bluuebunny/crossref_metadata_2025 huggingface dataset:
Maximizing the grain growth rate during the disorder‐to‐order transition in block copolymer melts
Authors: Kim W. G. , Garetz B. A. , Newstein M. C. , Balsara N. P.
Published: August 2002

The factors controlling grain growth during the disorder‐to‐order transition in a polystyrene‐block‐polyisoprene copolymer melt were studied with time‐resolved depolarized light scattering. The ordered phase consisted of hexagonally packed polyisoprene cylinders, and the order–disorder‐transition temperature of the block copolymer (TODT) was 132 ± 1 °C. Our objective was to identify the temperature at which the grain growth rate was maximized (Tmax) and compare it with theoretical predictions. We conducted seeded grain growth experiments, which comprised two steps. In the first step, which lasted for 43 min, the sample was cooled from the disordered state to 124 °C. This resulted in the formation of a small number of ordered grains or seeds. This was followed by a second step in which the sample was heated to temperatures between 124 and 132 °C and the seeds grew with time. Our objective was to study grain growth at different temperatures starting from the same initial condition. The value of Tmax obtained experimentally was 128 °C. The theoretically predicted value of Tmax, based entirely on the rheological properties of the disordered sample and TODT, was also 128 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2231–2242, 2001
The system of belief inventory (SBI‐15): a validation study in Israel
Authors: Baider Lea , Holland Jimmie C. , Russak Simcha M. , Kaplan De‐Nour Atara
Published: August 2002

This study focused on the validation of measures assessing religiosity by means of three self‐report instruments: the System of Belief Inventory (SBI‐15R), the Religious Orientation Inventory (ROI), and the Index of Core Spiritual Experiences (INSPIRIT). These instruments were developed and validated previously in the United States.

The study measured the extent to which the self‐reports maintain their validity when administered in a different country with its own distinct language, culture and religion (e.g. Israel).

It was found that all three self‐reports have very good external validity and high convergent reliability, with the SBI demonstrating extremely high internal reliability. Copyright © 2001 John Wiley & Sons, Ltd.
Changes in arterial oxygen tension when weaning neonates from inhaled nitric oxide*†
Authors: Sokol Gregory M. , Fineberg Naomi S. , Wright Linda L. , Ehrenkranz Richard A.
Published: August 2002

We set out to evaluate changes in arterial oxygen tension (PaO2) when weaning neonates from inhaled nitric oxide (INO). We reviewed the records of 505 prospectively collected INO weaning attempts on 84 neonates with hypoxic respiratory failure. PaO2 values before and 30 min after weaning attempts were recorded. Relationships between change in PaO2 and decreases in INO concentrations were investigated using regression analysis and ANOVA.

PaO2 decreased (−18.7 ± 1.8 torr; P < 0.001); when weaning INO. A stepwise decline in PaO2 was observed weaning INO from 40 ppm. The greatest decline occurred when INO was discontinued (−42.1 ± 4.1 torr). Forward stepwise multiple regression using variables with significant relationships to the decline in PaO2 identified the specific dose reduction 7(P < 0.001), the prewean PaO2 (P < 0.001), and surfactant therapy (P = 0.018) as the variables best describing the change in PaO2(P = 0.004, r = 0.51).

In conclusion, a graded decline in PaO2 occurs when reducing INO. INO should be weaned to less than 1 ppm before discontinuing its use. Prior surfactant treatment appears to enhance the oxygenation reserve when weaning INO. Pediatr Pulmonol. 2001; 32:14–19. © 2001 Wiley‐Liss,Inc.
Effect of clarithromycin on airway obstruction and inflammatory markers in induced sputum in cystic fibrosis: A pilot study*
Authors: Ordoñez Claudia L. , Stulbarg Michael , Grundland H. , Liu Jane T. , Boushey Homer A.
Published: August 2002

To determine whether macrolide antibiotics improve pulmonary function and decrease airway inflammation in cystic fibrosis (CF), we treated 10 patients (females; aged 19–26 years, all colonized with P. aeruginosa, none with atypical Mycobacteria) with 3 weeks of placebo, followed by 6 weeks of clarithromycin (500 mg BID) in a single‐blind prospective study. We also determined the safety of sputum induction and the reproducibility of assessing inflammatory markers in induced sputum. Subjects performed spirometry and underwent sputum induction (12‐min inhalation of 3% saline) at 3‐week intervals.

We found that sputum induction was well‐tolerated. We also found that the reproducibility was high for neutrophil (PMN) number (R = 0.87, P = 0.009), interleukin (IL)‐8 (R = 0.73, P < 0.05, free neutrophil elastase (NE) (R = 0.82, P < 0.05), and myeloperoxidase (MPO) levels (R = 0.86, P < 0.05), but was less so for tumor necrosis factor (TNF)‐α (R = −0.15, P = 0.7). We found no significant difference in pulmonary function after 6 weeks of treatment with clarithromycin (FEV1 (% predicted) (mean ± SEM), 2.2 ± 0.9 (60 ± 24%) vs. 2.3 ± 1 (61 ± 29%)), and no significant differences in any of the inflammatory indices measured. The median (and range) values before and after treatment for indices of airway inflammation in the induced sputum samples were: for PMNs, 8 (1–326) and 21 (0.2 –175) × 106 cells/mL sputum; for IL‐8, 156 (24–656) and 202 (16–680) ng/mL; for free NE, 260 (31–1,264) and 237 (49–1,048) μg/mL; for TNF‐α, 20 (7–128) and 35 (17–87) pg/mL; and for MPO, 169 (13–960) and 195 (14–816) μg/mL.

