bluuebunny/crossref_metadata_2025_split huggingface dataset:
The mechanism and modes of inhibition of arginine kinase from the cockroach (Periplaneta americana)
Authors: Brown Ashli E. , Grossman Steven H. 
Published: November 2004

AbstractThe kinetic mechanism and evaluation of several potential inhibitors of purified arginine kinase from the cockroach (Periplanta americana) were investigated. This monomeric phosphagen kinase is important in maintaining ATP levels during the rapid energy demands of muscle required for contraction and motility. Analysis reveals the following dissociation constants (mM) for the binary complex: E·Arg˜P → E + Arg˜P, K = 1.0; E·Arg → E + Arg, K = 0.45; E·MgATP → E + MgATP, K = 0.17; E·MgADP → E + MgADP, K = 0.12; and the ternary complex: Arg˜P·E·MgADP → E·MgADP + Arg˜P, K = 0.94; Arg·E·MgATP → E·MgATP + Arg, K = 0.49; MgATP·Enz·Arg → E·Arg +MgATP, K = 0.14; MgADP·E·Arg˜P → E·Arg˜P + MgADP, K = 0.09. For a particular substrate, the ratio of the dissociation constants for the binary to ternary complex is close to one, indicating little, if any, cooperativity in substrate binding for the rapid equilibrium, random addition mechanism. The time course of the arginine kinase reaction exhibits a pronounced curvature, which, as described for enzyme from other sources, is attributed to formation of an inhibitory catalytic dead‐end complex, MgADP·E·Arg. The curvature is accentuated by the addition of monovalent anions, including borate, thiocyanate, and, most notably, nitrite and nitrate. This effect is attributed to stabilization of the dead‐end complex through formation of a transition state analog. However, the substantial decrease in initial velocity (92%) caused by nitrate is due to an additional inhibitory effect, further characterized as non‐competitive inhibition (Ki = 8.0 mM) with the substrate L‐arginine. On the other hand, borate inhibition of the initial velocity is only 30% with significant subsequent curvature, suggesting that this anion functions as an inhibitor mainly by formation of a transition state analog. However, some component of the borate inhibition appears to be mediated by an apparent partial competitive inhibition with L‐arginine. D‐arginine is not a substrate for arginine kinase from the cockroach, but is an effective competitive inhibitor with a Ki = 0.31 mM. L‐Canavanine is a weak substrate for arginine kinase (Km = 6.7 mM) with a Vmax for the pure enzyme that is approximately one‐third that of L‐arginine. However, initial velocity experiments of substrate mixtures suggest that competition between L‐canavanine and L‐arginine may not be a simple summation effect and may involve a structural modification. Sensitivity of arginine kinase activity to D‐arginine as well as nitrate and borate anions, coupled with the fact that L‐arginine is an essential amino acid for the cockroach, suggest that arginine kinase could be a useful chemotherapeutic target for the control of cockroach proliferation. Arch. Insect Biochem. Physiol. 57:166–177, 2004. © 2004 Wiley‐Liss, Inc.
Conveying taxonomy context for topic‐focused Web search
Authors: Pahlevi Said Mirza , Kitagawa Hiroyuki 
Published: November 2004

AbstractIntroducing context to a user query is effective to improve the search effectiveness. In this article we propose a method employing the taxonomy‐based search services such as Web directories to facilitate searches in any Web search interfaces that support Boolean queries. The proposed method enables one to convey current search context on taxonomy of a taxonomy‐based search service to the searches conducted with the Web search interfaces. The basic idea is to learn the search context in the form of a Boolean condition that is commonly accepted by many Web search interfaces, and to use the condition to modify the user query before forwarding it to the Web search interfaces. To guarantee that the modified query can always be processed by the Web search interfaces and to make the method adaptive to different user requirements on search result effectiveness, we have developed new fast classification learning algorithms.
Price discovery in the Texas cash cattle market
Authors: Bessler David A. , Davis Ernest E. 
Published: November 2004

