bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitive detection of small cell lung carcinoma cells by reverse transcriptase–polymerase chain reaction for prepro–gastrin‐releasing peptide mRNA
Authors: Saito Tsuyako , Kobayashi Makoto , Harada Ryoji , Uemura Yoshiki , Taguchi Hirokuni
Published: May 2003

BACKGROUND

Gastrin‐releasing peptide (GRP) is an autocrine growth factor in patients with small cell lung carcinoma (SCLC). The authors developed a reverse transcriptase‐polymerase chain reaction (RT‐PCR) assay for the detection of SCLC cells in the peripheral blood and the pleural effusion using preproGRP mRNA as a target.

METHODS

The current study was conducted to determine the utility of preproGRP‐specific nested RT‐PCR on the peripheral blood, bone marrow, and pleural effusion samples from 32 patients with SCLC, 39 patients with non‐small cell lung carcinoma (NSCLC), 28 patients with nonmalignant pulmonary disease, and 20 healthy volunteers. The internal primers were designed to amplify a 244‐base pair PCR product, a sequence encompassing exon 1 and exon 2 by the nested RT‐PCR assay.

RESULTS

Amplification of the preproGRP message was detected in SCLC cell lines (LU165, SBC1, SBC2, and SBC3) but not in other NSCLC cell lines (A549, ABC1, EBC1, and Oka‐1). The SCLC cells (LU165) were detected in dilutions of tumor cells of up to 10−7 in hematopoietic cells from healthy donors. The preproGRP mRNA was detected in 16 of 32 (50%) blood samples, 2 of 11 (18%) marrow samples, and in all 6 (100%) pleural effusion samples. Blood samples gave positive results in 11 of 19 (58%) patients with extensive disease compared with 5 of 13 (38%) patients with limited disease. In contrast, only 1 blood sample (2.6%) from a patient with lung adenocarcinoma gave a positive result among patients with NSCLC. No other samples of blood, bone marrow, and pleural effusion from patients with NSCLC and none of the blood samples from patients with nonmalignant diseases and healthy volunteers were positive.

CONCLUSIONS

The current RT‐PCR approach may be a sensitive and specific assay to detect SCLC cells in circulating blood as well as in pleural effusions from SCLC patients. Cancer 2003;97:2504–11. © 2003 American Cancer Society.

DOI 10.1002/cncr.11378
Primary gastrointestinal lymphoma in Japan
Authors: Nakamura Shotaro , Matsumoto Takayuki , Iida Mitsuo , Yao Takashi , Tsuneyoshi Masazumi
Published: May 2003

BACKGROUND

An optimal treatment modality for patients with primary gastrointestinal lymphoma has not yet been established. This study aimed to elucidate the clinicopathologic features of this disease and the influence of therapeutic modalities on the prognosis in Japanese patients

METHODS

The clinicopathologic features of 455 patients with primary gastrointestinal lymphoma were investigated retrospectively regarding treatment modalities and time trends.

RESULTS

This study comprised 342 patients (75%) with gastric lymphoma, 96 patients (22%) with intestinal lymphoma, and 17 patients (4%) with both gastric and intestinal lymphoma. Two hundred thirty‐one (51%) patients were classified as having low‐grade B‐cell lymphoma including 200 marginal zone lymphoma of mucosa‐associated lymphoid tissue (MALT) type, 185 (41%) patients were classified as having high‐grade B‐cell lymphoma including 76 diffuse large cell lymphoma plus MALT lymphoma, and 39 (9%) patients were classified as having T‐cell lymphoma. The frequency of nonsurgical treatment, including Helicobacter pylori eradication, chemotherapy, and radiation, increased during the latest decade. Patients who received nonsurgical treatment showed a better overall survival than those treated by surgery, but event‐free survival did not differ between two groups. Cox multivariate analysis revealed that early stage, younger age, gastric localization, B‐cell phenotype, and absence of B symptoms were independent prognostic factors for better overall and event‐free survivals. Mucosa‐associated lymphoid tissue‐derived lymphoma was also an independent prognostic factor for event‐free survival, but not for overall survival.

CONCLUSIONS

Nonsurgical treatment may be an optimal therapeutic modality for patients with primary gastrointestinal lymphoma. Cancer 2003;97:2462–73. © 2003 American Cancer Society.

DOI 10.1002/cncr.11415
Region‐specific effects of glia on neuronal induction and differentiation with a focus on dopaminergic neurons
Authors: Hall Anita C. , Mira Helena , Wagner Joseph , Arenas Ernest
Published: May 2003

Radial glia (RG) are the first glial cell type to appear in the nervous system. Their broad distribution and apparent similarity hide important brain region‐specific differences that are likely to be essential for development. However, recent evidence supports the stimulating concept that in addition to their classical function as neuroblast guides, RG are neuronal precursors (Malatesta et al. Development 127:5253–5263, 2000; Miyata et al. Neuron 31:727–741, 2001; Noctor et al. Nature 409:714–720, 2001; Skogh et al. Mol Cell Neurosci 17:811–820, 2001). We propose that RG not only generate and guide newborn neurons, but could also instruct their own neuronal progeny to adopt appropriate region‐specific phenotypes. GLIA 43:47–51, 2003. © 2003 Wiley‐Liss, Inc.
Formation of hydroxyapatite in water, Hank's solution, and serum at physiological temperature
Authors: Yadav K. L. , Brown Paul W.
Published: May 2003

