bluuebunny/crossref_metadata_2025 huggingface dataset:
Curing behavior study of polydimethylsiloxane‐modified allylated novolac/4,4′‐bismaleimidodiphenylmethane resin
Authors: Li Wanwan , Liu Feng , Wei Liuhe , Zhao Tong
Published: September 2007

The curing behavior of polydimethylsiloxane‐modified allylated novolac/4,4′‐bismaleimidodiphenylmethane resin (PDMS‐modified AN/BDM) was investigated by using Fourier transform infrared spectrometry (FTIR) and differential scanning calorimetry. The results of FTIR confirmed that the curing reactions of the PDMS‐modified AN/BDM resins, including “Ene” reaction and Diels–Alder reaction between allyl groups and maleimide groups, should be similar to those of the parent allylated novolac/4,4′‐bismaleimidodiphenylmethane (AN/BDM) resin. The results of dynamic DSC showed that the total curing enthalpy of the PDMS‐modified AN/BDM resins was lower than that of the parent resin. Incorporation of polydimethylsiloxane (PDMS) into the backbone of the allylated novolac (AN) resin favored the Claisen rearrangement reaction of allyl groups. The isothermal DSC method was used to study the kinetics of the curing process. The experimental data for the parent AN/BDM resin and the PDMS‐modified AN/BDM resins exhibited an nth‐order behavior. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Ethylenediamino bridged bis(β‐cyclodextrin)/ poly(DL‐lactic‐co‐glycolic acid) nanoparticles prepared by modified double emulsion method: Effect of polyvinyl alcohol on nanoparticle properties
Authors: Gao Hui , Wang Yinong , Fan Yunge , Ma Jianbiao
Published: September 2007

This study continues long‐standing efforts to develop protein delivery systems based on cyclodextrin‐conjugated polyester in our laboratory. The crude products of ethylenediamino bridged bis(β‐cyclodextrin)‐conjugated poly(DL‐lactic‐co‐glycolic acid) were used in this study to make full use of unreacted reactant. With bovine serum albumin (BSA) as a model protein, the encapsulation effects (the encapsulation efficiency and particle size) of nanoparticles were similar to those of using pure conjugated products. Besides, a water‐in‐oil‐in‐water emulsification technique was conveniently modified. By adding polyvinyl alcohol (PVA) in the internal aqueous phase, a more stabilized emulsion was formed. Consequently, less PVA (∼ 0.05%) was needed in the outer aqueous phase and less PVA (0.14 g/g nanoparticles) remained in the nanoparticles. This modification resulted in improved encapsulation efficiency (∼ 89–94%) of BSA and an enlarged particle size (340–390 nm). Furthermore, the burst release of BSA at the 1st day was less pronounced (7–12% of the encapsulated amount) than that of nanoparticles with no PVA added in the internal aqueous phase. Degradation studies using transmission electron microscope and gel permeation chromatography suggested that the mechanism for protein release was mainly through nanoparticles erosion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of water on the nanoindentation creep response of nylon 6
Authors: Bell Gerard A. , Bieliński Dariusz M. , Beake Ben D.
Published: September 2007

A nanoindentation system fitted with a fluid cell has been used to probe the influence of water on the nanoindentation creep response of commercial Nylon‐6 samples. Measurements on samples taken while immersed in deionized water were compared with measurements under usual ambient (∼ 50% relative humidity) conditions. Water absorption reduces hardness by around 50% and elastic modulus by around 65%. The dimensionless creep parameter, A/d(0), where A is a constant and d(0) is the initial penetration at the start of the creep‐hold period, is a measure of the proportion of time‐dependent deformation compared with the total deformation. This parameter decreases significantly in water. We have suggested previously that A/d(0) correlates with tan δ. The observed reduction in A/d(0) when wet is consistent with a decrease in the tan δ peak due to a shift in the glass transition temperature when wet. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Crystallization of poly(butylene terephthalate)/poly(ethylene octene) blends: Nonisothermal crystallization
Authors: Huang Jiann‐Wen , Wen Ya‐Lan , Kang Chiun‐Chia , Yeh Mou‐Yung , Wen Shaw‐Bing
Published: September 2007

Poly(ethylene octene) (POE), maleic anhydride grafted poly(ethylene octene) (mPOE), and a mixture of POE and mPOE were added to poly(butylene terephthalate) (PBT) to prepare PBT/POE (20 wt % POE), PBT/mPOE (20 wt % mPOE), and PBT/mPOE/POE (10 wt % mPOE and 10 wt % POE) blends with an extruder. The melting behavior of neat PBT and its blends nonisothermally crystallized from the melt was investigated with differential scanning calorimetry (DSC). Subsequent DSC scans exhibited two melting endotherms (TmI and TmII). TmI was attributed to the melting of the crystals grown by normal primary crystallization, and TmII was due to the melting of the more perfect crystals after reorganization during the DSC heating scan. The better dispersed second phases and higher cooling rate made the crystals that grew in normal primary crystallization less perfect and relatively prone to be organized during the DSC scan. The effects of POE and mPOE on the nonisothermal crystallization process were delineated by kinetic models. The dispersed phase hindered the crystallization; however, the well‐ dispersed phases of an even smaller size enhanced crystallization because of the higher nucleation density. The nucleation parameter, estimated from the modified Lauritzen–Hoffman equation, showed the same results. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Crystallization and melting behavior of the crystalline soft segment in a shape‐memory polyurethane ionomer
Authors: Zhu Yong , Hu Jinlian , Choi Ka‐Fai , Yeung Kwok‐Wing , Meng Qinghao , Chen Shaojun
Published: September 2007