We conclude that clarithromycin is not uniformly effective in improving airway obstruction or in decreasing airway inflammation in patients with CF. Pediatr Pulmonol. 2001; 32:29–37. © 2001 Wiley‐Liss, Inc.
Overexpression of the homeobox gene HOXC8 in human prostate cancer correlates with loss of tumor differentiation*
Authors: Waltregny David , Alami Younes , Clausse Nathalie , Leval Jean de , Castronovo Vincent
Published: August 2002

BACKGROUND

Homeobox (HOX)‐containing proteins have been identified as regulators controlling the coordinated expression of genes involved in development and differentiation. Recent data also suggest a possible involvement of HOX genes in malignant transformation and/or progression. We have previously shown that HOXC8 expression was selectively turned on in human cervix cancer cells compared with normal keratinocytes, suggesting that HOXC8 may be involved in the process leading to the transformation of cervix keratinocytes [Alami et al.: Biochem Biophys Res Commun 257:738–745, 1999].

METHODS

RT‐PCR and in situ hybridization experiments were performed to investigate the expression and cell type localization of HOXC8 transcripts in human prostate cancer cell lines and tissues. In situ hybridization was performed with the use of an HOXC8 anti‐sense digoxigenin‐labeled probe to investigate HOXC8 mRNA expression in 27 prostate cancer tissue specimens.

RESULTS

Out of the three human prostate cancer cell lines tested, DU‐145 and PC3 but not LNCaP cells expressed detectable amount of HOXC8 transcripts. Results from in situ hybridization experiments demonstrated that HOXC8 gene was expressed mainly in malignant epithelial cells. Furthermore, the staining intensity in epithelial cells was significantly increased in high Gleason score carcinomas (scores 7–9, n = 12; labeling intensity 2 + to 3 +) compared with the one observed in low and intermediate Gleason score tumors (scores 3–6, n = 15; labeling intensity 0 and 1 +) (ANOVA test, P < 0.0001).

CONCLUSIONS

Our data showing that HOXC8 overexpression is associated with the loss of tumor differentiation in human prostate cancer suggests that HOXC8 may play a role in the acquisition of the invasive and metastatic phenotype of this malignancy. Prostate 50: 162–169, 2002. © 2002 Wiley‐Liss, Inc.
Down‐regulation of prostasin serine protease: A potential invasion suppressor in prostate cancer
Authors: Chen Li‐Mei , Hodge G. Byron , Guarda Luis A. , Welch James L. , Greenberg Norman M. , Chai Karl X.
Published: August 2002

BACKGROUND

Prostasin is a serine protease predominantly expressed in normal prostate epithelial cells. The biological function of prostasin has not been determined.

METHODS

Western blot and RT‐PCR analyses were used to examine the expression of prostasin in prostate cancer cell lines. Immunohistochemistry was used to evaluate prostasin protein expression in human prostate cancer. An in vitro Matrigel invasion assay was used to test the invasiveness of prostate cancer cell lines forced to express recombinant prostasin.

RESULTS

Both prostasin protein and mRNA were found to be expressed in normal human prostate epithelial cells and a non‐invasive human prostate cancer cell line, the LNCaP, but neither was found in invasive human prostate cancer cell lines DU‐145 and PC‐3. Prostasin mRNA expression was absent in invasive prostate cancer cell lines of a transgenic mouse model. Immunohistochemistry analysis showed that prostasin protein expression is down‐regulated in high‐grade prostate cancer. Transfection of DU‐145 and PC‐3 cells with a full‐length human prostasin cDNA restored prostasin expression and reduced the in vitro invasiveness by 68 and 42%, respectively.

CONCLUSIONS

Our data indicate that prostasin may be implicated in normal prostate biology and is able to suppress prostate cancer invasion in vitro. Prostate 48:93–103, 2001. © 2001 Wiley‐Liss, Inc.
How accurately does prostate biopsy Gleason score predict pathologic findings and disease free survival?
Authors: Narain Vivek , Bianco Fernando J. , Grignon David J. , Sakr Wael A. , Pontes J. Edson , Wood David P.
Published: August 2002

Objective

Due to the significant impact on prognosis by subgrouping of prostatectomy Gleason scores < 7, 7, and > 7, we undertook this study to answer whether the biopsy Gleason score was as predictive of disease free survival and assess the correlation with the prostatectomy Gleason score in a modern prostatectomy series.

Methods

An analysis of 1,031 patients who underwent radical prostatectomy for clinically localized prostate cancer was performed. All data was prospectively collected. The Gleason score was categorized into 3 different groups (< 7, 7, and > 7) for biopsy and prostatectomy specimens. Disease free survival was then analyzed for each group. Discrepancies between scores and outcomes were evaluated.

Results

Accurate correlation was noted in 54.8, 66.8, and 47.4% of Gleason scores < 7, 7, and > 7, respectively. Overall accuracy was 58.3%. Both, biopsy and prostatectomy Gleason score correlated significantly with disease free survival (P = 0.001), furthermore the classification (Gleason scores < 7, 7 and > 7) was highly significant (P = 0.001). Patients with prostatectomy Gleason < 7 tumors had significant survival advantage over those with biopsy Gleason < 7, (P = 0.001). However, disease free survival was superior for patients with biopsy Gleason > 7 than those with prostatectomy Gleason > 7, (P = 0.02). The overall disease free survival was similar among the patients with Gleason score of 7 (P = 0.12).

