bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating contemporary and historical sediment inputs to Slapton Higher Ley: an analysis of the robustness of source ascription methods when applied to lake sediment data
Authors: Jenns N. , Heppell C. M. , Burt T. P. , Walden J. , Foster I. D. L.
Published: December 2002

This paper reports the results of a quantitative source analysis of the contemporary and historical sediments delivered to Slapton Higher Ley (Devon, UK). Contemporary suspended and bedload sediment inputs to the Higher Ley were apportioned successfully using R‐ and Q‐mode analysis and an unmixing model. Pasture topsoil was responsible for 80% of the suspended sediment load during stormflow, but only 50% under baseflow conditions. Channel bank material dominated bedload (70–80%).

Dating by 137Cs of three cores from the Higher Ley indicates that rapid sedimentation has occurred since the 1950s and that pasture topsoil has been the dominant source of sediment deposited in the Higher Ley since the early 1980s. Both the unmixing model and R‐ and Q‐mode analysis support this interpretation. However, the robustness and validity of applying such source ascription techniques to the sediment cores of the Higher Ley is debatable, as chemical and mineral magnetic signatures in the cores are ‘diluted’ in comparison with sediment sources from the Slapton catchment. Particles‐size effects, selective transport and post‐depositional physical and chemical processes are examined as possible causes of this dilution effect. Post‐depositional alteration of the sediment was identified as the most probable explanation, but further analysis of the process was not possible within the scope of this study. Copyright © 2002 John Wiley & Sons, Ltd.
Release of dissolved organic carbon from upland peat
Authors: Worrall F. , Burt T. P. , Jaeban R. Y. , Warburton J. , Shedden R.
Published: December 2002

This study examines the release of dissolved organic carbon (DOC) from upland peat during the period of the autumn flushing. Hydroclimatic conditions were monitored in conjunction with measurements of absorbance and the E4/E6 ratio of the stream draining an 11·4 km2 upland peat catchment in northern England. During two months of monitoring the effects of 67 separate rainfall events were examined showing that:

The peat behaves hydrologically as if it were a two end‐member system consisting of old, interevent, and new, event, water. Runoff is initiated by percolation excess of new water at the acrotelm–catotelm interface.

The discharge of dissolved organic matter behaves like a three end‐member system with the between‐event water being low in DOC and storm events being characterized by two types of water. Initial runoff being characterized by new water rich in DOC that gives way to new water depleted in DOC. This transition can be ascribed to the runoff progressing from throughflow within the acrotelm progressing to saturation‐excess overland flow.

Depletion of DOC during storm events is accompanied by a change in the character of the DOC as the E4/E6 ratio changes. This suggests that the decrease in DOC during events is the result of exhaustion of reserves rather than changes in the flowpaths being utilized by runoff.

The amount of carbon released in any event is critically dependent upon the time between events during which oxidation processes generate a reservoir of available carbon. Production of available carbon in the catchment is as high as 4·5 g C per day per m3 of peat, suggesting a turnover rate of peat of the order of 42 years. Copyright © 2002 John Wiley & Sons, Ltd.
Smoke exposure, histologic type and geography‐related differences in the methylation profiles of non‐small cell lung cancer
Authors: Toyooka Shinichi , Maruyama Riichiroh , Toyooka Kiyomi O. , McLerran Dale , Feng Ziding , Fukuyama Yasuro , Virmani Arvind K. , Zochbauer‐Muller Sabine , Tsukuda Kazunori , Sugio Kenji , Shimizu Nobuyoshi , Shimizu Kenji , Lee Huei , Chen Chih‐Yi , Fong Kwun M. , Gilcrease Michael , Roth Jack A. , Minna John D. , Gazdar Adi F.
Published: December 2002

Aberrant methylation of several known or putative tumor suppressor genes occurs frequently during the pathogenesis of lung cancers. There are major smoke exposure, histology, geography and gender‐related changes in non‐small cell lung cancer (NSCLC). We investigated smoking‐related, histologic, geographic and gender differences in the methylation profiles of resected NSCLCs. We examined 514 cases of NSCLC and 84 corresponding nonmalignant lung tissues from 4 countries (USA, Australia, Japan and Taiwan) for the methylation status of 7 genes known to be frequently methylated in lung cancers [p16, RASSF1A (RAS association domain family 1), APC, RARβ, CDH13, MGMT and GSTP1]. Multivariate analyses were used for data analysis. Adenocarcinoma was the major histologic type in women and never smokers; analyses that involved smoke exposure and gender were limited to this histology. Our major findings are a) methylation status of any single gene was largely independent of methylation status of other genes; b) the rates of methylation of p16 and APC and the mean Methylation Index (MI), a reflection of the overall methylation status, were significantly higher in ever smokers than in never smokers; c) the mean MI of tumors arising in former smokers was significantly lower than the mean of current smokers; d) the methylation rates of APC, CDH13 and RARβ were significantly higher in adenocarcinomas than in squamous cell carcinomas; e) methylation rates of MGMT and GSTP1 were significantly higher in the USA and Australian cases than in those from Japan and Taiwan; and (f) no significant gender‐related differences in methylation patterns were noted. Our findings demonstrate important smoke exposure, histologic type and geography‐related differences in the methylation profiles of NSCLC tumors. © 2002 Wiley‐Liss, Inc.
Reg IV, a new member of the regenerating gene family, is overexpressed in colorectal carcinomas
Authors: Violette Sabine , Festor Estelle , Pandrea‐Vasile Ivona , Mitchell Valérie , Adida Colette , Dussaulx Elisabeth , Lacorte Jean‐Marc , Chambaz Jean , Lacasa Michel , Lesuffleur Thécla
Published: December 2002

