bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anti‐sense‐mediated inhibition of expression of the novel striated tropomyosin isoform TPM1κ disrupts myofibril organization in embryonic axolotl hearts
Authors: Zajdel Robert W. , Denz Christopher R. , Narshi Aruna , Dube Syamalima , Dube Dipak K. 
Published: April 2005

AbstractStriated muscle tropomyosin (TM) is described as containing ten exons; 1a, 2b, 3, 4, 5, 6b, 7, 8, and 9a/b. Exon 9a/b has critical troponin binding domains and is found in striated muscle isoforms. We have recently discovered a smooth (exon 2a)/striated (exons 9a/b) isoform expressed in amphibian, avian, and mammalian hearts, designated as an isoform of the TPM1 gene (TPM1κ). TPM1κ expression was blocked in whole embryonic axolotl heart by transfection of exon‐specific anti‐sense oligonucleotide. Reverse transcriptase polymerase chain reaction (RT‐PCR) confirmed lower transcript expression of TPM1κ and in vitro analysis confirmed the specificity of the TPM1κ anti‐sense oligonucleotide. Altered expression of the novel TM isoform disrupted myofibril structure and function in embryonic hearts. © 2005 Wiley‐Liss, Inc.
Effect of N‐cadherin misexpression by the mammary epithelium in mice
Authors: Knudsen Karen A. , Sauer Christa , Johnson Keith R. , Wheelock Margaret J. 
Published: April 2005

AbstractN‐cadherin is not typically expressed by epithelial cells. However, it is detected in breast cancers and increases tumor cell migration and invasion in vitro. To explore its misexpression, we generated transgenic mice with N‐cadherin in the mammary epithelium. Mammary glands appeared normal and no tumors arose spontaneously. To investigate N‐cadherin misexpression in mammary tumors, neu was overexpressed through breeding. Tumors developed in +/neu and N‐cadherin/neu mice, although few tumors in bitransgenic mice expressed N‐cadherin, and they did not differ from N‐cadherin‐negative tumors. © 2005 Wiley‐Liss, Inc.
Comparison of the Raman spectra of natural and synthetic K‐ and Na‐jarosites at 298 and 77 K
Authors: Frost Ray L. , Wills Rachael‐Anne , Weier Matt L. , Martens Wayde 
Published: April 2005

AbstractRaman spectroscopy at 298 and 77 K was used to characterize synthetic and natural jarosites of formula M2(Fe3+)6(SO4)4(OH)12, where M = K or Na. The natural jarosites are characterized by a well‐defined hydroxyl stretching pattern, in contrast to that of the synthetic jarosites. This difference is attributed to differences in hydrogen bonding in the mineral. Multiple Raman OH stretching bands are indicative of non‐equivalent OH units in the structure. Jarosites are characterized by an intense, sharp band between 1007 and 1010 cm−1 attributed to the sulfate symmetric stretching mode. The bandwidth for K‐jarosite is 4.4 cm−1 at 298 K and 3.6 cm−1 at 77 K in comparison with the values for synthetic jarosite of 10.0 (298 K) and 7.3 cm−1 (77 K). Differences in the spectra between the natural and synthetic jarosites are found. Reasons for these differences in the spectra are provided. Copyright © 2005 John Wiley & Sons, Ltd.
RAFT Polymerization of Methyl Acrylate in Carbon Dioxide
Authors: Arita Toshihiko , Beuermann Sabine , Buback Michael , Vana Philipp 
Published: April 2005

AbstractSummary:Reversible addition fragmentation chain transfer (RAFT) polymerizations of methyl acrylate (MA) in solution containing either 22 vol.‐% CO2or toluene were performed at 80 °C and 300 bar using cumyl dithiobenzoate (CDB) at concentrations between 1.8 × 10−3to 2.5 × 10−2mol · L−1as the RAFT agent. Product molecular weight distributions and average molecular weights indicated the successful control of MA polymerization in CO2, even at low CDB concentrations. RAFT polymerization rates were strongly retarded by CDB and were lower in CO2than in toluene solution. The enhanced fluidity associated with the addition of CO2to the polymerizing system provided access to mechanistic details of RAFT polymerization. The data of the present study into MA, together with our recent results on RAFT polymerization of styrene in solution of CO2and of toluene, suggest that self‐termination of intermediate RAFT radicals is responsible for retardation in case of high concentrations of this intermediate and in case of enhanced fluidity, which may be achieved by polymerization in solution of CO2.magnified image
Safety in Emulsion Polymerization Reactors: An Experimental Study
Authors: Azpeitia Maider , Leiza Jose R. , Asua Jose M. 
Published: April 2005

