bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of single‐walled carbon nanotubes on the crystallization behavior of polypropylene
Authors: Valentini L. , Biagiotti J. , Kenny J. M. , Santucci S. 
Published: November 2002

AbstractPolypropylene matrix composites reinforced with single‐walled carbon nanotubes (SWNTs) were produced with different nanotube concentrations. The characterization of these new materials was performed by differential scanning calorimetry and Raman and Fourier transform infrared spectroscopy to obtain information on the matrix–nanotube interaction, on the crystallization kinetics of polypropylene, and especially on the macrostructure and organization of the nanotubes in the composite. On the one hand, the results confirmed the expected nucleant effect of nanotubes on the crystallization of polypropylene, but on the other hand, this effect was not linearly dependent on the SWNT content: there was a saturation of the nucleant effect at low nanotube concentrations. Raman spectroscopy was successfully applied to demonstrating that in the composite films, the crystallization kinetics were strongly affected by the distance between the nanotube bundles as a result of a different intercalation of the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 708–713, 2003
Lateral variation within a hiatal‐condensed bed and the controls on the formation and occurrence of berthierine ooids: a case study from the Middle Jurassic of NE England, UK
Authors: Williams M.E. 
Published: November 2002

AbstractShallow‐marine sandstone and berthierinic, ooidal, sandy limestone form the Hackness Rock Member (HRM), a Callovian‐age hiatal‐condensed bed in NE England. The HRM was deposited in response to a rise in relative sea‐level. Apart from the major hiatal surfaces represented by two significant non‐sequences, it contains a number of other hiatal surfaces representing shorter periods of time. Although the HRM has its own distinctive bioclastic concentrations, early diagenetic mineral assemblages and specific types and degrees of bioturbation, the expression of this bed is variable even over short distances.Variations in the topography of the sea floor produced local hollows and highs, which account for the lateral variability of the HRM and controlled where berthierine ooids formed. Hollows created ‘clastic/colloidal’ traps where finer‐grained sediment accumulated and had low physical mobility; these conditions favoured intra‐sedimentary growth of berthierine ooids in an early (sub‐oxic) diagenetic environment. In contrast, highs were more susceptible to storm reworking and material was more mobile; these conditions resulted in a lower overall rate of accumulation and a lower degree of shallow, sub‐surface diagenesis. Copyright © 2002 John Wiley & Sons, Ltd.
Role of human heme oxygenase‐1 in attenuating TNF‐α‐mediated inflammation injury in endothelial cells
Authors: Kushida Taketoshi , Volti Giovanni Li , Quan Shuo , Goodman Alvin , Abraham Nader G. 
Published: November 2002

AbstractHeme oxygenase (HO) is the rate‐limiting enzyme in the formation of bilirubin, an antioxidant, and carbon monoxide (CO), a cell cycle modulator and a vasodilator. Cyclooxygenase (COX) is a hemeprotein that catalyzes the conversion of arachidonic acid (AA) to various prostanoids, which play an important role in the regulation of vascular endothelial function in normal and disease states. The influence of suppression or overexpression of HO isoforms on COX expression and synthesis of prostanoids is of considerable physiological importance. Consequently, the goal of the present study was to determine whether the heme‐HO system regulates COX enzyme expression and activity in vascular endothelial cells in the absence and presence of TNF‐α (100 ng/ml). Endothelial cells stably transfected with the retrovirus containing the human HO‐1 gene exhibited a several‐fold increase in HO‐1 protein levels, which was accompanied by an increase in HO activity and a marked decrease in PGE2 and 6‐keto PGF1α levels. We also assessed the effect of retrovirus‐mediated HO‐1 gene transfer in the sense and antisense orientation on HO‐1 expression and cell cycle progression in human endothelial cells. The levels of CO and HO activity were increased in cells transduced with the HO‐1 sense and were greatly suppressed in cells transduced with HO‐1 antisense as compared to control sham‐transduced cells (P < 0.05). The percentage of the G1‐phase in cells transduced with HO‐1 significantly increased (41.4% ± 9.1) compared with control endothelial cells (34.8% ± 4.9). We measured COX activity by determining the levels of PGI2 and PGE2. The levels of PGI2 decreased in cells transduced with HO‐1 sense and increased in cells transduced with HO‐1 in antisense orientation. The expression of p27 was also studied and showed a marked decrease in cells transduced with HO‐1 sense and a marked increase in the HO‐1 antisense transduced cells. Cell cycle analysis of endothelial cell DNA distributions indicated that the TNF‐α‐induced decrease in the proportion of G1‐phase cells and increase in apoptotic cells in control cultures could be abrogated by transfection with HO‐1 in the sense orientation. Tin mesoporphyrin (SnMP) reversed the protective effect of HO‐1. These results demonstrate that overexpressing HO‐1 mitigated the TNF‐α‐mediated changes in cell cycle progression and apoptosis, perhaps by a decrease in the levels of COX activity. J. Cell. Biochem. 87: 377–385, 2002. © 2002 Wiley‐Liss, Inc.
Anchorage‐independent phosphorylation of p130Cas protects lung adenocarcinoma cells from anoikis
Authors: Wei Lin , Yang Yu , Zhang Xin , Yu Qiang 
Published: November 2002

