bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in the physical and biochemical properties of pearl millet (Pennisetum americanum) on conversion to ogi
Authors: Akingbala John O , Uzo‐Peters Phyllis I , Jaiyeoba Cordelia N , Baccus‐Taylor Gail S H
Published: October 2002

Millet was converted into ogi, a naturally fermented cereal product, by the traditional wet milling/wet sieving process and by fermenting millet meal and ground millet malt. Proximate chemical composition, flavanol content, vitamin A and B2 contents, energy value, protein and starch availabilities and Brabender paste viscosity of millet grain and ogi were determined. Yields of ogi ranged from 67.5 to 96.5%. Protein, ether extract, ash and crude fibre contents were reduced in ogi by 2.3–24, 3.9–25.5, 14.3–28.6 and 6.6–42.3% respectively, while the soluble carbohydrate content of the grain (68.2 ± 12 g kg−1) was retained. Flavanol content of millet (1.025 g c‐glycosylflavanol equivalent kg−1 grain) was reduced in ogi (0.643–0.872 g c‐glycosylflavanol equivalent kg−1 grain). Vitamin A content was reduced by 21.4–53.4% and vitamin B2 content was increased by 85.7–242.8% on conversion of millet into ogi. Apparent protein availability increased by 91.3–144.9% with papain digestion and by 47.6–109.5% without papain. However, changes in tryptophan (5.6%) and lysine (5.2%) were less marked, except in ogi from malt, which showed 22.2 and 20.8% increases in tryptophan and lysine contents respectively. Apparent carbohydrate availability increased (by 17–93%) but energy value generally remained the same (highest increase 3.4%) when millet was converted to ogi. Conversion of grain to ogi reduced paste viscosity.

© 2002 Society of Chemical Industry
Collision‐induced fragmentations of the (M‐H)− parent anions of underivatized peptides: An aid to structure determination and some unusual negative ion cleavages
Authors: Bowie John H. , Brinkworth Craig S. , Dua Suresh
Published: October 2002

I.
Introduction
87

II.
Discussion
88

A. The Backbone Cleavages of (M‐H)− Parent Anions of Peptides
88

   1.  α‐ and β‐Backbone Cleavages
89

   2.  The β′ Cleavage
92

   3.  The Asp and Asn γ and δ Backbone Cleavages (Also Phe, Tyr, His, and Trp)
94

   4.  The δ‐ and γ‐Cleavages of Glu and Gln
96

   5.  Ser and Thr Cleavages: Side Chain and Backbone Fragmentations
99

       a.  The side chain cleavages
99

       b.  The backbone cleavage reactions of Ser and Thr
100

   6.  Other Backbone Cleavage Processes
102

Acknowledgments
105

References
105

This article describes the fundamental cleavage reactions of (M‐H)− anions of underivatized peptides that contain up to 25 amino acid residues. The experimental observations of these cleavages have been backed up by molecular modeling, generally at the AM1 level of theory. The basic cleavages are the ubiquitous α‐ and β‐backbone cleavage reactions, which provide information similar to that of the B and Y + 2 cleavages of MH+ ions of peptides. The residues Asp and Asn also effect cleavages of the backbone (called δ‐ and γ‐cleavages), by reactions initiated from side chain enolate anions, causing elimination reactions that cleave the backbone between the Asp (Asn) NC backbone bond. Glu and Gln also direct analogous δ‐ and γ‐cleavages of the backbone, but in this case the processes are initiated by attack of the side chain CO2− (CONH−) to form a lactone (lactam). Ser and Thr residues undergo characteristic fragmentations of the side chain. These processes, losses of CH2O (Ser) and MeCHO (Thr), convert these residues into Gly. In larger peptides, Ser and Thr can effect two backbone cleavage reactions, called γ‐ and ε‐processes. The C‐terminal CO2− (or CONH−) forms a hydrogen bond with the side chain OH (of Ser or Thr), placing the C‐terminal residue in a position where it may affect SN2 attack at the electrophilic backbone CH of Ser, with concomitant cleavage of the backbone. All of the above negative ion cleavages require the peptide backbone to be conformationally flexible. However, there is a backbone cleavage that requires the peptide to have an alpha‐helical conformation in order for the two reacting centers to approach. This cleavage is illustrated for the Glu23‐initiated backbone cleavage at Ile21 for the (M‐H)− anion of the antimicrobial peptide caerin 1.1. © 2002 Wiley Periodicals, Inc., Mass Spec Rev 21:87–107, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mas.10022
Design and synthesis of sialyl Lewisx mimics as E‐ and P‐selectin inhibitors
Authors: Kaila Neelu , Thomas IV Bert E.
Published: October 2002

The selectins are a family of cell‐adhesion proteins that mediate the rolling of leukocytes on activated endothelial cells through the recognition of the carbohydrate epitope sialyl Lewisx (sLex). Control of the leukocyte‐endothelial cell adhesion process may prove useful in cases where excess recruitment of leukocytes can contribute to acute diseases such as stroke and reperfusion injury and chronic diseases such as psoriasis and rheumatoid arthritis. The development of molecules that block the interactions between sLex and the selectins has become an active area of research. In this review, we will highlight the various approaches taken toward the development of sLex mimetics as antagonists of E‐ and P‐selectin, including the use of structural information about the selectins and their interactions with sLex that have been revealed through the use of NMR, protein crystallography and molecular modeling. © 2002 Wiley Periodicals, Inc. Med Res Rev, 22, No. 6, 566–601, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/med.10018
Existence of multiple positive solutions for −Δu−μ(u/∣x∣2)=u2*−1+σf(x)
Authors: Cheng Ting , Zhao Charles Xuejin
Published: October 2002