AbstractSummary: The risk parameters of the high‐solids‐content emulsion copolymerization of vinyl acetate/butyl acrylate/acrylic acid (78.5/18.5/3 wt.‐%) were studied. The effect of the polymer/monomer ratio, the total solids content, the initiator/monomer ratio, the non‐swollen polymer particle size, and the process temperature on the onset temperature for runaway, the adiabatic temperature increase, and the maximum temperature and pressure achieved was studied. These data are needed to determine the safety limits for the variables of this system considering the worst case scenario; namely, a runaway reaction under adiabatic conditions. It was found that the onset temperature is always below the typical process temperature for this system (70–80 °C). Therefore, in the case of a cooling system failure (i.e., electrical failure) the runaway reaction will take place. Relatively high pressures (up to 6 bar) were monitored during the runaway.Evolution of the maximum pressures reached during all the experiments versus the polymer‐to‐monomer ratio ‘r’ and the process temperature ‘Twork’.magnified imageEvolution of the maximum pressures reached during all the experiments versus the polymer‐to‐monomer ratio ‘r’ and the process temperature ‘Twork’.
Performance measures in tax administration: Chile as a case study
Authors: Serra Pablo 
Published: April 2005

AbstractThe article proposes a set of tax administration performance measures and contrasts them with measures actually used by the Chilean tax administration agency. The goals assumed for the tax administration agency (TA) are to maximize tax revenue collection and provide quality services to taxpayers. Ideal performance measures (PMs) would measure the deviation of actual outcome from a best‐practice standard, given the value of all variables affecting organisation performance that are outside management control. The key challenge is to build and calculate these best‐practice outcomes. In Chile the PM in use, for the first goal, is the ratio of actual to potential tax revenue collection. This PM does adjust revenue collection for variations in the tax structure and rate, but it fails to control other variables that affect performance such as the TA budget and per capita income. The PM in use, for the second goal, is taxpayer satisfaction measured through sample surveys. This seems the appropriate PM, as quality of taxpayer services depends directly on the TA efforts to improve them. Copyright © 2005 John Wiley & Sons, Ltd.
Preparation and characterization of a novel biodegradable poly(p‐dioxanone)/montmorillonite nanocomposite
Authors: Huang Fu‐Yun , Wang Yu‐Zhong , Wang Xiu‐Li , Yang Ke‐Ke , Zhou Qian , Ding Song‐Dong 
Published: April 2005

AbstractPoly(p‐dioxanone) (PPDO)/montmorillonite nanocomposites were prepared through the in situ ring‐opening polymerization of p‐dioxanone (PDO) and three types of montmorillonites (natural sodium montmorillonite, montmorillonite modified by octadecyltrimethyl ammonium chloride, and montmorillonite modified by hydroxyethylhexadecyldimethyl ammonium bromine) in the presence of triethylaluminum. Montmorillonite could accelerate the polymerization of PDO, and the viscosity‐average molecular weight of PPDO could reach 44,900 g/mol in 0.5 h. A nucleating effect of montmorillonite was observed, and the crystallization temperature of PPDO was increased by 18 °C. All three montmorillonites could improve the thermal stability of PPDO and increase the glass‐transition and melting temperatures of PPDO. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2298‐2303, 2005
Azobenzene‐based initiator for atom transfer radical polymerization of methyl methacrylate
Authors: Wang Gang , Zhu Xiulin , Zhenping Cheng , Zhu Jian 
Published: April 2005

Abstract2‐Bromopropionic acid 2‐(4‐phenylazophenyl)ethyl ester, 2‐bromopropionic acid 6‐(4‐phenylazophenoxy)hexyl ester (BPA6), 2‐bromopropionic acid‐(4‐phenylazoanilide), and 2‐bromopropionic acid 4‐[4‐(2‐bromopropionyloxy)phenylazo]phenyl ester (BPPE) were used as initiators with monofunctional or difunctional azobenzene for the heterogeneous atom transfer radical polymerization of methyl methacrylate with a copper(I) chloride/N,N,N′,N″,N″‐pentamethyldiethylenetriamine catalytic system. The rates of polymerizations exhibited first‐order kinetics with respect to the monomer, and a linear increase in the number‐average molecular weight with increasing monomer conversion was observed for these initiation systems. The polydispersity indices of the polymer were relatively low (1.15–1.44) up to high conversions in all cases. The fastest rate of polymerization and the highest initiation efficiency were achieved with BPA6, and this could be explained by the longer distance between the halogen and azobenzene groups and the better solubility of the BPA6 initiator. The redshifting of the UV absorptions of the polymers only occurred for the BPPE‐initiated system. The intensity of the UV absorptions of the polymers were weaker than those of the corresponding initiators in chloroform and decreased with the increasing molecular weights of the polymers in all cases. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2358–2367, 2005
Insecticidal activity of the pyrimidine nucleoside analogue (E)‐5‐(2‐bromovinyl)‐2′‐deoxyuridine (BVDU)
Authors: Breuer Michael , De Loof Arnold , Balzarini Jan , Huybrechts Roger 
Published: April 2005

