bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copper(II) Complexes of Schiff‐Base and Reduced Schiff‐Base Ligands: Influence of Weakly Coordinating Sulfonate Groups on the Structure and Oxidation of 3,5‐DTBC
Authors: Sreenivasulu Bellam , Vetrichelvan Muthalagu , Zhao Fei , Gao Song , Vittal Jagadese J. 
Published: October 2005

AbstractThe copper(II) complexes of the Schiff‐base ligands H2Sams and H2Saes and the reduced Schiff‐base ligands H2Sam and H2Sae formed between salicylaldehyde and aminomethanesulfonic acid or 2‐aminoethanesulfonic acid (taurine) have been synthesized in moderate yields. The solid‐statestructures of the five dinuclear complexes, [Cu2(Sams)2(H2O)2](1), [Cu2(Sam)2(H2O)2]·H2O (2), [Cu2(Saes)2(H2O)2]·2H2O (3), [Cu2(Sae)2]·2H2O (4), and [Cu2(Sae)2(DMF)2]·2DMF (5), have been determined by X‐ray crystallography, showing that the CuII centers have distorted square‐pyramidal geometry. The Schiff‐base copper complexes 1 and 3 have hydrogen‐bonded 2D sheet structures while the reduced Schiff‐base complexes 4 and 5 display a 2D coordination network and a hydrogen‐bonded 2D structure respectively. All these complexes have been investigated for their catecholase activity and activity measurements have been compared with those of dinuclear copper(II) complexes of similar ligands obtained with carboxylate analogues of the corresponding sulfonicacids; these studies show that 4 has significantly higher activity. Further, a strong antiferromagnetic interaction between CuII ions in dimeric complexes 1 [J = –9.04(2) cm–1], 3 [J = –272(4) cm–1), and 4 [J = –237(4) cm–1] has been observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Isolation and Structure Determination of Aplidinones A–C from the Mediterranean Ascidian Aplidium conicum: A Successful Regiochemistry Assignment by Quantum Mechanical 13C NMR Chemical Shift Calculations
Authors: Aiello Anna , Fattorusso Ernesto , Luciano Paolo , Mangoni Alfonso , Menna Marialuisa 
Published: October 2005

AbstractA chemical investigation of a Mediterranean ascidian, Aplidium conicum, has resulted in the isolation of the new metabolites aplidinone A (1), B (2), and C (3). The structures of aplidinones A–C were determined by interpretation of spectroscopic data, whereas the regiochemistry was determined by the comparison of experimental 13C NMR chemical shifts with those predicted by GIAO shielding calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Cover Picture: Fluorine in Peptide Design and Protein Engineering (Eur. J. Org. Chem. 21/2005)
Authors: Jäckel Christian , Koksch Beate 
Published: October 2005

AbstractThe cover picture shows the specific interaction domains (yellow: hydrophobic core; red and blue: charged functional groups in amino acid side chains) of an α‐helical coiled coil peptide (in the background) and the influence of fluoroalkyl‐substituted amino acids on the stability of hydrophobic protein cores (in the foreground). Details are presented in the Microreview by C. Jäckel and B. Koksch on p. 4483 ff.
A pull‐based service replication protocol in mobile ad hoc networks
Authors: Derhab Abdelouahid , Badache Nadjib 
Published: October 2005

AbstractThe mobility of nodes in ad hoc networks can lead to frequent network partitioning. This partitioning disconnects many nodes from a centralised server. Being aware of a future partitioning can help to provide a continuous service availability for all mobile nodes. In this paper, we propose a service replication protocol consisting of three distributed algorithms. This protocol (i) predicts the occurrence of network partitioning, which allows to create service replicas in the future separate partitions and (ii) constructs a dynamic service replicas deployment scheme. Using linear‐time temporal logic, we show that each detection of network partitioning can be predicted before its occurrence. Our simulation results show that the proposed protocol guarantees service availability to all mobile nodes without incurring high cost. Copyright © 2005 AEIT.
Independent component analysis using successive interference cancellation for oversaturated data
Authors: Huovinen Toni , Ristaniemi Tapani 
Published: October 2005

