bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical energies of representative carbon–carbon bonds
Authors: Barone Vincenzo , Fliszár Sándor 
Published: January 2005

AbstractA bond‐energy formula deduced by means of the Hellmann–Feynman theorem is applied to selected simple hydrocarbons. The required potentials at the nuclei are calculated with the help of large basis‐set expansions including polarization functions. The carbon–carbon bond energy of ethane is evaluated at ∼ 70 kcal mol−1. TheCCbond energies of ethane, ethylene, acetylene, benzene, and cyclopropane are approximately in a ratio of 1: 2.0: 3.0: 1.65 1.0. Limitations and possible improvements in future applications of this energy formula are discussed. © 1995 John Wiley & Sons, Inc.
An atomic interaction energy approach to the reactivity of the aromatic ring toward electrophilic attack
Authors: Yu Zhong‐Heng 
Published: January 2005

AbstractA procedure of constructing a complete fragment orbital basis set is described in detail. It provides a complete fragment orbital basis for PMO analysis of the atomic interaction energy. Rt values, a ratio of the bonded atomic interaction energy to the nonbonded interaction energy arising from the peripheral atoms of the aromatic rings, indicate a decrease in the reactivity of the aromatic ring toward electrophilic attack in the sequence: pyrrole > imidazole > furan > pyrazine > pyrimidine > aniline > benzene > pyridine > p‐acylaniline > p‐cyanoaniline > p‐nitroaniline > m‐cyanoaniline. © 1995 John Wiley & Sons, Inc.
Über die Bildung von Hyponitrit durch Disproportionierung des Hydroxylamins
Authors: Nast R. , Föppl I. 
Published: January 2005

AbstractEs wird eine neue Bildungsweise für Hyponitrite beschrieben, die primär auf eine Disproportionierung des Hydroxylamins in NH3 und HNO zurückgeht, wobei Nitroxyl sich teilweise zu Hyponitrit dimerisiert. Es wird ferner gezeigt, daß die Entstehung aller wesentlichen Zersetzungsprodukte des Hydroxylamins auf Folgereaktionen primär gebildeten Nitroxyls zurückzuführen sind.
Beitrag zur Kristallchemie komplexer Wismutchalkogenverbindungen
Authors: Gattow G. , Zemann J. 
Published: January 2005

AbstractLiBiS2, NaBiSe2 und KBiSe2 kristallisieren im NaCl‐Typ mit statistischer Alkali‐ und Wismutverteilung. Die Gitterkonstanten sind: LiBiS2: a = 5,603 Å, NaBiSe2: a = 5,852 Å, KBiSe2: a = 5,922 Å.
Wasserstoffverbindungen von Schwermetallen. II. Zur Darstellung von Schwermetall‐Wasserstoff‐Verbindungen nach der Methode von SCHLENK und WEICHSELFELDER
Authors: Sarry Brigitte 
Published: January 2005

AbstractEs werden die Bedingungen untersucht, unter denen eine vollständige Umsetzung von Schwermetallchloriden mit Phenylmagnesiumbromid und Wasserstoff möglich ist, und die Abweichungen der eigenen Beobachtungen von den Ergebnissen von SCHLENK und WEICHSELFELDER begründet.
Über Metallcarbonyle. 68. Die Basenreaktion des Chromhexacarbonyls
Authors: Hieber W. , Abeck W. , Platzer H. K. 
Published: January 2005

AbstractDie Basenreaktion des Chromhexacarbonyls führt unter Verwendung alkoholischer Alkalilauge bei höherer Temperatur zur Entstehung von 1 Mol Carbonat pro Metallatom (I), jedoch wird bereits im alkalischen System allmählich 1 Mol Wasserstoff pro Chromatom frei (II). Die Reaktion läßt sich in Anlehnung an die Basenreaktion des Fe(CO)5 durch das intermediäre Auftreten labiler Carbonylchromat‐Anionen erklären:

equation image

Unter weiterem Abbau von Kohlenoxyd, das mit der alkoholischen Lauge unter Formiatbildung reagiert, entsteht gelbes Hydroxo‐diaquo‐tricarbonyl‐chromat (0) (III), das im allgemeinen im Gleichgewicht mit dem roten Triaquokomplex vorliegt:

equation image
.
Über fluorhaltige Verbindungen der Elemente der V. Hauptgruppe. I. Das [AsCl4]+[AsF6]−
Authors: Kolditz Lothar 
Published: January 2005