In this paper, we consider the semilinear elliptic problem

where Ω⊂ℝN (N⩾3) is a bounded smooth domain such that 0∈Ω, σ>0 is a real parameter, $$\mu < \overline{\mu } = (N - 2)^{2} /4$$ and f(x) is some given function in L∞(Ω) such that f(x)⩾0, f(x)≢0 in Ω. Some existence results of multiple solutions have been obtained by implicit function theorem, monotone iteration method and Mountain Pass Lemma. Copyright © 2002 John Wiley & Sons, Ltd.
Microstrip antenna controlled by p‐i‐n diodes: Influence of the bias current on the antenna efficiency
Authors: Laheurte J. M. , Tosi H. , Dubard J. L.
Published: October 2002

This Letter points out the drop in radiation efficiency observed in active microstrip antennas with switching capabilities for inadequate values of the bias current. For a frequency agile antenna based on p‐i‐n diodes, a trade‐off between the dc consumption of the diodes and the antenna gain is demonstrated. It is also shown that this type of integrated active antenna can be reasonably predicted by a simple resistor model of the diode in a TLM analysis. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 44–47, 2002; DOI 10.1002/mop.10226
TACC3 expression and localization in the murine egg and ovary
Authors: Hao Zhonglin , Stoler Mark H. , Sen Buer , Shore Amy , Westbrook Anne , Flickinger Charles J. , Herr John C. , Coonrod Scott A.
Published: October 2002

A protein spot cored from a silver‐stained two dimensional (2D) gel of germinal vesicle stage immature mouse oocytes was identified as Transforming Acidic Coiled Coil containing protein (TACC3) by tandem mass spectrometry. PCR amplification revealed two alternatively spliced forms, Tacc3a and Tacc3b, in mouse ovarian cDNA libraries. TACC3a encoded a 630 aa protein with a predicted mass of 70 kDa. It contained seven 24 aa repeats at the N‐terminus and two coiled‐coil domains at the C‐terminus. TACC3b encoded a 426 aa protein with a predicted mass of 49 kDa also containing two coiled coil domains, but lacking the 168 aa repeat region. In addition to homology to the TACC family members, murine TACC3 also showed 35.7% identity to the Xenopus protein, Maskin, a cytoplasmic polyadenylation element binding protein (CPEB)‐associated factor. Northern blot analysis demonstrated that TACC3a is abundantly expressed in adult testis and spleen and is moderately expressed in the ovary, heart, and lung, suggesting a wide tissue distribution. Both myc‐tagged TACC3a and TACC3b targeted to the cytoplasm of transiently transfected CV‐1 cells. In situ hybridization of mouse ovarian tissue sections displayed abundant expression of TACC3 specifically in the cytoplasm of growing oocytes, but not in primordial or atretic follicles. This pattern of expression suggests that TACC3 is expressed in ovarian cells undergoing active growth and development. Mol. Reprod. Dev. 63: 291–299, 2002. © 2002 Wiley‐Liss, Inc.
A mathematical model that predicts the force–frequency relationship of human skeletal muscle
Authors: Ding Jun , Wexler Anthony S. , Binder‐Macleod Stuart A.
Published: October 2002

In previous work we developed and validated a mathematical model that predicted force output from skeletal muscles subjected to six‐pulse stimulation trains under isometric condition. The current study investigated the model's ability to predict force responses to longer stimulation trains under both nonfatigued and fatigued conditions. Using the six‐pulse train model to predict the force produced by longer stimulation trains showed that the model was successful, but a modified parameter identification scheme was required. For most of the trains tested the model accounted for 95% of the variance in the experimental forces produced by stimulation trains, with mean frequencies from 12.5 to 100 HZ, train durations from 485 to 1000 ms, and number of pulses from 14 to 50 for both nonfatigued and fatigued muscles. The success of our mathematical model in predicting forces produced by stimulations with a wide range of frequencies, durations, and number of pulses implies great potential of the model for the identification of optimal activation patterns that should be used during functional electrical stimulation. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 477–485, 2002
Dominating sets for rectilinear center location problems with polyhedral barriers
Authors: Dearing P.M. , Hamacher H.W. , Klamroth K.
Published: October 2002

In planar location problems with barriers one considers regions which are forbidden for the siting of new facilities as well as for trespassing. These problems are important since they model various actual applications. The resulting mathematical models have a nonconvex objective function and are therefore difficult to tackle using standard methods of location theory even in the case of simple barrier shapes and distance functions. For the case of center objectives with barrier distances obtained from the rectilinear or Manhattan metric, it is shown that the problem can be solved in polynomial time by identifying a dominating set. The resulting genuinely polynomial algorithm can be combined with bound computations which are derived from solving closely connected restricted location and network location problems. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 647–665, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10038
Sparse matrix element topology with application to AMG(e) and preconditioning
Authors: Vassilevski Panayot S.
Published: October 2002

