bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on dimensional stability and thermal properties of rubber wood chemically modified with styrene and glycidyl methacrylate
Authors: Devi Rashmi R. , Maji T. K. , Banerjee A. N.
Published: June 2004

Rubber wood (Hevea brasiliensis) was impregnated with styrene and glycidyl methacrylate (GMA) as the crosslinking monomer. After impregnation, the polymerization was accomplished by catalyst heat treatment. Water uptake (%) and water vapor exclusion (%) of the rubber wood were found to be improved on treatment. Dimensional stability expressed in terms of volumetric swelling in water vapor (90% relative humidity) as well as in liquid water and water repellent effectiveness (WRE) of the treated samples were determined and also found to be improved. The wood–polymer interaction was confirmed by FTIR spectroscopy. Thermal properties of untreated and treated wood samples were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetery (DSC) and an improvement in thermal stability was observed for the wood–polymer composites. The improvement in properties observed as more with styrene–GMA (1:1) combination. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1938–1945, 2004
Effects of process conditions and mixing protocols on structure of extruded polypropylene nanocomposites
Authors: Zhu Linjie , Xanthos M.
Published: June 2004

Polymer melt‐direct intercalation or exfoliation is a promising approach for the preparation of nanocomposites. The structure of nanoclay platelets in the nanocomposites depends not only on the properties of polymer matrix and nanoclay, but also on the operating conditions during processing. The objective of the present work is to investigate the effects of clay chemical modifiers, mixing protocols, and operating conditions upon the clay structure in nanocomposites prepared with a corotating twin‐screw extruder. Two mixing methods were used for the nanocomposite preparation: two‐step mixing and one‐step mixing. Experimental results obtained from melt flow index and complex viscosity measurements suggest that nanoclay C15A is more exfoliated than C30B in a polypropylene homopolymer containing a maleic anhydride grafted PP (PB) as compatibilizer. The two‐step mixing method results in better exfoliation for the nanofillers than the one‐step mixing method. A numerical simulation has been carried out to evaluate the mean residence time and shear rate in different screw configurations under various process conditions. X‐ray diffraction experiments indicate that the residence time is a dominant factor in producing satisfactory nanocomposites in extruders. However, high shear rate coupled with long residence time might result in poor exfoliation of clay. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1891–1899, 2004
Effect of temperature on aggregation/dissociation behavior of interpolymer complexes stabilized by hydrogen bonds
Authors: Khutoryanskiy Vitaliy V. , Nurkeeva Zauresh S. , Mun Grigoriy A. , Dubolazov Artem V.
Published: June 2004

The effect of temperature on the aggregation/dissociation behavior of interpolymer complexes based on poly(acrylic acid) and various nonionic polymers—poly(vinyl pyrrolidone), poly(ethylene oxide), poly(acrylamide), hydroxypropylcellulose, hydroxyethylcellulose, poly(vinyl methyl ether), poly(vinyl ether of ethyleneglycol), and vinyl ether of ethyleneglycol‐co‐vinyl butyl ether—has been studied in aqueous solutions. It was shown that nonionic polymers could be classified into two groups according to the stability of their polycomplexes with respect to temperature. The first group of nonionic polymers forms interpolymer complexes, which are stable and undergo further aggregation upon increase in temperature. The second group forms polycomplexes, which dissociate at higher temperatures. The nature of forces stabilizing different interpolymer complexes in aqueous solutions is discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1946–1950, 2004
Sorption equilibrium of Cr(VI) ions by strong base anion exchangers with pyridine structures
Authors: Neagu Violeta , Untea I. , Tudorache Elena , Orbeci Cristina
Published: June 2004

Chromate sorption on pyridine strong base anion exchangers with different functional groups (methyl, ethyl, and butyl groups), at the quaternary nitrogen atoms, was studied as a function of various initial concentrations (100–1500 mg Cr/L) and counterion type. The studied resins in the Cl−[ form have higher Cr(VI)‐retention capacities than those in the SO form. The pyridine strong base anion exchangers showed a selectivity reversal for the sulfate and chromate anions compared to that of the commercial resins. The alkyl substituent length of the quaternary nitrogen atoms exerted a substantial influence on the Cr(VI)‐retention capacity values for the resins in the Cl− form; the chromate anions preferred resins with methyl functional groups, that is, resins with a greater hydrophilic structure. For the resins in the SO form the length of the substituent at the quaternary nitrogen atom had only a negligible influence on their Cr(VI)‐retention values. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1957–1963, 2004
Effect of montmorillonite on the properties of thermosensitive poly(N‐isopropylacrylamide) composite hydrogels
Authors: Bignotti Fabio , Sartore Luciana , Penco Maurizio , Ramorino Giorgio , Peroni Isabella
Published: June 2004

Thermosensitive composite hydrogels containing various amounts of sodium montmorillonite (NaMM) and poly(N‐isopropylacrylamide) (pNIPAAm) were synthesized. Their equilibrium degree of swelling (DS) was measured in NaCl solutions of different ionic strength and at various temperatures. The DS decreased when increasing the clay content and no substantial shift in the phase transition temperature was noticed. The composite hydrogels investigated had a NaMM content ranging between 1.0 and 5.7 wt % (in 0.1M NaCl at 25°C). A considerable enhancement in the response to thermal stimuli was observed for NaMM contents >2–3 wt %. It is suggested that when the NaMM concentration approaches a critical value, the clay platelets can inhibit the formation of the hydrophobic skin layer that hinders shrinking in conventional pNIPAAm hydrogels. The effect of montmorillonite on the mechanical properties of the hydrogels was investigated by uniaxial compression tests, which showed that the modulus increases with the NaMM content. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1964–1971, 2004
Effects of Nigella sativa on oxidative stress and β‐cell damage in streptozotocin‐induced diabetic rats
Authors: Kanter Mehmet , Coskun Omer , Korkmaz Ahmet , Oter Sukru
Published: June 2004

