bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein‐metal ion interactions, stoichiometries and relative affinities determined by on‐line size exclusion gel filtration mass spectrometry
Authors: Benson Linda M. , Kumar Rajiv , Cavanagh John , Naylor Stephen 
Published: February 2003

AbstractThe modulation of metal ions on protein function is well recognized and of paramount importance in protein biochemistry. To date, very few methods allow direct determination of protein‐metal ion interactions, as well as exact stoichiometric binding ratios. In this work we demonstrate the usefulness of two on‐line size exclusion gel filtration mass spectrometry approaches to directly detect protein‐metal ion adducts, as well as determine exact protein‐metal ion stoichiometries. We show that on‐line size exclusion column chromatography (SEC) and rapid in‐line desalting (RILED) coupled to microelectrospray mass spectrometry (μESI‐MS) can be used for such analyses. The SEC approach can be effectively used to both separate proteins in a complex mixture and exchange buffers prior to the electrospray process. While RILED does not allow for protein separation, it provides a much faster high‐throughput desalting procedure than the conventional SEC technique. Specifically, we show that SEC/μESI‐MS and RILED/MS can be used to determine calcium ion binding stoichiometries to a high‐affinity, metal ion binding protein, calbindin D28K. Furthermore, the same approaches can also be used to determine metal ion binding stoichiometries of low‐affinity metal‐binding proteins such as Spo0F. Copyright © 2003 John Wiley & Sons, Ltd.
Analysis of unknown compounds in azithromycin bulk samples with liquid chromatography coupled to ion trap mass spectrometry
Authors: Debremaeker D. , Visky D. , Chepkwony H. K. , Van Schepdael A. , Roets E. , Hoogmartens J. 
Published: February 2003

AbstractA selective reversed‐phase liquid chromatography/mass spectrometry (LC/MSn) method is described for the identification of azithromycin impurities and related substances in commercial azithromycin samples. Mass spectral data are acquired on an LCQ ion trap mass spectrometer equipped with an atmospheric pressure chemical ionization interface operated in positive ion mode. The LCQ provides on‐line LC/MSn capability, making it ideally suited for identification purposes. In comparison with UV detection, this hyphenated technique provides as its main advantage efficient identification of novel substances without time‐consuming isolation and purification procedures. Using this technique, six novel related substances detected in commercial azithromycin samples have been studied. Copyright © 2003 John Wiley & Sons, Ltd.
New Starch Phosphate Carbamides of High Swelling Ability: Synthesis and Characterization
Authors: Heinze Ute , Klemm Dieter , Unger Ekkehard , Pieschel Friedemann 
Published: February 2003

AbstractThe paper describes the synthesis of starch phosphate carbamides by reacting starch with phosphoric acid and urea. A solid state technique in vacuum at elevated temperatures is used. The degree of substitution of phosphate (DSP) and carbamide groups (DSC) can be adjusted by the molar ratio of starch: phosphoric acid: urea, the reaction temperature, and time. The starch derivatives prepared show remarkable swelling if the DSP ranges between 0.2 and 0.3. With increasing content of urea in the reaction mixture the water‐holding ability is still significantly improved, which is explained by chemically and especially physically introduced urea into the starch polymer. Furthermore, the ratio of amylose: amylopectin of the starch samples influences both the DS values and the physicochemical properties, e.g., swelling power and multivalent metal ion adsorption of the products.The structure of the new polymers was determined by means of FTIR, 13C‐ and 31P NMR spectroscopy as well as by gel permeation chromatography (GPC).
Granule Integrity and Starch Solubility During Slow, Extended Pasting of Maize Starch — the Second Viscosity Peak
Authors: Nelles Elizabeth M. , Dewar Janice , van der Merwe Chris F. , Taylor John R. N. 
Published: February 2003