This paper defines topology relations of elements treated as overlapping lists of nodes. In particular, the element topology makes use of element faces, element vertices and boundary faces which coincide with the actual (geometrical) faces, vertices and boundary faces in the case of true finite elements. The element topology is used in an agglomeration algorithm to produce agglomerated elements (a non‐overlapping partition of the original elements) and their topology is then constructed, thus allowing for recursion. The main part of the algorithms is based on operations on Boolean sparse matrices and the implementation of the algorithms can utilize any available (parallel) sparse matrix format. Applications of the sparse matrix element topology to AMGe (algebraic multigrid for finite element problems), including elementwise constructions of coarse non‐linear finite element operators are outlined. An algorithm to generate a block nested dissection ordering of the nodes for generally unstructured finite element meshes is given as well. The coarsening of the element topology is illustrated on a number of fine‐grid unstructured triangular meshes. Published in 2002 by John Wiley & Sons, Ltd.
Distortion measure of trilinear mapping. Application to 3‐D grid generation
Authors: Branets L. V. , Garanzha V. A.
Published: October 2002

Distortion measures for polylinear mappings are investigated. It is shown that certain distortion measures satisfy the maximum principle which allows us to obtain upper bounds on the distortion measures for hexahedral cells and other types of elements widely used in the finite element method. These estimates allow to apply a maximum‐norm optimization technique for spatial mappings in the case of finite element grids consisting of hexahedra. A global hexahedral grid untangling procedure suggested earlier was tested on hard 3‐D examples demonstrating its ability to work in a black box mode and its high level of robustness. Copyright © 2002 John Wiley & Sons, Ltd.
Frequent FGFR3 mutations in urothelial papilloma
Authors: van Rhijn Bas W. G. , Montironi Rodolfo , Zwarthoff Ellen C. , Jöbsis Adriaan C. , van der Kwast Theo H.
Published: October 2002

Activating point mutations in the FGFR3 gene occur frequently in low‐grade and low‐stage bladder carcinomas, whereas they are rare in high‐grade carcinomas. This study investigates the incidence of FGFR3 mutations in 12 urothelial papillomas and 79 pTaG1 tumours which were regraded according to the 1998 WHO/ISUP classification system, resulting in 62 papillary urothelial neoplasms of low malignant potential (PUNs‐LMP) and 17 low‐grade papillary urothelial carcinomas (LG‐PUCs). FGFR3 mutation analysis of 21 ovarian Brenner tumours was also performed. Seventy‐seven cases were detected with a mutation in the FGFR3 gene. The mutations were exclusively found in bladder neoplasms. In urothelial papilloma, generally considered a benign lesion, 9/12 (75%) mutations were found. This report is the first to describe a genetic defect in urothelial papilloma. A comparable percentage of mutations was found in PUNs‐LMP (85%) and LG‐PUCs (88%). No mutations were found in matched normal DNA from bladder tumour patients. The mean follow‐up was 5.78 years (range 0.21–17.60 years). Five patients developed high‐grade papillary urothelial carcinoma from 2.5 to 12 years after first diagnosis. Two patients died of bladder cancer. The mean number of recurrences (recurrence rate) per year was 0.03, 0.21, and 0.46, respectively, for papilloma, PUN‐LMP, and LG‐PUC. Urothelial papilloma is a rare lesion with a benign natural behaviour compared with PUN‐LMP and LG‐PUC of the bladder, but from a molecular perspective, papillomas should be classified together with all well‐differentiated urothelial neoplasms. Copyright © 2002 John Wiley & Sons, Ltd.
Amphiphilic ABA triblock copolymer as surfactant in syntheses of microlatexes bearing cationic groups
Authors: Ni Pei‐Hong , Zhang Ming‐Zu , Zhuge Lan‐Jian , Fu Shou‐Kuan
Published: October 2002

Polystyrene microlatexes have been prepared by conventional emulsion polymerization with a novel amphiphilic water‐soluble ABA triblock copolymer, poly[2‐(dimethylamino)ethyl methacrylate]15‐b‐poly(propylene oxide)36‐b‐poly[2‐(dimethyl‐amino)ethyl methacrylate]15 (PDMAEMA15‐PPO36‐PDMAEMA15), as a polycationic emulsifier under acidic or neutral conditions. The ABA triblock copolymer was developed by oxyanion‐initiated polymerization in our laboratory. In this study, it acted well both as a polycationic polymeric surfactant to form block copolymeric micelles for emulsion polymerization and as a stabilizer to be anchored into the polystyrene microlatex or adsorbed onto its surface. The results obtained with various copolymer concentrations and different pH media showed that microlatex diameters decreased remarkably with increased concentration of this ABA triblock copolymeric emulsifier, but were not as much affected by the pH of media within the experimental range of 3.4–7.0. The observed difference of the particle sizes from transmission electron microscopy and dynamic light scattering measurements is discussed in terms of the effect of the absorbed surfactants and their electrical double layers. This difference has led to the formation of a cationic polyelectrolyte fringe on the surface of microspheres. The final microlatexes were characterized with respect to total conversion, particle diameter, and particle size distribution as well as colloidal stability. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3734–3742, 2002
Nickel(II) and palladium(II) complexes with α‐dioxime ligands as catalysts for the vinyl polymerization of norbornene in combination with methylaluminoxane, tris(pentafluorophenyl)borane, or triethylaluminum cocatalyst systems
Authors: Berchtold Bernd , Lozan Vasile , Lassahn Paul‐Gerhard , Janiak Christoph
Published: October 2002

