bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intra‐ and intertumor heterogeneity in blood perfusion of human cervical cancer before treatment and after radiotherapy
Authors: Lyng Heidi , Vorren Ann O. , Sundfør Kolbein , Taksdal Ingeborg , Lien Hans H. , Kaalhus Olav , Rofstad Einar K. 
Published: November 2004

AbstractKnowledge of the intratumor heterogeneity in blood perfusion may lead to increased understanding of tumor response to treatment. In the present work, absolute perfusion values, in units of ml/g·min, were determined in 20 tumor subregions of patients with cervical cancer before treatment (n = 12) and after 2 weeks of radiotherapy (n = 8), by using a method based on contrast‐enhanced magnetic resonance imaging. The aims were to evaluate the intratumor heterogeneity in perfusion in relation to the intertumor heterogeneity and to search for changes in the heterogeneities during the early phase of therapy. The intra‐ and intertumor heterogeneity in perfusion were estimated from components of one‐way analyses of variance. The mean perfusion differed significantly among the patients before treatment, ranging from 0.044 to 0.12 ml/g·min. Large differences in perfusion were also observed within individual tumors. The heterogeneity was largest in the best perfused tumors, perfusion values ranging, e.g., from 0.055 to 0.29 ml/g·min were observed. The intratumor heterogeneity was similar to the intertumor heterogeneity. The mean perfusion generally increased or tended to increase during radiotherapy, ranging from 0.064 ml/g·min to 0.13 ml/g·min after 2 weeks of treatment. There was a tendency of increased intratumor heterogeneity in perfusion after therapy, consistent with the higher mean value; a difference in perfusion of more than a factor of 10 was seen within some tumors. These results suggest that cervix tumors contain a significant amount of poorly perfused subregions with high treatment resistance. Moreover, the perfusion and perfusion heterogeneity may increase during the early phase of radiotherapy and influence tumor response. © 2001 Wiley‐Liss, Inc.
Role of astrocytes in trimethyltin neurotoxicity
Authors: Gunasekar Palur G. , Mickova Vera , Kotyzova Dana , Li Li , Borowitz Joseph L. , Eybl Vladislav , Isom Gary E. 
Published: November 2004

AbstractAlthough the neurotoxicity of trimethyltin (TMT) is well known, mechanisms are still not clear. Glia have been proposed to mediate the toxic action of TMT on nerve cells. Accordingly, the effects of TMT were tested in primary neuronal cultures from rat cerebellum and compared to effects in astrocytes and mixed cultures. Neuronal damage observed following TMT exposure was less in the presence of astrocytes and astrocytes alone were resistant to TMT. Thus, astrocytes have a protective effect against TMT‐induced neurotoxicity. TMT caused an oxidative stress in granule cell cultures involving a variety of oxidative species ((O2)•−, H2O2, NO), but astrocytes were less sensitive to TMT‐induced oxidative species generation. Antioxidants, glutathione and 7‐nitroindazole attenuated neuronal cell death induced by TMT. It appears that oxidative stress mediates a large part of the destructive action of TMT in neuronal cultures. The presence of astrocytes appears to modulate TMT‐induced oxidative stress so that TMT causes only a small increase in lipid peroxidation in mouse brain after systemic administration. Thus, TMT induces a pronounced oxidative stress in cultured neurons, but when astrocytes are present, oxidative species play a lesser role in the neurotoxic action of TMT. © 2001 John Wiley & Sons, Inc. J Biochem Mol Toxicol 15:256–262, 2001
Sharp bounds for the number of 3‐independent partitions and the chromaticity of bipartite graphs
Authors: Dong F. M. , Koh K. M. , Teo K. L. , Little C. H. C. , Hendy M. D. 
Published: November 2004

