bluuebunny/crossref_metadata_2025 huggingface dataset:
One‐step synthesis of polycarbonates bearing pendant carboxyl groups by lipase‐catalyzed ring‐opening polymerization
Authors: Al‐Azemi Talal F. , Bisht Kirpal S.
Published: August 2002

The ring‐opening polymerization of a monomer containing a free carboxylic acid group is reported for the first time. The monomer, 5‐methyl‐5‐carboxyl‐1,3‐dioxan‐2‐one (MCC), was copolymerized with trimethylene carbonate (TMC) in an enzymatic ring‐opening polymerization conducted in bulk at 80 °C. The low‐melting TMC comonomer also solubilized the high‐melting MCC monomer, allowing for solvent‐free polymerizations. Six commercially available lipases were screened, and Candida antarctica lipase‐B (Novozym‐435) and Pseudomonas cepacia lipase were selected to catalyze the copolymerization because of their higher monomer conversions. Higher molecular weight polymers (weight‐average molecular weight = 7800–9200) were prepared when Novozym‐435 was used, with less MCC incorporated into the copolymer than used in the monomer feed. However, Pseudomonas cepacia lipase showed good agreement between the molar feed ratios and the molar composition, but the molecular weights (weight‐average molecular weight = 3600–4800) were lower than those obtained when Novozym‐435 was used. 13C NMR spectral data were used for microstructural analysis, which suggested the formation of random, linear, and pendant carboxylic acid groups containing polycarbonates with hydroxyl groups at both chain ends. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1267–1274, 2002
Synthesis and properties of new organosoluble and alternating aromatic poly(ester‐amide‐imide)s with pendant phosphorus groups
Authors: Liou Guey‐Sheng , Hsiao Sheng‐Huei
Published: August 2002

New phosphorus‐containing aromatic diesteramines, 1,4‐bis(4‐aminobenzoyloxy)‐2‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉oxaphosphorin‐6‐yl)naphthalene (p‐3) and 1,4‐bis(3‐aminobenzoyloxy)‐2‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉oxaphosphorin‐6‐yl)naphthalene (m‐3), were synthesized by the reaction of 2‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉oxaphosphorin‐6‐yl)‐1,4‐naphthalenediol with 4‐nitrobenzoyl chloride and 3‐nitrobenzoyl chloride, respectively, followed by catalytic reduction. Two series of phosphorus‐containing aromatic poly(ester‐amide‐imide)s with inherent viscosities of 0.94–2.00 and 0.41–0.56 dL/g were prepared via low‐temperature solution polycondensation from p‐3 and m‐3, respectively, with three imide ring‐preformed diacid chlorides. All the poly(ester‐amide‐imide)s were amorphous and readily soluble in many organic solvents such as N,N‐dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidone (NMP). Transparent, tough, and flexible films of these polymers were cast from DMAc or NMP solutions. Their casting films possessed a tensile strength range of 118–181 MPa, an elongation to break of 5–11%, and an initial modulus range of 2.41–4.46 GPa. They had useful levels of thermal stability associated with relatively high glass‐transition temperatures (264–286 °C) and 10% weight‐loss temperatures in excess of 450 °C in nitrogen or air. The limiting oxygen indices of these polymers were 41–46. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1786–1799, 2001
Cobalt‐mediated catalytic chain‐transfer polymerization (CCTP) in water and water/alcohol solution
Authors: Haddleton David M. , Depaquis Estelle , Kelly Elizabeth J. , Kukulj Dax , Morsley Stuart R. , Bon Stefan A. F. , Eason Michael D. , Steward Andrew G.
Published: August 2002

This article describes the use of cobalt‐mediated catalytic chain transfer in aqueous solution under fed conditions for the preparation of macromonomers of acidic, hydroxy, and zwitterionic functional monomers. Use of a batch reaction leads to hydrolysis of catalyst, a mixture of mechanisms and poor control of the reaction. A feed process is described that adds catalyst as a solution in monomer over the course of the reaction. The feed process is applied to a range of monomers of methacrylic acid (2), 2‐aminoethyl methacrylate hydrochloride (3), 2‐hydroxyethyl methacrylate (4), 2‐methacryloxyethyl phosphoryl choline (5), glycerol monomethyl methacrylate (6), and 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐D‐glucofuranose (7). Use of the feed process for water‐soluble monomers in conjunction with 1 as a catalytic chain‐transfer agent gives high‐conversion, > 90%, water‐soluble macromonomers. The number‐average molecular mass (Mn was determined by integration of the 1H NMR spectrum comparing the vinylic end group with the remainder of the backbone. Pseudo‐Mayo plots were constructed by measuring the Mn at high conversion as a function of [monomer]/[catalyst] to give observed chain‐transfer constants of 1120, 958, and 1058 for 4, 6, and 2, respectively. All products were obtained as relatively high‐solid, homogeneous, low‐viscosity aqueous solutions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2378–2384, 2001
Synthesis and polymerization of amphiphilic methacrylates containing permanent dipole azobenzene chromophores
Authors: Altomare Angelina , Ciardelli Francesco , Gallot Bernard , Mader Michele , Solaro Roberto , Tirelli Nicola
Published: August 2002

