bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kulturen des Experiments
Authors: Rheinberger Hans‐Jörg 
Published: May 2007

AbstractCultures of Experiment. – It is generally accepted that the development of modern science is rooted in experiment. Yet for a long time, experimentation did not occupy a prominent role in history of science. With the practical turn in science studies, this has begun to change. This paper is concerned with cultures of experiment. In the first part, a suggestion is made as to how the concept of experimental culture can be used to go beyond a history of disciplines. In the second part, a particular experimental culture in the life sciences is looked at more closely. A survey is given on the changing forms of in vitro experimentation, that is, on analyzing biological functions in a test tube.
An Activity, Stability and Selectivity Comparison of Propioin Synthesis by Thiamine Diphosphate‐Dependent Enzymes in a Solid/Gas Bioreactor
Authors: Mikolajek Renaud , Spiess Antje C. , Pohl Martina , Lamare Sylvain , Büchs Jochen 
Published: May 2007

AbstractEnzymatic carboligation in a solid/gas bioreactor represents a new challenge in biotechnology. In this paper, the continuous gas‐phase production of propioin from two propanal molecules by using thiamine diphosphate‐dependent enzymes was studied. Two enzymes were used, namely benzaldehyde lyase (BAL) from Pseudomonas fluorescens and benzoylformate decarboxylase (BFD) from Pseudomonas putida. The enzymes are homologous and catalyze carboligase and carbolyase reactions in which no external cofactor regeneration is needed. The influence of water and substrate activity on the initial reaction rate and biocatalyst stability was investigated. An increase in water activity raised the initial reaction rates to the maximal values of 250 and 80 U g−1 for BAL and BFD, respectively. The half‐life showed the same trend with maximal values of 50 and 78 min for BAL and BFD, respectively. The increase in the half‐life by increasing water activity was unexpected. It was also observed that BFD is more stable than BAL in the presence of the substrate propanal. Both enzymes showed substrate inhibition in the kinetic studies, and BAL was also deactivated during the reaction. Unexpectedly, the stereoselectivity of both enzymes (ee of 19 % for BAL and racemic mixture for BFD) was significantly impaired in the gas phase compared to the liquid phase.
Gold‐Catalyzed Cyanosilylation Reaction: Homogeneous and Heterogeneous Pathways
Authors: Cho Woo Kyung , Lee Jungkyu K. , Kang Sung Min , Chi Young Shik , Lee Hee‐Seung , Choi Insung S. 
Published: May 2007

AbstractGold had been considered to be an extremely inert metal, but recently it was found that nanometer‐sized gold particles on metal‐oxide supports acted as catalysts for simple organic reactions, such as oxidation and hydrogenation, even at or below room temperature. Herein, we report that gold nanoparticles (AuNPs) of zero oxidation state (Au0) are catalytically active for a CC bond‐forming reaction, the cyanosilylation of aldehydes. The AuNP‐catalyzed cyanosilylation proceeded smoothly at room temperature with 0.2 wt % loading of AuNPs. The reactions of aromatic aldehydes were almost quantitative, except for benzaldehyde derivatives containing the electron‐withdrawing NO2 group, and α,β‐unsaturated aromatic aldehydes were the most reactive substrates. The reactions also went smoothly for aliphatic aldehydes. Mechanistic studies indicated that the reactions proceeded both homogeneously and heterogeneously: homogeneous catalysis by leached gold species and heterogeneous catalysis by the adsorption of the reactants (aldehydes and trimethylsilyl cyanide) onto AuNPs. The ratio of homogeneous and heterogeneous catalysis was estimated to be ≈4:1.
Chemical Anisotropies of Carbon Nanotubes and Fullerenes Caused by the Curvature Directivity
Authors: Li Junqian , Jia Guixiao , Zhang Yongfan 
Published: May 2007

AbstractThe directional‐curvature theory is developed as a rational basis for the strain energy and the chemical reactivity in single‐walled carbon nanotubes (SWCNTs) and fullerenes. The directional curvature KD and its mean KM, derived from this theory, cover the overall curvatures of their bonds and atoms and break through the limitations of the pyramidalized‐angle θp approach, which is only available to atomic curvature. The directional‐curvature theory demonstrates that KD and KM depend directly on the strain or reactive binding energies of the bonds and atoms and that there is approximate curvature conservation in SWCNTs and fullerenes. Application of this theory to addition reactions of various SWCNTs and fullerenes shows that the slope of the straight line between the strain or binding energies and KD is close to a constant, which helps clarify the puzzle as to why some functionalizations of C70 occur at the relatively flat midsection.
Fabrication, Characterization, and Surface‐Enhanced Raman Activity Study of Silver Coated Gold Nanoparticulate Films
Authors: Fang Jing‐Huai , Zhong Chong‐Gui , Mu Ren‐Wang , Shi Jian‐Zhen , Ge Cun‐Wang 
Published: May 2007