Conclusions

It appears that biopsy Gleason score, although oftentimes not correlating strongly with the prostatectomy Gleason score, is an important prognostic factor in prostate cancer. There are significant differences in disease free survival between biopsy and prostatectomy Gleason score categories. Prostate 49:185–190, 2001. © 2001 Wiley‐Liss, Inc.
Positioning of anchor groups in protein loop prediction: The importance of solvent accessibility and secondary structure elements
Authors: Wohlfahrt Gerd , Hangoc Vu , Schomburg Dietmar
Published: August 2002

The prediction of loop regions in the process of protein structure prediction by homology is still an unsolved problem. In an earlier publication, we could show that the correct placement of the amino acids serving as an anchor group to be connected by a loop fragment with a predicted geometry is a highly important step and an essential requirement within the process (Lessel and Schomburg, Proteins 1999;37:56–64). In this article, we present an analysis of the quality of possible loop predictions with respect to gap length, fragment length, amino acid type, secondary structure, and solvent accessibility. For 550 insertions and 544 deletions, we test all possible positions for anchor groups with an inserted loop of a length between 3 and 12 amino acids. We could show that approximately 80% of the indel regions could be predicted within 1.5 Å RMSD from a knowledge‐based loop data base if criteria for the correct localization of anchor groups could be found and the loops can be sorted correctly. From our analysis, several conclusions regarding the optimal placement of anchor groups become obvious: (1) The correct placement of anchor groups is even more important for longer gap lengths, (2) medium length fragments (length 5–8) perform better than short or long ones, (3) the placement of anchor groups at hydrophobic amino acids gives a higher chance to include the best possible loop, (4) anchor groups within secondary structure elements, in particular β‐sheets are suitable, (5) amino acids with lower solvent accessibility are better anchor group. A preliminary test using a combination of the anchor group positioning criteria deduced from our analysis shows very promising results. Proteins 2002;47:370–378. © 2002 Wiley‐Liss, Inc.
Structural basis of oncogenic activation caused by point mutations in the kinase domain of the MET proto‐oncogene: Modeling studies
Authors: Miller Maria , Ginalski Krzysztof , Lesyng Bogdan , Nakaigawa Noboru , Schmidt Laura , Zbar Berton
Published: August 2002

Missense mutations in the tyrosine kinase domain of the MET proto‐oncogene occur in selected cases of papillary renal carcinoma. In biochemical and biological assays, these mutations produced constitutive activation of the MET kinase and led to tumor formation in nude mice. Some mutations caused transformation of NIH 3T3 cells. To elucidate the mechanism of ligand‐independent MET kinase activation by point mutations, we constructed several 3D models of the wild‐type and mutated MET catalytic core domains. Analysis of these structures showed that some mutations (e.g., V1110I, Y1248H/D/C, M1268T) directly alter contacts between residues from the activation loop in its inhibitory conformation and those from the main body of the catalytic domain; others (e.g., M1149T, L1213V) increase flexibility at the critical points of the tertiary structure and facilitate subdomain movements. Mutation D1246N plays a role in stabilizing the active form of the enzyme. Mutation M1268T affects the S+1 and S+3 substrate‐binding pockets. Models implicate that although these changes do not compromise the affinity toward the C‐terminal autophosphorylation site of the MET protein, they allow for binding of the substrate for the c‐Abl tyrosine kinase. We provide biochemical data supporting this observation. Mutation L1213V affects the conformation of Tyr1212 in the active form of MET. Several somatic mutations are clustered at the surface of the catalytic domain in close vicinity of the probable location of the MET C‐terminal docking site for cytoplasmic effectors. Proteins 2001;44:32–43. © 2001 Wiley‐Liss, Inc.
Protein flexibility predictions using graph theory
Authors: Jacobs Donald J. , Rader A.J. , Kuhn Leslie A. , Thorpe M.F.
Published: August 2002

Techniques from graph theory are applied to analyze the bond networks in proteins and identify the flexible and rigid regions. The bond network consists of distance constraints defined by the covalent and hydrogen bonds and salt bridges in the protein, identified by geometric and energetic criteria. We use an algorithm that counts the degrees of freedom within this constraint network and that identifies all the rigid and flexible substructures in the protein, including overconstrained regions (with more crosslinking bonds than are needed to rigidify the region) and underconstrained or flexible regions, in which dihedral bond rotations can occur. The number of extra constraints or remaining degrees of bond‐rotational freedom within a substructure quantifies its relative rigidity/flexibility and provides a flexibility index for each bond in the structure. This novel computational procedure, first used in the analysis of glassy materials, is approximately a million times faster than molecular dynamics simulations and captures the essential conformational flexibility of the protein main and side‐chains from analysis of a single, static three‐dimensional structure. This approach is demonstrated by comparison with experimental measures of flexibility for three proteins in which hinge and loop motion are essential for biological function: HIV protease, adenylate kinase, and dihydrofolate reductase. Proteins 2001;44:150–165. © 2001 Wiley‐Liss, Inc.
Role of the carboxy‐termini of tubulin on its chaperone‐like activity
Authors: Sarkar Taradas , Manna Tapas , Bhattacharyya Shankar , Mahapatra Pradip , Poddar Asim , Roy Siddhartha , Pena Jose , Solana Rafael , Tarazona Raquel , Bhattacharyya Bhabatarak
Published: August 2002

