bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Binuclear Copper Complexes [(9S3)Cu(CN)Cu(9S3)]Xn (X=BF4, n=1; X=TCNQ, n=2) (9S3=1, 4, 7‐trithiacyclononane): Syntheses, Crystal Structures and Magnetic Properties
Authors: Naito T. , Nishibe K. , Inabe T. 
Published: December 2004

AbstractThe binuclear Cu complex salts of 1, 4, 7‐trithiacyclononane (9S3) with an inorganic anion (BF4)‐ and with an organic radical anion TCNQ‐ (7, 7′, 8, 8′‐tetracyanoquinodimethanide) were synthesized and their molecular and crystal structures were examined in connection with the magnetic properties. The new complex cation [Cu(9S3)CN(9S3)Cu]+ varies its charges and magnetic properties depending on the counter anions; [Cu(9S3)CN(9S3)Cu](BF4) (1) was obtained as diamagnetic colorless crystals, while [Cu(9S3)CN(9S3)Cu](TCNQ)2 (2) was obtained as dark blue crystals with antiferromagnetic properties. Complex 1 crystallized in the monoclinic space group C2/c with a = 26.863(2), b = 7.0878(5), c = 13.4864(8) Å, β = 116.318(2)°. Complex 2 crystallized in the triclinic space group P1¯ with a = 12.521(1), b = 20.2698(8), c = 8.0205(4) Å, α = 100.688(4), β = 93.846(5), γ = 94.953(4)°. Both complexes are comprised of cyano‐bridged two Cu(9S3) ions with tetrahedral coordination. The X‐ray structural study revealed that 1 has two crystallographically equivalent copper(I) atoms, while 2 has two crystallographically independent CuI/II sites. The two CuI/II sites could not be distinguished from the X‐ray structural study. For 2 the IR spectra show that both crystallographically independent TCNQ species were monoanions and are strongly dimerized due to π‐stacking, which well explains their diamagnetic contribution to the magnetic susceptibility and the highly insulating property of this salt. The temperature‐dependent magnetic susceptibility of 2 showed a deviation from the Curie‐Weiss behaviour around 60 K, which indicates a strong antiferromagnetic intermolecular interaction between the copper complexes and that such intermolecular interaction should partly occur via the TCNQ radical anion dimer.
Donorstabilisierte Galliumdihalogenide Ga2X4·2D (X = Cl, Br; D = Donormolekül): Ein experimenteller Beitrag zu den Variationsmöglichkeiten der Ga‐Ga‐Einfachbindung
Authors: Duan Taike , Schnöckel Hansgeorg 
Published: December 2004

AbstractBei der Disproportionierung metastabiler GaX‐Lösungen (X = Cl, Br) werden im Bereich der Oxidationsprodukte u.a. donorstabilisierte Galliumdihalogenide gebildet. Sie haben nach Röntgenstrukturanalysen eine dimere Form DX2Ga‐GaX2D (D = THF, NHEt2, NEt3, 4‐tButylpyridin oder Br‐), d.h. diese Verbindungen sind zu Ethan isoelektronisch, d.h. sie sind in einer schematischen Betrachtung als Vertreter kettenförmiger, alkanartiger Galliumsubhalogenide zu bezeichnen: Gan(X, D)2n+2. Die Ga‐Ga‐Bindungen dieser Halogenide sind kürzer als in Organometallverbindungen vom Typ R2Ga‐GaR2. Der Vergleich der Bindungsparameter, besonders der Ga‐Ga‐Bindungen in diesen Dihalogeniden, erlaubt Rückschlüsse auf den strukturellen Einfluss sowohl der Donormoleküle als auch der Halogenidliganden.
1‐Azonia‐2‐boratanaphthalenes
Authors: Paetzold Peter , Stanescu Claudia , Stubenrauch Jörg Rainer , Bienmüller Matthias , Englert Ulli 
Published: December 2004