The influence of de‐ionzed water, Hank's saline solution, and bovine calf serum on formation of stoichiometric (Ca/P = 1.67) hydroxyapatite (SHAp) at physiological temperature was studied. SHAp formed in aqueous solution by acid–base reaction of particulate Ca(H2PO4)2·H2O and Ca4(PO4)2O. Hydroxyapatite formation is accompanied by an initial period of surface hydration of the precursors, an induction period, and a period during which the bulk of the conversion to hydroxyapatites occurs. The formation of SHAp occurred more rapidly in Hank's solution and distilled water than in serum. The formation of SHAp from these precursors is strongly inhibited by serum. There were two primary exothermal events associated with SHAp formation: initial heat evolution peak, which was associated with reactant dissolution, and the major heat evolution peak, which was associated with SHAp formation. The presence of the constitutents in serum depresses both. This is a result of serum macromolecules adsorbing onto the available surfaces regardless of whether they are reactants or products. Variations in heat evolution behavior, pH, and the times of disappearance of the reactants and appearance of SHAp correlate with one another. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 158–163, 2003.
Hydrogen embrittlement of Ni‐Ti superelastic alloy in fluoride solution
Authors: Yokoyama Ken'ichi , Kaneko Kazuyuki , Moriyama Keiji , Asaoka Kenzo , Sakai Jun'ichi , Nagumo Michihiko
Published: May 2003

Hydrogen embrittlement of Ni‐Ti superelastic alloy in a fluoride solution (0.2% APF) has been investigated by means of a tensile test (after immersion) and hydrogen thermal desorption analysis. Upon immersion, the tensile strength of the alloy decreased to the critical stress level of martensite transformation. Hydrogen desorption of the immersed specimens appeared with a peak at around 500°C. The amount of absorbed hydrogen in the alloy ranged from 100 to 1000 mass ppm when immersed in the fluoride solution for 2 to 24 h. The immersion in the fluoride solution led to the degradation of mechanical properties due to hydrogen embrittlement. The results of the present study imply that one reason that Ti and its alloys fracture in the oral cavity is the fact that hydrogen is absorbed in a fluoride solution, such as prophylactic agents. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 182–187, 2003
Fiber‐enriched double‐setting calcium phosphate bone cement
Authors: dos Santos Luís Alberto , Carrodéguas Raúl Garcia , Boschi Anselmo Ortega , Fonseca de Arruda Antônio Celso
Published: May 2003

Calcium phosphate bone cements are useful in orthopedics and traumatology, their main advantages being their biocompatibility and bioactivity, which render bone tissue osteoconductive, providing in situ hardening and easy handling. However, their low mechanical strength, which, in the best of cases, is equal to the trabecular bone, and their very low toughness are disadvantages. Calcium phosphate cement compositions with mechanical properties more closely resembling those of human bone would broaden the range of applications, which is currently limited to sites subjected to low loads. This study investigated the influence of added polypropylene, nylon, and carbon fibers on the mechanical properties of double setting α‐tricalcium phosphate‐based cement, using calcium phosphate cement added to an in situ polymerizable acrylamide‐based system recently developed by the authors. Although the addition of fibers was found to reduce the compression strength of the double‐setting calcium phosphate cement because of increased porosity, it strongly increased the cement's toughness (JIC) and tensile strength. The composites developed in this work, therefore, have a potential application in shapes subjected to flexure. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 244–250, 2003
Genipin‐crosslinked gelatin microspheres as a drug carrier for intramuscular administration: In vitro and in vivo studies
Authors: Liang Huang‐Chien , Chang Wen‐Hsiang , Lin Ko‐Jung , Sung Hsing‐Wen
Published: May 2003

Gelatin microspheres have been widely evaluated as a drug carrier. Nevertheless, gelatin dissolves rather rapidly in aqueous environments, making the use of the polymer difficult for the production of long‐term delivery systems. This adverse aspect requires the use of a crosslinking agent in forming nonsoluble networks in microspheres. However, the use of crosslinking agents such as formaldehyde and glutaraldehyde can lead to toxic side effects owing to residual crosslinkers. In an attempt to overcome this problem, a naturally occurring crosslinking agent (genipin) was used to crosslink gelatin microspheres as a biodegradable drug‐delivery system for intramuscular administration. Glutaraldehyde was used as a control. In the in vitro study, the morphology, dynamic swelling, and antienzymatic degradation of test microspheres were evaluated. In the in vivo study, the biocompatibility and degradability of test microspheres were implanted in the skeletal muscle of a rat model via intramuscular injection. The results obtained in the study suggested that crosslinking of gelatin microspheres with glutaraldehyde or genipin may produce distinct crosslinking structures. The water transport mechanism in both the glutaraldehyde‐ and genipin‐crosslinked gelatin microspheres exhibit anomalous behavior ranging from Fickian to Case‐II extremes. The increase of the swelling diameter for the genipin‐crosslinked microspheres was significantly less than that observed for the glutaraldehyde‐crosslinked microspheres. In the animal study, it was found that the degree in inflammatory reaction for tissues implanted with the genipin‐crosslinked microspheres was significantly less than that implanted with the glutaraldehyde‐crosslinked microspheres. Additionally, the degradation rate of the genipin‐crosslinked microspheres was significantly slower than their glutaraldehyde‐crosslinked counterparts. These results indicated that the genipin‐crosslinked gelatin microspheres may be used as a long‐acting drug carrier for intramuscular administration. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 271–282, 2003
Preparation and assessment of revised simulated body fluids
Authors: Oyane Ayako , Kim Hyun‐Min , Furuya Takuo , Kokubo Tadashi , Miyazaki Toshiki , Nakamura Takashi
Published: May 2003