Mutational analysis and the enzymatic digestion of many chaperones indicate the importance of both hydrophobic and hydrophilic residues for their unique property. Thus, the chaperone activity of α‐crystallin is lost due to the substitution of hydrophobic residues or upon enzymatic digestion of the negatively charged residues. Tubulin, an eukaryotic cytoskeletal protein, exhibits chaperone‐like activity as demonstrated by prevention of DTT‐induced aggregation of insulin, thermal aggregation of alcohol dehydrogenase, βγ‐crystallin, and other proteins. We have shown that the tubulin lost its chaperone‐like activity upon digestion of its negatively charged C‐termini. In this article, the role of the C‐terminus of individual subunits has been investigated. We observe that the digestion of C‐terminus of β‐subunit with subtilisin causes loss of chaperone‐like activity of tubulin. The contribution of C‐terminus of α‐subunit is difficult to establish directly as subtilisin cleaves C‐terminus of β‐subunit first. This has been ascertained indirectly using a 14‐residue peptide P2 having the sequence corresponding to a conserved region of MHC class I molecules and that binds tightly to the C‐terminus of α‐subunit. We have shown that the binding of P2 peptide to αβ‐tubulin causes complete loss of its chaperone‐like activity. NMR and gel‐electrophoresis studies indicate that the P2 peptide has a significant higher binding affinity for the C‐terminus of α‐subunit compared to that of β‐subunit. Thus, we conclude that both the C‐termini are necessary for the chaperone‐like activity of tubulin. Implications for the chaperone functions in vivo have been discussed. Proteins 2001;44:262–269. © 2001 Wiley‐Liss, Inc.
Bias‐free separation of internal and overall motion of biomolecules
Authors: Schieborr Ulrich , Rüterjans Heinz
Published: August 2002

Collective internal motions are known to be important for the function of biological macromolecules. It has been discussed in the past whether the application of superimposing algorithms to remove the overall motion from a structural ensemble introduces artificial correlations between distant atoms. Here we present a new method to eliminate residual rotation and translation from cartesian modes derived from a normal mode analysis or from a principal component analysis. Bias‐free separation is based on the idea that the addition of modes of pure rotation/translation can compensate the residual overall motion. Removal of overall motion must reduce the “total amount of motion” (TAM) in the mode. Our algorithm allows to back‐calculate revised covariance matrices. The approach was applied to two model systems that show residual overall motion, when analyzed using all atoms as reference for the superimposing algorithm. In both cases, our algorithm was capable of eliminating residual covariances caused by the overall motion, while retaining internal covariances even for very distant atoms. A structural ensemble obtained for a 13‐ns molecular dynamics simulation of the protein Ribonuclease T1 showed a covariance matrix of the corrected modes with significantly sharper contours after applying the bias‐free separation. Proteins 2001;45:207–218. © 2001 Wiley‐Liss, Inc.
Acaricide toxicity and resistance in larvae of different strains of Tetranychus urticae and Panonychus ulmi (Acari: Tetranychidae)
Authors: Nauen Ralf , Stumpf Natascha , Elbert Alfred , Zebitz Claus P W , Kraus Wolfgang
Published: August 2002

The toxicities of eight structurally different acaricidal compounds to six‐legged larvae (first motile stage) of three laboratory strains of the two‐spotted spider mite, Tetranychus urticae, and the European red mite, Panonychus ulmi, were evaluated following spray application. The larvae of five field‐derived strains of T urticae originating from France, Italy, Brazil, California and Florida were also tested for their susceptibilities to discriminating concentrations of several acaricides resulting in 95% mortality when applied to the organophosphate‐resistant laboratory reference strain WI. The spray bioassay used was robust and gave repeatable results with a wide range of acaricidal compounds, irrespective of their mode of action (ovo‐larvicides or primarily acting on motile life stages). Compounds tested were abamectin, azocyclotin, chlorpyrifos, clofentezine, deltamethrin, fenpyroximate, hexythiazox and pyridaben. Larvae of one of the laboratory strains of T urticae, AK, originally collected in Japan in 1996 and maintained without further selection pressure, exhibited 2000‐ and >4000‐fold resistance to the mitochondrial electron transport inhibitors pyridaben and fenpyroximate, respectively. Another strain of T urticae, AU, obtained from Australia and maintained in the laboratory under selection with hexythiazox and clofentezine since 1987 showed >770‐ and >1000‐fold resistance to clofentezine and hexythiazox, respectively. The same resistance pattern was observed against larvae of a laboratory strain of P ulmi, CE, also selected with hexythiazox. Larvae of one of the field‐derived strains of T urticae, BR, showed a lower susceptibility to a number of compounds, whilst the others were susceptible to all compounds except the organophosphates.

© 2001 Society of Chemical Industry
The role of glutathione S‐transferases in the detoxification of some organophosphorus insecticides in larvae and pupae of the yellow mealworm, Tenebrio molitor (Coleoptera: Tenebrionidae)
Authors: Kostaropoulos Iason , Papadopoulos Athanasios I , Metaxakis Athanasios , Boukouvala Evridiki , Papadopoulou‐Mourkidou Euphemia
Published: August 2002

The correlation between the natural levels of glutathione S‐transferase (GST) and the tolerance to the organophosphorus insecticides parathion‐methyl and paraoxon‐methyl, as well as the interaction of affinity‐purified enzyme and the insecticides were investigated in order to collect further information on the role of the glutathione S‐transferase system as a mechanism of defence against insecticides in insects. The studies were carried out on the larvae and pupae of the coleopteran Tenebrio molitor L, which exhibit varying natural levels of GST activity.