AbstractThe regulation and function of the signaling adaptor protein p130Cas in tumor cell anchorage‐independent survival, or anoikis resistance, were investigated in human lung adenocarcinoma cells. The tyrosine phosphorylation and function of p130Cas during cell detachment were analyzed in tumor cells and compared with that of normal epithelial cells. Cell detachment trigged rapid dephosphorylation of p130Cas in the nontumorigenic and anoikis‐sensitive normal epithelial cells, but had no effect on the tyrosine phosphorylation of p130Cas in the anoikis‐resistant lung adenocarcinoma cells. Further analysis revealed that the total tyrosine kinase activities associated with p130Cas in the lung tumor cells are anchorage‐independent and are significantly higher than that in the normal cells, in which the p130Cas‐associated tyrosine kinase activities are anchorage‐dependent. Analysis of two known p130Cas‐associated tyrosine kinases FAK and Src indicated that the regulation of tyrosine phosphorylation of FAK and Src are altered in the tumor cells. Inhibition of Src specifically abolished phosphorylation of p130Cas and induced anoikis. Furthermore, overexpression of dominant‐negative forms of p130Cas also induced apoptosis. Taken together, these data suggest that p130Cas mediates a cell survival signal from cell–matrix interaction. Alterations in tumor cells that lead to constitutive phosphorylation of p130Cas can prevent cells from anoikis, hence contribute to tumor cell anchorage independence and metastasis. J. Cell. Biochem. 87: 439–449, 2002. © 2002 Wiley‐Liss, Inc.
Structurally adaptive hot spots at a protein interaction interface on TRAF3
Authors: Ely Kathryn R. , Li Chenglong 
Published: November 2002

AbstractTumor necrosis factor (TNF) signaling is controlled by receptors and intracellular signaling pathways that activate the NF‐κB transcription factor. The resulting signals elicit immune responses and have important implications for disorders such as autoimmunity or allergic reactions. TNF‐receptor‐associated factors (TRAFs) bind to the cytoplasmic portion of TNFRs as well as downstream regulators and thus are co‐inducers of the signal transduction. TRAF3 binds to diverse receptors and regulators by accomodating a conserved motif that is embedded in completely different structural frameworks. Thus, the protein–protein contact region on TRAF3 represents a binding interface that is structurally and functionally adaptive. In this report, three ‘hot spots’ at the TRAF3 protein–interaction interface are defined that provide the principal contact regions for different binding partners. The side‐chains of residues at these ‘hot spots’ are flexible and undergo movements on binding the different partners. These side chain rearrangements provide a structural adaptability that promotes interaction with a variety of distinct proteins. It is proposed that similar adaptive ‘hot spots’ are also present on the binding surfaces of TRAF1, TRAF2 and TRAF5. Copyright © 2002 John Wiley & Sons, Ltd.
Planar antenna array design with a multi‐purpose GA‐based procedure
Authors: Caorsi Salvatore , Lommi Andrea , Massa Andrea , Piffer Stefano , Trucco Andrea 
Published: November 2002