AbstractIn this paper, advanced interference cancellation strategies are considered and applied in DS‐CDMA uplink receivers. Namely, we introduce a new successive interference cancellation (SIC) scheme in which blind source separation (BSS) techniques based on independent component analysis (ICA) are considered. Our main emphasis is on the oversaturated data in which situation easily arises for example in DS‐CDMA systems when the number of active connections/users is high compared to number of chips per bit being used, that is, a highly loaded system. Proposed receiver structures combine the main benefits of pure BSS/ICA and SIC methods: (i) inherent mitigation of various types of interference sources by BSS/ICA, (ii) robustness against parameter estimation errors due to BSS/ICA, (iii) greatly improved interference suppression capability due to novel combination of SIC ideology and ICA for oversaturated data. The last item in the list can also be seen as a way to somewhat circumvent the ‘more sources than sensors’—problem, which is a challenging problem in BSS area. Numerical experiments with DS‐CDMA uplink data are given to illustrate the achieved gains in capacity and bit‐error‐rate performance compared to conventional successive and parallel interference cancellation (PIC) schemes as well as more an advanced LMMSE‐PIC receiver and variants of BSS/ICA techniques alone. Copyright © 2005 AEIT.
Capacity of dual‐branch selection diversity receivers in correlative Weibull fading
Authors: Sagias Nikos C. 
Published: October 2005

AbstractAn analysis for the Shannon channel capacity of dual‐branch selection diversity receivers operating over correlative Weibull fading is presented under three adaptive policies: constant power with optimal rate adaptation, optimal power and rate adaptation and channel inversion with fixed rate. In this context, useful formulae for the average channel capacity with not necessarily identical fading statistics and arbitrary parameters for both the correlation coefficient and fading severity are derived in closed form. The analysis also includes the performance of single‐branch receivers where special cases of the expressions agree with known results. Illustrative numerical examples are also presented, demonstrating the effects of the correlation coefficient, fading severity and signal‐to‐noise ratio unbalance on the receiver's performance. Copyright © 2005 AEIT.
Health status and labour force participation: evidence from Australia
Authors: Cai Lixin , Kalb Guyonne 
Published: October 2005

AbstractThis paper examines the effect of health on labour force participation using the Household, Income and Labour Dynamics in Australia (HILDA) Survey. The potential endogeneity of health, especially self‐assessed health, in the labour force participation equation is addressed by estimating the health equation and the labour force participation equation simultaneously. Taking into account the correlation between the error terms in the two equations, the estimation is conducted separately for males aged 15–49, males aged 50–64, females aged 15–49 and females aged 50–60. The results indicate that better health increases the probability of labour force participation for all four groups. However, the effect is larger for the older groups and for women. As for the feedback effect, it is found that labour force participation has a significant positive impact on older females' health, and a significant negative effect on younger males' health. For younger females and older males, the impact of labour force participation on health is not significant. The null‐hypothesis of exogeneity of health to labour force participation is rejected for all groups. Copyright © 2005 John Wiley & Sons, Ltd.
A microeconometric analysis of Canadian health care utilization
Authors: Sarma Sisira , Simpson Wayne 
Published: October 2005

AbstractUnderstanding health care utilization is important to design efficient and effective health systems. Toward this end, we develop a relatively simple and intutively appealing microeconometric framework to analyse health care utilization and illustrate its use with recent Canadian microdata. We find that health care utilization consists of distinct stochastic processes requiring the use of two stochastic regression models. In particular, the latent class modelling framework is the superior statistical framework if the data permit modelling unobserved heterogeneity and overdispersion. In many instances, results differ for the classes of high and low users of health care services. Copyright © 2005 John Wiley & Sons, Ltd.
Dietary and lifestyle determinants of mammographic breast density. A longitudinal study in a Mediterranean population
Authors: Masala Giovanna , Ambrogetti Daniela , Assedi Melania , Giorgi Daniela , Del Turco Marco Rosselli , Palli Domenico 
Published: October 2005