AbstractThe 1‐azonia‐2‐boratanaphthalenes (NH)(BX)C8H6 can be synthesized from 2‐aminostyrene and the dihaloboranes XBHal2 (1‐4: X = Cl, Br, iPr, tBu). Further derivatives (NH)(BX)C8H6 are obtained from 1 by replacing Cl by alkoxy or alkyl groups [5‐8: X = OMe, OtBu, Me, (CH2)3NMe2]. The hydrolysis of 1 gives a mixture of the bis(azoniaboratanaphthyl) oxide [(NH)BC8H6]2O (9) and the hydroxy derivative (NH)[B(OH)]C8H6 (10). The diboryl oxide 9 crystallizes in the space group C2/c. The lithiation of 4 at the nitrogen atom gives [NLi(tmen)](BtBu)C8H6 (11), which upon reaction with the diborane(4) B2Cl2(NMe2)2 yields the 1, 2‐bis(azoniaboratanaphthyl)diborane B2[N(BtBu)C8H6]2(NMe2)2 (12). The 2‐chloro‐1‐methyl‐4‐phenyl derivative (NMe)(BCl)C8H5Ph (13) of the parent (NH)(BH)C8H6 can be synthesized from the aminoborane BCl2(NMePh) and phenylethyne. Substitution of Cl in 13 gives the derivatives (NMe)(BX)C8H5Ph [14‐20: X = N(SiMe3)2, Me, Et, iBu, tBu, CH2SiMe3, Ph] and the reaction of 13 with Li2O affords the bis(azoniaboratanaphthyl) oxide [(NMe)BC8H5Ph]2O (21). The reaction of 16 or 19 with [(MeCN)3Cr(CO)3] yields the complexes [{(NMe)(BX)C8H5Ph}Cr(CO)3] (22, 23: X = Et, CH2SiMe3), in which the chromium atom is hexahapto bound to the homoarene part of 16 or 19, respectively. The complex 23 crystallizes in the space group P21/c. Upon reaction of the phenols para‐C6H4R(OH) with the aryldichloroboranes ArBCl2 and subsequent condensation of the products with phenylethyne, the 1‐oxonia‐2‐boratanaphthalenes O(BAr)C8H4RPh with R in position 6 and Ph in position 4 are formed (24‐26: Ar = Ph, R = H, Me, OMe; 27‐29: Ar = C6F5, R = H, Me, OMe). The azoniaboratanaphthalenes 1‐23 were characterized by NMR methods.
Existiert eine Wurtzit‐Modifikation von Lithiumbromid? — Untersuchungen im System LiBr/LiI —
Authors: Fischer Dieter , Müller Adolf , Jansen Martin 
Published: December 2004

AbstractGasphasenabscheidungen inniger Gemenge von LiBr/LiI (Mischungsverhältnis: LiBr/LiI = 3:1, 2:1, 1:1, 1:2, 1:3, 1:4) sowie von reinem LiI bzw. LiBr auf einem Saphirsubstrat bei ‐196 °C in einer Hochvakuumkammer wurden röntgenographisch in Abhängigkeit der Temperatur untersucht. Unterhalb von 0 °C liegt LiI in der hexagonalen Wurtzit‐Modifikation (β‐LiI) mit a = 451.4(1) und c = 731.1(2) pm vor, die sich beim weiteren Erwärmen bis Raumtemperatur in die kubische Kochsalz‐Modifikation (α‐LiI, a = 602.57(3) pm) umwandelt. Aus den Koabscheidungen von LiBr/LiI entstehen feste Lösungen LiBr1‐xIx, die ebenfalls unterhalb von Raumtemperatur in einer Wurtzit‐Modifikation kristallisieren. Diese sind beständiger als β‐LiI und wandeln sich erst bei 80 °C endgültig in die kubischen Phasen um. Die Gitterkonstanten betragen für LiBr1‐xIx mit x ≈ 0.7 a = 445.48(7), c = 719.1(1) pm und für x ≈ 0.4 a = 431.50(5), c = 691.7(1) pm. Es liegt eine lückenlose Mischkristallreihe für die hexagonale Phase LiBr1‐xIx mit 0.25 ≤ x ≤ 0.8 vor. Beide kubische Phasen, α‐LiI und LiBr, bilden feste Lösungen, in denen bis zu etwa 10 % der jeweils anderen Verbindung gelöst sind. Für reines LiBr wurde im gesamten Temperaturbereich (‐196 °C bis 25 °C) ausschließlich die kubische Modifikation (a = 551.54(2) pm, 25 °C) beobachtet.
Synthesen und Kristallstrukturen der chalkogenidoverbrückten Nickelclusterverbindungen [Ni5Se4Cl2(PPhEt2)6], [Ni12Se12(PnPr3)6] und [Ni18S18(PiPr3)6]
Authors: Koenig Sven , Fenske Dieter 
Published: December 2004