AbstractMaize starch granule integrity and starch solubilisation at specific intervals during a relatively long pasting profile—which is known to exhibit biphasic peak viscosity character—was studied by microscopy and high‐performance size‐exclusion chromatography, respectively. Maize starch granules, although swelling and leaching components, remained mainly intact until the second viscosity peak when they lost integrity and formed a relatively homogenous paste. The second viscosity peak coincided with a decrease in starch content in solution and amylose going out of solution was mainly responsible for this decrease. It is suggested that the loss of granule integrity during the second viscosity peak increases the potential for amylose to form complexes with lipids at this stage. It is further suggested that the second viscosity peak is due to the formation and breakdown of superstructures of amylose‐lipid complexes.
Material Properties and Glass Transition Temperatures of Different Thermoplastic Starches After Extrusion Processing
Authors: de Graaf Robbert A. , Karman Andre P. , Janssen Léon P. B. M. 
Published: February 2003

AbstractFour different starch sources, namely waxy maize, wheat, potato and pea starch were extruded with the plasticizer glycerol, the latter in concentrations of 15, 20 and 25% (w/w). The glass transition temperatures of the resulting thermoplastic products were measured by Dynamic Mechanical Thermal Analysis (DMTA). Beside mechanical and structural properties also the transition temperatures of the materials were evaluated during tensile and impact tests. Above certain glycerol contents, dependent on the starch source, a lower glass transition temperatureTgresulted in decreased modulus and tensile strengths and increased elongations. Lowering theTgat different glycerol contents did not influence the impact strength. When the amylose/amylopectin ratio increased a decrease inTgwas found. For pea, wheat, potato and waxy maize starch theTgwas 75 °C, 143 °C, 152 °C and 158 °C, respectively. Therefore products with higher percentages of amylose are more flexible. The shrinkage of the specimens made by injection molding was considerable compared to the specimens made by pressing.
A New Sulfato‐bridged Manganese(II) Phenanthroline Complex: [Mn(phen)(H2O)2(SO4)]
Authors: Zheng Yue‐Qing , Lin Jian‐Li 
Published: February 2003

AbstractThe sulfato bridged MnII phen complex [Mn(phen)(H2O)2SO4] (4) consists of [Mn(H2O)2(phen)(SO4)2/2] chains, which are generated from Mn atoms in distorted octahedral sites interlinked by bidentate sulfato bridges. Interdigitation of phen ligands leads to the formation of [Mn(H2O)2(phen)(SO4)2/2] double‐chains stabilized by significant π—π stacking interactions. The double‐chains are held together via interchain hydrogen bonds formed between water and sulfato O atoms. Crystal data: orthorhombic, P212121 (no. 19), a = 6.674(1), b = 10.359(1), c = 19.913(3)Å, V = 1376.7(3)Å3, Z = 4, R = 0.0439 and wR2 = 0.0935 for 1830 out of 2286 reflections with Fo2 > 2σ(Fo2).
Bildung und Kristallstruktur eines dimeren sauerstoffverbrückten Titanaminobisphenoxides
Authors: Baldamus Jens , Hecht Elmar 
Published: February 2003

Formation and Crystal Structure of an Oxygen Bridged Titanium Amino BisphenoxideDi‐(μ‐oxo)‐titan‐bis[aminobisphenoxide] (3) was obtained by reaction of (i‐Prop)2TiL* (2) {L* = O‐4, 6‐(t‐Bu)2C6H2‐2‐CH2‐[1, 4‐N2C5H10]‐2'‐CH2‐4', 6'‐(t‐Bu)2C6H2O] with water in a molar ratio 1:1 in diethylether. Both i‐Propyl moieties are substituted yielding the dimeric oxygen bridged amino bisphenoxide complex. The six coordinate Ti atoms are a result of Ti—N and Ti—O interactions of the corresponding atoms of the amino bisphenoxide ligand and the bridging O atoms. The central planar Ti2O2 ring may be considered as the general structural feature of the title compound: Space group P1¯, Z = 1, lattice dimensions at —60°C: a = 11.6899(4), b = 11.7873(4), c = 12.6462(4) Å, α = 98.070(1), β = 99.660(1), γ = 95.343(1)°, R1 = 0.0469, wR2 = 0.1049, GooF = 0.939.
Neue Gold‐Selen‐Komplexverbindungen: Synthesen und Strukturen von [Au10Se4(dpppe)4]Br2, [Au2Se(dppbe)]∞, [(Au3Se)2(dppbp)3]Cl2 und [Au34Se14(tpep)6(tpepSe)2]Cl6
Authors: Sevillano Paloma , Langetepe Timo , Fenske Dieter 
Published: February 2003