AbstractHigh mammographic breast density (H‐MBD) has been associated with increased breast cancer (BC) risk, even after adjustment for established BC risk factors. Only a few studies have examined the influence of diet on MBD. In a longitudinal study in Florence, Italy, we identified about 2,000 women with a mammogram taken 5 years after enrollment, when detailed information on dietary and lifestyle habits and anthropometric measurements had been collected. Original mammograms have been identified and retrieved (1,668; 83%), and MBD was assessed by 2 experienced readers, according to Wolfe's classification and a semiquantitative scale. By logistic analysis, we compared women with H‐MBD (P2 + DY according to Wolfe's classification) with those with low‐MBD (N1 + P1). H‐MBD was confirmed to be inversely associated with BMI, number of children and breast feeding, while it was directly associated with higher educational level, premenopausal status and a previous breast biopsy. In multivariate analyses adjusted for nondietary variables, H‐MBD was inversely associated with increasing consumption of vegetables (p for trend = 0.005) and olive oil (p for trend = 0.04). An inverse association was also evident between H‐MBD and frequent consumption of cheese and high intakes of β‐carotene, vitamin C, calcium and potassium (p for trend ≤ 0.05). On the other hand, we found a positive association with increasing consumption of wine (p for trend = 0.01). This large longitudinal study, the first carried out in Mediterranean women, suggests that specific dietary components may play a key role in determining MBD in this population, thus possibly modulating BC risk. © 2005 Wiley‐Liss, Inc.
FHIT protein enhances paclitaxel‐induced apoptosis in lung cancer cells
Authors: Kim Cheol Hyeon , Yoo Jung Sun , Lee Choon‐Taek , Kim Young Whan , Han Sung Koo , Shim Young‐Soo , Yoo Chul‐Gyu 
Published: October 2005

AbstractThe fragile histidine triad (FHIT) gene is a frequent target of deletions in lung cancer. Previous studies have shown that FHIT gene transfer into lung cancer cells lacking FHIT expression results in induction of apoptosis. However, the effect of FHIT expression on apoptosis induced by chemotherapeutic agents and its intracellular mechanism is poorly understood. This study was undertaken to elucidate the effect of FHIT expression and the role of Bcl‐2‐caspase signaling in paclitaxel‐induced apoptosis in lung cancer cells. NCI‐H358 lung cancer cells, which lack FHIT expression, were stably transfected with plasmid vector containing FLAG‐tagged wildtype FHIT. We investigated effects of paclitaxel on apoptosis, activation of caspase system and expression of Bcl‐2 family. We next evaluated whether these effects were reversed by blocking FHIT expression using siRNA. Paclitaxel enhanced apoptosis in FHIT‐expressing cells compared to that in control vector‐transfected cells, and this enhancement was suppressed by siRNA treatment. Activities of caspase‐3 and caspase‐7, but not of caspase‐8, were higher in FHIT‐expressing cells than in control vector‐transfected cells, and this was reduced by siRNA treatment. When caspase activation was blocked by a pan‐caspase inhibitor in FHIT‐expressing cells, paclitaxel‐induced apoptotic cell death was decreased similar to that in control vector‐transfected cells. Bcl‐2 and Bcl‐xL expressions were down‐regulated after paclitaxel treatment in FHIT‐expressing cells, whereas Bax and Bad expressions were up‐regulated. These were reversed by siRNA treatment. These results indicate that paclitaxel‐induced apoptosis enhanced by FHIT expression in lung cancer cells might be associated with modulation of Bcl‐2‐caspase signaling. © 2005 Wiley‐Liss, Inc.
Daily timed meals dissociate circadian rhythms in hepatoma and healthy host liver
Authors: Davidson Alec J. , Straume Martin , Block Gene D. , Menaker Michael 
Published: October 2005

AbstractDividing cells, including human cancers, organize processes necessary for their duplication according to circadian time. Recent evidence has shown that disruption of central regulation of circadian rhythms can increase the rate at which a variety of cancers develop in rodents. To study circadian rhythms in liver tumors, we have chemically induced hepatocellular carcinoma in transgenic rats bearing a luciferase reporter gene attached to the promoter of a core circadian clock gene (Period 1). We explanted normal liver cells and hepatomas, placed them into short‐term culture, and precisely measured their molecular clock function by recording light output. Results show that isolated hepatocellular carcinoma is capable of generating circadian rhythms in vitro. Temporally restricting food availability to either day or night altered the phase of the rhythms in both healthy and malignant tissue. However, the hepatomas were much less sensitive to this signal resulting in markedly different phase relationships between host and tumor tissue as a function of mealtime. These data support the conclusion that hepatoma is differentially sensitive to circadian timing signals, although it maintains the circadian organization of the nonmalignant cells from which it arose. Because circadian clocks are known to modulate the sensitivity of many therapeutic cytotoxic targets, controlling mealtiming might be used to increase the efficacy of treatment. Specifically, meal and treatment schedules could be designed that take advantage of coincident times of greatest tumor sensitivity and lowest sensitivity of host tissue to damage. © 2005 Wiley‐Liss, Inc.
MALDI‐TOF MS characterization of proanthocyanidins from cranberry fruit (Vaccinium macrocarpon) that inhibit tumor cell growth and matrix metalloproteinase expression in vitro
Authors: Neto Catherine C , Krueger Christian G , Lamoureaux Toni L , Kondo Miwako , Vaisberg Abraham J , Hurta Robert AR , Curtis Shannon , Matchett Michael D , Yeung Horace , Sweeney Marva I , Reed Jess D 
Published: October 2005

