bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaktion von Carbonsäuren mit Tetraphospha‐chalkogenadiiodiden in CS2‐Lösungen
Authors: Blachnik Roger , Neto António 
Published: January 2005

AbstractDie Reaktion von α‐P4E3I2 (E = S und/oder Se) mit Carbonsäuren, HR, deren pKs‐Werte größer als 3 sind, ergab in Gegenwart von Triethylamin α‐P4E3(I)R und α‐P4E3R2, die in den Reaktionslösungen durch 31P–NMR‐Spektroskopie nachgewiesen wurden. Bei pKs‐Werten <3 führte nur die Umsetzung mit Trimethylzinncarboxyverbindungen zu entsprechenden Produkten in vergleichbaren Ausbeuten.Die chemischen Verschiebungen der ligandentragenden Phosphoratome von α‐P4E3R2 hängen primär von der Elektronegativität des Sauerstoffs ab, sekundär vom induktiven Effekt des organischen Restes der Carboxylsäure. Die chemischen Verschiebungen und Kopplungskonstanten von α‐P4E3(I)R können aus den Daten der symmetrischen Verbindungen α‐P4E3I2 und α‐P4E3R2 abgeschätzt werden, dabei deuten leichte Abweichungen in den Brüchen‐ und Seitenkopplungskonstanten auf eine Verdrillung des Molekülgerüstes durch die unterschiedlich großen Liganden. Die endocyclische Substitution von Schwefel durch Selen in α‐P4S3R2 ergab im Vergleich zu α‐P4SnSe3−nI2 signifikante Unterschiede im Verhalten der Seitenkopplungskonstanten, was auf eine sterische Wechselwirkung der Carboxylgruppe mit dem Gerüst deutet.
Zur Chemie des Galliums. 10. N‐Trimethylsilyl‐substituierte Aminogallane
Authors: Linti Gerald , Frey Ronald 
Published: January 2005

AbstractDie Darstellung der monomeren Mono(amino)gallane 9, 10 gelingt durch Umsetzung von Dialkylgalliumchloriden R2GaCl (R = Me, Et) mit den Lithiumamiden LiN(SiMe3)R′ [R′ = tBu, 2,6‐iPr2C6H3 ( = dipp)]. Aus Gallium(III)chlorid und LiN(SiMe3)dipp entsteht das Bis(amino)galliumchlorid dipp(SiMe3)NGa(Cl)Ndipp(SiMe2)N(SiMe3)dipp 12. Die Oxidation von 9 ergibt das Aminoethoxygallan [dipp(SiMe3)NGa(Et)μ‐OEt]2 13, dessen Struktur mit der des Alkoxygallans 14 verglichen wird.
Synthesis and Structure of Ba6Mg7F26
Authors: Kubel F. , Hagemann H. , Bill H. 
Published: January 2005

AbstractA new compound in the binary phase diagram of BaF2 and MgF2 was synthesized. After Czrochalsky growth of BaMgF4, needle shaped crystals were found on the surface of the cooled residual mass. The compound Ba6Mg7F26 crystallizes in the orthorhombic space group Immm with lattice parameters of a = 585.35(4), b = 1214.95(7), and c = 1511.09(9) pm.The global structure can be described as build up of perovskite like blocks and rutile related parts. Magnesium ions have an octahedral fluoride environment with minimum (maximum) bond distances of 192.1(2) (227.4(3)) pm.Two different barium environments with coordination number (C.N.) of 12 + 1 (Ba1) and 12 (Ba2) were found. The different fluoride ions can have C.N. of 6, 4 or 3 with the nearest metal atoms.Preliminary Raman spectra show significant differences between BaMgF4 and Ba6Mg7F26.
Life events and depression: The plot thickens
Authors: Hammen Constance 
Published: January 2005