A better understanding of the mechanisms by which colon tumor cells are able to survive exposure to drugs would be valuable for the development of new therapeutic strategies. We used differential display‐PCR to compare gene expression in the drug‐sensitive HT‐29 colon cancer cell line and 3 drug‐resistant subpopulations derived from this parental cell line. One of the genes identified is a new gene, Regenerating IV gene (Reg IV), and was strongly overexpressed in HT‐29 drug‐resistant cells. Other drug‐resistant cell lines expressed Reg IV at a high level, whereas a low expression was noted in sensitive cell lines. Northern blot and real‐time PCR analysis showed that Reg IV is more strongly expressed in 71% of colorectal tumors (in particular in mucinous carcinomas) than in normal colon tissues. The comparison of Reg IV expression with that of other REG genes, Regenerating Iα or (Reg Iα), Regenerating Iβ (Reg Iβ) and Pancreatitis‐associated protein (PAP), highlights its predominant expression in colorectal tumors. Reg IV mRNA‐positive tumor cells display different phenotypes: mucus‐secreting, enterocyte‐like or undifferentiated. Interestingly, whereas Reg IV expression is low in normal colon, its level in normal small intestine is similar to that in some colorectal tumors. In normal tissue, Reg IV mRNA‐positive cells are mostly enteroendocrine cells and goblet cells. Our results point out the potential role of Reg IV in colorectal tumors and its subsequent interest as a pronostic indicator of tumor survival. © 2002 Wiley‐Liss, Inc.
Synergistic antineoplastic action of DNA methylation inhibitor 5‐AZA‐2′‐deoxycytidine and histone deacetylase inhibitor depsipeptide on human breast carcinoma cells
Authors: Primeau Mélanie , Gagnon Jacynthe , Momparler Richard L.
Published: December 2002

During tumorigenesis, cancer‐related genes can be silenced by aberrant DNA methylation and by changes in chromatin structure. It has been reported that 5‐aza‐2′‐deoxycytidine, a potent inhibitor of DNA methylation, in combination with histone deacetylase inhibitors, can produce a synergistic reactivation of these genes. The aim of our study was to investigate the in vitro antineoplastic activity of 5‐aza‐2′‐deoxycytidine in combination with depsipeptide, a potent histone deacetylase inhibitor, against MDA‐MB‐231 and MDA‐MB‐435 human breast carcinoma cell lines. We observed that the combination of 5‐aza‐2′‐deoxycytidine and depsipeptide produced a synergistic antineoplastic effect against these tumor cells as compared to either agent administered alone. We also investigated the effect of this drug combination on the activation of maspin and gelsolin expression. These 2 genes whose function is to suppress tumor metastasis have been reported to be silenced by epigenetic events in breast cancer. Using semi‐quantitative RT‐PCR, we observed that 5‐aza‐2′‐deoxycytidine in combination with depsipeptide produced a greater reactivation of both maspin and gelsolin as compared to each agent alone. The synergistic interaction between 5‐aza‐2′‐deoxycytidine and depsipeptide on breast carcinoma cell lines provides a rationale to investigate this interesting drug combination in future clinical trials on patients with advanced breast cancer. © 2002 Wiley‐Liss, Inc.
Suppression of lung metastasis of mouse Lewis lung cancer P29 with transfection of the ganglioside GM2/GD2 synthase gene
Authors: Chen Ho‐Hsiang , Fukumoto Satoshi , Furukawa Keiko , Nakao Akimasa , Akiyama Seiji , Urano Takeshi , Furukawa Koichi
Published: December 2002

Ganglioside functions in tumor metastasis were analyzed by carbohydrate remodeling of a mouse Lewis lung cancer (subline P29) by introducing β1,4GalNAc‐T cDNA. Although P29 was originally a low‐metastatic subline in the s.c. injection system, it showed high potential in lung metastasis when i.v.‐injected via the tail vein. Two lines of GM2+ transfectants showed markedly reduced metastatic potential to the lung compared to 2 control lines. However, cell proliferation rates and expression levels of various cell adhesion molecules, e.g., integrin family members, SLex and CD44, were essentially unchanged after transfection of the cDNA. Then, cell adhesion to fibronectin‐coated dishes was examined, showing that GM2+ transfectants attached to the plates much more slowly than controls, suggesting functional modulation of integrins with newly expressed GM2. Phosphorylation of the FAK located at downstream of integrin molecules was markedly reduced in GM2+ transfectants, suggesting that GM2 suppressed cell adhesion signals via fibronectin–integrin interaction. © 2002 Wiley‐Liss, Inc.
A prospective study of adiposity and postmenopausal breast cancer risk: The Malmö diet and cancer study
Authors: Lahmann Petra H. , Lissner Lauren , Gullberg Bo , Olsson Håkan , Berglund Göran
Published: December 2002