AbstractGiven a graph G and an integer k ≥ 1, let α(G, k) denote the number of k‐independent partitions of G. Let 𝒦−s(p,q) (resp., 𝒦2−s(p,q)) denote the family of connected (resp., 2‐connected) graphs which are obtained from the complete bipartite graph Kp,q by deleting a set of s edges, where p ≥ q ≥ 2. This paper first gives a sharp upper bound for α(G,3), where G ∈ 𝒦 −s(p,q) and 0 ≤ s ≤ (p − 1)(q − 1) (resp., G ∈ 𝒦 2−s(p,q) and 0 ≤ s ≤ p + q − 4). These bounds are then used to show that if G ∈ 𝒦 −s(p,q) (resp., G ∈ 𝒦 2−s (p,q)), then the chromatic equivalence class of G is a subset of the union of the sets 𝒦−si(p+i,q−i) where max $\{-{s\over q-1},-{p-q\over 2}\}\!\le \,i \le{s\over p-1}$ and si = s − i(p−q+i) (resp., a subset of 𝒦2−s(p,q), where either 0 ≤ s ≤ q − 1, or s ≤ 2q − 3 and p ≥ q + 4). By applying these results, we show finally that any 2‐connected graph obtained from Kp,q by deleting a set of edges that forms a matching of size at most q − 1 or that induces a star is chromatically unique. © 2001 John Wiley & Sons, Inc. J Graph Theory 37: 48–77, 2001
On‐line preconcentration microliquid chromatography tandem mass spectrometric method for bradykinin analysis in plasma
Authors: Oosterkamp A. J. , Carrascal M. , Closa D. , Escolar G. , Gelpi E. , Abian J. 
Published: November 2004

AbstractThe practical limitations of miniaturized liquid chromatography (LC) methods for the analysis of endogenous peptides in plasma samples are studied. An automatic column switching method is used for on‐line micropreconcentration and microLC‐MS–MS (mass spectrometry) analysis of bradykinin and its metabolites in plasma. Both preconcentration (PC) and analytical columns were filled with C18 reversed phase due to the failure of anion exchange precolumns to retain bradykinins. The detection limit for bradykinin in water was 10 pmol/L (2 fmols on column) and a good linearity was found in the range 5–2000 fmols. In plasma, detection limit was 50 pmol/L (25 μL injected) with a linear response in the 100–2000 pmol/L range. Important rules for stable work were: (1) Cleaning the PC column after every run with pure acetonitrile (ACN) to eliminate organic matrix components; (2) to trap the more apolar organic matrix components on the analytical column to prevent their elution to the MS entrance; and (3) to set the electrospray needle to an off‐axis position to prevent accumulation of contaminants in the MS entrance. By using this setup, other procedures to reduce the organic load to the MS entrance such as the heart‐cutting of the peaks eluting from the LC column were not required. © 2001 John Wiley & Sons, Inc. J Micro Sep 13: 265–274, 2001
A novel extraction method for the higher order components of channel current in a GaAs MESFET
Authors: Kim Youngsik , Yi Jaehyok , Yang Youngoo , Kim Bumman 
Published: November 2004

AbstractA novel extractionion method has been proposed for direct extract of the higher order Taylor coefficients of the channel current Ids (Vgs, Vds) in a GaAs MESFET. Low‐frequency (45 and 70 MHz) two‐tone signals are employed to measure the harmonic component, and the load impedance was properly designed to find the cross terms. A Volterra series analysis is used for the formulation of Taylor series coefficients of the nonlinear channel current. This proposed parameter extraction procedure is simple and straightforward. The extracted current model is utilized successfully for intermodulation analysis. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 114–117, 2001.
Gain‐clamped erbium‐doped fiber amplifier using a single fiber Bragg grating
Authors: Subramaniam T. , Mahdi M. A. , Poopalan P. , Harun S. W. , Ahmad H. 
Published: November 2004

AbstractA new design of an all‐optical gain‐clamped erbium‐doped fiber amplifier is demonstrated. The amplifier is based on the conventional ring cavity, where the gain is clamped at 21.84 dB via optical feedback using a single fiber Bragg grating for an input signal power as high as −8 dBm. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 290–293, 2001.
Dual‐surface combined‐field integral equation for three‐dimensional scattering
Authors: Prakash V. V. S. , Mittra Raj 
Published: November 2004

AbstractIn this paper, a dual‐surface combined‐field integral equation (DS–CFIE) formulation is presented for computing electromagnetic scattering from perfectly conducting arbitrary three‐dimensional (3‐D) bodies. The formulation has the advantage that it does not suffer from the internal resonance problem associated with the closed cavity modes. Convergence is typically obtained in a few iterations, and the formulation is relatively insensitive to the location of the virtual surface. Numerical results are presented for the case of plane‐wave scattering from a conducting sphere and a cube to validate the present approach. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 293–296, 2001.
Time‐domain study of lossy nonuniform multiconductor transmission lines with complex nonlinear loads
Authors: Kabbaj Hassane , Zimmermann Jacques 
Published: November 2004