The aim of the present study was to evaluate the possible protective effects of Nigella sativa L. (NS) against β‐cell damage from streptozotocin (STZ)‐induced diabetes in rats. STZ was injected intraperitoneally at a single dose of 50 mg/kg to induce diabetes. NS (0.2 ml/kg/day, i.p.) was injected for 3 days prior to STZ administration, and these injections were continued throughout the 4‐week study. Oxidative stress is believed to play a role in the pathogenesis of diabetes mellitus (DM). To assess changes in the cellular antioxidant defense system, we measured the activities of antioxidant enzymes (such as glutathione peroxidase (GSHPx), superoxide dismutase (SOD), and catalase (CAT)) in pancreatic homogenates. We also measured serum nitric oxide (NO) and erythrocyte and pancreatic tissue malondialdehyde (MDA) levels, a marker of lipid peroxidation, to determine whether there is an imbalance between oxidant and antioxidant status. Pancreatic β‐cells were examined by immunohistochemical methods. STZ induced a significant increase in lipid peroxidation and serum NO concentrations, and decreased antioxidant enzyme activity. NS treatment has been shown to provide a protective effect by decreasing lipid peroxidation and serum NO, and increasing antioxidant enzyme activity. Islet cell degeneration and weak insulin immunohistochemical staining was observed in rats with STZ‐induced diabetes. Increased intensity of staining for insulin, and preservation of β‐cell numbers were apparent in the NS‐treated diabetic rats. These findings suggest that NS treatment exerts a therapeutic protective effect in diabetes by decreasing oxidative stress and preserving pancreatic β‐cell integrity. Consequently, NS may be clinically useful for protecting β‐cells against oxidative stress. © 2004 Wiley‐Liss, Inc.
Improving judgement with prepaid expert advice
Authors: Sniezek Janet A. , Schrah Gunnar E. , Dalal Reeshad S.
Published: June 2004

Decision makers (“Judges”) often make decisions after obtaining advice from an Advisor. The two parties often share a psychological “contract” about what each contributes in expertise to the decision and receives in monetary outcomes from it. In a laboratory experiment, we varied Advisor Experitise and the opportunity for monetary rewards. As expected, these manipulations influenced advice quality, advice taking, and Judge post‐advice decision quality. The main contribution of the study, however, was the manipulation of the timing of monetary rewards (before or after the advising interaction). We found, as predicted, that committing money for expert—but not novice—advice increases Judges' use of advice and their subsequent estimation accuracy. Implications for advice giving and taking are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Factors influencing survival after resection of pulmonary metastases from colorectal cancer
Authors: Vogelsang H , Haas S , Hierholzer C , Berger U , Siewert J R , Präuer H
Published: June 2004

Background

Selection of patients for resection of lung metastases from colorectal cancer is problematic. The aim of this study was to evaluate clinically relevant prognostic factors and to define a subgroup of patients who would most benefit from such surgery.

Patients

Seventy-five patients (median age 58 (range 33–82) years) with pulmonary metastases from colorectal cancer underwent 104 R0 lung resections. Median follow-up was 33 (range 4–116) months. Patients who had no evidence of recurrent extrathoracic disease, no more than three metastases on either side, lobectomy as the maximal surgical procedure, and adequate cardiorespiratory function were eligible for surgery. Univariate and multivariate Cox regression, and classification and regression tree subgroup analyses were performed.

Results

Overall median survival was 33 months, with 3- and 5-year survival rates of 47 and 27 per cent respectively. Size of metastases (relative risk (RR) 2·6) and extent of resection (RR 0·4) were identified as independent prognostic factors. Primary tumour stage was significant in univariate analysis. Subgroup analysis defined two statistically relevant prognostic groups: patients with a maximum metastasis size of 3·75 cm or less with a disease-free interval of more than 10 months and patients with larger metastases and a shorter disease-free interval. Median survival and 5-year survival were 45 months and 39 per cent in the former group, and 24 months and less than 11 per cent in the latter.

Conclusion

Subgroup analysis provided criteria for the selection of patients for R0 resection of lung metastases from colorectal cancer and differentiated between those at high or low risk of early tumour progression; the latter patients would benefit most from surgery.
Prospective assessment of emotional distress, cognitive function, and quality of life in patients with cancer treated with chemotherapy
Authors: Iconomou Gregoris , Mega Vasiliki , Koutras Angelos , Iconomou Alexander V. , Kalofonos Haralabos P.
Published: June 2004

BACKGROUND

The current study sought to delineate prospectively the rates and clinical course of emotional distress, cognitive impairment, and quality of life (QOL) in chemotherapy‐naive patients with cancer and to consider the determinants of global QOL.

METHODS

Patients who consented to participate were administered the European Organization for Research and Treatment of Cancer QLQ‐C30 questionnaire, the Mini‐Mental State Examination (MMSE), and the Hospital Anxiety and Depression Scale before and at the end of treatment (EOT).

