bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology and mechanical properties of blown films of a low‐density polyethylene/linear low‐density polyethylene blend
Authors: Lu Jianjun , Sue Hung‐Jue
Published: August 2002

The morphologies of films blown from a low‐density polyethylene (LDPE), a linear low‐density polyethylene (LLDPE), and their blend have been characterized and compared using transmission electron microscopy, small‐angle X‐ray scattering, infrared dichroism, and thermal shrinkage techniques. The blending has a significant effect on film morphology. Under similar processing conditions, the LLDPE film has a relatively random crystal orientation. The film made from the LDPE/LLDPE blend possesses the highest degree of crystal orientation. However, the LDPE film has the greatest amorphous phase orientation. A mechanism is proposed to account for this unusual phenomenon. Cocrystallization between LDPE and LLDPE occurs in the blowing process of the LDPE and LLDPE blend. The structure–property relationship is also discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 507–518, 2002; DOI 10.1002/polb.10115
Dislocation approach to the plastic deformation of semicrystalline polymers: Kinetic aspects for polyethylene and polypropylene*
Authors: Séguéla R.
Published: August 2002

The plasticity of semicrystalline polymers is analyzed in the framework of Young's dislocation model under the assumption of nucleation of screw dislocations from the lateral surface of the crystalline lamellae. It is proposed that the driving force for the nucleation and propagation across the crystal width of these screw dislocations relies on chain twist defects that migrate along the chains stems and allow a step‐by‐step translation of the stems through the crystal thickness. Such defects are identified as thermally activated conformational defects responsible for the so‐called crystalline relaxation. Dislocation kinetic equations are derived. Plastic flow rates attainable by dislocation motion in polyethylene and polypropylene are assessed with frequency–temperature data of the crystalline relaxation. Comparisons are made with experimental strain rates that enable homogeneous plastic deformation. In addition to temperature, the crystal lamellar thickness, which is a basic factor of the plastic flow stress in Young's dislocation model, is a major factor in dislocation kinetics through its influence on chain twist activation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 593–601, 2002; DOI 10.1002/polb.10118
Transport and mechanical properties of blends of poly(ϵ‐caprolactone) and a modified montmorillonite‐ poly(ϵ‐caprolactone) nanocomposite
Authors: Gorrasi Giuliana , Tortora Mariarosaria , Vittoria Vittoria , Galli Giancarlo , Chiellini Emo
Published: August 2002

The structural characterization and transport properties of blends of a commercial high molecular weight poly(ϵ‐caprolactone) with different amounts of a montmorillonite‐poly(ϵ‐caprolactone) nanocomposite containing 30 wt % clay were studied. Two different vapors were used for the sorption and diffusion analysis—water as a hydrophilic permeant and dichloromethane as anorganic permeant—in the range of vapor activity between 0.2 and 0.8. The blends showed improved mechanical properties in terms of flexibility and drawability as compared with the starting nanocomposites. The permeability (P), calculated as the product of the sorption (S) and the zero‐concentration diffusion coefficient (D0), showed a strong dependence on the clay content in the blends. It greatly decreased on increasing the montmorillonite content for both vapors. This behavior was largely dominated by the diffusion parameters. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1118–1124, 2002
Structural and mechanical behavior of polypropylene/ maleated styrene‐(ethylene‐co‐butylene)‐styrene/sisal fiber composites prepared by injection molding
Authors: Xie X. L. , Fung K. L. , Li R. K. Y. , Tjong S. C. , Mai Y.‐W.
Published: August 2002

Hybrid composites consisting of isotactic poly(propylene) (PP), sisal fiber (SF), and maleic anhydride grafted styrene‐(ethylene‐co‐butylene)‐styrene copolymer (MA‐SEBS) were prepared by melt compounding, followed by injection molding. The melt‐compounding torque behavior, thermal properties, morphology, crystal structure, and mechanical behavior of the PP/MA‐SEBS/SF composites were systematically investigated. The torque test, thermogravimetric analysis, differential scanning calorimetric, and scanning electron microscopic results all indicated that MA‐SEBS was an effective compatibilizer for the PP/SF composites, and there was a synergism between MA‐SEBS and PP/SF in the thermal stability of the PP/MA‐SEBS/SF composites. Wide‐angle X‐ray diffraction analysis indicated that the α form and β form of the PP crystals coexisted in the PP/MA‐SEBS/SF composites. With the incorporation of MA‐SEBS, the relative amount of β‐form PP crystals decreased significantly. Mechanical tests showed that the tensile strength and impact toughness of the PP/SF composites were generally improved by the incorporation of MA‐SEBS. The instrumented drop‐weight dart‐impact test was also used to examine the impact‐fracture behavior of these composites. The results revealed that the maximum impact force (Fmax), impact‐fracture energy (ET), total impact duration (tr), crack‐initiation time (tinit), and crack‐propagation time (tprop) of the composites all tended to increase with an increasing MA‐SEBS content. From these results, the incorporation of MA‐SEBS into PP/SF composites can retard both the crack initiation and propagation phases of the impact‐fracture process. These prolonged the crack initiation and propagation time and increased the energy consumption during impact fracture, thereby leading to toughening of PP/MA‐SEBS/SF composites. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1214–1222, 2002
A steady‐state mass balance model of the polycarbonate–CO2 system reveals a self‐regulating cell growth mechanism in the solid‐state microcellular process
Authors: Holl M. R. , Garbini J. L. , Murray W. R. , Kumar V.
Published: August 2002