AbstractDie Umsetzung von Gold‐Phosphan‐Komplexen [(AuX)(PR3)] (X= Halogen; R = org. Rest) mit Se(SiMe3)2 führt zu neuen chalkogenoverbrückten Goldkomplexen. Durch die Verwendung mehrzähniger Phosphanliganden konnten Clusterkomplexe wie [Au10Se4(dpppe)4]Br2 (1) (dpppe = 1, 5‐Bis (diphenylphosphino)pentan), [Au2Se(dppbe)]∞ (2) (1, 4‐Bis(diphenylphosphino)benzol), [(Au3Se)2(dppbp)3]Cl2 (3) (dppbp = 4, 4′‐Bis(diphenylphosphino)biphenyl) und [Au34Se14(tpep)6(tpepSe)2]Cl6 (4) (tpep = 1, 1, 1‐Tris(diphenylphosphino)ethylphosphan, tpepSe = 1, 1‐Bis‐(di‐phenylphosphinoethyl)‐1‐(diphenylselenophosphinoethyl)phosphan) isoliert und deren Struktur mit Hilfe der Einkristallstruktur‐Analyse bestimmt werden (Strukturdaten s. Abstract).
Naphtholactam als Komplexligand
Authors: Limmert Michael , Lorenz Ingo‐Peter , Neubauer Jürgen , Schulz Axel , Piotrowski Holger 
Published: February 2003

AbstractNach Überführung des Fluorophors N‐Benz[cd]indol‐2(1H)‐on (= Naphtholactam) mit NaN(SiMe3)2 in das Naphtholactamat 1 und Umsetzung mit den Chlorokomplexen [Ph3PAuCl] und [(Ph3P)2PtCl2] entstehen die Mono‐ bzw. Disubstitutionsprodukte [Ph3PAu(C11H6NO)] (2), [(Ph3P)2PtCl(C11H6NO)] (3) und [(Ph3P)2Pt(C11H6NO)2] (4) mit einer bzw. zwei Metall‐N‐Bindungen. Bei der Umsetzung von 1 mit den Chlorophosphanen Ph3‐nPCln bilden sich die Naphtholactamato‐N‐phosphane Ph3‐nP(C11H6NO)n (n = 3 (5), 2 (6), 1 (7)), von denen sich insbesondere 7 durch Luftsauerstoff zum Phosphanoxid Ph2P(O)(C11H6NO) (8) oxidieren läßt. Die Ligandeneigenschaften der neuen Phosphane werden überprüft. Ausgehend von HAuCl4, C4H8S (= THT) und 7 entsteht der Phosphankomplex [{Ph2(C11H6NO)P}AuCl] (9). W(CO)6 setzt sich nach photolytischer CO‐Eliminierung mit 5 bzw. 7 zu den Tetracarbonyl‐Komplexen $[(CO)_{4}\overline{W\{P(C_{11}H_{6}NO)_{2}(C_{11}H_{6}NO)\}]}$/ (10) bzw. $[(CO)_{4}\overline{W\{PPh_{2}(C_{11}H_{6}NO)\}]}$/ (11) mit zweizähnig P, O‐gebundenden Naphtholactamatophosphan‐Liganden um. Die Verbindungen wurden IR‐, NMR‐ und MS‐spektroskopisch charakterisiert, 11 zusätzlich durch eine Einkristall‐Röntgenstrukturanalyse. Bei 5 wurden Berechnungen auf PM3‐Niveau zur Strukturoptimierung sowie eine NBO‐Analyse durchgeführt.
Copper(II) Polyamine Complexes with N‐Benzothiazole Sulfonamides as Counterions — Synthesis, Crystal Structures, and Properties of [Cu(dien)2](L1)2[HL1 = N‐2‐(benzothiazole)naphtalenesulfonamide, dien = diethylentriamine] and [Cu(en)2(H2O)2](L2)2[HL2 = N‐2‐(6‐chlorobenzothiazole)toluenesulfonamide, en = ethylenediamine] — Superoxide Dismutase‐like Activity
Authors: González‐Álvarez Marta , Alzuet Gloria , Borrás Joaquín , Macías Benigno , Montejo‐Bernardo Jose Manuel , García‐Granda Santiago 
Published: February 2003