High BMI is a well‐known risk factor for postmenopausal breast cancer. There have been some reports of excess risk in association with weight gain and WHR, but little is known about the influence of body fatness per se. Using data from the Malmö Diet and Cancer Study, a prospective cohort study, 12,159 postmenopausal women (59.9 ± 7.7 years) were categorized by quintiles of baseline anthropometric and impedance measures and reported weight change since age 20. RRs from multivariate Cox regression models were calculated. All analyses were adjusted for age, height, smoking, alcohol consumption, occupation, marital status, parity, age at first pregnancy, age at menarche and current hormone use. During the 5.7 years of follow‐up, there were 246 incident breast cancer cases. Weight, height, BMI and %BF were positively associated with risk of breast cancer (ptrend ≤ 0.02). %BF showed the strongest association, with an RR of 2.01 (95% CI 1.26–3.21) in the highest vs. lowest quintile. There was significant modification of this association by hormone use, suggesting a greater impact of body fatness among nonusers. Fat distribution was not independently associated with breast cancer risk. Women with weight gain >21 kg (top quintile) had an RR of 1.75 (95% CI 1.11–2.77) compared to women with low weight gain. Breast cancer risk in postmenopausal women is predicted by increased body fat and weight gain. %BF is a more discriminating risk factor for breast cancer incidence than the commonly used BMI. © 2002 Wiley‐Liss, Inc.
Effect of treatment sequence with radiotherapy and the antiestrogen EM 800 on the growth of ZR 75 1 human mammary carcinoma in nude mice
Authors: Gutman Mathieu , Couillard Steeve , Labrie Fernand , Candas Bernard , Labrie Claude
Published: December 2002

We demonstrated previously that continuous administration of EM‐800, a SERM having pure antiestrogenic activity in the mammary gland and endometrium in combination with monthly radiotherapy caused a greater inhibition of human ZR 75 1 tumor growth in nude mice than either therapy used alone. To further optimize therapy, we have now examined the effect of various treatment sequences to determine the optimal treatment regimen in the same model. EM 800 was given at the maximally effective oral dose of 300 μg daily. External beam radiation therapy (RTX) was carried out (2 Gy/tumor/day, 5 days per week for 3 weeks) for a total of 30 Gy/tumor delivered directly to the tumor while shielding the rest of the animal body. There was no evidence of RTX‐related morbidity. Continuous treatment with EM 800 was initiated either 3 weeks before or at the same time as RTX, immediately after RTX, or 3 weeks before and immediately after RTX. After 156 days of treatment, EM 800 alone caused a 75% decrease in average tumor area, an effect equivalent to that achieved by ovariectomy. RTX alone, on the other hand, caused a transient 30% decrease in tumor area regardless of treatment sequence, whereas combined treatment with EM 800 and RTX was superior to either treatment alone. Combined treatment with EM 800 and RTX both started on Day 1 caused the greatest (88%), most rapid (50% in 2 weeks) and sustained decrease in tumor size. The present data indicate that optimal reduction in breast tumor size is achieved by continuous administration of EM 800 and RTX started simultaneously on Day 1. © 2002 Wiley‐Liss, Inc.
The sero‐epidemiology of Kaposi's sarcoma‐associated herpesvirus (KSHV/HHV‐8) in adults with cancer in Uganda
Authors: Newton Robert , Ziegler John , Bourboulia Dimitra , Casabonne Delphine , Beral Valerie , Mbidde Edward , Carpenter Lucy , Reeves Gillian , Parkin D. Maxwell , Wabinga Henry , Mbulaiteye Sam , Jaffe Harold ,   the Uganda Kaposi's Sarcoma Study Group, Weiss Robin , Boshoff Chris
Published: December 2002

The association between the prevalence of antibodies against Kaposi's sarcoma‐associated herpesvirus (KSHV or human herpesvirus 8 [HHV‐8]) and sociodemographic, sexual, reproductive and lifestyle factors was investigated in a study of adults presenting with cancer at hospitals in Kampala, Uganda. Patients were interviewed and tested for antibodies against KSHV (using an indirect immunofluorescent assay). Data are presented for 607 patients who were not infected with the human immunodeficiency virus‐1 (HIV) and who did not have Kaposi's sarcoma (these included people with cancers of the uterine cervix [140], breast [58], liver [41], oesophagus [36], lymphoma [47], other cancers [285] and benign tumours [63]). The prevalence of anti‐KSHV antibodies was 50% overall (302/607) and did not differ significantly by cancer site (p = 0.4) or sex (p = 0.2), but increased linearly with age from 35% in those under 25 years to 55% in those 45 years and over (χ2 trend [1 df] = 9.1; p < 0.001). After adjusting for age and sex, anti‐KSHV antibodies were more common in tribal groups other than the Baganda tribe (54% vs. 45% among Baganda; p = 0.02), but there was no significant (p > 0.05) variation in seroprevalence by district of birth, region of residence prior to becoming ill or various measures of wealth. The prevalence of anti‐KSHV antibodies decreased with increasing number of older siblings, although this may be due to chance (p = 0.05) and was higher among people who had ever been married (p = 0.03). There was no significant association (p > 0.05) between the presence of antibodies against KSHV and other sexual and reproductive factors. Among the 302 patients with anti‐KSHV antibodies, the proportion with high titres increased linearly with increasing age (p = 0.03) and was higher among those reporting having had a blood transfusion (p = 0.03). In conclusion, in this population in Uganda, where KSHV is relatively common, the prevalence of anti‐KSHV antibodies increased with age but showed little association with nearly 50 other factors studied. © 2002 Wiley‐Liss, Inc.
A cluster analysis of symptom patterns and adjustment in Vietnam combat veterans with chronic posttraumatic stress disorder
Authors: Mazzeo Suzanne E. , Beckham Jean C. , Witvliet Charlotte vanOyen , Feldman Michelle E. , Shivy Victoria A.
Published: December 2002