New amphiphilic photochromic methacrylates with the structures of 4‐[ω‐methacryloyloxyoligo(ethyleneglycol)]‐4′‐cyanoazobenzene (MEn) and 4‐methacryloyloxy‐4′‐{2‐cyano‐3‐oxy‐3‐[ω‐methoxyoligo(ethyleneglycol)]prop‐1‐en‐1‐yl}azobenzene (MEnMe) and oligo(oxyethylene) segments of different lengths were synthesized. These methacrylates were characterized by the presence of permanent dipole azobenzene chromophores and hydrophilic oligo (oxyethylene) segments. The methacrylates were obtained with six‐step and five‐step synthetic sequences, respectively, in 12–47% overall yields. The radical polymerization of the MEn monomers afforded a 50% yield of the corresponding polymers as orange solids with a number‐average molecular weight of about 40 kD. No solid polymer was obtained from the radical polymerization of the MEnME compounds. Two‐dimensional NMR spectra allowed the unequivocal assignment of the NMR signals and demonstrated a significant contribution of internal charge transfer to the electronic distribution of the azobenzene chromophore. Relaxation time measurements confirmed that the flexible polyether segment effectively decoupled photochromic groups from the polymer backbone. Optical microscopy, differential scanning calorimetry analysis, and X‐ray diffraction data demonstrated the presence of interdigitated smectic mesophases. The stability of mesophases showed a significant dependence on the chemical structure of the analyzed compounds. The glass‐transition temperatures of the polymers were rather low because of the plasticizing effect of the spacers. The monomers and polymers were used for the deposition of Langmuir films and Langmuir–Blodgett–Kuhn multilayers. A strong influence of the macromolecular structure on the film properties was observed. The photoresponsive properties of monomers and polymers were investigated with irradiation at different wavelengths. Isomerization kinetics were independent of both molecular weight and spacer length. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2957–2977, 2001
Lateral thermal expansion of cellulose Iβ and IIII polymorphs
Authors: Wada Masahisa
Published: August 2002

Measurements of the thermal expansion coefficients (TECs) of cellulose crystals in the lateral direction are reported. Oriented films of highly crystalline cellulose Iβ and IIII were prepared and then investigated with X‐ray diffraction at specific temperatures from room temperature to 250 °C during the heating process. Cellulose Iβ underwent a transition into the high‐temperature phase with the temperature increasing above 220–230 °C; cellulose IIII was transformed into cellulose Iβ when the sample was heated above 200 °C. Therefore, the TECs of Iβ and IIII below 200 °C were measured. For cellulose Iβ, the TEC of the a axis increased linearly from room temperature at αa = 4.3 × 10−5 °C−1 to 200 °C at αa = 17.0 × 10−5 °C−1, but the TEC of the b axis was constant at αb = 0.5 × 10−5 °C−1. Like cellulose Iβ, cellulose IIII also showed an anisotropic thermal expansion in the lateral direction. The TECs of the a and b axes were αa = 7.6 × 10−5 °C−1 and αb = 0.8 × 10−5 °C−1. The anisotropic thermal expansion behaviors in the lateral direction for Iβ and IIII were closely related to the intermolecular hydrogen‐bonding systems. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1095–1102, 2002
Brittle–ductile transition in high‐density polyethylene/glass‐bead blends: Effects of interparticle distance and temperature
Authors: Yuan Qiang , Jiang Wei , Zhang Huixuan , Yin Jinghua , An Lijia , Li R. K. Y.
Published: August 2002

The toughness of high‐density polyethylene (HDPE)/glass‐bead blends containing various glass‐bead contents as a function of temperature was studied. The toughness of the blends was determined from the notch Izod impact test. A sharp brittle–ductile transition was observed in impact strength–interparticle distance (ID) curves at various temperatures. The brittle–ductile transition of HDPE/glass‐bead blends occurred either with reduced ID or with increased temperature. The results indicated that the brittle–ductile‐transition temperature dropped markedly with increasing glass‐bead content. Moreover, the correlation between the critical interparticle distance (IDc) and temperature was obtained. Similar to the IDc of polymer blends with elastomers, the IDc nonlinearly increased with increasing temperature. However, this was the first observation of the variation of the IDc with temperature for polymer blends with rigid particles. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1855–1859, 2001
Chain dimensions and transport coefficients of sodium poly(isoprenesulfonate) in aqueous sodium chloride
Authors: Chisaka Shunsuke , Norisuye Takashi
Published: August 2002

Sodium poly(isoprenesulfonate) (NaPIS) fractions consisting of 1,4‐ and 3,4‐isomeric units (0.44:0.56) and ranging in molecular weight from 4.9 × 103 to 2.0 × 105 were studied by static and dynamic light scattering, sedimentation equilibrium, and viscometry in aqueous NaCl of a salt concentration (Cs) of 0.5‐M at 25 °C. Viscosity data were also obtained at Cs = 0.05, 0.1, and 1 M. The measured z‐average radii of gyration 〈S2〉z1/2, intrinsic viscosities [η], and translational diffusion coefficients D at Cs = 0.5‐M showed that high molecular weight NaPIS in the aqueous salt behaves like a flexible chain in the good solvent limit. On the assumption that the distribution of 1,4‐ and 3,4‐isomeric units in the NaPIS chain is completely random, the [η] data for high molecular weights at Cs = 0.5 and 1 M were analyzed first in the conventional two‐parameter scheme to estimate the unperturbed dimension at infinite molecular weight and the mean binary cluster integral. By further invoking a coarse‐graining of the NaPIS molecule, all the [η] and D data in the entire molecular weight range were then analyzed on the basis of the current theories for the unperturbed wormlike chain combined with the quasi‐two‐parameter theory. It is shown that the experimental 〈S2〉z, [η], and D are explained by the theories with a degree of accuracy similar to that known for uncharged linear flexible homopolymers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2071–2080, 2001
Oncologists' reactions to cancer patients' verbal cues
Authors: Butow P.N. , Brown R.F. , Cogar S. , Tattersall M.H.N. , Dunn S.M.
Published: August 2002

