bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial expression of the hsr‐omega (93D) gene in different tissues of drosophila melanogaster and identification of promoter elements controlling its developmental expression
Authors: Mutsuddi Mousumi , Lakhotia S. C. 
Published: May 2005

AbstractDevelopmental expression of the heat shock inducible non‐protein coding hsromega gene in several larval and adult tissues of Drosophila melanogaster was examined by in situ hybridization to transcripts in intact organs and by X‐gal staining in the germline transformants carrying the lacZ reporter gene under the control of hsromega promoter. This gene is expressed in a specific spatial pattern in all the larval and adult tissue types examined; however, its transcripts were specifically absent in certain gonadal cell types like the male as well as female gonial cells and in follicle cells and oocytes in ovary. All polytenised tissues like the prothoracic and salivary glands, certain regions of larval gut and the Malpighian tubules showed a greater abundance of hsr‐omega transcripts with a strong hybridization in nuclei. Our results with promoter deletion variant germline transformants suggest that a region between –346bp to –844bp upstream contains major regulatory element/s for developmental expression of this gene in most of the larval and adult tissues examined; however, this region is not sufficient for its normal expression in male and female reproductive systems. An analysis of the base sequence of the hsr‐omega promoter (upto –844bp) reveals putative ecdysone receptor element half‐sites and two GAGA factor binding sites which may be involved in its developmental expression and its ready inducibility. The widespread expression in most tissue types and the known lethality associated with its homozygous deletion, suggest that the variety of non‐protein coding transcripts of the hsromega gene have vital “house‐keeping” functions.
Identification of members of the HSP30 small heat shock protein family and characterization of their developmental regulation in heat‐shocked xenopus laevis embryos
Authors: Tam Ying , Heikkila John J. 
Published: May 2005

AbstractIn the present study we have characterized the synthesis of members of the HSP30 family during Xenopus laevis development using a polyclonal antipeptide antibody derived from the carboxyl end of HSP30C. Two‐dimensional PAGE/immunoblot analysis was unable to detect any heat‐inducible small HSPs in cleavage, blastula, gastrula, or neurula stage embryos. However, heat‐inducible accumulation of a single protein was first detectable in early tailbud embryos with an additional 5 HSPs at the late tailbud stage and a total of 13 small HSPs at the early tadpole stage. In the Xenopus A6 kidney epithelial cell line, a total of eight heat‐inducible small HSPs were detected by this antibody. Comparison of the pattern of protein synthesis in embryos and somatic cells revealed a number of common and unique heat inducible proteins in Xenopus embryos and cultured kidney epithelial cells. To specifically identify the protein product of the HSP30C gene, we made a chimeric gene construct with the Xenopus HSP30C coding sequence under the control of a constitutive promoter. This construct was microinjected into fertilized eggs and resulted in the premature and constitutive synthesis of the HSP30C protein in gastrula stage embryos. Through a series of mixing experiments, we were able to specifically identify the protein encoded by the HSP30C gene in embryos and somatic cells and to conclude that HSP30C synthesis was first heat‐inducible at the early tailbud stage of development. The differential pattern of heat‐inducible accumulation of members of the HSP30 family during Xenopus development suggests that these proteins may have distinct functions at specific embryonic stages during a stress response.
Inner‐Phase Reaction Dynamics: The Influence of Hemicarcerand Polarizability and Shape on the Potential Energy Surface of an Inner‐Phase Reaction
Authors: Sánchez Carrera Sigifredo , Kerdelhué Jean‐Luc , Langenwalter Kevin J. , Brown Neil , Warmuth Ralf 
Published: May 2005