Nickel(II) and palladium(II) complexes with α‐dioxime ligands dimethylglyoxime, diphenylglyoxime, and 1,2‐cyclohexanedionedioxime represent six new precatalysts for the polymerization of norbornene that can be activated with methylaluminoxane (MAO), the organo‐Lewis acid tris(pentafluorophenyl)borane [B(C6F5)3], and triethylaluminum (TEA) AlEt3. The palladium but not the nickel precatalysts could also be activated by B(C6F5)3 alone, whereas two of the three nickel precatalysts but none of the palladium systems are somewhat active with only TEA as a cocatalyst. It was possible to achieve very high polymerization activities up to 3.2 · 107 gpolymer/molmetal · h. With the system B(C6F5)3/AlEt3, the activation process can be formulated as the following two‐step reaction: (1) B(C6F5)3 and TEA lead to an aryl/alkyl group exchange and result in the formation of Al(C6F5)nEt3−n and B(C6F5)3−nEtn; and (2) Al(C6F5)nEt3−n will then react with the precatalysts to form the active species for the polymerization of norbornene. Variation of the B:Al ratio shows that Al(C6F5)Et2 is sufficient for high activation. Gel permeation chromatography indicated that it was possible to control the molar mass of poly(norbornene)s by TEA or 1‐dodecene as chain‐transfer agents; the molar mass can be varied in the number‐average molecular weight range from 2 · 103 to 9 · 105 g · mol−1. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3604–3614, 2002
Synthesis and crosslinking of polyethers that have mesogenic cores and propargyl groups
Authors: Bonet J. , Callau L. , Reina J. A. , Galià M. , Cádiz V.
Published: October 2002

We modified poly(epichlorohydrin) (PECH) with biphenyl carboxylic and naphthalene carboxylic acid derivatives which contains propargyloxy moieties. The linear polymers were characterized by NMR and IR spectroscopy, elemental analysis, DSC and TGA. We obtained only one side chain liquid crystalline. A smectic A mesophase of this biphenyl derivative was identified by DSC, light polarized optical microscopy and X‐ray diffraction. Thermal crosslinking of the aryl propargyl ether group via sigmatropic rearrangement took place while the material was in the isotropic phase. Partially curing this reactive liquid crystalline polymer resulted in the formation of an anisotropic elastomer when the curing was radically initiated in the range of mesophase stability. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3883–3892, 2002
Synthesis and characterization of luminescent copolymers containing iminodibenzyl and divinylbenzene chromophores
Authors: Wu Tzi‐Yi , Chen Yun
Published: October 2002

New conjugated copolymers containing alternating N‐hexyl‐3,8‐iminodibenzyl and divinylbenzene chromophores {poly(N‐hexyl‐3,8‐iminodibenzyl‐1,2‐ethenylene‐2,5‐dihexyloxy‐1,4‐phenylene‐1,2‐ethenylene) (P1) and poly[N‐hexyl‐3,8‐iminodibenzyl‐2,5‐bis(hexyloxy)cyanoterephthalidene] (P2)} were synthesized according to Wittig and Knoevenagel polymerization. A copolymer containing alternating carbazole and divinylbenzene derivatives {poly[9‐(2‐ethylhexyl)‐3,6‐carbazole‐1,2‐ethenylene‐2,5‐dihexyloxy‐1,4‐phenylene‐1,2‐ethenylene] (P3)} was also synthesized for comparison. The copolymers were soluble in common organic solvents such as tetrahydrofuran and toluene. Absorption and photoluminescence measurements revealed that cyano substitution at the vinylene moiety in P2 brought about a significant bathochromic shift and led to an electroluminescence color change from green to orange. The band edge energies of the copolymers were estimated from cyclic voltammograms and optical band gaps. P1 and P3 showed similar highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels, indicating that the electron‐donating abilities of the iminodibenzyl and carbazole chromophores were comparable. However, compared with those of P1 and P3, the HOMO and LUMO levels of P2 were greatly reduced because of conjugating and electron‐withdrawing CN groups. The threshold electric field of an Al/P1/ITO glass single‐layer light‐emitting diode was approximately 10 × 105 V/cm, whereas those for P2 and P3 were 7.5 and 16 × 105 V/cm, respectively. The electroluminescence emission maxima of P1–P3 were 498, 514, and 559 nm, respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3847–3857, 2002
Polymerization of vinyl ethers with transition‐metal catalysts: An examination of the stereoregularity of the formed polymers
Authors: Kawaguchi Takaaki , Sanda Fumio , Masuda Toshio
Published: October 2002

The polymerization of isobutyl vinyl ether (IBVE) and tert‐butyl vinyl ether (TBVE) was carried out with metallocene and nonmetallocene catalysts, and the stereoregularity of the formed polymers was examined with 13C NMR spectroscopy. IBVE afforded polymers with 63–68% dyad isotacticity by polymerization with mixtures of metallocene catalysts and methyl aluminoxane as a cocatalyst in toluene as a solvent. However, TBVE yielded polymers with 47–52% dyad isotacticity (21–28% triad isotacticity) under the same conditions, the isotacticity being lower than that of poly(isobutyl vinyl ether) (PIBVE). Nonmetallocene catalysts, including Ti, Zr, and Hf complexes with two phenoxy imine chelate ligands, provided PIBVE and poly(tert‐butyl vinyl ether) with 63–68 and 45–51% dyad isotacticity, respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3938–3943, 2002
Investigation of polycondensation through the copolycondensation of preformed oligomers and bisphenols by a two‐stage solution reaction with tosyl chloride, dimethylformamide, and pyridine
Authors: Higashi Fukuji , Sugishita Kanako
Published: October 2002

