following neurite transection at different locations depends on somal Ca2+ concentration
Authors: Yoo Soonmoon , Bottenstein Jane E. , Bittner George D. , Fishman Harvey M.
Published: April 2004

We report that cell survival after neurite transection in a mammalian neuronal model (cultured B104 cells) critically depends on somal [Ca2+]i, a novel result that reconciles separate long‐standing observations that somal survival decreases with more‐proximal axonal transections and that increased somal Ca2+ is cytotoxic. Using fluorescence microscopy, we demonstrate that extracellular Ca2+ at the site of plasmalemmal transection is necessary to form a plasmalemmal barrier, and that other divalent ions (Ba2+, Mg2+) do not play a major role. We also show that extracellular Ca2+, rather than injury per se, initiates the formation of a plasmalemmal barrier and that a transient increase in somal [Ca2+]i significantly decreases the percentage of cells that survive neurite transection. Furthermore, we show that the increased somal [Ca2+]i and decreased cell survival following proximal transections are not due to less frequent or slower plasmalemmal sealing or Ca2+ entry through plasmalemmal Na+ and Ca2+ channels. Rather, the increased somal [Ca2+]i and lethality of proximal neurite injuries may be due to the decreased path length/increased diameter for Ca2+ entering the transection site to reach the soma. A ryanodine block of Ca2+ release from internal stores before transection has no effect on cell survival; however, a ryanodine‐ or thapsigargin‐induced buildup of somal [Ca2+]i before transection markedly reduces cell survival, suggesting a minor involvement of Ca2+‐induced release from internal stores. Finally, we show that cell survival following proximal injuries can be enhanced by increasing intracellular Ca2+ buffering capacity with BAPTA to prevent the increase in somal [Ca2+]i. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 137–153, 2004
Model of the early development of diffuse gastric cancer in E‐cadherin mutation carriers and its implications for patient screening
Authors: Carneiro Fátima , Huntsman David G , Smyrk Thomas C , Owen David A , Seruca Raquel , Pharoah Paul , Caldas Carlos , Sobrinho‐Simões Manuel
Published: April 2004

Hereditary diffuse gastric cancer (HDGC) is a familial cancer syndrome caused, in 30–40% of cases, by germline mutations of the E‐cadherin/CDH1 gene. The presence of clinically undetectable early gastric cancers has been previously reported in ten of ten prophylactic gastrectomies from germline E‐cadherin mutation carriers. In the present study, detailed maps of the distribution of invasive cancers in nine of these ten stomachs were produced and precursor lesions of HDGC searched for. The nine gastrectomy specimens contained from 1 to 161 foci of early diffuse gastric cancer, occupying 0.005–2.96% of the gastric mucosa. Seven specimens contained focal in situ signet ring carcinoma. Pagetoid spread of signet ring cells was observed beneath the epithelial lining of gastric foveolae/glands. Helicobacter pylori organisms and associated pathology were absent from all cases. Two‐dimensional maps of the gastrectomy specimens revealed lesions throughout the gastric mucosa without evidence of antral clustering. The distribution and size of the cancers in the gastrectomy specimens indicate that standard endoscopic screening with random or geographically targeted biopsies is unlikely to provide sufficiently sensitive clinical screening for at‐risk individuals. An in situ precursor of signet ring carcinoma was identified and a model for neoplastic progression in the setting of HDGC is proposed. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
A physical reference state unifies the structure‐derived potential of mean force for protein folding and binding
Authors: Liu Song , Zhang Chi , Zhou Hongyi , Zhou Yaoqi
Published: April 2004

Extracting knowledge‐based statistical potential from known structures of proteins is proved to be a simple, effective method to obtain an approximate free‐energy function. However, the different compositions of amino acid residues at the core, the surface, and the binding interface of proteins prohibited the establishment of a unified statistical potential for folding and binding despite the fact that the physical basis of the interaction (water‐mediated interaction between amino acids) is the same. Recently, a physical state of ideal gas, rather than a statistically averaged state, has been used as the reference state for extracting the net interaction energy between amino acid residues of monomeric proteins. Here, we find that this monomer‐based potential is more accurate than an existing all‐atom knowledge‐based potential trained with interfacial structures of dimers in distinguishing native complex structures from docking decoys (100% success rate vs. 52% in 21 dimer/trimer decoy sets). It is also more accurate than a recently developed semiphysical empirical free‐energy functional enhanced by an orientation‐dependent hydrogen‐bonding potential in distinguishing native state from Rosetta docking decoys (94% success rate vs. 74% in 31 antibody–antigen and other complexes based on Z score). In addition, the monomer potential achieved a 93% success rate in distinguishing true dimeric interfaces from artificial crystal interfaces. More importantly, without additional parameters, the potential provides an accurate prediction of binding free energy of protein–peptide and protein–protein complexes (a correlation coefficient of 0.87 and a root‐mean‐square deviation of 1.76 kcal/mol with 69 experimental data points). This work marks a significant step toward a unified knowledge‐based potential that quantitatively captures the common physical principle underlying folding and binding. A Web server for academic users, established for the prediction of binding free energy and the energy evaluation of the protein–protein complexes, may be found at http://theory.med.buffalo.edu. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Virtual screening for inhibitors of human aldose reductase
Authors: Kraemer Oliver , Hazemann Isabelle , Podjarny Alberto D. , Klebe Gerhard
Published: April 2004