AbstractDurch Einleiten von Chlor in Arsentrifluorid bei 0° C entsteht eine kristalline Substanz mit einem Atom‐Verhältnis von As:Cl:F = 1:2:3. Sie ist in Arsentrifluorid gut löslich und fällt bei Überschuß an AsF3 erst nach längerer Zeit aus, wenn die Sättigungskonzentration der sich langsam bildenden Verbindung in AsF3 als Lösungsmittel erreicht ist. In der neuen Verbindung ist das Fluor so fest an Arsen gebunden, daß zur quantitativen Bestimmung ein Aufschluß mit metallischem Natrium erforderlich ist. Es wird chemisch bewiesen, daß der Substanz die Struktur [AsCl4]+[AsF6]− zukommt. In Arsentrifluorid zeigt [AsCl4]+[AsF6]− elektrolytische Leitfähigkeit.
Beitrag zur Kenntnis des Silber(II)‐oxyds
Authors: Schwab Georg‐Maria , Hartmann Guido 
Published: January 2005

AbstractDurch DEBYE‐SCHERRER‐Aufnahmen wie durch Messung der katalytischen Wirksamkeit und ihrer Temperaturabhängigkeit gegenüber dem Ozonzerfall wird gezeigt, daß die durch Oxydation von Silber und Silber(I)‐oxyd, durch Zersetzung von Ag7NO11 und durch Peroxydisulfat‐oxydation von Ag+ erhältlichen Oxyde identisch mit Silber(II)‐oxyd sind.
Zur Kenntnis der Chemie der Metallcarbonyle in flüssigem Ammoniak. I. Über die Reaktionen der Carbonyle des Eisens und Kobalts mit Alkalimetallen
Authors: Behrens H. , Weber R. 
Published: January 2005

AbstractDie monomeren und mehrkernigen reinen Carbonyle des Eisens und Kobalts lassen sich durch Lösungen von Alkalimetallen in flüssigem Ammoniak leicht zu den betreffenden Carbonylmetallaten reduzieren. Die Reaktionen werden durch Bestimmung der verbrauchten Alkalimetallmengen, der gebildeten Carbonylmetallate sowie der bei den Reaktionen freiwerdenden Gase quantitativ untersucht.
Titanium salts of mono‐carboxylic acids. I. Attempted Preparation of Titanium Tetra‐Soaps
Authors: Pande K. C. , Mehrotra R. C. 
Published: January 2005

AbstractWith a view to prepare the tetra‐soaps of titanium, the reaction between titanium alkoxides and excess of various fatty acids has been studied in refluxing benzene. The alcohol produced was removed azeotropically with the solvent. However, all the four alkoxy groups per titanium atom could not be replaced in any of the experiments. Even on carrying out the reaction in a higher boiling solvent like toluene, similar results were obtained and only 3 moles of alcohol per mole of the alkoxide could be azeotropically distilled out. It has been shown that the fourth alkoxy group is held in such a manner that it cannot be displaced even on refluxing the reaction product with higher alcohols or water. On heating the product to about 200° under reduced pressure, the excess fatty acid which distilled out has been shown to be mixed with some ester and the residue was found to be a decomposed titanium soap of the type TiOx(OOCR)4−2x with the value of ‘x’ nearly 0.5. These observations have been explained either by the steric hindrance to the entry of the fourth acid group or by the occurrence of other side reactions with the formation of organic ester.
Magnetochemische Untersuchungen an Metallcarbonylkomplexen
Authors: Hieber W. , Floss J. G. 
Published: January 2005