A simulated body fluid (SBF) with ion concentrations approximately equal to those of human blood plasma has been used widely for in vitro assessment of the bioactivity of artificial materials and for the formation of bone‐like apatite on various substrates. The ion concentrations of a conventional SBF (c‐SBF) are, however, not exactly equal to those of blood plasma. In the present study, a revision of c‐SBF was made to prepare new SBFs (r‐SBF, i‐SBF, and m‐SBF) with ion concentrations equal to or closer to those of blood plasma. The ion concentrations of the r‐SBF and i‐SBF were designed to be equal to those of blood plasma in total and dissociated amounts, respectively. The m‐SBF was designed to have a total ion concentration equal to that of blood plasma, except for the concentration of HCO, which was set to the saturated level with respect to calcite. The ion concentrations and pH of the as‐prepared new SBFs were found to be equal to those of the nominal values. Upon sealed storage, the r‐SBF and i‐SBF showed no change in ion concentrations for up to 4 weeks at 5°C, and up to 2 weeks at 36.5°C, but thereafter they showed a decrease in HCO concentration and an increase in pH. Under the same storage conditions, the c‐SBF and m‐SBF showed no change in ion concentrations and pH values over a period of up to 8 weeks. These results indicate that the r‐SBF and i‐SBF are less stable than the c‐SBF and m‐SBF in terms of changes in ion concentrations relative to storage period. The m‐SBF is optimal for in vitro bioactivity assessment of artificial materials and for biomimetic production of bone‐like apatite. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 188–195, 2003
TGF‐β1‐induced Smad 3 binding to the Smad 7 gene: Knockout of Smad 7 gene transcription by sense phosphorothioate oligos, autoregulation, and effect on TGF‐β1 secretion: Bleomycin acts through TGF‐β1
Authors: Cutroneo Kenneth R. , Phan Sem H.
Published: May 2003

Bleomycin produces its fibrogenic effect, at least in part, by TGF‐β1 secretion. Treatment of IMR‐90 human embryonic lung fibroblasts with bleomycin at 0.5 μg/ml results in a 1.6‐fold increase of TGF‐β1 as determined by a specific ELISA assay for TGF‐β1 after acidification of the conditioned media. This elevation of TGF‐β1 secretion is furthermore enhanced in vivo by TGF‐β1 autoinduction of the TGF‐β1 gene. To demonstrate TGF‐β1 autoinduction, the fibroblasts were pretreated with 12.5 ng/ml TGF‐β1, washed extensively to remove any residual TGF‐β1, and then allowed to incubate for 24 h in AIM V synthetic serum‐free media. The media when assayed using the ELISA assay contained a 1.6‐fold increase of TGF‐β1. The distal promoter of the human TGF‐β1 gene contains a Smad 3 element (CAGGACA), which is homologous to the Smad 3 binding element motif (CAGA). The nuclear extracts of human embryonic lung fibroblasts treated for either 15 min or 24 h with TGF‐β1 did not demonstrate specificity of binding of a protein(s) to the homologous Smad 3 element as determined by cold wild‐type oligodeoxynucleotide competition experiments. However, specific Smad 3 binding to the Smad 3 element (GTCTAGAC) found in proximal promoter of the Smad 7 gene was observed by cold oligo competition and supershift assays using a goat polyclonal Smad 3 antibody in the presence and absence of an N‐terminal Smad 3 peptide. To determine the functionality of this Smad 3 binding to the Smad 3 element in the proximal promoter of the Smad 7 inhibitory gene to TGF‐β1 secretion, fibroblasts were transiently pretransfected with double‐stranded phosphorothioate oligo “decoys” containing the Smad 7/Smad 3 element in the presence of plasmin to convert latent TGF‐β1 to active TGF‐β1. Under these conditions, which simulate the in vivo situation of 2.2‐fold increase of total active TGF‐β1 was observed. Fibroblasts were also pretransfected with these double‐stranded oligo “decoys,” washed, then treated with TGF‐β1, washed and incubated in AIM V for an additional 24 h. In this latter experiment, a superinduction of TGF‐β1 secretion was observed. We propose that these oligo “decoys” bind Smad 3 preventing this initiation factor from binding to the Smad 7/Smad 3 element thereby decreasing the transcription of the Smad 7 gene. The decrease of the inhibitory Smad 7 would result in less binding of this Smad inhibitor to the Type I TGF‐β receptor and less antagonism of active TGF‐β1, more autoinduction of the TGF‐β1 gene, and more of the fibrogenic effects of TGF‐β1. J. Cell. Biochem. 89: 474–483, 2003. © 2003 Wiley‐Liss, Inc.
Genotyping of measles and mumps virus strains using amplification refractory mutation system analysis combined with enzyme immunoassay: A simple method for outbreak investigations
Authors: Samuel D. , Beard S. , Yang H. , Saunders N. , Jin L.
Published: May 2003