ConclusionsAlthough we certainly agree with Beck's original ideas that depression results from people's negative interpretations of events, unlike Beck we believe that many of the interpretations are not necessarily distortions. Awful and difficult events happen to many people, and many depressions are preceded by truly negative life stressors. We propose that stressors result both from fate and from human agency. And maybe we will get as much mileage from studies of individual differences in stress generation and stress resolution as from a previous round of studies of individual differences in cognitions about stress. How do people create and manage their environments? Just as the study of depression has profited enormously from exploring its antecedent social context, we propose that even stressful events need to be studied in context—especially the interpersonal and family context. These processes shift over time and have mutual influences on each other. This leads to some very complex multigenerational, historical, transactional, and cognitive models, and that is what I meant when I titled this work “the plot thickens.”
Cluster analysis in community research: Epistemology and practice
Authors: Rapkin Bruce D. , Luke Douglas A. 
Published: January 2005

AbstractCluster analysis refers to a family of methods for identifying cases with distinctive characteristics in heterogeneous samples and combining them into homogeneous groups. This approach provides a great deal of information about the types of cases and the distributions of variables in a sample. This paper considers cluster analysis as a quantitative complement to the traditional linear statistics that often characterize community psychology research. Cluster analysis emphasizes diversity rather than central tendency. This makes it a valuable tool for a wide range of familiar problems in community research. A number of these applications are considered here, including the assessment of change over time, network composition, network density, person‐setting relationships, and community diversity. A User's Guide section is included, which outlines the major decisions involved in a basic cluster analyses. Despite difficulties associated with the identification of optimal cluster solutions, carefully planned, theoretically informed application of cluster analysis has much to offer community researchers.
Lesbian, gay, and bisexual youth in community settings: Personal challenges and mental health problems
Authors: D'Augelli Anthony R. , Hershberger Scott L. 
Published: January 2005

AbstractStudied 194 lesbian, gay, and bisexual youth aged 21 and younger who attended programs in 14 community centers to determine the personal challenges they face due to their sexual orientation and their responses to these stresses. First awareness of sexual orientation typically occurred at age 10, but disclosure to another person did not occur until about age 16. There was much variability in sexual behavior, and many youths reported both same‐sex and opposite‐sex sexual experiences. Although most had told at least one family member about their sexual orientation, there remained much concern about family reactions. Suicide attempts were acknowledged by 42% of the sample. Attempters significantly differed from nonattempters on several milestones of sexual orientation development, social aspects of sexual orientation, parents' knowledge of sexual orientation, and mental health problems.
Probing the effects of individual components in multiple component prevention programs
Authors: West Stephen G. , Aiken Leona S. , Todd Michael 
Published: January 2005

AbstractAssessing the contributions of individual components in multi‐component interventions poses complex challenges for prevention researchers. We review the strengths and weaknesses of designs and analyses that may be useful in answering three questions: (1) Is each of the individual components contributing to the outcome? (2) Is the program optimal? and (3), Through what processes are the components of the program achieving their effects? Factorial and fractional factorial designs in which a systematically selected portion of all possible treatment combinations is implemented are used to address question 1. Response surface designs in which each component is quantitatively scaled are explored in relation to question 2. Mediational analysis, a hybrid of experimental and correlational approaches, is considered in relation to question 3. Design enhancements are offered that may further strengthen some of these techniques. These techniques offer promise of enhancing both the basic science and applied science contributions of prevention research.
Primary prevention of secondary disorders: A proposal and agenda
Authors: Kessler Ronald C. , Price Richard H. 
Published: January 2005

AbstractThis paper calls for consideration of a new class of preventive interventions designed explicitly to prevent comorbidity of psychiatric disorders. Epidemiologic data show that successful interventions of this type could be extremely valuable, as up to half of lifetime psychiatric disorders and an even larger percent of chronic and seriously impairing disorders occur to people with a prior history of some other disorder. Furthermore, a review of etiologic hypotheses concerning the causes of comorbidity suggests that interventions aimed at primary prevention of secondary disorders might be feasible. However, more basic risk factor research is needed on the causes of comorbidity before we can make a clear assessment of feasibility and discover promising intervention targets. A number of methodological problems arise in carrying out this type of formative research. These problems are reviewed and suggestions are offered for solutions involving innovations in measurement, design, and data analysis.
Linking qualitative and quantitative methods in cross‐cultural survey research: Techniques from cognitive science
Authors: Hines Alice M. 
Published: January 2005

