bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of poly(lactide‐ran‐MOHEL) and its biodegradation with proteinase K
Authors: Shirahama Hiroyuki , Mizuma Kiyoshi , Umemoto Koichi , Yasuda Hajime
Published: August 2002

Homopoly(L‐lactide) and homopoly(D,L‐lactide) were almost inert for biodegradation with tricine buffer or normal enzymes such as bromelain, pronase, and cholesterol esterase but biodegradable with proteinase K. Significantly enhanced biodegradation was observed when an optically active (R)‐ or (S)‐3‐methyl‐4‐oxa‐6‐hexanolide (MOHEL) unit was introduced into poly(L‐lactide) [poly(L‐LA)] or poly(D,L‐lactide) [poly(D,L‐LA)] sequences. Poly[L‐LA‐ran‐(R)‐MOHEL] in molar ratios of 86/14 to 43/57 showed good biodegradability that was independent of crystallinity. The biodegradation of polymers with proteinase K increased in the following order: poly[D,L‐LA‐ran‐(R)‐MOHEL] > poly[L‐LA‐ran‐(R)‐MOHEL] > poly[D,L‐LA‐ran‐(S)‐MOHEL] > poly[L‐LA‐ran‐(S)‐MOHEL] > poly(R)‐MOHEL > poly(D,L‐LA). The number‐average molecular weight, molecular weight distribution, glass‐transition temperature, and melting temperature did not change before and after the biodegradation of poly[L‐LA‐ran‐(R)‐MOHEL], indicating that the degradation occurred from the polymer surface. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1374–1381, 2001
Enhanced dissolution of copolymers bearing photobase‐ or photoacid‐generating groups in polar solvents by photochemical formation of ionic pairs
Authors: Suyama Kanji , Yamaguchi Shizue , Shirai Masamitsu , Tsunooka Masahiro
Published: August 2002

Solubility changes in the irradiation of copolymers bearing photoacid‐ or photobase‐generating groups and low molecular weight photobase generators (PBGs) or photoacid generators (PAGs) were investigated. Copolymers bearing acyloxyimino (AOI) groups were used as those generating pendant amino groups photochemically. Copolymers bearing o‐nitrobenzyloxycarbonyl and imino sulfonate groups were used as those generating carboxy and sulfo groups, respectively. The solubility of copolymers bearing AOI groups into polar solvents was enhanced by added PAGs such as β‐keto sulfones or imino sulfonates after irradiation. A similar enhancement was observed in copolymers bearing o‐nitrobenzyloxycarbonyl groups in the presence of PBGs such as oxime esters or o‐nitrobenzyl carbamates. These results showed that the formation of acid–base pairs on irradiation was effective for dissolution into polar solvents. Copolymers bearing imino sulfonate groups showed a high solubility, and no such enhancement was observed by PBG. Films of copolymers bearing β‐keto sulfone groups became insoluble because of crosslinking. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1708–1715, 2001
Fast and convenient construction of carbamate/urea‐based dendrimers with a diisocyanate building block
Authors: Peerlings H. W. I. , Van Benthem R. A. T. M. , Meijer E. W.
Published: August 2002

A novel, fast, and simple synthetic procedure for polycarbamate/urea dendrimers, based on an AB–CD2 coupling strategy, is presented. The reactivity difference of the two isocyanate functionalities of the AB building block allows the construction of these dendrimers without the necessity of activation or deprotection steps. This makes it possible to construct dendrimers within 2–3 days, even the largest dendrimers. The resulting dendrimers could be fully characterized by 13C NMR, IR spectroscopy, and mass spectrometry. The synthetic strategy necessitates only techniques such as stirring, heating, and accurate dosing, and there is no workup required for the purification of the compounds. On account of a wide variety of polyols, amines, and aminoalcohols, this new procedure is not limited to the synthetic strategy followed but allows the incorporation of a large variety of functional molecules in the core, in the branching units, or at the end groups. The method is even applicable when organometallic species are incorporated into the dendritic structure, thereby showing its versatility. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3112–3120, 2001
Conformational contribution to the heat capacity of the starch and water system
Authors: Pyda Marek
Published: August 2002

The heat capacities of starch and starch—water have been measured with adiabatic calorimetry and standard differential scanning calorimetry and are reported from 8 to 490 K. The amorphous starch containing 11–26 wt % (53–76 mol %) water shows a partial glass transition decreasing from 372 to 270 K, respectively. Even the dry amorphous starch gradually increases in heat capacity above 270 K beyond that set by the vibrational density of states. This gradual increase in the heat capacity is identified as part of the glass transition of dry starch that is, however, not completed at the decomposition temperature. The heat capacities of the glassy, dry starch are linked to an approximate group vibrational spectrum with 44 degrees of freedom. The Tarasov equation is used to estimate the heat capacity contribution due to skeletal vibrations with the parameters Θ1 = 795.5 K, Θ2 = 159 K, and Θ3 = 58 K for 19 degrees of freedom. The calculated and experimental heat capacities agree better than ±3% between 8 and 250 K. Similarly, the vibrational heat capacity has been estimated for glassy water by being linked to an approximate group vibrational spectrum and the Tarasov equation (Θ1 = 1105.5 K and Θ3 = 72.4 K, with 6 degrees of freedom). Below the glass transition, the heat capacity of the solid starch—water system has been estimated from the appropriate sum of its components and also from a direct fitting to skeletal vibrations. Above the glass transition, the differences are interpreted as contributions of different conformational heat capacities from chains of the carbohydrates interacting with water. The conformational parts are estimated from the experimental heat capacities of dry starch and starch—water, decreased by the vibrational and external contributions to the heat capacity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 3038–3054, 2001
Nonisothermal crystallization kinetics of polypropylene/montmorillonite nanocomposites
Authors: Xu Weibing , Ge Mingliang , He Pingsheng
Published: August 2002

