bluuebunny/crossref_metadata_2025 huggingface dataset:
A Chronological Decrease in Type A Behavior Patterns among Japanese Male Workers in 1995–1999
Authors: Kojima Masayo , Nagaya Teruo , Takahashi Hidekatsu , Kawai Makoto , Tokudome Shinkan
Published: April 2004

A Chronological Decrease in Type A Behavior Patterns among Japanese Male Workers in 1995–1999: Masayo Kojima, et al. Department of Health Promotion and Preventive Medicine, Nagoya City University Graduate School of Medical Sciences—We examined the chronological change in Type A behavior pattern (TABP) among Japanese male workers for 5 yr. A brief questionnaire to measure TABP was administered to 21,711 male workers who underwent health check‐ups at least once during the period from 1995 to 1999 and were born in 1936–1965. The mean TABP scores decreased year by year linearly. Then the repeated measurement analysis of variance was performed with the data of 5,689 subjects who completed the questionnaire successively through the study period. Both year and the age effects were highly significant (p<0.001, respectively), whereas the time trends were comparable by baseline age. In conclusion, TABP among Japanese male workers decreased in all generations during the period from 1995 to 1999.
Carcinogenicity and Chronic Toxicity in Mice and Rats Administered Vinyl Acetate Monomer in Drinking Water
Authors: Umeda Yumi , Matsumoto Michiharu , Yamazaki Kazunori , Ohnishi Makoto , Arito Heihachiro , Nagano Kasuke , Yamamoto Seigo , Matsushima Taijiro
Published: April 2004

Carcinogenicity and Chronic Toxicity in Mice and Rats Administered Vinyl Acetate Monomer in Drinking Water: Yumi Umeda, et al. Japan Bioassay Research Center, Japan Industrial Safety and Health Association—Carcinogenicity and chronic toxicity of vinyl acetate monomer (VA) were examined in male and female Crj:BDF1 mice and F344/DuCrj Rats. Groups of 50 mice and 50 rats of each sex were orally administered VA in drinking water containing 0, 400, 2,000 or 10,000 ppm (g/g) VA for 104 wk. Squamous cell tumors were clearly evident in the upper digestive tract of treated mice and rats, and in the larynx of treated mice of both sexes. In mice, squamous cell carcinomas and papillomas were observed in the oral cavity, esophagus, forestomach and larynx of the 10,000 ppm group, together with basal cell hyperplasia, squamous cell hyperplasia and epithelial dysplasia. In rats, incidences of squamous cell carcinomas and papillomas were increased in the oral cavity of the 10,000 ppm group of both sexes, and an esophagus squamous cell carcinoma was observed in a 10,000 ppm female. Pre‐neoplastic hyperplasias were also noted. Mapping of the neoplastic and pre‐neoplastic lesions in the oral cavity of the 10,000 ppm group revealed that both the lesions occurred predominantly at Level V in mice and at Level VI in rats. A lower confidence limit of a benchmark dose (BMDL10) of 477 mg/kg/d was obtained from a dose‐response relationship between combined incidence of squamous cell carcinomas and papillomas in the oral cavity of mice and rats and the estimated daily VA intakes per body weight, and compared with literature values.
External thought—does sketching assist problem analysis?
Authors: Sachse Pierre , Hacker Winfried , Leinert Sven
Published: April 2004

An experimental study (n = 60 students) tests the advantages of being allowed to sketch a representation of a mechanical system (involving components such as weights, ropes and pulleys) when one is to be subsequently asked questions about this system. In comparison to a control group who were not allowed to sketch the system, the main advantages of sketching were found to be a reduction in the perceived difficulty of the problems and an increase in the likelihood of correctly inferring relations between the components. These advantages came at no extra cost in terms of additional time being needed to analyse the situation or solve the problems. However, sketching conferred no advantage in terms of the correct recall of system components. Copyright © 2004 John Wiley & Sons, Ltd.
Quantum‐Chemical Studies on the Geometric and Electronic Structures of Bertholloide Cobalt Oxynitrides
Authors: Lumey M.‐W. , Dronskowski R.
Published: April 2004

We report electronic structure calculations using density‐functional theory (local density approximation (LDA) and generalized gradient approximation (GGA); plane waves and muffin‐tin orbitals; pseudopotentials and all‐electron approaches) on non‐stoichiometric CoNxO1–x oxynitride phases. The preference of the experimentally suggested zinc‐blende structure type over the rock‐salt type is confirmed and explained, on the basis of COHP (crystal orbital Hamilton population) chemical bonding analyses, by reduced Co–Co antibonding interactions in the ZnS structural alternative. A pressure‐induced phase transition into the NaCl type, however, is predicted at approximately 30 GPa. Supercell calculations touching upon the exact composition and local structure of CoNxO1–x provide evidence for a broad range of energetically metastable compositions with respect to the zinc‐blende‐type boundary phases CoN and CoO, especially for the more oxygen‐rich phases. All non‐stoichiometric compounds are predicted to be metallic materials which do not exhibit significant magnetic moments. Likewise, there is no indication for anionic ordering such that random anion arrangements are preferred.
The Regioisomeric Triphenylaminoethanols –Comparison of their Efficiency in Enantioselective Catalysis
Authors: Braun Manfred , Fleischer Ralf , Mai Brigitte , Schneider Marc‐André , Lachenicht Stefan
Published: April 2004