AbstractCopper(II) complexes of new N‐benzothiazole sulfonamides (HL1= N‐2‐(benzothiazole)naphtalensulfonamide and HL2 = N‐2‐(6‐chlorobenzothiazole)toluenesulfonamide) with ethylenediamine (en) and diethylenetriamine (dien) have been synthesized and characterised. The crystal structures of [Cu(dien)2](L1)2 (1) and [Cu(en)2(H2O)2](L2)2 (2) compounds have been determined. The metal centre adopts a “4+2” distorted octahedral environment in both complexes. Unusually, the sulfonamidate anions act as counterions. Spectroscopic properties are in good agreement with the crystal structures. The superoxide dismutase (SOD)‐like activity of complex 2 has been tested.
Evidence of a Photo‐Radical Pathway Responsible of the Rearrangement of a Manganese(III)‐Schiff Base Complex in Solution
Authors: Maneiro Marcelino , Bermejo Manuel R. , Fernández M. Isabel , González‐Noya Ana M. , Tyryshkin Alexei M. , Pritchard Robin G. 
Published: February 2003

AbstractA new MnIII‐Schiff base complex, [MnL(OH2)](ClO4) (1) (H2L = N, N′‐bis‐(3‐Br‐5‐Cl‐salicylidene)‐1, 2‐diimino‐2‐methylethane), an inorganic model of the catalytic center (OEC, Oxygen Evolving Complex) in photosystem II (PSII), has been synthesized and characterized by elemental analysis, IR and EPR spectroscopy, mass spectrometry, magnetic susceptibility measurement and the study of its redox properties by cyclic and normal pulse voltammetry. This complex mimics reactivity (showing a relevant photolytic activity), and also some structural characteristics (parallel‐mode MnIII EPR signal from partially assembled OEC cluster) of the natural OEC. The complex 1 was found to rearrange in solution into a crystallographically solved square‐pyramidal complex, [MnLL′] (2) (HL′ = 6‐bromo‐4‐chloro‐2‐cyanophenol), through a process, which probably liberates radical species (detected by EPR), and provokes a C—N bond cleavage in the ligand. A photo‐radical mechanism is discussed to explain this rearrangement.
Synthesis, Crystal Structure and Properties of [Cu(phen)3][Cu(pheida)2]·10H2O and [(phen)2Cu(μ‐BAAP)Cu(μ‐BAAP)Cu(phen)2][Cu(BAAP)2]·8.5H2O (H2pheida = N‐phenetyl‐iminodiacetic acid, H2BAAP = N‐benzylaminoacetic‐2‐propionic acid)
Authors: Choquesillo‐Lazarte D. , Sánchez‐Moreno M.J. , Bugella‐Altamirano E. , Moyano‐Gallego M. J. , Martín‐Ramos J. D. , González‐Pérez J. M. , Carballo R. , Niclós‐Gutiérrez J. 
Published: February 2003