The diagnosis and treatment of cancer cause considerable psychological distress and morbidity. Consequently, cancer patients have high needs for informational and emotional support and doctors vary in their ability to recognise and address these needs. This study investigated patients' attempts to gain informational and emotional support through the use of verbal cues. The sample consisted of 298 patients with heterogeneous cancers, seeing one of five medical and four radiation oncologists for the first time. Sociodemographic variables and patient anxiety and satisfaction ratings were obtained. Transcripts of the audiotaped consultations were analysed and question‐asking, use of indirect cues, cue type (informational or emotional), content categories in which questions and cues occurred and doctor response (responded to or not responded to), were recorded. Patients asked a median of 11 questions and gave two cues per consultation, usually during treatment discussions. Patients gave, and doctors responded to, more informational than emotional cues. Patients gave significantly more informational cues during longer consultations. Younger and female patients gave more cues for emotional support and asked questions. No demographic variables were associated with the doctors' response to emotional and informational cues; however, consultations in which more informational cues were responded to were shorter, even when controlling for the number of cues given. Satisfaction with the consultation and patient anxiety were unaffected by doctors' responses to cues. Overall, results showed that doctors effectively identify and respond to the majority of informational cues; however, they are less observant of and able to address cues for emotional support. Cues can be addressed without lengthening the consultation or increasing patient anxiety. Copyright © 2002 John Wiley & Sons, Ltd.
Ethnic differences in quality of life among early breast and prostate cancer survivors
Authors: Gotay Carolyn Cook , Holup Joan L. , Pagano Ian
Published: August 2002

This study assessed quality of life (QOL) in recently diagnosed breast and prostate cancer patients of European American and Asian Pacific Islanders (specifically, individuals of Filipino, Japanese, and Native Hawaiian ancestry) to investigate whether QOL varied according to ethnicity and the relative importance of ethnicity as a predictor of QOL. Participants were identified through consecutive registrations on the Hawaii Tumor Registry, based on a diagnosis of breast or prostate cancer 4–6 months previously. QOL was measured by the QLQ‐C30, a standardized questionnaire widely used in cancer patient populations. Two hundred and twenty‐seven individuals participated (101 prostate and 126 breast cancer patients). QOL was similar across ethnic groups in most areas of QOL. However, differences were found in several areas, all in the direction of Filipino patients reporting worse outcomes. Hierarchical stepwise regressions supported the importance of ethnicity, controlling for clinical and demographic predictors. We conclude that additional research is needed to understand the relationship between ethnicity and QOL in cancer survivors. Copyright © 2002 John Wiley & Sons, Ltd.
Late presentation of Bochdalek hernia: Clinical and radiological aspects
Authors: Öztürk Haluk , Karnak Ibrahim , Sakarya Mehmet Turgay , Çetinkurşun Salih
Published: August 2002

Three infants with late presentation of Bochdalek hernia are presented. The presenting symptoms were cough, intermittent vomiting, dyspnea, and cyanosis. Initial diagnoses of isolated paravertebral mass and foreign material aspiration were made in two infants, based on plain chest x‐ray findings and history of the patients. Further radiological investigations, such as contrast upper gastrointestinal series or enema, computerized tomography, and magnetic resonance imaging of the chest, suggested the diagnosis of Bochdalek hernia. The hernia was found on the left side in two patients and on the right side in one. At operation, the stomach, small intestine, and spleen were found as herniated organs in one patient, ascending colon in one, and all of the small intestine together with ascending colon in the other.

A congenital diaphragmatic defect should be suspected in every child presenting with unusual respiratory or gastrointestinal symptoms and with abnormal chest x‐ray findings. The radiological findings vary greatly from one case to another, and even in the same case at different times because of differences in herniated organs and intermittent spontaneous reduction. The possibility of congenital diaphragmatic hernia should be kept in mind to avoid a wrong diagnosis, undue delay in diagnosis, and inappropriate treatment. Pediatr Pulmonol. 2001; 31:306–310. © 2001 Wiley‐Liss, Inc.
Relationship between bronchial hyperresponsiveness and development of asthma in children with chronic cough
Authors: Nishimura Hideko , Mochizuki Hiroyuki , Tokuyama Kenichi , Morikawa Akihiro
Published: August 2002

To evaluate the relationship between bronchial hyperresponsiveness (BHR) and the development of asthma in children with chronic cough, we performed methacholine inhalation challenges and transcutaneous oxygen pressure (tcPO2) measurements in 92 children with chronic cough aged from 1–13 years (55 boys and 37 girls; mean, 5.3 years) and followed them for  ≥ 10 years. Forty‐four age‐matched children with asthma (24 males and 20 females; mean, 6.5 years) and 44 age‐matched children without cough or asthma served as controls (18 males and 26 females; mean, 4.6 years). Consecutive doubling doses of methacholine were inhaled until a 10% decrease in tcPO2 from baseline was observed. The cumulative dose of methacholine at the inflection point of the tcPO2 record (Dmin‐PO2) was considered to represent hyperresponsiveness to inhaled methacholine.

After 10 years or more of follow‐up, 60 of the 92 subjects with cough answered our questionnaire, and 27/60 had been diagnosed with asthma. There was a statistical difference in Dmin‐PO2 between the children who presented with chronic cough originally and who developed asthma (asthma‐developed group) and those who did not develop asthma (asthma‐free group). There was no difference in the value of Dmin‐PO2 between the asthma‐developed group and the asthma group, or between the asthma‐free group and the age‐matched control group. Among the children with chronic cough, there was no difference in Dmin‐PO2 between girls and boys, either in the asthma‐developed group or in the asthma‐group.