A simple method, based on a modification of the amplification refractory mutation system (ARMS), for genotyping outbreak strains of measles and mumps viruses and detecting these in a simple enzyme immunoassay (EIA) is described. Fifty‐three measles strains circulating at the time of an outbreak in London in 2000 and 26 strains circulating at the time of a mumps outbreak in Accrington, UK, in 1999 were investigated. All strains were genotyped by direct sequencing. ARMS primers were then designed to amplify the outbreak strain. The ARMS‐EIA for measles and mumps detected all 36 measles outbreak strains as genotype D6, and all 15 mumps outbreak strains as genotype F, respectively. The sensitivity and specificity of both the measles D6 and Mumps F genotype ARMS EIA was 100% compared with direct sequencing. The results show that ARMS‐EIA can be used as a rapid alternative to genotyping by direct sequence analysis in outbreak situations. J. Med. Virol. 69:279–285, 2003. © 2003 Wiley‐Liss, Inc.
Quantitation of human cytomegalovirus in recipients of solid organ transplants by real‐time quantitative PCR and pp65 antigenemia
Authors: Mengelle Catherine , Pasquier Christophe , Rostaing Lionel , Sandres‐Sauné Karine , Puel Jacqueline , Berges Laetitia , Righi Laurence , Bouquies Christiane , Izopet Jacques
Published: May 2003

Human cytomegalovirus (HCMV) infections and anti‐HCMV treatment are usually monitored by measuring pp65 antigenemia. This method is time‐consuming, labour‐intensive and requires skilled operators. We have compared results obtained using real‐time Light Cycler™ quantitative PCR (QPCR) and the pp65 antigen assay on serial samples collected from recipients of solid organ transplants. We collected 198 blood samples from 14 solid organ transplant recipients and assayed them for pp65 antigen and with Light Cycler™ PCR. HCMV DNA was extracted from leukocytes and measured using primers and probe located in the UL83 region. The quantity of HCMV DNA was calculated using a standard curve prepared from a plasmid containing the target sequence. There was a good correlation between the number of pp65‐positive cells and the DNA copy number (r = 0.57, P < 0.0001). A clinical threshold of 50 positive polymorphonuclear leukocytes/200,000 cells was equivalent to two log10 genome copies per capillary by Light Cycler™ PCR. HCMV DNA was detected before pp65 antigen in three patients at a mean time of 10 days, whereas the two tests were positive simultaneously for eight patients. Both the pp65 antigen data and DNA copy number decreased over time during antiviral treatment, although the QPCR was positive 28.2 days after the pp65 antigen assay had become negative. The real‐time Light Cycler™ quantitative PCR assay is a rapid and labour‐saving technique. This molecular method could be useful for monitoring infections and antiviral treatment in recipients of solid organ transplants. J. Med. Virol. 69:225–231, 2003. © 2003 Wiley‐Liss, Inc.
Rotavirus‐specific subclass antibody and cytokine responses in Bangladeshi children with rotavirus diarrhoea
Authors: Azim Tasnim , Zaki M. Hasan , Podder Goutam , Sultana Novera , Salam M. Abdus , Rahman S. Moshfiqur , Sefat‐e‐Khuda  , Sack David A.
Published: May 2003

Rotavirus‐specific subclass antibody responses and cytokines, tumour necrosis factor‐α (TNF‐α), interferon‐γ (IFN‐γ), interleukin‐8 (IL‐8), and IL‐10, were measured in children 7–24 months of age with rotavirus diarrhoea (n = 29); the responses were compared with children with watery diarrhoea from whom no enteric pathogens were isolated (controls; n = 11). All children had diarrhoea for <5 days and were enrolled from the Dhaka Hospital of the Centre for Health and Population Research. Samples of blood and stools were collected on the day of enrollment and 18–21 days after the onset of diarrhoea. Children showing a ≥4‐fold rise in antibody titre between the acute and convalescent stages were considered to have a response. The numbers of children with rotavirus‐specific IgA and IgA1 responses in stool were similar in the two groups of children. In the plasma, more children with rotavirus diarrhoea had rotavirus‐specific IgA, IgA1, IgG, IgG1, and IgG3 responses than did control children (P = 0.049, 0.007, 0.001, 0.002, and 0.012, respectively). IgA2 was not detectable. Among cytokines measured in supernatants from peripheral blood mononuclear cells (PBMCs) cultured for 6 and 24 hr, IFN‐γ was the only cytokine that was higher in children with rotavirus diarrhoea compared with controls (P = 0.013). Severity of illness did not correlate with nutritional status or antibody titres, but severity did correlate with TNF‐α during the acute stage of illness. IFN‐γ correlated positively with IgG1 titres. These findings suggest a role for IFN‐γ in the pathogenesis of rotavirus infection, but this needs confirmation by other studies. The immune responses described are relevant to future vaccine trials, as immune responses in vaccinees should mimic those in natural infection. J. Med. Virol. 69:286–295, 2003. © 2003 Wiley‐Liss, Inc.
Long‐Term Properties of Butt‐Welded Poly(propylene)
Authors: Schmachtenberg Ernst , Tüchert Carsten
Published: May 2003