A two‐stage copolycondensation of an equimolar mixture of isophthalic acid and terephthalic acid first with a bisphenol (BP) and then with another BP was carried out with a tosyl chloride/dimethylformamide/pyridine condensing agent. When the preformed oligomers from a BP with no substituent or a methyl substituent were allowed to react with another BP comonomer containing polar SO2, CO, or Cl groups, the copolycondensation was significantly promoted. Such effects were absent with the unsubstituted BP and the methyl derivative. In addition, during the reaction of oligomers from BPs with polar groups, a similarly polar BP did not react so effectively, and the unsubstituted BP did not have any effect on the copolycondensation. On the basis of the sequence distributions for the resultant copolymers determined by 1H NMR, it was likely that the copolycondensation could be promoted when the second comonomers were randomly distributed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4024–4031, 2002
Effect of the sulfonic acid group on copolymers of aniline and toluidine with m‐aminobenzene sulfonic acid
Authors: Rao Palle Swapna , Sathyanarayana D. N.
Published: October 2002

This article describes the results of the preparation and characterization of self‐doped conducting copolymers of aniline and toluidine with m‐aminobenzene sulfonic acid. The copolymers have an intrinsic acid group that is capable of doping polyaniline. Spectroscopic, morphological, and electrical conductivity studies have provided insight into the structural and electronic properties of the copolymers. The differences in the properties of polyaniline and polytoluidine due to the sulfonic acid ring substituent on the phenyl ring are discussed. The scanning electron micrographs of the copolymers reveal regions of sharp‐edged, needle‐shaped structures, whereas the X‐ray diffraction patterns show that the copolymers are relatively more crystalline in nature. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4065–4076, 2002
Synthesis of optically active alicyclic polyimides from a chiral, nonracemic dianhydride
Authors: Kudo Kazuaki , Nonokawa Daigo , Li Jun , Shiraishi Shinsaku
Published: October 2002

Optically active alicyclic polyimides were prepared for the first time from (−)‐[1S*,5R*,6S*]‐3‐oxabicyclo[3.2.1]octane‐2,4‐dione‐6‐spiro‐3′‐(tetrahydrofuran‐ 2′,5′‐dione) [(−)‐DAn] via polycondensation with diamines and subsequent chemical or thermal imidization. The dianhydride (−)‐DAn was synthesized by an asymmetric Diels–Alder reaction of a chiral itaconic acid derivative as a key step. Colorless or slightly yellow flexible films were obtained for the (−)‐DAn‐derived polyimides {PI[(−)‐DAn]s}. PI[(−)‐DAn]s showed good solubility toward dipolar aprotic solvents and pyridine. For 1,4‐dioxane and chloroform, the optically active polyimides showed slightly better solubility than the corresponding polyimides prepared from rac‐DAn [PI(rac‐DAn)s]. PI[(−)‐DAn]s showed glass‐transition temperatures of 267–268 °C and 10% weight‐loss temperatures of 416–424 °C in nitrogen. These values were almost identical to those of PI(rac‐DAn)s. The circular dichroism spectra of PI[(−)‐DAn]s showed exciton coupling patterns indicating that to some extent these polyimides had a higher order structure in solution. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4038–4044, 2002
Controlling the mechanical properties of poly(L‐lactide– ε‐caprolactone) monofilament sutures by an acetone/water treatment
Authors: Uddin Ahmed Jalal , Katayama Norihiro , Ohkoshi Yutaka , Gotoh Yasuo , Nagura Masanobu
Published: October 2002

For monofilament biodegradable sutures fabricated from the L‐lactide–ε‐caprolactone (75/25) copolymer [P(LLA/CL)], there have been some concerns regarding their mechanical properties, such as the knot‐pull strength and stiffness. This article demonstrates the further potentiality of these sutures through improvements in those properties. With the aim of diminishing the molecular orientation, particularly in the suture surface region, we adopted an expedient method to treat P(LLA/CL) sutures with an acetone/water mixture, using different times and time patterns. The changes in the molecular orientation distributions across the suture cross sections were characterized by the specific index of birefringence measured with an interference microscope. The crystal orientations, knot‐pull strengths, tensile strengths, and bending rigidity were measured. The conformational changes in suture breaking during knot‐pull tests were analyzed with high‐speed‐video observations. Morphological analyses of the fractural surfaces were performed with scanning electron microscopy. The knot‐pull strength tended to rise, in comparison with that of untreated samples, up to a certain treatment time and was accompanied by a minimal decrement of the tensile strength. The knot‐pull strength did not show an increasing trend with further treatment, whereas the tensile strength declined remarkably. The birefringence, crystal orientation, bending rigidity, fractured surface analysis, and high‐speed‐video observations revealed molecular disorientation mainly in the filament outer layers for that particular treatment causing the sutures to be considerably softer. The suture softness played a role in changing the deformation behavior of the knot when a load was applied and caused the knot‐pull strength to rise. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2449–2462, 2002
Effect of structural characteristic on physical properties of copolyesters from poly(ethylene terephthalate) oligomer and polycaprolactone
Authors: Lim Kyung Yul , Kim Byoung Chul , Yoon Kee Jong
Published: October 2002