We conclude that 45% of the children with a chronic cough in early life developed asthma, and that BHR in children with chronic cough during the childhood period is a strong risk factor for the development of asthma. Pediatr Pulmonol. 2001; 31:412–418. © 2001 Wiley‐Liss, Inc.
Stat3 activation in prostatic carcinomas
Authors: Dhir Rajiv , Ni Zuyao , Lou Wei , DeMiguel Fernando , Grandis Jennifer Rubin , Gao Allen C.
Published: August 2002

BACKGROUND

Activated Stat3 is found in various types of immortal cell lines and cancers. We and others have previously demonstrated that Stat3 is constitutively activated in rat and human prostate cancer cell lines, and that Stat3 activation is involved in IL‐6‐mediated signaling transduction in prostate cancer cells. The aim of this study is to examine quantitative Stat3 activity in benign and malignant human prostate tissues and analyze the association between Stat3 activity levels and the clinical and pathologic parameters.

METHODS

Stat3 activity levels were analyzed in a total of 104 human primary prostate tissues using electromobility shift assay and immunohistochemical staining for phosphorylated Stat3. The tissue samples used were 42 prostate carcinomas, 42 matched normal prostate tissues from patients with prostatic adenocarcinoma (normal adjacent to tumor), and 20 normal prostate tissues from organ donors.

RESULTS

Significantly higher levels of constitutive Stat3 activity were detected in both prostate carcinomas and the matched normal prostate tissues adjacent to tumors compared to the normal prostates from donors without prostate cancer. There was no significant difference of Stat3 activity in foci of tumor and normal prostate tissue adjacent to tumor. No correlation was seen between Stat3 activity and Gleason grade or serum PSA levels in samples from prostate carcinomas.

CONCLUSIONS

These results indicate that Stat3 is constitutively activated in prostate cancer. The high level of Stat3 activity in both the prostate carcinomas and the normal prostate tissues adjacent to tumors suggests that Stat3 activation may occur before detectable histological alterations of the prostate. Prostate 51: 241–246, 2002. © 2002 Wiley‐Liss, Inc.
Identification of differentially expressed genes associated with androgen‐independent growth of prostate cancer
Authors: Mohler James L. , Morris Tammy L. , Ford O. Harris , Alvey Rudolf F. , Sakamoto Choitsu , Gregory Christopher W.
Published: August 2002

BACKGROUND

The human prostate cancer xenograft, CWR22, similar to most human prostate cancers, regresses after castration and recurs several months after the removal of androgen. Genes uniquely associated with proliferation were identified by comparison of tumors that exist in androgen absence but differ in proliferative capacity.

METHODS

cDNA libraries from CWR22 tumors from 20‐day castrate mice (proliferation undetectable) and recurrent CWR22 tumors (proliferation rate similar to androgen‐dependent CWR22) were compared to evaluate the possibility that proliferation is triggered by either gain of function or loss of suppression. Differentially expressed genes were evaluated further for their temporal association with the onset of cellular proliferation using northern and western analysis and immunohistochemistry of a series of CWR22 tumors that spanned the transition from androgen‐dependent to recurrent growth.

RESULTS

Subtractive hybridization identified 11 candidate genes from among 1,057 clones examined. Northern analysis confirmed differential expression of 8 genes. Western analysis revealed an association between tomoregulin, translation elongation factor‐1α (EF‐1α), Mxi‐1, and thioredoxin‐binding protein 2/vitamin D up‐regulated protein, and the onset of recurrent growth. Immunohistochemistry revealed expression of tomoregulin, EF‐1α, Mxi‐1, and thioredoxin reductase‐1 coincidental with the onset of cellular proliferation on day 120 after castration.

CONCLUSIONS

One or more of these genes may represent an appropriate target to prevent, delay or treat recurrent prostate cancer. Prostate 51: 247–255, 2002. © 2002 Wiley‐Liss, Inc.
Role of Ca2+ for the mechanical properties of fibrillin
Authors: Eriksen Tine A. , Wright David M. , Purslow Peter P. , Duance Victor C.
Published: August 2002

Fibrillin‐rich microfibrils are important structural elements widespread throughout connective tissues. Genetic defects identified in the Ca2+ binding sites of fibrillin have severe effects and in addition Ca2+ has a marked effect on the microfibrillar structure. We have studied the role of Ca2+ on the mechanical behavior of fibrillin‐rich microfibrils using the micro‐needle technique. We find that Ca2+‐depletion results in a 50% decrease in rest length and reduces the stiffness of fibrillin‐rich microfibrils. At high strain, irreversible damage occurs. This behavior is consistent with Ca2+ stabilization of interactions between consecutive EGF‐like domains and breakdown in the quaternary structure upon over‐extension. Proteins 2001;45:90–95. © 2001 Wiley‐Liss, Inc.
Reading the three‐dimensional structure of lattice model‐designed proteins from their amino acid sequence
Authors: Broglia R.A. , Tiana G.
Published: August 2002