The inhibition of aldose reductase (AR) provides an interesting strategy to prevent the complications of chronic diabetes. Although a large number of different AR inhibitors are known, very few of these compounds exhibit sufficient efficacy in clinical trials. We performed a virtual screening based on the ultrahigh resolution crystal structure of the inhibitor IDD594 in complex with human AR. AR operates on a large scale of structurally different substrates. To achieve this pronounced promiscuity, the enzyme can adapt rather flexibly to its substrates. Likewise, it has a similar adaptability for the binding of inhibitors. We applied a protocol of consecutive hierarchical filters to search the Available Chemicals Directory. In the first selection step, putative ligands were chosen that exhibit functional groups to anchor the anion‐binding pocket of AR. Subsequently, a pharmacophore model based on the binding geometry of IDD594 and the mapping of the binding pocket in terms of putative “hot spots” of binding was applied as a second consecutive filter. In a third and final filtering step, the remaining candidate molecules were flexibly docked into the binding pocket of IDD594 with FlexX and ranked according to their estimated DrugScore values. Out of 206 compounds selected by this search and complemented by a cluster analysis and visual inspection, 9 compounds were selected and subjected to biological testing. Of these, 6 compounds showed IC50 values in the micromolar range. According to the proposed binding mode, the two inhibitors BTB02809 (IC50 = 2.4 ± 0.5 μM) and JFD00882 (IC50 = 4.1 ± 1.0 μM) both place a nitro group into the hydrophobic specificity pocket of human AR in an orientation coinciding with the position of the bromine atom of IDD594. The interaction of this Br with Thr113 has been identified as a key feature that is responsible for selectivity enhancement. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Probabilistic description of protein alignments for sequences and structures
Authors: Koike Ryotaro , Kinoshita Kengo , Kidera Akinori
Published: April 2004

A number of equally optimal alignments inherently exist in the sequence and structure comparisons among proteins. To represent the sub‐optimal alignments systematically, we have developed a method of generating probabilistic alignments for sequences and structures, by which the correspondence between pairs of residues is evaluated in a probabilistic manner. Our method uses the periodic boundary condition to avoid the entropy artifact favoring full‐length matches. In the structure comparison, the environmental effects are incorporated by the mean‐field approximation. We applied this method in comparisons of two pairs of proteins with internal symmetry; the first set were proteins of TIM‐barrel fold and the second were β‐trefoil fold. These pairs are expected to have distinct sub‐optimal alignments suitable for probabilistic description with the periodic boundary. It was shown that the sequence and structure alignments are consistent with each other and that the alignments with the highest probability represent circular permutation. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Prediction of the bonding states of cysteines Using the support vector machines based on multiple feature vectors and cysteine state sequences
Authors: Chen Yu‐Ching , Lin Yeong‐Shin , Lin Chih‐Jen , Hwang Jenn‐Kang
Published: April 2004

The support vector machine (SVM) method is used to predict the bonding states of cysteines. Besides using local descriptors such as the local sequences, we include global information, such as amino acid compositions and the patterns of the states of cysteines (bonded or nonbonded), or cysteine state sequences, of the proteins. We found that SVM based on local sequences or global amino acid compositions yielded similar prediction accuracies for the data set comprising 4136 cysteine‐containing segments extracted from 969 nonhomologous proteins. However, the SVM method based on multiple feature vectors (combining local sequences and global amino acid compositions) significantly improves the prediction accuracy, from 80% to 86%. If coupled with cysteine state sequences, SVM based on multiple feature vectors yields 90% in overall prediction accuracy and a 0.77 Matthews correlation coefficient, around 10% and 22% higher than the corresponding values obtained by SVM based on local sequence information. Proteins 2004;55:000–000. © 2004 Wiley‐Liss, Inc.
Toward the active conformations of rhodopsin and the β2‐adrenergic receptor
Authors: Gouldson Paul R. , Kidley Nathan J. , Bywater Robert P. , Psaroudakis Georgios , Brooks Harry D. , Diaz Constantino , Shire David , Reynolds Christopher A.
Published: April 2004

