bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Sr3N)E and (Ba3N)E (E = Sb, Bi): Synthesis, Crystal Structures, and Physical Properties
Authors: Gäbler Frank , Kirchner Martin , Schnelle Walter , Schwarz Ulrich , Schmitt Miriam , Rosner Helge , Niewa Rainer 
Published: October 2004

AbstractSingle phase powders of (Sr3N)Sb, (Sr3N)Bi ($Pm{\bar 3}m$, No. 221, Z = 1, Sb: a = 517.25(2) pm, V = 138.390(8) · 106 pm3, Bi: a = 520.691(8) pm, V = 141.170(4) · 106 pm3), (Ba3N)Sb, and (Ba3N)Bi (P63/mmc, No. 194, Z = 2, Sb: a = 753.33(3) pm, c = 664.45(3) pm, V = 326.56(2) · 106 pm3, Bi: a = 761.28(4) pm, c = 668.05(3) pm, V = 335.30(2) · 106 pm3) were obtained from reactions of melt beads of the respective elements with bulk compositions of A3E (A = Sr, Ba; E = Sb, Bi) in nitrogen atmosphere of ambient pressure at T = 1070 K (Sr) and T = 1120 K (Ba). The compositions were derived from chemical analyses and supported by Rietveld refinements based on powder X‐ray diffraction patterns. The Sr containing compounds crystallize in the cubic anti‐perovskite type arrangement, the Ba containing compounds in the hexagonal anti‐BaNiO3 structure type. Magnetic susceptibility and electrical resistivity data indicate that the compounds are diamagnetic semiconductors. The optical band gaps of (Sr3N)Sb and (Sr3N)Bi were determined by diffuse reflectivity to 1.15 eV and 0.89 eV, respectively. The experimental results are in agreement with electronic structure calculations. Chemical bonding is characterized in a simplified picture as ionic with significant orbital mixing.
Neue Arsenide mit As‐‐Ketten und ‐Ringen: BaAs2 und AIBa2As5 (AI = K, Rb)
Authors: Emmerling Franziska , Petri Denis , Röhr Caroline 
Published: October 2004

AbstractDie drei Titelverbindungen, die aus den Elementen synthetisiert wurden, sind Vertreter klassischer Zintlphasen mit Chalkogen‐isosteren As‐‐Anionen. In BaAs2 (monoklin, Raumgruppe Pc, a = 655.0(2), b = 1253.2(4), c = 803.8(3) pm, β = 127.75(2)°, R1=0.0639) liegen Kettenanionen in zwei unterschiedlichen Konformationen vor, die sich wiederum von den As‐Ketten in der Struktur von KBa2As5 (orthorhombisch, Raumgruppe Cmc21, a = 787.2(3), b = 1052.9(4), c = 1177.0(4) pm, R1 = 0.0319) unterscheiden. Dagegen enthält RbBa2As5 (trigonal, Raumgruppe P3121, a = 778.4(2), c = 1430.9(4) pm, R1 = 0.0654) gewellte Fünfringe As55‐. Die für die Bildung von Ringen bzw. unterschiedlichen Ketten relevanten Parameter werden auf der Basis von Geometrieanalysen und Berechnungen der elektronischen Strukturen diskutiert.
Ba8Ge43 revisited: a 2a′×2a′×2a′ Superstructure of the Clathrate‐I Type with Full Vacancy Ordering
Authors: Carrillo‐Cabrera Wilder , Budnyk Serhij , Prots Yurii , Grin Yuri 
Published: October 2004