AbstractTime series methods and directed acyclic graphs are used to uncover the centre of price discovery in 10 weight/gender classes of feeder and fed cattle from cash markets in Texas, U.S.A. Heavy feeder heifers, animals sitting on a margin of feeding for meat or breeding for new stocks, are weakly exogenous in an error correction representation of these prices. Further, contemporaneous price innovations from this class of animals cause price innovations in feeder steers and lighter weight feeder heifers. Innovation accounting shows the prominent role that heavy heifers play in cattle price discovery. Copyright © 2004 John Wiley & Sons, Ltd.
Crown‐Tetrathiafulvalenes Attached to a Pyrrole or an EDOT Unit: Synthesis, Electropolymerization and Recognition Properties
Authors: Trippé Gaëlle , Le Derf Franck , Lyskawa Joël , Mazari Miloud , Roncali Jean , Gorgues Alain , Levillain Eric , Sallé Marc 
Published: November 2004

AbstractA crown‐tetrathiafulvalene electroactive receptor has been covalently linked to electropolymerizable pyrrole or 3,4‐ethylenedioxythiophene monomers. The synthetic route to the monofonctionalized tetrathiafulvalene (TTF) ligand has been optimized. Two derivatives of pyrrole (N‐ and 3‐substituted) were synthesized. The various substituted monomers have been electropolymerized to produce polypyrrole (PP) and poly(ethylenedioxothiophene) (PEDOT) films bearing the electroactive TTF moiety. The electroactivity of the polymer films is efficiently controlled by the well‐defined two‐step redox behavior of the TTF unit. In the case of PEDOT, an alternative post‐polymerization derivatization strategy has been used, involving the grafting of the crown‐TTF ligand on the previously grown PEDOT backbone. Though chemical derivatization is realized under heterogeneous conditions, in the bulk of the film, this strategy proved to be particularly efficient. These electrodes constitute the first examples of conducting polymer‐based modified electrodes incorporating a TTF electrochemical probe, able to interact with a guest ion, such as Ba2+. The cation recognition properties of these various electrodes have been analyzed by cyclic voltammetry and their electroactivity in water as well as their regeneration capability have been investigated.
Electronic Structure and Chain‐Length Effects in Diplatinum Polyynediyl Complexes trans,trans‐[(X)(R3P)2Pt(CC)nPt(PR3)2(X)]: A Computational Investigation
Authors: Zhuravlev Fedor , Gladysz John A. 
Published: November 2004

AbstractStructure and bonding in the title complexes are studied using model compounds trans,trans‐[(C6H5)(H3P)2Pt(CC)nPt(PH3)2(C6H5)] (PtCxPt; x=2n=4–26) at the B3LYP/LACVP* level of density functional theory. Conformations in which the platinum square planes are parallel are very slightly more stable than those in which they are perpendicular (ΔE=0.12 kcal mol−1 for PtC8Pt). As the carbon‐chain length increases, progressively longer CC triple bonds and shorter CC single bonds are found. Whereas the triple bonds in HCxH become longer (and the single bonds shorter) as the interior of the chain is approached, the PtCC triple bonds in PtCxPt are longer than the neighboring triple bond. Also, the PtC bonds are shorter at longer chain lengths, but not the HC bonds. Accordingly, natural bond orbital charge distributions show that the platinum atoms become more positively charged, and the carbon chain more negatively charged, as the chain is lengthened. Furthermore, the negative charge is localized at the two terminal CC atoms, elongating this triple bond. Charge decomposition analyses show no significant d–π* backbonding. The HOMOs of PtCxPt can be viewed as antibonding combinations of the highest occupied π orbital of the sp‐carbon chain and filled in‐plane platinum d orbitals. The platinum character is roughly proportional to the Pt/Cx/Pt composition (e.g., x=4, 31 %; x=20, 6 %). The HOMO and LUMO energies monotonically decrease with chain length, the latter somewhat more rapidly so that the HOMO–LUMO gap also decreases. In contrast, the HOMO energies of HCxH increase with chain length; the origin of this dichotomy is analyzed. The electronic spectra of PtC4Pt to PtC10Pt are simulated. These consist of two π–π* bands that redshift with increasing chain length and are closely paralleled by real systems. A finite HOMO–LUMO gap is predicted for PtC∞Pt. The structures of PtCxPt are not strictly linear (average bond angles 179.7°–178.8°), and the carbon chains give low‐frequency fundamental vibrations (x=4, 146 cm−1; x=26, 4 cm−1). When the bond angles in PtC12Pt are constrained to 174° in a bow conformation, similar to a crystal structure, the energy increase is only 2 kcal mol−1. The above conclusions should extrapolate to (CC)n systems with other metal endgroups.
The prognostic significance of bone marrow levels of neurofibromatosis‐1 protein and ras oncogene mutations in patients with acute myeloid leukemia and myelodysplastic syndrome
Authors: Lu Di , Nounou Randa , Beran Miloslav , Estey Elihu , Manshouri Taghi , Kantarjian Hagop , Keating Michael J. , Albitar Maher 
Published: November 2004