AbstractProanthocyanidin‐rich extracts were prepared by fractionation of the fruit of the North American cranberry (Vaccinium macrocarpon). In vitro growth inhibition assays in eight tumor cell lines showed that selected fractions inhibited the growth of H460 lung tumors, HT‐29 colon and K562 leukemia cells at GI50 values ranging from 20 to 80 µg ml−1. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) of one of these fractions found it to be composed of polyflavan‐3‐ols, which are primarily tetramers through heptamers of epicatechin containing one or two A‐type linkages. Whole cranberry extract and the proanthocyanidin fractions were screened for effect on the expression of matrix metalloproteinases in DU 145 prostate carcinoma cells. The expression of MMP‐2 and MMP‐9 was inhibited in response to whole cranberry extract and to a lesser degree by the proanthocyanidin fractions. Copyright © 2005 Society of Chemical Industry
Rod‐Length Dependent Aggregation in a Series of Oligo(p‐benzamide)‐Block‐Poly(ethylene glycol) Rod‐Coil Copolymers
Authors: Abbel Robert , Schleuss Tobias W. , Frey Holger , Kilbinger Andreas F. M. 
Published: October 2005

AbstractSummary:The synthesis of a series of rod‐coil diblock copolymers with flexible poly(ethylene oxide) chains ($\overline M _{\rm n}$ = 5 000 g · mol−1) and rod blocks consisting of monodisperse oligo(p‐benzamide)s is described. The formation of defined supramolecular aggregates in solution as well as the solid state has been analyzed. The length of the oligo(p‐benzamide)s has been systematically varied fromn = 1 to 7 units. The influence ofnon aggregation in chloroform and aqueous solution was investigated by GPC as well as UV‐vis spectroscopy. A critical aggregation length was found for chloroform (n = 5) and water (n = 4), below which no aggregation is observed under otherwise identical experimental conditions. Aggregation of the polymers in chloroform solution can be chemically reversed by the addition of PCl5, resulting in conversion of the aromatic amides into imidoyl chlorides. Such amide‐protected block copolymers show no aggregation in NMR and GPC experiments. Imidoyl chloride formation was shown to be reversible, i.e., addition of water regenerated the oligo(p‐benzamide) blocks.Conversion of aramide block copolymer into molecularly dissolved form using PCl5.magnified imageConversion of aramide block copolymer into molecularly dissolved form using PCl5.
Epoxy Resin Containing Octamaleimidophenyl Polyhedral Oligomeric Silsesquioxane
Authors: Ni Yong , Zheng Sixun 
Published: October 2005

AbstractSummary: Octamaleimidophenyl polyhedral oligomeric silsesquioxane (OmipPOSS) was synthesized via the imidization reaction between octaaminophenyl polyhedral oligomeric silsesquioxane (OapPOSS) and maleic anhydride, and it was characterized by means of Fourier transform infrared (FTIR) and NMR spectroscopies. OmipPOSS was further employed to prepare epoxy hybrids. The thermosetting hybrids containing OmipPOSS up to 10 wt.‐% were obtained via in situ polymerization of diglycidyl ether of bisphenol A (DGEBA) and 4,4′‐diaminodiphenylmethane (DDM) in the presence of OmipPOSS. High‐resolution transmission electronic microscopy (TEM) indicates that the nanometer‐scaled dispersion of POSS molecules was obtained, suggesting that the nanocomposites were successfully prepared. The results of DSC showed that the glass transition temperatures (Tg's) of the POSS‐containing nanocomposites are dependent on the content of POSS in the nanocomposites. When the contents of POSS are less than 5 wt.‐%, the nanocomposites displayed the enhanced glass transition temperatures (Tg's) in comparison with control epoxy. Thermogravimetric analysis (TGA) showed that all the nanocomposites containing POSS displayed improved char yield, suggesting the flame retardance of the materials is improved.
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Efficient Synthesis and Copolymerization of Poly(acrylic acid) and Poly(acrylic ester) Macromonomers: Manipulation of Steric Factors
Authors: McHale Ronan , Aldabbagh Fawaz , Carroll William M. , Yamada Bunichiro 
Published: October 2005