Using sets of experimental distance restraints, which characterize active or inactive receptor conformations, and the X‐ray crystal structure of the inactive form of bovine rhodopsin as a starting point, we have constructed models of both the active and inactive forms of rhodopsin and the β2‐adrenergic G‐protein coupled receptors (GPCRs). The distance restraints were obtained from published data for site‐directed crosslinking, engineered zinc binding, site‐directed spin‐labeling, IR spectroscopy, and cysteine accessibility studies conducted on class A GPCRs. Molecular dynamics simulations in the presence of either “active” or “inactive” restraints were used to generate two distinguishable receptor models. The process for generating the inactive and active models was validated by the hit rates, yields, and enrichment factors determined for the selection of antagonists in the inactive model and for the selection of agonists in the active model from a set of nonadrenergic GPCR drug‐like ligands in a virtual screen using ligand docking software. The simulation results provide new insights into the relationships observed between selected biochemical data, the crystal structure of rhodopsin, and the structural rearrangements that occur during activation. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Classification of common functional loops of kinase super‐families
Authors: Fernandez‐Fuentes Narcis , Hermoso Antoni , Espadaler Jordi , Querol Enrique , Aviles Francesc X. , Oliva Baldomero
Published: April 2004

A structural classification of loops has been obtained from a set of 141 protein structures classified as kinases. A total of 1813 loops was classified into 133 subclasses (9 ββlinks, 15 ββhairpins, 31 α–α, 46 α–β and 32 β–α). Functional information and specific features relating subclasses and function were included in the classification. Functional loops such as the P‐loop (shared by different folds) or the Gly‐rich‐loop, among others, were classified into structural motifs. As a result, a common mechanism of catalysis and substrate binding was proved for most kinases. Additionally, the multiple‐alignment of loop sequences made within each subclass was shown to be useful for comparative modeling of kinase loops. The classification is summarized in a kinase loop database located at http://sbi.imim.es/archki. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Predicting blast overpressures caused by vapor cloud explosions in the vicinity of control rooms
Authors: Van Wingerden Kees , Hansen Olav Roald , Foisselon Pierre
Published: April 2004

When considering the consequences of gas explosions in petro‐chemical installutions simple methods are used such as TNT‐equivalenc methods and the Multi‐Energy method. These methods howewr, do not take into account directional effects, focusing effects, factors related to the source of the explosion (initial strength, shape) and reflections. FLACS, a 3‐D CFD tool, allows for all factors mentioned including focusing on effects and reflections near buildings.

A comparison of the CFD‐method including the two traditional prediction methods for a practical case demonstrates the application areas of the FLACS method as well as the limitations of the traditional methods.
Developing screening risk evalution criteria for facility siting vapor cloud explosion hazards
Authors: Hobbs Douglas H.
Published: April 2004

The building location evaluation methodologies published in API RP 752, Management of Hazards Associated with Location of Process Plant Buildings/CMA Manager's Guide [1] and Guidelines for Evaluating Process Plant Buildings for External Explosions and Fires [2], provide the option of performing a “screening risk analysis”.

As with any risk evaluation the results should be judged against a “level of goodness” or evaluation criteria so that meaningful conclusions can be made from the evaluation. These evaluation criteria must be developed in consideration of the hazards evaluated, the extent and purpose of screening risk analysis, and the possible scrutiny the study may receive as part of compliance audits or post‐accident investigations.

This paper addresses underlying conceptual issues associated with developing company‐specific evaluation criteria for facility siting risk screening evaluations with regards to vapor cloud explosion (VCE) hazards. The CCPS publication suggests a range of values for individual screening risk evaluation criteria, which companies might consider using as a starting point. The CCPS publication offers, for the first time, a risk measure called “Aggregate Risk” as a tool to distinguish between risks to workers and risks to the public.

Despite this guidance, the development and application of risk evaluation criteria remains an emerging science and practice. While risk issues extend well beyond facility siting problems, many companies are currently faced with spending millions of dollars to implement risk reduction measures for process plant buildings. Since all risk cannot be eliminated, a residual risk for individuals and the company, associated with occupying a building, must be identifed to evaluate the appropriateness of building location. To make reasonable and defensible decisions about their buildings, companies are developing and applying risk evaluation criteria.