It is still not clear why the long‐term properties of plastic weld seams can only be differentiated by the very expensive medium tensile creep tests. One hypothesis for justifying this is based on the change in the structure of the weld seam surroundings, another cites the consumption of antioxidants and the following ageing in the weld seam area to be responsible for this. Butt‐welded weld seams made of poly(propylene) were systematically produced under different process parameters. Corresponding to the particular hypothesis, these weld seams were then analyzed in various ways to find correlations or to prove one of the hypotheses. Regarding their short‐term weld seam quality, the analyzed weld seams could not be differentiated through short‐term tensile or short‐term bend test. However, the medium tensile creep tests showed significant differences in both time until failure and long‐term weld seam quality. Under long‐term loading, the start of the brittle crack could be detected in most weld seams in the fine spherulite‐zone or between this zone and the area of the flow lines. This demonstrated again that only long‐term tests are suitable for examining different weld seam qualities. Depending on the welding parameters, times until failure decline with increasing heated‐tool temperature and heating time. Though these parameters lead to a higher consumption of antioxidants in the weld seam, a degradation was not detected in the breaking area. In fact, increasing heated‐tool temperatures and heating times, as well as higher joining pressures lead to a change in the internal structure of the material. This can be seen in morphological structure analyses in the larger bend of the entire weld seam area. A larger bend, however, correlates with higher residual stresses in the weld seam. In the medium tensile creep tests, these residual stresses as well as the tensile stress in the border region and the compressive stress in the middle are superimposed by the tensile stress resulting from the test stress. Thus a greater bend of the weld seam area and higher residual stresses in the weld seam itself lead to shorter times until failure in medium tensile creep tests.

Schematic representation of the formation of residual stresses in a weld seam and residual stresses in the different bended weld seam areas.

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Schematic representation of the formation of residual stresses in a weld seam and residual stresses in the different bended weld seam areas.
An NMR‐MOUSE® for Analysis of Thin Objects
Authors: Blümich Bernhard , Anferov Vladimir , Anferova Sophia , Klein Martin , Fechete Radu
Published: May 2003

A special unilateral NMR sensor has been designed for investigations of thin samples with a thickness of less than 1 mm and of surface effects of polymers. For use with the bar‐magnet NMR‐MOUSE®, the so‐called “crazy coil” is introduced with a low penetration depth. It is a flat meander coil etched on a printed circuit board with wiggles in the conductors. The design of the new coil and FEM simulations of the B1 field are presented. Different applications are discussed by means of illustrative examples. They are the detection of surface damage in rubber samples, the swelling and drying of a latex membrane exposed to cyclohexane vapor mimicking a chemical sensor, and the drying of a thin sprayed adhesive layer.

Bar‐magnet NMR‐MOUSE® with crazy coil.

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Bar‐magnet NMR‐MOUSE® with crazy coil.
Preparation and Characterization of 4,4′‐Bis(4‐aminophenoxy)diphenyl Sulfone Based Fluoropoly(ether‐imide)/Organo‐Modified Clay Nanocomposites
Authors: Vora Rohit H. , Pallathadka Pramoda K. , Goh Suat Hong , Chung Tai‐Shung , Lim Yong Xiong , Bang Toong Kiang
Published: May 2003

A series of fluoropoly(ether‐imide) (6F‐PEI), and [6F‐PEI/montmorillonite (MMT) clay) nanocomposites films were made by thermal curing of respective formulations containing fluoropoly(ether‐amic acid) (6F‐PEAA), synthesized from 2,2′‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 4,4′‐bis(4‐aminophenoxy)diphenyl sulfone (p‐SED), and increasing concentration of p‐SED treated montmorillonite clay (modified MMT clay) at temperature from RT to 350 °C. These films showed excellent solvent resistance as well as very good thermal stability, and increased glass transition (Tg) values with increasing % clay. In addition, these trifluoromethyl groups‐containing nanocomposites films showed sharp lowering of coefficient of thermal expansion (CTE) by 22%. Furthermore, they exhibited increased long‐term thermo‐oxidative stability (TOS), with % weight retention in the range of 86 to 92% in isothermal heating at 300 °C for 300 h in air, reduced water absorption at 100 RH at 50 °C in the range of 0.5 to 1.15%. These data are still much lower than those of neat ULTEM® 1000 and Kapton® H film. The modulus of elasticity is on an average 38% higher for the nanocomposite films relative to neat fluoropoly(ether‐imide) (6FDA + p‐SED), and above non‐fluorinated polyimide films. The surface energy measurement by One‐Liquid and Two‐Liquid method showed a comparable trend of decreasing contact angle. For the nanocomposite films having 15% hydrophobic clay, the contact angle decreased by 21 and 20% for DI‐water and formamide, respectively. The surface energy increase was in the range of 8.21–8.54 mJ/m2.

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Study on the Curing Process and the Gelation of Epoxy/Anhydride System for No‐Flow Underfill for Flip‐Chip Applications
Authors: Zhang Zhuqing , Beatty Erin , Wong C. P.
Published: May 2003

No‐flow underfill is used in the assembly of microelectronics to increase the productivity and to decrease the cost of the flip‐chip manufacturing. The curing process, especially the gelation of the no‐flow underfill, is essential for the yield and reliability of the flip‐chip assembly. A differential scanning calorimeter (DSC) and a stress rheometer are used to study the curing process of epoxy/anhydride system at different curing rates and different isothermal temperatures. The gel point is found when the storage modulus and the loss modulus of the resin measured by the rheometer equals to each other. The degree of cure (DOC) at gelation is calculated according to the results from DSC. The results indicate a strong dependence of the DOC at gelation on the heating rates and the curing temperatures. In order to further investigate the difference in the curing process at various heating rates, FTIR spectra of the resin are taken during curing. The change of different functional groups is recorded and compared. The results do not show a significant difference in the chemical structure at different heating rates. The early gelation at high heating rate/ high temperature can be caused by the structure difference in the epoxy network at the early stage of curing due to the chain initiation and propagation of the molecules in the curing process.