Both enantiomers of the novel amino alcohol (R)‐ and (S)‐2 are prepared from the corresponding enantiomer of the mandelic acid‐derived ethanediol 3. The regioisomeric amino alcohols 1 and 2 are converted into the imines 7 and 8, respectively. Titanium complexes 9 and 10 derived therefrom are used as catalysts for the addition of diethylzinc to benzaldehyde and yield the alcohol 11 in up to 92% ee. On the other hand, the chloro‐substituted titanium complexes 14 and 15 are able to mediate the Torgov cyclization reaction of the diketone 16 to give the estrone derivative 17. In both reactions titanium complexes 10 and 15 derived of the novel amino alcohol 2 give higher enantioselectivities than the complexes 9 and 14 that are based on the regioisomeric amino alcohol 1.
High‐Pressure 31P{1H} NMR Studies of RhH(CO)(TPPTS)3 in the Presence of Methylated Cyclodextrins: New Light on Rhodium‐Catalyzed Hydroformylation Reaction Assisted by Cyclodextrins
Authors: Monflier E. , Bricout H. , Hapiot F. , Tilloy S. , Aghmiz A. , Masdeu‐Bultó A. M.
Published: April 2004

The effect of methylated cyclodextrins on the RhH(CO)(TPPTS)3 complex in hydroformylation conditions [50 atm of CO/H2 (1/1) and 80 °C] has been investigated by high‐pressure 31P{1H} NMR spectroscopy. In the presence of methylated β‐cyclodextrin, the equilibria between the rhodium species lie in favor of phosphine low‐coordinated rhodium species. The formation of a stable inclusion complex between this cyclodextrin and the trisulfonated triphenylphosphine ligand (TPPTS) was found to be the key to understanding the displacement of the equilibria. Indeed, the methylated α‐cyclodextrin which does not interact with the TPPTS and the methylated γ‐cyclodextrin which can weakly bind to the TPPTS have no and a very low effect on the equilibria, respectively. These results explain for the first time why a decrease in the normal to branched aldehydes ratio is always observed when cyclodextrins are used as mass‐transfer agents in aqueous biphasic hydroformylation processes.
Preparation of the Novel Mesoporous Solid Acid Catalyst UDCaT‐4 via Synergism of Persulfated Alumina and Zirconia into Hexagonal Mesoporous Silica for Alkylation Reactions
Authors: Yadav Ganapati D. , Murkute Ambareesh D.
Published: April 2004

A novel mesoporous solid acid catalyst named UDCaT‐4 was designed by loading persulfated alumina and zirconia (PAZ) into highly oredered, hexagonal mesoporous silica (HMS). UDCaT‐4 was characterized by XRD, BET surface area and pore size analysis which revealed that neither pore blocking nor structure collapse of HMS had occurred. NH3‐TPD and FTIR were used to determine the acid strength and nature of the sulfate ion retained on the surface of UDCaT‐4. It is known that HCl and water have detrimental effects on the activity of the zirconia‐based catalyst. Hence, the activity of UDCaT‐4 was evaluated in comparsion with that of bulk PAZ in the liquid‐phase alkylation of toluene with benzyl chloride and also in the vapour‐phase alkylation of mesitylene with isopropanol, where acid and water are generated in‐situ, respectively, as co‐products. The superior catalytic acivity of UDCaT‐4 is atributed to the uniform dispersion of the superacidic centers of PAZ into HMS vis‐à‐vis bulk PAZ. Reusability and time on‐stream studies reveal that UDCaT‐4 is a robust and reusable catalyst even in the presence of HCl and H2O.
Efficient Biocatalytic Synthesis of Highly Enantiopure α‐Alkylated Arylglycines and Amides
Authors: Wang Mei‐Xiang , Lin Shuan‐Jun , Liu Jun , Zheng Qi‐Yu
Published: April 2004

A number of racemic α‐alkylarylglycine amides including 1‐amino‐1‐carbamoyl‐1,2,3,4‐tetrahydronaphthalene underwent efficient biocatalytic hydrolysis under very mild conditions to afford the corresponding (S)‐α‐alkylarylglycines and (R)‐α‐alkylarylglycine amides in excellent yields with enantiomeric excesses higher than 99.5%. Both the reaction rate and enantioselectivity of biocatalytic kinetic resolution were strongly dependent upon the nature of the substituent and the substitution pattern on the benzene ring of the substrate. In contrast, no effective biotransformation of the Strecker nitrile derived from acetophenone was observed under the catalysis of a nitrile hydratase/amidase‐containing microbial Rhodococcus sp. AJ270 whole‐cell catalyst. Coupled with the chemical hydrolysis of amide, this biotransformation process provided efficient syntheses of α‐substituted arylglycines in both enantiomeric forms from readily available racemic amides.
Optimal bimodal pore networks for heterogeneous catalysis
Authors: Gheorghiu Stefan , Coppens Marc‐Olivier
Published: April 2004

A practical problem in the rational design of a heterogeneous catalyst is to optimize its structure at all scales. By optimizing the large‐pore network of a bimodal porous catalyst with a given nanoporosity (for example, zeolite or mesoporous catalyst) for the yield of diffusion‐limited first‐order reactions, it is found that catalysts typically benefit from a hierarchical pore network with a broad pore‐size distribution. When comparing the performance of the optimal structures to that of self‐similar, fractal‐like pore hierarchies, it is found that the latter can be made to have the same effectiveness factor as the optimal ones, suggesting that fractal‐like catalysts operate very near optimality, even if their structure is considerably different from that of the true optima. This is useful, because fractal‐like structures have the advantage of being organized in a modular, natural way, potentially easy to reproduce by templating. © 2004 American Institute of Chemical Engineers AIChE J, 50: 812–820, 2004
Lead effect on blood pressure in moderately lead‐exposed male workers
Authors: Telišman Spomenka , Pizent Alica , Jurasović Jasna , Cvitković Petar
Published: April 2004

Background

The effect of lead (Pb) and potential confounding variables on blood pressure was examined in healthy male industrial workers 20–43 years of age.