A series of poly(ethylene terephthalate/polycaprolactone) (PET/PCL) copolyesters were prepared by adding PCL with a weight‐average molecular weight of 40,000 to the PET oligomer during polycondensation, and the composition and physical properties of the copolymers were investigated. In the case of copolyesters containing caprolactone (CL) units less than 26 mol %, the melting and crystallization temperatures were decreased with increasing CL content. They exhibited wide‐angle X‐ray diffraction (WAXD) patterns similar to PET. However, the variation of d‐spacing on the WAXD pattern suggested that a small amount of CL could be included into the crystal of ethylene (ET) because of strong hydrogen bonding between crystallizable ET blocks. In the copolyesters containing CL components higher than 38 mol %, they exhibited thermal behavior and WAXD patterns typical of amorphous random copolymers. The copolyester composition has a decisive effect on the rheological properties. The copolyesters with CL contents higher than 38 mol % exhibited a viscosity behavior similar to Bingham fluid, although the copolyesters with CL contents lower than 26 mol % exhibited a Newtonian flow behavior similar to PET. In addition, the value of the loss tangent of the copolyester melts notably decreased with an increasing CL content, and the bulk exhibited rubberlike behavior. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2552–2560, 2002
Studies on the equilibrium among poly(sodium 4‐styrenesulfonate), Cu2+, and iminodiacetic acid by ultrafiltration at constant ionic strength
Authors: Moreno‐Villoslada I. , Muñoz C. , Rivas B. L.
Published: October 2002

The ultrafiltration technique evaluates the interactions of water‐soluble polymers with metal ions. Aqueous solutions containing poly(sodium 4‐styrenesulfonate) (PSS), Cu(NO3)2, NaNO3, and iminodiacetic acid (IDAA) are examined by this technique. Cu2+ undergoes complex formation with IDAA and intreracts electrostatically with PSS. On the other hand, Na+ ions are in competition with Cu2+ for the electrostatic binding to PSS. The solutions are ultrafiltered keeping the ionic strength constant, so their compositions are allowed to change continuously. The concentration of Cu2+ bound to the polymer showed an exponential decay during filtration. The concentration of Cu2+ bound to the polymer before ultrafiltration is calculated by extrapolation. The concentration of the different species in solution is proposed as a function of the filtration factor. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2587–2593, 2002
Relaxation behavior of poly(ethylene terephthalate)/poly(ethylene naphthalene 2,6‐dicarboxylate) blends prepared by cryogenic blending
Authors: Denchev Z. , Ezquerra T. A. , Nogales A. , Ŝics I. , Alvarez C. , Broza G. , Schulte K.
Published: October 2002

A method including cryogenic grinding, melt pressing from the molten state, and quenching was used to prepare blends of poly(ethylene terephthalate) (PET) and poly(ethylene naphthalene 2,6‐dicarboxylate) (PEN) in which the two phases were highly dispersed. The effect of melt‐pressing times on the thermal properties and relaxation behavior of PET/PEN films were characterized with differential scanning calorimetry and dielectric spectroscopy. For short melt‐pressing times, two glass‐transition, two crystallization, and two melting peaks were observed, indicating the presence of PET‐rich and PEN‐rich phases in these blends. Longer melt‐pressing times revealed a single glass transition and a single α‐relaxation process, showing that PET–PEN block copolymers were likely to be formed during the melt pressing. The experimental findings were examined in terms of the transesterification reactions between the blend components, as revealed by 1H NMR measurements. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2570–2578, 2002
Invasive mechanical ventilation for acute respiratory failure in children with cystic fibrosis: Outcome analysis and case‐control study
Authors: Berlinski Ariel , Fan Leland L. , Kozinetz Claudia A. , Oermann Christopher M.
Published: October 2002

The outcome for cystic fibrosis (CF) patients requiring intubation and invasive mechanical ventilation (IMV) due to acute respiratory failure (ARF) has been poor. Mortality rates have been reported as high as 60–90%. However, a review of mortality in children has not been published in 20 years. Our objectives were to study outcomes in CF patients requiring IMV due to ARF between 1988–1998, compare recent outcomes with those previously reported, and identify risk factors associated with poor outcome. We additionally attempted to identify factors suggesting an increased risk of developing ARF requiring IMV. A retrospective cohort study design was used, comparing IMV survivors and nonsurvivors with a nested case‐control study to identify risk factors for ARF leading to IMV. All patients cared for at our Center who required IMV for ARF between 1988–1998 were identified. Outcome, age, steroid use, forced vital capacity (FVC), forced expired volume in 1 sec (FEV1), microbiology, nutritional status, CF‐related diabetes (CFRD), liver dysfunction, and history of major hemoptysis (HEM) or pneumothorax (PTX) were recorded. Cases were matched for gender and age with CF controls identified through a clinical database.

Thirty‐eight episodes of IMV due to ARF were reported in 33 patients. Three subjects underwent IMV on two or more occasions, but only the first episode was included in analysis. Older age was the only factor that was significantly associated with mortality: 9 subjects were <5 years of age (mortality, 22%), while 24 were 5–34 years old (mortality, 75%) (P = 0.013). There was an increased risk of having an episode of ARF requiring IMV in malnourished subjects (OR = 4.2; 95% CI = 1.66–10.51) and in those with a history of HEM (OR = 6.3; 95% CI = 1.75–22.65).

Infants and young children with CF requiring IMV due to ARF have a favorable prognosis, whereas those ≥5 years of age suffer significantly higher mortality. Malnutrition and a history of HEM are important risk factors for having an episode of ARF requiring IMV. Pediatr Pulmonol. 2002; 34:297–303. © 2002 Wiley‐Liss, Inc.
Influence of lipopolysaccharide exposure on airway function and allergic responses in developing mice
Authors: Cochran John R. , Khan Amir M. , Elidemir Okan , Xue Hasen , Cua Beatrize , Fullmer Jason , Larsen Gary L. , Colasurdo Giuseppe N.
Published: October 2002

Exposure to endotoxin has been associated with an exacerbation of asthmatic responses in humans and animal models. However, recent evidence suggests that microbial exposure in early life may protect from the development of asthma and atopy. In this study, we sought to evaluate the effects of lipopolysaccaride (LPS) on airway function in developing mice. In addition, we evaluated the influence of LPS on subsequent allergen sensitization and challenge. Under light anesthesia, 2–3‐week‐old Balb/c mice received a single intranasal instillation of LPS or sterile physiologic saline. Measurements of airway function were obtained in unrestrained animals, using whole‐body plethysmography. Airway responsiveness was expressed in terms of % enhanced pause (Penh) increase from baseline to aerosolized methacholine (Mch). In additional studies, we assessed the functional and cellular responses to ovalbumin sensitization and challenge following prior exposure to LPS.

