bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi‐channel long‐distance optical fiber transmission using dispersion‐induced microwave transmission windows
Authors: Gutiérrez‐Martínez C. , Mollier P. , Porte H. , Zaldívar‐Huerta I. , Carcaño‐Rivera L. , Goedgebuer J. P. 
Published: January 2003

AbstractIn this paper, the model and implementation of an optical transmission system using a multi‐longitudinal mode optical source and a dispersive optical channel are described. Such a system exhibits multi‐bandpass transmission windows, as a result of a combination of the wideband optical spectrum and chromatic dispersion on the optical channel. As shown in this paper, the band‐pass windows are centered at frequencies that depend on the spectral free range of the optical source and optical channel length. In the telecommunications domain, band‐pass transmission windows can be used for multiplexing analog and/or digital signals, as an alternative way for transmitting baseband and modulated subcarriers, through optical‐fiber links. To show such a potential application, the multiplexed transmission of two microwave signals, using two adjacent band‐pass windows, is also described in this paper. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 202–206, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10720
A low‐phase‐noise local oscillator for a Ka‐band satellite transponder
Authors: Ryu Keun‐Kwan , Lee Moon‐Que , Yom In‐Bok , Lee Seong‐Pal 
Published: January 2003

AbstractA low‐phase‐noise local oscillator (LO) is developed for a Ka‐band satellite transponder. A novel dielectric resonator‐voltage controlled oscillator (DR‐VCO) is also designed by using a high‐impedance inverter coupled with a dielectric resonator to improve the phase‐noise performance out of the loop bandwidth. This LO performs the harmonic suppression characteristics above 43.83 dBc and requires 2.6‐watt power consumption. The phase‐noise characteristics are exhibited as −102.5 dBc/Hz at 10‐KHz offset frequency and −104.0 dBc/Hz at 100‐KHz offset frequency, respectively, with output power of 13.50 dBm ± 0.33 dB over a temperature range of −20 ∼ +70°C. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 216–218, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10724
A simple and accurate expression for the bandwidth of electrically thick rectangular microstrip antennas
Authors: Guney K. 
Published: January 2003

AbstractA new, very simple closed‐form expression for computing the bandwidth of rectangular microstrip antennas with thick substrates is presented. It is obtained by means of a curve‐fitting technique, and is useful for the computer‐aided design of microstrip antennas. The theoretical bandwidth results obtained by using this new bandwidth expression are in very good agreement with the experimental results reported elsewhere. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 225–228, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10727
Stress intensity factor analysis of interface cracks using X‐FEM
Authors: Nagashima Toshio , Omoto Youhei , Tani Shuichi 
Published: January 2003

AbstractThe extended finite element method (X‐FEM) proposed by Belytschko et al. (International Journal for Numerical Methods in Engineering 1999; 45: 602; 1999; 46: 131; 2001; 50: 993) uses interpolation functions based on the concept of partition of unity, and considers the asymptotic solution and the discontinuity of displacement fields near a crack independently of the finite element mesh. This paper describes the application of X‐FEM to stress analyses of structures containing interface cracks between dissimilar materials. In X‐FEM, an interface crack can be modelled by locally changing an interpolation function in the element near a crack. The energy release rate should be separated into individual stress intensity factors, K1 and K2, because the stress field around the interface crack has mixed modes coupled with mode‐I and mode‐II. For this purpose, various evaluation methods used in conjunction with numerical methods such as FEM and BEM are reviewed. These methods are examined in numerical examples of elastostatic analyses of structures containing interface cracks using X‐FEM. The numerical results show that X‐FEM is an effective method for performing stress analyses and evaluating stress intensity factors in problems related to bi‐material fractures. Copyright © 2003 John Wiley & Sons, Ltd.
Optimization of thermo‐elasto‐plastic processes using Eulerian sensitivity analysis
Authors: Paul S. , Michaleris P. , Shanghvi J. Y. 
Published: January 2003