AbstractBACKGROUNDIt has been reported that point mutations of the ras gene occur frequently in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). However, the prognostic significance of ras gene mutations in patients with these disorders has been a controversial issue. Although abnormalities in the neurofibromatosis 1 (NF1) gene, which is a gene involved in the ras pathway, have been observed frequently in patients with juvenile chronic myelogenous leukemia, the role of these abnormalities in adult patients with AML or MDS is not clear.METHODSIn this study, bone marrow specimens that were obtained from previously untreated patients with AML and MDS were examined for ras mutations, and the levels of NF1 protein expression were measured.RESULTSRas point mutations were detected in 16 of 83 patients with AML (19%) and in 21 of 90 patients with MDS (23%). Fourteen of 28 patients with chronic myelomonocytic leukemia (50%) had ras gene mutations. Decreased bone marrow levels of NF1 protein (< 70% of the median level detected in control bone marrow specimens) were observed in 20 of 66 patients with AML (30.3%) and in 8 of 29 patients with MDS (27.6%); none of the patients with ras gene mutations had decreased bone marrow levels of NF1 protein. The presence of a mutant ras gene was associated with a shorter complete remission duration (CRD) in patients with MDS (P = 0.05) but had no effect on survival in patients with AML or MDS. Patients with AML who had decreased NF1 protein levels had a slightly longer CRD compared with patients who had normal NF1 levels (P = 0.07). However, the NF1 level had no significant impact on survival among patients with AML or MDS. When patients with low NF1 levels were grouped with patients who had ras mutations, the patients who had AML had a significantly longer CRD compared with the patients who had MDS (P = 0.02).CONCLUSIONSThe current results suggest that a reduction in NF1 protein expression and the presence of ras point mutations may complement each other and that they both play a complex role in the biology of AML and MDS. Cancer 2003;97:441–9. © 2003 American Cancer Society.DOI 10.1002/cncr.11036
Agenesis and microdontia of permanent teeth as late adverse effects after stem cell transplantation in young children
Authors: Hölttä Päivi , Alaluusua Satu , Saarinen‐Pihkala Ulla M. , Peltola Jaakko , Hovi Liisa 
Published: November 2004

AbstractBACKGROUNDThe objective of the current study was to examine the occurrence of tooth agenesis and microdontia in pediatric stem cell transplantation (SCT) recipients.METHODSThe impact of total body irradiation (TBI) and age at SCT on agenesis and microdontia of permanent teeth was examined in 55 patients from panoramic radiographs. Assessment A1 (for tooth agenesis and microdontia) excluded the third molars, and assessment A2 (for tooth agenesis) included the third molars. Patients were grouped according to TBI status (the TBI group vs. the non‐TBI group) and age at SCT (patients age ≤ 3.0 years [Group Y], patients ages 3.1–5.0 years [Group M], and patients age ≥ 5.1 years [Group O]).RESULTSFrom 1 to 12 teeth were missing in 77%, 40%, and 0% of patients (assessment A1) in Groups Y, M, and O, respectively (Group Y vs. Group M, P = 0.055; Group Y vs. Group O, P < 0.001; and Group M vs. Group O, P = 0.002), increasing to 83%, 78%, and 43%, respectively, when the third molars were included (assessment A2; P values were not significant). Correspondingly, 75%, 60%, and 13%, respectively, of patients had 1–12 microdontic teeth (assessment A1: Group Y vs. Group M, P = 0.306; Group Y vs. Group O, P < 0.001; and Group M vs. Group O, P = 0.003). Recipient age at the time of SCT was found to have a negative correlation with the number of missing teeth (P = 0.001) and microdontic teeth (P = 0.005). TBI appeared to have little effect on the prevalence of tooth agenesis (assessment A1: TBI group, 32%; non‐TBI group, 29%; assessment A2: TBI group, 72%; non‐TBI group, 46%; P values were not significant) or on the prevalence of microdontia (assessment A1: TBI, 41%; non‐TBI, 50%; P value was not significant). A tendency toward an increased number of affected teeth was noticed in the group of patients who received TBI.CONCLUSIONSDepending on their age at SCT, 50–100% of pediatric SCT recipients will later present with agenesis and/or microdontia of permanent teeth that may jeopardize occlusal development. Young age (≤ 5.0 years) at SCT was found to be a stronger risk factor than TBI, although TBI caused additive impairment. Cancer, 2005. © 2004 American Cancer Society.
All‐optical analog‐to‐digital conversion based on fiber nonlinearity
Authors: Oda Sho‐ichiro , Mao Xuelong , Maruta Akihiro , Kitayama Ken‐ichi 
Published: November 2004