While all the information required for the folding of a protein is contained in its amino acid sequence, one has not yet learned how to extract this information to predict the detailed, biological active, three‐dimensional structure of a protein whose sequence is known. Using insight obtained from lattice model simulations of the folding of small proteins (fewer than 100 residues), in particular of the fact that this phenomenon is essentially controlled by conserved contacts (Mirny et al., Proc Natl Acad Sci USA 1995;92:1282) among (few) strongly interacting (“hot”) amino acids (Tiana et al., J Chem Phys 1998;108:757–761), which also stabilize local elementary structures formed early in the folding process and leading to the (postcritical) folding core when they assemble together (Broglia et al., Proc Natl Acad Sci USA 1998;95:12930, Broglia & Tiana, J Chem Phys 2001;114:7267), we have worked out a successful strategy for reading the three‐dimensional structure of lattice model‐designed proteins from the knowledge of only their amino acid sequence and of the contact energies among the amino acids. Proteins 2001;45:421–427. © 2001 Wiley‐Liss, Inc.
Persistence and translocation of a benzothiadiazole derivative in tomato plants in relation to systemic acquired resistance against Pseudomonas syringae pv tomato
Authors: Scarponi Luciano , Buonaurio Roberto , Martinetti Luca
Published: August 2002

A reproducible and accurate procedure, based on HPLC analysis, has been developed to determine simultaneously acibenzolar‐S‐methyl (CGA 245 704) and its acid derivative (CGA 210 007) in tomato leaves. The limit of detection and quantification of the method are 0.015 and 0.15 mg litre−1 for CGA 245 704 and 0.030 and 0.30 mg litre−1 for CGA 210 007. In tomato plants treated with 250 µM CGA 245 704, it was found that the inducer rapidly translocates from treated leaves (cotyledons, 1st and 2nd) to untreated leaves (3rd to 5th), with the maximum translocation (40% of the total quantity found) occurring 8 h after the treatment. CGA 245 704 residues decreased as time elapsed in both treated and untreated tomato leaves, reaching negligible values 72 h after treatment. The acid derivative, CGA 210 007, was formed in tomato plants as early as 2 h after CGA 245 704 treatment, albeit only in the treated leaves. CGA 210 007 residues decreased in treated tomato leaves with a trend similar to that observed for CGA 245 704. Treatment of tomato plants with CGA 245 704 or CGA 210 007 at 250 µM systemically protected the plants against Pseudomonas syringae pv tomato attacks, the causal agent of bacterial speak disease. Evidence of this were reductions in the degree of infection, the bacterial lesion diameter and the bacterial growth in planta. Since neither CGA 245 704 nor CGA 210 007 inhibited bacterial growth in vitro and the protection against bacterial speak of tomato was observed when the two compounds were completely degraded, the protection must be due to the activation of the plant's defence mechanisms.

© 2001 Society of Chemical Industry
Stimulating effects of the insecticide chlorpyrifos on host searching and infestation efficacy of a parasitoid wasp
Authors: Rafalimanana Halitiana , Kaiser Laure , Delpuech Jean‐Marie
Published: August 2002

Hymenopterous parasitoids play an important role in the control of insect populations. During oviposition, Hymenopterous parasitoids use cues such as odours from their environment to locate their specific host. Leptopilina heterotoma (parasitoid of Drosophila larvae) locate their host by probing the substrate with the ovipositor. This behaviour can be induced by the odour of the host substrate alone. We analysed the sub‐lethal effects of chlorpyrifos at LD20 on the probing activity in response to a fruit odour (banana). The insecticide increased the percentage of females spontaneously probing in response to the odour. Parasitoid females were then conditioned to associate banana odour with the oviposition in host larvae. This conditioning enables parasitoids to memorise the odour and to increase their probing response to this odour. During the olfactory conditioning, females exposed to the insecticide found and oviposited in host larvae more quickly than control females. One hour after the olfactory conditioning, females exposed to the insecticide presented a higher increase of their probing response to the odour than controls. Twenty‐four hours after conditioning, the stimulation produced by chlorpyrifos was no longer perceptible, but the level of response of conditioned females was still higher than that of non‐conditioned females, showing that odour memory was not impaired by the insecticide treatment. These sub‐lethal effects, that stimulate host searching by parasitoids without impairing odour memorisation, could increase their parasitic efficiency.

© 2002 Society of Chemical Industry
Towards selective breeding of Atlantic salmon for sea louse resistance: approaches to identify trait markers
Authors: Jones Catherine S , Lockyer Anne E , Verspoor Eric , Secombes Christopher J , Noble Leslie R
Published: August 2002

Several species of sea lice, in particularLepeophtheirus salmonis(Krøyer), affect the welfare and condition of farmed salmon, with an estimated annual cost to the Scottish industry of £15–30 million. In Atlantic salmon, some stocks show resistance toL salmonis. Such natural resistance could be utilized for stock improvement using molecular genetic technologies. The development of molecular markers linked to resistance genes, allowing the identification of resistant fish, could increase the efficacy of selective breeding programmes. Various approaches to achieve this goal are described. One way to identify genes conferring resistance is to develop screens for salmon genes that are activated upon louse infection. One such screen—differential display—requires no previous knowledge of gene sequences, involves no preconceptions about which gene families are involved and can therefore identify novel genes. Preliminary results of comparative gene expression in sea‐louse‐challenged and control fish illustrate the application of differential display.