AbstractA computational scheme for the analysis and optimization of quasi‐static thermo‐mechanical processes is presented in this paper. In order to obtain desirable mechanical transformations in a workpiece using a thermal treatment process, the optimal control parameters need to be determined. The problem is addressed by posing the process as a decoupled thermo‐mechanical finite element problem and performing an optimization using gradient methods. The forward problem is solved using the Eulerian formulation since it is computationally more efficient compared to an equivalent Lagrangian formulation. The design sensitivities required for the optimization are developed analytically using direct differentiation. This systematic design approach is applied to optimize a laser forming process. The objective is to maximize the angular distortion of a specimen subject to the constraint that the phase transition temperature is not exceeded at any point in the model. Copyright © 2003 John Wiley & Sons, Ltd.
Healing of adsorbed polymer layers in a narrow gap following removal by shear
Authors: Raviv Uri , Klein Jacob 
Published: January 2003

AbstractThe shear and normal forces between layers of poly(ethylene oxide) (PEO), of molecular weights Mw = 37 kg/mol adsorbed onto smooth, curved solid (mica) surfaces across the good solvent toluene have been determined using a surface force balance (SFB). The equilibrium Fn(D) profiles are closely similar to those measured in earlier studies between adsorbed PEO layers. The shearing motion causes the removal of polymer from within the intersurface gap during sliding. The recovery of the adsorbing layer has been measured and the amount of adsorption with time was calculated. Our findings showed that there is no migration of polymers on the surfaces and that the recovery of the layer is controlled by the rate of diffusion of polymer chains into the gap. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of the structure of the polymer matrix on the terthiophene chromophore dispersion in dichroic polyethelene films
Authors: Pucci Andrea , Ruggeri Giacomo , Moretto Letizia , Bronco Simona 
Published: January 2003

AbstractIn the frame of an ongoing research project dealing with linear optical polarizers produced by dispersing terthiophene derivatives in ultra‐high‐molecular‐weight polyethylene (UHMWPE) and successive orientation by uniaxial stretching of the derived films, the present paper describes the use of linear‐low‐density polyethylene (LLDPE) or high‐density polyethylene (HDPE) as an alternative polymer matrix in relation also to the possibility of taking different preparation routes. The study was performed with the easily prepared 5,5″‐bis‐thiooctadecyl‐2,2′:5′,2″‐terthiophene as the chromophore which was blended in a Brabender mixer at 180 °C and concentration 0.2–2% w/w with LLDPE or HDPE in the bulk. The morphology and optical properties of the films obtained by compression moulding were compared with those of a similar film in UHMWPE prepared by solution casting. Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) analysis of the unoriented films of the former type were also performed. These data suggest the improved dispersion of the chromophore in case of the films obtained by melt processing. After uniaxial stretching up to 14–30 times the original length, molecular orientation was evaluated in different cases by measuring the dichroic ratio [R = A∥/A⟂] and the order parameter [S = (R − 1)/(R + 2)]. Also the polarizer performance was detected by comparing the dependence of polarizing efficiency on single‐piece transmittance of the different samples. Copyright © 2003 John Wiley & Sons, Ltd.
A model for the future conduct of pharmacovigilance
Authors: Waller Patrick C. , Evans Stephen J. W. 
Published: January 2003

AbstractA scientific model to support excellence in pharmacovigilance has been developed from first principles by brainstorming sessions and discussions with experts in the field. The model represents a long‐term vision of how pharmacovigilance could be conducted in the future. So far it has been developed without any consideration of constraints such as resources or the need for legislative change. Although the vision is holistic, it would be possible to test and implement parts of the model in a piecemeal fashion. Copyright © 2002 John Wiley & Sons, Ltd.
Prolongation of the QT interval and cardiac arrhythmias associated with cisapride: limitations of the pharmacoepidemiological studies conducted and proposals for the future
Authors: Layton Deborah , Key Cheryl , Shakir Saad A. W. 
Published: January 2003