AbstractThe salts [Cu(phen)3][Cu(pheida)2]·10H2O (1) and [(phen)2Cu(μ‐BAAP)Cu(μ‐BAAP)Cu(phen)2][Cu(BAAP)2]·8.5H2O (2) (H2pheida = N‐phenetyl‐iminodiacetic acid, H2BAAP = N‐benzylaminoacetic‐2‐propionic acid, phen = 1, 10‐phenanthroline) have been prepared and studied by thermal, spectroscopic and X‐ray diffraction methods. 1 has the rather unusual [Cu(phen)3]2+ cation and two non‐equivalent [Cu(pheida)2]2— anions with a coordination type 4+2 but quite different tetragonality (T = 0.848 and 0.703 for anions 1 and 2, respectively). The crystal consists of multi‐π, π‐stacked chains (…anion 2 — cation — cation — anion 2…) connected by hydrophobic interactions; these chains build channels which are partially filled by anions 1 and water molecules. In contrast, compound 2 has a mixed‐ligand trinuclear cation with a bridging central moiety close similar to the counter anion. The formation of such a trinuclear cation is discussed as a consequence of the most advantageous molecular recognition process between [Cu(phen)2(H2O)1 or 2]2+ and [Cu(BAAP)2]2— in solution. In the crystal of 2, multi‐π, π‐stacked arrays of C6‐rings from phen and (BAAP)2— ligands of trinuclear cations generate channels where counter anions and water molecules are located.
Silsesquioxane Chemistry. 12 [1] Preparation and Complexation of a Novel Silsesquioxanyl Phosphine Ligand
Authors: Fei Zhaofu , Schmutzler Reinhard , Edelmann Frank T. 
Published: February 2003

AbstractThe reaction of the monofunctional closo‐silsesquioxane silanol derivative Cy7Si8O12OH (3, Cy = c‐C6H11) with tris(dimethylamino)phosphine afforded the novel silsesquioxanyl phosphine ligand Cy7Si8O12OP(NMe2)2 (4) in virtually quantitative yield. The complexes [Cy7Si8O12OP(NMe2)2]2PtCl2 (5) and [Cy7Si8O12OP(NMe2)2]2Mo(CO)4 (6) were obtained in excellent yields upon treatment of 4 with (COD)PtCl2 (COD = 1, 5‐cyclooctadiene) and (NBD)Mo(CO)4 (NBD = norbornadiene), respectively. An attempted preparation of the bis(silsesquioxanyl)phosphine (Cy7Si8O12O)2P(NMe2) led to the formation of the known disiloxane derivative (Cy7Si8O12)2O (7), instead.
Anti-parasitic effect of cyclosporin A on Echinococcus granulosus and characterization of the associated cyclophilin protein
Authors: COLEBROOK A. L. , JENKINS D. D. , LIGHTOWLERS M. W. 
Published: February 2003

Cyclophilins are a family of proteins found ubiquitously in eukaryotes, many of which bind to the immunosuppressive drug cyclosporin A (CsA). CsA has been found to have anti-parasitic effects against a variety of helminth and protozoan parasites and this activity could be mediated via cyclophilin. In this study we characterize a full length cyclophilin gene from Echinococcus granulosus, the associated natural gene and expression pattern, and investigate the functional properties of the recombinant E. granulosus cyclophilin protein. In addition, the effects of CsA were investigated on E. granulosus protoscoleces in in vitro culture. The full length E. granulosus cyclophilin cDNA encodes a protein of 20 kDa and is encoded by a single gene (EGCyP-1) comprising 2 exons separated by a 31 bp intron. The gene is expressed constitutively in all E. granulosus life-cycle stages examined. Recombinant E. granulosus cyclophilin (egCyP-1) exhibited functional enzyme activity as an isomerase. Treatment of in vitro cultures of E. granulosus protoscoleces with CsA was found to be lethal to the parasites. No protoscoleces survived treatment with 10 μg/ml of CsA over 7 culture days, as determined by observing motility and the uptake of toluidine blue dye. Untreated protoscoleces remained viable for the duration of experiments. The survival of protoscoleces was CsA dose dependent. A concentration of 10 μg/ml CsA was 100% lethal while doses of 8 μg/ml and 5 μg/ml resulted in 82% and 32% killing, respectively, after 7 days in culture. The anti-parasitic activity of CsA may have the potential to be developed as a new therapeutic agent for treatment of cystic hydatidosis in humans.
Behavioural phenotypes associated with specific genetic disorders: evidence from a population-based study of people with Prader-Willi syndrome
Authors: HOLLAND A. J. , WHITTINGTON J. E. , BUTLER J. , WEBB T. , BOER H. , CLARKE D. 
Published: February 2003