© 2002 Society of Chemical Industry
A new water‐soluble N‐protecting group, 2‐[phenyl(methyl)sulfonio]ethyloxycarbonyl tetrafluoroborate, and its application to solid phase peptide synthesis in water
Authors: Hojo Keiko , Maeda Mitsuko , Kawasaki Koichi
Published: August 2002

A new water‐soluble N‐protecting group, 2‐[phenyl(methyl)sulfonio]ethyloxycarbonyl tetrafluoroborate, has been prepared and its application to solid phase peptide synthesis in water has been studied. Leu‐enkephalin amide was successfully synthesized in water by the solid phase method using this protecting group. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Ethnobiology of the Nilgiri Hills, India
Authors: Rajan S. , Sethuraman M. , Mukherjee Pulok K.
Published: August 2002

The Nilgiri is a popular massif towering high in the Western Ghats in South India with an altitude of 2623 m. Nature has been magnanimous in bestowing Nilgiri district with rich evergreen temperate to tropical forests. A high degree of biodiversity, marked by varied flora and fauna of good therapeutic potential as well as the varied number of indigenous groups of people in this area, makes it very popular among herbalists. The district has six anthropologically well defined ethnic groups namely Todas, Kotas, Kurumbas, Irulas, Paniyas and Kattunayakas living here possibly since 1200 B.C. The present review highlights the ethnobiological profile of six indigenous populations and their dependence on ambient flora and fauna for traditional health care needs. It has been observed that about 2700 therapeutically potent plant species are available in this hill station of which almost all have come from local medicine. Some have been explored scientifically. However, about 150 plant species are still to be explored for their therapeutic potential. The ethnography, phytochemical and therapeutic uses as well as the anthropological perspectives of the local medicines have been discussed in this review. Copyright © 2002 John Wiley & Sons, Ltd.
Comparative pharmacological study of hydroethanol extracts of Passiflora alata and Passiflora edulis leaves†
Authors: Petry Raquel D. , Reginatto Flávio , de‐Paris Fernanda , Gosmann Grace , Salgueiro Jennifer B. , Quevedo João , Kapczinski Flávio , Ortega George González , Schenkel Eloir Paulo
Published: August 2002

Several species of the genus Passiflora, known in Brazil as ‘maracujá’, have widespread use in folk medicine as sedatives and tranquillizers. The anxiolytic activity of hydroethanol extracts of P. alata and P. edulis leaves was evaluated using the elevated plus‐maze test. The extracts presented anxiolytic activity in dosages around 50, 100 and 150 mg/kg. Copyright © 2001 John Wiley & Sons, Ltd.
Investigations on antimycobacterial activity of some Ethiopian medicinal plants
Authors: Asres K. , Bucar F. , Edelsbrunner S. , Kartnig T. , Höger G. , Thiel W.
Published: August 2002

Fifteen crude extracts prepared from seven Ethiopian medicinal plants used to treat various infectious diseases were assessed for their ability to inhibit the growth of Mycobacterium tuberculosis. A preliminary screening of the crude extracts against M. tuberculosis typus humanus (ATCC 27294) was done by dilution assay using Löwenstein–Jensen medium. None of the tested extracts except the acetone fraction obtained from the stem bark of Combretum molle (R. Br. ex G. Don.) Engl & Diels (Combretaceae) showed significant inhibitory action against this strain. The acetone fraction of the stem bark of C. molle caused complete inhibition at concentrations higher than 1 mg/mL. Phytochemical analysis of the bioactive fraction led to the isolation of a major tannin and two oleanane‐type pentacyclic triterpene glycosides. The tannin was identified as the ellagitannin, punicalagin, whilst the saponins were characterized as arjunglucoside (also called 4‐epi‐sericoside) and sericoside. All the pure compounds were further tested against the ATCC strain. Punicalagin was found to inhibit totally growth of the ATCC and also of a patient strain, which was fully sensitive to the standard antituberculosis drugs, at concentrations higher than 600 µg/mL and 1.2 mg/mL, respectively. On the other hand, the saponins failed to show any action on the ATCC strain. It appears that our findings are the first report of tannins exhibiting antimycobacterial activity. Copyright © 2001 John Wiley & Sons, Ltd.
Chemical constituents and biological activities of Zanthoxylum usambarense
Authors: He Weidong , Puyvelde Luc Van , Kimpe Norbert De , Verbruggen Luc , Anthonissen Kristel , Flaas Mark Van der , Bosselaers Jan , Mathenge Simon G. , Mudida Francis P.
Published: August 2002

Bioassay‐guided fractionation of the dichloromethane extracts of the roots and the bark of Zanthoxylum usambarense led to the isolation of two physiologically active compounds, i.e. canthin‐6‐one 1 (fungicide) and pellitorine 4 (insecticide). Together with oxychelerythrine 2, norchelerythrine 3, (+)‐sesamin 5 and (+)‐piperitol‐3,3‐dimethylallyl ether 6, they were isolated for the first time from this plant. Copyright ­© 2002 John Wiley & Sons, Ltd.
Antioxidants from the bark of Burkea africana, an African medicinal plant
Authors: Mathisen Elin , Diallo Drissa , Andersen Øyvind M. , Malterud Karl Egil
Published: August 2002

The bark of the tree Burkea africana is used medicinally in large areas of sub‐Saharan Africa. The constituents responsible for its putative activity are not well known. We have investigated the bark of B. africana for antioxidant and radical scavenging activity. A hydroethanol bark extract showed high activity, and most of this activity was located in semipolar fractions of the extract. From chromatographic purification and spectroscopical structure studies, we conclude that the active constituents are proanthocyanidins. Two major components appear to be fisetinidol‐(4α‐ → 8)‐catechin 3‐gallate and bis‐fisetinidol‐(4α‐ → 6, 4α‐ → 8)‐catechin 3‐gallate. The latter compound is a new natural product. Smaller amounts of monomeric flavan‐3‐ols (catechin, epicatechin and fisetinidol) were also found. Copyright © 2002 John Wiley & Sons, Ltd.
Numerical and experimental investigation of the deformational behaviour of plastic containers
Authors: Karalekas D. , Rapti D. , Papakaliatakis G. , Tsartolia E.
Published: August 2002