Methods

In 100 Pb workers and 51 reference subjects, the following variables were measured: blood Pb (BPb), activity of δ‐aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), blood cadmium (BCd), serum zinc (SZn), serum copper (SCu), hematocrit (Hct), body mass index (BMI), and blood pressure. The inter‐relationship of biomarkers of Pb (BPb, ALAD, EP) and BCd, SZn, SCu, Hct, BMI, age, smoking, and alcohol to systolic and diastolic blood pressure was calculated by forward stepwise multiple regression.

Results

There was no significant difference in blood pressure between the two groups, possibly because the reference subjects had relatively high BPb levels and significantly higher BMI (P < 0.05) as compared to the Pb workers. According to the multiple regression results in Pb workers, an increase in systolic blood pressure was significantly associated with increasing EP (P = 0.001) and BMI (P < 0.002), or alternatively with increasing BMI (P < 0.004) and decreasing ALAD (P < 0.04) and BCd (P < 0.05). An increase in diastolic blood pressure was significantly associated with increasing BMI (P < 0.009) and EP (P = 0.05) and decreasing BCd (P < 0.04). With respect to the EP range of 0.73–13.94 µmol/l erythrocytes in 100 Pb workers, an increase of 17 mm Hg in systolic and 6 mm Hg in diastolic blood pressure was found.

Conclusions

Long‐term cumulative Pb exposure, which is better reflected by EP than by ALAD or current BPb level, can significantly increase blood pressure in moderately Pb‐exposed male workers (long‐term average BPb <400 µg/l; exposure duration 2–21 years). Am. J. Ind. Med. 45:446–454, 2004. © 2004 Wiley‐Liss, Inc.
Contribution of malformations and genetic disorders to mortality in a children's hospital
Authors: Stevenson David A. , Carey John C.
Published: April 2004

Malformations and genetic disorders are the leading cause of infant mortality in the US. Many malformations have a genetic basis due to genic, chromosomal, or multifactorial causation. We have studied the proportion of pediatric cases in a university‐affiliated children's hospital that died of malformations and genetic disorders. We reviewed, retrospectively, deaths over a 4 year period (1994–1998) at Primary Children's Medical Center (PCMC), a university‐affiliated tertiary children's referral hospital in Utah. The age at death and the cause of death were recorded for each case. We analyzed 523 cases; 180 (34.4%) deaths were due to malformations and genetic disorders. Of those 180, 30 (16.7%) had chromosome anomalies, 21 (11.7%) had a recognizable malformation syndrome, 118 (65.6%) had a malformation of unknown cause, and 11 (6.1%) had some other genetic disorder. One hundred and twenty‐two (23.3%) deaths were due to trauma (accidental and non‐accidental). Seventy‐nine (15.1%) deaths were due to short gestation or perinatal complications. Forty‐five (8.6%) deaths were due to an infectious disease and 45 (8.6%) from neoplasms. Thirteen (2.5%) were diagnosed for sudden infant death “syndrome.” Twelve (2.3%) patients with malformations and/or genetic disorders died of an acquired condition not clearly related to the underlying disorder. Seven (1.3%) patients died of an unknown cause and 20 (3.8%) patients died of other specified conditions. In addition, 51.0% patients (age <1 year) died of a malformation and/or genetic disorder. Genetic disorders and malformations are a substantial cause of mortality in a referral pediatric hospital. Knowledge of the impact of genetic diseases on mortality is important for the integration of preventive measures and health care strategies to care effectively for patients and their families. This information emphasizes the importance of further study of whether or not early recognition influences mortality rate and management. © 2003 Wiley‐Liss, Inc.
Prenatal diagnosis of a rare inherited heterochromatic variant chromosome 4
Authors: Zaslav Ann‐Leslie , Pierno Guy , Fougner Arthur , Jacob Jessy , Shikora Geraldine , Kazi Rehana , Blumenthal Donna , Alexander Fakhry , Fox Joyce E.
Published: April 2004

Heterochromatic chromosome polymorphisms have been extensively reported. Most are associated with C‐band positive regions located on chromosomes 1, 9, 16, and Y. We report a prenatal case of a rare heterochromatic variant on chromosome 4. Amniocentesis was performed on a 35‐year‐old white female for AMA. The karyotype was 46,XY,add(4)(q35)?. One chromosome 4 homolog had an additional dark band at the terminus of the long arm. Parental chromosome analyses revealed that the chromosome 4 was maternally inherited. The mother and fetus were both Q and C‐band positive and NOR and DAPI Distamycin staining negative. FISH using Y, 4, and 9 whole chromosome paint (WCP), centromere probes for all chromosomes (Cytocell, Chromoprobe Multiprobe‐I System, Rainbow Scientific, Inc., Windsor, CT), alpha‐satellite probes for 13/21, 14/22 (D13Z1/D21Z1; D14Z1/D22Z1, Oncor, Gaithersburg, MD), and the 15 PWS/Angelman probe (LSI SNRPN, D15Z1, PML, Vysis, Inc., Downers Grove, IL) were negative. The TelVysion 4q telomere probe (D4S2930, Vysis, Inc.) was positive. A phenotypically normal male was born at 37 weeks. Follow up studies on placenta, cord, cord blood, and foreskin confirmed the prenatal results. Based on these findings, it appears that this chromosome 4 was a rare heterochromatic variant. Heterochromatic variants have been demonstrated to have no phenotypic effect on carriers. This case illustrates the importance of reporting unusual variant chromosomes for genetic counseling purposes. To the best of our knowledge, this is the first report of a heterochromatic variant involving part of the long arm of chromosome 4 in a phenotypically normal mother and child. © 2003 Wiley‐Liss, Inc.
Familial interstitial duplication of 11q; partial trisomy (11)(q13.5q21)
Authors: Yelavarthi Krishna K. , Zunich Janice
Published: April 2004