To illustrate the crystallization properties of soft segments in shape‐memory polyurethane (SMPU) ionomers, a series of SMPU ionomers with various ionic group contents and two kinds of counterions were synthesized with a prepolymerization method. An isothermal crystallization kinetic method was used to analyze the effects of ionic groups within the hard segments on the crystallization of the soft segments in a heating and cooling routine similar to that in a shape‐memory function. The more ionic groups there were within the hard segments, the lower the crystallization rate was of the soft segments. The crystallization mechanism of the SMPU ionomers was quite close to that of a control sample on the basis of similar Avrami exponents; the counterion category also had some influence on the crystallization rate. Meanwhile, the melting behavior after isothermal crystallization reflected the fact that the thermal history of the hard segments had a huge effect on the crystallization mechanism of the soft segments. Especially for the SMPU ionomer quenched from 240°C, the crystallization time dependence of the secondary crystallization was rather significant, but for the SMPU ionomer quenched from 70°C, the primary crystallization of the poly(ϵ‐caprolactone) soft segment was predominant. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of coupling agents on the natural aging behavior and oxidation profile of high‐density polyethylene/sericite composites
Authors: Yang Rui , Yu Jian , Liu Ying , Wang Kunhua
Published: September 2007

The natural photooxidation of high‐density polyethylene (HDPE)/sericite composites was carried out outdoors for 180 days. The oxidative products, oxidation profile, and section morphology were characterized with Fourier transform infrared spectroscopy, infrared microscopy, and scanning electron microscopy, respectively. The results showed that HDPE/sericite had a higher oxidation degree than HDPE. All the coupling agents (CAs) accelerated the oxidation reaction of HDPE and made the final carbonyl index higher than that of an untreated one. The effect of sericite might have been due to the increased ultraviolet absorbance, whereas the effects of CAs might have been due to the active functional groups. Furthermore, cracks in the sections of test bars of HDPE/sericite composites after natural exposure were also observed. Their average lengths and densities were different for various CA treatments. This difference had a direct correspondence with the oxidation profile along the depth. This demonstrated that significant oxidation and consequently chain scission in the surface layer were responsible for the formation of cracks. Comparing the natural aging behavior of the films with test bars, we obtained more information about the propagation of the photooxidation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of colophony emulsion on the adhesive properties of vinyl acetate/n‐butyl acrylate copolymeric latex
Authors: Zhu Ai‐Ping , Chen Rui , Yuan Lan‐Hua
Published: September 2007

We prepared a novel copolymeric latex of vinyl acetate and n‐butyl acrylate (V‐B) using a semibatch emulsion polymerization process. The glass‐transition temperature (Tg), steady viscosity, flow activation energy (Ef), dynamic moduli, and amphiphilic properties of the V‐B latex in the presence of colophony were systematically investigated. The experimental results demonstrate that excellent adhesive behaviors were achieved for the V‐B latex blended with 20 wt % colophony, whereas good adhesive performance was related to the moderate Tg, viscosity, Ef, storage modulus, and low contact angle on the adherent. The debonding mechanisms for V‐B and its colophony‐modified latexes were analyzed. A possible mechanism for the V‐B latex blended with colophony emulsion was determined. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Comparison of the structures and properties of Lyocell fibers from high hemicellulose pulp and high α‐cellulose pulp
Authors: Zhang Huiru , Zhang Huihui , Tong Mingwei , Shao Huili , Hu Xuechao
Published: September 2007

Lyocell fibers were produced from a cheap pulp with a high hemicellulose content and from a conventional pulp with a high α‐cellulose content. The mechanical properties, supermolecular structure, fibrillation resistance, and dyeing properties as well as the fibril aggregation size of the high hemicellulose Lyocell fiber and high α‐cellulose Lyocell fiber were compared. The results showed that the high hemicellulose spinning solution could be processed at a higher concentration, which improved the mechanical properties and the efficiency of the fiber process. Compared with the high α‐cellulose Lyocell fiber, the high hemicellulose Lyocell fiber had better fibrillation resistance and dyeing properties. Therefore, it is feasible that this cheap pulp with a high hemicellulose content can be used as a raw material for producing Lyocell fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Intercalation process and rubber–filler interactions of polybutadiene rubber/organoclay nanocomposites
Authors: Wan Chaoying , Dong Wei , Zhang Yinxi , Zhang Yong
Published: September 2007

The intercalation process and microstructural development of polybutadiene rubber (BR)/clay nanocomposites cured with sulfur were systematically investigated with respect to the organic modifier (primary and quaternary ammonium compounds) of the clay. X‐ray diffraction spectra were recorded at various stages of processing to obtain information about the intercalation process. The rubber–filler interactions was examined on the basis of the surface free energy, stress‐softening effect, and crystallization behavior. A well‐ordered intercalated structure was obtained in the primary ammonium modified clay (P‐OMMT) and quaternary ammonium modified clay (Q‐OMMT) filled with BR composite. The BR/Q‐OMMT composites showed higher mechanical properties and higher hysteresis under tension and lower crystallization abilities than the BR/P‐OMMT composites. The results also show that higher interfacial interactions existed between Q‐OMMT and BR than between P‐OMMT and BR. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Tensile behavior of glass‐fiber‐filled polyacetal: Influence of the functional groups of polymer matrices
Authors: Kawaguchi Kuniaki , Masuda Eiji , Tajima Yoshihisa
Published: September 2007