AbstractThis paper deals with the synthesis of planar arrays. In the framework of iterative search procedures, a method based on a genetic algorithm (GA) is presented. Starting from the definition of a suitably defined cost function, thinning and weighting a randomly generated array configuration, the multi‐purpose stochastic procedure is able to satisfy various antenna constraints to determines an optimal trade‐off among contrasting requirements. In order to confirm the reliability of the proposed approach (also in comparison with the related literature), some highly optimized antenna array designs are reported and discussed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 428–430, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10629
Array beam scanning by element frequency tuning
Authors: Shafai L. , Daneshmand M. 
Published: November 2002

AbstractThe relationship between the resonance frequency of an antenna and the phase of its radiated field is established, indicating that the frequency or dimensional tuning may be used for beam scanning of the arrays. For microstrip patch antennas the range of far field phase variation within the element bandwidth is determined. Examples for limited beam scans of four element arrays are considered and studied. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 430–434, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10630
New CAD model to calculate the resonant frequency of inverted microstrip circular patch antennas
Authors: Guha Debatosh , Siddiqui Jawad Y. 
Published: November 2002

AbstractIn this paper, a new CAD model is proposed to calculate accurate resonant frequencies of inverted microstrip circular patch antennas having a wide range of parameters. This model incorporates all the effects of various dimensions and dielectrics used. Computed results for the first few modes are compared with some new measurements. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 434–437, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10631
Two‐arm microstrip spiral antenna with a circular aperture on the ground plane
Authors: Oh Daeyoung , Kim Myungki , Park Ikmo 
Published: November 2002

AbstractThis paper presents a two‐arm microstrip spiral antenna with a circular aperture on the ground plane that produces either an axial beam or a tilted beam, depending on the operating frequency. A 50‐Ω microstrip feedline is divided into two 100‐Ω lines that feed the spiral antenna from the outer end of the spiral arms with a 180° phase difference at fo. The antenna is realized on a planar form without any balun circuit using a microstrip structure, which is easily compatible with millimeter‐ and microwave‐integrated circuits. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 453–455, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10636
Mutual impedance formula between patch antennas based on synthetic asymptote and variable separation
Authors: Sun Y. X. , Chow Y. L. , Fang D. G. 
Published: November 2002

AbstractA formula for mutual impedance between patch antennas is constructed based on the physics of the static near field and the radiation far field of the couplings. This leads to asynthetic asymptoteform [1] of separated variables of the center‐to‐center distancerand the azimuth angle ϕ. Only 12 coefficients are to be determined by matching with a full‐wave analysis through commercial software, such as IE3D. Our formula is accurate and complete, with no restriction on the detailed structures of patch, feed, and substrate. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 466–470, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10640
Photonic band gap studies on periodic metallic structures in the microwave region
Authors: Tiwari Manoj K. , Gupta K. K. , Gupta H. C. , Dube D. C. 
Published: November 2002

AbstractWe present our experimental findings on microstrip‐type metallic photonic band gap (PBG) periodic structures prepared using a commercial aluminum foil. Effect of change in geometry of the periodic dielectric structure, namely, period, rectangular hole length, and defect on PBG, is studied. It is found that as the rectangular‐hole‐cut dimension decreases in terms of length, the lower edge of the band gap decreases toward the lower frequency side of the microwave region. It is also observed that as the defect length increases, the band gap edge again shifts toward the lower frequency side. These findings of band gap with air as substrate confirm the role of wave impedance in purely metallic periodic structures. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 483–486, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10644
Influence of birefringence on soliton switching in a twin‐core fiber coupler
Authors: Li Hong , Huang Dexiu , Wang D. N. 
Published: November 2002