The nonisothermal crystallization kinetics of poly(propylene) (PP) and poly(propylene)/organic‐montmorillonite (PP/Mont) nanocomposite were investigated by differential scanning calorimetry (DSC) with various cooling rates. The Avrami analysis modified by previous research was used to describe the nonisothermal crystallization process of PP and PP/Mont nanocomposite very well. The values of half‐time and Zc showed that the crystallization rate increased with increasing cooling rates for both PP and PP/Mont nanocomposite, but the crystallization rate of PP/Mont nanocomposite was faster than that of PP at a given cooling rate. The activation energies were estimated by the Kissinger method, and the values were 189.4 and 155.7 kJ/mol for PP and PP/Mont nanocomposite, respectively. PP/Mont nanocomposite could be easily fabricated as original PP, although the addition of organomontmorillonite might accelerate the overall nonisothermal crystallization process. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 408–414, 2002; DOI 10.1002/polb.10101
Stress distribution in poly‐p‐phenylenebenzobisoxazole (PBO) fiber as viewed from vibrational spectroscopic measurement under tension. I. Stress‐induced frequency shifts of Raman bands and molecular deformation mechanism
Authors: Kitagawa Tooru , Tashiro Kohji , Yabuki Kazuyuki
Published: August 2002

To clarify the relationship between a molecular deformation mechanism and a high Young's modulus of poly‐p‐phenylenebenzobisoxazole (PBO), Raman spectra were measured for fibers subjected to a tensile stress along the chain axis. The stress‐induced frequency shift of the observed Raman bands could be reproduced reasonably by the normal‐mode calculation under a quasi‐harmonic approximation. The frequency position at zero stress and the shift factor of Raman bands were predicted for a PBO chain that agreed with the actually evaluated values. On the basis of these analyses, the molecular deformation mechanism of the PBO chain has been discussed in detail. The crystalline modulus of the PBO chain was calculated theoretically to be 458 GPa, in good agreement with the X‐ray observed value of 460 GPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1269–1280, 2002
Degradation of polymer coating systems studied by positron annihilation spectroscopy. IV. Oxygen effect of UV irradiation
Authors: Zhang R. , Chen H. , Cao H. , Huang C.‐M. , Mallon P. E. , Li Y. , He Y. , Sandreczki T. C. , Jean Y. C. , Suzuki R. , Ohdaira T.
Published: August 2002

The effect of oxygen on the photodegradation of a polyurethane coating induced by accelerated UV irradiation was studied with two different light sources: 313‐nm UVB and Xe lamps. Doppler‐broadened energy spectra (DBES) and positron annihilation lifetimes were measured as a function of incident positron energy (0–30 keV) and irradiation time (0–100 h). The photodegradation of the coating was characterized in terms of subnanometer defect changes. Significant variations of the S parameter (a defect parameter from DBES) and the ortho‐positronium lifetime and intensity were observed as a function of oxygen concentration during exposure to UV irradiation. These results showed a significant enhancement in photodegradation due to the presence of oxygen, as indicated by a decrease in free volume and holes at the atomic level. Enhanced degradation in the presence of oxygen, as indicated by increased free‐radical production (observed with electron spin resonance spectroscopy), was also observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2035–2047, 2001
Shared decision‐making in question
Authors: Charavel Marie , Bremond Alain , Moumjid‐Ferdjaoui Nora , Mignotte Herve , Carrere Marie Odile
Published: August 2002

Over recent years, communication within the physician–patient relationship has been profoundly changing. New modes of conveying diagnostic and therapeutic information influence the way in which decisions regarding treatment are made. We propose a critical review of the various theoretical models as presented in the literature, from the paternalistic to the shared decision model, in order to reveal conceptual ambiguities and their related methodological problems. This analysis leads to a project for clarifying these problems through a research protocol based on shared decision‐making. Copyright © 2001 John Wiley & Sons, Ltd.
The eortc QLQ‐C30 (version 3.0) quality of life questionnaire: validation study for Spain with head and neck cancer patients
Authors: Arraras J.I. , Arias F. , Tejedor M. , Pruja E. , Marcos M. , Martínez E. , Valerdi J.
Published: August 2002

The EORTC Quality of Life Study Group has developed a questionnaire for evaluating Quality of Life in international clinical trials: QLQ‐C30. The purpose of the present work is to validate the third version of this questionnaire (3.0) for use in Spain.

Two hundred and one head and neck cancer patients completed the QLQ‐C30 at one or two time points during the treatment and follow‐up periods, and a subsample completed the questionnaire on three occasions. Psychometric evaluation of the structure, reliability and validity of the questionnaire was undertaken.

The data support the structure and the reliability of the scales. Validity was confirmed in three ways: the interscale correlations are statistically significant and moderate, several scales and items discriminate among groups of patients with different scores on the clinical variables, and some scales reflect significant changes during treatment and the follow‐up period.