AbstractFür eine Reihe von substituierten Metallcarbonylverbindungen, namentlich der Edelmetalle Ruthenium und Rhodium, konnte auf Grund der magnetischen Eigenschaften ihre Konstitution als Molekülkomplexe bestätigt und ihre Bindungsfunktionen festgelegt werden.Insbesondere war es ferner möglich, die salzartige Konstitution von Produkten der Reaktion von Eisen‐ und Mangancarbonylen mit N‐ und O‐Basen, die in letzter Zeit mehrfach diskutiert wurden, eindeutig zu beweisen. Die Anionen [Fe(CO)4]2−, [Fe2(CO)8]2−, [Fe3(CO)11]2−, [Fe4(CO)13]2−, sowie das [Mn(CO)5]− erweisen sich als diamagnetisch, während ihre Verbindungen mit paramagnetischen Komplexkationen das bekannte Moment derselben zeigen.Ebenso wurde bei CO‐haltigen Rheniumverbindungen deren salzartige Struktur mit CO‐haltigem Kation bestätigt.
Über Lithium‐ und Natriumuranat(V)
Authors: Rüdorff W. , Leutner H. 
Published: January 2005

AbstractBei der Umsetzung von Lithium‐ bzw. Natriummonouranat(VI) mit UO2 entstehen die beständigen Uranate (V), LiUO3 bzw. NaUO3. Die entsprechende Kaliumverbindung konnte nicht erhalten werden.
Über Nickel–Zink‐Mischoxalatkontakte
Authors: Welker J. 
Published: January 2005

AbstractDurch Zersetzung von Nickeloxalat–Zinkoxalat‐Mischkristallen im Wasserstoffstrom werden Katalysatoren erhalten, die sich bei Reaktionen in der Gasphase durch hohe Aktivität auszeichnen. Die Hydrierung von Aceton und Benzol verläuft schon bei Temperaturen weit unter 100° vollständig. Bei hohem Zinkgehalt sind die Katalysatoren zur verlustlosen Dehydrierung von Naphthenen im Wasserstoffstrom vorzüglich geeignet. Da Paraffine nicht in nennenswertem Maße der destruktiven Hydrierung unterliegen, ist eine Dehydrierung von naphthenhaltigen Benzinfraktionen möglich.
Zur Kenntnis der Alkalizirkonate
Authors: Lehmann Hans‐Albert , Erzberger Peter 
Published: January 2005

AbstractAls einzige Verbindung im System Na2OZrO2 wird das Na2ZrO3 bestätigt. Im System K2OZrO2 existieren drei röntgenographisch unterscheidbare Formen des K2Zr2O5 (Form I K2O/ZrO2= 0,5:1;II<0,5:1;III>0,5:1). Die stabile aller drei Formen ist II. Die Hydrolyse des K2Zr2O5 führt in der Kälte nicht zu vollständiger Zersetzung, sondern ist beendet, wenn etwa ¼ des Gehaltes an Kalium gelöst ist. Beim Erhitzen derartiger Hydrolyseprodukte entsteht unter Freiwerden von ZrO2 die Form III. Die Hydrolyse wird als Ionenaustausch K+H+ gedeutet. Das System Rb2OZrO2 enthält ebenfalls nur eine einzige Verbindung, das Rb2Zr2O5, das wahrscheinlich mit K2ZrO2O5 I isotyp ist. An Zirkonat des Lithiums werden nachgewiesen Li4ZrO4, Li2ZrO3, und Li2Zr2O5. Das Dizirkonat entsteht beim Erhitzen von Methanolyseprodukten des Li4ZrO4. Dieses reagiert mit absolutem Methanol gemäß
Katalytische Untersuchungen an Legierungen. XXI. Über die Hydrierung des Acetons an pulverförmigen Nickel‐Legierungskatalysatoren
Authors: Kinza Horst , Rienäcker GÜNther 
Published: January 2005

AbstractVersuche zur experimentellen Überprüfung der d‐Lücken‐Theorie der Metallkatalysatoren zeigen, daß der Einfluß von Eisenzusätzen zu Nickel‐Katalysatoren durch geringe Kupfersätze aufgehoben werden kann. Kupferzusätze von 5% bewirken eine Änderung der katalytischen Aktivität um etwa eine Größenordnung.
Stress‐coping‐support in rural communities: A model for primary prevention
Authors: Kenkel Mary Beth 
Published: January 2005