AbstractIn this paper, the effects of randomly varying birefringence on soliton switching in a twin‐core fiber coupler are discussed in detail by numerical simulation. The results obtained show that these effects on sub‐ps soliton switching cannot be neglected, they would degrade the quality of the coupler. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 502–506, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10649
Theoretical justification of empirical additivity schemes for conformational energies
Authors: Šatkovskienė D. 
Published: November 2002

AbstractAdditivity of conformational energy of saturated molecules has been studied using the perturbation theory for density matrix. Analytical expressions for both total and conformational energies have been obtained and analyzed up to the third‐order members. It is shown that the conformational energy of compounds under investigation can be presented as a sum of transferable increments corresponding to the energies of separate conformational segments and their sequences. The role of end groups in determination of energies of conformational segments is revealed. The influence of substitution has been investigated. The dependence of subtle conformational effects on common structural peculiarities of Hamiltonians of saturated molecules has been concluded. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Computation of two‐center Coulomb integrals over Slater‐type orbitals using elliptical coordinates
Authors: Özmen Ayhan , Karakaş Asli , Atav Ülfet , Yakar Yusuf 
Published: November 2002

AbstractA general analytic formula is obtained for the two‐center Coulomb integrals over Slater‐type orbitals in elliptical coordinates. Finite series expansions are used in the evaluation of the radial part of the integrals. The analytic formula is expressed in terms of a product of the well‐known auxiliary functions Ak(p) and Bk(p) and incomplete gamma functions. Recursive relations for the computer evaluation of these functions are given as well. The recursive relations are stable and our computer results are in good agreement with the benchmark values given in the literature. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Characterization of molecular complexity
Authors: Randić Milan , Plavs̆ić Dejan 
Published: November 2002

AbstractWe put forward a novel index of molecular complexity, ξ, taking into account the symmetry of a molecular graph and the specificity of structural components considered. The ξ index is defined as the sum of augmented valences of all mutually nonequivalent vertices in a molecular graph. The augmented valence of a vertex in a graph is the sum of its valence and valences of all neighboring vertices with the weight 1/2d depending on their distance, d, from the vertex. The ξ index is examined on the set of octane isomers and some special classes of graphs. It is also compared with a certain number of alternative complexity measures considered in the literature. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Automated test case generation for the stress testing of multimedia systems
Authors: Zhang Jian , Cheung S. C. 
Published: November 2002

AbstractWith the advancement in network bandwidth and computing power, multimedia systems have become a popular means for information delivery. However, general principles of system testing cannot be directly applied to testing of multimedia systems on account of their stringent temporal and synchronization requirements. In particular, few studies have been made on the stress testing of multimedia systems with respect to their temporal requirements under resource saturation. Stress testing is important because erroneous behavior is most likely to occur under resource saturation. This paper presents an automatable method of test case generation for the stress testing of multimedia systems. It adapts constraint solving techniques to generate test cases that lead to potential resource saturation in a multimedia system. Coverage of the test cases is defined upon the reachability graph of a multimedia system. The proposed stress testing technique is supported by tools and has been successfully applied to a real‐life commercial multimedia system. Although our technique focuses on the stress testing of multimedia systems, the underlying issues and concepts are applicable to other types of real‐time systems. Copyright © 2002 John Wiley & Sons, Ltd.
Lessons learned from automating tests for an operations support system
Authors: Fecko Mariusz A. , Lott Christopher M. 
Published: November 2002

AbstractWe present experience gained in automating tests for an operations support system. A major portion of the effort was devoted to extending a commercial test tool so that testers could easily manipulate graphical user interface (GUI) objects on two implementations of the application. For this purpose, we developed a test automation library as support infrastructure for writing tests. The challenges and tradeoffs are discussed such as simplicity/complexity for a tester versus a library developer, hiding/exposing window hierarchy to the tester, providing common methods for different types of GUI objects, transparently manipulating custom GUI widgets, and coping with data‐dependent test cases. We discuss the requirements of test code reusability, maintainability, and portability, and describe the solutions we found. In addition, we offer observations about benefits and pitfalls of test automation, our recommendations for maximizing return on investment, and results from automating a variety of tests. Copyright © 2002 John Wiley & Sons, Ltd.
Characterization of Two Noncellulosomal Subunits, ArfA and BgaA, from
Clostridium cellulovorans
That Cooperate with the Cellulosome in Plant Cell Wall Degradation
Authors: Kosugi Akihiko , Murashima Koichiro , Doi Roy H. 
Published: November 2002