This study investigated whether a subgroup of veterans with malignant posttraumatic stress syndrome, as described by Rosenheck (1985) and Lambert et al. (1996), could be identified via cluster analysis within two samples of Vietnam veterans with combat‐related posttraumatic stress disorder (PTSD). In the initial subsample (n = 157), four clusters were identified, including a subgroup that scored consistently higher on measures
of interpersonal violence and current physical problems. Similar results were found in the cross‐validation subsample (n = 156). These results provide support for the theoretical concept of malignant PTSD and suggest that veterans with chronic PTSD are not homogenous. Whereas some manifest extreme levels of both functional impairment and PTSD symptomatology, others exhibit markedly less functional impairment despite manifesting clinically significant levels of PTSD. Clinicians can consider this heterogeneity in their treatment decisions. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 1555–1571, 2002.
Efficacy of eye movement desensitization and reprocessing in the treatment of specific phobias: Four single‐case studies on dental phobia
Authors: De Jongh A. , van den Oord H.J.M. , ten Broeke E.
Published: December 2002

A series of single‐case experiments was used to evaluate the application of Eye Movement Desensitization and Reprocessing (EMDR) to traumatically induced dental phobia. Following two to three sessions of EMDR treatment, three of the four patients demonstrated substantially reduced self‐reported and observer‐rated anxiety, reduced credibility of dysfunctional beliefs concerning dental treatment, and significant behavior changes. These gains were maintained at six weeks follow‐up. In all four cases, the clinical diagnosis present at pretreatment was not present at posttreatment at a clinical level. All patients actually underwent the dental treatment they feared most within three weeks following EMDR treatment. The findings support the notion that EMDR can be an effective treatment alternative for phobic conditions with a trauma‐related etiology. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 1489–1503, 2002.
Bioflavours and fragrances via fermentation and biocatalysis
Authors: Vandamme Erick J , Soetaert Wim
Published: December 2002

A condensed overview is given of the potential offered by bacteria, fungi and yeasts to produce a wide range of bioflavours and fragrances. A few commercialised processes are also discussed. The advantages of microbial processes versus chemical synthesis or extraction are outlined. Both de novo fermentation processes as well as bioconversions based on adding specific precursors/intermediates to microbial cells or enzymes are illustrated via typical examples. Bottlenecks, which currently hinder a wider introduction of this flavour biotechnology, are indicated and some solutions are proposed.

© 2002 Society of Chemical Industry
Removal of trivalent chromium(III) from solution by biosorption in cork powder
Authors: Machado Remígio , Carvalho Jorge R , Joana Neiva Correia M
Published: December 2002

The removal of trivalent chromium from solutions using biosorption in cork powder is described. The adsorption isotherm was determined, along with the effect of different variables, such as biomass particle size, solid–liquid ratio, reaction time, metal concentration and pH, on the efficiency of chromium removal. It was concluded that the adsorption is slow and favoured by an increase in pH. Therefore, using a solid–liquid ratio of 4 g dm−3 it is possible to reduce the chromium concentration in the solution from 10 mg dm−3 to less than 1.5 mg dm−3 in 2 h at 22 °C. The kinetic studies verified that the sorption of chromium by cork was described by a second‐order model. The elution results showed that 50% of the chromium bound to the cork was eluted using 0.5 mol dm−3 H2SO4 and that cork maintains its binding capacity over four cycles of biosorption/elution.

© 2002 Society of Chemical Industry
Delegation and strategic incentives for managers in contests
Authors: Kräkel Matthias
Published: December 2002

Owners usually want their managers to maximize profits. As the literature on strategic delegation has shown it may be beneficial to owners to put a positive weight on sales in the optimal linear incentive scheme for managers to make them behave more aggressively in the market. This paper shows that if the competition between the managers can be characterized as a contest, owners may induce their managers to maximize sales. Moreover, there is a first‐mover advantage for owners when choosing their incentive schemes. If delegation is endogenous the type of contest will determine whether all owners delegate their decisions to managers or not. Copyright © 2002 John Wiley & Sons, Ltd.
Macroeconomic news and the returns of financial companies
Authors: Ewing Bradley T.
Published: December 2002

This research is concerned with the response of the NASDAQ Financial 100 index to macroeconomic news. The paper employs the newly developed technique of generalized impulse response analysis to examine how macroeconomic shocks affect the performance of the financial sector. The results identify the magnitude and persistence of the response of financial companies stock returns arising from shocks to the stance of monetary policy, real output, inflation, and risk. The findings add to the literature on the determinants of financial sector stocks and on the relationship between the stock market and the macroeconomy. Copyright © 2002 John Wiley & Sons, Ltd.
1H chemical shifts in NMR: Part 19. Carbonyl anisotropies and steric effects in aromatic aldehydes and ketones
Authors: Abraham Raymond J. , Mobli Mehdi , Smith Richard J.
Published: December 2002