AbstractThe reinvestigation of the crystal structure of Ba8Ge43□3 (space group $Ia{\bar 3}d$, no. 230; a = 21.3123(5) Å; Z = 8; Pearson symbol cI408) shows a full ordering of the vacancies (□) in the germanium framework. This ordered crystal structure can be considered as a derivative of an ideal “Ba8Ge46” clathrate‐I type structure ($Pm{\bar 3}n$, a′ = a/2) in which three Ge vacancies (per formula unit) are allowed to order in a cubic superstructure with a doubled unit cell parameter (□ at the 24c site, space group $Ia{\bar 3}d$). In the resulting Ge framework, each vacancy □ is surrounded by four three‐bonded (3b)Ge‐ species. The ordering in crystals of as‐cast samples (cooled in argon atmosphere, non‐annealed) is partially disrupted. For the “as‐cast” crystals, a short‐range model is proposed based on the partial distribution of Ge on the 24c and 24d sites. From the electron balance, Ba8Ge43 can be considered as a metallic Zintl phase with four excess electrons per formula unit. The Ba8Ge43 phase is stable in the temperature range 770 ‐ 810 °C and exists in equilibrium with Ba6Ge25 and Ge. By decomposition of undercooled (metastable) Ba8Ge43, a new metastable binary BaGe˜5 phase is formed.
Ca[Cu(C2H)3] · 6 NH3 und Rb2[Cu(C2H)3] · NH3: Zwei Ethinylocuprate mit einem trigonal planaren [Cu(C2H)3]2‐‐Anion
Authors: Cremer Ulrich , Disch Sabrina , Ruschewitz Uwe 
Published: October 2004

AbstractDurch Umsetzungen in flüssigem Ammoniak wurden Ca[Cu(C2H)3] · 6 NH3 und Rb2[Cu(C2H)3] · NH3 in polykristalliner Form erhalten. Die Verbindungen verlieren leicht Ammoniak und sind bei Zimmertemperatur nur in einer NH3Atmosphäre stabil. Strukturuntersuchungen auf der Grundlage von Röntgenpulverdaten ergaben hexagonale Elementarzellen (Ca[Cu(C2H)3] · 6 NH3: P63mc, Z = 2, a = 986, 39(1) pm, c = 926, 47(1) pm; Rb2[Cu(C2H)3] · NH3: P63/m, Z = 6, a = 1096, 46(2) pm, c = 1600, 15(3) pm). Nahezu planare trigonale [Cu(C2H)3]2‐‐Baugruppen sind das charakteristische Strukturmerkmal, die im Falle der Calciumverbindung von [Ca(NH3)6]2+‐Oktaedern separiert werden. Das Motiv der Anordnung der komplexen Kat‐ und Anionen ist analog zum hexagonalen BN. Die Kristallstruktur vonRb2[Cu(C2H)3] · NH3 ist durch Säulen flächenverknüpfter Rb6‐Polyeder entlang [001] charakterisiert, die entweder mit [Cu(C2H)3]2‐‐Anionen oder drei NH3‐Molekülen gefüllt sind. Senkrecht dazu sind die Stränge über gemeinsame Kanten verknüpft, so dass sich das Motiv eines dreidimensionalen Netzwerks ergibt. Eine analoge Caesiumverbindung konnte ebenfalls dargestellt werden, wie Raman‐Spektren belegen. Allerdings ist diese Verbindung so empfindlich, dass eine vollständige strukturelle Charakterisierung nicht möglich war.
Novel Combination of Coordination Polyhedra in Mg2Co3Sn10+x ‐ The First Phase in the Mg/Co/Sn System
Authors: Schreyer Martin , Kraus Günther , Fässler Thomas F. 
Published: October 2004

AbstractMg2Co3Sn10+x is the first compound in the ternary system Mg/Co/Sn. Single crystals for structure analysis were grown from the elements by a tin flux method. The structure (P63/mmc, a = 9.490(1) Å and c = 33.555(7) Å) was determined by X‐ray single crystal analysis (R1 = 0.037). A small phase width of 0 ≤ x ≤ 0.15, due to the partial occupancy of one out of ten tin positions is observed. There are two crystallographically different cobalt sites each with a unique tin coordination sphere. The Co1 site has a square antiprismatic coordination with tin atoms comparable to the ones observed in the tin rich binary stannides. The Co2 site is characterized by a trigonal prismatic coordination with tin similar to previously known ternary stannides. The different polyhedra are arranged in alternating layers in an intricate way which gives rise to tin‐tin distances shorter than 3Å. Magnesium is only found in those layers which have cobalt trigonal prismatically coordinated to tin atoms. Thus, the structure shows an unprecedented arrangement of different coordination spheres, and furthermore provides evidence for homoatomic tin bonding within a metallic framework. Magnetic susceptibility measurements show temperature independent Pauli‐paramagnetism down to 50 K.
The First Reduced Rare Earth Halide with a Group 11 Element as Interstitial: La3I3Au
Authors: Mattausch Hansjürgen , Zheng Chong , Kienle Lorenz , Simon Arndt 
Published: October 2004