The EORTC QLQ‐C30 (version 3.0) is a reliable and valid questionnaire when applied to a sample of Spanish head and neck cancer patients. These results are in line with previous studies. Copyright © 2002 John Wiley & Sons, Ltd.
Glacial and periglacial phenomena in Ethiopia: a review
Authors: Grab Stefan
Published: August 2002

The glacial and periglacial geomorphology for the Simen and Bale Mountains in Ethiopia is reviewed. The Simen Mountains are mostly absent of relict periglacial landforms and today host a variety of miniature cryogenic phenomena. The Bale Mountains host a few localized large relict cryogenic landforms (e.g. stone stripes), suggesting past sporadic permafrost. A variety of regional factors may have contributed to the more extensive periglacial activity in southern Ethiopia than in the higher Simen Mountains to the north. Copyright © 2002 John Wiley & Sons, Ltd.
Benefits of thickened feeds in previously healthy infants with respiratory syncytial viral bronchiolitis
Authors: Khoshoo Vikram , Ross Gerald , Kelly Beth , Edell Dean , Brown Shannan
Published: August 2002

Infants with respiratory syncytial virus (RSV) bronchiolitis have an increased risk of aspiration. The optimal feeding strategy for these patients has not been described. Fifteen previously healthy and clinically stable infants with RSV bronchiolitis underwent video‐fluoroscopy studies to assess swallowing using thin barium. Those with abnormal studies underwent a repeat study, using barium that was thickened with rice cereal.

Nine of 15 infants had abnormal studies with thin barium. Laryngeal or tracheal penetration with thin barium was seen in 3 and 2 infants, respectively, but not with thickened barium. Aspiration of thin barium was seen in 4 infants, but it corrected in 3 of these 4 infants with thickened barium.

Thickened feeds provide a simple, safe, and cost‐effective intervention to improve swallowing dysfunction and prevent aspiration in infants with RSV bronchiolitis. Pediatr Pulmonol. 2001; 31:301–302. © 2001 Wiley‐Liss, Inc.
Bronchoscopic instillation of surfactant in acute respiratory distress syndrome
Authors: Nakamura Craig T. , Ripka James F. , McVeigh Karen , Kapoor Neena , Keens Thomas G.
Published: August 2002

Abnormalities of surfactant action in acute respiratory distress syndrome (ARDS) result in decreased lung compliance and significant hypoxemia. Several case reports and small studies suggest that there is an improvement in patients with ARDS following the administration of surfactant. However, there is no clear‐cut ideal method for surfactant administration. The bronchoscopic administration of surfactant may represent an effective method of surfactant delivery in ARDS. Bronchoscopic instillation offers the theoretical advantages that the surfactant may be distributed directly to the desired regions of the lung, a more economical use of surfactant, and the opportunity to lavage leaked serum proteins prior to instillation. Surfactant has been administered in adults with success. We present a case of initial improvement in oxygenation index, ventilation index, and mechanical ventilatory support in a pediatric patient with ARDS following the bronchoscopic administration of surfactant. Pediatr Pulmonol. 2001; 31:317–320. © 2001 Wiley‐Liss, Inc.
Reduction of oscillatory pressure along the endotracheal tube is indicative for maximal respiratory compliance during high‐frequency oscillatory ventilation: A mathematical model study
Authors: van Genderingen H.R. , Versprille A. , Leenhoven T. , Markhorst D.G. , van Vught A.J. , Heethaar R.M.
Published: August 2002

We hypothesized that during high‐frequency oscillatory ventilation (HFOV), a reduction of peak‐to‐peak oscillatory pressure along the endotracheal tube is maximal when respiratory system compliance is maximal. We made a mathematical model of the endotracheal tube and the respiratory system of a neonate suffering from idiopathic respiratory distress syndrome (IRDS). The model consisted of linear viscous and inertive elements, a non‐linear endotracheal tube resistance, and a non‐linear compliance allowing for alveolar recruitment and overdistention. Respiratory compliance was maximal at the transition between maximal recruitment and minimal overdistention. A new variable, the oscillatory pressure ratio (OPR), was defined as the ratio between peak‐to‐peak oscillatory pressures at the distal end and the proximal opening of the endotracheal tube, respectively. The respiratory variables of four patients were fed into the model, and the relationship between respiratory system compliance and OPR was determined.

OPR decreased as compliance increased, except for very low compliances below where 0.08 mL · cmH2O−1, and OPR increased with increasing compliance. The relationship between mean airway pressure P̄aw and OPR revealed that the minimal OPR (range, 0.37–0.78) and maximal respiratory compliance coincided at the same P̄aw. However, the relationship did depend on oscillation frequency, applied oscillatory pressure, and endotracheal tube resistance, parameters that may change during clinical application of HFOV. When 81 permutations of nominal and extreme respiratory variables were used in the model, the minimum OPR (0.60 ± 0.23) and maximum compliance coincided in all cases.