Dependence of gelation of the sample on the isothermal temperatures.

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Dependence of gelation of the sample on the isothermal temperatures.
Three‐dimensional coplanar waveguide lowpass filters for MMIC applications
Authors: Lalehparvar Laleh , Budimir Djuradj
Published: May 2003

Shielded single and multilayer coplanar waveguide lowpass filter on GaAs and Si substrates in MMIC technology is presented and their performance is investigated with electromagnetic simulations. The filters are both Chebyshev type. The stepped‐impedance method is used in the design of the lowpass filter, where high‐ and low‐impedance line sections are cascaded together. The shielded single‐layer lowpass filter consists of three low‐ and two high‐impedance sections with characteristic impedances of 20Ω and 100Ω. The multilayer filter makes use of three low‐ and two high‐impedance lines with characteristic impedances of 5Ω and 120Ω, respectively. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 403–405, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10931
Design and analysis of MEM‐micromirrors for vertical‐cavity surface‐emitting lasers
Authors: Guan Yan , Matin M. A.
Published: May 2003

In this paper, we present aspects of designing and optimizing MEM‐micromirrors used in tunable vertical‐cavity surface‐emitting lasers (VCSELs). We also present four mirror models and their simulation results using CoventorWare software. According to our consideration of the aspects presented, the best model with optimal dimension has been chosen. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 410–413, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10934
A novel leaky‐wave antenna based on NRD guide with wedged cross section
Authors: Zeng Xiangyin , Xu Shanjia
Published: May 2003

A novel leaky‐wave antenna based on an NRD guide which not only possesses the merit of easy manufacture but also overcomes the difficulty of fixing the dielectric slab in the guide precisely, is proposed in this paper. Another attractive feature of this antenna is that the leakage and propagation constant can be separately controlled by means of choosing different geometric parameters. Thus it becomes possible to control the beam angle and the beamwidth of the antenna independently. Extensive numerical results are given to establish useful guidelines for the design of the new antenna. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 418–420, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10936
Design of unequal microstrip power divider using hierarchal genetic algorithm
Authors: Yuan Yuan , Chan Chi Hou , Man Kim Fung
Published: May 2003

This paper presents unequal microstrip power divider designs using the hierarchal genetic algorithm (HGA). The dividing ratio and return loss are the design specifications leading the evolution direction. By employing the HGA chromosome formulation, the system structure and its associated parameters can be minimized in a simultaneous manner. The computational performance of the design methodology is enhanced with the use of a parallel computing platform. The subsequent power dividers derived from the design have been fabricated, tested, and experimentally verified. Its performance matches very well with the result obtained from the simulation study. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 421–423, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10937
Semiconductor nonlinear device modeling using multiwavelets
Authors: Wang Ke , Pan George W. , Techentin R. , Gilbert B.
Published: May 2003

Modeling and simulation of seminconductor devices requires solution of highly nonlinear equations, such as the Boltzmann transport, hydrodynamic, and drift‐diffusion equations. The conventional finite‐element method (FEM) and finite difference (FD) schemes always result in oscillatory results, and are ineffective when the cell Reynolds number of the system is large. Several ad hoc schemes have been employed to address the instability issue, including the Scharfetter–Gummel transformation, Petrov–Galerkin method, and upwind algorithms; but each suffers from its shortcomings. We propose a new approach of the multiwavelet‐based finite‐element method (MWFEM) to solve the semiconductor drift‐diffusion system. In this approach, multiscalets are employed as the basis functions. Due to its ability of tracking the tendency, namely, the first derivative of the unknown function, the MWFEM shares the versatility of the conventional FEM while remaining stable in a highly nonlinear system. Comparison with the Scharfetter–Gummel method, upwind FEM, and conventional FEM shows that the MWFEM performs excellently under circumstances of both small‐ and large‐cell Reynolds numbers. A complete 1D drift‐diffusion solver base on the MWFEM is implemented. Numerical results demonstrate the high efficiency and accuracy of the new method. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 436–440, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10942
The study of a dual‐band internal handset antenna with a new compact 3D structure
Authors: Peng Hongli , Tang Song , Liu Qizhong
Published: May 2003

A dual‐band internal handset antenna (IHA) with a novel 3D structure is presented. Numerical results based on the finite‐element method (FEM) for input‐return loss and radiation‐gain pattern are investigated and compared with the measurements. Good agreement between the computed and measured results is obtained. The effects of the geometric parameters on the characteristics of the proposed antenna performance are also extensively studied. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 450–452, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10946
A compact broadside/endfire printed array antenna
Authors: Matzner H. , Sasson G. , Yacobi M. , Haridim M.
Published: May 2003

A novel double‐layer patch array antenna is presented. The proposed antenna consists of two identical parallel layers, each containing five patch elements. The antenna is fed through one of the elements in the lower layer while other elements act as parasitic antenna elements. Both simulated and experimental results show that the proposed antenna has a relatively high gain, low side‐lobes, and improved cross polarization. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 459–461, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10950
Mode mixing in an almost periodic azimuthally corrugated cavity
Authors: Serebryannikov A. E.
Published: May 2003