AbstractThis paper deals with a computational approach based upon the centered‐points finite‐difference time‐domain (FDTD) technique for evaluating voltages and currents along lossy nonuniform multiconductor transmission lines terminated with arbitrary loads. We emphasize the case of complex nonlinear loads, such as a metal semiconductor field‐effect transistor (MESFET). We illustrate and validate the FDTD technique with time‐domain reflectometer (TDR) experiments. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 296–301, 2001.
Furniture effects on the wideband indoor radio channel at microwave frequencies
Authors: Cuiñas Iñigo , Sánchez Manuel García 
Published: November 2004

AbstractTypically, ray‐tracing indoor simulators take into account the structural elements of the environment, but not other objects, such as furniture. Radio‐channel characteristics in empty and furnished environments have been measured along linear paths by using a wideband swept‐technique‐based sounder in a band around 5.8 GHz. Wideband parameters, such as delay spread and coherence bandwidth, exhibit important variations when the room is furnished as opposed to the situation when it is empty. Such effects are important, so radio network designers should modify their predictions to guarantee that the performance of wideband digital communication systems will be correct. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 336–340, 2001.
A compact bandpass filter using dielectric resonators for cellular portable telephones
Authors: Chen Yao‐Chung , Huang Cheng‐Lian 
Published: November 2004

AbstractThe microwave dielectric properties of a Ba(2−x)Sm(4+2x/3)Ti9O26 system (BST) (0.0≤x≤0.3) and the design procedures for a microwave coaxial dielectric bandpass filter are investigated in this work. Dielectric coaxial resonators with excellent dielectric properties of εr=75–80, a Q×f value=11,000, and great temperature stability at the resonant frequency (τf=∼0 ppm/°C) were used. Microwave bandpass filters for mobile communication systems were constructed by using such λ/4 coaxial resonators. Both air‐gap coupling and direct coupling methods were applied as the coupling instruments in the transformation of electromagnetic energy. The comb‐line theory was used to adjust the response of filters. The resonant frequency of each resonator, the coupling coefficients between adjacent resonators, and the external quality factor were adjusted to achieve the target specifications. The measured responses were in excellent agreement with the expected results. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 359–362, 2001.
Design of electromagnetic crystal filters for rectangular waveguides
Authors: Mendioroz Luis , Gonzalo Ramon , del Rio Carlos 
Published: November 2004

AbstractIn this paper, a new implementation of rectangular waveguide filters using dielectric periodic structures called electromagnetic crystals is presented. By tuning its forbidden band with the desired rejection band of the rectangular waveguide, the filtering behavior is obtained. The dependence of the filter features as a function of the periodic structure characteristics is shown. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 81–84, 2001.
p62&sol;p56 are cortical granule proteins that contribute to formation of the cortical granule envelope and play a role in mammalian preimplantation development
Authors: Hoodbhoy Tanya , Dandekar P. , Calarco P. , Talbot P. 
Published: November 2004

AbstractThe purpose of this study was to identify specific cortical granule protein&lpar;s&rpar; that form the cortical granule envelope and examine their role&lpar;s&rpar; in fertilization and preimplantation development. The polyclonal antibody A&hyphen;BL2 was used to show that the cortical granules of mice, rats, hamsters, cows, and pigs contain a pair of proteins designated p62&sol;p56. These proteins are released from hamster cortical granules at fertilization and contribute to formation of the cortical granule envelope, an extracellular matrix present in the perivitelline space of fertilized mammalian oocytes. P62&sol;p56 were present in the cortical granule envelope throughout preimplantation development and were found in blastomere cortices of 4&hyphen;cell to blastocyst stage embryos. Hamster oocytes fertilized in vivo in the presence of A&hyphen;BL2 were all monospermic, suggesting that p62&sol;p56 do not function in blocking polyspermy. Likewise treatment of morula to blastocyst stage hamster embryos with A&hyphen;BL2 had no effect on the implantation of blastocysts. However, cleavage divisions were inhibited in vivo in a dose&hyphen;dependent manner when fertilized oocytes or 2&hyphen;cell embryos were treated with A&hyphen;BL2. Inhibition of cell division was more pronounced in 2&hyphen;cell embryos than in fertilized oocytes. This study identifies p62&sol;p56 as cortical granule proteins that contribute to the formation of the cortical granule envelope and further supports the idea that after their release at fertilization, p62&sol;p56 function in regulating preimplantation development at the level of oocyte and blastomere cleavage. Mol. Reprod. Dev. 59:78&ndash;89, 2001. &copy; 2001 Wiley&hyphen;Liss, Inc.
Intramolecular basis set superposition errors
Authors: Senent M. L. , Wilson S. 
Published: November 2004