RESULTS

Of the 102 patients initially assessed, 80 (78.4%) completed the study. Most aspects of QOL did not change considerably over time. At EOT, patients reported only significant increases in fatigue and significant decreases in sleep disturbance. Although no significant changes emerged in the rates of anxiety or depression throughout chemotherapy, nearly one‐third of the patients experienced severe emotional distress at both points in time. In addition, the authors observed neither significant alteration in the cognitive performance over time nor reliable associations between scores on the MMSE and subjective cognitive function, emotional distress, or QOL. Finally, depression proved to be the leading predictor of global QOL at baseline and at EOT.

CONCLUSIONS

The results indicated that a significant proportion of Greek patients with cancer experienced intense anxiety and depression throughout chemotherapy and confirmed the importance of depression as a strong predictor of global QOL. Routine screening of emotional distress across all phases of cancer is mandatory because it will contribute to the identification of patients who are in need of pharmaceutical and/or psychologic intervention. Cancer 2004. © 2004 American Cancer Society.
Synthesis and Structural Characterization of Novel Oxorhenium(V) Complexes Containing N‐Heterocyclic Carbenes
Authors: Royo Beatriz , Herdtweck Eberhardt , Romão Carlos C.
Published: June 2004

Reaction of [ReOCl3(PPh3)2] with 2 equiv. of 1,3‐diisopropylimidazol‐2‐ylidene (iPr‐carbene) affords [ReOCl3(iPr‐carbene)2] (1). When an excess of free carbene is used, the dicationic species [ReOCl(iPr‐carbene)4][Cl]2 (2) is isolated. The cationic dioxorhenium complex [ReO2(iPr‐carbene)4]+ has been isolated as its I− (3) and ReO4− (4) salts by different reactions. Treatment of [ReO2I(PPh3)2] with an excess of 1,3‐diisopropylimidazol‐2‐ylidene yields compound 3 in quantitative yield. The cationic species is also isolated as an ReO4− salt from the reaction of [ReO2Me(PhCCPh)] with 1,3‐diisopropylimidazol‐2‐ylidene. The molecular structures of [ReOCl3(iPr‐carbene)2] (1) and [ReO2(iPr‐carbene)4][ReO4] (4) have been determined by single‐crystal X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Effective accumulation of poly(vinylpyrrolidone‐co‐vinyl laurate) into the spleen
Authors: Yoshioka Yasuo , Tsutsumi Yasuo , Mukai Yohei , Shibata Hiroko , Okamoto Takayuki , Kaneda Yoshihisa , Tsunoda Shin‐ichi , Kamada Haruhiko , Koizumi Keiichi , Yamamoto Yoko , Mu Yu , Kodaira Hiroshi , Sato‐Kamada Keiko , Nakagawa Shinsaku , Mayumi Tadanori
Published: June 2004

To optimize polymer‐conjugated drugs as a polymeric drug delivery system, it is essential to design polymeric carriers with tissue‐specific targeting capacity. Previously, we showed that polyvinylpyrrolidone (PVP) was the most suitable polymeric carrier for prolonging the blood‐residency of drugs, and was one of the best parent polymers to design the polymeric carriers with targeting capacity. In this study, we synthesized some hydrophobic PVP derivatives, poly(vinylpyrrolidone‐co‐styrene) [poly(VP‐co‐S)] and poly(vinylpyrrolidone‐co‐vinyl laurate) [poly(VP‐co‐VL)], and assessed their biopharmaceutical properties after intravenous administration in mice. The elimination of hydrophobic PVP derivatives from blood was the same as PVP, and the plasma half‐lives of poly(VP‐co‐S) were almost similar to that of poly(VP‐co‐VL). Poly(VP‐co‐VL) efficiently accumulated in the spleen, whereas poly(VP‐co‐S) effectively accumulated in the liver. The level of poly(VP‐co‐VL) in the spleen was about 20 times higher than PVP and poly(VP‐co‐S). These hydrophobic PVP derivatives did not show any cytotoxicity against endothelial cells in vitro. Thus, poly(VP‐co‐VL) may be a useful polymeric carrier for drug delivery to the spleen. This study will provide useful information to design optimal polymeric carriers with targeting capacity to the spleen and liver. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 219–223, 2004
Calcium‐phosphate‐hybridized tendon directly promotes regeneration of tendon‐bone insertion
Authors: Mutsuzaki Hirotaka , Sakane Masataka , Nakajima Hiromi , Ito Atsuo , Hattori Shinya , Miyanaga Yutaka , Ochiai Naoyuki , Tanaka Junzo
Published: June 2004

We developed a novel technique to improve tendon‐bone attachment by hybridizing calcium phosphate (CaP) with tendons using an alternate soaking process. We characterized the deposited CaP on or in tendons and determined the healing process of anterior cruciate ligament (ACL) grafts by implanting CaP‐hybridized free tendons in bone tunnels intra‐articularly. Tendons to be implanted were alternately soaked 10 times in a Ca‐containing solution and a PO4‐containing solution for 30 s each. Treated tendons had ash contents threefold that of untreated tendons. Low‐crystallinity apatite was found on or in treated tendons. In animal experiments, the CaP‐hybridized tendon exhibited osteoclasts at the tendon‐bone interface at 5 days after operation. At 2 weeks after operation, there were more osteoclasts and osteoblasts around the tendon than at 5 days after operation. Directly bonded areas were partially found between the implanted tendon and newly formed bone. The formation of a cartilage layer was partially apparent at 3 weeks after operation. The newly formed bone was observed almost around the tendon. We conclude that CaP‐hybridized tendons clearly enhance the healing process of ACL grafts at the tendon‐bone interface and regenerate a direct insertion‐like formation of tendons similar to a normal healthy ACL insertion within 3 weeks after operation. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 319–327, 2004
Synthesis and evaluation of novel bioactive composite starch/bioactive glass microparticles
Authors: Silva G. A. , Costa F. J. , Coutinho O. P. , Radin S. , Ducheyne P. , Reis R. L.
Published: June 2004