A numerical and experimental study was undertaken to investigate the deformational behaviour of a plastic grooved container used to store agrochemical solutions when loaded under columnar crush conditions. Finite element analysis was implemented to calculate stresses and deformations at various critical points of the container. A non‐linear elastoplastic analysis was performed, based on the ABAQUS FEM computer program. The results of the stress analysis were coupled with a yield criterion to predict the initiation of plastic deformation. The numerically obtained results are compared to those obtained experimentally. It was found that the numerically calculated strains at predetermined locations of the plastic container were in good agreement with the experimentally measured ones. Copyright © 2001 John Wiley & Sons, Ltd.
Analytical gradients for Singer's multicenter n‐electron explicitly correlated Gaussians
Authors: Cafiero Mauricio , Adamowicz Ludwik
Published: August 2002

Analytical gradients for Singer's basis of n‐electron multicenter explicitly correlated Gaussian functions are derived and implemented to variationally optimize the energy and wave function of molecular systems within the Born–Oppenheimer approximation. Wave functions are optimized with respect to (½n(n+1)+3n) nonlinear variational parameters and one linear coefficient per term in the basis set. Preliminary results for the ground states of H3+ and H3 suggest that the method can be more flexible and can achieve lower energies than previously reported calculations. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 82: 151–159, 2001
Comparative studies on the structures, infrared spectrum, and thermodynamic properties of phthalocyanine using ab initio Hartree–Fock and density functional theory methods
Authors: Gong Xue Dong , Xiao He Ming , Tian He
Published: August 2002

The molecular structure, vibrational spectrum, standard thermodynamic functions, and enthalpy of formation of free base phthalocyanine (Pc) have been studied using the density functional theory B3LYP procedure, as well as the ab initio Hartree–Fock method. Various basis sets 3‐21G, 6‐31G*, and LANL2DZ have been employed. The results obtained at various levels are discussed and compared with each other and with the available experimental data. It is shown that calculations performed at the Hartree–Fock level cannot produce a reliable geometry and related properties such as the dipole moment of Pc and similar porphyrin‐based systems. Electron correlation must be included in the calculations. The basis set has comparatively less effect on the calculated results. The results derived at the B3LYP level using the smaller 3‐21G and LANL2DZ basis sets are very close to those produced using the medium 6‐31G* basis set. The geometry of Pc obtained at the B3LYP level has D2h symmetry and the diameter of the central macrocycle is about 4 Å. The enthalpy of formation of Pc in the gas phase has been predicted to be 1518.50 kJ/mol at the B3LYP/6‐311G(2d,2p)//B3LYP/6‐31G* level via an isodesmic reaction. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Molecular dynamics simulations of antimicrobial peptides: From membrane binding to trans‐membrane channels
Authors: Tieleman D. P. , Sansom M. S. P.
Published: August 2002

Using a combination of simulations of alamethicin and other antimicrobial peptides in different environments, we discuss a number of pertinent problems in the biophysics of peptide–lipid interactions and ion channels. Molecular dynamics simulations can be used to obtain detailed information about the structure and dynamics of peptides in membrane environments. Such simulations have yielded interesting information on the dynamics of membrane proteins and of water and ions in ion channels. However, reliably simulating binding to membranes, insertion into membranes, and aggregation of peptides both in and at the surface of membranes remain challenging problems. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 166–179, 2001
A general screened Coulomb potential based implicit solvent model: Calculation of secondary structure of small peptides
Authors: Hassan Sergio A. , Mehler Ernest L.
Published: August 2002

The screened Coulomb potential based implicit solvent model (SCP‐ISM) was recently proposed to describe bulk solvent effects in proteins. In this work it is combined with the Monte Carlo approach of conformational memories (CM) and the PAR22 force field of CHARMM to carry out sequence to structure calculations on peptides that have been shown to adopt α‐helix and β‐hairpin conformations. Simulations at 270 K and 300 K on the peptide, CH3CO‐(AAQAA)3‐NHCH3, result in α‐helix containing populations of 60% and 53% at these two temperatures, respectively. The residue helicities were found to change dramatically between these two temperatures, and at the lower temperature are in good agreement with the experimental helicities estimated at 274 K. CM simulations on the second peptide, CH3CO‐V5DPGV5‐NH2, were carried out to study the β‐hairpin forming propensity of DPro. The calculations gave a population of about 40% β‐hairpin conformations at 300 K with the residues DPro‐Gly forming all or part of the loop. Four main subfamilies of different β‐hairpin/β‐turn structures were found. It was observed that hydrophobic interactions between specific side chains play a fundamental role in the formation and stabilization of the different types of β‐turns. For both peptides, populations of about 40% random coil structures were found. Comparison with available theoretical and experimental results is presented and discussed. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 193–202, 2001
Influence of the alkyl chain length on the excited‐state properties of 4‐dialkyl‐benzonitriles. A theoretical DFT/MRCI study
Authors: Parusel Andreas B. J. , Köhler Gottfried
Published: August 2002