AbstractThe title compound was synthesized from La, LaI3 and Au under Ar atmosphere in the temperature range 850‐950 °C. It crystallizes in the cubic space group I4132 with lattice constant a = 12.661(2) Å. The structure features Au‐centered helical octahedron chains arranged in all three directions with 90 degree turns. It is the first reduced rare earth halide with a group 11 interstitial. It is very air and moisture sensitive, and produces crimson‐colored Au precipitate similar to Gold Purple of Cassius upon reaction with water or ethanol.
New Oxovanadium(IV) Complexes with Mixed Ligands ‐ Synthesis, Thermal Stability, and Crystal Structure of (VO)2(acac)2(μ‐OEt)2 and (VO)2(thd)2(μ‐OEt)2
Authors: Ahmed M. A. K. , Fjellvåg H. , Kjekshus A. , Klewe B. 
Published: October 2004

AbstractSynthesis, crystal structure, thermal stability, and magnetic properties of the new oxovanadium(IV) complexes [(VO)2L2(μ‐OEt)2] with mixed β‐diketonato [L = acac = C5H7O2‐ or L = thd = C11H19O2‐] and ethanolato (OEt) ligands are reported. The structure determinations of (VO)2(acac)2(μ‐OEt)2 [P21/c, with a = 14.775(2), b = 8.788(1), c = 15.742(2) Å, β = 112.43(1)°] and (VO)2(thd)2(μ‐OEt)2 [$P{\bar 1}$, with a = 8.871(3), b = 9.988(4), c = 10.299(4) Å, α = 73.51(1), β = 68.70(1), γ = 65.85(1)°] are based on single‐crystal X‐ray diffraction data collected at 105 K. Structure data for VO(acac)2 and VO(thd)2 are redetermined at 105 and 295 K. (VO)2(acac)2(μ‐OEt)2 and (VO)2(thd)2(μ‐OEt)2 comprise binuclear five‐coordinated molecular units. The configuration of five oxygen atoms around a central vanadium atom is approximately square pyramidal in all the four studied complexes. (VO)2(thd)2(μ‐OEt)2 exhibits conspicuous changes in unit‐cell dimensions (expansion in a and c, shrinkage in b, and appreciable variation in α, β, and γ) on going from 105 to 295 K, which appear to reflect adjustments in the configuration of its (anti‐arranged) ligands. The interatomic distances in the crystal structures are analyzed in terms of the bond‐valence concept. The four‐valent state of vanadium is verified by magnetic susceptibility measurements. All complexes are subject to sublimation.
Automatic measurement of particulate contaminants (dirts) in cotton linters
Authors: Smith J. W. , Ferguson G. N. , Mills J. D. 
Published: October 2004

AbstractAn electronic image scanning measurement method was developed to obtain objective measurements of the area of resistant dark contaminants, broadly referred to as dirts, contained in cottonseed linters and hull fibers. The method is based upon the use of the AOCS standard cellulose yield residue. The yield residue (20 g) was bleached and formed into a 10 × 12 in. test sheet, and the projected area of visible dirts in 42 fields on each side of the sheet was meausred. Areas as small as 0.1 mm2 in a field 30 × 41 mm can be measured. The results were converted to area, summed, and compared with the visual measurements obtained using the method of Jurbergs and Dowling. Statistical analysis gave standard deviations of ca. 8% and 25%, respectively, for new and the earlier procedures. The instrument standard deviation was shown to be ca. 1% relative. A comparison of the two methods using samples of 1099 different lots of linters gave a 0.94 correlation coefficient.
Lubricants and lubricant additives: I. Performance characteristics of N‐mono and N,N‐Disubstituted fatty amides and modified fatty amides
Authors: Magne F. C. , Mod R. R. , Sumrell G. , Parker W. E. , Koos R. E. 
Published: October 2004