We report on a case of an interstitial duplication of 11q in a patient with developmental delay and in his moderately delayed mother. Partial trisomy 11q is well documented in the literature with most cases involving the distal region of the long arm of chromosome 11. In almost all cases, this trisomy is associated with monosomy of the second chromosome involved in the parental translocation. The most common, partial 11q and 22q trisomy syndrome, is observed in offspring of t(11;22)(q23;q11.2) carriers from a 3:1 tertiary trisomic malsegregation. We found only two previous reports of pure partial trisomy 11q in the literature. Comparison of the clinical findings of our patient and another single published report of duplication in the same segment of chromosome 11 suggests that the duplication of this region manifests mild phenotypic abnormalities. © 2003 Wiley‐Liss, Inc.
Two new cases of Barraquer–Simons syndrome
Authors: Ferrarini A. , Milani D. , Bottigelli M. , Cagnoli G. , Selicorni Angelo
Published: April 2004

Barraquer–Simons syndrome is a rare form of partial lipodystrophy, mainly characterized by loss of subcutaneous tissue, starting from the face and spreading to the upper part of the body. Occasional functional anomalies such as deafness, epilepsy, and mental retardation can be associated with the condition; nephropathy and myopathy have been observed occasionally. Here we report on two new sporadic cases, who show at the moment only a facial involvement, without any associated anomalies and/or medical complications. © 2003 Wiley‐Liss, Inc.
Response to social challenge in young bonnet (Macaca radiata) and pigtail (Macaca nemestrina) macaques is related to early maternal experiences
Authors: Weaver Ann , Richardson Rebecca , Worlein Julie , Waal Frans De , Laudenslager Mark
Published: April 2004

Previous experience affects how young primates respond to challenging social situations. The present retrospective study looked at one aspect of early experience, the quality of the mother‐infant relationship, to determine its relationship to young bonnet and pigtail macaques' responses to two social challenges: temporary maternal separation at 5‐6 months and permanent transfer to an unfamiliar peer group at 16–17 months. Relationship quality was measured quantitatively on 30 macaque mother‐infant pairs with the Relationship Quality Index (RQI), the ratio of relative affiliation to relative agonism as previously applied to capuchin monkeys. Infants with high RQI values had amicable mother‐infant relationships and infants with low RQI values had agonistic mother‐infant relationships. Young monkeys with amicable and agonistic relationships showed consistent differences in behavior before, during, and after each social challenge, supporting the hypothesis that juveniles from amicable mother‐infant relationships based on the RQI coped more effectively with social challenges than did juveniles from agonistic mother‐infant relationships. Results suggest 1) characteristic amicability or agonism in early mother‐offspring macaque relationships has the potential to influence offspring behavior in tense social contexts and 2) the RQI is useful as one of a coordinated suite of methods for studying the development of social skills. Am. J. Primatol. 62:243–259, 2004. © 2004 Wiley‐Liss, Inc.
Mating system of an exceptional primate, the olive colobus (Procolobus verus)
Authors: Korstjens Amanda H. , Noë Ronald
Published: April 2004

In the olive colobus (Procolobus verus), many groups have multiple males and the males have large testes. This indicates that even though this species lives in small groups, single males do not monopolize the groups. We investigated the strategies employed by males to secure their mating success, and sought to determine whether the lack of male monopolization was a result of female mating strategies, as indicated by the exaggerated sexual swellings of the females. Four study groups were monitored for demographic changes, and group composition was determined in six additional groups in Taï National Park, Ivory Coast, between 1994 and 1999. Social behavior was recorded by scan and focal sampling in the study groups. The almost permanent association of olive colobus with Diana monkeys (Cercopithecus diana) in effect provided males a resource at which they could expect females to visit and sometimes even permanently join them, as well as protection from predators. As alternative strategies for obtaining females, one male took over the group of another male and one male immigrated into a bisexual group. Within bi‐male groups, dominant males mated most frequently and males defended their groups during intergroup interactions. Lone females that visited groups or solitary males had a swelling more often than expected, and generally mated with the males they visited. Females had long receptive periods, several consecutive receptive cycles, and some overlap in receptive periods within groups. Females mated with extragroup males, and during infertile periods. We concluded that the males used the Diana monkeys for safety reasons and to obtain mating partners, and that female reproductive biology and behavior prevented the monopolization of groups of females by single males. Our data were inconclusive as regards the benefits to females of avoiding monopolization by males. Am. J. Primatol. 62:261–273, 2004. © 2004 Wiley‐Liss, Inc.
Relationships between the fossil colobine Mesopithecus pentelicus and extant cercopithecoids, based on dental metrics
Authors: Pan Ruliang , Groves Colin , Oxnard Charles
Published: April 2004