AbstractThe thermal decomposition of six phenyldiazirine (2) hemicarceplexes and the spectroscopic properties of these hemicarceplexes, as well as those of one spiro[cyclobutabenzene‐1(2H),3′‐diazirine] (1) and one p‐tolyldiazirine (3) hemicarceplex, have been investigated in order to determine the effect of a hemicarcerand on the potential energy surface of an inner‐phase reaction. These hemicarceplexes have pentyl or phenethyl feet groups, three tetramethylene linkers and differ in the nature of one linker group X as follows: 1: X = (CH2)5; 2: X = (CH2)n (n = 2, 3, 4), (S,S)‐CH2CH[OC(CH3)O]CHCH2 ­and ortho‐CH2C6H4CH2; 3: X = (CH2)4. The effect of the linker group X on the structure of the phenyldiazirine hemicarceplexes was analyzed by MM2 force field calculations and leads to a change in the bending of the inner phase, which increases in the order (S,S)‐CH2CH[OC(CH3)O]CHCH2 > (CH2)4 > (CH2)3 > (CH2)2 > ortho‐CH2C6H4CH2 and to a shortening of the center‐to‐center distance between the two cavitands of the host, which decreases in the order (S,S)‐CH2CH[OC(CH3)O]CHCH2 < (CH2)4 < (CH2)3 < (CH2)2 < ortho‐CH2C6H4CH2. All hemicarceplexes show large red shifts of the diazirine n‐π*‐transition in their UV/Vis absorption spectra. From the red shifts and from plots of the n‐π*‐excitation energy of the free diazirines against the solvent polarizability P, the inner‐phase polarizability was estimated. P ranges from 0.39 to 0.58 and is larger than the polarizabilities of common organic solvents. A comparison of the activation parameters ΔH‡, TΔS‡, and ΔG‡ for the diazirine decomposition in the inner phase with those in the bulk phase shows that the hemicarcerand stabilizes the inner‐phase transition states enthalpically by ΔΔH‡ = 1.9–2.8 kcal/mol and destabilizes the transition states entropically by ΔTΔS‡ = 0.2 to 3.0 kcal/mol. The enthalpic stabilization is explained with dispersion interactions between the stretched C–N bonds in the transition state and the highly electron‐rich aryl units of the hemicarcerand. This is consistent with the high polarizability of the inner phase. The entropic destabilization of the inner‐phase transition states is explained with a greater loss of vibrational degrees of freedoms as the transition state is reached in the inner phase as compared to the more mobile bulk solvent cage. Furthermore, the entropic destabilization decreases with an increased bending of the inner phase. This is explained with an induced‐fit model. An increased hemicarcerand bending leads to an improved fit between the inner phase and the bend transition states, which reduces the loss of vibrational degrees of freedom as the transition states are reached. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis of Spirocyclopropanated Analogues of Iprodione
Authors: Brackmann Farina , Es‐Sayed Mazen , de Meijere Armin 
Published: May 2005

AbstractMethyl 1‐(tert‐butoxycarbonylamino)cyclopropanecarboxylate (9) was converted into the spirocyclopropanated five‐membered ring analogue 7a of Iprodione (1) in five steps with an overall yield of 28 %. The spirocyclopropanated five‐membered ring analogue 8a was prepared from tert‐butyl N‐[1‐(hydroxymethyl)cyclopropyl]carbamate (10) in five steps with an overall yield of 19 %. En route to the spirocyclopropanated six‐membered ring analogues of Iprodione (1), the oxalic acid diamides 5b and 6b could be obtained starting from 9 or 10 in 33 or 19 % yield, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Calix[5]‐ and Calix[8]arenes Bridged with Heterocycles
Authors: Konrad Serge , Näther Christian , Lüning Ulrich 
Published: May 2005

AbstractCalix[5]arene (2) and calix[8]arene (4) reacted with bis(bromo­methyl)‐substituted heterocycles such as pyridine and 1,10‐phenanthroline to give [1+1] condensation products 10 and 16–18 (bridged bimacrocycles) and [2+1] dicalixarenes 11, 13 and 14, all of which were fully characterized. Although the bridging capability of both bridging units 5 and 6 is surprisingly similar, calix[5]arene (2) could only be bridged with the pyridine derivatives 5. With calix[8]arene (4), the 1,10‐phenanthroline bridging reagent 6 gave a cleaner product spectrum than the pyridine reagent 5. The 1,10‐phenanthroline‐bridged calix[8]arene 16 was characterized by X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis of Bromo‐ and Iodohydrins from Deactivated Alkenes by Use ofN‐Bromo‐ and N‐Iodosaccharin
Authors: Urankar Damijana , Rutar Irena , Modec Barbara , Dolenc Darko 
Published: May 2005

AbstractN‐Bromo and N‐iodosaccharin react with electron‐deficient alkenes such as α,β‐unsaturated ketones, acids, esters and nitriles in aqueous organic solvents, yielding the corresponding halohydrins in good yields. The reactions take place at room temperature, mostly within short reaction times and with high antistereoselectivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Highly Chemoselective Multicomponent Biginelli‐Type Condensations of Cycloalkanones, Urea or Thiourea and Aldehydes
Authors: Zhu Yu‐lin , Huang Shen‐lin , Pan Yuan‐jiang 
Published: May 2005