AbstractNot all hazards can be identified from clinical studies prior to marketing of medicinal products. Pre‐marketing large‐scale trials for cisapride did not report any serious cardiac arrhythmias. After a long period of availability in several countries it was withdrawn in 2000 because of reports of serious, and in many cases fatal, cardiac events. Whilst spontaneous reporting systems for adverse drug reactions (ADRs) have limitations such as under‐reporting, they are an effective system for signal generation, particularly of rare ADRs. Pharmacoepidemiological studies aim to identify and calculate the incidence of adverse reactions, with increased sensitivity to less common ADRs compared to randomised controlled trials, yet cohort sizes may be insufficient to detect very rare ADRs such as drug‐induced Torsade de Pointes, with an estimated incidence of the order of 1 per 12 000 to 1 per 120 000 patients. Several pharmacoepidemiological studies investigated adverse events associated with cisapride, one of which specifically examined the association between serious cardiac arrhythmias and cisapride. These observational studies were conducted using large population databases, but each failed to identify sufficient cases to establish a causal relationship. Explanations include that the cohort sample sizes were too small, and either under‐, or mis‐reporting of events of interest may have occurred. To estimate the risk of very rare adverse events, pharmacoepidemiological studies require very large numbers. Furthermore, the events in question need to be clinically recognisable by doctors and adequately documented in patients' notes, computer records, or on study questionnaires. The establishment of a national registry for drug‐induced QT prolongation to identify cases and correlate clinical information may help to better identify these rare ADRs earlier. Such proactive surveillance could avoid unnecessary delays for other drugs where QT prolongation and serious cardiac arrhythmias may be an issue. Copyright © 2002 John Wiley & Sons, Ltd.
Comparing patterns of long‐term benzodiazepine use between a Dutch and a Swedish community
Authors: van Hulten Rolf , Isacson Dag , Bakker Albert , Leufkens Hubert G. 
Published: January 2003

AbstractBackgroundThere is much concern about the widespread long‐term use of benzodiazepines. Utilisation data can give a foundation for interventions for appropriate use.ObjectiveTo compare long‐term usage patterns of benzodiazepines in a Dutch and a Swedish community in different periods.MethodsEight‐year follow‐up patterns of use were investigated with respect to the characteristics of those who continued use over the whole follow‐up period. In the Dutch community of 13 500, the data of a cohort of 1358 benzodiazepine users were analysed during the years 1984–1991; in the Swedish community of 20 000 people, a cohort of 2038 benzodiazepine users was followed from 1976.ResultsAt the end of the follow‐up period, 32.9% of the Dutch cohort and 33% of the Swedish cohort had continued use of benzodiazepines. The two overall survival curves showed similar patterns. Stratification for age, gender, previous versus initial use and heavy versus non‐heavy use showed comparable proportions of patients continuing benzodiazepine use over time.ConclusionThe parallels in the results of two cohorts in different countries and different periods are striking and give support to the idea to stimulate interventions to reduce long‐term benzodiazepine use. Copyright © 2002 John Wiley & Sons, Ltd.
Molecular cloning and expression of a variant form of hippostasin/KLK11 in prostate
Authors: Nakamura Terukazu , Mitsui Shinichi , Okui Akira , Miki Tsuneharu , Yamaguchi Nozomi 
Published: January 2003

AbstractBackgroundHippostasin is a kallikrein‐like serine protease, which has two alternatively spliced isoforms, brain‐type and prostate‐type. We previously reported alternative expression of hippostasin in prostate cancer cell lines.MethodsWe studied the expression of a variant‐form hippostasin (isoform 3) mRNA by RT‐PCR. Localization of the isoform 3 protein was examined by immunohistochemistry. The enzymatic activity of the recombinant protein was measured with synthetic substrates.ResultsA novel isoform of hippostasin contains 25 additional amino acids in the catalytic triad of brain‐type hippostasin. Its mRNA was expressed in normal prostate tissue, BPH, and prostate cancer cell lines. The protein was localized in the prostate secretory epithelium. The enzyme activity was similar to that of brain‐type hippostasin, which has kallikrein‐like activity.ConclusionsIn this study, we have identified a third isoform of hippostasin, which was designated variant‐form (isoform 3). Hippostasin isoform 3 may play a role in the prostate, including reproductive and/or tumorigenic functions. Prostate 54: 299–305, 2003. © 2003 Wiley‐Liss, Inc.
Selective reduction of AKR1C2 in prostate cancer and its role in DHT metabolism
Authors: Ji Qing , Chang Lilly , VanDenBerg David , Stanczyk Frank Z. , Stolz Andrew 
Published: January 2003