Maxillary dental measurements from six specimens of Mesopithecus pentelicus, 64 cercopithecines, 59 African colobines, and 64 Asian colobines were analyzed by means of a “nested research design” that was specifically designed to explore the affiliation between fossils and extant cercopithecoids at different systematic levels. The results showed that the variation among taxonomic groups was mainly associated with size; however, in addition, interesting shape differences emerged, molars were shown to be important discriminators, Mesopithecus was confirmed as a colobine (as expected) and found to be closer to Asian species than to African ones, and the odd‐nosed colobines were found to share more dental similarities with Mesopithecus than other colobines. The last finding is in contrast to previous studies, in which it was proposed that M. pentelicus is morphologically closely related to the African colobus and the gray langur (Semnopithecus) in Am. J. Primatol. 62:287–299, 2004 © 2004 Wiley‐Liss, Inc.
Comparison of the failure conditions for creep, stress relaxation, and constant strain rate measurements to predict pipe burst for two ABS materials using the universal viscoelastic model
Authors: Sudduth Richard D.
Published: April 2004

The universal viscoelastic model was further validated in this study using two acrylonitrile–butadiene–styrene (ABS) viscoelastic materials to better elucidate the direct relationship between the failure criterion characteristics involving creep, constant strain rate, stress relaxation, and pipe burst. Using the yield strain as the failure criterion for constant strain rate and stress relaxation measurements and the strain at critical creep, the failure condition for creep, it was found that the universal viscoelastic model allowed these failure criteria to yield remarkably good agreement on a projected time scale. The relationship of the failure criteria between these three different techniques for characterizing a viscoelastic material was successfully used to identify several complementary approaches to predict long‐term pipe burst for two different ABS materials. The pipe burst data for ABS‐A appeared to fit the Tresca failure criterion better than the von Mises failure criterion, as predicted from failure criteria using constant strain rate, creep, and stress relaxation measurements. For ABS‐A the extrapolated creep and the constant strain rate failure criterion appeared to best predict the Tresca failure criterion pipe burst data. However, the hoop burst stress for ABS‐N, adjusted with the von Mises failure criterion modification, was found to give the best agreement with the yield stress equivalent failure criterion for constant strain rate, creep, and stress relaxation. For ABS‐N, the extrapolated creep failure criteria appeared to best predict the von Mises pipe burst failure criterion. In this study, the relationships between the failure criteria for the three different experimental techniques of constant strain rate, creep, and stress relaxation were shown to be reasonably interchangeable relative to a three‐dimensional failure configuration such as pipe burst. Because this interchangeability approach was found to work so well in the laboratory, there is no reason to believe that this same technique, using the universal viscoelastic model, would not also work as well to predict failure criteria for design applications using finite‐element analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 247–260, 2004
Kinetics and mechanism of initial steps of synthesis of polyetherols from melamine and ethylene carbonate
Authors: Kijowska Dorota , Wołowiec Stanisław , Lubczak Jacek
Published: April 2004

The kinetics of initial steps of formation of polyetherols in the reaction between melamine and ethylene carbonate in dimethylsulfoxide in presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) as catalyst was studied. Based upon kinetic studies performed with various concentrations of melamine and catalyst, the rate law was formulated and a mechanism of the reaction was proposed. The activation parameters ΔG#, ΔH#, and ΔS# were obtained from the temperature dependence of kinetics. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 294–300, 2004
Study on a new kind of polypropylene‐graft‐ polystyrene: Preparation and application
Authors: Li Ze , Ke Yucai , Hu Youliang
Published: April 2004

A novel synthetic route for preparing polypropylene‐graft‐polystyrene (PP‐g‐PSt) was set up. With this synthetic route, a series of PP‐g‐PSt copolymers containing different percentages of polystyrene chain were synthesized, based on the different reactivities of two kinds of CC double bonds on 4‐(3‐butenyl) styrene. Characterization data, including 1H‐NMR, 13C‐NMR, GPC, and DSC, demonstrated that the graft copolymers were all very pure. Furthermore, it was also attempted to use this new kind of propylene–styrene graft copolymer as a compatibilizer. DMA and SEM results illustrated that the PP‐g‐PSt obtained is an efficient compatibilizer for the polypropylene–polystyrene blend. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 314–322, 2004
Searching the peer‐to‐peer networks: The community and their queries
Authors: Ho Kwok Sai , Yang Christopher C.
Published: April 2004

Peer‐to‐Peer (P2P) networks provide a new distributed computing paradigm on the Internet for file sharing. The decentralized nature of P2P networks fosters cooperative and non‐cooperative behaviors in sharing resources. Searching is a major component of P2P file sharing. Several studies have been reported on the nature of queries of World Wide Web (WWW) search engines, but studies on queries of P2P networks have not been reported yet. In this report, we present our study on the Gnutella network, a decentralized and unstructured P2P network. We found that the majority of Gnutella users are located in the United States. Most queries are repeated. This may be because the hosts of the target files connect or disconnect from the network any time, so clients resubmit their queries. Queries are also forwarded from peers to peers. Findings are compared with the data from two other studies of Web queries. The length of queries in the Gnutella network is longer than those reported in the studies of WWW search engines. Queries with the highest frequency are mostly related to the names of movies, songs, artists, singers, and directors. Terms with the highest frequency are related to file formats, entertainment, and sexuality. This study is important for the future design of applications, architecture, and services of P2P networks.
Topic modeling for mediated access to very large document collections
Authors: Muresan Gheorghe , Harper David J.
Published: April 2004