AbstractThe insecticidal activity of the antiherpetic agent (E)‐5‐(2‐bromovinyl)‐2′‐deoxyuridine (BVDU) was assessed in in vivo assays against the fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera, Noctuidae). BVDU, mixed into an artificial diet, caused a variety of effects, depending on the concentration used. Compared with controls, food intake was lower, larval growth was retarded and larval development was prolonged. The treated larvae formed smaller pupae and the hatching moths often showed morphogenetic defects. A higher mortality could be found in larval and pupal stages and was generally caused by moult disruption. A choice assay showed that BVDU has very slight feeding‐deterrent properties, which only partly explain the toxic effects. The agent most probably acts through its cytostatic activity that has been described previously using cell lines of different insect species. Copyright © 2005 Society of Chemical Industry
A molecular model to explain paclitaxel and docetaxel sensitivity changes through adduct formation with primary amines in electrospray ionization mass spectrometry
Authors: Iyer Sunil S. , Gao Songmei , Zhang Zong‐Ping , Kellogg Glen E. , Karnes H. Thomas 
Published: April 2005

AbstractThe objective of this study was to adopt a molecular modeling approach to understand changes in signal intensity due to adduct formation with short‐chain alkylamines for two anticancer agents, paclitaxel and docetaxel, during electrospray mass spectrometric analysis. We describe a simple and intuitive modeling procedure using a comparison of hydropathic interaction (HINT) scores to explain differences in responses of amine adducts formed with the two analytes. The responses of paclitaxel and docetaxel were generally enhanced considerably (up to ∼500% in some instances) on adding the amines. However, for the docetaxel adduct formed with added decylamine in the mobile phase, the response dropped by 32%. A mechanistic understanding for this behavior is proposed, and binding scores calculated from corresponding molecular models were found to be consistent with the trend obtained from mass spectrometric data. Copyright © 2005 John Wiley & Sons, Ltd.
13C and 18O isotopic analysis to determine the origin of L‐tartaric acid
Authors: Serra F. , Reniero F. , Guillou C. G. , Moreno J. M. , Marinas J. M. , Vanhaecke F. 
Published: April 2005

AbstractDue to the ever‐increasing amount of attention paid to the ‘naturalness’ of ingredients in food and beverages by both consumers and controlling authorities, the search for suitable methods for the characterisation of origin is of primary importance. Within the European Community the wine production industry is often faced with the problem of origin control of tartaric acid. This has led to the decision that only L‐tartaric acid extracted from grapes (therefore natural) should be used. In order to implement these regulations, a screening of different techniques has been carried out to assess the methodology that best identifies the origin of the tartaric acid. It has already been indicated in previous scientific literature that isotope ratio mass spectrometry is an ideal technique for this type of identification. In this paper we present the results obtained for the measurement of the isotope ratios of carbon‐13 and oxygen‐18 of natural and synthetic samples of L‐tartaric acid considering also natural samples of different geographical origin and years of production. Copyright © 2005 John Wiley & Sons, Ltd.
In‐source fragmentation and analysis of polysaccharides by capillary electrophoresis/mass spectrometry
Authors: Li Jianjun , Wang Zhan , Altman Eleonora 
Published: April 2005

AbstractIn order to develop a robust and easy‐to‐use technique for characterization of bacterial polysaccharides, a pseudo‐hydrolysis strategy was investigated. Based on in‐source collision‐induced dissociation, polysaccharide molecular ions were fragmented within the orifice‐skimmer region of an electrospray ionization (ESI) mass spectrometer. The fragment ions thus generated were then analyzed similarly to the conventional ESI mass spectrometry approach. MS/MS scanning was applied to obtain product‐ion spectra of the primary fragments for sequencing. To further improve the sensitivity and separation of polysaccharides from other components in the samples, a pressure‐assisted capillary electrophoresis/mass spectrometry (CE/MS) system was employed. Using bacterial polysaccharides as model compounds, the mass spectra obtained for polysaccharide repeating units generated through chemical hydrolysis and in‐source fragmentation were directly compared, both in positive and negative ion modes. With the additional separation of impurities provided by CE, the success of this technique has been demonstrated for structural analysis of O‐chain polysaccharides (O‐PS) and capsular polysaccharides (CPS). In‐source fragmentation was applied to promote the formation of structurally relevant repeating units of heterogeneous CPS that would remain undetected using conventional ESI conditions. This approach was proven to be particularly useful for probing the subtle structural differences in monosaccharide composition and functionalities arising across bacterial serotypes. Copyright © 2005 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Hydrophilic interaction liquid chromatography with tandem mass spectrometry for the determination of underivatized dencichine (β‐N‐oxalyl‐L‐α,β‐diaminopropionic acid) in Panax medicinal plant species
Authors: Koh Hwee‐Ling , Lau Aik‐Jiang , Chan Eric Chun‐Yong 
Published: April 2005