AbstractRecently, research on optical analog‐to‐digital (A‐D) conversion not restricted by the operating speed of electronic devices has been carried out extensively. However, the operation in the optical domain is limited up to sampling. Operations subsequent to quantization are carried out by using electronic devices. The authors proposed a method to realize both sampling and quantization in the A‐D conversion simultaneously in the optical domain. In this method, four‐wave mixing in the fiber is used for optical sampling and the soliton effects in a fiber are used for optical quantization. In this paper, the principle of the proposed method is described first. Numerical simulation demonstrates its effectiveness. Further, a proof‐of‐concept experiment is carried out, confirming its realizability. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(3): 53–62, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20149
V‐shaped diversity antenna for microcell station
Authors: Komai Tomohiro , Hori Toshikazu , Cho Keizo , Yamamoto Heiichi , Okada Minoru 
Published: November 2004

AbstractIn microcell systems such as PHS in which the antenna height is low and the cell radius is small, many antennas are installed on the street so that they are easily seen. Hence, the antenna shapes must be adapted to the aesthetics of urban areas. Also, the handsets are often used indoors, so that the radio waves reach the antenna after several reflections by buildings, and many cross polarization components are present. As an optimum diversity antenna taking account of such propagation characteristics, a bar‐shaped diversity antenna of V shape is proposed. In this paper, based on an analysis of the antenna radiation characteristics by the method of moments and simulation of the diversity effect, a configuration of a V‐shaped diversity antenna suitable for microcell systems is demonstrated. The antenna gain is improved in the direction of antenna inclination. Since many cross polarization components are contained in urban propagation, the diversity effect considering this situation is clarified. It is found that the diversity gain exceeds that for the conventional collinear antenna and that an improvement of more than 3 dB can be attained with a diversity reception level of 1%. Hence, the characteristics are found to be suitable for street microcell configurations. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(3): 11–20, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20179
Elimination of interference due to IQ imbalance for OFCDM direct conversion receiver
Authors: Yuba Tadaaki , Sanada Yukitoshi 
Published: November 2004

AbstractRecently, with a view to reducing the size and power consumption of wireless receivers, research on direct conversion schemes has been carried out extensively. One of the problems in the direct conversion receiver is IQ imbalance. In the direct conversion receiver, a π/2 phase shifter for RF is required. However, it is difficult to operate a phase shifter with an accurate phase shift value over a broad bandwidth. As a result, the IQ balance of the demodulated signals varies. In the case of OFCDM signals, this IQ imbalance affects the demodulated signals as intercarrier interference (ICI). In the present paper, correction of the IQ imbalance by signal processing is considered for reduction of the effect. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(3): 1–10, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20182
Absence of genotoxicity of a phytotherapeutic extract from Stryphnodendron adstringens (Mart.) Coville in somatic and germ cells of Drosophila melanogaster
Authors: de Sousa Neila Coelho , de Carvalho Salvador , Spanó Mário Antônio , Graf Ulrich 
Published: November 2004