Background. Prader-Willi syndrome (PWS) is a genetic disorder resulting in obesity, short stature, cryptorchidism, learning disabilities (mental retardation) and severe neonatal hypotonia. Associated with the syndrome are a number of behaviours that are sufficiently distinctive that the syndrome is considered to have a specific ‘behavioural phenotype’.Methods. Through multiple sources we attempted to identify all people with PWS living in one region in the UK. This cohort was augmented by people with PWS from other regions, and a contrast group of people with learning disabilities of varied aetiologies. The main carers were interviewed, using structured and semi-structured interview schedules, to establish the presence and severity of specific behaviours, and PWS diagnostic criteria. The intellectual functioning and attainments of all were determined. Blood samples were obtained for genetic diagnosis from all consenting participants.Results. Although excessive eating was recognized as a potentially severe problem in those with PWS, it was almost universally controlled by food restriction, and therefore not seen as a ‘problem behaviour’. Those with PWS differed from a learning disabled group of other aetiologies in the prevalence rates of skin picking, temper tantrums, compulsive behaviours and mood fluctuations, and also in the profile of their adaptive behaviours.Conclusions. The study confirms the distinct behavioural phenotype of PWS. Specific behaviours occurred significantly more frequently in PWS, compared with an age and BMI matched learning disabled comparison group. A factor analysis of the behaviours involved resulted in three factors that we hypothesized to be independent, and to arise from different mechanisms.
Vulnerability and resiliency to suicidal behaviours in young people
Authors: FERGUSSON D. M. , BEAUTRAIS A. L. , HORWOOD L. J. 
Published: February 2003

Background. We aimed to examine factors that influence vulnerability/resiliency of depressed young people to suicidal ideation and suicide attempt.Method. Data were gathered during a 21-year longitudinal study of a birth cohort of 1265 New Zealand young people. Measures included: suicide attempt; suicidal ideation; major depression; childhood, family, individual and peer factors.Results. Young people who developed major depression had increased rates of suicidal ideation (OR=5·4; 95% CI 4·5–6·6) and suicide attempt (OR=12·1; 95% CI 7·9–18·5). However, the majority of depressed young people did not develop suicidal ideation or make suicide attempts, suggesting that additional factors influence vulnerability or resiliency to suicidal responses. Factors influencing resiliency/vulnerability to suicidal responses included: family history of suicide; childhood sexual abuse; neuroticism; novelty seeking; self-esteem; peer affiliations; and school achievement. These factors operated in the same way to influence vulnerability/resiliency among those depressed and those not depressed.Conclusions. Vulnerability/resiliency to suicidal responses among those depressed (and those not depressed) is influenced by an accumulation of factors including: family history of suicide, childhood sexual abuse, personality factors, peer affiliations and school success. Positive configurations of these factors confer increased resiliency, whereas negative configurations increase vulnerability.
Insight: its relationship with cognitive function, brain volume and symptoms in schizophrenia
Authors: ROSSELL S. L. , COAKES J. , SHAPLESKE J. , WOODRUFF P. W. R. , DAVID A. S. 
Published: February 2003

Background. Lack of insight is frequently observed in schizophrenia. Relationships have been noted between poor insight, clinical symptoms and cognitive impairments but the findings are inconsistent. There have been some recent attempts to relate poor insight to neuro-anatomical measures.Method. We assessed insight, positive and negative symptoms of schizophrenia, cognitive performance, and whole brain volumes in a sample of 78 DSM-IV male schizophrenics and 36 normal male comparison subjects matched for age and IQ. Subjects underwent a dual-echo MRI brain scan to establish grey, white and whole brain volumes.Results. Poor Wisconsin Card Sorting Test performance inversely correlated with insight in schizophrenic patients, as did the symptoms alogia, anhedonia, avolition/apathy, affective flattening, inappropriate affect, thought disorder and delusions. The presence of inappropriate affect, delusions and thought disorder, showed the most significant impact on insight levels. There were no significant correlations between whole brain, white and grey matter volume and degree of insight.Conclusions. The results suggest that poor insight is significantly related to schizophrenic psychopathology, and confirm that there is a relationship between insight and executive performance. Awareness of illness is not related to any global brain measures, suggesting future investigations should pay attention to more specific cortical regions such as the frontal cortex.