The aim of the development of composite materials is to combine the most desired properties of two or more materials. In this work, the biodegradable character, good controlled‐release properties, and natural origin of starch‐based biomaterials are combined with the bioactive and bone‐bonding properties of bioactive glass (BG). Novel, bioactive composite starch–BG microparticles were synthesized starting from a blend of starch and polylactic acid (50%/50% wt) with BG 45S5 powder using a simple emulsion method. Morphological and chemical characterization showed that these particles exhibited a spherical morphology with sizes up to 350 μm and that BG 45S5 was incorporated successfully into the composite particles. Upon immersion in a solution simulating body fluids, for periods up to 3 weeks, their bioactive nature was confirmed, as a calcium‐phosphate layer resembling biological apatite was formed onto their surface. The short‐term cytotoxicity of these materials was also tested by placing 24‐h leachables of the materials extracted in culture medium in contact with a fibroblastic cell line (L929) up to 72 h. At this time period, two biochemical tests—MTT and total protein quantification—were performed. The results showed that these materials are not cytotoxic. These results constitute the basis of future encapsulation studies using bone‐acting therapeutic agents such as bone morphogenetic proteins or other bone‐relevant factors. The particles developed here may be very useful for applications in which controlled release, degradability, and bone‐bonding ability are the main requirements. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 442–449, 2004
Probing the origins and control of shrinkage stress in dental resin composites. II. Novel method of simultaneous measurement of polymerization shrinkage stress and conversion
Authors: Lu Hui , Stansbury Jeffrey W. , Dickens Sabine H. , Eichmiller Frederick C. , Bowman Christopher N.
Published: June 2004

This study probes the interrelationships between polymerization shrinkage stress development and the polymerization progress with a novel experimental technique. This technique is capable of real time, simultaneous measurement of double‐bond conversion and shrinkage stress with the use of a noninvasive near‐infrared fiber‐optic system, along with a cantilever beam‐based tensometer. The results from both filled and unfilled bis‐GMA/TEGDMA (70:30 mass ratio) systems showed that the shrinkage stress buildup was concentrated in the latter stages of polymerization, with its dramatic increase linked to the asymptotic approach of conversion to its limiting value. The monotonic increase of shrinkage stress with conversion in the vitrified state is attributed to the dramatic increase of the sample's elastic modulus during the vitrification stage and a certain amount of cooling stress as the sample cools down from the temperature rise caused by the exothermic polymerization and light absorption. Excellent reproducibility of both the polymerization kinetics assessment and the shrinkage stress measurement has been achieved. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 206–213, 2004
Rapid, simple, and reliable method for the diagnosis of CAPD peritonitis using the new MMP‐9 test kit
Authors: Ro Yuuki , Hamada Chieko , Io Hiroaki , Hayashi Kayo , Hirahara Ichiro , Tomino Yasuhiko
Published: June 2004

The objective of the present study was to evaluate the sensitivity and efficiency of the matrix metalloproteinase‐9 (MMP‐9) test kit for the diagnosis of bacterial peritonitis in patients undergoing peritoneal dialysis (PD). Peritoneal effluents were collected from seven continuous ambulatory PD (CAPD) patients with peritonitis, four patients with suspected peritonitis, 30 maintenance PD patients without infection, and seven patients at initiation of PD. The MMP‐9 test kit was used to analyze 112 peritoneal effluent samples. These peritoneal effluents were also used to count leukocytes and examine microorganisms. MMP expression was measured by gelatin zymography, and activities were measured by an enzyme‐linked immunosorbent assay (ELISA). The relationship between the reactivity of the test kit and the number of leukocytes in the samples was examined. There was a significant difference in the number of leukocytes in peritoneal effluents between the negative and positive groups detected by the MMP‐9 test kit (P<0.0001). The results obtained with the MMP‐9 test kit were negative for peritoneal effluent samples that did not show increased cell counts. The reactivity of the MMP‐9 test kit showed no significant differences among various microorganisms, and remained stable. The MMP‐9 test kit appears to be a simple and reliable method for early diagnosis of CAPD peritonitis, and reflects the leukocyte count in peritoneal effluents. J. Clin. Lab. Anal. 18:224–230, 2004. © 2004 Wiley‐Liss, Inc.
Effects of apolipoprotein E on the human immunodeficiency virus protein tat in neuronal cultures and synaptosomes
Authors: Pocernich Chava B. , Sultana Rukhsana , Hone Eugene , Turchan Jadwiga , Martins Ralph N. , Calabrese Vittorio , Nath Avindra , Butterfield D. Allan
Published: June 2004