These model experiments support our hypothesis. The results indicate that the OPR may be a useful index to optimize lung expansion, where lung recruitment is maximal and overdistention minimal. In vivo tests will be needed to reveal the feasibility and reliability of such an index for biomedical and clinical application. Pediatr Pulmonol. 2001; 31:458–463. © 2001 Wiley‐Liss, Inc.
Effects of fetal growth restriction on lung development before and after birth: A morphometric analysis
Authors: Maritz G.S. , Cock M.L. , Louey S. , Joyce B.J. , Albuquerque C.A. , Harding R.
Published: August 2002

Our aim was to determine the effects of fetal growth restriction (FGR) during late gestation on the structure of the lungs in the fetus near term and at 8 weeks after birth. The studies were performed using two groups of pregnant sheep and their offspring. In both groups, FGR was induced by umbilico‐placental embolisation (UPE); for fetal studies, UPE was performed from 120 days of gestation until 140 days (term, ∼146 days), when fetuses were killed for tissue analysis. For postnatal studies, UPE continued from 120 days until delivery at term; postnatal lambs were killed at 8 weeks after birth for tissue analysis.

UPE led to a thicker pulmonary blood‐air barrier at 140 days of gestation and this difference, which was due to a thickened basement membrane, was still present at 8 weeks after birth. At 8 weeks, we also observed a smaller number of alveoli per respiratory unit, thicker interalveolar septa, and a greater volume density of lung tissue in FGR lambs compared to controls. These changes would be expected to impair gas exchange and alter the mechanical properties of the lungs.

Our data show that structural alterations in the lungs induced by placental insufficiency were more evident at 8 weeks of postnatal age than near term, indicating that the effects of FGR on the lung may become more serious with age and may affect respiratory health later in life. Pediatr Pulmonol. 2001; 32:201–210. © 2001 Wiley‐Liss, Inc.
Multiple protein folding nuclei and the transition state ensemble in two‐state proteins
Authors: Klimov D.K. , Thirumalai D.
Published: August 2002

Using exhaustive simulations of lattice models with side‐chains, we show that optimized two‐state folders reach the native state by a nucleation‐collapse mechanism with multiple folding nuclei (MFN). For both the full model and the Go version, there are certain contacts that on an average participate in the critical nuclei with higher probability than the others. The high‐ (≳0.5) probability contacts are largely determined by the structure of the native state. Comparison of the results for the full sequence and the Go model shows that non‐native interactions compromise the degree of cooperativity and stability of the native state. From an extremely detailed analysis of the folding kinetics, we find that non‐native interactions are present in the folding nuclei. The folding times decrease if the non‐native interactions in the folding nuclei are made neutral or repulsive. Using cluster analysis and making no prior assumption about reaction coordinate, we show that both full and Go models have three distinct transition states that give a structural description for the MFN. In the transition states, on an average, about two‐thirds of the sequence is structured, whereas the rest is disordered, reminiscent of the polarized transition state in the SH3 domain. Our studies show that Go models cannot describe the transition state characteristics of two‐state folders at the molecular level. As a byproduct of our investigations, we establish that our method of computing the transition state ensemble is numerically equivalent to the technique based on the stochastic separatrix, which also does not require a priori knowledge of the folding reaction coordinate. Proteins 2001;43:465–475. © 2001 Wiley‐Liss, Inc.
The insecticide target in the PSST subunit of complex I
Authors: Schuler Franz , Casida John E
Published: August 2002

Current insecticides have been selected by sifting and winnowing hundreds of thousands of synthetic chemicals and natural products to obtain commercial preparations of optimal effectiveness and safety. This process has often ended up with compounds of high potency as inhibitors of the electron transport chain and more specifically of complex I (NADH:ubiquinone oxidoreductase). Many classes of chemicals are involved and the enzyme is one of the most complicated known, with 43 subunits catalyzing electron transfer from NADH to ubiquinone through flavin mononucleotide and up to eight iron–sulfur clusters. We used a potent photoaffinity ligand, (trifluoromethyl)diazirinyl‐[3H]pyridaben, to localize the insecticide target to a single high‐affinity site in the PSST subunit that couples electron transfer from iron–sulfur cluster N2 to ubiquinone. Most importantly, all of the potent complex I‐inhibiting pesticides, despite their great structural diversity, compete for this same specific binding domain in PSST. Finding their common mode of action and target provides insight into shared toxicological features and potential selection for resistant pests.

© 2001 Society of Chemical Industry
Molluscicidal and anti‐feedant activities of diterpenes from Euphorbia paralias L
Authors: Abdelgaleil Samir A M , El‐Aswad Ahmed F , Nakatani Munehiro
Published: August 2002

Nine known diterpene polyesters of segetanes, jatrophenes and paralianes have been isolated from the aerial parts of Euphorbia paralias L. The molluscicidal activity of isolated compounds was evaluated on Biomphalaria alexandrina (Ehrenberg). Paraliane diterpene, (2S,3S,4R,5R,6R,8R, 12S,13S,14R,15R)‐5,8,14‐triacetoxy‐3‐benzoyloxy‐15‐hydroxy‐9‐oxo‐paraliane, was the most potent compound against the snail. Anti‐feedant activity was tested by a conventional leaf disc method against third‐instar larvae of Spodoptera littoralis (Boisd). Jatrophene diterpene, (2R,3R,4S,5R,7S,8R,13R, 15R)‐2,3,5,7,15‐pentaacetoxy‐8‐angeloyloxy‐14,15‐dioxojatropha‐6(17)‐11E‐diene, had the highest anti‐feedant activity among the compounds tested.