AbstractThe effects of intramolecular basis set superposition errors are less well documented than the corresponding intermolecular effects. The intramolecular basis set superposition errors are examined, using the approach of Jensen, for several basis sets developed by Pople and his co‐workers, which are widely used in studies of larger molecules. Prototype calculations are reported for the ground state of the water molecule using both the matrix Hartree–Fock method and the many‐body perturbation expansion for the correlation energy taken through second order. A similar investigation is carried out for some of the correlation consistent basis sets published by Dunning and his collaborators. Specifically, the following aspects are investigated: (i) the magnitude of the intramolecular basis set superposition error, (ii) the nonadditivity of intramolecular counterpoise corrections when applied in a pairwise fashion, and (iii) the use of multiple “ghost” centers. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 82: 282–292, 2001
Differentiation of α‐COOH from β‐COOH in aspartic acids by N‐phosphorylation
Authors: Chen Zhong‐Zhou , Tan Bo , Li Yan‐Mei , Zhao Yu‐Fen 
Published: November 2004

AbstractThe biomimic reactions of N‐phosphoryl amino acids, which involved intramolecular penta‐coordinate phosphoric‐carboxylic mixed anhydrides, are very important in the study of many biochemical processes. The reactivity difference between the α‐COOH group and β‐COOH in phosphoryl amino acids was studied by experiments and theoretical calculations. It was found that the α‐COOH group, and not β‐COOH, was involved in the ester exchange on phosphorus in experiment. From MNDO calculations, the energy of the penta‐coordinate phosphoric intermediate containing five‐member ring from α‐COOH was 35 kJ/mol lower than that of the six‐member one from β‐COOH. This result was in agreement with that predicted by HF/6‐31G** and B3LYP/6‐31G** calculations. Theoretical three‐dimensional potential energy surface for the intermediates predicted that the transition states 4 and 5 involving α‐COOH or β‐COOH group had energy barriers of ΔE=175.8 kJ⋅mol−1 and 210.4 kJ⋅mol−1, respectively. So the α‐COOH could be differentiated from β‐COOH intramolecularly in aspartic acids by N‐phosphorylation. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 41–51, 2001
Near ab initio quality molecular electrostatic potential maps using hybridization displacement charges at PM3 level and effects of geometrical changes in amino groups
Authors: Singh A. K. , Kushwaha P. S. , Mishra P. C. 
Published: November 2004

AbstractCharge distributions, dipole moments, and molecular electrostatic potentials (MEP) around several molecules consisting of carbon, nitrogen, oxygen, fluorine, sulfur, and chlorine atoms were studied using the PM3 semiempirical method and the results compared with those obtained using ab initio calculations at the RHF/6‐31G** level. Thus it is shown that relative MEP values near different atoms can be obtained using hybridization displacement charges (HDC) obtained by employing PM3 density matrices that usually agree quite satisfactorily with the ab initio ones. Further, positions of ab initio MEP minima are correctly located and the corresponding relative MEP values usually correctly predicted using the PM3(HDC) charges distributed continuously in three dimensions according to the forms of squares of valence s atomic orbitals. The necessary parameters for HDC calculations using the PM3 method were optimized. It is shown how within the frameworks of both PM3 and AM1 methods the π electrons or lone pairs associated with amino group nitrogen atoms and ring atoms can be satisfactorily treated in different situations. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 82: 299–312, 2001
Mnemonic symbols in commutator perturbation method
Authors: Matamala Adelio R. 
Published: November 2004

AbstractIn the present article special mnemonic symbols are defined to facilitate the calculation of the commutator perturbation method (CPM) series. CPM is a Lie‐algebraic version of the perturbation theory. The connection between CPM and the well‐known Rayleigh–Schrödinger perturbation theory (RSPT) is obtained by using a particular realization of these mnemonic symbols in terms of the spectral resolution of the model Hamiltonian (discrete states). © 2001 John Wiley & Sons, Inc. Int J Quant Chem 82: 263–268, 2001
Asymptotic distribution for the cost of linear probing hashing
Authors: Janson Svante 
Published: November 2004