The 1H chemical shifts of benzaldehyde, 2‐chloro‐, 2‐hydroxy‐ and 2‐methoxybenzaldehyde, acetophenone, 2‐methoxy‐ and 2‐hydroxyacetophenone, indanone, anthraquinone, fluorenone, anthrone, α‐tetralone, 2,4,6‐trimethylacetophenone, 9‐acetylanthracene, 9‐anthranaldehyde and benzosuberone were obtained and completely assigned in CDCl3 and DMSO solution. In anthrone a keto–enol tautomerism (anthrone–9‐hydroxyanthracene) was observed by NMR in hydrogen bonding solvents but not chloroform. The percentage of enol is linearly dependent on the Kamlett β hydrogen bonding parameter of the solvent, and not the solvent relative permittivity. The chemical shift data allowed the determination of the carbonyl substituent chemical shifts (SCS) in these molecules. These were analysed in terms of the carbonyl electric field, magnetic anisotropy and steric effects for long‐range protons together with a model (CHARGE7) for the calculation of the two‐ and three‐bond effects. The SCS of the carbonyl bond was reproduced with an asymmetric magnetic anisotropy acting at the midpoint of the carbonyl bond with values of Δχpar and Δχperp of 6.36 and −11.88 (10−30 cm3 molecule−1) plus a steric term from the oxygen atom and the CO electric field effect. The short‐range effects of the carbonyl group on the aldehyde proton were modelled using the appropriate β functions in the CHARGE routine. For the 9‐substituted anthracenes the Hückel π calculation was modified to account for the 1H chemical shifts of the H‐10 protons. This model gave a comprehensive calculation of the 1H chemical shifts of these aromatic aldehydes and ketones. For the data set of 129 chemical shifts ranging from δ 2.5 to 11.5 the r.m.s. error of the observed vs calculated shifts was 0.094 ppm. The CO anisotropy and oxygen shielding differ appreciably from the corresponding values for the aliphatic aldehydes and ketones but are similar to the values for the CO group of amides, illustrating the effect of conjugation on these parameters. The model was used in the conformational analysis of some related compounds. In 2‐chlorobenzaldehyde the chemical shift calculations support a non‐planar molecule with the aldehyde–ring dihedral angle in the trans conformer of ca 25°. In the strained seven‐membered ring of benzosuberone, the model was used to test calculated geometries. The ab initio geometry at the B3LYP(6–31++G(d,p)) level gave the best agreement with the observed shifts. Copyright © 2002 John Wiley & Sons, Ltd.
Increasing spectral information with shorter acquisitions: the advantages of using F1 selection in structural determinations
Authors: Yang Shengtian , Gard Janice K. , Harrigan George , Parnas Barry , Likos John , Crouch Ron
Published: December 2002

The structural elucidation of complex materials by NMR is complicated by the common occurrence of nearly coincident resonances. Congested regions necessitate increased spectral resolution, with additional time increments needed for 2D NMR spectroscopy, resulting in longer acquisition times. These demands conflict with the ever‐increasing demands for instrument time and with long‐term sample stability. Selective spectroscopy addresses both of these problems. By focusing attention only on the region of interest, fewer increments are needed. Shorter acquisitions are obtained, with a higher information content. Alternatively, the spectroscopist may choose to use these time savings to collect additional transients, allowing the study of smaller amounts of material, or low‐level impurities/isomers. Using a carbohydrate as our example, we illustrate the utility of this methodology using selHMQC, selHMBC (IMPRESS) and selHMQCTOCSY. We have found this methodology useful in the coupling of efficiency and productivity of NMR spectroscopy. Copyright © 2002 John Wiley & Sons, Ltd.
Lanthanide‐induced shifts in the structural elucidation of β‐hydroxydecalones
Authors: Schenato Rossana A. , dos Santos Éverton M. , Gonçalves Paulo F. B. , Tenius Beatriz S. M. , de Oliveira Eduardo R. , Caracelli Ignez , Zukerman‐Schpector Julio
Published: December 2002

The use of Eu(fod)3 in the analysis of the 1H and 13C NMR spectra of cis and trans‐fused β‐hydroxydecalones is described. The relative configuration of the substituents is discussed using the PMLIS algorithm to determine the lanthanide (Eu) ion position in the complex in an effective axially symmetric model. The conformations of two cis‐decalones are also discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Macropremies: Underprivileged newborns
Authors: Amiel‐Tison Claudine , Allen Marilee C. , Lebrun Francoise , Rogowski Jeannette
Published: December 2002

The focus of neonatal intensive care has been on very low birthweight infants, who comprise only 1.4% of neonates. Too little attention is paid to moderately preterm infants that we call macropremies or moderately low birthweight infants (MLBW, with birthweights 1500–2500 grams). Admitting over half MLBW infants to normal nurseries presumes that they have few needs and an excellent prognosis similar to fullterm newborns. It does not take into account the macropremie's vulnerability to complications of prematurity due to immature organ systems. Obstetricians are increasingly willing to deliver these infants prematurely for signs of fetal distress. As many as 25% of children with cerebral palsy referred to a disability clinic in Paris were MLBW, with hypoxic‐ischemic‐inflammatory associated disorders in one‐third. The majority of MLBW infants who required neonatal intensive care at a tertiary care center in Baltimore had complications of prematurity: 47% had respiratory problems, 20% had feeding intolerance and 9% had hypoglycemia. MLBW infants comprise 5–7% of the neonatal population but account for 14% of neonatal deaths, 18–37% of children with cerebral palsy and 7–12% of children with mental retardation. Increasing the level of neonatal care for the macropremie's transition to extrauterine life would be economically feasible if it prevented as few as 30% of cases of major disability. A change in attitude towards this low risk (but not risk free) group of MLBW infants will both reduce morbidity and improve their health and neurodevelopmental outcome. It includes: 1) Providing an intermediate level of neonatal care for a short duration, with close monitoring and prompt intervention as needed, and 2) Neonatal neurodevelopmental screening to allow focused neurodevelopmental followup of MLBW infants with abnormalities. MRDD Research Reviews 2002;8:281–292. © 2002 Wiley‐Liss, Inc.
Preterm outcomes research: A critical component of neonatal intensive care
Authors: Allen Marilee C.
Published: December 2002