We found that exposure to LPS induced transient airway hyperresponsiveness to Mch. These functional changes were associated with the recruitment of neutrophils and lymphocytes into the bronchoalveolar lavage (BAL) fluid. Airway responsiveness after allergen sensitization and challenge was decreased by prior exposure to LPS. The analysis of BAL cells and cytokines (interferon‐γ and interleukin‐4) did not reveal alterations in the overall Th1/Th2 balance.

Our findings suggest that LPS leads to airway hyperresponsiveness in developing mice, and may protect against the development of allergen‐driven airway dysfunction. Pediatr Pulmonol. 2002; 34:267–277. © 2002 Wiley‐Liss, Inc.
Inhibition of orthotopic growth and metastasis of androgen‐sensitive human prostate tumors in mice by bioactive soybean components
Authors: Zhou Jin‐Rong , Yu Lunyin , Zhong Ying , Nassr Rena L. , Franke Adrian A. , Gaston Sandra M. , Blackburn George L.
Published: October 2002

BACKGROUND

Systematic analysis of the influence of diet on the initiation and progression of prostate cancer is often difficult in human populations, for which dietary variables overlap a diversity of genetic backgrounds and social behaviors. Animal models that emulate human prostate cancer allow experimental analysis of the mechanisms of action of nutritional agents that show anti‐prostate cancer activity.

METHODS

We have used an orthotopic implant model to characterize the in vivo response of androgen‐sensitive LNCaP prostate tumors to three well‐characterized soy dietary supplements: isoflavone depleted soy protein, soy phytochemical concentrate (SPC), and genistin.

RESULTS

In male SCID mice orthotopically implanted with the androgen‐sensitive human prostate cell line LNCaP, dietary supplements of soy protein, genistin, and SPC reduced primary tumor weight by 42% (P = 0.07), 57% (P < 0.05) and 70% (P < 0.005), respectively. All three soy supplements significantly increased tumor apoptosis and decrease microvessel density, with no significant change in tumor proliferation. Each supplement produced a distinct serum androgen response, with genistin producing the greatest decrease in total serum testosterone and dihydrotestosterone (DHT) (P < 0.05) and the greatest increase in testosterone to DHT ratio (P < 0.05) and soy protein the greatest decrease in bioactive androgen (P < 0.05). Only SPC significantly inhibited metastases to lymph nodes and lungs, and only SPC produced a significant increase in tumor p53 expression.

CONCLUSION

Taken together, these data suggest that the anti‐prostate cancer activity of dietary soy protein, soy phytochemicals, and genistin use different molecular pathways. In addition, we have demonstrated that this animal model can be used in the design of dietary strategies for prostate cancer prevention and therapy. Prostate 53: 143–153, 2002. © 2002 Wiley‐Liss, Inc.
Rebuilt 3D structure of the chloroplast f1 ATPase–tentoxin complex
Authors: Minoletti Claire , Santolini Jérôme , Haraux Francis , Pothier Joël , André François
Published: October 2002

The F1 part of the chloroplast H+ adenosine triphosphate (ATP)‐synthase (CF1) strongly interacts with tentoxin, a natural fungous cyclic tetrapeptide known to inhibit the chloroplast enzyme and not the mammalian mitochondrial enzyme. Whereas the synthesis or the hydrolysis of ATP requires the stepwise rotation of the protein rotor γ within the (αβ)3 crown, only one molecule of tentoxin is needed to fully inhibit the complex. With the help of an original homology modeling technique, based on robust distance geometry protocols, we built a tridimensional model of the α3β3γ CF1 subcomplex (3200 residues), in which we introduced three different nucleotide occupancies to check their possible influence on the tentoxin binding site. Simultaneous comparison of three available high‐resolution X‐ray structures of F1, performed with a local structural alignment search tool, led to characterizing common structural blocks and the distorsions experienced by the complex during the catalytic turnover. The common structural blocks were used as a starting point of the spinach CF1 structure rebuilding. Finally, tentoxin was docked into its putative binding site of the reconstructed structure. The docking method was initially validated in the mitochondrial enzyme by its ability to relocate nucleotides into their original position in the crystal. Tentoxin binding was found possible to the two α/β interfaces associated with the empty and adenosine diphosphate (ADP)‐loaded catalytic sites, but not to the one associated with the ATP‐loaded site. These results suggest a mechanism of CF1 inhibition by one molecule of tentoxin, by the impossibility of the α/β interface bearing tentoxin to pass through the ATP‐loaded state. Proteins 2002;49:302–320. © 2002 Wiley‐Liss, Inc.
Effect of quercetin on plasma extravasation in rat CNS and dura mater by ACE and NEP inhibition
Authors: Cyrino Luiz A. R. , Cardoso Ronie C. F. , Hackl Luciane P. N. , Nicolau Mauro
Published: October 2002