A simple mechanism regulating polymer mobility is demonstrated to determine initial and final growth states of solid‐state microcellular foams. This mechanism, governed by the extent of plasticization of the polymer by the dissolved gases, is examined with a mass balance model and results from foam growth experiments. Polycarbonate was exposed to CO2, which acted as both a plasticizing gas and a physical blowing agent driving foam growth. The polycarbonate specimens were saturated to the equilibrium gas concentration at 25 °C for CO2 pressures of 1–6 MPa in 1‐MPa increments. Equilibrated specimens were heated in a glycerin bath until thermal equilibrium was reached, and a steady foam structure was attained. Glycerin bath temperatures of 30–150 °C in 10 °C increments were examined. Using knowledge of gas solubility, the equation of state for CO2, the effective glass‐transition temperature as a function of gas concentration, and a model for mass balance within a solid‐state foam, we demonstrate that foam growth terminates when sufficient gas is driven from the polycarbonate matrix into the foam cells. The foam cell walls freeze at the elevated bath temperature because of gas transport from the polycarbonate matrix and the associated rise in the polymer glass‐transition temperature to that of the heated bath. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 868–880, 2001
Dynamic mechanical behavior of oriented semicrystalline polyethylene terephthalate
Authors: Xia Zhiyong , Sue Hung‐Jue , Hsieh Alex J. , Huang Joe W.‐L.
Published: August 2002

The dynamic mechanical behavior of molecularly oriented semicrystalline polyethylene terephthalate (PET) induced via the equal‐channel angular extrusion (ECAE) process was investigated. Dynamic mechanical analyses in both torsional mode and bending mode were utilized. The results indicate that the ECAE‐oriented PET has a higher dynamic storage modulus above the glass‐transition temperature than that of the reference (control sample). The combined effect of molecular orientation and crystallinity is responsible for the changes in the primary and secondary relaxations of PET. Further analyses show that the shifting and broadening of the primary and secondary peak positions in oriented PET are mainly due to the amorphous‐phase orientation because the crystallinity of PET decreases upon the ECAE processing. A good correlation was found between the structural anisotropy and the dynamic mechanical properties. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1394–1403, 2001
Onsager consistency checks for multicomponent diffusion models
Authors: Zielinski John M. , Alsoy Sacide
Published: August 2002

The Onsager reciprocity relations are applied to several recently proposed multicomponent diffusion models in an attempt to gauge their validity and ascertain their applicability. Each of these friction‐based diffusion models stems from the more general Bearman formalism through various assumptions regarding the individual friction coefficients. By assessing the compliance of the Bearman model with respect to the Onsager relations, we ascertain the validity of the simplifications introduced to each diffusion model and suggest which postulates lead to results consistent with the Onsager relations. Although some models are not consistent with the Onsager relations, each model predicts the multicomponent drying of polymer films reasonably well. The necessity for consistency with the Onsager development is, therefore, revisited. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1496–1504, 2001
Phase behavior and viscoelastic properties of entangled block copolymer gels
Authors: Vega Daniel A. , Sebastian John M. , Loo Yueh‐Lin , Register Richard A.
Published: August 2002

Triblock copolymers in midblock‐selective solvents can form physical gels. However, at low triblock contents (near the percolation threshold), the bridging of chains between micelles can lead to macrophase separation. Adding a styrene–isoprene diblock to a styrene–isoprene–styrene triblock copolymer in squalane can eliminate macrophase separation, yielding a wide range of stable, single‐phase gels with a disordered arrangement of micelles. The plateau modulus of these triblock gels scales with the 2.2 power of polymer content, indicating the importance of entanglements in dictating the modulus. Comparing gels made from the midblock‐saturated derivative of the same polymer [styrene‐(ethylene‐alt‐propylene)‐styrene] in squalane reveals that the modulus differences in the gels are a direct consequence of the difference in the entanglement molecular weight of the midblock homopolymer in bulk. Finally, the broad relaxation spectrum of these triblocks is well‐described by a recent theory for the dynamics of entangled star polymers, with the breadth of the relaxation spectrum dictated by the number of entanglements per midblock in the gel. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2183–2197, 2001
Effects of composition drift on the effectiveness of random copolymer reinforcement at polymer–polymer interfaces
Authors: Benkoski J. J. , Fredrickson G. H. , Kramer E. J.
Published: August 2002

Random copolymer layers are surprisingly effective at reinforcing polymer–polymer interfaces. One hypothesis is that composition drift during synthesis can account for the higher than expected toughening. To test this hypothesis, we polymerized a series of poly(d‐styrene‐r‐2‐vinylpyridine) (dPSf‐r‐PVP1−f) copolymers with various fractions (f) of deuterated styrene to only 10% completion to avoid composition drift. The fracture energies (Gc) of polystyrene/dPS‐r‐PVP/poly(2‐vinylpyridine) interfaces with relatively thick layers of dPS‐r‐PVP were measured. Gc decreased relative to interfaces reinforced with composition‐drifted dPS‐r‐PVP. Conversely, Gc increased when two or more copolymers were blended together. In such samples, the copolymers form distinct layers with multiple interfaces characterized by the difference in f (Δf) between adjacent layers. We find that Gc is governed by Δfmax, the largest difference in adjacent compositions, and, therefore, by the width of the narrowest interface (wmin). Gc increases strongly as wmin increases from 3 to 5 nm. Remarkably, these wmin values are about half the entanglement spacing in bulk polystyrene. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2363–2377, 2001
Psychometric properties of the Impact of Event Scale amongst women at increased risk for hereditary breast cancer
Authors: Thewes Belinda , Meiser Bettina , Hickie Ian B.
Published: August 2002