AbstractDurch die Reaktion von silylierten Chalkogenverbindungen (R)ESiMe3 (R = SiMe3, Mes = C9H11; E = S, Se) mit [NiCl2(PPhEt2)2] und[NiCl2(PR3)2] (R = nPr, iPr) in THF können chalkogenidoverbrückte Nickelcluster dargestellt werden. In dieser Arbeit werden die Verbindungen [Ni5Se4Cl2(PPhEt2)6]·2THF (1), [Ni12Se12(PnPr3)6]·2THF (2) und [Ni18S18(PiPr3)6]·2THF (3) beschrieben, deren Strukturen mit Hilfe der Röntgenstrukturanalyse aufgeklärt werden konnten.
Cytosolic compartmentalization of hepatic alanine: Glyoxylate aminotransferase in patients with aberrant peroxisomal biogenesis and its effect on oxalate metabolism
Authors: Danpure C. J. , Fryer P. , Griffiths S. , Guttridge K. M. , Jennings P. R. , Allsop J. , Moser A. B. , Naidu S. , Moser H. W. , MacCollin M. , DeVivo D. C. 
Published: December 2004

SummaryTwo patients with atypical manifestations of aberrant peroxisomal biogenesis are described. Contrary to previous studies, which had shown that Zellweger syndrome patients usually have normal levels of urinary oxalate excretion, the patients in the present study had evidence of abnormal oxalate metabolism in the form of hyperoxaluria and, in one of the patients, calcium oxalate urolithiasis. Activity of the liver‐specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT), which is a major determinant of the level of endogenous oxalate synthesis in humans, was normal in one patient and markedly supranormal in the other. Using the technique of post‐embedding protein A‐colloidal gold immunoelectron microscopy, AGT was found to be mainly cytosolic in the livers of both patients, with significant amounts also localized in the nuclei. In a small minority of the hepatocytes of one patient, who was homozygous for the more common (major) AGT allele, large numbers of unidentified fibrillar arrays were found in the cytosol, which labelled heavily for immunoreactive AGT. The background cytosolic AGT labelling was markedly reduced in such cells when compared to the majority of cells that did not contain fibrils. In the other patient, who was heterozygous for the major and minor AGT alleles, there appeared to be low levels of mitochondrial AGT labelling. In the light of these data, the possible metabolic function of cytosolic AGT in the livers of panperoxisomal disease patients is discussed.
6‐Methyluracil excretion in 2‐methylacetoacetyl‐CoA thiolase deficiency and in two children with an unexplained recurrent ketoacidaemia
Authors: Cromby C. H. , Manning N. J. , Pollitt R. J. , Powell S. , Bennett M. J. 
Published: December 2004

Summary6‐Methyluracil (6MU) has been identified in urine collected during acute illness in two children with β‐ketothiolase deficiency (approximately 1 mmol/L) and in two children with recurrent infection‐related ketoacidaemia of unknown aetiology (levels of 6.3 and 7.1 mmol/mmol creatinine). Significant amounts of 6MU were not detected in children with fasting ketosis in whom a metabolic disorder was excluded (normal levels less than 25 µmol/mmol creatinine). We propose that the production of 6MU may be related to the accumulation of acetoacetyl‐CoA and thus be a marker for disorders where this occurs.
Mucopolysaccharidosis type II (Hunter syndrome): Characterization of the iduronate‐2‐sulphatase in MPS II skin fibroblasts
Authors: Petruschka L. , Zschiesche M. , Bielicki J. , Seidlitz G. , Machill G. , Hopwood J. J. , Herrmann F. H. 
Published: December 2004