Stage‐dependent susceptibility of the insect against insecticides was observed during the first 24 h. However, 48 h after treatment, the KD50 value increased significantly due to the recovery of some individuals. Simultaneous injection of insecticide with compounds which inhibit GST activity in vitro caused an alteration in susceptibility of insects 24 or 48 h post‐treatment, depending on stage and insecticide used. Inhibition studies combined with competitive fluorescence spectroscopy revealed that the insecticides probably bind to the active site of the enzyme, thus inhibiting its activity towards 1‐chloro‐2,4‐dinitrobenzene in a competitive manner. High‐performance liquid chromatography and gas chromatography revealed that T molitor GST catalyses the conjugation of the insecticides studied to a reduced form of glutathione (GSH). From the above experimental results, it is considered that GST offers a protection against the organophosphorus insecticides studied by active site binding and subsequent conjugation with GSH.

© 2001 Society of Chemical Industry
Natural products as insecticides: the biology, biochemistry and quantitative structure–activity relationships of spinosyns and spinosoids
Authors: Sparks Thomas C , Crouse Gary D , Durst Gregory
Published: August 2002

The spinosyns, a novel family of insecticidal macrocyclic lactones, are active on a wide variety of insect pests, especially lepidopterans and dipterans. The biological activity of a mixture (spinosad; Tracer®, Spin‐Tor®, Success®) of the two most abundant spinosyns (spinosyns A and D) against pest insects is on a par with that of many pyrethroid insecticides. The spinosyns also exhibit a very favorable environmental and toxicological profile, and possess a mode of action that appears unique, with studies to date suggesting that both nicotinic and gamma‐aminobutryic acid receptor functions are altered in a novel manner. Compared to pyrethroids such as cypermethrin, spinosyn A is slow to penetrate into insect larvae such as tobacco budworm larvae (Heliothis virescens); however, once inside the insect, spinosyn A is not readily metabolized. To date, more than 20 spinosyns and more than 800 spinosoids (semi‐synthetic analogs) have been isolated or synthesized, respectively. Artificial neural network‐based quantitative structure activity relationship (QSAR) studies for the spinosyns suggested that modification of the 2′,3′,4′‐tri‐O‐methylrhamnosyl moiety could improve activity and several spinosoids incorporating these modifications exhibited markedly improved lepidopteran activity compared to spinosad. Multiple linear regression‐based QSAR studies also suggest that whole molecule properties such as CLogP and MOPAC dipole moment can explain much of the biological activity observed for the spinosyns and closely related spinosoids.

© 2001 Society of Chemical Industry
New developments in insecticide resistance in the glasshouse whitefly (Trialeurodes vaporariorum) and the two‐spotted spider mite (Tetranychus urticae) in the UK
Authors: Gorman Kevin , Hewitt Fiona , Denholm Ian , Devine Gregor J
Published: August 2002

A recent survey of insecticide resistance in two of the most problematic pests in UK glasshouses revealed some new developments. At least some individuals in all UK samples of Trialeurodes vaporariorum that were tested resisted the insect growth regulator (IGR) buprofezin. The most strongly resistant strains were unaffected by the field application rate of this compound, and even samples from populations that had never been exposed to buprofezin contained individuals that survived the highest concentration applied (10 000 mg litre−1). The field rate of buprofezin was shown to select for resistance through vapour action alone. The benzophenylurea teflubenzuron, an unrelated IGR, was cross‐resisted by buprofezin‐resistant individuals. There was no evidence of resistance to imidacloprid, but all T vaporariorum strains tested, regardless of origin, exhibited a high innate tolerance to nicotine, when compared with another whitefly species, Bemisia tabaci. Marked resistance to fenbutatin oxide and tebufenpyrad was found in single glasshouse populations of Tetranychus urticae, but these compounds and abamectin appeared to remain highly effective against all other strains collected.

© 2001 Society of Chemical Industry
Probing the shape of a hydrophobic pocket in the active site of δ‐opioid antagonists
Authors: Santagada Vincenzo , Caliendo Giuseppe , Severino Beatrice , Perissutti Elisa , Ceccarelli Francesca , Giusti Laura , Mazzoni Maria Rosaria , Salvadori Severo , Temussi Piero Andrea
Published: August 2002

The change of selectivity and the induction of antagonism by the insertion of 1,2,3,4‐tetrahydroisoquinoline‐3‐carboxylic acid (Tic) in the second position of several opioid peptides have led to the interpretation of Tyr‐Tic as a specific message domain for δ‐opioid antagonists and to the discovery of dipeptides with substantial opioid activity. Selectivity and activity increase enormously when Tyr is substituted by 2′,6′‐dimethyl tyrosine (Dmt), hinting that the side chain of Dmt fits a hydrophobic cavity of the receptor very tightly and precisely. We have investigated the specificity of this fit by systematic changes of the substituents on the aromatic ring of Tyr. Mono‐ and disubstitutions different from 2′,6′‐ invariably lead to catastrophic decreases of activity. The only substitution compatible with retention of substantial antagonism is 2′‐methyl. An analysis of the conformational properties of all analogues reveals that substitutions do not affect the global shape of the molecule significantly. Accordingly, it is possible to use the shape of the different side chains to map the hydrophobic cavity of the receptor. The resulting complementary image is funnel shaped. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Chloride‐induced corrosion of steel in concrete
Authors: Glass G K , Buenfeld N R
Published: August 2002