AbstractBACKGROUNDAs androgens play an essential role in prostate cancer, we sought to develop a real‐time PCR to characterize mRNA expression profiles of human members of the Aldo‐Keto Reductase (AKR) 1C gene family, as well as of 5α‐steroid reductase Type II (SRD5A2) in prostate cancer samples. Functional activity and regulation of AKR1C2, a 3α‐hydroxysteroid dehydrogenase (HSD) type III, was also assessed in prostate cancer cell lines.METHODSGene specific PCR primers were established and relative gene expression of human AKR1C family members was determined in paired samples of cancerous and surrounding unaffected prostate tissue.RESULTSAKR1C2 preferentially reduces DHT to the weak metabolite 5α‐androstane‐3α,17β‐diol (3α‐diol) without conversion of 3α‐diol to DHT in the PC‐3 cell line, and its expression was increased by DHT treatment in LNCaP cells. Selectively reduced expression of AKR1C2 mRNA, but not AKR1C1 (97% sequence identity), was found in approximately half of the pairs whereas AKR1C3 relative expression was not significantly altered. No aberrant expression of AKR1C4 expression or significant differences in SRD5A2 gene expression were found.CONCLUSIONSAKR1C2 functions as a DHT reductase in prostate‐derived cells lines and is regulated by DHT. Additional studies are needed to further define the significance of reduced AKR1C2 expression in prostate cancer and its potential role in modulating local availability of DHT. Prostate 54: 275–289, 2003. © 2003 Wiley‐Liss, Inc.
Leptomycin B stabilizes and activates p53 in primary prostatic epithelial cells and induces apoptosis in the LNCaP cell line
Authors: Lecane Philip S. , Kiviharju Taija M. , Sellers Robert G. , Peehl Donna M. 
Published: January 2003

AbstractBackgroundPrevious studies showed that primary cultures of normal and malignant human prostatic epithelial cells are defective in their ability to upregulate the tumor suppressor protein p53 in response to DNA damage. This dysfunctional regulation of p53 may be relevant to both the high incidence of prostate cancer and its resistance to chemotherapy. Leptomycin B (LMB) has recently been found to increase the protein level and transcriptional activity of p53 by interfering with nucleocytoplasmic export and subsequent degradation by the proteasome. We investigated the ability of LMB to activate p53 in prostatic epithelial cells.MethodsPrimary cultures and the cell lines LNCaP and DU 145 were treated with LMB. p53 protein was evaluated in Western blots and by immunocytochemistry. Induction of downstream targets of p53 was evaluated in Western and Northern blots. Growth inhibition, cell cycle arrest, and apoptosis in response to LMB were measured in clonal growth assays, by flow cytometry, and by Hoescht/propidium iodide staining, respectively.ResultsTreatment of prostatic epithelial cells with LMB led to post‐translational stabilization of p53, activation of downstream target genes, and induction of cell cycle arrest in primary cultures and apoptosis in LNCaP (with wild‐type p53) but not DU 145 (with mutant p53) cells.Conclusionsp53 in primary cultures of normal and malignant prostate cells, although dysfunctional in that it is not responsive to DNA damage, is activated by LMB. The ability of LMB to stabilize p53 and induce expression of p53‐responsive growth inhibitory genes may be a useful lead in the development of chemopreventive or therapeutic small molecules that can modulate p53 function in prostatic epithelial cells. Prostate 54: 258–267, 2003. © 2003 Wiley‐Liss, Inc.
Repair of impurity‐poisoned protein crystal surfaces
Authors: Plomp M. , McPherson A. , Malkin A.J. 
Published: January 2003

AbstractThe surface morphology of Bence–Jones protein (BJP) crystals was investigated during growth and dissolution by using in situ atomic force microscopy (AFM). It was shown that over a wide supersaturation range, impurities adsorb on the crystalline surface and ultimately form an impurity adsorption layer that prevents further growth of the crystal. At low undersaturations, this impurity adsorption layer prevents dissolution. At greater undersaturation, dissolution takes place around large particles incorporated into the crystal, leading to etch pits with impurity‐free bottoms. On restoration of supersaturation conditions, two‐dimensional nucleation takes place on the impurity‐free bottoms of these etch pits. After new growth layers fill in the etch pits, they cover the impurity‐poisoned top layer of the crystal face. This leads to the resumption of its growth. Formation of an impurity‐adsorption layer can explain the termination of growth of macromolecular crystals that has been widely noted. Growth‐dissolution‐growth cycles could be used to produce larger crystals that otherwise would have stopped growing because of impurity poisoning. Proteins 2003;50:486–495. © 2003 Wiley‐Liss, Inc.
Alpha helix shortening in 1522 MSP‐1 conserved peptide analogs is associated with immunogenicity and protection against P. falciparum malaria
Authors: Cubillos Marcia , Espejo Fabiola , Purmova Jindra , Martinez Juan C. , Patarroyo M.E. 
Published: January 2003