Human immunodeficiency virus type 1 (HIV‐1)‐associated dementia is observed in 20–30% of patients with acquired immunodeficiency syndrome (AIDS). The ϵ4 allele of the apolipoprotein E (APOE) gene currently is thought to play a role as a risk factor for the development of HIV dementia. The HIV protein Tat is neurotoxic and binds to the same receptor as apoE, the low‐density lipoprotein receptor‐related protein (LRP). In this study, we investigated the role apoE plays in Tat toxicity. Synaptosomes from wild‐type mice treated with Tat had increased reactive oxygen species (ROS), increased lipid and protein oxidation, and decreased mitochondrial membrane potential. Synaptosomes from APOE‐knockout mice also had increased ROS, increased protein oxidation, and decreased mitochondrial membrane potential, but to a significantly lesser degree. Treatment of synaptosomes with heparinase and Tat increased Tat‐induced oxidative stress, consistent with the notion of Tat requiring interaction with neuronal membranes to induce oxidative damage. Human lipidated apoE3 greatly protected neurons from Tat‐induced toxicity, whereas human lipidated apoE4 showed no protection. We demonstrated that human apoE3 has antioxidant properties against Tat‐induced toxicity. Taken together, the data suggest that murine apoE and human apoE4 act similarly and do not protect the cell from Tat‐induced toxicity. This would allow excess Tat to remain outside the cell and interact with synaptosomal membranes, leading to oxidative stress and neurotoxicity, which could contribute to dementia associated with HIV. We show that the antioxidant properties of apoE3 greatly outweigh the competition for clearance in deterring Tat‐induced oxidative stress. © 2004 Wiley‐Liss, Inc.
Spinal myoclonus responsive to topiramate
Authors: Siniscalchi Antonio , Mancuso Franco , Russo Emilio , Ibbadu Guido Ferreri , De Sarro Giovambattista
Published: June 2004

Spinal segmental myoclonus rarely occurs in peripheral neurological disorders. There are no data about the efficacy of topiramate (TPM) on spinal myoclonus. We describe a patient whose segmental myoclonus in amputation stump was ameliorated markedly by TPM. © 2004 Movement Disorder Society
A constraint‐stabilized time‐stepping approach for rigid multibody dynamics with joints, contact and friction
Authors: Anitescu Mihai , Hart Gary D.
Published: June 2004

We present a method for achieving geometrical constraint stabilization for a linear‐complementarity‐based time‐stepping scheme for rigid multibody dynamics with joints, contact, and friction. The method requires the solution of only one linear complementarity problem per step. We prove that the velocity stays bounded and that the constraint infeasibility is uniformly bounded in terms of the size of the time step and the current value of the velocity. Several examples, including one for joint‐only systems, are used to demonstrate the constraint stabilization effect. Copyright © 2004 John Wiley & Sons, Ltd.
Personality and social network effects on romantic relationships: a dyadic approach
Authors: Neyer Franz J. , Voigt Daniel
Published: June 2004

The quality of romantic relationships and their associations with both partners' personality traits and social networks were studied in 100 younger couples. The similarity of partners was modest with respect to personality traits, and moderate to large with respect to the perceived quality of the partner relationship and their social networks. While similarity in personality was unrelated to relationship quality, dyadic analyses showed that one's perceived quality of relationship was better predicted by one's own personality (i.e. actor effects) than by the personality of one's partner (i.e. partner effects). Moreover, relationship quality could to some extent be predicted by the quality of the social network once the personality traits of each partner were controlled. Results are discussed from a transactional view of personality and relationships. Copyright © 2004 John Wiley & Sons, Ltd.
The Big Five related to risky sexual behaviour across 10 world regions: differential personality associations of sexual promiscuity and relationship infidelity
Authors: Schmitt David P.
Published: June 2004

As part of the International Sexuality Description Project, 16 362 participants from 52 nations responded to measures of the Big Five and ‘risky’ sexuality. It was expected that low levels of agreeableness and conscientiousness would be universally associated with relationship infidelity. Sexual promiscuity, in contrast, was expected to positively relate to extraversion and neuroticism. Analyses across 10 world regions revealed relationship infidelity was universally associated with low agreeableness and low conscientiousness. Sexual promiscuity was somewhat related to these traits as well, but was more highly related to extraversion across many, but not all, world regions. Both forms of risky sexual behaviour were generally unrelated to neuroticism and openness across cultures. Discussion focuses on possible explanations of regional differences in personality–sexuality linkages. Copyright © 2004 John Wiley & Sons, Ltd.
Computational, spectroscopic, and resonant mirror biosensor analysis of the interaction of adrenodoxin with native and tryptophan‐modified NADPH‐adrenodoxin reductase
Authors: Sargisova Yelizaveta , Pierfederici Francesco‐Maria , Scirè Andrea , Bertoli Enrico , Tanfani Fabio , Febbraio Ferdinando , Briante Raffaella , Karapetyan Yelena , Mardanyan Sona
Published: June 2004

In steroid hydroxylation system in adrenal cortex mitochondria, NADPH‐adrenodoxin reductase (AR) and adrenodoxin (Adx) form a short electron‐transport chain that transfers electrons from NADPH to cytochromes P‐450 through FAD in AR and [2Fe‐2S] cluster in Adx. The formation of [AR/Adx] complex is essential for the electron transfer mechanism in which previous studies suggested that AR tryptophan (Trp) residue(s) might be implicated. In this study, we modified AR Trps by N‐bromosuccinimide (NBS) and studied AR binding to Adx by a resonant mirror biosensor. Chemical modification of tryptophans caused inhibition of electron transport. The modified protein (AR*) retained the native secondary structure but showed a lower affinity towards Adx with respect to AR. Activity measurements and fluorescence data indicated that one Trp residue of AR may be involved in the electron transferring activity of the protein. Computational analysis of AR and [AR/Adx] complex structures suggested that Trp193 and Trp420 are the residues with the highest probability to undergo NBS‐modification. In particular, the modification of Trp420 hampers the correct reorientation of AR* molecule necessary to form the native [AR/Adx] complex that is catalytically essential for electron transfer from FAD in AR to [2Fe‐2S] cluster in Adx. The data support an incorrect assembly of [AR*/Adx] complex as the cause of electron transport inhibition. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Selective digestion and novel cleanup techniques for detection of benzo[a]pyrene diol epoxide‐DNA adducts by capillary electrophoresis/mass spectrometry
Authors: Gennaro Lynn A. , Vadhanam Manicka , Gupta Ramesh C. , Vouros Paul
Published: June 2004