AbstractThis paper reports a study on the preparation of Ag‐clad Au colloidal monolayer films by a combination of colloid self‐assembly and liquid phase microwave high‐pressure technique. Firstly, monodisperse Au nanoparticles prepared by microwave heating method were assembled onto a quartz slide. Then, these Au colloidal particles on the quartz surface acted as seeds for growing the Ag‐clad Au composite particulate films. The obtained particulate films were characterized by UV‐Vis spectra and atomic force microscopy. It was found that the thickness of the shell and thus the size of particles in the composite colloidal films could be controlled by deposition of Ag on the preformed Au colloidal particle film in the microwave reaction system, and such films significantly increased the surface‐enhanced Raman scattering enhancement (SERS) ability compared with Au colloidal particle films. Their strong enhancement ability may mainly stem from relatively large particle consisting of Ag cladding as well as effective coupling among particles in the Ag‐clad Au particle films.
Unusual Cycloadducts from the Dipolar Cycloaddition of Allenyl Perfluoroalkyl Sulfones to Nitrones
Authors: Wang Xiao‐Jin , Liu Jin‐Tao 
Published: May 2007

AbstractThe dipolar cycloaddition reaction of allenyl perfluoroalkyl sulfones (1) to nitrones (2) was described. Unlike nonfluorine‐containing allenyl sulfones, 1 reacted readily with 2 in ether at room temperature and unusual zwitterionic cycloadducts (3) were obtained in good yields due to the strong electron‐withdrawing effect of perfluoroalkyl groups. The structure of 3 was characterized by spectral analyses and X‐ray crystallography.
A Convenient and Environmentally Benign Method of Reducing Aryl Ketones or Aldehydes by Zinc Powder in an Aqueous Alkaline Solution
Authors: Zhang Chao‐Zhi , Yang Hui , Wu De‐Lin , Lu Guo‐Yuan 
Published: May 2007

AbstractA convenient and environmentally benign method for reducing the carbonyl group in hydroxy‐ and amino‐ 9,10‐anthracenediones, ortho (or para) acyl phenols and acyl anilines to a methylene group by zinc powder in an aqueous sodium hydroxide solution was reported. Based on theoretical calculations using the density functional theory (DFT), the mechanism of these reduction reactions was postulated. This mechanism can be applied to help predicting the reduced products of aryl ketones (or aldehydes) in an alkaline solution.
Synthesis and Characterization of New Material‐‐La/Zr/MMT Employed in Acetone Oxidation
Authors: Fan Li‐Ping , Chen Min , Zhang Yi‐Gai , Zhou Ren‐Xian , Zheng Xiao‐Ming 
Published: May 2007

AbstractA new material of zirconium pillared montmorillonite added with lanthanum (denoted as La/Zr/MMT) was prepared for acetone oxidation. Surface properties of the catalysts were investigated by means of XRD, TEM, TG‐DTA and BET methods. The XRD result indicated that the interlayer space of the montmorillonite was enlarged from 1.57 to 4.85 nm after the treatment with zirconium pillaring and the addition of lanthanum. N2 adsorption‐desorption result showed that by the process of zirconium pillaring, the specific surface area of the sample was increased to 128.0 m2/g, which was two times almost as large as pure montmorillonite. Simultaneously, the thermal stability was also enhanced. The activity of the new material on the total oxidation of acetone was investigated, and the results indicated that the catalytic activity of the montmorillonite was greatly improved. Over the sample of La/Zr/MMT, the T98 of acetone was obtained at 350 °C, while it needs 400 °C over the pure montmorillonite. After 0.1% Pd was supported on the sample of La/Zr/MMT, the T98 decreased from 350 to 280 °C, indicating the montmorillonite is a promising material for the control of some types of the volatile organic compounds such as acetone.
Two New C‐21 Steroidal Glycosides from the Stems of Stephanotis mucronata
Authors: Li Xiao‐Yu , Chen Feng‐Yang , Ye Yi‐Ping , Pan Yuan‐Jiang 
Published: May 2007