AbstractSurvey research with diverse cultural and ethnic minority groups is a complex and challenging endeavor that confronts the researcher with problems related to linguistic and conceptual equivalence and measurement as well as problems related to difficulties that respondents have with the sociocultural dimensions of the survey/interview process. One way to improve the quality of cross‐cultural surveys and to insure that the findings are culturally relevant and accurate is to combine qualitative and quantitative methods. This paper proposes that certain qualitative techniques from cognitive science, specifically cognitive anthropology and cognitive psychology, are particularly well suited to being combined with survey research. These techniques provide information corresponding to the underlying thought processes of respondents and enable researchers to better understand how different cultural and ethnic groups construe the world. The information obtained can be used improve the formulation of survey questions, design and structure questionnaire formats to coincide with the way particular groups organize concepts, and help researchers understand difficulties respondents may have with the survey/interview process. In addition, the techniques produce data that are easily codifiable and more manageable than traditional qualitative techniques including participant observation and in‐depth interviews.
Using focus groups to facilitate culturally anchored research
Authors: Hughes Diane , DuMont Kimberly 
Published: January 2005

AbstractScholars have acknowledged the need to anchor scientific knowledge about social and psychological processes in the norms, values, and experiences of the partticular population under study. This article describes how focus groups can be incorporated into the planning stages of a research pogram to facilitate these goals. After a brief overview of teh central components of focus group research, and example from a program of research involving dual‐earner African American families is used to as an illustration. The article describes how (a) the identification of cultural knowledge and (b)access to the language participants use to think and talk about a topic can help researchers formulate a conceptual framework, identify important constructs, and develop appropriate instruments for assessing constructs. Some strengths and limitations of focus group research are discussed.
Psychological aspects of genetic counseling. VII. Thoughts on directiveness
Authors: Kessler Seymour 
Published: January 2005

AbstractDirectiveness and nondirectiveness in genetic counseling are poorly understood on the operational level, and information about what counselors allege they do and what actually is done in practice is lacking. Although they are often thought of as diametrically opposite approaches, when viewed as strategies of persuasion, their similarities become more apparent. Directive counselors attempt to influence the counselee's behavior, whereas nondirective ones attempt to influence the latter's thinking processes; there is need for both approaches. Directiveness may also sometimes occur because of inadequate interview skills. The case made for directiveness is discussed and critiqued, available research is reviewed, and suggestions for future studies are advanced.
Arachidonic acid inhibits the store-operated Ca2+ current in rat liver cells
Authors: RYCHKOV Grigori Y. , LITJENS Tom , ROBERTS Michael L. , BARRITT Greg J. 
Published: January 2005

Vasopressin and other phospholipase-C-coupled hormones induce oscillations (waves) of [Ca2+]cyt (cytoplasmic Ca2+ concentration) in liver cells. Maintenance of these oscillations requires replenishment of Ca2+ in intracellular stores through Ca2+ inflow across the plasma membrane. While this may be achieved by SOCs (store-operated Ca2+ channels), some studies in other cell types indicate that it is dependent on AA (arachidonic acid)-activated Ca2+ channels. We studied the effects of AA on membrane conductance of rat liver cells using whole-cell patch clamping. We found no evidence that concentrations of AA in the physiological range could activate Ca2+-permeable channels in either H4IIE liver cells or rat hepatocytes. However, AA (1–10 μM) did inhibit (IC50=2.4±0.1 μM) Ca2+ inflow through SOCs (ISOC) initiated by intracellular application of Ins(1,4,5)P3 in H4IIE cells. Pre-incubation with AA did not inhibit ISOC development, but decreased maximal amplitude of the current. Iso-tetrandrine, widely used to inhibit receptor-activation of phospholipase A2, and therefore AA release, inhibited ISOC directly in H4IIE cells. It is concluded that (i) in rat liver cells, AA does not activate an AA-regulated Ca2+-permeable channel, but does inhibit SOCs, and (ii) iso-tetrandrine and tetrandrine are effective blockers of CRAC (Ca2+-release-activated Ca2+) channel-like SOCs. These results indicate that AA-activated Ca2+-permeable channels do not contribute to hormone-induced increases or oscillations in [Ca2+]cyt in liver cells. However, AA may be a physiological modulator of Ca2+ inflow in these cells.
The Reactions of Deuterium Atoms with Methane and Ethane
Authors: Steacie E. W. R. , Phillips N. W. F. 
Published: January 2005