AbstractA number of N‐mono and N,N‐disubstituted amides of substituted and unsubstituted C18 fatty acids have been prepared and evaluated as base lubricants and lubricant additives. The neat epithioamides possess extreme pressure lubricant characteristics and are noncorrosive at normal temperatures. The epithioamides also frequently function as extreme pressure additives and antiwear agents for paraffinic or diester base oils, sometimes in both capacities for both base oils. The intensiveness of these properties correlated directly with the degree of thiirane substitution in the compound. Performance in both these capacities at the same levels of epithioation was dependent upon the N‐ or N,N‐substituent groups present.
Rapid and nondestructive determination of seed oil by pulsed nuclear magnetic resonance technique
Authors: Tiwari P. N. , Gambhir P. N. , Rajan T. S. 
Published: October 2004

AbstractThe pulsed NMR technique for rapid and nondestructive determination of oil in oilseeds has been developed. The effects of spin‐lattice relaxation time, spin‐spin relaxation time, seed moisture, angular position of the seeds, sample tube thickness, and sample height upon the magnitude and reproducibility of the NMR signal were studied. Based upon these studies, various parameters for seed oil analysis have been fixed. The oil content of Brassica, peanut, and sunflower seeds was determined. The reproducibility of the measurement is ± 1 %. The technique was tested by measuring the oil content of the same seeds by the cold percolation method (CCl4 extraction). It was further tested by determining the oil content of 60 Brassica seed samples independently at three laboratories. The results of these tests are given.
Excitotoxicity and bioenergetics in glutaryl‐CoA dehydrogenase deficiency
Authors: KÖlker S. , Koeller D. M. , Sauer S. , HÖrster F. , Schwab M. A. , Hoffmann G. F. , Ullrich K. , Okun J. G. 
Published: October 2004

AbstractSummary: Glutaryl‐CoA dehydrogenase deficiency is an inherited organic acid disorder with predominantly neurological presentation. The biochemical hallmark of this disease is an accumulation and enhanced urinary excretion of two key organic acids, glutaric acid and 3‐hydroxyglutaric acid. If untreated, acute striatal damage is often precipitated by febrile illnesses during a vulnerable period of brain development in infancy or early childhood, resulting in a dystonic dyskinetic movement disorder. 3‐Hydroxyglutaric and glutaric acids are structurally similar to glutamate, the main excitatory amino acid of the human brain, and are considered to play an important role in the pathophysiology of this disease. 3‐Hydroxyglutaric acid induces excitotoxic cell damage specifically via activation of N‐methyl‐D‐aspartate receptors. It has also been suggested that secondary amplification loops potentiate the neurotoxic properties of these organic acids. Probable mechanisms for this effect include cytokine‐stimulated NO production, a decrease in energy metabolism, and reduction of cellular creatine phosphate levels. Finally, maturation‐dependent changes in the expression of neuronal glutamate receptors may affect the vulnerability of the immature brain to excitotoxic cell damage in this disease.
Maintenance treatment of glutaryl‐CoA dehydrogenase deficiency
Authors: Mühlhausen C. , Hoffmann G. F. , Strauss K. A. , KÖlker S. , Okun J. G. , Greenberg C. R. , Naughten E. R. , Ullrich K. 
Published: October 2004

AbstractSummary: This paper summarizes the published experience as well as results of the 3rd International Workshop on Glutaryl‐CoA Dehydrogenase Deficiency held in October 2003 in Heidelberg, Germany, on the topic treatment of patients with glutaryl‐CoA dehydrogenase (GCDH) deficiency. So far no international recommendation for treatment of GCDH deficiency exists. Such an approach is hampered by several facts, namely the lack of an in‐depth understanding of the pathophysiology of the disease, the lack of prospective studies, including the evaluation of drug monotherapy, and lack of objective documentation of clinical changes (e.g. video documentation) during pharmacotherapy.
Looking forward—An evidence‐based approach to glutaryl‐CoA dehydrogenase deficiency
Authors: KÖlker S. , Burgard P. , Okun J. G. , Schulze‐Bergkamen A. , Assmann B. , Greenberg C. R. , Hoffmann G. F. 
Published: October 2004