ABSTRACT

Plant cell wall degradation by
Clostridium cellulovorans
requires the cooperative activity of its cellulases and hemicellulases. To characterize the α-
l
-arabinosidases that are involved in hemicellulose degradation, we screened the
C. cellulovorans
genomic library for clones with α-
l
-arabinofuranosidase or α-
l
-arabinopyranosidase activity, and two clones utilizing different substrates were isolated. The genes from the two clones,
arfA
and
bgaA
, encoded proteins of 493 and 659 amino acids with molecular weights of 55,731 and 76,414, respectively, and were located on neighboring loci. The amino acid sequences for ArfA and BgaA were related to α-
l
-arabinofuranosidase and β-galactosidase, respectively, which are classified as family 51 and family 42 glycosyl hydrolases, respectively. Recombinant ArfA (rArfA) had high activity for
p
-nitrophenyl α-
l
-arabinofuranoside, arabinoxylan, and arabinan but not for
p
-nitrophenyl α-
l
-arabinopyranoside. On the other hand, recombinant BgaA (rBgaA) hydrolyzed not only
p
-nitrophenyl α-
l
-arabinopyranoside but also
p
-nitrophenyl β-
d
-galactopyranoside. However, when the affinities of rBgaA for
p
-nitrophenyl α-
l
-arabinopyranoside and
p
-nitrophenyl β-
d
-galactopyranoside were compared, the

K
m

values were 1.51 and 6.06 mM, respectively, suggesting that BgaA possessed higher affinity for α-
l
-arabinopyranose residues than for β-
d
-galactopyranoside residues and possessed a novel enzymatic property for a family 42 β-galactosidase. Activity staining analyses revealed that ArfA and BgaA were located exclusively in the noncellulosomal fraction. When rArfA and rBgaA were incubated with β-1,4-xylanase A (XynA), a cellulosomal enzyme from
C. cellulovorans
, on plant cell wall polymers, the plant cell wall-degrading activity was synergistically increased compared with that observed with XynA alone. These results indicate that, to obtain effective plant cell wall degradation, there is synergy between noncellulosomal and cellulosomal subunits.
Transcription-Dependent Increase in Multiple Classes of Base Substitution Mutations in
Escherichia coli
Authors: Klapacz Joanna , Bhagwat Ashok S. 
Published: November 2002

ABSTRACT

We showed previously that transcription in
Escherichia coli
promotes C · G-to-T · A transitions due to increased deamination of cytosines to uracils in the nontranscribed but not the transcribed strand (A. Beletskii and A. S. Bhagwat, Proc. Natl. Acad. Sci. USA 93:13919-13924, 1996). To study mutations other than that of C to T, we developed a new genetic assay that selects only base substitution mutations and additionally excludes C · G to T · A transitions. This novel genetic reversion system is based on mutations in a termination codon and involves positive selection for resistance to bleomycin or kanamycin. Using this genetic system, we show here that transcription from a strong promoter increases the level of non-C-to-T as well as C-to-T mutations. We find that high-level transcription increases the level of non-C-to-T mutations in DNA repair-proficient cells in three different sequence contexts in two genes and that the rate of mutation is higher by a factor of 2 to 4 under these conditions. These increases are not caused by a growth advantage for the revertants and are restricted to genes that are induced for transcription. In particular, high levels of transcription do not create a general mutator phenotype in
E. coli
. Sequence analysis of the revertants revealed that the frequency of several different base substitutions increased upon transcription of the bleomycin resistance gene and that G · C-to-T · A transversions dominated the spectrum in cells transcribing the gene. These results suggest that high levels of transcription promote many different spontaneous base substitutions in
E. coli
.