While early preterm outcome studies described the lives of preterm survivors to justify the efforts required to save them, subsequent studies demonstrated their increased incidence of cerebral palsy, mental retardation, sensory impairments, minor neuromotor dysfunction, language delays, visual‐perceptual disorders, learning disability and behavior problems compared to fullterm controls. Because infants born at the lower limit of viability require the most resources and have the highest incidence of neurodevelopmental disability, there is concern that resources have gone primarily to neonatal intensive care and are not available for meeting the followup, health, educational and emotional needs of these fragile infants and their families. Despite many methodological concerns, preterm outcome studies have provided insight into risk factors for and causes of CNS injury in preterm infants. Nevertheless, it remains difficult to predict neurodevelopmental outcome for individual preterm infants. Perinatal and neonatal risk factors are inadequate proxies for neurodevelopmental disability. Recent randomized controlled trials with one to five year neurodevelopmental followup have provided valuable information about perinatal and neonatal treatments. Recognizing adverse longterm neurodevelopmental effects of pharmacological doses of postnatal steroids is a sobering reminder of the need for longterm neurodevelopmental followup in all neonatal randomized controlled trials. Ongoing longterm preterm neurodevelopmental studies, analysis of changes in outcomes over time and among centers, and evaluation of the longterm safety, efficacy and effectiveness of many perinatal and neonatal management strategies and proposed neuroprotective agents are all necessary for further medical and technological advances in neonatal intensive care. MRDD Research Reviews 2002;8:221–233. © 2002 Wiley‐Liss, Inc.
Ophthalmological problems of the premature infant
Authors: Repka Michael X.
Published: December 2002

Preterm infants are more likely than term infants to have significant abnormalities of all parts of the visual system leading to reduced vision. The most common problem is retinopathy of prematurity (ROP). The frequency and severity of this disorder is inversely related to gestational age. Damage ranges from minor to catastrophic. Preterm infants also have higher rates of amblyopia, strabismus, refractive error, and cortical visual impairment. The later problem is largely associated with neonatal brain injury. Years later, these children may develop glaucoma and retinal detachments. MRDD Research Reviews 2002;8:249–257. © 2002 Wiley‐Liss, Inc.
Electrical properties of polymers: space‐charge behaviour in insulating polymers under high‐voltage direct current
Authors: Mizutani Teruyoshi
Published: December 2002

The space‐charge distributions in various low‐density polyethylenes (LDPEs) under a high DC voltage were measured. They strongly depended upon the physical structure of the LDPE, additives, electrode materials, applied field and temperature. Both positive and negative carriers were injected more easily from the semiconductive (SC) electrode than the Al or Au electrode and, as a result, a larger amount of space‐charge was accumulated for the SC electrode. Space‐charge dynamics depended upon the density of LDPE. Injected space‐charge moves more easily toward the counterelectrode in LDPE with a lower density and it decays more quickly after short‐circuiting. Additives, such as antioxidants and by‐products of crosslinking and oxidation of LDPE, strongly affected the space‐charge distribution in LDPE. These results give a good guide for the development of high‐voltage DC (HVDC) extruded polyethylene cables.

© 2002 Society of Chemical Industry
Space‐charge measurement in polymer films by the new alternating thermal wave method
Authors: Reboul Jean‐Michel , Carin Régis
Published: December 2002

Space‐charge prospecting is commonly used as a way of evaluating the electrical qualities and reliability of insulating polymers. However, the various methods for space‐charge measurement are not adapted to thin films. The present work is concerned with the development of a new method suitable for thin polymer films intended for the manufacture of capacitors. The principle is the processing of the current response of a film sample submitted to alternating thermal stimulations. A controlled thermo‐electric module is used to generate the thermal stimulations. The current response is processed as arising from an equivalent pattern of discrete charged planes, parallel to the film faces. Some results obtained with this model on 100 µm thick polypropylene films submitted to various treatments are given.

© 2002 Society of Chemical Industry
Water absorption in epoxy resins by electronic energy transfer
Authors: Martin O , Pastoriza A , Mikes F , Baselga J
Published: December 2002

Water absorption of an epoxy resin was studied by steady‐state fluorescence spectroscopy and gravimetry. It was found that the intrinsic emission of the epoxy resin could be modified selecting an adequate excitation wavelength. The epoxy component of the resin was labelled with a trans‐4‐nitro‐4′‐aminostilbene fluorescent probe. Using an excitation wavelength of 340 nm it was possible to induce energy transfer to the suitable acceptor trans‐4‐nitro‐4′‐dialkylaminostilbene (NDAS). The relative fluorescence intensity I433/I596 was used as a convenient means to follow the quenching effect of water on the emission of NDAS when excited via energy transfer. It was found that both the relative intensity and the water content increase linearly with the square root of diffusion time in the early stages of the process. The apparent Stern–Volmer constants for the quenching of the fluorophore, when excited directly in a fluid THF solution or in the polymer matrix, were very similar but lower than when the fluorophore was excited via energy transfer. It was concluded that, at least in the early stages of the water diffusion process, the interchromophoric distance should increase.