The corrosion of steel reinforcement in concrete structures induced by chloride ion contamination is a major problem. Deterioration starts with the loss of protection provided by the concrete cover as the result of chloride ingress. This is followed by corrosion initiation and then propagation. Recent advances in models of chloride penetration into concrete, based on mathematical models of the physical transport processes and an analysis of empirical data, have been made. Inhibitive and aggressive properties of solid phases present at the steel which affect corrosion initiation have been identified. Improved methods have been developed to monitor corrosion rates as well as chloride ingress into the concrete cover. An improved understanding of the deterioration processes has led to new developments in repair techniques.
Protective role of Bacopa monniera on morphine induced hepatotoxicity in rats
Authors: Sumathy T. , Subramanian S. , Govindasamy S. , Balakrishna K. , Veluchamy G.
Published: August 2002

The protective effect of Bacopa monniera on morphine induced liver antioxidant levels was studied in rats. Oral administration of alcohol extracts of Bacopa monniera induced a significant hepatoprotective effect. In the morphine treated group, a significant increase of lipid peroxidation and a significant decrease in liver antioxidant enzyme levels were observed. Simultaneous administration of morphine and Bacopa extract prevented these alterations. The results of this study showed that Bacopa monniera alcohol extract exerted a hepatoprotective effect against morphine induced liver toxicity. Copyright © 2001 John Wiley & Sons, Ltd.
Effect of Mucuna urens (horse eye bean) on the gonads of male guinea‐pigs
Authors: Udoh Paul , Ekpenyong Joseph
Published: August 2002

The effect of Mucuna urens (seeds) on the gonads and sex accessory glands of male guinea‐pigs was investigated. Sexually mature guinea‐pigs of proven fertility were administered orally with 70 mg/kg and 140 mg/kg body weight of crude extract daily for 8 weeks respectively. Phytochemical screening of the seeds revealed the presence of alkaloids. No death or weight loss were observed during the duration of treatment. No pregnancy occurred in females mated with the treated males.

Histological observations at high dose (140 mg/kg) showed complete degeneration of sperm in the testicular tubules. In some tubules, the acrosomal cap of the sperm cells was separated from the nuclei which underwent colour changes. In some tubules only the tails were left in the lumen. The spermatids, primary and secondary spermatocytes showed pycnosis while the morphology of spermatogonia and germinal epithelium appeared normal.

Some epididymides were devoid of sperm while others contained degenerated spermatozoa and cell debris. In the prostate gland there was collapse of the villi and reduction of secretion in both the prostate and seminal vesicles. At low doses (70 mg/kg), there was spermatogenic arrest at spermatid stage. These observations have shown that M. urens is a potential male antifertility agent. Copyright © 2001 John Wiley & Sons, Ltd.
Qualitative and quantitative olfactometric evaluation of different concentrations of ethanol peppermint oil solutions
Authors: Krone D. , Mannel M. , Pauli E. , Hummel T.
Published: August 2002

Selection of an adequate placebo is a major problem in clinical trials of Euminz® (10% peppermint oil/ethanol) which is used topically for the treatment of tension‐type headache. This randomized, controlled, double‐blind, cross‐over study was performed to investigate whether there are qualitative differences between 10%, 1%, 0.5%, 0.1%, and 0% peppermint oil. Forty‐one healthy subjects participated (age range 21–28 years); they rated both intensity, and hedonic tone of the stimuli. Verbal descriptions were combined to multiple response sets (MRS). In addition, the trigeminal impact of odorants was determined. Intensity ratings and MRS ‘menthol like’ and ‘alcohol/solvent’ changed with stimulus concentration. However, intensity had no significant effect on hedonics, trigeminal impact, or the number of descriptive items used. When MRS ‘menthol like’ and ‘alcohol/solvent’ were analysed after being weighted with intensity ratings, changes in relation to stimulus concentration were lost. Thus, the differences between the five concentrations of peppermint oil were—to their largest part—due to changes in stimulus intensity. Considering the large day‐to‐day variability of olfactory sensitivity the present data support the hypothesis that the odour quality of 10% peppermint oil cannot be discriminated from the odour of 0.1%, 0.5%, or 1% peppermint oil when tested on separate days. Copyright © 2001 John Wiley & Sons, Ltd.
In vitroantiprotozoal activity of extract and compounds from the stem bark ofCombretum molle
Authors: Asres K. , Bucar F. , Knauder E. , Yardley V. , Kendrick H. , Croft S. L.
Published: August 2002

The antiprotozoal activity of the Ethiopian medicinal plantCombretum molle(R. Br. ex G. Don.) Engl & Diels (Combretaceae) was evaluated byin vitrotesting againstPlasmodium falciparum, Trypanosoma brucei rhodesiense, Trypanosoma cruziandLeishmania donovani. The acetone fraction of the stem bark of this plant prepared by soxhlet extraction was inactive against the intracellular amastigotes ofL. donovaniandT. cruziin murine peritoneal macrophages but showed significant activity against extracellularT. b. rhodesienseblood stream form trypomastigotes and trophozoites ofP. falciparumwith IC50values of 2.19 and 8.17 μg/mL, respectively. Phytochemical examination of the bioactive fraction resulted in the isolation of two tannins and two oleanane‐type pentacyclic triterpene glycosides. One of the tannins was identified as the ellagitannin, punicalagin, whilst the structure of the other (CM‐A) has not yet been fully elucidated. The saponins that were characterized as arjunglucoside (also called 4‐epi‐sericoside) and sericoside displayed no activity against any of the four species of protozoa tested. On the other hand, punicalagin and CM‐A had IC50values of 1.75 and 1.50 μM, respectively, againstT. b. rhodesienseand were relatively less toxic to KB cells (cytotoxic/antiprotozoal ratios of 70 and 48, respectively). The tannins also showed intermediate activity againstP. falciparum, although their selectivity against these parasites was less favourable than the above. It appears that our findings are the first report of hydrolysable tannins exhibiting antitrypanosomal and antiplasmodial activities. Copyright © 2001 John Wiley & Sons, Ltd.
Quality and reliability information integration for design evaluation of fixture system reliability
Authors: Jin Jionghua (Judy) , Chen Yong
Published: August 2002