Clear and precise queries are a necessity when searching very large document collections, especially when query‐based retrieval is the only means of exploration. We propose system‐mediated information access as a solution for users' well‐documented inability to formulate good queries. Our approach is based on two main assumptions: first, on the ability of document clustering to reveal the topical, semantic structure of a problem domain represented by a specialized “source collection,” and, second, on the capacity of statistical language models to convey content. Taking the role of the human mediator or intermediary searcher, a mediation system interacts with the user and supports her exploration of a relatively small source collection, chosen to be representative for the problem domain. Based on the user's selection of relevant “exemplary” documents and clusters from this source collection, the system builds a language model of her information need. This model is subsequently used to derive “mediated queries,” which are expected to convey precisely and comprehensively the user's information need, and can be submitted by the user to search any large and heterogeneous “target collections.” We present results of experiments that simulated various mediation strategies and compared the effect on mediation effectiveness of a variety of parameters, such as the similarity measure, the weighting scheme, and the clustering method. They provide both upperbounds of performance that can potentially be reached by real end users and a comparison between the effectiveness of these strategies. The experimental evidence suggests that information retrieval mediated through a clustered specialized collection has potential to improve effectiveness significantly.
Observing users, designing clarity: A case study on the user‐centered design of a cross‐language information retrieval system
Authors: Petrelli Daniela , Beaulieu Micheline , Sanderson Mark , Demetriou George , Herring Patrick , Hansen Preben
Published: April 2004

This report presents a case study of the development of an interface for a novel and complex form of document retrieval: searching for texts written in foreign languages based on native language queries. Although the underlying technology for achieving such a search is relatively well understood, the appropriate interface design is not. A study involving users from the beginning of the design process is described, and it covers initial examination of user needs and tasks, preliminary design and testing of interface components, building, testing, and refining the interface, and, finally, conducting usability tests of the system. Lessons are learned at every stage of the process, leading to a much more informed view of how such an interface should be built.
Bioequivalence evaluation of two brands of aceclofenac 100mg tablets (Aceclofar and Bristaflam) in healthy human volunteers
Authors: Najib Naji , Idkaidek Nasir , Beshtawi M. , Bader Mohammed , Admour Isra' , Alam S. Mahmood , Zaman Q. , Dham Ruwayda
Published: April 2004

A randomized, two‐way, crossover, bioequivalence study in 24 fasting, healthy, male volunteers was conducted to compare two brands of aceclofenac 100mg tablets, Aceclofar (Julphar, UAE) as test and Bristaflam (Bristol Myers Squibb, Egypt) as the reference product. The drug was administered with 240ml of water after a 10h overnight fast on two treatment days separated by 1 week washout period. After dosing, serial blood samples were collected for a period of 24h. Plasma harvested from blood was analysed for aceclofenac by a validated HPLC method with UV‐visible detection capable of detecting aceclofenac in the range 0.2–8.0μg/ml with the limit of quantitation as 0.2μg/ml. Various pharmacokinetic parameters including AUC0−t, AUC0−∞, Cmax, Tmax, T1/2, and λZ were determined from plasma concentrations for both formulations and found to be in good agreement with reported values. AUC0−t, AUC0−∞, and Cmax were tested for bioequivalence after log‐transformation of data. No significant difference was found based on ANOVA; 90% confidence interval (100.0%–106.4% for AUC0−t, 100.2%–106.8% for AUC0−∞; 83.3%–102.8% for Cmax) of test/reference ratio for these parameters were found to be within the bioequivalence acceptance range of 80%–125%. Based on these statistical inferences, it was concluded that Aceclofar is bioequivalent to Bristaflam. Copyright © 2004 John Wiley & Sons, Ltd.
The bioavailability and pharmacokinetics of glucosamine hydrochloride and chondroitin sulfate after oral and intravenous single dose administration in the horse
Authors: Du Jianping , White Nathaniel , Eddington Natalie D.
Published: April 2004

Objective—The purpose of this study was to determine if glucosamine (GL) hydrochloride (FCHG49®) and low molecular weight (LMW) chondroitin sulfate (CS) (TRH122™) are absorbed after oral administration to horses. The bioavailability of LMWCS was evaluated by quantifying the total disaccharides found in the plasma following chondroitinase ABC digestion.

Methods—Two separate studies were conducted. In study 1, ten adult horses received the following four treatments in a randomized crossover fashion: (1) i.v. LMWCS (3 g of 8 kDa), (2) p.o. LMWCS (3 g of 8 kDa), (3) i.v. LMWCS (3 g of 16.9 kDa) and (4) p.o. LMWCS (3 g of 16.9 kDa). Each group received 9 g GL with LMWCS. In a second study, each horse (n=2) was randomly assigned to receive either i.v. administration of GL HCl (9 g) or p.o. administration of GL HCl (125 mg/kg). Blood samples were collected, assayed and pharmacokinetic parameters were determined.

Results—GL was absorbed after oral dosing with a meanCmaxof 10.6 (6.9) μg/ml and a meanTmaxof 2.0 (0.7) h. The extent of absorption of LMWCS after dosing with both the 8.0 and 16.9 kDa provides evidence that LMWCS is absorbed orally.CmaxandAUCwere higher (p<0.05) for the 16.9 kDa material compared with 8.0 kDa. However, the 16.9 kDa bioavailability was less than 8.0 kDa, but this difference was not significant.