AbstractSummary: Macromonomers have been prepared by polymerization of acrylic acid (AA) and tert‐butyl acrylate (tBA) in the presence of the addition‐fragmentation chain transfer (AFCT) agents, ethyl α‐(bromomethyl)acrylate (EBMA) and tert‐butyl α‐(bromomethyl)acrylate (BBMA). Chain transfer constants of 1.25 (EBMA) and 1.14 (BBMA) in the AA polymerization, and 2.42 (EBMA) and 1.75 (BBMA) in the tBA polymerization were obtained. The reduction in molecular weight with increasing concentration of AFCT agent and efficient introduction of 2‐carbalkoxy‐2‐propenyl ω‐end group was indicative of macromonomer formation. Polymerizations were retarded with increasing concentrations of AFCT agent and increases in the absolute concentration of EBMA slowed down the polymerization of AA but not tBA. The difference between EBMA and BBMA was less significant with tBA; more efficient macromonomer synthesis was indicated by less retardation and greater double bond retention at higher conversions. Copolymerizations of poly(AA) and poly(tBA) macromonomers with styrene indicated that the former was more reactive towards the St propagating radical. The results are rationalized in terms of the steric hindrance imposed by the tert‐butyl group. Poly(tBA) macromonomer was successfully hydrolyzed to give an alternative route to the poly(AA) macromonomer.Reaction mechanism for macromonomer synthesis using AFCT.magnified imageReaction mechanism for macromonomer synthesis using AFCT.
Controlling the Thermosensitive Gelation Properties of Poly(organophosphazenes) by Blending
Authors: Kang Gyung Don , Heo Jeong‐Yun , Jung Sung Bum , Song Soo‐Chang 
Published: October 2005

AbstractSummary: After synthesizing both hard poly(organophosphazenes), which acted as strong hydrogels at a temperature below 37 °C, and soft poly(organophosphazenes), which displayed the opposite properties, we blended the polymers. When these polymers were blended at an appropriate ratio, the blended aqueous solution changed into a transparent hydrogel with improved mechanical properties at a temperature of 37 °C. According to DSC and IR measurements, the two polymers blended homogeneously and exhibited a behavior characteristic of a completely different copolymer.An aqueous poly(organophosphazene) solution at room temperature (left) is reversibly and rapidly transformed into a transparent hydrogel at body temperature (right) when a hard poly(organophosphazene) is blended with a soft one at an appropriate ratio.imageAn aqueous poly(organophosphazene) solution at room temperature (left) is reversibly and rapidly transformed into a transparent hydrogel at body temperature (right) when a hard poly(organophosphazene) is blended with a soft one at an appropriate ratio.
Modeling and Sensitivity Analysis of Particle Size Distribution and Chain Length Distribution in a Semibatch Emulsion Copolymerization Reactor
Authors: Park Myung‐June , Dokucu Mustafa T. , Doyle Francis J. 
Published: October 2005

AbstractSummary: A comprehensive model is developed to predict the relationship between the particle size distribution and molecular weights of particles in an emulsion copolymerization reactor. A full population balance equation is used for the particle size distribution and extended to the model for the molecular properties using a continuous reactor approach. The numerical prediction clearly distinguishes the characteristics of molecular properties of particles by homogeneous nucleation from those by micellar nucleation with the dependence on the particle size. Sensitivity analysis of the proposed model under a variety of conditions shows that the compartmentalized feature of the emulsion system should be considered for better prediction of molecular properties, and provides information on the manipulated variables and lumped parameters which effectively decompose the correlation of both properties. Finally, a control strategy utilizing a lumped parameters tracking method is suggested for the regulation of both the particle size distribution and molecular properties.Time evolution of number‐averaged molecular weights in the element under base conditions.magnified imageTime evolution of number‐averaged molecular weights in the element under base conditions.