Abstract1522 is a nonimmunogenic conserved high‐activity binding peptide (HABP) belonging to Plasmodium falciparum MSP‐1 protein N‐terminal fragment. The key amino acids in binding to red blood cells (RBC) were identified and replaced by others having similar mass but different charge. Because conserved HABPs are not antigenic nor immunogenic, immunogenicity and protectivity studies were then conducted on them in the Aotus monkey. 1H‐NMR studies included the lead peptide 1522 as well as the analogs 9782, 13446, 13448, and 13442 to relate their structure to biological function. All the peptides presented α‐helical structure, with differences observed in helix location and extension. The nonprotective 1522 peptide was totally helical from the N‐ to the C‐terminus, very similar to nonprotective 13442 and 13448 peptides whose extension was almost totally helical. The 9782 and 13446 protective peptides, however, possessed a shorter helical region where modified critical binding residues were not included. A more flexible region was generated at the C‐terminus in those peptides with a shorter helical region, leading to a greater number of conformers. These data suggest that peptide flexibility results in increased interaction with immune system molecules, generating protective immunity. Proteins 2003;50:400–409. © 2003 Wiley‐Liss, Inc.
Structural studies on MtRecA‐nucleotide complexes: Insights into DNA and nucleotide binding and the structural signature of NTP recognition
Authors: Datta S. , Ganesh N. , Chandra Nagasuma R. , Muniyappa K. , Vijayan M. 
Published: January 2003

AbstractRecA protein plays a crucial role in homologous recombination and repair of DNA. Central to all activities of RecA is its binding to Mg+2‐ATP. The active form of the protein is a helical nucleoprotein filament containing the nucleotide cofactor and single‐stranded DNA. The stability and structure of the helical nucleoprotein filament formed by RecA are modulated by nucleotide cofactors. Here we report crystal structures of a MtRecA‐ADP complex, complexes with ATPγS in the presence and absence of magnesium as well as a complex with dATP and Mg+2. Comparison with the recently solved crystal structures of the apo form as well as a complex with ADP‐AlF4 confirms an expansion of the P‐loop region in MtRecA, compared to its homologue in Escherichia coli, correlating with the reduced affinity of MtRecA for ATP. The ligand bound structures reveal subtle variations in nucleotide conformations among different nucleotides that serve in maintaining the network of interactions crucial for nucleotide binding. The nucleotide binding site itself, however, remains relatively unchanged. The analysis also reveals that ATPγS rather than ADP‐AlF4 is structurally a better mimic of ATP. From among the complexed structures, a definition for the two DNA‐binding loops L1 and L2 has clearly emerged for the first time and provides a basis to understand DNA binding by RecA. The structural information obtained from these complexes correlates well with the extensive biochemical data on mutants available in the literature, contributing to an understanding of the role of individual residues in the nucleotide binding pocket, at the molecular level. Modeling studies on the mutants again point to the relative rigidity of the nucleotide binding site. Comparison with other NTP binding proteins reveals many commonalties in modes of binding by diverse members in the structural family, contributing to our understanding of the structural signature of NTP recognition. Proteins 2003;50:474–485. © 2003 Wiley‐Liss, Inc.
Matrix‐assisted laser desorption/ionization study of cationization of PEO‐PPP rod‐coil diblock polymers
Authors: Chen Hui , He Meiyu , Wan Xinhua , Yang Lifang , He Haifeng 
Published: January 2003

AbstractFive PEO‐PPP rod‐coil diblock polymers were synthesized and characterized using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). By using a series of alkali chlorides as cation salts, relative cation affinities were studied. Different cation affinities and shifts in molecular weight distributions were found as a result of changing the cation type and size. Also, a study of lithium cationization resulted in determination of a recommended quantity of lithium to be used. Copyright © 2002 John Wiley & Sons, Ltd.