We investigated the tensile behavior of glass‐fiber‐filled polyacetal [i.e., polyoxymethylene (POM)], focusing on the mutual influence of the functional groups in the POM matrices and the glass binder system. The different POM matrices were compounded with three kinds of glass fibers (20 wt %) treated with different glass binders, namely, epoxy resin, thermoplastic polyurethane (TPU), and a mixture of TPU and epoxy resin. A good correlation between the tensile strength and elongation at break was observed, regardless of the difference in the glass binders. The composites based on the modified POM matrix, which had both a carboxyl end group and a hydroxyl end group, improved the tensile properties noticeably in comparison with those based on the normal POM matrix. The composites were strengthened with an increase in the concentration of the functional groups. The results of scanning electron microscopy observations indicated that the fractured surfaces of a specimen having maximum tensile strength and elongation exhibited cohesion of the modified POM on the surfaces of the glass fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Fractalkine mediates T cell–dependent proliferation of synovial fibroblasts in rheumatoid arthritis
Authors: Sawai Hirokazu , Park Yong W. , He Xiaowen , Goronzy Jörg J. , Weyand Cornelia M.
Published: September 2007

Objective

In rheumatoid arthritis (RA), synovial fibroblasts proliferate excessively, eventually eroding bone and cartilage. The aim of this study was to examine the mechanisms through which CD4 T cells, the dominant lymphocyte population in patients with rheumatoid synovitis, regulate synoviocyte proliferation.

Methods

Fibroblast‐like synoviocyte (FLS) lines were established from rheumatoid synovium. CD4 T cells from patients with RA and age‐matched control subjects were cultured on FLS monolayers. FLS proliferation was quantified by cytometry, using carboxyfluorescein succinimidyl ester staining or microscopic enumeration of PKH26‐stained FLS. Surface expression of the fractalkine (FKN) receptor CX3CR1 was monitored by fluorescence‐activated cell sorting. The induction of CX3CR1 and its ligand FKN in FLS was quantified by real‐time polymerase chain reaction.

Results

The proliferation of FLS was significantly increased in the presence of CD4 T cells from patients with RA compared with control T cells. CD4+,CD28– T cells were particularly effective in supporting FLS growth, inducing a 25‐fold expansion compared with a 5‐fold expansion induced by CD4+,CD28+ T cells. The growth‐promoting activity of CD4+,CD28– T cells was mediated through CX3CR1, a chemokine receptor expressed on both T cells and FLS. Anti‐CX3CR1 antibodies inhibited T cell production of tumor necrosis factor α (TNFα) and suppressed FLS proliferation. TNFα amplified the expansion of FLS by enhancing their expression of CX3CR1 and FKN.

Conclusion

FKN–CX3CR1 receptor–ligand interactions regulate FLS growth and FLS‐dependent T cell function. FLS stimulate autocrine growth by releasing FKN and triggering the activity of their own CX3CR1. This growth‐promotion loop is amplified by TNFα produced by CX3CR1‐expressing T cells upon stimulation by FKN‐expressing FLS. These data assign a critical role to FKN and its receptor in fibroblast proliferation and pannus formation in RA.
Biomechanical signals inhibit IKK activity to attenuate NF‐κB transcription activity in inflamed chondrocytes
Authors: Dossumbekova Anar , Anghelina Mirela , Madhavan Shashi , He Lingli , Quan Ning , Knobloch Thomas , Agarwal Sudha
Published: September 2007

Objective

While the effects of biomechanical signals in the form of joint movement and exercise are known to be beneficial to inflamed joints, limited information is available regarding the intracellular mechanisms of their actions. This study was undertaken to examine the intracellular mechanisms by which biomechanical signals suppress proinflammatory gene induction by the interleukin‐1‐β (IL‐1β)–induced NF‐κB signaling cascade in articular chondrocytes.

Methods

Primary rat articular chondrocytes were exposed to biomechanical signals in the form of cyclic tensile strain, and the effects on the NF‐κB signaling cascade were examined by Western blot analysis, real‐time polymerase chain reaction, and immunofluorescence.

Results

Cyclic tensile strain rapidly inhibited the IL‐1β–induced nuclear translocation of NF‐κB, but not its IL‐1β–induced phosphorylation at serine 276 and serine 536, which are necessary for its transactivation and transcriptional efficacy, respectively. Examination of upstream events revealed that cyclic tensile strain also inhibited the cytoplasmic protein degradation of IκBβ and IκBα, as well as repressed their gene transcription. Additionally, cyclic tensile strain induced a rapid nuclear translocation of IκBα to potentially prevent NF‐κB binding to DNA. Furthermore, the inhibition of IL‐1β–induced degradation of IκB by cyclic tensile strain was mediated by down‐regulation of IκB kinase activity.

Conclusion

These results indicate that the signals generated by cyclic tensile strain act at multiple sites within the NF‐κB signaling cascade to inhibit IL‐1β–induced proinflammatory gene induction. Taken together, these findings provide insight into how biomechanical signals regulate and reduce inflammation, and underscore their potential in enhancing the ability of chondrocytes to curb inflammation in diseased joints.
Evidence for a different anatomic basis for joint disease localization in polymyalgia rheumatica in comparison with rheumatoid arthritis
Authors: Marzo‐Ortega Helena , Rhodes Laura A. , Tan Ai Lyn , Tanner Steven F. , Conaghan Philip G. , Hensor Elizabeth M. A. , O'Connor Philip , Radjenovic Aleksandra , Pease Colin T. , Emery Paul , McGonagle Dennis
Published: September 2007

Objective

The anatomic basis for joint disease localization in polymyalgia rheumatica (PMR) is poorly understood. This study used contrast‐enhanced and fat suppression magnetic resonance imaging (MRI) to evaluate the relationship between synovial and extracapsular inflammation in PMR and early rheumatoid arthritis (RA).