Conclusions—This study provides the first report of the bioavailability of orally administered GL and LMWCS in the horse. Copyright © 2004 John Wiley & Sons, Ltd.
Developmental toxicity evaluation of emodin in rats and mice
Authors: Jahnke Gloria D. , Price Catherine J. , Marr Melissa C. , Myers Christina B. , George Julia D.
Published: April 2004

BACKGROUND: Emodin, a widely available herbal remedy, was evaluated for potential effects on pregnancy outcome. METHODS: Emodin was administered in feed to timed‐mated Sprague–Dawley (CD) rats (0, 425, 850, and 1700 ppm; gestational day [GD] 6–20), and Swiss Albino (CD‐1) mice (0, 600, 2500 or 6000 ppm; GD 6–17). Ingested dose was 0, 31, 57, and ∼80–144 mg emodin/kg/day (rats) and 0, 94, 391, and 1005 mg emodin/kg/day (mice). Timed‐mated animals (23–25/group) were monitored for body weight, feed/water consumption, and clinical signs. At termination (rats: GD 20; mice: GD 17), confirmed pregnant dams (21–25/group) were evaluated for clinical signs: body, liver, kidney, and gravid uterine weights, uterine contents, and number of corpora lutea. Fetuses were weighed, sexed, and examined for external, visceral, and skeletal malformations/variations. RESULTS: There were no maternal deaths. In rats, maternal body weight, weight gain during treatment, and corrected weight gain exhibited a decreasing trend. Maternal body weight gain during treatment was significantly reduced at the high dose. In mice, maternal body weight and weight gain was decreased at the high dose. CONCLUSIONS: Prenatal mortality, live litter size, fetal sex ratio, and morphological development were unaffected in both rats and mice. At the high dose, rat average fetal body weight per litter was unaffected, but was significantly reduced in mice. The rat maternal lowest observed adverse effect level (LOAEL) was 1700 ppm; the no observed adverse effect level (NOAEL) was 850 ppm. The rat developmental toxicity NOAEL was ≥1700 ppm. A LOAEL was not established. In mice, the maternal toxicity LOAEL was 6000 ppm and the NOAEL was 2500 ppm. The developmental toxicity LOAEL was 6000 ppm (reduced fetal body weight) and the NOAEL was 2500 ppm. Birth Defects Res B 71:89–101, 2004. © 2004 Wiley‐Liss, Inc.
Protein adsorption at air–water interfaces: A combination of details
Authors: de Jongh Harmen H. J. , Kosters Hans A. , Kudryashova Elena , Meinders Marcel B. J. , Trofimova Daria , Wierenga Peter A.
Published: April 2004

Using a variety of spectroscopic techniques, a number of molecular functionalities have been studied in relation to the adsorption process of proteins to air–water interfaces. While ellipsometry and drop tensiometry are used to derive information on adsorbed amount and exerted surface pressure, external reflection circular dichroism, infrared, and fluorescence spectroscopy provide, next to insight in layer thickness and surface layer concentration, molecular details like structural (un)folding, local mobility, and degree of protonation of carboxylates. It is shown that the exposed hydrophobicity of the protein or chemical reactivity of solvent‐exposed groups may accelerate adsorption, while increased electrostatic repulsion slows down the process. Also aggregate formation enhances the fast development of a surface pressure. A more bulky appearance of proteins lowers the collision intensity in the surface layer, and thereby the surface pressure, while it is shown to be difficult to affect protein interactions within the surface layer on basis of electrostatic interactions. This work illustrates that the adsorption properties of a protein are a combination of molecular details, rather than determined by a single one. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Investigation of the thermal stability of porin from Paracoccus denitrificans by site‐directed mutagenesis and Fourier transform infrared spectroscopy
Authors: Sukumaran S. , Zscherp C. , Mäntele W.
Published: April 2004

The folding of membrane proteins was addressed using outer membrane protein porin from the soil bacterium Paracoccus denitrificans (P. den.). IR spectroscopy and sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS‐PAGE) analysis were used to probe the effect of mutagenesis on the thermal stability of the protein. Secondary structure analysis by amide I ir spectroscopy showed that the wild‐type protein was predominantly composed of β‐sheet, which supports the x‐ray crystal structure information (A. Hirsch, J. Breed, K. Saxena, O.‐M. H. Richter, B. Ludwig, K. Diederichs, and W. Welte, FEBS Letters, 1997, Vol. 404, pp. 208–210). The mutants E81Q, W74C, and E81Q/D148N were shown to have similar secondary structure composition as the wild type. Wild‐type protein and the mutants in detergent micelles underwent irreversible denaturation as a result of heating. Transition temperature calculated from the amide I analysis revealed that mutant porins were slightly less stable compared to the wild type. The protein in micelles showed complete monomerization of the trimer above 85°C. In native‐like conditions (provided by liposomes), no change was observed in the secondary structure of the protein until 95°C. This is supported by SDS‐PAGE as no change in quaternary structure was observed, proving that the proteins are structurally thermostable in liposomes as compared to micelles. Our studies demonstrated that porins resistant to detergents and proteases are highly thermostable as well. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Intracellular uptake of modified oligonucleotide studied by two fluorescence techniques
Authors: Kočišová Eva , Praus Petr , Rosenberg Ivan , Seksek Olivier , Sureau Franck , Štĕpánek Josef , Turpin Pierre‐Yves
Published: April 2004