The Impact of Event Scale (IES; Horowitz MJ, Wilner N, Alvarez W. 1979. Psychosom Med 41: 209–218) has been widely used in the psycho‐oncology literature as a measure of cancer‐related anxiety. More recently, the IES has been applied to the assessment of breast cancer‐related anxiety amongst women who are at increased risk of developing hereditary breast cancer. Despite its widespread use, no studies to date have described the validity of the IES amongst these women. The present study is a replication of reliability analyses and exploration of the factor structure and validity of the IES amongst a sample of 480 female hereditary breast cancer clinic patients. Results suggest good internal consistency (Cronbach's α=0.84–0.91), and satisfactory test‐retest reliability (IES‐Total r=0.80). The IES was found to have good face validity and be an acceptable instrument to women at increased risk of breast cancer. The two‐factor (intrusion and avoidance) structure originally reported (Horowitz et al. 1979; Zilberg NJ, Weiss DS, Horowitz MJ. 1982. J Consult Clin Psychol 50: 407–414) was replicated by factor analysis in the present study. Analysis of correlation coefficients between the IES, breast cancer‐related events and attitudes and other standardized measures of distress and general somatic concern, provide some preliminary support for the concurrent and discriminative validity of the IES amongst women at increased risk of developing hereditary breast cancer. Copyright © 2001 John Wiley & Sons, Ltd.
The radar signatures and age of periglacial slope deposits, Central Highlands of Germany
Authors: Völkel J. , Leopold M. , Roberts M. C.
Published: August 2002

Determining the age of periglacial slope deposits (head) in the Central Highlands (Mittelgebirge) of Germany is a research challenge because of the lack of dateable organics and the contentious role of the Laacher See Tephra (LST) as a dating indicator. Ground penetrating radar (GPR) and cores were used to establish the subsurface stratigraphic relationships between the peat deposits of two bogs (Totenauer Moor, Bayerischer Wald and Schwarzes Moor, Rhön) and underlying head deposits in order to provide minimum ages for the head. Radiocarbon dates were obtained from peat bogs overlying the head in the Bavarian Forest, while in the Rhön (Schwarzes Moor) LST was found bedded in the peat above the head indicating that the latter therefore, is older than Alleröd. Radar profiles show that the head is a stratigraphically continuous, not interbedded, unit beneath the peat. The lowest peat at Totenauer Moor, immediately above the Upper Head, was dated at 11,550 ± 260 yr BP thus establishing the minimum age of the Upper Head as being older than Bölling and perhaps even Older Dryas, but not Younger Dryas. The LST shards were not deposited contemporaneously with the head but were incorporated by bioturbation and mass movements. This study demonstrated the utility of GPR as a tool for imaging head deposits. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of tobramycin solution for inhalation on global ratings of quality of life in patients with cystic fibrosis and Pseudomonas aeruginosa infection*†
Authors: Quittner Alexandra L. , Buu Anne
Published: August 2002

In a previously published placebo‐controlled trial, tobramycin solution for inhalation (TSI) was shown to improve lung function and other outcomes in patients with cystic fibrosis (CF). The objectives of the current study were to examine the effects of TSI on global ratings of health‐related quality of life (HRQOL) by patients (or their parents) and physicians blind to group assignment, and to determine whether any perceived benefits persisted over time. The global ratings of HRQOL in 520 patients with CF and chronic Pseudomonas aeruginosa infection were analyzed retrospectively. Patients were randomly assigned to receive 24 weeks of placebo or treatment with TSI 300 mg b.i.d., both administered in cycles of 28 days on drug (or placebo) followed by 28 days off, for a total of three cycles. After each on‐drug cycle, patients or parents, and physicians, were asked to rate whether the patient's condition was better, unchanged, or worse.

There was strong agreement between the paired patient/parent and physician global HRQOL ratings across the three cycles. Regression analyses demonstrated that patients in the TSI group were significantly more likely to report improvements in HRQOL than were patients in the placebo group. This effect was found to be both immediate (end of on‐drug cycle 1) and delayed (end of subsequent on‐drug cycles 2 and 3) (P < 0.05). In addition, change in forced expired volume in 1 sec (FEV1) % predicted values was a significant predictor of improvement in HRQOL ratings by patients and parents. After controlling for change in FEV1 % predicted, physician ratings showed significant improvement only at the end of cycle 1. Finally, controlling for initial lung disease severity, longitudinal growth models revealed that patients on TSI and their physicians reported higher HRQOL ratings than did placebo patients and their physicians across the three cycles; however, the magnitude of this effect decreased over time.

Results of this study provided consistent evidence that TSI was associated with improved global ratings of HRQOL completed by both patients or parents, and physicians. Although these results are promising, they are limited by the use of a single‐item rating of health. Future studies of the effects of TSI should utilize a well‐validated, disease‐specific measure of HRQOL. Pediatr Pulmonol. 2002; 33:269–276. © 2002 Wiley‐Liss, Inc.
Familial dysautonomia: A diagnostic dilemma. Chronic lung disease with signs of an autoimmune disease
Authors: van Egmond‐Fröhlich A.W.A. , Paul K. , Eggert W. , Gaedicke G. , Wahn U. , Bauer C.‐P.
Published: August 2002