AbstractThe classical Biginelli reaction is considerably extended by use of cycloalkanones instead of 1,3‐dicarbonyl compounds. Use of TMSCl as a Lewis acid allowed one‐pot chemoselective multicomponent Biginelli reactions between cycloalkanones, urea or thiourea, and aldehydes. Under similar reaction conditions, thiourea exhibited different behavior to urea, and aliphatic aldehydes showed lower reactivity than aromatic aldehydes. A possible mechanism to account for the reaction is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Total Synthesis of (±)‐Pumiliotoxin C: An Electrochemical Approach
Authors: Girard Nicolas , Hurvois Jean‐Pierre , Moinet Claude , Toupet Loic 
Published: May 2005

AbstractThe total stereoselective synthesis of the decahydroquinoline alkaloid (±)‐pumiliotoxin C (cis‐195A, 1) is described. The compound was prepared in 15 steps from the commercially available 4‐piperidone ethylene ketal 2, in an overall 5 % yield. New C–C bonds in the α position relative to the nitrogen atom were formed by the metalation of aminonitriles 4 and 15, which were themselves prepared electrochemically. The ease of this synthesis shows that the N‐aryl group is an efficient nitrogen‐protecting group that can be removed in the last step through a Birch dearomatization. In addition, the aryl substituent serves as an efficient activator of the nitrogen atom during the elaboration of aminonitriles 4 and 15. The oxygen atom of the keto carbonyl group in octahydroquinolinone 10 was removed by an unprecedented two‐step method involving a Shapiro reaction and a palladium‐catalyzed reduction of the intermediate alkene 13. Finally, the expected stereospecific alkylation–hydride reduction process of the cis‐fused aminonitrile 15 established the trans relationship between the propyl group at C‐2 and the methyl substituent at C‐5. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Absolute Configuration of the Fungal Metabolite Spirolaxine
Authors: Bava Adriana , Clericuzio Marco , Giannini Giuseppe , Malpezzi Luciana , Valdo Meille Stefano , Nasini Gianluca 
Published: May 2005

AbstractThe relative stereochemistry of the four stereocentres of spirolaxine 1, a bioactive 6,5‐spiroacetal phthalide secondary metabolite, was determined through single‐crystal X‐ray analysis. Its absolute configuration was determined by circular dichroism; the experimental spectrum of spirolaxine is in good agreement with that evaluated by means of DeVoe coupled‐oscillator calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Highly Efficient Catalytic Nitration of Phenolic Compounds by Nitric Acid with a Recoverable and Reusable Zr or Hf Oxychloride Complex and KSF
Authors: Shi Min , Cui Shi‐Cong , Yin Wan‐Po 
Published: May 2005

AbstractPhenolic compounds can be nitrated with 60 % nitric acid (1.2 equiv.) in the presence of catalytic amounts of a Zr or Hf oxychloride complex and montmorillonite KSF to give the corresponding nitrated products in good yields in a heterogeneous catalytic system. The co‐catalyst and montmorillonite can be easily recovered and reused in the next batch of nitration. This is a practical process for the nitration of phenolic compounds in a clean way. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Why Do Peroxomolybdenum Complexes Chemoselectively Oxidize the Sulfur Centers of Unsaturated Sulfides and Sulfoxides? A DFT Analysis
Authors: Sensato Fabrício R. , Custodio Rogério , Longo Elson , Safont Vicent S. , Andrés Juan 
Published: May 2005