The excited states of various di‐alkyl‐aminobenzonitriles (ABN) emitting dual fluorescence are investigated theoretically by a combination of density functional theory and multireference configuration interaction (DFT/MRCI). Experimentally, it was found that intramolecular charge transfer (ICT) emission increases on expense of the normal fluorescence with increasing n‐alkyl chain length. The long wavelength ICT band becomes the predominant fluorescence band in diisopropylaminobenzonitrile (DIABN) even in an apolar environment. The calculated energy of both the planar and twisted ICT (PICT and TICT) state increases slightly with increasing chain length relative to the energy of the first excited state at optimized planar ground‐state geometry. The good agreement of the calculated TICT state dipole moment with the experimental ICT state dipole moment leads us to the conclusion that the dual fluorescence of all linear substituted di‐alkyl ABNs originate from a TICT state. The bulky system DIABN is twisted by 33° already in the ground state and complete decoupling of donor and acceptor units takes place without a significant energy barrier. In contrast, planarization toward the PICT state is energetically disfavored. Thus, the red‐shifted fluorescence of DIABN is also assigned to emission out of the TICT state. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 149–156, 2001
Structure and reactivity of Nin (n=7–14, 19) clusters
Authors: Böyükata M. , Güvenç Z. B. , Özçelik S. , Durmus P. , Jellinek J.
Published: August 2002

Results of a computer simulation study of Nin (n=7–14, 19) clusters, their structures, energetics, and reactivity with a D2 molecule are presented. The clusters are described by an embedded atom potential, whereas the interaction between the molecule and the clusters is modeled by an LEPS (London–Eyring–Polanyi–Sato) potential energy function. The focus is on structures of the clusters and their reactive channels. The total numbers of stable isomers of the clusters are obtained by sampling their phase space, and the isomers' energy spectra are determined. On the reactive side, dissociative chemisorptions cross sections and decay‐rate constants are calculated. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 208–215, 2001
Quantum chemical analysis of the interactions of transition state analogs with leucine aminopeptidase
Authors: Grembecka J. , Sokalski W. A. , Kafarski P.
Published: August 2002

The physical nature of the intermolecular interactions between several leucine aminopeptidase inhibitors, transition state analogs differing in functional groups, and various constituents of the enzyme active site was analyzed using the hybrid variation–perturbation decomposition of self‐consistent field and second‐order Møller–Plesset perturbation theory interaction energies. The electrostatic term constitutes the dominant contribution in the total interaction energy, although the magnitude of the remaining terms—exchange, delocalization, and correlation—seems to be non‐negligible. The total MP2 interaction energy and its dominant electrostatic term correlate reasonably well with the experimentally measured activities of the inhibitors. The application of this method for activity prediction of leucine aminopeptidase inhibitors resulted in very good agreement between calculated and measured inhibition constant values. Results confirm that the applied approach can be a valuable tool for structure‐based drug design, prediction of binding affinities, determination of protonation state and binding mode in ligand–receptor systems. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 302–310, 2001
Studies in organic mass spectrometry. Part 27. Electron ionisation induced isomerisation of 3‐aryl‐4(3H)‐quinazolinones†
Authors: Ceraulo Leopoldo , Stefano Vita Di , Ferrugia Mirella , Ludányi Krisztina , Segreto Stefania , Vékey Károly
Published: August 2002

The comparison between 70 eV EI (electron ionisation) mass spectra, MIKE (mass analysed ion kinetic energy) and CID (collision induced dissociation) MIKE spectra, KER (kinetic energy release) and KERD (kinetic energy release distribution) data for 2‐methyl‐3‐aryl‐4(3H)‐quinazolinones 1–4, with those of the corresponding 2‐methyl‐4‐aryloxyquinazolines 1′–4′, indicates that aryloxy radical as well as hydrogen or methyl radical losses involve the formation of common intermediates. This suggests the occurrence of migrations of aryl groups from the N‐3 atom to carboxylic oxygen in the molecular ions of 1–4. Copyright © 2001 John Wiley & Sons, Ltd.
Identification of barley and rye varieties using matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry with neural networks
Authors: Bloch Helle Aagaard , Petersen Marianne , Sperotto Maria Maddalena , Keşmir Can , Radzikowski Louise , Jacobsen Susanne , Søndergaard Ib
Published: August 2002

Cereal varieties are normally identified using time‐consuming methods such as visual examination of either the intact grain or one‐dimensional electrophoretic patterns of the grain storage proteins. A fast method for identification of wheat (Triticum aestivum L.) varieties has previously been developed, which combines analysis of alcohol‐soluble wheat proteins (gliadins) using matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry with neural networks. Here we have applied the same method for the identification of both barley (Hordeum vulgare L.) and rye (Secale cereale L.) varieties. For barley, 95% of the mass spectra were correctly classified. This is an encouraging result, since in earlier experiments only a grouping into subsets of varieties was possible. However, the method was not useful in the classification of rye, due to the strong similarity between mass spectra of different varieties. Copyright © 2001 John Wiley & Sons, Ltd.
Analysis of saccharides in beer samples by flow injection with electrospray mass spectrometry
Authors: Mauri Pierluigi , Minoggio Markus , Simonetti Paolo , Gardana Claudio , Pietta Piergiorgio
Published: August 2002

Saccharides in foods play important roles, as they are essential substrates for fermentation processes. In brewing, the concentration of maltooligosaccharides influences the characteristics of beers and therefore their determination is of great practical interest. Electrospray ionization mass spectrometry (ESI‐MS) was applied to identify and characterise maltooligosaccharides in beer samples. The effects due to different cation concentrations and dilution of samples were studied. Furthermore, quantitative analyses of maltooligosaccharides by means of flow‐injection ESI‐MS (FI/ESI‐MS) of 1‐µL beer samples (diluted 1000‐fold) are described. Copyright © 2002 John Wiley & Sons, Ltd.