Interaction, i.e., cellular uptake and intracellular distribution, of synthetic modified antisense oligonucleotide with the B16 melanoma cell line was studied using cationic polyene antibiotic, amphotericin B 3‐dimethylaminopropyl amide, as a carrier vector. The antisense oligonucleotide–dT15 oligomer analogue containing isopolar, nonisosteric, phosphonate‐based internucleotide linkages 3′‐O‐P‐CH2‐O‐5′–was labeled with fluorescent tetramethylrhodamine marker. The oligonucleotide itinerancy across the cell membrane and its distribution inside the cell was visualized using fluorescence microimaging. During the first several hours a strong preference staining of the cell nucleus was found. Fluorescence lifetime measurements from the intracellular environment (confocal laser microspectrofluorimeter, frequency domain phase/modulation technique in 1 to 200 MHz frequency region) yielded two spectral components of 4.9 and 1.4 ns lifetime, respectively. While the former component correlates with the previously characterized effect of the fluorophore binding to biomolecular targets in membranes and/or cytoplasm, the latter component is newly observed and its possible origin is discussed. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Raman study of potential “antisense” drugs: Nonamer oligonucleotide duplexes with a central mismatch as a model system for the binding selectivity evaluation
Authors: Nemecek Daniel , Stepanek Josef , Turpin Pierre‐Yves , Rosenberg Ivan
Published: April 2004

A set of four 9‐mer oligonucleotide duplexes formed between the 5′‐GCATNTCAC‐3′, N=A,C,T,G, and the 5′‐GTGATATGC‐3′ complement has been proposed as a model system for the investigation of novel oligonucleotide analogues (candidates for antisense use) binding selectivity. Raman measurements were carried out on a set of natural DNA 9‐mer in order to verify suitability of the model and to obtain reference spectral data. Difference Raman spectra between the mismatch and match duplexes obtained at 15°C exhibited numerous spectral features sensitively indicating the structural changes. All the three mismatches only very weakly disturb the overall B‐form conformation of the duplex. Significant structural changes that occurred at the mismatch site are reflected mainly by the neighboring thymidine Raman bands at 1377, 1650, and 1675 cm‐1. The intensity change of the two latter bands is almost the same for the T:G and the T:T mismatch while in the case of the T:C mismatch it is just opposite, demonstrating a very different arrangement of the mismatched pair. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Predicting the survival of patients with peritoneal carcinomatosis of colorectal origin treated by aggressive cytoreduction and hyperthermic intraperitoneal chemotherapy
Authors: Verwaal V J , van Tinteren H , van Ruth S , Zoetmulder F A N
Published: April 2004

Background

Peritoneal carcinomatosis in the absence of distant metastasis occurs in approximately 8 per cent of patients with colorectal cancer. Cytoreduction followed by hyperthermic intraperitoneal chemotherapy (HIPEC) is a new treatment option. Patient selection is crucial to outcome.

Methods

Cytoreduction followed by HIPEC was performed in 102 patients with peritoneal carcinomatosis. The following factors were studied for association with survival: perforation and obstruction of the primary lesion, location of the primary lesion, obstruction associated with carcinomatosis, presentation, tumour differentiation and histological type. Extent of disease and completeness of cytoreduction were also studied. Hazard ratios (HRs) were used to study these factors.

Results

Location of the primary tumour in rectum (HR 3·14 (95 per cent confidence interval (c.i.) 1·11 to 8·91); P = 0·069), poor differentiation (HR 1·73 (95 per cent c.i. 1·04 to 2·88); P = 0·031) and signet cell histological type (HR 2·24 (95 per cent c.i. 1·21 to 4·16); P = 0·008) were associated with shorter survival. Important factors predicting survival were the number of affected regions (HR 1·38 (95 per cent c.i. 1·20 to 1·59); P < 0·001), the simplified peritoneal cancer score (HR 1·19 (95 per cent c.i. 1·12 to 1·26); P < 0·001) and completeness of cytoreduction (HR 8·54 (95 per cent c.i. 4·01 to 18·18); P < 0·001). No other factor correlated with survival.

Conclusion

The survival of patients with peritoneal carcinomatosis of colorectal origin is dominated by the extent of disease and the amount of residual tumour after cytoreduction.
Sonnenstrahlung, Hautreaktionen und Sonnenschutz: Chemie am Strand
Authors: Langhals Heinz , Fuchs Kerstin
Published: April 2004

Die chemischen Hintergründe des Sonnenschutzes werden behandelt und wichtige Sonnenschutz‐Substanzen vorgestellt.
Changes in contrast thresholds with mean luminance for chromatic and luminance gratings: A reexamination of the transition from the DeVries–Rose to Weber regions
Authors: Valero Eva M. , Nieves Juan L. , Hernández‐Andrés Javier , García José A.
Published: April 2004

We have examined the influence of the mean luminance level on the detection thresholds for luminance and red–green chromatic gratings for three different spatial frequencies. The changes in detection thresholds according to the mean luminance level reflect the two different regions, the DeVries–Rose and Weber ranges, found in previous studies. The results for luminance gratings suggest that the transition luminance is proportional to the spatial frequency of the grating. Predictions based on the constant‐flux hypothesis indicate, however, that the transition luminance is proportional to the square of the spatial frequency of the grating and so do not describe the distributions of luminance contrast thresholds adequately. For chromatic gratings, we obtained the same transition luminance for the two lowest spatial frequencies, showing that luminance and chromatic mechanisms behave differently as far as the dependence of the transition luminance on spatial frequency is concerned. Our results suggest that the transition luminance is related to the peak spatial frequency of visual mechanisms that respond to luminance and chromatic gratings. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 177–182, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20003