We present an 11‐year‐old girl with sensory and autonomic neurological dysfunction, and respiratory insufficiency caused by recurrent aspiration. The diagnosis of familial dysautonomia (FD) was confirmed by a missing axonal flare to histamine, miosis in response to conjunctival methacholine and homozygous polymorphic linked markers DS58(18) and DS159(7) on chromosome 9. Ashkenazi Jewish descent could not be ascertained by history. A variety of positive tests for autoantibodies were initially interpreted as evidence for systemic lupus erythematosus vs. overlap syndrome with pulmonary, cerebral, skin, and ocular involvement. The diagnosis of FD was delayed because of the rarity of this disorder in Germany (second case reported). We discuss possible explanations for the misleading immunological findings, including interference by antibodies binding to milk proteins used as blocking reagents in enzyme‐linked immunoassays and circulating immune‐complexes due to chronic aspiration pneumonitis. Pediatr Pulmonol. 2001; 31:478–481. © 2001 Wiley‐Liss, Inc.
Mechanisms of cholinergic dysfunction in rabbits following recurrent aspiration of cow's milk*
Authors: Larsen Gary L. , Loader Joan , Nguyen Dee Dee , Colasurdo Giuseppe N.
Published: August 2002

Recurrent aspiration of cow's milk has been shown to alter neural control of airways in young rabbits (Gelfand et al., 1997). The purpose of this study was to define the mechanisms responsible for in vitro cholinergic hyperresponsiveness in this model. Beginning at 1 week of age, rabbits received either 0.5 mL/kg whole cow's milk or sterile saline intranasally while under light anesthesia. This was repeated each weekday for 2 weeks. At 8 weeks of age, rabbits were sacrificed. Portions of lungs underwent lavage with sterile saline. Tracheal smooth muscle (TSM) segments were also removed. Segments were assessed for acetylcholine (ACh) release by high‐performance liquid chromatography ( HPLC) with electrochemical detection or acetylcholinesterase (AChE) kinetic activity by spectrophotometry. Substance P (SP), a neuropeptide that can increase ACh release from nerves, was also assessed using an enzyme immunoassay to define the content in lavage and TSM segments. Immunohistochemistry for SP within airways was also assessed.

We found that recurrent aspiration of milk led to statistically significant alterations in many parameters. Acetylcholine release was significantly greater in segments of airways from rabbits that had aspirated cow's milk (27.5 ± 1.7 vs. 20.1 ± 1.6 pmol/min/g tissue) than saline. At the same time, AChE activity was less in the group that aspirated milk (8.7 ± 0.4 vs. 10.2 ± 0.5 nmol/min/mg protein) compared to saline. The amount of SP within both lavage as well as tissue homogenates was greater in the group that had aspirated the foreign protein (159.1 ± 28.9 vs. 41.9 ± 5.2 pmol/mg protein in lavage; 158.7 ± 31.9 vs. 80.5 ± 7.8 pmol/mg protein in tissues) than saline controls. While total cholinergic nerve density as assessed by choline acetyltransferase was not significantly different between groups, SP‐positive immunoreactive nerves were easily identified in the group that aspirated cow's milk.

This study suggests that cholinergic hyperresponsiveness caused by repeated aspiration of milk is due to several abnormalities, including prejunctional (increase in ACh release) as well as junctional (decrease in AChE) mechanisms within the airways. In addition, an upregulation of SP within airways is part of this process. Pediatr Pulmonol. 2001; 32:409–417. © 2001 Wiley‐Liss, Inc.
Oxygen saturation in adult cystic fibrosis patients during exercise at high altitude
Authors: Ryujin Darin T. , Mannebach Steven C. , Samuelson Wayne M. , Marshall Bruce C.
Published: August 2002

The objective of this study was to determine the frequency and severity of decreased arterial oxy‐hemoglobin saturation during exercise in adults with cystic fibrosis at 1,500 m above sea level. A convenience sample of 50 adults with cystic fibrosis who did not have hypoxemia (oxygen saturation, < 90%) at rest were evaluated. Spirometry was performed according to American Thoracic Society standards, and maximal exercise tests were performed on an electronically braked cycle ergometer using a ramp protocol individualized for each patient. Pulse oximetry was measured every 2 min.

When exercising at high altitude, 45 of 50 patients had a decrease in arterial oxy‐hemoglobin saturation from baseline to some degree. In 29 patients, oxy‐hemoglobin saturation fell below 90%; in 14 patients, it fell below 85%; and in 4 patients, it fell below 80%. Oxy‐hemoglobin saturation decreased to < 90% in 12 of 14 patients with severe pulmonary disease (FEV1 < 40% predicted), in 15 of 26 patients with moderate disease (40% less than or equal to FEV1 < 70% predicted), in 2 of 6 patients with mild disease (70% less than or equal to FEV1 < 90% predicted), and in 0 of 4 with normal pulmonary function (FEV1 greater than or equal to 90%). Percent predicted FEV1 (r = 0.57; P < 0.0001) and FEV1/FVC ratio (r = 0.52; P < 0.0001) most highly correlated with arterial oxy‐hemoglobin saturation at peak exercise.

We conclude that at 1,500 m above sea level, adult CF patients with obstructive airways disease are at significant risk for decreased arterial oxy‐hemoglobin saturation during exercise. A supervised exercise test should be considered prior to recommending an exercise program for such patients. Pediatr Pulmonol. 2001; 32:437–441. © 2001 Wiley‐Liss, Inc.
Quantitative analysis of end‐tidal carbon dioxide during mechanical and spontaneous ventilation in infants and young children
Authors: Hsieh Kai‐Sheng , Lee Cheng‐Liang , Lin Chu‐Chuan , Wu Sheng‐Nan , Ko Fang‐Yuan , Huang Yung‐Feng , Huang Ta‐Cheng
Published: August 2002

Capnography provides a substitute for monitoring of arterial carbon dioxide tension (PCO2). We performed a prospective study to evaluate a new application of capnography, using quantitative curve analysis in the pediatric ICU. Twenty‐five infants and children admitted to the pediatric ICU after cardiovascular surgery for congenital heart diseases were included in the study. Capnographic curves were recorded during 3 phases of mechanical and spontaneous ventilation: phase 1, immediate postoperative period; phase 3, preextubation period; and phase 2, period between phases 1 and 3. Each recording included 17 sec of capnographic tracings from consecutive spontaneous and/or ventilator‐driven breaths. Quantitative curve analysis was made to define parameters including peak value of exhaled PCO2 (P), mean rate of rise of PCO2 (R), and area under each capnographic curve (A).