© 2002 Society of Chemical Industry
Poly(ethylene oxide) containing segmented networks as precursors for ion‐conducting solid‐state materials
Authors: Cosaert Kathelijne , Eeckhout Els , Goethals Eric , Prez Filip Du , Guégan Philippe , Cheradame Hervé
Published: December 2002

Segmented networks containing high contents of poly(ethylene oxide) (PEO) have been investigated as a new type of polymer architecture in the field of solid ion‐conducting materials. Such networks have been synthesized by the radical copolymerization of α,ω‐bis‐methacrylate‐terminated PEO with several types of methacrylates. DMA analysis showed that the phase behaviour of the segmented networks is determined by the fraction and molecular weight of the PEO chains and by the nature of the second component. It has been demonstrated by DSC that, under certain conditions, a small fraction of polymethacrylate is sufficient to prevent the PEO chains from crystallization. Complex impedance measurements of the networks with different concentrations of lithium salt over a wide range of temperatures demonstrated the influence of the nature of the polymethacrylate on the performance of the solid polymer electrolytes. Ionic conductivities at room temperature up to 6 × 10−5 S cm−1 could be achieved for segmented networks containing a minor fraction of poly(n‐butyl methacrylate).

© 2002 Society of Chemical Industry
Pendant drop formation on a cylindrical polymeric fibre network: predicting the drop shape and its evolution beyond the traditional Laplace surface tension equation
Authors: Rebouillat Serge , Steffenino Benoit , Salvador Bruno
Published: December 2002

Wettability of fibres is generally characterised by the contact angle of axisymmetrical drops on single fibres. The use of the inflexion angle was introduced as a more precise parameter useful for characterising fibre–liquid interactions. This method does not cover the case of non‐symmetrical drops that are usually formed on hydrophobic monofilaments. Therefore in order to study all multifilament fibre surfaces, the inflexion angle is combined to the pendant drop description of Bashforth and Adams. The Microwetting® device is used for this purpose and, more specifically, to measure the shape evolution of pendant drops hanging under planar surfaces and fibre networks. Several methods are proposed to calculate the characteristic drop shape factor, Bo, as a function of the inflexion angle. The latter relationship is instrumental in obtaining a complete abacus to classify fibre surfaces. The volume to surface relationship gives rough estimations of Bo, whereas a force balance on a drop volume provide a much more accurate series of data. Experiments were conducted with para‐aramid Kevlar® fibres and with a glass plane; related statistics are presented. Other surfaces and fibre networks serve to validate the approach. A derived wettability ranking is discussed.

© 2002 Society of Chemical Industry
Experimental aspects of polymer dynamics
Authors: Richter Dieter , Monkenbusch Michael , Willner Lutz , Wischnewski Andreas , Arbe Arantxa , Colmenero Juan
Published: December 2002

Neutron scattering accesses the space time evolution of molecular motion on atomistic length and time scales covering all dynamical processes from local relaxations to overall chain diffusion. Using the dynamics of a chain in the melt as an example, we review results obtained by the various high resolution neutron scattering techniques and outline future opportunities.

Copyright © 2002 Society of Chemical Industry
Yield stress of epoxy composites filled with quartz powder
Authors: Rubiolo Gerardo H , Marconi Jorge D , Goyanes Silvia N
Published: December 2002

The effect of the amount of quartz powder in an epoxy resin matrix was studied by compression testing. Compressive tests near room temperature and at several strain rates were performed on samples with different filler volume fractions. The data show that both the composite Young's modulus and yield stress increase with increasing volume fraction of filler. The behaviour of the composite Young's modulus follows the Lewis and Nielsen model with a value for maximum packing fraction of the filler close to that for a random packaging of quartz particles inside the epoxy matrix. In order to understand the behaviour of the yield stress, a model with physical meaning was developed. The observed strengthening effects are explained by an alternative model related to thermal internal stress.

© 2002 Society of Chemical Industry
Thermal stability of some self‐assembling hydrogen‐bonded polymers and related model complexes
Authors: Armstrong Gordon , Buggy Martin
Published: December 2002

The thermal stability of polymers is of fundamental importance both in processing and in many applications, eg, injection moulding, hot melts. As part of an investigation to determine the suitability of supramolecular polymers for novel applications in materials science, the thermal behaviour of two model compounds representing the principal classes of supramolecular polymer has been studied in some detail. p‐Methoxybenzoic acid was complexed with 1,2‐di(4‐pyridyl)ethylene in 2:1 ratio as a model compound representing liquid–crystal association chain supramolecular polymers. It is proposed that the model compound degrades as a single species obeying first‐order kinetics; the activation energy (Eact) of the degradation process was calculated to be 127 kJ mol−1. A model ureidopyrimidinone dimer degraded in two steps, also following first order kinetics, with Eact = 71.5 kJ mol−1. The dimer was unaffected by annealing, suggesting that related polymers may be used at elevated temperatures. Polymer analogues of both model compounds were synthesized and their thermal behaviour was found to parallel that of the models. In light of these results, the implications for processing both supramolecular polymers are also considered.