ConclusionBecause of the relatively small and homogeneous population in rural communities, community‐wide prevention efforts are often more manageable than in urban areas. Community needs and resources can be identified more easily, and the feasibility of different interventions can be assessed more readily.To guide the rural prevention agent in developing community programs, the stress‐coping‐support framework has been proposed here. The value of this model is that it delineates the aspects of community life that must be assessed, and it outlines several different intervention goals. The model in its most general form proposes that prevention activities should reduce stress, increase coping, and build support. While this model can be applied to any community or target group, the framework has been elaborated here to address the unique physical, occupational, and societal characteristics of rural communities.Although some of the issues in applying this model to rural, as opposed to urban, areas have been pointed out here, the variation among rural communities has not been addressed fully. The different types of rural communities, e.g., the mining town, the isolated farmlands, the Indian reservation, have unique characteristics which may determine whether a proposed prevention program is needed, feasible, and effective.It is hoped that rural practitioners, long sensitive to the need for prevention, will use this model to devise additional prevention directions and to generate useful and culturally syntonic programs for their communities.
Southern Appalachia: Analytical models, social services, and native support systems
Authors: Keefe Susan Emley 
Published: January 2005

ConclusionsThe model of ethnicity has been applied in this paper to Appalachian natives. The problems suffered by Appalachians in terms of high dropout rates, institutional discrimination, prejudice, and stereotyping are familiar to other ethnic minority groups. Yet because the majority of the population in Appalachia are racially indistinct from mainstream Americans, there is resistance to the notion of ethnic difference. This has significant repercussions. Ironically, service providers and others in the region often recognize the distinctive nature of native Appalachians while, at the same time, reaffirming that they are white Americans like anywhere else. This is often said with good intentions. The result, however, justifies a lack of action taken to improve services for native Appalachians. If they are perceived as no different, inequalities go unrecognized and unredressed. If, on the other hand, differences are perceived only on the basis of socioeconomic class and/or rural residence, social services may miss the cultural dimension that may be all‐important in identifying problems and potential means of improvement. It is hoped that application of the notion of ethnicity to mountain people will be helpful in the structuring of human services in the region.
Surgical management of primary and secondary tumors in the pterygopalatine fossa
Authors: Jian Xin‐Chun , Wang Cheng‐Xing , Jiang Can‐Hua 
Published: January 2005

OBJECTIVEThis article describes a surgical approach that has been applied to managing primary tumors in the pterygopalatine fossa and secondary tumors involving the pterygopalatine fossa.PATIENTS AND METHODSThe Barbosa approach was modified by adding a lateral incision in the mandibular gingivobuccal fold from the canine tooth to the retromolar area. This technique was applied to nine patients with primary and secondary tumors in the pterygopalatine fossa. All patients had been observed by clinical examinations, MRI, and CT examinations.RESULTSThis technique allowed a large, inferiorly based flap to be raised, which includes the parotid gland. The masseter and temporalis muscles were divided horizontally, and the ascending ramus of the mandible was osteotomied between the mandibular angle and the sigmoid notch and reflected to expose the tumor in the pterygopalatine fossa and maxillary sinus. We have applied this technique in 9 patients. Of the 9 patients in our study, 5 (55%) were male and 4 (45%) were female. The median age of the patients at the time of operation for primary and secondary tumors in the pterygopalatine fossa was 49.5 years (range, 19–66 years). Four of the 9 patients had primary tumors in the pterygopalatine fossa. One patient had a tumor in the pterygoaplatine fossa extending into the maxillary sinus, 2 patients had tumors occurring in the maxilla involving the pterygopalatine fossa, 2 patients had tumors from the deep lobe of the parotid gland to the pterygopalatine fossa, and 1 patient had extracranial meningioma. Nine patients have been followed up from 3 months to 9 years and 6 months, and 1 patient had recurrence 2 years and 2 months postoperatively.CONCLUSIONThis technique is especially useful to tumors in the pterygopalatine fossa and tumors in the pterygopalatine fossa extending into the maxillary sinus.
Efficacy of topotecan treatment on antioxidant enzymes and TBA‐RS levels in submandibular glands of rabbits: An experimental study
Authors: Muluk Nuray Bayar , Kisa Üçler , Kaçmaz Murat , Apan Alpaslan , Koç CAN 
Published: January 2005