Deformation of a wall of an azimuthally corrugated periodic cavity leads to the mixing of the eigenmode fields of an originally periodic cavity. This effect manifests itself, in particular, in the splitting of what we refer to as natural frequency doublets. In this work, emphasis is placed on some typical features of the frequency and amplitude of an almost periodic cavity. In particular, the potential for compromising between the frequency rarefaction and amplitude composition are demonstrated for the cavity with a single and two irregular resonators, and some recommendations for their design are given. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 461–465, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10951
A novel photonic band‐gap microstrip structures for low‐pass filters of wide stop‐band
Authors: Liu Haiwen , Li Zhengfan , Sun Xiaowei , Mao Junfa
Published: May 2003

Two novel low‐pass filters (LPFs) of wide stop‐band are proposed in this paper. One filter is implemented by a photonic band‐gap (PBG) microstrip structure with T‐junction opened stubs and its frequency characteristics are discussed. The other filter is implemented by a PBG microstrip structure with cross‐junction opened stubs. The new wide‐band harmonic rejection LPFs are easy to design and fabricate. The simulated and experimental results verify the validity of the LPFs. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 470–472, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10953
Recent changes in riparian vegetation: possible consequences on dead wood processing along rivers
Authors: Tabacchi Eric , Planty‐Tabacchi Anne‐Marie
Published: May 2003

Little is known about changes in the composition of dead wood jams along rivers and the possible consequences of any such changes on the river ecosystem. Although tree zonation along the upstream‐to‐downstream continuum is weak and highly variable from a system to another, a clear transition appears in the piedmont zone, which is reflected by transitions in dead wood sources as well as for dead wood transport, storage and decomposition processes. In this paper, we focus on large lowland rivers of southwestern France, where riparian vegetation is increasingly fragmented, reduced in area and/or is entirely replaced by planted forests (poplar plantations). The amount and the potential role of dead wood is practically unknown in these rivers. One reason is that French legislation obliges landowners and public service managers to remove all material from the stream in order to maintain unobstructed river flows. The other reason is that unlike pristine streams in northern regions, these rivers have been regulated for several decades (Adour River) or even for several centuries (Garonne River). The vegetation component of the managed riparian landscape has changed in particular as a result of i) a decrease in stream dynamics, ii) the replacement of natural forests by planted ones, and iii) the invasion of natural communities by introduced woody species.

The possible consequences of biological invasions on the role of dead wood jams are discussed in light of: i) a local study of wood jams along a moderately modified system; ii) changes observed in the composition of trees along the Adour River over the past 10 years; iii) a regional case study involving two chosen species. Whereas white willow populations are declining along streams in southwestern France, the box‐elder, introduced from the United States, has spread extensively in the last two decades. Statistical models would suggest that competitive pressures are limited between these two species, boxelder is expected to replace white willow in the near future as a consequence of an increase in river regulation and global warming. This can be expected to have important consequences on dead wood dynamics, and on the management of woody debris, especially since trends indicate a replacement of softwood species by hardwood species. Copyright © 2003 John Wiley & Sons, Ltd.
Two GTPs are consumed on EF‐Tu per peptide bond in poly(Phe) synthesis, in spite of switching stoichiometry of the EF‐Tu·aminoacyl‐tRNA complex with temperature
Authors: Dinçbaş Vildan , Bilgin Neş'e , Scoble Judith , Ehrenberg Måns
Published: May 2003

Recent observations indicate that the stoichiometry for the complex between EF‐Tu · GTP and aminoacyl‐tRNA (aa‐tRNA) changes with temperature. At 37°C two EF‐Tu · GTPs bind one aa‐tRNA in an extended ternary complex, but at 0°C the complex has 1:1 stoichiometry. However, the present experiments show that there are two GTPs hydrolyzed on EF‐Tu per peptide bond in poly(Phe) synthesis at 37°C as well as at 0°C. This indicates two different pathways for the enzymatic binding of aa‐tRNA to the A‐site on the ribosome.
Pilins of fimbrial adhesins of different member species of enterobacteriaceae are structurally similar to the C‐terminal half of adhesin proteins
Authors: Girardeau Jean-Pierre , Bertin Yolande
Published: May 2003

The structural relatedness of pilins and the C‐terminal half of adhesin proteins in different member species of Enterobacteriaceae was deduced from their two‐dimensional sequence analysis using the hydrophobic cluster analysis (HCA) and secondary structure predictions from the profile network Hei‐Delberg program (PHD). Despite a large evolutionary distance between the two protein families, we show that pilins and the C‐terminal domain of adhesins have a similar folding that can serve as modules for pilus assembly.
Stability and immunological reactivity of recombinant membrane CD4 electroinserted into the plasma membrane of erythrocytes
Authors: Hannig Jürgen , Dawkins Cynthia , Tosi Pierre-François , Nicolau Claude
Published: May 2003

Concentration‐dependent electroinsertion of recombinant human membrane CD4 in human erythrocytes shows a saturation at an average of about 3,500 inserted CD4 epitopes per cell, detectable by flow cytometry. The erythrocyte recovery drops to 10% at this high level of electroinsertion. Experimentally an optimum for cell recovery and insertion rate was found at about 2,500 CD4 epitopes per red blood cell. In vitro stability assays by flow cytometry indicated a temperature‐ and medium‐dependent decrease in the number of CD4 epitopes inserted per cell. This decrease is biphasic, with an exponential part during the first 24 h after electroinsertion followed by a much slower linear decay.
Novel synthetic retinoic acid inhibits rat collagen arthritis and differentially affects serum immunoglobulin subclass levels
Authors: Kuwabara Kenji , Shudo Koichi , Hori Yozo
Published: May 2003