© 2002 Society of Chemical Industry
Ship structural safety and reliability
Authors: Paik J K , Frieze P A
Published: August 2002

Recent research and development in the area of design methodologies related to safety and reliability of ship structures is reviewed, focusing on some relevant probabilistic approaches used for the load and resistance factor design (LRFD) of ship hulls against collapse. Important insights and findings previously obtained in the literature are summarized, and recommendations are made with respect to both technologically improved design procedures and those needed for future development.
Augmentation of natural killer cell activity in vivo against tumour cells by some wild plants from Jordan
Authors: Abuharfeil N. M. , Salim Maher , Von Kleist S.
Published: August 2002

Twelve aqueous extracts prepared from Jordanian plants that are currently used in traditional medicine to treat various types of cancer were tested in mice for their augmentation of natural killer cells in vivo in generating cytotoxicity against YAC tumour targets. After 1 week of oral administration of aqueous extracts of fresh Nigella sativum (N.s.) seeds and Allium sativum (A.s.) bulbs significant augmentation of splenic natural killer (NK) cells (62.3% ± 6.4% and 52.6% ±5.4% cytotoxicity, respectively), was obtained in comparison with spontaneous activity (24.5% ± 1.6%) at 200:1 effector:target ratio. Onopordum acanthium (O.a.) stem and leaves and Allium cepa (A.c.) bulbs showed intermediate augmentation (38.6% ± 3.8% and 30.6% ± 3.4% cytotoxicity, respectively) while the rest showed insignificant augmentation activity. The fresh aqueous extract of a mixture of the plants with high and intermediate activity showed little insignificant augmentation activity (72.7% ± 6.7% cytotoxicity) of NK cells compared with that obtained with each plant alone. Copyright © 2001 John Wiley & Sons, Ltd.
Analgesic and antiinflammatory activities of vernonioside B2 from Vernonia condensata
Authors: Valverde A. L. , Cardoso G. L. C. , Pereira N. A. , Silva A. J. R. , Kuster R. M.
Published: August 2002

Vernonioside B2 isolated from the methanol extract of the Brazilian herb Vernonia condensata Baker was evaluated in vivo for analgesic and antiinflammatory activities. The compound reduced writhings (93.28%) and Evans blue dye diffusion (91.80%) induced by acetic acid (0.1 N) in a dose‐dependent manner. Copyright © 2001 John Wiley & Sons, Ltd.
The first clinical trial of topical application of procyanidin B‐2 to investigate its potential as a hair growing agent
Authors: Takahashi Tomoya , Kamimura Ayako , Yokoo Yoshiharu , Honda Shinkichi , Watanabe Yasushi
Published: August 2002

Procyanidin B‐2 is a compound we have identified in apple which acts as a growth‐promoting factor on murine hair epithelial cells. This report describes our investigation of the hair‐growing effects of 1% procyanidin B‐2 tonic after sequential use for 4 months. A double‐blind clinical trial was performed, involving a total of 29 subjects (procyanidin B‐2, 19 men; placebo, 10 men). No adverse side effects were observed in either group. In the procyanidin B‐2 group, 78.9% showed an increased mean value of hair diameter, whereas only 30.0% in the placebo group showed any increase (p < 0.02, Fisher's exact probability test). The increased ratio of hairs measuring more than 40 μm in diameter after 4 months of procyanidin B‐2 treatment was significantly higher than that of the placebo controls (p < 0.05, two‐sample­t‐test). The increase in number of total hairs in the designated scalp area (0.25 cm2) of procyanidin B‐2 subjects after a 4 month trial was significantly greater than that of the placebo controls (procyanidin­B‐2, 3.67 ± 4.09 (mean ± SD)/0.25 cm2; placebo, −2.54 ± 4.00/0.25 cm2; p < 0.001, two‐sample t‐test). Procyanidin B‐2 therapy shows potential as a promising cure for male pattern baldness. Copyright © 2001 John Wiley & Sons, Ltd.
Morphologic and morphometric analyses of acetic acid‐induced colitis in rats after treatment with enemas from Myracrodruon urundeuva Fr. All. (Aroeira do Sertão)
Authors: Rodrigues Lusmar Veras , Ferreira Francisco Valdeci , Regadas F. Sérgio P. , Matos Délcio , Viana Glauce Socorro de Barros
Published: August 2002

The present work showed the effects of Myracrodruon urundeuva Fr. All., popularly known as ‘aroeira’ (AE), in the form of enemas prepared from the stem bark, on several morphologic and morphometric parameters after acetic acid‐induced colitis in rats. Enemas from 5‐ASA were used as standard while the vehicle, carboxymethylcellulose, was used as a control. The results of the morphological evaluation showed that on day 1 acetic acid produced significantly more necrosis in the groups treated with AE (10% and 20%) or 5‐ASA than the controls. However, on day 60, there were more caliciform and absorptive cells in the treated groups compared with the controls. A significantly higher number of eosinophil and mononuclear cells and also collagen deposition in the controls compared with the treated groups were observed on day 60. However, a higher number of polymorphonuclear cells was detected on day 60 only in the AE treated group but not in the 5‐ASA group. These data indicate that animals treated with AE or 5‐ASA showed complete epithelial tissue regeneration, while in the controls chronic inflammatory exudate persisted and tissue regeneration occurred through fibrosis. Copyright © 2002 John Wiley & Sons, Ltd.
Phytochemical and antioedematogenic studies of commercial copaiba oils available in Brazil
Authors: Veiga Valdir F. , Zunino Luciano , Calixto João B. , Patitucci Maria L. , Pinto Ângelo C.
Published: August 2002