The reactions of deuterium atoms with methane and ethane have been investigated, the atoms being produced by the discharge tube method and by photosensitization with mercury. The activation energies found were 11.7 Kcal. for methane, and 6.3 Kcal. for ethane.
The mechanism of the latter reaction is discussed, and it is concluded that the measured activation energy is that of the reactionD+C2H6=C2H5+HD.Hence the reactionH+C2H6=C2H5+H2must have approximately the same energy of activation. On this assumption the free radical chain theory of first order reactions is discussed in the light of the recent work of Patat and Sachsse.
Intensities of Electronic Transitions in Molecular Spectra II. Charge-Transfer Spectra
Authors: Mulliken Robert S. 
Published: January 2005

Two related types of high intensity molecular spectra are discussed. These are designated as charge-resonance spectra and charge-transfer spectra. In the molecular orbital approximation, both these types usually involve transfer of one electron from a bonding to the corresponding antibonding molecular orbital. In the atomic orbital approximation, charge-resonance spectra involve a transition from a symmetrical to a corresponding antisymmetrical state, the wave function of each of these two states being a linear combination of two wave functions representing two hypothetical states of a molecule that are equivalent or nearly so but different in charge distribution. Charge-transfer spectra in the atomic orbital approximation involve a transition from a state having a non-ionic to one having an ionic wave function (N→V transition). Theoretical equations for dipole strengths and f values for both these types are given, in each case calculated according to each of the two approximations. The equations are very simple, the dipole strength being proportional to the distance across which the charge resonates or is transferred.
Examples of charge-resonance spectra in H2+, O2+, and NO are cited, and N→V (charge-transfer) transitions in the spectra of the molecules H2, O2, C2H4, C6H6, and the halogens are discussed. Although experimental data are scanty, they appear to be in harmony with the theory. For the O2 Schumann-Runge bands, where f is accurately known experimentally, its value is intermediate between the values calculated theoretically according to the two approximations. A suggestion is made to explain Carr and Stücklen's result of progressive broadening toward longer wave-lengths in the N→V spectrum as radicals are substituted for H atoms in C2H4. The 1A1g→1E1u transition in C6H6 calculated by Sklar and identified by him with bands near and below λ2000 is here concluded to be of the N→V class. In connection with the theory of light absorption in organic compounds, it will be shown in later papers that intense transitions in the visible and ordinary ultraviolet probably can be accounted for in a large proportion of cases (including dyes) as charge-transfer (N→V) spectra, or, in part, as charge-resonance spectra. The existence of spectra of the charge-resonance type in certain kinds of dyes has already been recognized and very briefly discussed by Pauling in the new edition of Gilman's Organic Chemistry.
The Centrifugal Distortion of Axial Molecules
Authors: Slawsky Z. I. , Dennison David M. 
Published: January 2005

The theory of the semi-rigid rotator developed by Wilson and Howard has been applied to the axial molecules YX3 and ZYX3. It is found that the change in rotational energy, δW, caused by the centrifugal distortion, can be expressed in terms of the quantum numbers J and K and as a function of the potential constants and the molecular dimensions. The formula is evaluated explicitly for NH3, and ND3, and for the former is, in cm—1: δWJKhC=−0.000625J2(J+1)2+0.000950K2J(J+1) +0.000799J(J+1)−0.000630K4−0.00189K2.The pure rotation lines of NH3 and of ND3 are calculated and compared with the observations of Wright and Randall, and of Barnes. The agreement is very satisfactory. The theory predicts that the rotation lines are multiple. The spacing of this fine structure was too small to be observable in the region mapped by Wright and Randall but should be possible to detect in the case of the higher members of the rotation series.
We have also calculated the pure rotation spectrum of PH3 by using Howard's approximate values of the dimensions and force constants of this molecule. The agreement with experimental values is as good as could be expected from such rough data.
The crystal structures of semi‐synthetic aequorins
Authors: Toma Sachiko , Chong Khoon Tee , Nakagawa Atsushi , Teranishi Katsunori , Inouye Satoshi , Shimomura Osamu 
Published: January 2005