AbstractStryphnodendron adstringens (Mart.) Coville, a medicinal plant that grows in the “cerrados” (a savanna ecosystem) of Brazil, popularly known as “Barbatimão,” is an important source of tannins (polyphenols). In Brazil, it is used in industry (mainly as vegetable tanning) and also in traditional medicine for the treatment of various diseases. In the present study, a phytotherapeutic extract from S. adstringens stem bark was evaluated for mutagenic and recombinagenic effects using the wing spot test of Drosophila melanogaster (somatic mutation and recombination test, SMART), and for chromosome damage in germ cells using the Drosophila sex‐chromosome loss test (ring‐X loss). For SMART, the standard as well as the high bioactivation fly crosses were used; the latter cross is characterized by a high sensitivity to promutagens and procarcinogens. Third‐instar larvae from these two crosses were treated for 48 hr with different concentrations (66%, 75%, and 100%) of the phytotherapeutic extract. The wings of the emerging adults were analyzed for the occurrence of different types of mutant spots. No statistically significant differences in spot frequencies between controls and treated series were observed. For the ring‐X loss test, adult males were fed with the same concentrations of the extract as in the wing spot test. No statistically significant increases in ring‐X losses were observed. The results of our experiments suggest that the phytotherapeutic extract from S. adstringens stem bark is not genotoxic in somatic and germ cells of D. melanogaster. Environ. Mol. Mutagen. 41:293–299, 2003. © 2003 Wiley‐Liss, Inc.
Loss of heterozygosity analysis of mouse pulmonary adenomas induced by coal tar
Authors: Benavides Fernando , Conti Claudio J. , LaCava Margaret , Flores Mónica , Glasscock Edward , Sternik Gabriel , Gimenez‐Conti Irma B. , Johnston Dennis A. , Dunsford Harold A. , Goldstein Lawrence S. , Rodriguez Lewis V. 
Published: November 2004

AbstractManufactured gas plant (MGP) residues, commonly known as coal tars, were generated several decades ago as a byproduct of residential and industrial gas production from the distillation of coal. Previous short‐term exposure studies have shown MGP residues to be tumorigenic in mouse liver and lung. In order to gain further insight into carcinogenesis by complex mixtures of environmental chemicals containing known carcinogenic polycyclic aromatic hydrocarbons, we investigated mouse pulmonary tumors for loss of heterozygosity (LOH) as a result of multiple exposure to MGP residues. Twenty mouse lung adenomas produced in (C57BL/6 × C3H)F1 hybrid mice and manually microdissected were selected to examine genome‐wide allelic losses at 58 microsatellite loci. Regions of chromosomes 1, 4, 5, 8, and 11 were affected in 30–40% of tumors. The elevated rates of allelic imbalance in these chromosomes may indicate the location of unknown tumor suppressor genes significant to neoplastic transformation in mouse lung tissues. Laser capture microdissection‐based LOH analysis of pulmonary adenomas showed that contamination of nonneoplastic tissues was not masking the allelic losses in the manually microdissected tumor analysis. The low frequency of chromosome instability in these tumors, measured by means of inter‐simple sequence repeat PCR, suggests the presence of discrete regions of LOH instead of extensive structural rearrangements. Environ. Mol. Mutagen. 41:300–308, 2003. © 2003 Wiley‐Liss, Inc.
A recurrent duodenal gastrointestinal stromal tumor with a frameshift mutation resulting in a stop codon in KIT exon 13
Authors: Vu Hoang Anh , Xinh Phan Thi , Kikushima Makoto , Zhu Yi , Tokuhara Makoto , Tani Masayoshi , Shimizu Toshio , Saito Kiyoshi , Tokunaga Katsushi , Sato Yuko 
Published: November 2004

AbstractGastrointestinal stromal tumors (GISTs) are a specific and rare subset of human gastrointestinal tract tumors. Most GISTs show gain‐of‐function mutations of KIT, mainly in exon 11, that always maintain the reading frame. We report on data from a 43‐year‐old Japanese man with recurrent duodenal GIST and a frameshift mutation in KIT exon 13 together with an in‐frame deletion in KIT exon 11 detected by genomic DNA sequencing. Deletion of 48 base pairs of KIT exon 11, which preserved the reading frame, was identified in both primary and recurrent tumors, whereas deletion of one nucleotide of codon 642 of KIT exon 13, which changed the reading frame and induced a novel stop codon at amino acid 644, was found only in the recurrent tumor. The predicted protein resulting from the latter would lack part of the kinase domain. To the best of our knowledge, this is the first documentation of a GIST with a frameshift mutation of KIT. © 2004 Wiley‐Liss, Inc.