The composition of eight samples of commercial copaiba oils, used in the Amazonian region as antiinflammatory agents and available in popular markets, were analysed by gas chromatography/mass spectrometry (HRGC‐MS). Major differences were observed in their chemical composition and some adulterations were pointed out. When tested in vivo oils 1 and 3, and to a lesser extent oil 6, significantly inhibited bradykinin‐induced oedema formation. The other tested oils had no effect. When assessed in carrageenan‐induced oedema formation, oils 1, 2 and 6, but not oil 3, significantly attenuated the oedema formation. The other tested oils failed to affect carrageenan‐induced paw oedema. Oils 1 and 6 were further fractionated and several sesquiterpenes and diterpenes were detected. It is suggested that the naturally occurring sesquiterpenes present in the copaiba oils seem to be responsible for the antiinflammatory action reported in the folk medicine. Furthermore, our results clearly show an adulteration in copaiba oils available in Brazil. Copyright © 2001 John Wiley & Sons, Ltd.
Odorous compounds in paperboard as influenced by recycled material and storage
Authors: Ziegleder Gottfried
Published: August 2002

Many volatile compounds can be identified in unprinted paperboard by means of steam distillation in combination with capillary gas chromatography, mass spectrometry and olfactometry. Paperboards produced with recycled material exhibit additional volatiles which partly contribute to off‐odours. Using sniffing techniques, benzaldehyde, acetophenone, 1‐octen‐3‐ol, 1‐octen‐3‐one, 2‐nonenal, methylguajacol, butanoic and 3‐methyl butanoic acid were identified as the most odorous volatiles. The aromatic substances mainly exude from inks and printing solvents in waste materials used for paperboard manufacturing. During storage under controlled conditions, the microbial load of paperboard decreased slightly, and no odorous metabolic products were generated. Copyright © 2001 John Wiley & Sons, Ltd.
A constraint‐based approach to the modelling and analysis of packaging machinery
Authors: Hicks B. J. , Medland A. J. , Mullineux G.
Published: August 2002

To enable packaging machinery manufacturers to compete at an international level, it is necessary to introduce them to more advanced design methods and technologies. For years, the evolution of packaging machinery has relied heavily on trial‐and‐error methods. The demands for continual increases in the performance capabilities of the machines, escalating legislation, environmental directives and changes in the characteristics of the product require rapid development of existing machine designs and the creation of new machines. This paper discusses the needs of SME packaging machinery manufacturers and identifies their requirements for methods in support of the design and redesign of packaging machinery. The need to identify, capture and manipulate design knowledge is critical for SMEs, where all too often design records are incomplete. Furthermore, a systems modelling approach that provides for support over the conceptual, embodiment and detailed design phases is essential for the rapid and effective development of designs. In order to meet these requirements, a methodology is proposed which incorporates ‘constraint modelling’ techniques. The methodology provides for experimental investigation and computer‐based modelling, which together aid the designer in gaining a fundamental understanding of the design problem. This enables the identification and representation of design knowledge, the determination of the limitations of an existing design, the evaluation of alternative designs and redesign strategies, as well as the embodiment, refinement and optimization of design solutions. The theory of ‘constraint modelling’ is discussed and the various phases of the methodology described. The applications of the methodology to a new machine design and a redesign program are also detailed. Copyright © 2001 John Wiley & Sons, Ltd.
Robustness of Chi‐square and Canberra distance metrics for computer intrusion detection
Authors: Emran Syed Masum , Ye Nong
Published: August 2002

Intrusion detection complements intrusion prevention mechanisms, such as firewalls, cryptography, and authentication, to capture intrusions into an information system while they are acting on the information system. We develop two multivariate quality control techniques based on chi‐square and Canberra distance metrics, respectively, to detect intrusions by building a long‐term profile of normal activities in the information system (norm profile) and using the norm profile to detect anomalies. We investigate the robustness of these two distance metrics by comparing their performance on a number of data sets involving different noise levels in data. The performance results indicate that the Chi‐square distance metric is much more robust to noises than the Canberra distance metric. Copyright © 2002 John Wiley & Sons, Ltd.
Protein interaction property similarity analysis
Authors: Wade R. C. , Gabdoulline R. R. , De Rienzo F.
Published: August 2002

We describe how similarity indices may be applied to semiquantitatively compare the molecular interaction fields, such as electrostatic and hydrophobic potentials, of proteins. We then review ways in which this approach has been used to investigate protein interaction properties in diverse applications ranging from in‐depth comparison of pairs of proteins to large‐scale analysis of hundreds of modeled protein structures. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 122–127, 2001
Modeling zinc sulfhydryl bonds in zinc fingers
Authors: Bredenberg Johan , Nilsson Lennart
Published: August 2002

Molecular dynamics simulations have been carried out employing three different model descriptions of the zinc sulfhydryl interactions in class II fingers. One bonded and two nonbonded models were studied. Two variant structures of the glucocorticoid receptor DNA‐binding domain and a NMR structure from a fragment of methionyl‐tRNA synthetase were subjected to long‐time MD simulations with these models. Our analysis is focused on comparison with experimental and quantum mechanical data, concerning the local Zn‐finger and overall structural and dynamic properties for these models. All models performed well, but the nonbonded models appeared to reproduce the protein dynamics in better agreement with experimental data than does the bonded description. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 230–244, 2001
Theoretical studies on the spectroscopy of the 7‐azaindole monomer and dimer
Authors: Serrano‐Andrés Luis , Merchán Manuela , Borin Antonio Carlos , Stålring Jonna
Published: August 2002