AbstractSummary: Three decades after the first description of glutaryl‐CoA dehydrogenase deficiency, major progress has been achieved in the prevention of acute striatal necrosis and neurological sequelae in affected children, if diagnosis is made early and treatment is started before manifestation of acute encephalopathic crises. However, all concepts for diagnostic work‐up, monitoring, and treatment are solely experience‐based, and 10–35% of early‐diagnosed children do not or only incompletely benefit from the current management. They still develop neurological deterioriation and sequelae despite early implementation of dietary treatment, carnitine supplementation and emergency treatment during acute intercurrent illnesses. International efforts should be made to move management of affected children from experience‐based to evidence‐based medicine. Major tools for this optimization are the establishment of an international patients' database, the implementation of an international prospective clinical study, and the development of international guidelines for diagnostic work‐up, monitoring and therapy.
Isobutyryl‐CoA dehydrogenase deficiency: Isobutyrylglycinuria and ACAD8 gene mutations in two infants
Authors: Sass J. O. , Sander S. , Zschocke J. 
Published: October 2004

AbstractSummary: Isobutyryl‐CoA dehydrogenase (IBD) is an enzyme involved in the catabolism of the branched‐chain amino acid valine. We report a third and a fourth child with IBD deficiency who were both detected during newborn screening with tandem mass spectrometry and so far do not receive any treatment. The diagnosis was confirmed by biochemical and molecular studies. One of the children is homozygous for the mutation M128I in the ACAD8 gene, which is predicted to affect the substrate binding cavity. The other child is compound heterozygous for a frameshift mutation F33fsins and a missense mutation V203I. It is as yet uncertain whether IBD deficiency may cause significant morbidity in affected children and whether treatment is necessary. In view of the limited experience worldwide, careful monitoring of the children is recommended.
Molecular basis of hypoxanthine‐guanine phosphoribosyltransferase deficiency in Italian Lesch‐Nyhan patients: Identification of nine novel mutations
Authors: Bertelli M. , Randi D. , Micheli V. , Gallo S. , Andrighetto G. , Parmigiani P. , Jacomelli G. , Carella M. , Lievore C. , Pandolfo M. 
Published: October 2004

AbstractSummary: Lesch‐Nyhan syndrome (LSN, McKusick 300322) is an X‐linked genetic disease due, in its typical form, to the complete absence of hypoxanthine‐guanine phosphoribosyltransferase (HPRT, EC 2.4.2.8) enzyme activity. It is characterized by hyperuricaemia, leading to gout and kidney stones, accompanied by severe neurological dysfunction with self‐injurious behaviour, choreoathetosis and spasticity. Based on a worldwide birth incidence estimate of about 1:380000, one or two new cases are expected every year in Italy. We performed biochemical and molecular genetic studies on 28 Italian patients from 25 families who are likely to represent most living individuals with the syndrome in the country. They all had absent HPRT activity and a typical LNS phenotype. Genetic analysis identified 24 HPRT mutations, 9 of which had not been previously reported: 74C>G (P25R), IVS2+1G>C, 194‐195delTC, 329‐332delCAAC insTCTs, IVS9‐1G>A, 506insC, IVS8‐1G>C, 606G>T (L202F), 418G>C (G140R). No mutation hotspots were identified. Only two mutations were found in more than one family, indicating the lack of any major mutation causing LNS in Italy. Three mutations arose de novo, two in the proband's mother, one in the maternal grandmother. The virtual complete absence of HPRT activity was related to deletions, nonsense, or missense mutations leading to nonconservative amino acid changes.
Carnitine transporter defect due to a novel mutation in the SLC22A5 gene presenting with peripheral neuropathy
Authors: Makhseed N. , Vallance H.D. , Potter M. , Waters P.J. , Wong L.T.K. , Lillquist Y. , Pasquali M. , Filippo C. Amat di San , Longo N. 
Published: October 2004

AbstractSummary: The carnitine transporter defect (McKusick 212140) is an autosomal recessive disorder caused by mutations in the SLC22A5 gene, which encodes the high‐affinity carnitine transporter OCTN2 (Wang et al 2001). Diagnosis is suspected when plasma carnitine levels are extremely low and secondary causes of carnitine loss are excluded. The disease can present with recurrent Reye‐like episodes of hypoketotic hypoglycaemia or with cardiomyopathy associated with myopathy (Stanley et al 1991). Here we report novel clinical findings in a 3‐year‐old with primary carnitine deficiency.
Staphylococcus aureus DNA ligase: characterization of its kinetics of catalysis and development of a high-throughput screening compatible chemiluminescent hybridization protection assay
Authors: GUL Sheraz , BROWN Richard , MAY Earl , MAZZULLA Marie , SMYTH Martin G. , BERRY Colin , MORBY Andrew , POWELL David J. 
Published: October 2004