AbstractDencichine (β‐N‐oxalyl‐L‐α,β‐diaminopropionic acid) is a haemostatic agent present in important Chinese medicinal herbs such as Panax notoginseng, as well as other Panax species. It is also a reported neurotoxic agent found in Lathyrus sativus (grass pea seed). A selective analytical method incorporating hydrophilic interaction chromatography with positive electrospray ionization tandem mass spectrometry (HILIC/ESI‐MS/MS), for the analysis of dencichine in Panax plant species, was developed. Using multiple reaction monitoring (MRM) mode, underivatized dencichine, a small and highly polar compound, was selectively detected and quantified. The contents of dencichine in raw and steamed Panax notoginseng roots, 11 pairs of raw and steamed P. notoginseng herbal products, Panax ginseng roots, and Panax quinquefolium roots, were analyzed and compared. Optimal sensitivity of 0.3 ppm (detection limit) and 1.5 ppm (quantification limit) was achieved. The method was rapid (≤5 min), with the HILIC peak eluting at about 1 min. Steamed P. notoginseng samples were found to contain less dencichine than the corresponding raw samples, and there were also differences among the three Panax species; raw P. ginseng and P. quinquefolium contained less dencichine than the raw P. notoginseng species. This rapid and specific method may be applied to the quantification of dencichine in complex medicinal plants and their products. Copyright © 2005 John Wiley & Sons, Ltd.
Synthese und Struktur gemischtvalenter Galliumsubhalogenide: Molekulare, donorstabilisierte Ga5X7‐Spezies (X = Cl, Br)
Authors: Duan Taike , Stößer Gregor , Schnöckel Hansgeorg 
Published: April 2005

AbstractSynthesis and Structure of mixed‐valent Gallium Subhalides: Molecular, donor‐stabilized Ga5X7 Species (X = Cl, Br)Caused by partial disproportionation, metastable GaX‐solutions (X = Cl, Br) contain small amounts of GaX3 species. They react via insertion of GaX to Ga2X4 and Ga5X7 entities. In contrast to Ga2X4, only one example has been isolated so far for the latter one: [Ga5Cl7·5Et2O]. Variation of the preparation conditions (e.g. temperature, amount and kind of the donor molecule) now leads to 4 further Ga5X7 species. In three of those a centered Ga5 tetrahedron is icosahedrically (distorted) coordinated by 12 atoms (halogen atoms resp. atoms of the donor ligand). The principal importance of these Ga5X7 species especially for the disproportionation process is discussed.
Helical Bipyrazole Networks Conditioned by Hydrothermal Crystallization
Authors: Domasevitch Konstantin V. , Boldog Ishtvan , Rusanov Eduard B. , Hunger Jens , Blaurock Steffen , Schröder Martin , Sieler Joachim 
Published: April 2005

AbstractAngular structure of 3,3′,5,5′‐tetramethyl‐4,4′‐bipyrazole tecton (Me4bpz) supports multiple helical strands in a series of coordination and hydrogen bonded polymers prepared using hydrothermal technique. Compounds reveal a variety of helical architectures and exist in the forms of double helicate Ag(Me4bpz)(PO2F2), two‐dimensional network formed by inter‐connection of the helices Ag2(Me4bpz)3(CF3CO2)2, interpenetrated two‐dimensional networks by interconnection of double helices Ag4(Me4bpz)5(NO3)4 · 2H2O and triple helicate formed by NH‒‒‒N hydrogen bonded bipyrazole molecules in structure Me4bpz·H2O.Coordination polymers Ag(Me4bpz)X ((X = ClO4−, CF3SO3−, C2F5CO2−) adopt simpler chain‐like structure. In all coordination compounds the bipyrazole acts as a bridging neutral group and connects two silver atoms at the distances of 9.44–9.94Å.
Synthese und Kristallstruktur von heteronuklearen Metallkomplexen mit Nitridobrücken Re≡N‐Ni, Re≡N‐Pt, Os≡N‐Rh und Os≡N‐Ir
Authors: Morrogh Daniel , Galceran Mestres Montserrat , Niquet Elke , Barboza da Silva Carlos F. , Santos Saez Abel , Schwarz Simon , Strähle Joachim 
Published: April 2005