AbstractThe reasons why oxo‐peroxo molybdenum complexes chemoselectively oxidize unsaturated sulfides to the corresponding sulfoxides and these to sulfones without any epoxidation of the electron‐rich double bond were elucidated by transition state theory and density functional calculations at the B3LYP level. For the diperoxo model complex with the structure MoO(η2‐O2)2OPH3 and for allyl methyl sulfide as a model of unsaturated sulfides, the calculations show that the oxygen transfer process from the peroxomolybdenum complex to the sulfur center requires a lower free activation energy (ΔG‡ = 19.0 kcal mol–1) than the attack on the double bond moiety (ΔG‡ = 26.4 kcal mol–1) of the unsaturated sulfide. Subsequent oxidation of allyl methyl sulfoxide at the sulfinyl group to yield the corresponding sulfone also requires a lower activation energy (ΔG‡ = 21.5 kcal mol–1) thanthe corresponding epoxidation process (ΔG‡ = 27.7 kcal mol–1),yielding 2,3‐epoxypropyl methyl sulfoxide. These results unambiguously account for these complexes’ excellent chemoselectivity towards the sulfur groups in unsaturated sulfides and sulfoxides, as has been observed experimentally. On the basis of SCRF calculations, the level of chemoselectivity is predicted to diminish with increasing solvent polarity. Charge decomposition analysis and the orbital interaction model reveal that unsaturated sulfides with reaction sites carrying lone pair and π electrons behave as nucleophiles toward the electrophilic peroxo oxygen group. The origin of the chemoselectivity is ascribed to the fact that the electronic state related to the sulfur lone pair (HOMO) lies 1.2 eV above that associated with the π electrons (HOMO–1). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Estimation of charge trapping in bilayers of coducting polymers composed of polypyrrole and poly(N‐methylpyrrole)
Authors: Maksymiuk Krzysztof 
Published: May 2005

AbstractCharge trapping effects were studied in bilayers of conducting polymers composed of poly(N‐methylpyrrole) (PMPy) and polypyrrole (PPy), by comparing redox charges of the polymer [Q(ox/red)] obtained by integration of cyclic voltammetric and chronoamperometric curves for single films and bilayers with variable thickness of both components. Charge trapping factors, TF, for PMPy(inner layer)/PPy(outer layer) bilayers were determined using the definition: TF = 1 ‐ Q(ox/red)/Q(ox/red)PPy where Q(ox/red) is redox charge of PPy in the bilayer, Q(ox/red)ppy relates to the charge for a single PPy film of the same thickness as that in the bilayer. Since the formal potential of PMPy is higher than that of PPy, the outer PPy film cannot be entirely reduced due to low conductivity of PMPy at negative potentials. The estimated charge trapping factor is independent of the outer layer thickness, it depends, however on the thickness of the inner film. For the reverse sequence of polymers, PPy/PMPy, charge trapping was not observed. Modification of the outer PPy layer by immobilized poly(4‐styrenesulfonate) anions changes the response of the bilayer due to low permeability of the cation‐exchanging outer polymer to anions. Therefore perchlorate anions compensating charge of PMPy film were found to be entrapped in the polymer matrix under conditions of cyclic voltammetry.
Use of different fluorochromes for monitoring protein elution and transfer
Authors: Szewczyk Boguslaw , Bienkowska‐Szewczyk Krystyna , Kozloff Lloyd M. 
Published: May 2005

AbstractProtein molecular weight standards labeled with different fluorochromes were tested for their usefulness in following the protein transfer from sodium dodecyl sulfate‐polyacrylamide gels to nitrocellulose and for electro‐elution of proteins from polyacrylamide gels. Dichlorotriazynylaminofluorescein labeled proteins appear to be useful for both purposes as they are stable, their detection sensitivity was high (about 10 ng of protein on nitrocellulose) and the coupling of the fluorochrome did not appreciably change the molecular weight of any protein examined. On the other hand, proteins labeled with tetramethylrhodamine isothiocyanate, or its heterocyclic derivative, were of limited usefulness as standards. Labeled proteins of molecular weight below 20 kDa formed diffuse bands on gels. Therefore, these particular fluorescent protein standards appear to be useful in following the elution from gels, or as references on nitrocellulose, only for proteins larger than 20–25 kDa.
Sodium dodecyl sulfate electrophoresis in the first dimension and isoelectric focusing in the second dimension in a single thin‐layer gel, followed by activity stain for glycosyltransferases
Authors: Mukasa Hidehiko , Tsumori Hideaki , Shimamura Atsunari 
Published: May 2005

AbstractA method has been developed for the two‐dimensional separation of proteins in a single thin‐layer gel, using sodium dodecyl sulfate‐polyacrylamide gel electrophoresis in the first dimension and isoelectric focusing in the second dimension. After two‐dimensional electrophoresis of concentrated culture supernatants from Streptococcus mutans, the gels were directly stained with Coomassie Brilliant Blue R‐250 for protein and with periodic acid‐Schiff base reagent for glycoprotein. Glycosyl‐transferases were detected by incubating the gels in a sucrose‐containing buffer, either by visual observation of white spots of the product polysaccharides or by periodic acid‐Schiff staining of the products. All the procedures, including the staining steps, were done in a single gellayer covalently bound to a glass plate. The efficient removal of sodium dodecyl sulfate and renaturation of glycosyltransferases in the gel layers rendered this a simplified and rapid method for the relative molecular mass and isoelectric point determinations in the crude preparations.
Heat release rates from samples of polymethlmethacrylate and polystyrene burning in normal air
Authors: Tewarson A. 
Published: May 2005