DNA ligases are key enzymes involved in the repair and replication of DNA. Prokaryotic DNA ligases uniquely use NAD+ as the adenylate donor during catalysis, whereas eukaryotic enzymes use ATP. This difference in substrate specificity makes the bacterial enzymes potential targets for therapeutic intervention. We have developed a homogeneous chemiluminescence-based hybridization protection assay for Staphylococcus aureus DNA ligase that uses novel acridinium ester technology and demonstrate that it is an alternative to the commonly used radiometric assays for ligases. The assay has been used to determine a number of kinetic constants for S. aureus DNA ligase catalysis. These included the Km values for NAD+ (2.75±0.1 μM) and the acridinium-ester-labelled DNA substrate (2.5±0.2 nM). A study of the pH-dependencies of kcat, Km and kcat/Km has revealed values of kinetically influential ionizations within the enzyme–substrate complexes (kcat) and free enzyme (kcat/Km). In each case, the curves were shown to be composed of one kinetically influential ionization, for kcat, pKa=6.6±0.1 and kcat/Km, pKa=7.1±0.1. Inhibition characteristics of the enzyme against two Escherichia coli DNA ligase inhibitors have also been determined with IC50 values for these being 3.30±0.86 μM for doxorubicin and 1.40±0.07 μM for chloroquine diphosphate. The assay has also been successfully miniaturized to a sufficiently low volume to allow it to be utilized in a high-throughput screen (384-well format; 20 μl reaction volume), enabling the assay to be used in screening campaigns against libraries of compounds to discover leads for further drug development.
Diminished synthesis of subunit a (ATP6) and altered function of ATP synthase and cytochrome c oxidase due to the mtDNA 2 bp microdeletion of TA at positions 9205 and 9206
Authors: JEŠINA Pavel , TESAŘOVÁ Markéta , FORNŮSKOVÁ Daniela , VOJTÍŠKOVÁ Alena , PECINA Petr , KAPLANOVÁ Vilma , HANSÍKOVÁ Hana , ZEMAN Jiří , HOUŠTĚK Josef 
Published: October 2004

Dysfunction of mitochondrial ATPase (F1Fo-ATP synthase) due to missense mutations in ATP6 [mtDNA (mitochondrial DNA)-encoded subunit a] is a frequent cause of severe mitochondrial encephalomyopathies. We have investigated a rare mtDNA mutation, i.e. a 2 bp deletion of TA at positions 9205 and 9206 (9205ΔTA), which affects the STOP codon of the ATP6 gene and the cleavage site between the RNAs for ATP6 and COX3 (cytochrome c oxidase 3). The mutation was present at increasing load in a three-generation family (in blood: 16%/82%/&gt;98%). In the affected boy with severe encephalopathy, a homoplasmic mutation was present in blood, fibroblasts and muscle. The fibroblasts from the patient showed normal aurovertin-sensitive ATPase hydrolytic activity, a 70% decrease in ATP synthesis and an 85% decrease in COX activity. ADP-stimulated respiration and the ADP-induced decrease in the mitochondrial membrane potential at state 4 were decreased by 50%. The content of subunit a was decreased 10-fold compared with other ATPase subunits, and [35S]-methionine labelling showed a 9-fold decrease in subunit a biosynthesis. The content of COX subunits 1, 4 and 6c was decreased by 30–60%. Northern Blot and quantitative real-time reverse transcription–PCR analysis further demonstrated that the primary ATP6 – COX3 transcript is cleaved to the ATP6 and COX3 mRNAs 2–3-fold less efficiently. Structural studies by Blue-Native and two-dimensional electrophoresis revealed an altered pattern of COX assembly and instability of the ATPase complex, which dissociated into subcomplexes. The results indicate that the 9205ΔTA mutation prevents the synthesis of ATPase subunit a, and causes the formation of incomplete ATPase complexes that are capable of ATP hydrolysis but not ATP synthesis. The mutation also affects the biogenesis of COX, which is present in a decreased amount in cells from affected individuals.