SummaryIduronate‐2‐sulphatase was characterized kinetically in MPS II fibroblasts.
Holocene Alluvial Stratigraphy in the Upper Susquehanna River Basin, New York
Authors: Scully Richard W. , Arnold Richard W. 
Published: December 2004

AbstractTwo alluvial terraces and the present flood plain were studied at two locations along the Susquehanna and Unadilla Rivers in south-central New York state. They have formed since deglaciation and incision of the stream channels into the valley train deposits. The higher terrace has noncumulative soil profiles with well-developed color B horizons predominantly of silt loam and very fine sandy loam. The terrace is weathered to a degree similar to nearby glacial outwash terraces that have caps of similarly textured sediments. Incision that produced the terrace occurred before 9705 ± 130 yr B.P. The lower terrace is characterized by relatively thick, vertical-accretion deposits of silt loam that contain sequences of thin, buried A, color B, and C horizons. They were formed between about 3240 ± 110 (14C data of soil humin) and 235 ± 80 yr B.P. Deposits above the 235 ± 80 yr B.P. stratum are unweathered. The soil stratigraphy and 14C dates of soil humin from buried A horizons are surprisingly well correlated between sites. Most sediments of the present flood plain have been deposited since 1120 ± 80 yr B.P. Incipient A horizons and oxidation of inherited organic matter in the subsoil are the only evidence of pedogenesis in the flood-plain deposits that are older than 275 ± 80 yr B.P. The most recent flood-plain fill deposited since then is unaltered. These youngest sediments of the flood plain along with the youngest veneer of vertical-accretion deposits on the lowest terrace are associated with an increased rate of deposition largely attributable to clearing of the forests by settlers, beginning in the late 1700s. Comparison of the alluvial stratigraphy with the radiocarbon-dated pollen stratigraphy of southwestern New York (Miller 1973) reveals some apparent time correlations between alluvial events and vegetation changes. This gives reason to speculate that climatic change or forest catastrophes such as disease or drought are causes of some of the alluvial events.
Old Crow Tephra Found at the Palisades of the Yukon, Alaska
Authors: Begét James , Edwards Mary , Hopkins David , Keskinen Mary , Kukla George 
Published: December 2004

AbstractA 20-cm-thick volcanic ash layer at the Palisades along the Yukon River is geochemically correlated with the Old Crow tephra. A buried organic and wood-rich layer above the Old Crow tephra probably records the last interglaciation. The recognition of the Old Crow tephra provides the first chronologic information on the age of the thick sequence of Pleistocene sediments at the Palisades, an important ice-age mammal site in central Alaska and a key locality for the reconstruction of the history of the Yukon River and the last interglaciation in central Alaska.
Factors associated with inadequate prenatal care in Ecuadorian women
Authors: Paredes I. , Hidalgo L. , Chedraui P. , Palma J. , Eugenio J. 
Published: December 2004

AbstractBackgroundAlthough inadequate prenatal care has been associated with adverse perinatal outcomes, reports on the factors associated with poor prenatal care in developing Latin American countries are scarce.ObjectiveTo determine factors associated with inadequate prenatal care among women from low socioeconomic circumstances.MethodWomen delivered after a pregnancy duration of more than 20 weeks at the Enrique C. Sotomayor Obstetrics and Gynecology Hospital, Guayaquil, Ecuador, were surveyed. The questionnaire collected sociodemographic data and reasons for having inadequate prenatal care. Adequacy of prenatal care was measured with the Kessner index and correlated to the sociodemographic data.ResultsDuring the study period, 1016 pregnant women were surveyed. Among them, there were adolescents (23.7%), primigravidas (30.8%), and women with a high‐risk pregnancy (29.3%). According to the Kessner index, prenatal care was considered adequate or inadequate in 24.5% and 75.5% of cases, respectively. Knowledge regarding the importance of adequate prenatal care and the effects of poor prenatal care was lower among women who had received inadequate prenatal care. The women that were considered to have had adequate prenatal care had at least one visit, and they were more often cared for by a specialist than women who considered having inadequate prenatal care. The three most important reasons associated to inadequate prenatal care in this series (n=767), were economic difficulties having to care for a small child, and transportation difficulties. Logistic regression analysis determined that women with undesired pregnancies who resided in rural areas and were para 5 or higher had an increased risk of inadequate prenatal care. On the other hand, an adverse outcome to a prior pregnancy (abortion, intrauterine fetal demise, or ectopic pregnancy) decreased this risk. Marital status and educational level were confounding factors.ConclusionsAlthough prenatal care at our institution is free, adequacy was thought to be low. The main factors associated with poor prenatal care were mostly conditions related to poverty.
A novel method reveals that solvent water favors polyproline II over β‐strand conformation in peptides and unfolded proteins: conditional hydrophobic accessible surface area (CHASA)
Authors: Fleming Patrick J. , Fitzkee Nicholas C. , Mezei Mihaly , Srinivasan Rajgopal , Rose George D. 
Published: December 2004