Methods

Ten patients with new‐onset PMR and 10 patients with early RA underwent dynamic contrast‐enhanced MRI and conventional MRI of affected metacarpophalangeal (MCP) joints. Synovitis and tenosynovitis were calculated based on the number of enhancing voxels, initial rate of enhancement, and maximal enhancement of gadolinium diethylenetriaminepentaacetic acid (Gd‐DTPA). Periarticular bone erosion and bone edema were scored according to the OMERACT (Outcome Measures in Rheumatology Clinical Trials) scoring system in both groups. The degree of extracapsular Gd‐DTPA enhancement was assessed in both conditions using semiquantitative scoring.

Results

No significant differences were seen in the volume of synovitis (P = 0.294), degree of flexor tenosynovitis (P = 0.532), periarticular erosions (P = 0.579), or degree of bone edema (P = 0.143) between RA and PMR joints. However, despite comparable degrees of synovitis, the proportion of MCP joints showing extracapsular enhancement was higher in the PMR group (100%) than in the RA group (50%) (P = 0.030). One PMR patient, but none of the RA patients, had bone edema at the capsular insertion.

Conclusion

Despite degrees of synovitis and tenosynovitis comparable with those in RA, PMR‐related hand disease is associated with prominent extracapsular changes, suggesting that inflammation in these tissues is more prominent than joint synovitis, which is common in both conditions. This suggests that the anatomic basis for joint disease localization differs between RA and PMR.
Multicenter validation of a new quality of life measure in pediatric lupus
Authors: Moorthy L. Nandini , Peterson Margaret G. E. , Baratelli Maria , Harrison Melanie J. , Onel Karen B. , Chalom Elizabeth C. , Haines Kathleen , Hashkes Philip J. , Lehman Thomas J. A.
Published: September 2007

Objective

Pediatric systemic lupus erythematosus (SLE) is a chronic fluctuating disease that significantly impacts quality of life (QOL). There is no pediatric SLE‐specific health‐related QOL (HRQOL) scale. Our objective was to develop and validate a new pediatric SLE‐specific HRQOL scale.

Methods

We developed the Simple Measure of the Impact of Lupus Erythematosus in Youngsters (SMILEY) based on results of qualitative research of children with SLE and their parents. SMILEY has parallel child and parent reports with a 5‐faces scale for responses. SMILEY comprises 4 domains: effect on self, limitations, social, and burden of SLE. In this cross‐sectional study, we examined face, content, construct, and concurrent validity; internal consistency; test–retest reliability; and child‐parent agreement for SMILEY. Children ≤18 years of age with SLE and their parents completed corresponding child and parent SMILEY reports, as well as other QOL and physical function scales. Qualified physicians assessed SLE activity, damage, and severity.

Results

Eighty‐six children with SLE and 80 parents participated. SMILEY was found to have face, content, construct, and concurrent validity (Spearman's rank correlation [rs] ≥0.4); test–retest reliability (intraclass correlation coefficient [ICC] 0.9); and internal consistency (α = 0.9). Moderate agreement was found between child and parent SMILEY reports (ICC 0.7, rs = 0.5, P < 0.001).

Conclusion

SMILEY is a brief, easily understood, valid, and reliable pediatric SLE‐specific QOL scale. Because SMILEY assesses children's self‐perception of QOL as impacted by SLE, we predict that it will have great utility in clinical practice, clinical trials, and outcomes research.
Predictability of the clinical course of juvenile dermatomyositis based on initial muscle biopsy: A retrospective study of 72 patients
Authors: Miles L. , Bove K. E. , Lovell D. , Wargula J. C. , Bukulmez H. , Shao M. , Salisbury S. , Bean J. A.
Published: September 2007

Objective

Except when the diagnosis of juvenile dermatomyositis (DM) is in doubt, a case has not been made for routine muscle biopsy (MB). We sought to determine whether MB findings prior to systemic therapy have prognostic value.

Methods

We reviewed the hospital records and slides prepared from the initial open MB of 72 patients treated at one center between 1977 and 2002 and followed for a minimum of 2 years. None of the patients had received a course of systemic corticosteroid therapy at the time of MB. Our approach to MB evaluation was based on recent discussions with muscle pathology experts to develop criteria for assessing inflammation, vasculopathy, myofiber atrophy, regeneration, acute and chronic myopathic change, and stromal changes. Using simple and multivariate logistic regression, we tested each MB parameter for ability to predict outcome using 2 published classification systems.

Results

Extensive active myopathic changes (excluding regeneration) and central nuclei without basophilia predicted chronic juvenile DM. Severe arteropathic change, positive arterial direct immunofluorescence, obvious foci of severe capillary loss/endomysial fibrosis, and muscle infarcts predicted chronic juvenile DM, particularly with ulceration. Other MB parameters, regardless of severity, were not significant predictors of chronic juvenile DM versus limited disease.