Qualitative inspection of the wave contour showed no obvious difference in phase 3 during spontaneous and mechanically assisted ventilator breaths. However, an obvious difference existed between spontaneous and mechanically assisted breaths in phase 2. For each parameter (P, R, and A), there was a significant difference in phases 2 and 3 from spontaneous breaths. However, there was no significant difference in phases 2 and 3 from ventilator‐assisted breaths. We further calculated the ratio of parameters of spontaneous breaths (S) and ventilator‐assisted breaths (V) in phase 2 and phase 3. The ratio of S/V for P, R, and A showed significant differences between phase 2 and phase 3.

We conclude that quantitative analysis of exhaled end‐tidal PCO2 curves revealed significant changes of specific parameters during the transition from the ventilator‐dependent state to the spontaneously breathing ventilator‐independent state. This new approach provides a new way to estimate respiratory status in infants and children receiving ventilator therapy. Through quantitative capnographic curve analysis, if P, R, and A from spontaneous breaths approached those of ventilator‐assisted breaths, patients have resumed reasonable pulmonary mechanics, and extubation may then be considered. Pediatr Pulmonol. 2001; 32:453–458. © 2001 Wiley‐Liss, Inc.
Congenital cystic adenomatoid malformation type 4
Authors: van Koningsbruggen Silke , Ahrens F. , Brockmann M. , Michalk D. , Rietschel E.
Published: August 2002

A 9‐day‐old boy presented in respiratory distress and with failure to thrive. The chest X‐ray showed a hyperlucent area of the left lung. A resection of the markedly emphysematous segment 2 of the left upper lobe was performed assuming the emphysematous tissue was due to congenital lobar emphysema (CLE). Histological examination of the lung tissue, however, revealed a pattern consistent with congenital cystic adenomatoid malformation (CCAM) type 4.

The therapy for CLE as well as for CCAM is similar, i.e., resection of the emphysematous tissue. As far as the prognosis is concerned, it is important to diagnose the exact type of malformation in order to exclude associated anomalies, as well as the risk of development of malignancies in later life.

The frequency of associated malformations of CCAM type 4 is unknown. Although the risk for development of malignancies from CCAM type 4 is not clear at the moment, the possible development of malignancies justifies prompt resection shortly after diagnosis, even in asymptomatic patients. A life‐long follow‐up in those patients who had a resection of CCAM in early childhood is recommended. Pediatr Pulmonol. 2001; 32:471–475. © 2001 Wiley‐Liss, Inc.
Down‐regulation of the human kallikrein gene 5 (KLK5) in prostate cancer tissues
Authors: Yousef George M. , Scorilas Andreas , Chang Albert , Rendl Laura , Diamandis Maria , Jung Klaus , Diamandis Eleftherios P.
Published: August 2002

BACKGROUND

Kallikreins are a subgroup of serine proteases with diverse physiological functions. Many kallikrein genes are differentially expressed in various malignancies and prostate specific antigen (PSA; encoded by the KLK3 gene) is the best tumor marker for prostate cancer. Human glandular kallikrein (hK2; encoded by the KLK2 gene) is an emerging tumor marker for prostate cancer. KLK5 is a newly discovered human kallikrein gene which shares a high degree of homology and is located adjacent to KLK2 and KLK3 genes on chromosome 19q13.4. Like KLK2 and KLK3, the KLK5 gene is regulated by steroid hormones in the BT‐474 breast cancer cell line. We have previously shown that KLK5 is differentially expressed in ovarian and breast cancer.

METHODS

We compared the expression of KLK5 in 29 pairs of histologically confirmed normal and prostate cancer tissues by quantitative RT‐PCR using the LightCycler technology.

RESULTS

KLK5 expression was significantly lower in cancer tissues compared to their normal counterparts. Lowest levels of expression were found in T3 stage tumors compared with T1 and T2. Also, a significant negative correlation was found between Gleason score and KLK5 expression.

CONCLUSIONS

KLK5 should be further studied as a potential new prognostic marker in prostate cancer, whose expression is negatively correlated with cancer aggressiveness. Prostate 51: 126–132, 2002. © 2002 Wiley‐Liss, Inc.
Alternative splicing isoforms of hippostasin (PRSS20/KLK11) in prostate cancer cell lines
Authors: Nakamura Terukazu , Mitsui Shinichi , Okui Akira , Kominami Katsuya , Nomoto Takeshi , Ukimura Osamu , Kawauchi Akihiro , Miki Tsuneharu , Yamaguchi Nozomi
Published: August 2002

BACKGROUND

Hippostasin is a kallikrein‐like protease (PRSS20/KLK11), which is expressed preferentially in the hippocampus and prostate. We have reported that alternative splicing variants of human hippostasin are regulated in a tissue‐specific manner. Brain‐type hippostasin consists of 250 amino acids including a typical signal sequence, and is expressed in the brain and prostate. The prostate‐type hippostasin, which has 32 extra amino acids at the N‐terminal end, is expressed only in the prostate.