AbstractTwo new C‐21 steroidal glycosides, mucronatosides M(1) and N(2), were isolated from the stems of Stephanotis mucronata, together with one known compound stephanoside M(3). On the basis of chemical evidence and extensive spectroscopic methods, including one‐dimensional and two‐dimensional NMR, the structures of the two new compounds were identified as 12‐O‐tigloyl‐20‐O‐N‐methylanthraniloyl sarcostin 3‐O‐β‐D‐glucopyranosyl‐(1→4)‐6‐deoxy‐3‐O‐methyl‐β‐D‐allopyranosyl‐(1→4)‐(‐D‐cymaropyranosyl‐(1→4)‐β‐D‐cymaropyranoside (1), and 12‐O‐ cinnamoyl‐20‐O‐nicotinoyl(20S)‐pregn‐6‐ene‐3(,5(,8β,12β,14(,17β,20‐heptanol 3‐O‐β‐D‐glucopyranosyl‐(1→4)‐6‐deoxy‐3‐O‐methyl‐β‐D‐allopyranosyl‐(1→4)‐β‐D‐cymaropyranosyl‐(1→4)‐(‐D‐cymaropyranoside (2).
Secretory activity in medullary thyroid carcinoma: A cytomorphological and immunocytochemical study
Authors: Das Dilip K. , Mallik Mrinmay K. , George Sara S. , Sheikh Zaffar A. , Pathan Shahed K. , Haji Bahiyah E. , Al‐Quaddomi Suad A. , Mirza Kahvic , Ajrawi M. Tareq , Amir Thasneem , Dey Pranab , Francis, Issam M. 
Published: May 2007

AbstractMedullary thyroid carcinoma (MTC) is a relatively rare thyroid malignancy of C‐cell origin that secretes calcitonin. Although its varied cytomorphologic features are well described in literature, very little is mentioned about the morphologic manifestation of its secretory activity. This study, based on nine fine needle aspiration (FNA) samples from eight MTC patients, is an attempt to present the varied cytomorphologic features suggesting secretory activity in MTC as observed in Papanicolaou and MGG stained FNA smears and correlate them with the immunocytochemical (ICC) staining for calcitonin performed on FNA smears and the serum calcitonin values. The average number of cells in these nine samples was as follows: oval/triangular/plasmacytoid (56.7%), small round (23.6%), spindle‐shaped (12.7%), and miscellaneous (7.1%). The cytomorphological features suggesting secretory activity, viz., fine cytoplasmic vacuoles, azurophillic granules, marginal vacuoles, and intracytoplasmic lumina (ICL) with secretions were present in eight, eight, five, and six samples, respectively. Material likely to be amyloid, based on morphological features, was present extracellularly in three samples and both intracellularly and extracellularly in six samples. Immunocytochemically, all the nine samples stained for calcitonin and all the three stained for chromogranin showed positive cytoplasmic reaction in the neoplstic cells. The background amyloid (in six samples), the coarse cytoplasmic granules (in two samples), and the contents of ICL (in one sample) were found to be positively stained for calcitonin. The intracytoplasmic secretory material appeared to be diffusing out of some cells both in the routine MGG stained smears and in the smears stained for calcitonin. Histopathology reports of seven samples in six patients confirmed the cytodiagnosis of MTC in all. Baseline serum calcitonin values in three cases and postoperative serum calcitonin levels during follow‐up in three others were high. Thus, our study highlighted the morphological manifestations of secretory activity in MTC and the nature of secretory material as calcitonin, supported by immunocytochemical staining and serum calcitonin level. Diagn. Cytopathol. 2007;35:329–337. © 2007 Wiley‐Liss, Inc.
Fine‐needle aspiration cytology of medullary breast carcinoma: Report of two cases and review of the literature with emphasis on differential diagnosis
Authors: Racz Melinda M. , Pommier Rodney F. , Troxell Megan L. 
Published: May 2007

AbstractMedullary carcinoma is a rare variant of breast carcinoma with a relatively good clinical prognosis as strictly defined. Characteristic features on fine‐needle aspiration cytology (FNAC) allow medullary carcinoma to be considered in the cytologic differential diagnosis. We present two FNAC cases with such features, including high cellularity with clusters and single intact malignant cells, bizarre stripped nuclei with prominent nucleoli in a lymphoplasmacytic background, and illustrate one case in liquid‐based preparation. Surgical excision revealed that one patient had medullary carcinoma, while the second patient had high‐grade infiltrating ductal carcinoma. Breast FNAC samples with syncytial fragments, bizarre nuclei with prominent nucleoli, and a chronic inflammatory infiltrate should raise the possibility of medullary carcinoma. However, the differential diagnosis also includes high‐grade ductal carcinoma, lymphoma, or metastasis to breast or intramammary lymph nodes; thus, histopathologic analysis is required for definitive diagnosis. Diagn. Cytopathol. 2007;35:313–318. © 2007 Wiley‐Liss, Inc.
Critical and sensitive periods for reversing the effects of mechanosensory deprivation on behavior, nervous system, and development in Caenorhabditis elegans
Authors: Rai Susan , Rankin Catharine H. 
Published: May 2007