Quality and reliability are two important factors in manufacturing‐system design. However, the analysis and optimization of manufacturing‐system reliability and product quality are normally conducted separately in practice. There is no general framework to integrate these two important factors, quantitatively analyze the interactions between them, and further study their integrated effects on the manufacturing‐system performance. In this paper, the QR‐Co‐Effect of product/part quality and manufacturing‐system component reliability is investigated in an assembly fixture system. The concept, model and analysis of QR‐Co‐Effect are addressed in this paper. Copyright © 2001 John Wiley & Sons, Ltd.
A performance study for multivariate location and shape estimators
Authors: Wisnowski James W. , Simpson James R. , Montgomery Douglas C.
Published: August 2002

Exploratory data‐analysis methods and empirical model‐building techniques often attempt to determine the center and spread of multivariate data in order to determine the relative location of observations. The most common measure of multivariate location is the Mahalanobis distance. This measure uses standard mean and covariance matrix estimators for the center and spread. Outliers tend to influence these standard measures such that the corresponding Mahalanobis distances are inappropriately large for data near the true centroid, and relatively small for true outliers. As such, robust measures of location and spread are needed. Many robust measures have been proposed including the minimum covariance determinant, and the minimum volume ellipsoid. It is not clear how these methods perform under various data settings. We perform a comprehensive evaluation of the most referenced methods from the literature. A Monte Carlo simulation study is used to generate data without outliers and data with outliers dispersed separately and in groups or clouds. The methods are evaluated in terms of their ability to detect outliers and their ability not to signal false alarms for clean data. The findings from the study indicate that, although several methods display consistently solid performance, the method of Rocke and Woodruff performs the overall best. Copyright © 2002 John Wiley & Sons, Ltd.
Ab initio molecular modeling of 13C NMR chemical shifts of polymers. 1. Ethylene–norbornene copolymers
Authors: Ragazzi Massimo , Carbone Paola , Ferro Dino R.
Published: August 2002

Cycloolefin copolymers (COC) have recently raised much interest because of their excellent thermal and optical properties, largely determined by the chain composition and stereochemistry. Previous force‐field computations allowed us to define the main conformational characteristics of ethylene–norbornene (E–N) copolymers and to contribute to the elucidation of their microstructure on the basis of empirical relationships between conformation and 13C nuclear magnetic resonance (NMR) chemical shifts. A thorough test of ab initio 13C chemical shifts computations [gauge‐invariant atomic orbitals (GIAO)] on known cases shows that the agreement with experimental data is quite good, especially with the MPW1PW91 density functional theory (DFT), using the 6‐311+G(2d,p) basis set on properly energy‐minimized structures. We applied this method on proper model compounds to confirm the signal assignment of the spectra of E–N copolymers in the presence of norbornene microblocks, where strong effects arising from ring distortions are expected to occur. The results nicely confirm the latest assignment of norbornene signals belonging to ENNE sequences. This shows the great potentialities of GIAO/DFT computations with regard to complex spectra interpretation and polymer microstructural investigations. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Wannier‐type atomic functions and chemical bonding in crystals
Authors: Smirnov V. P. , Evarestov R. A. , Usvyat D. E.
Published: August 2002

A new method of chemical bonding analysis in crystalline solids is suggested. Wannier functions centered on atoms and related to upper valence and lower conduction bands of a crystal [Wannier‐type atomic orbitals (WTAO)] are proposed to play a part of atom‐like functions in population analysis. A straightforward variational procedure is formulated for generation of WTAO from Bloch functions (crystalline orbitals) calculated on a basis of plane waves (PW), LCAO, or any other set of functions. The advantages of the proposed approach compared to the traditional population analysis of Mulliken or Löwdin type on the basis of atomic orbitals are discussed. The proposed approach is applied to analyze the local properties of the electronic structure of Si and GaAs crystals obtained by Hartree–Fock LCAO method. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Density functional study of the relative reactivity in the concerted 1,3‐dipolar cycloaddition of nitrile ylide to disubstituted ethylenes
Authors: Liao Hsin‐Yi , Su Ming‐Der , Chung Wen‐Sheng , Chu San‐Yan
Published: August 2002