The absorption and the emission spectra, both fluorescence and phosphorescence, of the 7‐azaindole molecule have been studied by means of the complete active space (CAS) SCF method and multiconfigurational second‐order perturbation theory (CASPT2). Excitation energies, oscillator strengths, dipole moments, transition dipole moments, and their directions have been computed and the results compared to those of analogous molecules such as indene, indole, and benzimidazole, to get a homogeneous picture of the photophysics of the systems. The absorption and emission of the 7‐azaindole dimer and its related tautomer have also been computed in order to get further insight into the double fluorescence phenomenon, which was first observed in highly concentrated media. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 181–191, 2001
Characterization of dehydroascorbic acid solutions by liquid chromatography/mass spectrometry
Authors: Pastore Paolo , Rizzetto Tania , Curcuruto Ornella , Cin Michele Dal , Zaramella Alessio , Marton Daniele
Published: August 2002

The composition of a commercial dehydroascorbic acid (DA) solution at pH 2 was investigated by liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) to establish the nature of its different forms and its decomposition products. In freshly prepared solutions, dimeric forms of DA and the hydrated bicyclic hemiketal of DA are the species mainly present in solution. In the presence of light, the initial dimeric species disappears over time to give other dehydrated dimers some of which decompose to the monomer. The comparison of these data with similar data obtained for ascorbic acid (AA) solutions under the same experimental conditions revealed that, in the presence of light, the aging of such AA solutions gives rise to only the hemiketal form of DA, and that no dimeric species of DA were formed. The presence of the hemiketal form of DA was not revealed by analysis of the same AA solutions using the conventional LC/UV technique. The natural form of DA from the oxidation of AA is the hydrated bicyclic form. Copyright © 2001 John Wiley & Sons, Ltd.
Implications of matrix effects in ultra‐fast gradient or fast isocratic liquid chromatography with mass spectrometry in drug discovery
Authors: Tiller Philip R. , Romanyshyn Leslie A.
Published: August 2002

In the analysis of biological samples it is important to reduce the risk of interferences from the matrix itself, other analytes, the dosing vehicle (commonly PEG), and from the MS/MS transitions used for the analysis. Rapid analysis is essential for drug discovery, and even though the requirements for separation may be minimized for speed, the integrity of the analysis is still dependent on the separation. This paper focuses on the potential for interferences from various endogenous and exogenous matrix components commonly encountered in quantitation of analytes and their metabolites from biological matrices. We demonstrate that neither high organic isocratic nor ballistic gradient ultra‐fast HPLC show a clearly defined advantage in regards to complex biological matrices. The critical factor in the resolution of matrix interferences still remains in sample preparation. Copyright © 2001 John Wiley & Sons, Ltd.
The pathogenesis of febrile seizures: Is there a role for specific infections?
Authors: van Zeijl J.H. , Mullaart R.A. , Galama J.M.D.
Published: August 2002

Although fever is regarded as the main trigger in the pathogenesis of febrile seizures (FS), it is not supposed to be the unique causative factor. In FS, there is a strong familial predisposition. This does not exclude infections as a causative factor because subtle genetic polymorphisms have been demonstrated to affect the course of infections. We review the literature on: (1) the role of fever, especially the height of temperature, its cause, and metabolic effects induced by temperature; (2) the role of heredity; (3) the role of cytokines which play a role in the induction of fever; and (4) the role of type of infection, with emphasis on newly identified agents and improved diagnostic techniques. With modern molecular techniques such as PCR, viruses have been detected in the CSF far more often than previously thought, even in the absence of pleocytosis of the CSF. This makes it difficult to distinguish FS from acute encephalitis. FS may be caused by neuroinvasion or intracerebral activation of viruses. Further studies should focus on these options because therapeutic intervention is possible and may prevent late sequelae such as recurrent FS and subsequent epilepsy. Copyright © 2002 John Wiley & Sons, Ltd.
Chattering‐free sliding mode control for a class of nonlinear mechanical systems
Authors: Parra‐Vega Vicente , Hirzinger Gerd
Published: August 2002

Second‐order sliding mode control (2‐smc) and dynamic sliding mode control (dsmc) eliminate the disturbing characteristic of chattering in static sliding mode control under the assumption that the derivative of the sliding surface is available or complex inequalities at the acceleration level can be constructed. In this paper, passivity‐based adaptive and non‐adaptive chattering‐free sliding mode controllers are proposed assuming that the upper bound of the norm of the derivative of the sliding surface is available, a weaker and easy to implement assumption in comparison to those of 2‐smc and dsmc. The closed‐loop system accounts explicitly for the invariance condition without reaching phase, and therefore for a desired transient response with global exponential convergence of tracking errors. Preliminary experiments are presented. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of habitat enhancement on 0‐group fishes in a lowland river
Authors: Langler Glenn J. , Smith Carl
Published: August 2002