AbstractIn these studies the nematode Caenorhabditis elegans was used as a model to investigate ways to reverse the effects of mechanosensory deprivation on behavior and development. Rose et al. (J Neurosci 2005; 25:7159–7168) showed that worms reared in isolation responded significantly less to a mechanical tap stimulus, were significantly smaller, and expressed significantly lower levels of a postsynaptic glutamate receptor subunit on the command interneurons of the tap response circuit and a presynaptic vesicle marker in the tap sensory neurons compared with worms raised in groups. Here, brief mechanical stimulation at any time throughout development reversed the effects of isolation on the response to tap and on postsynaptic glutamate receptor expression on the command interneurons, suggesting there is no critical period for these measures. In contrast to the high level of plasticity in glutamate receptor subunit expression on the interneurons, low levels of stimulation only rescued vesicle expression in the tap sensory neurons early in development and progressively higher levels of stimulation were required as the worm developed, suggesting a sensitive period immediately after hatching, followed by a period of decreasing plasticity. Stimulation during the first three stages of larval development, but not later, rescued the effects of isolation on worm length, suggesting there is a critical period for this measure that ends in the third larval stage. These results indicate that different effects of early isolation required different amounts and/or timing of stimulation to be reversed. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007.
Generation of transgenic tendon reporters, ScxGFP and ScxAP, using regulatory elements of the scleraxis gene
Authors: Pryce Brian A. , Brent Ava E. , Murchison Nicholas D. , Tabin Clifford J. , Schweitzer Ronen 
Published: May 2007

AbstractDefects in tendon patterning and differentiation are seldom assessed in mouse mutants due to the difficulty in visualizing connective tissue structures. To facilitate tendon analysis, we have generated mouse lines harboring two different transgene reporters, alkaline phosphatase (AP) and green fluorescent protein (GFP), each expressed using regulatory elements derived from the endogenous Scleraxis (Scx) locus. Scx encodes a transcription factor expressed in all developing tendons and ligaments as well as in their progenitors. Both the ScxGFP and ScxAP transgenes are expressed in patterns recapitulating almost entirely the endogenous developmental expression of Scx including very robust expression in the tendons and ligaments. These reporter lines will facilitate isolation of tendon cells and phenotypic analysis of these tissues in a variety of genetic backgrounds. Developmental Dynamics, 2007. © 2007 Wiley‐Liss, Inc.
Functional impairment associated with bulimic behaviors in a community sample of men and women
Authors: Mond Jonathan M. , Hay Phillipa J. 
Published: May 2007

AbstractObjective:To examine functional impairment associated with bulimic behaviors in a community sample of men and women.Method:Binge eating, purging, fasting, extreme weight and shape concerns, and “days‐out‐of‐role” were assessed in a community sample of men (n = 1,290) and women (n = 1,757) aged 15–94 years.Results:Participants who reported regular eating disorder behaviors had higher levels of functional impairment than those who did not. This was the case for both men and women and for each of the behaviors assessed, although differences between purgers and nonpurgers were not statistically significant. Also in both men and women, participants who reported eating disorder behaviors and weight or shape concerns had higher levels of impairment than those who reported these behaviors in the absence of weight or shape concerns. In multivariate analysis, binge eating, fasting and weight or shape concerns all contributed to the likelihood of impairment in men, whereas only the presence of weight or shape concerns was significantly associated with impairment in women.Conclusion:Whereas bulimic behaviors are associated with elevated levels of functional impairment in both men and women, weight or shape concerns may be more central to the experience of this impairment in women. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
Assessment of binge eating in overweight youth using a questionnaire version of the child eating disorder examination with instructions
Authors: Goldschmidt Andrea B. , Doyle Angela Celio , Wilfley Denise E. 
Published: May 2007