Density functional theory was used to perform a theoretical evaluation of (E)‐1,2‐disubstituted ethylenes as dipolarophiles for the 1,3‐dipolar cycloaddition reaction. The reactivities of electron‐withdrawing and ‐donating substituted ethylenes were examined by estimating their activation energies. The calculated activation energies predicted that the most reactive species is (E)‐1,2‐C2H2(NO)2, whereas the least reactive is (E)‐2‐butene. Namely, it was demonstrated that 16‐electron 1,3‐dipole reactants with more electropositive substituents in terminal positions and ethylenes that possess more strongly electron‐withdrawing substituents facilitate 1,3‐dipolar cycloaddition reactions. All of the theoretical results can be rationalized using the configuration mixing model. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 318–323, 2001
The structures and properties of cis‐ and trans‐MeCl2(NH3)2, Me=Pd and Pt complexes, in ground and excited states*
Authors: Hill Glake , Gora Robert. W. , Roszak Szczepan , Leszczyński Jerzy
Published: August 2002

Studies of structures, energetics, and charge distribution were performed for ground and lowest excited electronic states of MeCl2(NH3)2, Me=Pd and Pt complexes. Despite the similarity of the Pd and Pt elements, the differences in isomerization energies, ground‐excited state separation energy, and electronic density distribution are significant. The MeN and MeCl bonds possess a different nature with the Cl accepting and the NH3 group donating electrons to the central metal. The bonds are more polarized in Pt‐based complexes. The electronic excitations involve mostly the metal atom, and although they do not change the structure drastically, the excitations do, however, impact the charge distribution. Interaction energy decomposition for the ground state indicates that ammonia–metal interactions are dominated by the energy delocalization term. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 213–219, 2001
Electron structure of polysilanes. Are these polymers one‐dimensional systems?
Authors: Pelikán P. , Košuth M. , Biskupič S. , Noga J. , Straka M. , Zajac A. , Baňacký P.
Published: August 2002

Electron structures of polysilane, 1‐methyl polysilane, 1,1‐dimethyl polysilane, 1‐phenyl polysilane, 1,1‐diphenyl polysilane, and 1‐methyl 1‐phenyl polysilane in solid state were calculated using the cyclic cluster orbital method (CCO), based on a Hartree–Fock approach using a quasirelativistic INDO Hamiltonian applied to cyclic clusters. Effect of the redistribution of electron density on the silicon backbone chains after the substitution of hydrogen by methyl and phenyl groups has been investigated. Going from one‐ to three‐dimensional models, significant changes appear in calculated electron distributions, as well as in the band structure topologies of the corresponding polymers. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 157–168, 2001
meta and para substitution effects on the electronic state energies and ring‐expansion reactivities of phenylnitrenes
Authors: Johnson William T. G. , Sullivan Michael B. , Cramer Christopher J.
Published: August 2002

The electronic structures of the triplet ground states and first three excited singlet states for phenylnitrene, 14 meta‐, and 17 para‐substituted congeners have been characterized using density functional theory and multireference second‐order perturbation theory (CASPT2). Ring expansion pathways to form didehydroazepines have activation enthalpies of about 9 kcal⋅mol−1 and are fairly insensitive to substitution—in the case of the strongest para donor, MeNH–, this barrier increases to about 13 kcal⋅mol−1. The trends in state energies as a function of substitution are rationalized using a (2,2) configuration interaction theory and qualitative molecular orbital theory. Analysis of spin‐orbit coupling in the nitrenes using the same model in conjunction with explicit calculation of spin‐orbit coupling matrix elements rationalizes why electron donating substituents increase rates of intersystem crossing. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Theory and applications of the integrated molecular transform and the normalized molecular moment structure descriptors: QSAR and QSPR paradigms
Authors: Molnar Stephen P. , King James W.
Published: August 2002

The chemical and mathematical rationalé in the development of the numerically unitary integrated molecular transform (FTm), its analogous electronic (FTe) and charge (FTc) transforms, and the normalized molecular moment (Mn), and its analogous electronic (Me) and charge (Mc) moment as molecular structure descriptors are presented. The reported application and utilization of these indices for predictive capability correlations of structure with physicochemical, pharmacological, and thermodynamic properties are reviewed. The further use of these descriptors in considerations of chemical similarity is noted, as is their capability for searching compound databases whose contents include the noted calculated indices. Their potential for characterizing peptides, proteins, and oligomers as well as their possible function in mathematical models is discussed. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Experimentation with different thermodynamic cycles used for pKa calculations on carboxylic acids using complete basis set and Gaussian‐n models combined with CPCM continuum solvation methods
Authors: Liptak Matthew D. , Shields George C.
Published: August 2002

Complete basis set and Gaussian‐n methods were combined with Barone and Cossi's implementation of the polarizable conductor model (CPCM) continuum solvation methods to calculate pKa values for six carboxylic acids. Four different thermodynamic cycles were considered in this work. An experimental value of −264.61 kcal/mol for the free energy of solvation of H+, ΔGs(H+), was combined with a value for Ggas(H+) of −6.28 kcal/mol, to calculate pKa values with cycle 1. The complete basis set gas‐phase methods used to calculate gas‐phase free energies are very accurate, with mean unsigned errors of 0.3 kcal/mol and standard deviations of 0.4 kcal/mol. The CPCM solvation calculations used to calculate condensed‐phase free energies are slightly less accurate than the gas‐phase models, and the best method has a mean unsigned error and standard deviation of 0.4 and 0.5 kcal/mol, respectively. Thermodynamic cycles that include an explicit water in the cycle are not accurate when the free energy of solvation of a water molecule is used, but appear to become accurate when the experimental free energy of vaporization of water is used. This apparent improvement is an artifact of the standard state used in the calculation. Geometry relaxation in solution does not improve the results when using these later cycles. The use of cycle 1 and the complete basis set models combined with the CPCM solvation methods yielded pKa values accurate to less than half a pKa unit. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001