© 2002 Society of Chemical Industry
Structural characterization of polymer–liquid crystal dispersions
Authors: Bermudez M D , Carrion‐Vilches F J , Cervantes J J
Published: December 2002

Liquid crystalline antiwear fillers were added to thermoplastics such as polystyrene (PS), styrene–acrylonitrile copolymer (SAN) and polyamide 6 (PA). A 1 wt% proportion of thermotropic liquid crystal (LC) 4,4′‐dibutylazobenzene was added to the polymers in powder form and the mixtures were milled. In the case of PS, 10 wt% LC mixtures were also prepared. PS/LC and SAN/LC blends were compression moulded and PA/LC blends were injection moulded from the melt to obtain the modified materials. Cross sections and fracture surfaces were obtained and studied by optical and electron microscopy. Liquid crystal distribution within the polymer matrix depends on the base polymer, the additive proportion and the processing route.

© 2002 Society of Chemical Industry
Surlyn®/titanate hybrid materials via polymer in situ sol–gel chemistry
Authors: Siuzdak David A. , Start Paul R. , Mauritz Kenneth A.
Published: December 2002

Acid form Surlyn®/titanate hybrid materials were achieved by polymer in
situ sol–gel reactions for a titanium alkoxide monomer. Atomic force microscopic images revealed arrays of titania nanoparticles having diameters of 10–30 nm. Fourier transform infrared spectra verified the presence of an internally polymerized titanate phase although unhydrolyzed TiOR groups were present. Carboxylic acid dimerization was complete at room temperature, but carboxylate anions appeared at higher titanate levels. The methylene rocking doublet persisted upon incorporation of the inorganic component, which supported the idea of largely undisrupted crystallinity. Thermogravimetric analysis showed that the degradation onset temperature of each hybrid is largely unaffected by the presence of the inorganic filler, which is consistent with the concept of an isolated titanate phase. The first‐scan differential scanning calorimetric thermogram for unfilled Surlyn® revealed the usual twin‐melting endotherms. In contrast, the primary, high‐temperature melting endotherm was seen on the first scan for the Surlyn®/titanate hybrids, but the lower temperature endotherm was either not present or weak. Primary melting persisted after several cycles of heating above the melting temperature followed by cooling, demonstrating that primary crystallinity persisted despite titanate phase incorporation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 11–22, 2003
Morphology and bridging properties of (AB)nmultiblock copolymers
Authors: Rasmussen K. Ø. , Kober E. M. , Lookman T. , Saxena A.
Published: December 2002

Motivated by recent experiments (Spontak, R. J.; Smith, S. D. J Polym Sci Part B: Polym Phys 2001, 39, 947) on morphological and mechanical properties of multiblock copolymers (AB)n,we theoretically elucidate the links between microscopically determined properties, such as the bridging fraction of chains, and mechanical properties of these materials. We do this by applying self‐consistent mean‐field theory to determine morphological aspects such as period and interfacial width and calculate the bridging fractions. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 104–111, 2003
Miscibility and phase structure of binary blends of polylactide and poly(methyl methacrylate)
Authors: Zhang Guobao , Zhang Jianming , Wang Shenguo , Shen Deyan
Published: December 2002

Blends of amorphous poly(DL‐lactide) (DL‐PLA) and crystalline poly(L‐lactide) (PLLA) with poly(methyl methacrylate) (PMMA) were prepared by both solution/precipitation and solution‐casting film methods. The miscibility, crystallization behavior, and component interaction of these blends were examined by differential scanning calorimetry. Only one glass‐transition temperature (Tg) was found in the DL‐PLA/PMMA solution/precipitation blends, indicating miscibility in this system. Two isolated Tg's appeared in the DL‐PLA/PMMA solution‐casting film blends, suggesting two segregated phases in the blend system, but evidence showed that two components were partially miscible. In the PLLA/PMMA blend, the crystallization of PLLA was greatly restricted by amorphous PMMA. Once the thermal history of the blend was destroyed, PLLA and PMMA were miscible. The Tg composition relationship for both DL‐PLA/PMMA and PLLA/PMMA miscible systems obeyed the Gordon–Taylor equation. Experiment results indicated that there is no more favorable trend of DL‐PLA to form miscible blends with PMMA than PLLA when PLLA is in the amorphous state. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 23–30, 2003
Carbon black‐filled polyolefins as positive temperature coefficient materials: The effect ofin situgrafting during melt compounding
Authors: Hou Yan Hui , Zhang Ming Qiu , Rong Min Zhi
Published: December 2002

For the production of polymer‐based conducting composites serving as positive temperature coefficient (PTC) materials with lower room‐temperature resistivity and sufficiently high PTC intensity, carbon black has been pretreated with acrylic acid and some initiator and then melt‐mixed with low‐density polyethylene. Because of thein situformation of covalent bonding at the filler/matrix interface, the distribution status and thermally induced displacement habit of the conductive fillers have changed accordingly. As a result, the electrical performance of the composites can be tailored as desired. The amount of acrylic acid and the treatment sequence of carbon black exert an important influence on the effectiveness of the modification. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 127–134, 2003
Phase transition in polyamide‐66/montmorillonite nanocomposites on annealing
Authors: Liu Xiaohui , Wu Qiuju , Zhang Qingxin , Mo Zhishen
Published: December 2002

The crystalline‐phase transition in polyamide‐66/montmorillonite nanocomposites before melting was investigated by in situ X‐ray diffraction and is reported for the first time in this work. The phase‐transition temperature in the nanocomposites was 170 °C, 20 °C lower than that in polyamide‐66. The lower phase‐transition temperature of the nanocomposites could be attributed to the γ‐phase‐favorable environment caused by silicate layers. Meanwhile, the addition of silicate layers changed the crystal structure of the polyamide‐66 matrix and influenced the phase‐transition behavior. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 63–67, 2003