The effects of quercetin on substance P‐induced plasma protein extravasation (PE) in the rat dura mater, cerebellum, olfactory bulb and cortex and also its modulation by endopeptidases, angiotensin‐converting enzyme (ACE) and neutral endopeptidase (NEP) were studied. PE was assessed by photometric measurement of extravasated Evans blue. Substance P (SP) and NEP or ACE inhibitors increased the PE in dura mater. Pretreatment with captopril or phosphoramidon potentiated PE induced by SP in the dura mater and cerebellum, respectively. Quercetin increased the PE in the dura mater, cerebellum and cortex. Further results suggested that the PE induced by SP in the dura mater was enhanced by pretreatment with quercetin, similar to that observed with selective peptidase inhibitors. Quercetin‐stimulated extravasation in all tissues was abolished by NK‐1 receptor blockade. These results suggest that quercetin increases PE in the dura mater and CNS tissues by inhibiting NEP and/or ACE, showing that the effect induced in the dura mater, cerebellum and cortex occurs through endogenous SP accumulation. Copyright © 2002 John Wiley & Sons, Ltd.
Antimicrobial activity of some species of the family Combretaceae
Authors: Elegami A. A. , El‐Nima E. I. , Tohami M. S. El , Muddathir A. K.
Published: October 2002

Forty eight extracts of four plants of the family Combretaceae were screened for antibacterial activity against standard organisms as well as clinical isolates. The extracts in different solvent systems showed high activity against both standard organisms and clinical isolates. Phytochemical screening revealed that the plants were very rich in tannins to which antibacterial activity may be attributed. Copyright © 2002 John Wiley & Sons, Ltd.
Self‐energy operator and self‐energy fields in many‐body systems: Liouvillian approach
Authors: Bochicchio Roberto C. , Grinberg Horacio
Published: October 2002

An explicit definition for the self‐energy field operator and the self‐energy fields obtained from an average of the associated operator within the algebraic formalism of superoperators is presented. It stems from the formal expansion of the many‐body propagator equations of motion hierachy in quantum many‐body systems within the scenario of the Liouvillian decoupling scheme developed in previous works. An essential theoretical property of such fields for the complete expansion of the propagator to any order in the interaction potential is shown. This states that the interaction potential to a given order only depends on one q‐reduced density matrix. The contraction order q of the density matrix depends on both the nature of the operators defining the propagator and the actual order of the expansion. This result is rigorous regarding infinite summation of the irreducible terms of the self‐energy fields and provides a direct way to estimate the extent to which many‐body effects are involved in successive approximations, i.e., truncation of the excitation level given by the reference state throughout the reduced density matrix and the expansion of the propagator. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
Conformations of the S and S homocyclic radical cations
Authors: Cioslowski Jerzy , Szarecka Agnieszka , Moncrieff David
Published: October 2002

According to both UB3LYP/6‐311G* and UMP2/6‐311G* calculations, the S homocyclic radical cation exists in only one conformer of Cs symmetry that undergoes a facile pseudorotation through a C2 transition state. A structure with D3d symmetry is predicted to be the global minimum for the S species. The current study uncovers the gradual transition from the conformational simplicity of smaller homocyclic sulfur cations, for which the rigidity of the rings apparently translates into a relatively weak influence of electron correlation effects on their relative energetics and geometries, to the conformational complexity of larger species, for which significant discrepancies between the predictions of different electronic structure methods are observed. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
An ab initio/Rice–Ramsperger–Kassel–Marcus study of photodissociation of carbonyl cyanide
Authors: Lee H. Y. , Mebel A. M. , Lin S. H.
Published: October 2002

The geometries and vibrational frequencies of the parent molecule, intermediates, transition state, and products involved in the photochemical decay of carbonyl cyanide NC–C(O)–CN have been studied by ab initio calculations at the MP2/6‐311G* level. The energies of various species have been refined using the modified Gaussian‐2 [G2M(MP2)] method. The molecular parameters and energetics derived from the ab initio calculations were used to compute microcanonical rate constants of all possible reaction steps of photodissociation of the carbonyl cyanide employing the conventional and variational RRKM theory and to obtain the product branching ratios. The results show that the radical decay, CO(CN)2+ hν→OCCN/OCNC+CN, is dominant (86.14% and 13.85% for OCCN and OCNC, respectively), while the molecular decay, CO(CN)2→CO+NCCN, gives only a trace amount of the products. Whereas the computed radical product yields qualitatively agree with those measured in experiment (Scheld, H. A., et al. J Chem Phys 1999, 111, 923), the calculated branching ratio for the molecular decay channel underestimates the experimental value of ∼6%. This deviation may be attributed to the deficiencies in the variational RRKM treatment of the radical decay rate constants and/or to some nonstatistical behavior of the system which enhances the molecular decay. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Use of fast Fourier transform computational methods in electron scattering
Authors: Ritchie Burke , Riley Merle E.
Published: October 2002

Two methods are studied for elastic electron–atom and electron–molecule elastic scattering. The first is a numerical solution of the time‐dependent Schrödinger equation suitable for continuum states; the second is a convergent modified Born series of the time‐independent integral Schrödinger (Lippmann–Schwinger) equation. Both methods make use of fast Fourier transform (FFT) computational methods in order to bring the free‐electron Green's function into diagonal form. A large advantage of this methodology is the ability to describe scattering from targets of any geometry and at any collision energy by using 3D FFTs to accomplish the labor of evaluating spatially complex collision kernels. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002