METHODS

We analyzed the expression and localization of hippostasin in normal prostate tissue, BPH tissue, and prostate cancer cell lines. We performed northern blotting, in situ hybridization, immunohistochemistry, and RT‐PCR.

RESULTS

Hippostasin mRNA is expressed preferentially in the normal prostate and weakly in the testis. It was detected in prostate secretory epithelium. Hippostasin protein was localized in the prostate secretory epithelium, and western blotting showed that hippostasin was present in semen. All tested prostate cancer cell lines, including PSA‐negative cell lines, expressed hippostasin. Interestingly, all the prostate cancer cell lines expressed only brain‐type but not prostate‐type hippostasin, while normal prostate and BPH expressed both types of hippostasin

CONCLUSIONS

Our results suggest the possibility that hippostasin may be a useful marker by which prostate cancer and BPH can be distinguished Prostate 49:72–78, 2001. © 2001 Wiley‐Liss, Inc.
Repeated biopsies in evaluation of therapeutic effects in prostate carcinoma
Authors: Szende B. , Romics I. , Minik K. , Szabó J. , Torda I. , Lovász S. , Szomor L. , Tóth L. , Bély M. , Kerényi T. , Bartók K. , Végh A.
Published: August 2002

Background

Apoptosis is one of the major events following total androgen blockade (TAB). The aim of this study was to determine the predictive value of some histological parameters including apoptosis and gene products which influence apoptosis, based on repeated biopsies taken from the same patients.

Methods

At the time of diagnosis by needle biopsy TNM stage, serum PSA, Gleason's grade, apoptotic and mitotic index, Ki67, p53, and bcl2 expression were investigated in 60 prostate carcinoma patients. Antiandrogen therapy supplemented with surgical or chemical castration was administered. Serum PSA‐test and needle biopsy were repeated 13–14 weeks after starting the therapy, simultaneously with determination of the apoptotic and mitotic index, Ki67, p53, and bcl2 expression.

Results

Forty‐seven patients were alive at the end of the study, 13 patients died. Decrease in mitotic, increase in apoptotic index predicted favourable long‐term response to antiandrogen therapy. Lower Ki67 and (mutant) p53 expression in the first and also in the second biopsy pointed to favourable effect of antiandrogen treatment. Since the ratio between Ki67 and apoptotic index strongly decreased in the survivors upon therapy, changes in Ki67/apoptosis ratio is recommended as a histologically detectable predictive factor. bcl2 expression did not show significant correlation with the outcome of the disease.

Conclusions

Histological evaluation of mitotic and apoptotic index, Ki67, and p53 expression in repeated biopsies contributes to predicting the value of the actual treatment and may be useful to institute alterations in therapy. Prostate 49:93–100, 2001. © 2001 Wiley‐Liss, Inc.
Relationship of p21WAF‐I protein expression with prognosis in advanced prostate cancer treated by androgen ablation
Authors: Omar Eltaher A. , Behlouli Hassan , Chevalier Simone , Aprikian Armen G.
Published: August 2002

Objectives

The objectives of our study were (1) to characterize the expression of p21 and p53 proteins in advanced stage prostate cancer, (2) to determine the relationship between p53 and p21 protein expressions, and (3) to relate p53 and p21 expression to clinical outcome after androgen ablation.

Methods

Seventy‐five patients with advanced prostate cancer (clinical stage C: 11, stage D1: 8, stage D2: 56), who all underwent androgen ablation, had tissue specimens obtained prior to hormonal therapy and studied immunohistochemicaly for p53 (Mab D07) and p21 (Mab EA10) expression. Clinical outcome was analyzed using the Kaplan–Meier method and log‐rank tests. Cox proportional hazard model was used to determine the independence of multiple variables.

Results

About 33.3% of cases expressed p53 and 33.3% expressed p21 positive immunoreactivity. No statistically significant correlation between p21 and p53 expression either in the entire study group (N = 75) or in stage D2 cases (N = 56) was observed (P = 0.38 and P = 0.68, respectively). Disease‐specific survival was significantly related to p21 expression (P = 0.0006 for entire study group and P = 0.01 for D2 cases). There was no statistically significant differences in disease‐specific survival between p53 positive or negative cases (P = 0.38 overall, P = 0.7 stage D2 only). p21 expression and the number of bone lesions were independently associated with shorter survival (multivariate P = 0.001, P = 0.005, respectively).

Conclusions

The data suggests that p21 expression is a strong and independent poor prognostic factor in patients with advanced stage prostate cancer treated by androgen ablation. Prostate 49:191–199, 2001. © 2001 Wiley‐Liss, Inc.
Anti‐cooperativity and cooperativity in hydrophobic interactions: Three‐body free energy landscapes and comparison with implicit‐solvent potential functions for proteins
Authors: Shimizu Seishi , Chan Hue Sun
Published: August 2002