AbstractObjective:Existing self‐report methods for assessing eating disorder (ED) symptoms in youth do not adequately measure binge eating and lack sufficient psychometric support. The Youth Eating Disorder Examination‐Questionnaire (YEDE‐Q), a self‐report version of the Child Eating Disorder Examination (ChEDE), was designed to assess the spectrum of ED psychopathology in youth.Method:The YEDE‐Q was compared to the ChEDE and the Questionnaire for Eating and Weight Patterns‐Adolescent version (QEWP‐A) in a sample of 35 overweight adolescents aged 12–17.Results:The YEDE‐Q showed significant agreement (ps < .001) with the ChEDE on all four subscale scores, the global score, and measurement of objective bulimic episodes. The YEDE‐Q and the QEWP‐A showed significant agreement (ps < .001) on the measurement of shape and weight concerns.Conclusion:The YEDE‐Q appears promising in the assessment of eating‐related pathology in overweight adolescents, but remains in need of validation in children and ED populations. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
Relative reinforcing value of exercise in inpatients with anorexia nervosa: Model development and pilot data
Authors: Schebendach Janet E. , Klein Diane A. , Foltin Richard W , Devlin Michael J. , Walsh B. Timothy 
Published: May 2007

AbstractObjective:This study sought to quantify, among patients hospitalized for the treatment of anorexia nervosa (AN), the reinforcing value of exercise, defined as the amount of work a patient would expend for the opportunity to exercise.Method:Sixteen inpatients with AN performed a computerized progressive ratio (PR) task for the opportunity to exercise for either 15 or 30 min, or a monetary voucher. Exercise “breakpoint” was calculated and compared with clinical measures.Results:Patients performed an average of 1134.4 (±751.2) button presses for exercise. Exercise breakpoint was significantly correlated with the Beck Depression Inventory (BDI; r = .728, p = .001), and there was a trend toward a correlation with the Commitment to Exercise Scale (CES; Davis, 1993; r = .490, p = .054).Conclusion:Results support the feasibility and potential utility of this novel application of the PR task to quantify the reinforcing value of exercise in AN. The association between exercise and depression is consistent with some prior studies in AN. The trend toward an association with CES scores suggests that breakpoint captures an aspect of the motivation for exercise in this population. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
Differential capacity of T cell priming in naive donors of promiscuous CD4+ T cell epitopes of HCV NS3 and Core proteins
Authors: Castelli Florence A. , Leleu Mélanie , Pouvelle‐Moratille Sandra , Farci Sandrine , Zarour Hassane M. , Andrieu Muriel , Auriault Claude , Ménez André , Georges Bertrand , Maillere Bernard 
Published: May 2007

AbstractTo understand the inter‐individual and virus‐independent variability of CD4+ T cell responses to HCV components, we evaluated the effect on these responses of HLA II molecules in uninfected healthy donors. Using HLA II‐specific binding assays, we identified, in the Core and NS3 proteins, 21 long fragments and 24 15‐mer peptides that bound to four to eight of the most preponderant HLA II molecules. We then evaluated the priming capacity of eight long promiscuous peptides in 12 HLA‐unrelated healthy donors. The NS3 1250–1264 peptide primed T cells in all the naive donors, while five others were stimulating in at least half of the individuals. We also report sequences that bind to multiple HLA II molecules but are weakly immunogenic. We therefore conclude that (i) broad HLA II specificity is only a prerequisite for a peptide to be stimulating in multiple individuals, and (ii) promiscuous peptides widely differ in their capacity to prime CD4+ T cells from uninfected healthy donors. We suggest that these priming differences result from inter‐individual variations in the peptide‐specific T cell repertoire. Interestingly, five of the most immunogenic peptides we identified correspond to frequently targeted T cell epitopes in infected patients.
Preferred Phosphorus Ylide Formation Upon Alkylation of Lithiobis(diphenylphosphanyl)acetonitrile
Authors: Braun Leonie , Kehr Gerald , Blömker Tobias , Fröhlich Roland , Erker Gerhard 
Published: May 2007

AbstractDeprotonation of the readily available chelate phosphane bis(diphenylphosphanyl)acetonitrile (6) leads to stabilized carbanion system 7. Lithiobis(diphenylphosphanyl)acetonitrile (7) features a unique thf‐stabilized monomeric structure in the crystal form with a short cyanonitrogen–Li contact. Alkylation of 7 with n‐alkyl bromides (R–Br, R = ethyl, n‐propyl, n‐butyl, n‐hexyl) takes place selectively at one phosphorus atom to yield stabilized ylides 8a–d (two examples characterized by X‐ray diffraction). Treatment of 7 with the more reactive alkylation agents methyl iodide or benzyl bromide results in alkylation at both phosphorus atoms to give delocalized bis(phosphonium)ylides 9a,b (both characterized by X‐ray diffraction). Similarly, the reaction of 7 with 1,3‐dibromopropane or 1,4‐dibromobutane yields six‐ and seven‐membered heterocyclic bis(phosphonium)ylides 10a,b, respectively. The spectroscopic characterization and X‐ray crystal structure analysis again indicate the presence of delocalized Ph2RP–C(CN)–PRPh2 substructures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)