OBJECTIVEThe aim of this study was to investigate the effects of topotecan (Hycamtin), a topoisomerase I inhibiting anticancer agent, on antioxidant enzymes (SOD, CAT, and GSH‐Px) and TBA‐RS values of the submandibular glands of the rabbits.STUDY DESIGN AND SETTINGThe study was conveyed in two groups (Group I, II) and control with a total of 24 rabbits. Eight rabbits in group I received intravenous (i.v.) topotecan (0.25 mg/kg once daily) for 3 days. Eight rabbits in group II received i.v. topotecan (0.5 mg/kg once daily) for 3 days. On the 15th day after administration of topotecan, sub‐mandibular glands were removed and levels of the SOD, CAT, and GSH‐Px and the TBA‐RS in the sub‐mandibular glands of the rabbits were examined.RESULTSSOD, CAT, and GSH‐Px values were significantly higher in high‐dose topotecan group compared to control group (P < 0.05). SOD and TBA‐RS values were significantly higher in high‐dose topotecan group compared to low‐dose topotecan group (P < 0.05).CONCLUSIONIt was concluded that, to prevent the hazardous effects of oxygen free radicals due to topotecan, antioxidant enzymes SOD, CAT, and GSH‐Px were increased. The higher levels of the TBA‐RS values in group II showed that permanent damage was present because of high‐dose topotecan administration in the submandibular glands of the rabbits.
New Interpretations of the Spanish Civil War
Authors: NÚÑEZ XOSÉ-MANOEL 
Published: January 2005

Michel Lefebvre and Rémi Skoutelsky, Les Brigades Internationales. Images retrouvées (Paris: Editions du Seuil, 2003), 192 pp., €45.00 (hb), ISBN 2-02-052390-6.Helen Graham, The Spanish Republic at War, 1936–1939 (Cambridge: Cambridge University Press, 2003), 472 pp., £13.99 (pb), ISBN 0-521-45932-X.Javier Rodrigo, Los campos de concentración franquistas. Entre la historia y la memoria (Madrid: Siete Mares, 2003), 251 pp., €18.00 (pb), ISBN 84-933012-05.Michael Seidman, A ras de suelo. Historia social de la República durante la Guerra Civil (Madrid: Alianza, 2003), 388 pp., €18.70 (pb), ISBN 84-206-3706-8 (English edition: Republic of Egos. A Social History of the Spanish Civil War (Madison, WI: University of Wisconsin Press, 2002), 304 pp., $24.95 (pb), ISBN 0299178641).The Spanish Civil War is among the most passionate conflicts of the long twentieth century, as one which arouses considerable emotion, in favour of either the Republican or the Francoist side. Its duration – far beyond what had been predicted in July 1936 by the military rebels and most international observers – together with its rapid conversion into an arena of international dispute between two opposing world-views, ‘fascism’ and ‘anti-fascism’, made it of long-standing interest for world public opinion. Moreover, its internationalisation made it appear as the prelude to the Second World War. The survival of the Francoist dictatorship until 1975 contributed to the fact that the first historical analyses of the Spanish Civil War had to be written abroad and by foreign scholars, mostly French and Anglophone. Even now the Spanish conflict continues to be a matter of interest for non-Spanish scholars, who rely on a long-standing tradition of scholarship on the topic.
Evolutionarily Divergent Extradiol Dioxygenases Possess Higher Specificities for Polychlorinated Biphenyl Metabolites
Authors: Fortin Pascal D. , Lo Andy T.-F. , Haro María-Amparo , Kaschabek Stefan R. , Reineke Walter , Eltis Lindsay D. 
Published: January 2005