Conclusion

A scoring system for evaluating pretreatment MB in juvenile DM that focuses on extent of necrotizing myopathy, severity of vasculopathy, and features of established chronicity such as central nucleation of nonbasophilic myofibers may provide a basis for stratification of therapeutic regimens according to risk for chronic disease. The validity of our findings should be prospectively tested.
The importance of the disease process and disease‐modifying antirheumatic drug treatment in the development of septic arthritis in patients with rheumatoid arthritis
Authors: Edwards Christopher J. , Cooper Cyrus , Fisher David , Field Max , van Staa Tjeerd P. , Arden Nigel K.
Published: September 2007

Objective

To evaluate the effect of disease‐modifying antirheumatic drugs (DMARDs) on the likelihood of patients with rheumatoid arthritis (RA) developing septic arthritis (SA).

Methods

The United Kingdom General Practice Research Database (GPRD) was used to identify adults with RA, and age‐, sex‐, and practice‐matched control subjects. Subjects were studied between 1987 and 2002. The risk of developing SA (excluding infected joint replacements) for individuals with RA was calculated and the effect of DMARD use determined.

Results

A total of 136,977 subjects (34,250 patients with RA, 102,747 controls) were identified. SA was identified in 345 subjects, of which 321 (236 in patients with RA, 85 in controls) cases occurred during the study period. The incidence rate of SA was 12.9 times higher in subjects with RA than in those without (95% confidence interval [95% CI] 10.1–16.5, P < 0.001). The incident rate ratios (IRRs) for developing SA while receiving DMARDs compared with receiving no DMARDs were different for different medications. Penicillamine (adjusted IRR 2.51, 95% CI 1.29–4.89, P = 0.004), sulfasalazine (adjusted IRR 1.74, 95% CI 1.04–2.91, P = 0.03), and prednisolone (adjusted IRR 2.94, 95% CI 1.93–4.46, P < 0.001) were associated with an increased incidence of SA when compared with not receiving any DMARD. The use of other DMARDs including methotrexate showed no such effect.

Conclusion

Individuals with RA have an increased risk of developing SA. This increased risk can be attributed to both the disease process and the use of DMARDs.
The Mitsunobu Reaction: Origin, Mechanism, Improvements, and Applications
Authors: But Tracy Yuen Sze , Toy Patrick H.
Published: September 2007

The Mitsunobu reaction is a widely used and versatile method for the dehydrative oxidation–reduction condensation of an acid/pronucleophile usually with a primary or secondary alcohol that requires the combination of a reducing phosphine reagent together with an oxidizing azo reagent. The utility of this reaction stems from the fact that it is generally highly stereoselective and occurs with inversion of the stereochemical configuration of the alcohol starting material. Furthermore, as carboxylic acids, phenols, imides, sulfonamides, and other compounds can be used as the acid/pronucleophile, this reaction is useful for the preparation of a wide variety of functional groups. This Focus Review of the Mitsunobu reaction summarizes its origins, the current understanding of its mechanism, and recent improvements and applications.
Synthesis and Aggregation Behavior of meso‐Sulfinylporphyrins: Evaluation of S‐Chirality Effects on the Self‐Organization to S–Oxo‐Tethered Cofacial Porphyrin Dimers
Authors: Matano Yoshihiro , Shinokura Tomonori , Matsumoto Kazuaki , Imahori Hiroshi , Nakano Haruyuki
Published: September 2007

The synthesis and aggregation behavior of meso‐sulfinylporphyrins are described. The copper‐catalyzed C–S cross‐coupling reaction of a meso‐iodoporphyrin with benzenethiol and n‐octanethiol has proved to be an efficient method for the synthesis of meso‐sulfanylporphyrins, which are oxygenated by m‐chloroperbenzoic acid to produce the corresponding meso‐sulfinylporphyrins. Optically active zinc meso‐sulfinylporphyrins were successfully isolated by means of optical resolution of the racemates on a chiral HPLC column. Zinc sulfinylporphyrins readily undergo self‐organization through S–oxo–zinc coordination to form cofacial porphyrin dimers in solution, in which the hetero‐ and homodimers are present as a diastereomeric mixture. The aggregation modes of the S–oxo‐tethered porphyrin dimers were fully characterized by 1H NMR, IR, and UV/Vis spectroscopy as well as DFT calculations on their model compounds, thus revealing that the self‐aggregation behavior depends on the combination of S chirality. The absolute configurations at the sulfur center can be determined by the exciton‐coupled CD method. The observed self‐association constant for the S–oxo‐tethered dimerization of (S)‐phenylsulfinylporphyrin in toluene is larger than that in dichloromethane, which reflects the difference in dipole moments between the homodimer and the monomer. In cyclic and differential pulse voltammetry, the first oxidation process of the cofacial dimers is split into two reversible steps, which indicates that the initially produced π radical cations are delocalized efficiently between the two porphyrin rings. The present findings demonstrate the potential utility of meso‐sulfinyl groups as promising ligands for investigating the effects of peripheral chirality on the structures and optical and electrochemical properties of metal‐assisted porphyrin self‐assemblies.
Betonkorrosion durch Schwefelsäure an Abwasserbauwerken. Innovative Schadensdiagnose
Authors: Taffe Alexander , Pohl Markus , Roeser Wolfgang , Schwamborn Bernd
Published: September 2007