Potentials of mean force (PMFs) of three‐body hydrophobic association are investigated to gain insight into similar processes in protein folding. Free energy landscapes obtained from explicit simulations of three methanes in water are compared with that predicted by popular implicit‐solvent effective potentials for the study of proteins. Explicit‐water simulations show that for an extended range of three‐methane configurations, hydrophobic association at 25°C under atmospheric pressure is mostly anti‐cooperative, that is, less favorable than if the interaction free energies were pairwise additive. Effects of free energy nonadditivity on the kinetic path of association and the temperature dependence of additivity are explored by using a three‐methane system and simplified chain models. The prevalence of anti‐cooperativity under ambient conditions suggests that driving forces other than hydrophobicity also play critical roles in protein thermodynamic cooperativity. We evaluate the effectiveness of several implicit‐solvent potentials in mimicking explicit water simulated three‐body PMFs. The favorability of the contact free energy minimum is found to be drastically overestimated by solvent accessible surface area (SASA). Both the SASA and a volume‐based Gaussian solvent exclusion model fail to predict the desolvation barrier. However, this barrier is qualitatively captured by the molecular surface area model and a recent “hydrophobic force field.” None of the implicit‐solvent models tested are accurate for the entire range of three‐methane configurations and several other thermodynamic signatures considered. Proteins 2002;48:15–30. © 2002 Wiley‐Liss, Inc.
Some insights into protein structural class prediction
Authors: Zhou G.P. , Assa‐Munt Nuria
Published: August 2002

It has been quite clear that the success rate for predicting protein structural class can be improved significantly by using the algorithms that incorporate the coupling effect among different amino acid components of a protein. However, there is still a lot of confusion in understanding the relationship of these advanced algorithms, such as the least Mahalanobis distance algorithm, the component‐coupled algorithm, and the Bayes decision rule. In this communication, a simple, rigorous derivation is provided to prove that the Bayes decision rule introduced recently for protein structural class prediction is completely the same as the earlier component‐coupled algorithm. Meanwhile, it is also very clear from the derivative equations that the least Mahalanobis distance algorithm is an approximation of the component‐coupled algorithm, also named as the covariant‐discriminant algorithm introduced by Chou and Elrod in protein subcellular location prediction (Protein Engineering, 1999; 12:107–118). Clarification of the confusion will help use these powerful algorithms effectively and correctly interpret the results obtained by them, so as to conduce to the further development not only in the structural prediction area, but in some other relevant areas in protein science as well. Proteins 2001;44:57–59. © 2001 Wiley‐Liss, Inc.
Protochlorophyllide oxidoreductase: A homology model examined by site‐directed mutagenesis
Authors: Townley Helen E. , Sessions Richard B. , Clarke Anthony R. , Dafforn Timothy R. , Griffiths W. Trevor
Published: August 2002

An homology model of protochlorophyllide reductase (POR) from Synechocystis sp. was constructed on a template from the tyrosine‐dependent oxidoreductase family. The model showed characteristics appropriate to a globular, soluble protein and was used to generate a structure of the ternary complex of POR, nicotinamide adenine dinucleotide phosphate (NADPH), and protochlorophyllide. The POR ternary model was validated by mutagenesis experiments involving predicted coenzyme‐binding residues and by chemical modification experiments. A core tryptophan residue was shown to be responsible for much of the protein's fluorescence. Both quenching of this residue by coenzyme and fluorescence resonance energy transfer (FRET) from the protein to the coenzyme allowed the binding constant of NADPH to be determined. Replacement of this residue by Tyr gave an active mutant with approximately halved fluorescence and a negligible FRET signal, consistent with the role of this residue in energy transfer to the NADPH at the active site and with the model. The mechanism of the enzyme is discussed in the context of the model and semiempirical molecular orbital calculations. Proteins 2001;44:329–335. © 2001 Wiley‐Liss, Inc.
Computation and mutagenesis suggest a right‐handed structure for the synaptobrevin transmembrane dimer
Authors: Fleming Karen G. , Engelman Donald M.
Published: August 2002

Biological membrane fusion involves a highly precise and ordered set of protein–protein interactions. Synaptobrevin is a key player in this process. Mutagenesis studies of its single transmembrane segment suggest that it dimerizes in a sequence specific manner. Using the computational methods developed for the successful structure prediction of the glycophorin A transmembrane dimer, we have calculated a structural model for the synaptobrevin dimer. Our computational search yields a well‐populated cluster of right‐handed structures consistent with the experimentally determined dimerization motif. The three‐dimensional structure contains an interface formed primarily by leucine and isoleucine side‐chain atoms and has no interhelical hydrogen bonds. The model is the first three‐dimensional picture of the synaptobrevin transmembrane dimer and provides a basis for further focused experimentation on its structure and association thermodynamics. Proteins 2001;45:313–317. © 2001 Wiley‐Liss, Inc.
Non‐competitive GABA antagonists: probing the mechanisms of their selectivity for insect versus mammalian receptors
Authors: Ozoe Yoshihisa , Akamatsu Miki
Published: August 2002

A great variety of non‐competitive antagonists of ionotropic γ‐aminobutyric acid (GABA) receptors have been reported. While they are structurally diverse, there are common features in their structures. Thus, it was hypothesized that they bind to an identical site in different or overlapping orientations, and this hypothesis was validated by three‐dimensional structure–activity relationship (3D‐QSAR) analysis using receptor‐binding data. Meanwhile, although most antagonists are highly toxic to both vertebrates and invertebrates, several classes of antagonists, such as nor‐diterpene lactone picrodendrins, phenyl heterocyclic compounds and disubstituted bicyclophosphorothionates, were found to exhibit selectivity for housefly versus rat GABA receptors. To probe their selectivity mechanisms, the 3D‐QSAR method was applied to the three classes of antagonists. This revealed several important differences that might be related to the selectivity of antagonists between the structures of the non‐competitive antagonist‐binding sites of housefly and rat GABA receptors.