AbstractIn aqueous solution, the ensemble of conformations sampled by peptides and unfolded proteins is largely determined by their interaction with water. It has been a long‐standing goal to capture these solute‐water energetics accurately and efficiently in calculations. Historically, accessible surface area (ASA) has been used to estimate these energies, but this method breaks down when applied to amphipathic peptides and proteins. Here we introduce a novel method in which hydrophobic ASA is determined after first positioning water oxygens in hydrogen‐bonded orientations proximate to all accessible peptide/protein backbone N and O atoms. This conditional hydrophobic accessible surface area is termed CHASA. The CHASA method was validated by predicting the polyproline‐II (PII) and β‐strand conformational preferences of non‐proline residues in the coil library (i.e., non‐α‐helix, non‐β‐strand, non‐β‐turn library derived from X‐ray elucidated structures). Further, the method successfully rationalizes the previously unexplained solvation energies in polyalanyl peptides and compares favorably with published experimentally determined PII residue propensities.We dedicate this paper to Frederic M. Richards.
Benchmarking B cell epitope prediction: Underperformance of existing methods
Authors: Blythe Martin J. , Flower Darren R. 
Published: December 2004

AbstractSequence profiling is used routinely to predict the location of B‐cell epitopes. In the postgenomic era, the need for reliable epitope prediction is clear. We assessed 484 amino acid propensity scales in combination with ranges of plotting parameters to examine exhaustively the correlation of peaks and epitope location within 50 proteins mapped for polyclonal responses. After examining more than 106combinations, we found that even the best set of scales and parameters performed only marginally better than random. Our results confirm the null hypothesis: Single‐scale amino acid propensity profiles cannot be used to predict epitope location reliably. The implication for studies using such methods is obvious.
The length of the reactive center loop modulates the latency transition of plasminogen activator inhibitor‐1
Authors: Na Yu‐Ran , Im Hana 
Published: December 2004

AbstractPlasminogen activator inhibitor‐1 (PAI‐1) belongs to the serine protease inhibitor (serpin) protein family, which has a common tertiary structure consisting of three β‐sheets and several α‐helices. Despite the similarity of its structure with those of other serpins, PAI‐1 is unique in its conformational lability, which allows the conversion of the metastable active form to a more stable latent conformation under physiological conditions. For the conformational conversion to occur, the reactive center loop (RCL) of PAI‐1 must be mobilized and inserted into the major β‐sheet, A sheet. In an effort to understand how the structural conversion is regulated in this conformationally labile serpin, we modulated the length of the RCL of PAI‐1. We show that releasing the constraint on the RCL by extension of the loop facilitates a conformational transition of PAI‐1 to a stable state. Biochemical data strongly suggest that the stabilization of the transformed conformation is owing to the insertion of the RCL into A β‐sheet, as in the known latent form. In contrast, reducing the loop length drastically retards the conformational change. The results clearly show that the constraint on the RCL is a factor that regulates the conformational transition of PAI‐1.
Crystal structure of the histidine‐containing phosphotransfer protein ZmHP2 from maize
Authors: Sugawara Hajime , Kawano Yoshiaki , Hatakeyama Tomomitsu , Yamaya Tomoyuki , Kamiya Nobuo , Sakakibara Hitoshi 
Published: December 2004