Zur erfolgreichen Instandsetzung geschädigter Stahlbetonbauwerke sind verlässliche Daten aus Bauwerksuntersuchungen und darauf basierende Schlussfolgerungen durch den sachkundigen Planer unabdingbar. Während im Fall tausalzinduzierter Korrosion die Vorgehensweise bei der Untersuchung und Instandsetzung in der Praxis gut bekannt und geregelt ist, trifft dies bei Schäden an Abwasserbauwerken und Biogasanlagen durch biogene Schwefelsäure nicht zu. In diesem Beitrag wird gezeigt, welche Aussagen mit klassischen Prüfungen wie chemischer Analyse und Oberflächenzugfestigkeitsprüfung im Vergleich zu einem neu entwickelten Verfahren wie der Laser‐induzierten Breakdown Spektroskopie (LIBS) gewonnen werden können. Es werden die Möglichkeiten aber auch Grenzen dieser Verfahren bei der Bauwerksdiagnose im Fall von biogenem Schwefelsäureangriff beschrieben.
Experimental and Numerical Simulation Study of Heat Transfer Due to Confined Impinging Circular Jet
Authors: Chang‐geng L. , Jie‐min Z.
Published: September 2007

An experimental and numerical simulation study of heat transfer due to a confined impinging circular jet is presented. In this research, a stainless steel foil heated disk was used as the heat transfer surface of a simulated chip, and the thermocouples were mounted symmetrically along the diameter of the foil to measure the temperature distribution on the surface. Driven by a small pump, a circular air jet (1.5 mm and 1 mm in diameter) impinged on the heat‐transfer surface with middle and low Reynolds numbers. The parameters, such as Reynolds number and ratio of height‐to‐diameter, were changed to investigate the radial distribution of the Nusselt number and the characteristics of heat transfer in the stagnation region. Numerical computations were performed by using several different turbulence models. In wall bounded turbulent flows, near‐wall modeling is crucial. Therefore, the turbulence models enhanced wall treatment, such as the RNG κ‐ϵ model, may be superior for modeling impingement flows. The numerical results showed reasonable agreement with the experimental data for local heat transfer coefficient distributions. The impinging jet may be an effective method to solve the cooling problem of high power density electronic packaging.
Evaluation of Electro‐Oxidation of Textile Effluent Using Response Surface Methods
Authors: Saravanathamizhan R. , Mohan N. , Balasubramanian N. , Ramamurthi V. , Basha C. Ahmed
Published: September 2007

In the present investigation, treatment of textile effluent using an electrochemical technique was designed and analyzed using the Box‐Behnken method. The influence of individual parameters on electro‐oxidation of textile effluent has been critically examined using the response surface method (RSM), and a quadratic model for chemical oxygen demand (COD) reduction has been developed. It has been observed from the present analysis that the predicted values are in good agreement with experimental data with a correlation coefficient of 0.945.
Concentrations and Seasonal Trends of Extracellular Microcystins in Freshwaters of the Czech Republic – Results of the National Monitoring Program
Authors: Bláhová Lucie , Babica Pavel , Maršálková Eliška , Maršálek Blahoslav , Bláha Ludek
Published: September 2007

The first outcomes of the national monitoring program on cyanobacteria and their toxins in the Czech Republic are reported. The concentrations of extracellular microcystins (MCs, analyzed by ELISA) in 206 water samples collected from 94 localities have been investigated. Observed MC concentrations were relatively high in comparison with the literature data, although weather conditions during the covered season (year 2004) were less favorable for the cyanobacterial water blooms. Detectable MCs (>0.125 μg/L) were found in 145 waters (70% of all samples) with a median concentration of 0.67 μg/L. The total median, including samples with no detectable MCs, was 0.26 μg/L. The seasonal trend showed an increase from July to September at most localities (maximum concentrations of about 8 μg/L and extremes up to 37 μg/L). However, a peak at the beginning of the season or continuously elevated MC concentrations were also observed at some localities. Positive correlations between increasing concentrations of MCs and the dominancy of Microcystis spp. have been observed. The survey provides the first large‐scale study of the occurrence and seasonal variability of extracellular microcystins that are of particular interest for drinking water management.
Chemical Aspects of Fractional Crystallization of Fatty Acid Methyl Esters Produced from Waste Fats
Authors: Sahlabji Taher , Wichmann Hubertus , Dieckmann Heike , Jopke Petra , Bahadir Müfit
Published: September 2007

Fractional crystallization of fatty acid methyl esters (FAME) produced from waste cooking oil or animal fats was performed in a laboratory‐scale facility. The raw esters and the “winterization” products were analyzed by determining the FAME pattern, iodine and peroxide numbers as well as oxidation stabilities and element concentrations. Fractionation experiments under air and nitrogen were conducted, but no differences concerning oxidative stability were observed. By improvement of the winterization and washing the filtration residue with methanol, the enrichment of saturated FAME in one step was raised up to a technically sufficient rate of 85%. Absorption of oxygen by FAME at different temperatures was measurable. Volatile decomposition products were registrated after heating the FAME at different temperatures. It was shown that antioxidants like butylhydroxytoluene or α‐tocopherol were enriched in the phase of unsaturated FAME. This effect obviously affected the oxidative stability of the fraction of saturated FAME during winterization, although no oxidative damage of FAME was detectable at temperatures up to 20°C.
Heavy Metal Removal from Soils Using Magnetic Separation: 1. Laboratory Experiments
Authors: Feng Nan , Bitton Gabriel , Yeager Philip , Bonzongo Jean‐Claude , Boularbah Ali
Published: September 2007