Retinoids affect many biological processes such as cell proliferation, differentiation and morphogenesis, but their effects on arthritic patients and animal models of arthritis are controversial. We tested the effect of a novel synthetic retinoic acid, Am‐80 (4‐1(5,6,7,8‐tetrahydro‐5,5,8,8,‐tetramethyl‐2‐naphthalenyl) carbamoyl] benzoic acid), on type‐II collagen (CII)‐induced arthritis (CIA) in rats. Am‐80 markedly suppressed the incidence of arthritis, hindpaw swelling and bone destruction. In contrast, 13‐cisretinoic acid (13‐cis‐RA) hardly inhibited these CIA symptoms. Moreover, Am‐80, but not 13‐cis‐RA, strongly reduced the serum level of anti‐CII antibody and differentially affected the levels of immunoglobulin (Ig) subclasses in vivo: IgG1 and IgG2a levels were decreased, while IgA level was increased without any change in the IgM level. These findings indicate that Am‐80 may be one of the lead retinoic acids of a new class of anti‐inflammatory agents.
Molecular characterization of a cDNA encoding functional human deoxyhypusine synthase and chromosomal mapping of the corresponding gene locus
Authors: Bevec Dorian , Kappel Barbara , Jaksche Herbert , Csonga Robert , Hauber Joachim , Klier Hannelore , Steinkasserer Alexander
Published: May 2003

Deoxyhypusine synthase is essentially required for the post‐translational formation of hypusine, a modification of a specific lysine residue in eukaryotic initiation factor 5A, which appears to be pivotal for cell proliferation. From a human peripheral blood mononuclear cells cDNA library we isolated two independent sequences encoding biologically active deoxyhypusine synthase. DNA sequence analysis revealed a 369 amino acid protein with a molecular mass of 41.055 kDa. This recombinant deoxyhypusine synthase showed significant catalytic activity in synthesis of deoxyhypusine after in vitro transcription and translation as well as upon expression in Escherichia coli. Using a panel of somatic rodent‐human cell hybrids we localized the deoxyhupusine synthase gene to human chromosome 19.
Metabolic efficiency of liver mitochondria in rats with decreased thermogenesis
Authors: Iossa Susanna , Mollica Maria Pia , Lionetti Lillà , Crescenzo Raffaella , Botta Monica , Liverini Giovanna
Published: May 2003

We have studied changes in hepatic mitochondrial efficiency induced by 24‐h fasting or acclimation at 29°C, two conditions of reduced thermogenesis. Basal and palmitate‐induced proton leak, which contribute to mitochondrial efficiency, are not affected after 24‐h fasting, when serum free triiodothyronine decreases significantly and serum free fatty acids increase significantly. In rats at 29°C, in which serum free triiodothyronine and fatty acids decrease significantly, basal proton leak increases significantly, while no variation is found in palmitate‐induced proton leak. The present results indicate that mitochondrial efficiency in the liver is not related to a physiological decrease in whole body thermogenesis.
Identification and characterization of plant agmatine iminohydrolase, the last missing link in polyamine biosynthesis of plants
Authors: Janowitz Tim , Kneifel Helmut , Piotrowski Markus
Published: May 2003

The cloning, expression and characterization of plant agmatine iminohydrolase (AIH, also known as agmatine deiminase, EC 3.5.3.12) is described. Recombinant AIH of Arabidopsis thaliana forms dimers and catalyzes the specific conversion of agmatine to N‐carbamoylputrescine and ammonia. Biochemical data suggested that cysteine side chains are involved in catalysis. However, site‐directed mutagenesis of the two highly conserved cysteine residues of AIH showed that these cysteines are important but not essential for activity, arguing against a thioester substrate–enzyme intermediate during catalysis. This work represents the completion of the cloning of the arginine decarboxylase pathway genes of higher plants.
Little Ice Age subsidence and post Little Ice Age uplift at Juneau, Alaska, inferred from dendrochronology and geomorphology
Authors: Motyka Roman J.
Published: May 2003

Application of dendrochronology and geomorphology to a recently emerged coastal area near Juneau, Alaska, has documented a Little Ice Age (LIA) sea-level transgression to 6.2 m above current sea level. The rise in relative sea level is attributed to regional subsidence and appears to have stabilized by the mid 16th century, based on a sea-cliff eroded into late-Pleistocene glaciomarine sediments. Land began emerging between A.D. 1770 and 1790, coincident with retreat of regional glaciers from their LIA maximums. This emergence has continued since then, paralleling regional glacier retreat. Total Juneau uplift since the late 18th century is estimated to be 3.2 m. The rate of downward colonization of newly emergent coastline by Sitka spruce during the 20th century closely parallels the rate of sea-level fall documented by analysis of local tide-gauge records (1.3 cm/yr). Regional and Glacier Bay LIA loading and unloading are inferred to be the primary mechanisms driving subsidence and uplift in the Juneau area. Climate change rather then regional tectonics has forced relative sea-level change over the last several hundred years.