AbstractSynthesis and Crystal Structure of Heteronuclear Metal Complexes with Nitrido Bridges Re≡N‐Ni, Re≡N‐Pt, Os≡N‐Rh, and Os≡N‐IrThe heteronuclear complex [(Me2PhP)3Br2Re≡N‐NiBr2(OPMe2Ph)] (1) is obtained by the reaction of [ReNBr2(PMe2Ph)3] with NiBr2 in tetrahydrofuran in form of dark green, air sensitive crystals crystallizing in the monoclinic space group P21/n with a = 961.44(9), b = 3692.6(4), c = 1177.8(2) pm, β = 103.42(1)°, and Z = 4. In the dinuclear complex the complex fragment [NiBr2(OPMe2Ph)] is connected by an asymmetric nitrido bridge Re≡N‐Ni with the nitrido complex [ReNBr2(PMe2Ph)3], such that the Ni atom achieves a tetrahedral coordination. The nitrido bridge is characterized by a bond angle Re‐N‐Ni of 172.7(7)° and distances Re‐N = 169(1) and Ni‐N = 195.0(9) pm.The reaction of [ReNCl2(PMe2Ph)3] with PtCl4 in THF proceeds under reduction of PtIV to yield air stable, brown crystals of [{(Me2PhP)3Cl2Re≡N}2PtCl2] (2) with the monoclinic space group P21/c and a = 1241.3(1), b = 1734.0(1), c = 1369.7(1) pm, β = 101.32(1)°, and Z = 2. The divalent Pt atom exhibits a square planar coordination with the two rhenium(V) nitrido complexes coordinated by nitrido bridges Re≡N‐Pt in trans position. The distances in the virtually linear nitrido bridge (Re‐N‐Pt = 174.0(3)°) are Re‐N = 170.6(5) pm and Pt‐N = 196.4(5) pm.The nitrido complex [OsNCl3(AsPh3)2] reacts with [Rh(μ‐Cl)(COD)]2 in CH2Cl2 to yield [(Ph3As)2Cl3Os≡N‐RhCl(COD)] (3). The heterometallic complex forms olive green, largely air stable crystals with the monoclinic space group Cc and a = 2316.8(5), b = 1169.3(1), c = 1601.4(2) pm, β = 106.12(1)°, and Z = 4. Rh(I) exhibits a square‐planar coordination with the two π bonds of the COD ligand coordinating in cis position. The osmium nitrido complex is coordinated by a linear nitrido bridge Os≡N‐Rh (Os‐N‐Rh = 176.1(7)°) with distances Os‐N = 168(1) pm and Rh‐N = 186(1) pm.The complex [(Ph3As)2Cl3Os≡N‐IrCl(COD)] (4) is obtained by the reaction of [Ir(μ‐Cl)(COD)]2 with [OsNCl3(AsPh3)2] in CH2Cl2. 4 crystallizes isotypic to 3 in form of olive brown blocks with the space group Cc and a = 2322.1(2), b = 1167.01(6), c = 1603.8(2) pm, β = 105.927(9)°, and Z = 4. The nitrido bridge Os≡N‐Ir is characterized by the bond angle Os‐N‐Ir = 176.2(8)° and distances Os‐N = 171.2(8) pm and Ir‐N = 181.5(8) pm.
Na2[B18Se16]: The First 3D Polymeric Selenoborato‐closo‐dodecaborate
Authors: Hammerschmidt A. , Döch M. , Pütz S. , Krebs B. 
Published: April 2005

AbstractSystematic studies on selenoborates containing a B12 cluster entity and alkali metal cations led to the new crystalline phase Na2[B18Se16] which consists of a icosahedral B12 cluster completely saturated with trigonal‐planar BSe3 units and sodium counter‐ions. The cluster entities are connected to each other via seleno‐ and perselenobridges. Thus a three‐dimensional network results with [(B18Se12Se6/2)n]2−‐ and [(B18Se15Se6/2)n]2− anions in a ratio of 2:1. The new chalcogenoborate was prepared in a solid state reaction from sodium selenide, amorphous boron and selenium in evacuated carbon coated silica tubes at a temperature of 850 °C. Na2[B18Se16] crystallizes in the trigonal space group ${\rm P}{\bar 3}$ (no. 147) with a = 17.021(1) Å, c = 8.903(1) Å and Z = 3.