The removal of Cu, Zn, and Cd from a sandy soil was investigated using iron filings as an adsorbent, and subsequently recovering the iron filings by magnetic separation. The best treatment was obtained by using 5% iron filings and 3 h contact time between iron filings and the soil. The metal removal efficiency from soil extracts was evaluated, using MetPLATETM, a toxicity test that is specific for heavy metals, and the 48 h Ceriodaphnia dubia acute toxicity test. The toxicity removal was generally higher than 95% for Cu after a single treatment. With regard to Zn‐spiked soil, the toxicity removal was 96.1%, 70.0%, and 49.6% after single treatment at the input concentration of 200 mg/kg, 400 mg/kg, and 800 mg Zn2+/kg soil, respectively. After two or three successive treatments, more than 90% of the toxicity was removed for 400 mg/kg and 800 mg/kg Zn‐spiked soils. In the case of Cd‐spiked soil, a single treatment removed 51.1% of the toxicity from 200 mg/kg Cd‐spiked soil extracts while more than 90% of the toxicity was removed after two or three treatments. Chemical analysis and a mass balance study were also carried out to investigate the Cu distribution in the soil fractions. The results indicate that, before treatment, a large portion of Cu was immobilized in the soil matrix. Following magnetic separation, Cu was removed from both the soil matrix and extracts and was indeed adsorbed and concentrated on the iron filings. The retrieval of Cu by iron filings was further examined by energy dispersive X‐ray spectroscopy (EDS).
Synthesis, Enantiomeric Resolution, and Structure–Activity Relationship Study of a Series of 10,11‐Dihydro‐5H‐Dibenzo[a,d]cycloheptene MT2 Receptor Antagonists
Authors: Spadoni Gilberto , Bedini Annalida , Diamantini Giuseppe , Tarzia Giorgio , Rivara Silvia , Lorenzi Simone , Lodola Alessio , Mor Marco , Lucini Valeria , Pannacci Marilou , Caronno Alessia , Fraschini Franco
Published: September 2007

Racemic N‐(8‐methoxy‐10,11‐dihydro‐5H‐dibenzo[a,d]cyclohepten‐10‐ylmethyl)acetamide (compound 5) was previously identified as a novel selective MT2 antagonist fulfilling the requirements of pharmacophore and 3D QSAR models. In this study the enantiomers of 5 were separated by medium‐pressure liquid chromatography and behaved as the racemate. Compound 5 was modified at the acylaminomethyl side chain and at position C8. The resulting analogues generally behaved as melatonin receptor antagonists (GTPγS test) with a modest degree of selectivity (up to 10‐fold) for the MT2 receptor. Changes at the amide side chain led to a decrease in binding affinity, whereas 8‐acetyl and 8‐methyl derivatives 12 and 11, respectively, were as potent as the 8‐methoxy parent compound 5. Docking experiments with an MT2 receptor model suggested binding modes consistent with the observed SARs and with the lack of selectivity of the enantiomers of 5.
Prostate cancer prevention
Authors: Fleshner Neil , Zlotta Alexandre R.
Published: September 2007

Prostate cancer is the most common male malignancy and the second or third leading cause of cancer death among men in the West. The descriptive epidemiology of prostate cancer suggests that it is a preventable disease. Prevention has the theoretical advantage of not only saving lives, but also reduce the morbidity of radical prostate cancer therapy. This article reviews the past, present, and future of prostate cancer prevention. In particular, the evidence and scientific data of a variety of prevention strategies are reviewed. Strategies reviewed include dietary fat reduction and supplementation with vitamins D and E, and selenium. Dietary intake of soy, green tea, and tomato‐rich products (lycopene) are also reviewed. Data regarding pharmacological intervention with cyclo‐oxygenease inhibitors, antiestrogens, and in particular 5‐alpha reductase inhibitors are reviewed. The results of the Prostate Cancer Prevention Trial including the controversy surrounding higher‐grade cancers among men randomized to finasteride are also summarized. Finally, a variety of trial designs as well as a roster of current phase 2 trials are presented. Probably no cancer is being investigated more thoroughly in the context of prevention as prostate cancer in 2007. Definitive answers to pivotal phase 3 trials will be available in the coming 2 to 7 years. Cancer 2007. © 2007 American Cancer Society.
Fluorescence in situ hybridization for detecting genomic alterations of cyclin D1 and p16 in oral squamous cell carcinomas
Authors: Uzawa Narikazu , Sonoda Itaru , Myo Kunihiro , Takahashi Ken‐Ichiro , Miyamoto Ryozo , Amagasa Teruo
Published: September 2007

BACKGROUND

Cyclin D1 (CCND1) and p16 alterations have been detected in oral squamous cell carcinomas (SCCs), suggesting that abnormalities of these genes may play an important role in the genesis or progression of oral SCCs and serve as independent prognostic indicators. The detection of CCND1 and p16 aberrations using a simple and sensitive method would be valuable for the development of effective treatment modalities for oral cancer. The objective of the current study was to determine whether CCND1 numerical aberrations and p16 deletions in oral SCCs detected by fluorescence in situ hybridization (FISH) have any impact on clinical outcome.

METHODS

Using genomic DNA probes for CCND1 and p16, FISH was performed on specimens that were obtained by fine‐needle aspiration (FNA) from 57 primary oral SCCs.