AbstractIn higher plants, histidine‐aspartate phosphorelays (two‐component system) are involved in hormone signaling and stress responses. In these systems, histidine‐containing phosphotransfer (HPt) proteins mediate the signal transmission from sensory histidine kinases to response regulators, including integration of several signaling pathways or branching into different pathways. We have determined the crystal structure of a maize HPt protein, ZmHP2, at 2.2 Å resolution. ZmHP2 has six α‐helices with a four‐helix bundle at the C‐terminus, a feature commonly found in HPt domains. In ZmHP2, almost all of the conserved residues among plant HPt proteins surround this histidine, probably forming the docking interface for the receiver domain of histidine kinase or the response regulator. Arg102 of ZmHP2 is conserved as a basic residue in plant HPt proteins. In bacteria, it is replaced by glutamine or glutamate that form a hydrogen bond to Nδ atoms of the phospho‐accepting histidine. It may play a key role in the complex formation of ZmHP2 with receiver domains.
Computational analysis of the transient movement of helices in sensory rhodopsin II
Authors: Sato Y. , Hata M. , Neya S. , Hoshino T. 
Published: December 2004

AbstractMD simulation of sensory rhodopsin II was executed for three intermediates (ground‐state, K‐state, M‐state) appearing in its photocycle. We observed a large displacement of the cytoplasmic side of helixF only in M‐state among the three intermediates. This displacement was transmitted to TM2, and the cytoplasmic side of TM2 rotated clockwise. These transient movements are in agreement with the results of an EPR experiment. That is, the early stage of signal transduction in a sRII–HtrII complex was successfully reproduced by the in silico MD simulation. By analyzing the structure of the sRII–HtrII complex, the following findings about the photocycle of sRII were obtained: (1) The hydrogen bonds between helixF and other helices determine the direction of the movement of helixF; (2) three amino acids (Arg162, Thr189, Tyr199) are essential for sRII–HtrII binding and contribute to the motion transfer from sRII to HtrII; (3) after the isomerization of retinal, a major conformational change of retinal was caused by proton transfer from Schiff base to Asp75, which, in turn, triggers the steric collision of retinal with Trp171. This is the main reason for the movement of the cytoplasmic side of helixF.
Effect of protease treatment on plasma infectivity in variant Creutzfeldt‐Jakob disease mice
Authors: Yakovleva Oksana , Janiak Anna , McKenzie Carroll , McShane Lisa , Brown Paul , Cervenakova Larisa 
Published: December 2004

BACKGROUND:  The emergence of variant Creutzfeldt‐Jakob disease (vCJD) and of a probable transmission of the disease through blood transfusion from a presymptomatic case has underlined the need for a reliable, sensitive, and specific screening test. This study was initiated to explain why attempts to identify protease‐resistant prion protein (PrPres) following treatment with proteinase K (PK) in blood or blood components have so far failed.STUDY DESIGN AND METHODS:  RIII mice were inoculated intracerebrally (i.c.) with vCJD agent. As soon as some mice became ill, blood from all mice was collected, pooled, and separated into components. Aliquots of plasma were treated with either 100 and 500 µg per mL PK or left untreated. Samples were analyzed for total protein and for PrPres by Western blot with 6H4 antibodies. Infectivity in PK‐treated and untreated samples was bioassayed by i.c. inoculation into healthy mice.RESULTS:  Estimated infectivity in untreated control plasma was 20.6 IU per mL. Treatment of plasma with 100 or 500 µg per mL PK resulted in estimated infectivity levels of 8.4 and 5.2 IU per mL, respectively. Coomassie staining revealed substantial changes in the protein profile after PK treatment, with massive degradation of proteins at 500 µg per mL PK. No PrPres was detected in plasma samples by Western blotting.CONCLUSION:  Infectivity in plasma of vCJD‐infected mice showed a trend toward reduction following enzymatic treatment with increasing doses of PK, possibly because of activity against proteolysis‐sensitive isoforms of abnormal prion protein. It is concluded that the use of PK in protocols for the detection of PrPres may decrease the sensitivity of blood‐based assays.