AbstractResults are presented for mass generation rates of major combustion products (CO2, CO, total hydrocarbons and smoke particulates) and heat release rates from samples of polymethylmethacrylate and polystyrene burning in normal air under varying magnitudes of externally applied radiant heat flux. In the experiments mass generation rates of products and convective heat release rates are measured and, from heat and mass balance, actual and radiative rate of heat release, as well as heat that is not released due to incompleteness of combustion, are calculated. From the data, 99% of the rate of the theoretical heat release for complete combustion can be accounted for. In some cases the experimentally derived heat release rate was less than half that predicted from mass loss rate (assuming complete combustion). This ‘combustion efficiency’ decreased strongly with increasing externally applied radiant flux, and was always much lower for polystrene than for polymethylmethacrylate. At the ‘deal’ condition, defined as a condition where heat losses have been compensated and where the mass burning rate of polystyrene is 1.44 times the rate for polymethylmethacrylate, polystyrene generates 6.60 times more CO, 7.83 times more smoke particulates, and the radiative rate of heat release is 1.75 times more than that of polymethylmethacrylate.
Smoke characteristics of coal‐lined tunnel fires
Authors: Cashdollar Kenneth L. , Singer Joseph M. , Lee Calvin K. , Litton Charles D. 
Published: May 2005

AbstractCharacteristics of smoke particulates generated from a coal fire in a ventilated model tunnel were investigated by laser optical transmission and by electron microscopy. Average particle diameter and mass concentration of the smoke were determined as a function of the temperature and stoichimoetry of the coal tunnel fire. Smoke particle sizes ranged from 0.2 to 0.9 μm, with larger particle sizes associated with higher smoke concentrations. These coal smoke data are relevant to several aspects of underground mine safety including the development and location of smoke detection instruments, the understanding of the fire (toxic fume) hazard, and the development of new fire protection and control techniques.
Genetic admixture and asthma‐related phenotypes in Mexican American and Puerto Rican asthmatics
Authors: Salari Keyan , Choudhry Shweta , Tang Hua , Naqvi Mariam , Lind Denise , Avila Pedro C. , Coyle Natasha E. , Ung Ngim , Nazario Sylvette , Casal Jesus , Torres‐Palacios Alfonso , Clark Suzanne , Phong Angie , Gomez Ivan , Matallana Henry , Pérez‐Stable Eliseo J. , Shriver Mark D. , Kwok Pui‐Yan , Sheppard Dean , Rodriguez‐Cintron William , Risch Neil J. , Burchard Esteban González , Ziv Elad 
Published: May 2005

AbstractGenetic association studies in admixed populations may be biased if individual ancestry varies within the population and the phenotype of interest is associated with ancestry. However, recently admixed populations also offer potential benefits in association studies since markers informative for ancestry may be in linkage disequilibrium across large distances. In particular, the enhanced LD in admixed populations may be used to identify alleles that underlie a genetically determined difference in a phenotype between two ancestral populations. Asthma is known to have different prevalence and severity among ancestrally distinct populations. We investigated several asthma‐related phenotypes in two ancestrally admixed populations: Mexican Americans and Puerto Ricans. We used ancestry informative markers to estimate the individual ancestry of 181 Mexican American asthmatics and 181 Puerto Rican asthmatics and tested whether individual ancestry is associated with any of these phenotypes independently of known environmental factors. We found an association between higher European ancestry and more severe asthma as measured by both forced expiratory volume at 1 second (r=−0.21, p=0.005) and by a clinical assessment of severity among Mexican Americans (OR: 1.55; 95% CI 1.25 to 1.93). We found no significant associations between ancestry and severity or drug responsiveness among Puerto Ricans. These results suggest that asthma severity may be influenced by genetic factors differentiating Europeans and Native Americans in Mexican Americans, although differing results for Puerto Ricans require further investigation. Genet. Epidemiol. 2005. © 2005 Wiley‐Liss, Inc.