AbstractWe study moments and asymptotic distributions of the construction cost, measured as the total displacement, for hash tables using linear probing. Four different methods are employed for different ranges of the parameters; together they yield a complete description. This extends earlier results by Flajolet, Poblete and Viola [On the analysis of linear probing hashing, Algorithmica 22 (1998), 490–515]. The average cost of unsuccessful searches is considered too. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 19: 438–471, 2001
An investigation of facilitator‐assisted and CONOPS‐based requirements elicitation methods using a 2 × 2 factorial experimental design
Authors: Gambhir S. Gulu 
Published: November 2004

AbstractSystem developments are frequently unsuccessful as measured in performance, cost, and schedule dimensions. Previous research has traced many development problems to poor system requirements. A method called Facilitator‐Assisted Requirements Elicitation (FARE), which employs a technical facilitator for discussion of requirements based on a Concept of Operations (CONOPS) Matrix, is developed and tested. A 2 × 2 factorial design was used to examine the effects of two independent variables on the FARE method: (1) facilitator presence or absence and (2) CONOPS Matrix or free‐form development. Twenty‐four subjects were randomly divided into four groups. Each group was given the task of developing a set of requirements and recording both a priority and rationale for the inclusion of each requirement. The three dependent variables are Communications, measured by responses to a post‐experiment survey; Requirements Scope, measured by subjective evaluation of requirements sets by an independent panel; and Requirements Quality, also measured by the independent panel. Results indicate a significant improvement in Communications when a facilitator was present. Requirements Scope showed a significant improvement when either a facilitator or the CONOPS Matrix was used, but was degraded when both elicitation techniques were used in combination. A significant improvement in Requirements Quality was observed when the groups were facilitated versus when they were not facilitated. Overall, both the presence of the facilitator and the use of the CONOPS Matrix showed benefits. Degradation in Requirements Scope, observed when both techniques were used in combination, is believed to be the result of the time constraints imposed on the subjects. The results of the experimentation support the use of FARE as an effective approach for capturing requirements early in the development lifecycle, thereby avoiding costly requirements changes. © 2001 John Wiley & Sons, Inc. Syst Eng 4: 272–286, 2001
Self and nonself recognition of chiral catalysts: The origin of nonlinear effects in the amino‐alcohol catalyzed asymmetric addition of diorganozincs to aldehydes
Authors: Noyori Ryoji , Suga Seiji , Oka Hiromasa , Kitamura Masato 
Published: November 2004

AbstractAsymmetric addition of dialkylzincs to aldehydes in the presence of (2S)‐3‐exo‐(dimethylamino)isoborneol [(S)‐DAIB] exhibits various nonclassical phenomena. The enantiomeric excess (ee) of the alkylation product, obtained with partially resolved DAIB, is much higher than that of the chiral amino alcohol, while the rate decreases considerably as the ee of DAIB is lowered. The asymmetric amplification effects reflect the relative turnover numbers of two enantiomorphic catalytic cycles, where an essential feature is the reversible homochiral and heterochiral dimerization of the coexisting enantiomeric DAIB‐based Zn catalysts. The interplay between the thermodynamics of the monomer/dimer equilibration and the kinetics of alkylation reaction strongly affect the overall profile of asymmetric catalysis. The self and nonself recognition of the chiral Zn catalysts is a general phenomenon when (S)‐DAIB is mixed with its enantiomer, diastereomer, or even an achiral β‐amino alcohol. The degree of nonlinearity is highly affected not only by the structures and purity of catalysts but also by various reaction parameters. The salient features have been clarified on the basis of molecular weight measurements, NMR and X‐ray crystallographic studies of organozinc complexes, and kinetic experiments, as well as computer‐aided quantitative analysis. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:85–100, 2001
Thailand: Opportunities and risks in a fast‐changing business environment
Authors: Wedel Paul F. , Rondinelli Dennis A. 
Published: November 2004

AbstractThailand's business environment is changing dramatically in the wake of the worst financial crisis and
economic recession in the country's recent history. Some of these changes may be ephemeral, and Thailand
will return to old business practices once the crisis eases, but many of the economic and political reforms now
being implemented can make trade and investment in Thailand easier, more transparent, and less affected by
corruption. Some of the reforms will not deliver the expected results. Others may increase uncertainty that will
be counterproductive in the short run. But some of the constitutional changes—the restructuring of family
controlled conglomerates, better regulation of the financial sector, demands for stronger corporate governance,
and new incentives for private investment—can have profound impacts on the country's business climate
and the way American companies do business in Thailand. © 2001 John Wiley & Sons, Inc.