RESULTS

The CCND1 numerical aberration was observed in 28 of 57 patients (49%) with oral SCCs and was associated significantly with reduced disease‐free survival (P = .0004) and overall survival (P = .0179). Conversely, p16 deletion was detected in 22 of 57 patients (39%). The disease‐free and overall survival rates for patients with p16 deletion were lower than those among patients without the p16 deletion, although the difference just failed to reach statistical significance (P = .0516 and P = .1878, respectively). The p16 deletion in the presence of the CCND1 numerical aberration conferred significantly worse disease‐free survival (P = .0002) and overall survival (P = .0153).

CONCLUSIONS

Although the CCND1 numerical aberration was a good predictor of aggressive tumors, recurrence, and poor prognosis in patients with oral SCCs, the authors were able to identify subgroups of patients that had early disease recurrence and a poor prognosis more efficiently by assessment of p16 deletion in addition to CCND1 genetic status using FISH on FNA biopsy samples compared with the analysis of either alteration alone. Cancer 2007. © 2007 American Cancer Society.
Stem cell plasticity: Learning from hepatogenic differentiation strategies
Authors: Banas Agnieszka , Yamamoto Yusuke , Teratani Takumi , Ochiya Takahiro
Published: September 2007

Many studies on stem cell plasticity are challenging the concept that stem cells contain an intrinsically predefined, unidirectional differentiation program. This means that the developmental fate of a stem cell is dependent on the general potential of the cell (pre‐determined stem cell fate) as well as on microenvironmental cues, such as stimuli from growth factors (stem cell niche). Here, we reviewed reports that examined the hepatocyte differentiation ability of stem cells from two different sources: embryonic stem cells and adult stem cells. All of those stem cells revealed the ability to give rise to hepatocyte‐like cells using different induction strategies. However, it is still not clear which of those stem cells would be the best source for hepatocyte replacement or which would be the best protocol. We herein present the current knowledge regarding available protocols and factors used in order to obtain functional hepatocytes from stem cells. Developmental Dynamics 236:3228–3241, 2007. © 2007 Wiley‐Liss, Inc.
Investigation of the polarization characteristics of GaInAsSb‐covered inAs quantum dots for application to surface‐emitting devices
Authors: Matsuura Tetsuya , Miyamoto Tomoyuki , Koyama Fumio
Published: September 2007

Self‐assembled InAs quantum dots are expected to be applied as active layers for long‐wavelength emitting devices used in fiber‐optic communications. A problem with these is the deterioration of emission efficiency accompanying the accumulation of strain from increasing wavelengths to beyond the 1.3‐µm range on GaAs substrates. However, with the application of a GaInAsSb covering layer containing a small quantity of antimony (Sb), as proposed in this research, it will become possible to improve the emission efficiency and to have long‐wavelength emission in the 1.5‐µm band. Meanwhile, in order to use such quantum dots as surface‐emitting devices, the in‐plane polarization characteristics must be clarified. However, the polarization characteristics of quantum dots containing Sb have not been reported before now. In this paper, we focus on the influence on the emission characteristics of the transformation of the dot shape due to the addition of Sb. The polarization characteristics of photoluminescence due to the addition of Sb and of In to the cover layer are measured, the dependency of the polarization degree on the dot structure is evaluated, and guidelines for surface‐emitting‐type device applications are given. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(10): 1–8, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20352
Multi‐keyhole model for MIMO repeater system evaluation
Authors: Tsuruta Makoto , Karasawa Yoshio
Published: September 2007

Enhancement of service to closed spaces (independent spaces) via a repeater with several transmission lines is attracting attention as a means of expanding the service area of information transmission by MIMO. The propagation path in such environments becomes a multi‐keyhole environment in the equivalent sense. The existence of a keyhole causes a reduction of communication capacity. However, in a multi‐keyhole environment, the impact is reduced because multi‐stream transmission becomes possible. In this paper, we propose a MIMO repeater system and a multi‐keyhole model that realize repeater functions to a closed space while high‐speed and high‐reliability communication characteristic to MIMO are maintained. The eigenvalue distribution, average communication capacity, and average BER characteristics of the MIMO repeater channel are ascertained by computer simulations. The number of repeater antennas needed for relaying with the MIMO function maintained is determined. ©2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(10): 40–48, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20384
A practical network management system based on an organization hierarchy mobile agent model
Authors: Takahashi Kazuhide , Kon Takashi , Akiyama Kazuyoshi , Jinguji Makoto
Published: September 2007

A mobile communication network is composed of a tremendous number of diverse network elements (NEs), which are distributed over a wide geographical area. The system that monitors messages (including warnings) from the NEs and controls the NEs is called the network management system (NMS). Since the NMS is required to handle a large number of messages, it has been implemented with expensive large‐scale UNIX servers. Thus, the communication carrier is forced to invest a large amount in the hardware and middleware of the NMS. Another problem is that the carrier must follow the vendor strategy, such as migration to next‐generation hardware and OS upgrades. The authors have devised the organization hierarchy agent model (OHAM), in which the external specification of the NMS is represented at the data level as agent behavior, making it possible to add new external specifications quickly and flexibly to the NMS as functions. This paper describes the organization hierarchy mobile agent model (OHMAM), which achieves high processing capacity by upgrading the OHAM agents to mobile agents that move rapidly between small‐scale IA servers. A practical commercial system was formed by using the proposed model, and the results of its basic performance evaluation and reliability evaluation are presented in this paper. In the implementation of the proposed model, IA servers, which are inexpensive and readily available, are used as hardware. Open source software (OSS) such as Linux/JavaVM/PostgreSQL is actively used as OS/middleware. Thus, the total cost of ownership (TCO) of the NMS can be greatly reduced. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(10): 84–102, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20391