Benzo[a]pyrene (BP) is a ubiquitous environmental polycyclic aromatic hydrocarbon (PAH) which, upon metabolic conversion to reactive benzo[a]pyrene‐7,8‐diol‐9,10‐epoxide (BPDE), has been found to attach covalently to DNA. Given the low level of DNA adducts typically present in vivo or in vitro, an essential first step prior to capillary electrophoresis/mass spectrometry (CE/MS) (or liquid chromatography/mass spectrometry (LC/MS)) analysis of the DNA digests is the removal of the bulk non‐adducted nucleotides, enzymes or salts, and isolation of enriched adducts. This report focuses on the development of novel sample handling methods aimed at facilitating the analysis of BPDE‐DNA adducts by CE/MS. This approach involves a simple variation on the digestion procedure, in combination with the use of metal affinity ZipTips for the more efficient cleanup of BPDE‐DNA adducts formed in vitro for subsequent CE/MS analysis. The previously described digestion procedure, consisting of micrococcal nuclease, spleen phosphodiesterase and nuclease P1, allows for selective dephosphorylation of normal nucleotides, while leaving adducted nucleotides intact. Metal affinity ZipTips, typically used for selective extraction of phosphopeptides, were used here for extraction of adducted nucleotides. The utility of metal affinity SPE was tested on mixtures of dG and dGp, wherein nucleotide extracts contained no detectable nucleosides by CE/UV analysis. An in vitro BPDE‐DNA incubation was then digested using the above procedure. Metal affinity solid‐phase extraction (SPE) was subsequently used for the selective isolation of phosphorylated components, i.e., adducted nucleotides, from the mixture of enzymes and non‐adducted nucleosides. SPE extracts were enriched in nucleotide adducts and analyzed using sample stacking and CE/MS. This method has several advantages over previously described cleanup procedures for dGp‐BPDE adducts: fast, simple, uses commercially available materials, no need for excessive dilution (small scale), the suitability for use with automation, and possible applicability to other bulky hydrophobic adducts. Copyright © 2004 John Wiley & Sons, Ltd.
Six years follow‐up of an implanted SvO2 sensor in the right ventricle
Authors: Kjellström Barbro , Linde Cecilia , Bennett Tom , Ohlsson Åke , Ryden Lars
Published: June 2004

Introduction.

Mixed venous oxygen saturation (SvO2) is a standard invasive measure used in the management of congestive heart failure patients. The reliability of a long‐term SvO2 sensor remains unproven.

Methods.

Nine patients (NYHA Class I/II, n=2/7) were implanted with a dual chamber pacemaker modified to utilize a right ventricular SvO2 lead (Medtronic Inc., Models 8007/4327A IPG/Lead). Invasive studies compared sensor SvO2 to reference (Optical Swan–Ganz catheter) at 0, 3 and 9 months. Symptom limited tests (Bikemax) with metabolic assessment and arterial oxygen saturation measurements performed 1–7 days, 3.5 and 9.5 months post‐implant allowed for cardiac output calculations. Long‐term sensor performance was confirmed by submaximal tests, Bikesubm in years 1–3, and Walkin‐place every 6 months for the duration of follow‐up.

Results.

Sensor SvO2 readings were stable over time when compared to the Swan–Ganz Catheter. Non‐invasive CO measured during Bikemax was in normal ranges for this patient population, 3.7±0.9 l/min at rest and 8.4±2.2 l/min at peak‐exercise. Resting SvO2 values from Bikesubm and Walkin‐place did not change significantly over time (P0.1 vs. 1 year) and neither did the change from rest to peak exercise during Bikesubm (P0.05 vs. 1 year) or Walkin‐place (P0.05 vs. 4 year).

Conclusion.

While limited in size, this small pilot study suggests that long‐term monitoring of SvO2 by implanted devices may be feasible. The clinical value remains to be proven in future studies.
Fishing vs. natural recruitment variation in sandeels as a cause of seabird breeding failure at Shetland: a modelling approach
Authors: Poloczanska Elvira S. , Cook Robin M. , Ruxton Graeme D. , Wright Peter J.
Published: June 2004

Sandeels represent a major component in the diet of fish, bird, and mammal predators as well as supporting a large industrial fishery. The availability of young sandeels in coastal waters around Shetland is generally considered a key factor influencing the breeding success of many seabird species in the area, but the risk to the populations as a direct consequence of the fishery is unknown. Low exploitation rates coupled with high natural mortality rates make assessment of the Shetland sandeel stock problematic and safe biological limits have not yet been defined. We use stochastic models to evaluate the likely effect of varying fishing mortality on kittiwake breeding success. The models consider some main sources of uncertainty about natural processes, such as recruitment and natural mortality, which may affect the design of robust management strategies. The type of model tested had a stronger influence on sandeel recruitment than the level of fishing pressure. Even with low exploitation rates, poor years for seabird breeding were inevitable.
C‐Met Overexpression in Supraglottic Laryngeal Squamous Cell Carcinoma and its Relation to Lymph Node Metastases
Authors: Taskin Yücel Ö , Sungur Arzu , Kaya Sefa
Published: June 2004

BACKGROUND

The c‐met oncogene encodes the receptor for the hepatocyte growth factor/scatter factor (HGF/SF), which is known to have the effects of stimulation of cell motility, dissociation of epithelial sheets, invasion of cellular matrix, and induction of angiogenesis. Many studies in solid tumors have indicated a role for c‐met and HGF/SF in the progression of the disease.