Loss of habitat complexity through river channelization can have adverse affects on riverine fauna and flora through reductions in abundance and diversity of species. Habitat enhancement schemes are used to improve the physical and biological heterogeneity of riverine habitats. Between 1996 and 1997 the Environment Agency undertook a habitat enhancement scheme on the Huntspill River, Somerset, England to improve conditions for coarse (non‐salmonid) fishes. The scheme involved reducing bank gradients and the construction of off‐channel bays in parts of the channel, all of which were planted with willow (Salix sp.) and common reed (Phragmites australis). The effectiveness of the enhancement scheme was investigated by comparing 0‐group fish assemblages in manipulated and unmanipulated sites. Abundance and diversity of 0‐group fishes was significantly higher in manipulated habitats. There was no significant difference detected in the effects of the different types of enhancement measure used. The significance of microhabitats produced by habitat enhancement schemes is discussed with respect to spawning, nursery and refuge sites for 0‐group coarse fish assemblages. Copyright © 2001 John Wiley & Sons, Ltd.
Kernel‐Based Nonlinear Subspace Method for Pattern Recognition
Authors: Maeda Eisaku , Murase Hiroshi
Published: August 2002

A new pattern classification method called the Kernel‐based Nonlinear Subspace (KNS) method is proposed. It implements a subspace method in a high‐dimensional nonlinear space by a nonlinear transformation defined by kernel functions. The Support Vector Machine, a recent popular current research topic, is a nonlinear classification method employing kernel functions and has advanced classification performance. However, as the number of patterns and the number of classes increase, the problem faced is an explosive increase in the computational complexity needed for learning. Conventional subspace methods are effective classifiers of multiple classes and are fast classification techniques. But satisfactory classification performance is not achieved if the pattern distribution is nonlinear or if the dimensionality of the feature space is small compared to the number of classes. The proposed method combines the advantages of both techniques to compensate for each other's deficiencies to realize nonlinear classification of multiple classes with advanced classification performance and low computational complexity. In this paper, we demonstrate the ability to use nonlinear transforms defined by kernel functions to formulate the nonlinear subspace method, evaluate the proposed method from the perspectives of classification performance for nonlinear distributions and multiclass distributions, the stability of the classification performance with respect to parameter variations, and the computational costs needed for learning and classification, and verify the superiority of the proposed method over conventional methods. © 2001 Scripta Technica, Syst Comp Jpn, 33(1): 38–52, 2002
Convenient calibration of FTIR peak ‘size’ for thin organic/polymer films
Authors: Hooper Andrew E. , Tompkins Harland G.
Published: August 2002

Thin films of organic/polymer material can be fabricated as self‐assembled monolayers and by dip‐coating, spin‐coating, etc. for use in microelectronics, particularly in applications in the BioChip area, molecular electronics, microfluidics and cell‐phone fuel cells. In any analysis the inevitable question is ‘How much’ (not how tall, but how many atoms per square centimeter). A unique feature of organic/polymer films is the molecular vibrations of the organic groups; these can be measured with Fourier transform infrared spectroscopy (FTIR) and we will use this method for quantitation. Using weight gain measurements, we provide the methodology for determining the amount of material in a thin film using transmission FTIR. We provide the calibration factors for CH2, C=O, and N–H bonds using Nylon‐6 as an example. Films as thin as 200 Å are used in this study and we estimate that, under certain conditions, films as thin as a few tens of angstroms could be measured. The calibration factors that we provide can be used directly for films where these functional groups are in similar chemical environments. Where the chemical environments are significantly different, we have suggested a method for determining the appropriate calibration factors. Copyright © 2001 John Wiley & Sons, Ltd.
Imaging the surface potential of active purple membrane
Authors: Knapp Helmut F. , Mesquida Patrick , Stemmer Andreas
Published: August 2002

Bacteriorhodopsin, the light‐driven proton pumping protein in the purple membrane of Halobacterium salinarium, is known to be fully functional in various environments. Because of this, the protein's potential for technological application has been recognized. To investigate bacteriorhodopsin's light‐induced surface potential changes in humid air, we modified our commercial atomic force microscope to allow imaging at controlled humidities and toggling between defined lighting conditions. The purple membrane patches are prepared from solution onto freshly cleaved highly oriented pyrolytic graphite and imaged in the surface potential detection mode, also called Kelvin probe force microscopy, to identify their topography and surface potential in parallel. Precise tuning of the detection mechanism is crucial to allow imaging of the relatively small potential differences on the purple membrane (in the millivolt range). Our results show that the two orientations of the purple membrane can be identified by their surface potential. This is verified by high‐resolution topography images of the patches. Further experiments also show that, for the first time, it was possible to toggle the surface potential of the purple membrane patches by 3–5 mV when imaging the sample in dark or illuminated surrounding in humid air. Copyright © 2002 John Wiley & Sons, Ltd.
Accuracy of point predictions in survival analysis
Authors: Henderson Robin , Jones Margaret , Stare Janez
Published: August 2002

Survival time prediction is important in many applications, particularly for patients diagnosed with terminal diseases. A measure of prediction error taken from the medical literature is advocated as a practicable method of quantifying reliability of point predictions. Optimum predictions are derived for familiar survival models and the accuracy of these predictions is investigated. We argue that poor predictive capability is inherent to standard survival models with realistic parameter values. A lung cancer example is used to illustrate difficulties in prediction in practice. Copyright © 2001 John Wiley & Sons, Ltd.