© 2001 Society of Chemical Industry
Synthesis and anthelmintic activity of thioamide analogues of cyclic octadepsipeptides such as PF1022A
Authors: Jeschke Peter , Harder Achim , Etzel Winfried , Gau Wolfgang , Thielking Gerhard , Bonse Gerhard , Iinuma Katsuharu
Published: August 2002

The tetra‐ and mono‐thionated cyclic octadepsipeptides represent novel cyclic octadepsipeptide derivatives with broad‐spectrum activity against parasitic nematodes in mice and sheep. Some of these show better activity than the potent natural anthelmintic cyclic octadepsipeptide PF1022A against Hymenolepis nana, Heterakis spumosa and Trichinella spiralis larvae in mice. In particular, they show improved efficacy against Haemonchus contortus and Trichostrongylus colubriformis in sheep compared with PF1022A. Here we report on two different and simple synthetic pathways for this new class of thionated cyclic octadepsipeptides.

© 2001 Society of Chemical Industry
Biological activity of astilbin from Dimorphandra mollis against Anticarsia gemmatalis and Spodoptera frugiperda
Authors: Batista Pereira Luciane G , Petacci Fernando , Fernandes João B , Corrêa Arlene G , Vieira Paulo C , da Silva M Fátima G F , Malaspina Osmar
Published: August 2002

Astilbin was isolated in high yield from Dimorphandra mollis, and its insecticidal and growth inhibiting activity by stomach ingestion were evaluated against Anticarsia gemmatalis and Spodoptera frugiperda. The insecticidal activity of astilbin, the weight reduction of the larval phase and the prolongation of the larval and pupal phases were verified for both species. Astilbin was identified on the base of its NMR, MS and physical data.

© 2002 Society of Chemical Industry
Medicines for sea lice
Authors: Grant Andrew N
Published: August 2002

Sea louse (Family Caligidae: genera Caligus and Lepeophtheirus) infection of farmed salmonids represents a significant threat to animal welfare and undermines profitability. Lice may also act as vectors for the transmission of viral and bacterial pathogens. Pest‐control programmes parallel those deployed in terrestrial livestock farming and include the use of parasiticides. The authorisation process for fish medicines varies widely between salmon farming countries and undue regulatory constraint may place farmers in one country at a competitive disadvantage. In many jurisdictions, fish are a ‘minor’ species and mounting demands for environmental assessment increase registration costs. A successful integrated louse‐management strategy requires free access to a range of effective, chemically unrelated active ingredients deployed according to current best practice. Over‐reliance on a limited number of products will lead, inevitably, to resistance, which is difficult to counter.

© 2002 Society of Chemical Industry
A diepitopic sequential oligopeptide carrier (SOCn) as mimic of the Sm autoantigen: synthesis, conformation and biological assays
Authors: Alexopoulos Charalampos , Tsikaris Vassilios , Rizou Catherina , Panou‐Pomonis Eugenia , Sakarellos‐Daitsiotis Maria , Sakarellos Constantinos , Vlachoyiannopoulos Panayiotis G. , Moutsopoulos Haralampos M.
Published: August 2002

Anti‐Sm (Sm: U1‐U6 RNA‐protein complex) antibodies are usually considered highly specific for systemic lupus erythematosus (SLE), while anti‐U1RNP (U1RNP: U1RNA‐protein complex) are thought of as diagnostic criteria for the mixed connective tissue disease (MCTD). However, both antibody specificities coexist in SLE and MCTD, in varying percentages. Although the anti‐Sm/anti‐U1RNP immunological cross‐reactivity has been initially attributed to a common motif, PPXY(Z)PP (where X, Y, Z are various amino acids), found in the Sm, U1‐A and U1‐C autoantigens, it appears that the conformational features of the Sm epitopes also play an important role in the immunoreactivity. The PPGMRPP and PPGIRGP main epitopes of the Sm antigen were coupled in duplicate to the tetrameric Ac‐(Lys‐Aib‐Gly)4‐OH, SOC4, carrier to form the [(PPGMRPP)2, (PPGIRGP)2]‐SOC4 construct as a mimic of the native Sm. It was found that: (i) the 310 helical structure of SOC4 allows the epitopes to adopt an exposed orientation, similar to their free forms, that facilitates their recognition from the anti‐Sm antibodies, and (ii) the U1‐RNP cross‐reactivity is minimized. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Imidazoline pseudodipeptides as mimics of reverse turn structures
Authors: Jones Raymond C.F. , Dickson James
Published: August 2002

The synthesis of an imidazoline dipeptide mimetic (a 4,5‐dihydroimidazole‐4‐carboxylic acid) is reported that displays an intramolecular hydrogen‐bond consistent with a turn conformation in solution. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Study of different coupling agents in the conjugation of a V3‐based synthetic MAP to carrier proteins
Authors: Cruz Luis J. , Iglesias Enrique , Aguilar Julio C. , Quintana Diogenes , Garay Hilda E. , Duarte Carlos , Reyes Osvaldo
Published: August 2002

The conjugation of synthetic peptides to carrier proteins is a widely used method for immunological studies. Different coupling agents have been described to form the conjugate with carrier proteins. In this paper, we demonstrate that the antibody response toward V3‐based synthetic MAPs derived from HIV‐1, JY1 isolate, conjugated to two different carrier proteins using either m‐maleimidobenzoyl‐N‐hydroxysuccinimide ester (MBS) or β‐maleimidopropionic acid N‐hydroxysuccinimide ester (MPS), or succinic anhydride (SA) show different behaviors. An excellent anti‐JY1 response without a strong response to the coupling agent is observed in the case of succinic anhydride spacer. In contrast, MBS produces total abrogation of the antibody response with a high response toward the coupling agent. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.