METHODS

The expression of c‐met in tissue specimens was studied by immunohistochemical examination in 60 patients with supraglottic laryngeal squamous cell carcinoma. Patients were chosen such that there were 30 with lymph node metastases in the neck and 30 without metastases. TNM staging, differentiation, lymphovascular and perineural invasion, and growth pattern for tumors were also recorded, and their relation to lymph node metastases was analyzed.

RESULTS

Overexpression of c‐met was observed in 90% of the cases at the primary site and in 83% of the cases with lymph node metastases in the neck. Lymphovascular invasion (P = 0.005) and the N stage (P = 0.001) were found to be related to lymph node metastases, but other variables—c‐met over‐expression, the T stage, perineural invasion, and growth pattern—were found to have no relation to lymph node metastases in multivariate analysis of the data with linear regression.

CONCLUSIONS

c‐met overexpression is observed in both the primary site and the neck in supraglottic laryngeal squamous cell carcinoma. We believe that it may have a role in the progression of malignancy, but we were unable to find a definite relation between c‐met expression and lymph node metastases. (Otolaryngol Head Neck Surg 2004;130:698‐703.)
Tone Perception of Cantonese‐Speaking Prelingually Hearing‐Impaired Children with Cochlear Implants
Authors: Wong Angela O. C. , Wong Lena L. N.
Published: June 2004

OBJECTIVE: To evaluate tone perception performance in Cantonese‐speaking prelingually hearing‐impaired children with cochlear implants.

STUDY DESIGN AND SETTING: The ability to discriminate and identify Cantonese tones was evaluated on 17 native Cantonese‐speaking prelingually hearing‐impaired children. Performance was correlated to factors like age of implantation and general communication ability.

RESULTS: Subjects' performance in discrimination and identification tasks was slightly above chance level. Although variations in the contour fundamental frequency of the tones provided some cues for tone discrimination, these distinctions proved insufficient for subjects to perform well. Tone 6 (low level tone) was the most difficult to identify. Subjects' performance did not correlate with gender, age of implantation, duration of implant use, frequency of auditory training session, or general communication ability.

CONCLUSION: Although some children were able to discriminate and/or identify Cantonese tones, their performance was poor. Further studies are needed to understand how tone perception relate to daily speech understanding.

SIGNIFICANCE: Cochlear implant speech coding strategies may need modification to optimize tone perception. (Otolaryngol Head Neck Surg 2004; 130:751‐8.)
Tuberculous Otitis Media: A Significant Diagnostic Challenge
Authors: Vaamonde Pedro , Castro Crisanto , García‐Soto Nicolas , Labella Torcuato , Lozano Ascension
Published: June 2004

OBJECTIVE

This study was undertaken to revise the diagnostic characteristics of tuberculous otitis media (TOM), a disorder that is often diagnosed late, leading to delay in specific treatment.

STUDY DESIGN AND SETTING

Retrospective study of a longitudinal series of 10 TOM patients over a 7‐year period at an institutional referral center.

RESULTS

Most patients showed intractable otorrhea, moderately severe hearing loss, and necrotic eardrums with granulation tissue and single perforations. Multiple perforations, facial palsy, and cervical adenopathies were rare (<10% of patients). CT generally showed soft tissue involvement of the middle ear without bone erosion. The most effective laboratory test microbiological culture of exudate (diagnostic efficacy 71%). Specific antibiotic treatment was effective in all cases.

CONCLUSION

The diagnosis of TOM remains a significant challenge for otorhinolaryngologists.

SIGNIFICANCE: If there are strong clinical grounds for suspicion, standard laboratory tests for tuberculosis should be repeated even if initially negative. (Otolaryngol Head Neck Surg 2004;130:759‐66.)
Editorial
Authors: Miskin Christine
Published: June 2004

As discussions over the price increases levied by LexisNexis (formerly Butterworths – I suppose we will eventually get used to the new branding and stop pining for our old friend!) on certain of their electronic products continues, it is perhaps fitting that our leading article in this issue is a comparihson of the online services offered by LexisNexis and Westlaw UK. Paul Norman is particularly well-suited to writing it, as he has many years experience of using and teaching both services within the academic environment, from which perspective his article is written. He has comprehensively covered all aspects of the services from coverage, through searching and documentation, to customer support. His article also ties in nicely with the imminent launch of the Online Register of Electronic Resources by the Association.
BIALL Legal Serials Award 2003 – Serial Publication of the Year
Authors: Miskin Christine
Published: June 2004