AbstractThe photoprotein aequorin emits light by an intramolecular reaction in the presence of a trace amount of Ca2+. Semi‐synthetic aequorins, produced by replacing the coelenterazine moiety in aequorin with the analogues of coelenterazine, show widely different sensitivities to Ca2+. To understand the structural basis of the Ca2+‐sensitivity, we determined the crystal structures of four semi‐synthetic aequorins (cp‐, i‐, br‐ and n‐aequorins) at resolutions of 1.6–1.8 Å. In general, the protein structures of these semi‐synthetic aequorins are almost identical to native aequorin. Of the four EF‐hand domains in the molecule, EF‐hand II does not bind Ca2+, and the loop of EF‐hand IV is clearly deformed. It is most likely that the binding of Ca2+ with EF‐hands I and III triggers luminescence. Although little difference was found in the overall structures of aequorins investigated, some significant differences were found in the interactions between the substituents of coelenterazine moiety and the amino acid residues in the binding pocket. The coelenterazine moieties in i‐, br‐, and n‐aequorins have bulky 2‐substitutions, which can interfere with the conformational changes of protein structure that follow the binding of Ca2+ to aequorin. In cp‐aequorin, the cyclopentylmethyl group that substitutes for the original 8‐benzyl group does not interact hydrophobically with the protein part, giving the coelenterazine moiety more conformational freedom to promote the light‐emitting reaction. The differences of various semi‐synthetic aequorins in Ca2+‐sensitivity and reaction rate are explained by the capability of the involved groups and structures to undergo conformational changes in response to the Ca2+‐binding.
Sequence swapping does not result in conformation swapping for the β4/β5 and β8/β9 β‐hairpin turns in human acidic fibroblast growth factor
Authors: Kim Jaewon , Lee Jihun , Brych Stephen R. , Logan Timothy M. , Blaber Michael 
Published: January 2005

AbstractThe β‐turn is the most common type of nonrepetitive structure in globular proteins, comprising ∼25% of all residues; however, a detailed understanding of effects of specific residues upon β‐turn stability and conformation is lacking. Human acidic fibroblast growth factor (FGF‐1) is a member of the β‐trefoil superfold and contains a total of five β‐hairpin structures (antiparallel β‐sheets connected by a reverse turn). β‐Turns related by the characteristic threefold structural symmetry of this superfold exhibit different primary structures, and in some cases, different secondary structures. As such, they represent a useful system with which to study the role that turn sequences play in determining structure, stability, and folding of the protein. Two turns related by the threefold structural symmetry, the β4/β5 and β8/β9 turns, were subjected to both sequence‐swapping and poly‐glycine substitution mutations, and the effects upon stability, folding, and structure were investigated. In the wild‐type protein these turns are of identical length, but exhibit different conformations. These conformations were observed to be retained during sequence‐swapping and glycine substitution mutagenesis. The results indicate that the β‐turn structure at these positions is not determined by the turn sequence. Structural analysis suggests that residues flanking the turn are a primary structural determinant of the conformation within the turn.
EDD, a novel phosphotransferase domain common to mannose transporter EIIA, dihydroxyacetone kinase, and DegV
Authors: Kinch Lisa N. , Cheek Sara , Grishin Nick V. 
Published: January 2005

AbstractUsing a recently developed program (SCOPmap) designed to automatically assign new protein structures to existing evolutionary‐based classification schemes, we identify a evolutionarily conserved domain (EDD) common to three different folds: mannose transporter EIIA domain (EIIA‐man), dihydroxyacetone kinase (Dak), and DegV. Several lines of evidence support unification of these three folds into a single superfamily: statistically significant sequence similarity detected by PSI‐BLAST; “closed structural grouping” using DALI Z‐scores (each protein inside a group finds all other group members with scores higher than those to proteins outside the group) that includes only these proteins sharing a unique α‐helical hairpin at the C‐terminus and excludes all other proteins with similar topology; similar domain fusions connect Dak and DegV, and genomic neighborhood organizations connect Dak and EIIA‐man. Finally, both Dak and EIIA‐man perform similar phosphotransfer reactions, suggesting a phosphotransferase activity for the DegV‐like family of proteins, whose function other than lipid binding revealed in the crystal structure remains unknown.