ABSTRACT

The reactivities of four evolutionarily divergent extradiol dioxygenases towards mono-, di-, and trichlorinated (triCl) 2,3-dihydroxybiphenyls (DHBs) were investigated: 2,3-dihydroxybiphenyl dioxygenase (EC 1.13.11.39) from
Burkholderia
sp. strain LB400 (DHBD
LB400
), DHBD
P6
-I and DHBD
P6
-III from
Rhodococcus globerulus
P6, and 2,2′,3-trihydroxybiphenyl dioxygenase from
Sphingomonas
sp. strain RW1 (THBD
RW1
). The specificity of each isozyme for particular DHBs differed by up to 3 orders of magnitude. Interestingly, the
K
m
app
values of each isozyme for the tested polychlorinated DHBs were invariably lower than those of monochlorinated DHBs. Moreover, each enzyme cleaved at least one of the tested chlorinated (Cl) DHBs better than it cleaved DHB (e.g., apparent specificity constants for 3′,5′-dichlorinated [diCl] DHB were 2 to 13.4 times higher than for DHB). These results are consistent with structural data and modeling studies which indicate that the substrate-binding pocket of the DHBDs is hydrophobic and can accommodate the Cl DHBs, particularly in the distal portion of the pocket. Although the activity of DHBD
P6
-III was generally lower than that of the other three enzymes, six of eight tested Cl DHBs were better substrates for DHBD
P6
-III than was DHB. Indeed, DHBD
P6
-III had the highest apparent specificity for 4,3′,5′-triCl DHB and cleaved this compound better than two of the other enzymes. Of the four enzymes, THBD
RW1
had the highest specificity for 2′-Cl DHB and was at least five times more resistant to inactivation by 2′-Cl DHB, consistent with the similarity between the latter and 2,2′,3-trihydroxybiphenyl. Nonetheless, THBD
RW1
had the lowest specificity for 2′,6′-diCl DHB and, like the other enzymes, was unable to cleave this critical PCB metabolite (
k
cat
app
< 0.001 s
−1
).
Analysis of a DtxR-Regulated Iron Transport and Siderophore Biosynthesis Gene Cluster in
Corynebacterium diphtheriae
Authors: Kunkle Carey A. , Schmitt Michael P. 
Published: January 2005

ABSTRACT

This report describes a genetic locus associated with siderophore biosynthesis and transport in
Corynebacterium diphtheriae
. A BLAST search of the
C. diphtheriae
genome identified a seven-gene cluster that included four genes, designated
ciuA, ciuB, ciuC
, and
ciuD
, whose predicted products are related to ABC-type iron transporters. Downstream from
ciuD
is the
ciuE
gene, whose predicted product is similar to the aerobactin biosynthetic enzymes IucA and IucC. The CiuE protein, which has a predicted mass of 121,582 Da and is approximately twice the size of either IucC or IucA, is homologous to each of these proteins in both its N- and C-terminal regions.
C. diphtheriae ciuE
deletion mutants exhibited a defect in siderophore production, iron uptake, and growth in low-iron medium. Mutations in the
ciuA
gene, whose predicted product is a lipoprotein component of an iron transport system, resulted in a severe defect in iron uptake and reduced ability to use the
C. diphtheriae
siderophore as an iron source. Site-directed mutations in
irp6A
, a gene previously reported to be associated with siderophore transport, had no effect on iron uptake or the utilization of the
C. diphtheriae
siderophore as an iron source. Transcriptional analysis demonstrated that expression of
ciuA
and
ciuE
is DtxR and iron regulated, and DNase I protection experiments confirmed the presence of DtxR binding sites upstream from each of these genes. Thus, this iron- and DtxR-regulated gene cluster is involved in the synthesis and transport of the
C. diphtheriae
siderophore.
Identification ofChlamydia trachomatisGenomic Sequences Recognized by Chlamydial Divalent Cation-Dependent Regulator A (DcrA)
Authors: Rau Annette , Wyllie Susan , Whittimore Judy , Raulston Jane E. 
Published: January 2005

ABSTRACTTheChlamydia trachomatisdivalent cation-dependent regulator (DcrA), encoded by open reading frame CT296, is a distant relative of the ferric uptake regulator (Fur) family of iron-responsive regulators. Chlamydial DcrA specifically binds to a consensusEscherichia coliFur box and is able to complement anE. coliFur mutant. In this report, theE. coliFur titration assay (FURTA) was used to locate chlamydial genomic sequences that are recognized byE. coliFur. The predictive regulatory regions of 28C. trachomatisopen reading frames contained sequences functionally recognized byE. coliFur; targets include components of the type III secretion pathway, elements involved in envelope and cell wall biogenesis, predicted transport proteins, oxidative defense enzymes, and components of metabolic pathways. Selected FURTA-positive sequences were subsequently examined for recognition byC. trachomatisDcrA using an electrophoretic mobility shift assay. The resultant data show thatC. trachomatisDcrA binds to native chlamydial genomic sequences and, overall, substantiate a functional relationship between chlamydial DcrA and the Fur family of regulators.