The journal PLC was a worthy winner of the BIALL Serials Award for 2003. PLC, which has been regularly nominated for the award by BIALL members, was in competition with almost a dozen other journals. The adjudication panel agreed that PLC is a journal which has attained excellence in quality, innovation and originality, especially in its presentation of information, as a print journal. It has also successfully meshed print with online to produce a truly new era product.
Preferred reversal paths caused by a heterogeneous conducting layer at the base of the mantle
Authors: Costin Simona O. , Buffett Bruce A.
Published: June 2004

Time variations in the geomagnetic field induce secondary electric currents in the mantle, which contribute to the magnetic field at the surface. We explore the possibility that currents in a conducting layer at the base of the mantle disturb the transition field during magnetic reversals and alter the path of the virtual geomagnetic pole (VGP). We calculate the magnitude of the magnetic perturbation during a reversal and quantify the influence of this perturbation on the VGP reversal path. The calculations show that the VGP reversal path depends on the geographic position of the observation site. A histogram of reversal paths obtained using a randomly distributed set of sites reveals a preferred path through the Americas. When the histogram of reversal paths is evaluated with a limited number of sites, based on locations in existing lava and sediment databases, we find that the paths are confined to Asian and American longitudes, which is compatible with reversal path distributions inferred from paleomagnetic records.
Temperatures, polar mesosphere summer echoes, and noctilucent clouds over Spitsbergen (78°N)
Authors: Lübken Franz‐Josef , Zecha Marius , Höffner Josef , Röttger Jürgen
Published: June 2004

Simultaneous measurements of temperatures, polar mesosphere summer echoes (PMSE), and noctilucent clouds (NLC) took place in the polar cap (78°N) during the Rocketborne Observations in the Middle Atmosphere campaign (ROMA) in summer 2001. PMSE were observed practically permanently from the beginning and prior to the ROMA campaign (mid‐July) until mid‐August and disappeared by the end of August. PMSE occur between 81 and 92 km but have maximum occurrence rates between 83 and 89 km (up to 80% per day). PMSE are compared with temperatures from falling spheres, with frost point temperatures (Tf), and with degrees of saturation (S) using water vapor mixing ratios from models. PMSE occur nearly exclusively at altitudes with supersaturation, but the reverse is not true. Temperatures within PMSE layers can be up to 20–25 K below Tf. There is no correlation between the radar echo power and the magnitude of S. Around the mesopause we frequently find S values significantly larger than 1 (up to 13000) at altitudes with the confirmed absence of PMSE. This could indicate that the actual water vapor mixing ratio is substantially smaller than our assumed model values in line with the “freeze‐drying effect.” The mean of all NLC peak altitudes is 83.6 km (variability: ±1.1 km), and the occurrence rate is 77% in the main summer season. Most of the time the lower edges of PMSE and NLC are colocated within a few hundred meters or less, which can be explained by a rapid evaporation of ice particles. This close agreement also indicates a rather homogeneous horizontal distribution of ice particles at scales below a few kilometers. The seasonal and height variation of PMSE nicely agrees with the time/height range of S > 1 and confirms the overwhelming importance of low enough temperatures for the existence of PMSE. The variation of NLC also agrees with the seasonal variation of S but covers only the lower height range with supersaturation in line with the different sensitivity of NLC and PMSE on particle radius. From the combined observations of PMSE and NLC, mean occurrence rates of neutral air turbulence of larger than ∼50% are deduced. The experimental results at Spitsbergen confirm the standard scenario of PMSE and NLC, namely that particles start to nucleate around the mesopause, and grow and sediment until they reach “warm” atmospheric regions around 82 km where they quickly evaporate. Small ice particles can affect the plasma leading to PMSE, whereas they need to grow to radii larger than approximately 20 nm to be seen by lidar.
Export fluxes of calcite in the eastern equatorial Pacific from the Last Glacial Maximum to present
Authors: Loubere Paul , Mekik Figen , Francois Roger , Pichat Sylvain
Published: June 2004

The eastern equatorial Pacific (EEP) is an important center of biological productivity, generating significant organic carbon and calcite fluxes to the deep ocean. We reconstructed paleocalcite flux for the past 30,000 years in four cores collected beneath the equatorial upwelling and the South Equatorial Current (SEC) by measuring ex230Th‐normalized calcite accumulation rates corrected for dissolution with a newly developed proxy for “fraction of calcite preserved.” This method produced very similar results at the four sites and revealed that the export flux of calcite was 30–50% lower during the LGM compared to the Holocene. The internal consistency of these results supports our interpretation, which is also in agreement with emerging data indicating lower glacial productivity in the EEP, possibly as a result of lower nutrient supply from the southern ocean via the Equatorial Undercurrent. However, these findings contradict previous interpretations based on mass accumulation rates (MAR) of biogenic material in the sediment of the EEP, which have been taken as reflecting higher glacial productivity due to stronger wind‐driven upwelling.
Time‐variable gravity from GRACE: First results
Authors: Wahr John , Swenson Sean , Zlotnicki Victor , Velicogna Isabella
Published: June 2004

Eleven monthly GRACE gravity field solutions are now available for analyses. We show those fields can be used to recover monthly changes in water storage, both on land and in the ocean, to accuracies of 1.5 cm of water thickness when smoothed over 1000 km. The amplitude of the annually varying signal can be determined to 1.0 cm. Results are 30% better for a 1500 km smoothing radius, and 40% worse for a 750 km radius. We estimate the annually varying component of water storage for three large drainage basins (the Mississippi, the Amazon, and a region draining into the Bay of Bengal), to accuracies of 1.0–1.5 cm.