bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chiral derivatives of 2‐(1‐naphthyl)‐2‐phenylacetic acid
Authors: Vávra Jan , Vodička Petr , Streinz Ludvík , Buděšínský Miloš , Koutek Bohumír , Ondráček Jan , Císařová Ivana 
Published: September 2004

AbstractThe spectral properties of diastereomeric esters and amides (1b–20b), derived from optically pure 2‐(1‐naphthyl)‐2‐phenylacetic acids (1‐NPA), were systematically investigated. It was found that all compounds prepared exhibit the NMR spectral nonequivalence (Δδ) with regular sign distribution of particular groups according to the predicted model. Further, the analysis of data revealed that the phenyl ring is responsible for a shielding effect (upfield shift) instead of a naphthyl one. This conclusion is supported by the crystallographic analysis showing the almost ap‐arrangement of the acid methine hydrogen atom and carbonyl group. In this arrangement, the phenyl ring faces toward the ester part of the molecule while the naphthyl one is orthogonal to the phenyl plane. Therefore, the mutual position of phenyl and alkyl groups with respect to the central molecule co‐planarity thus determines the chemical shifts of the alcohol/amine substituents. The relative magnitude of the Δδ corresponds to those of Mosher's derivatives. Chirality 16:652–660, 2004. © 2004 Wiley‐Liss, Inc.
Chiral effect on a self‐assembling bicopper complex
Authors: Liu Weihong , Guenet Jean‐Michel , Green Mark M. 
Published: September 2004

AbstractA bicopper complex was prepared with chiral ligands. The self‐assembly of the complex in trans‐decalin differed greatly for the racemic and nonracemic ligands. With the latter the resulting gel formed at a lower concentration and exhibited a higher thermal transition temperature. A large optical activity was found in the nonracemic bicopper complex, which was used to probe the process of filament formation, i.e., the aggregation‐dissociation process. The material with nonracemic ligands may form a longer nanoscopic filament. Chirality 16:661–664, 2004. © 2004 Wiley‐Liss, Inc.
Pulmonary adenocarcinoma is associated with poor long‐term survival after surgical resection
Authors: Ghosh Sudip , Ahmed Kamran , Hopkinson David N. , Vaughan Roger 
Published: September 2004

AbstractBACKGROUNDThe significance of allogeneic blood transfusion in the prognosis of patients with nonsmall lung carcinoma (NSCLC) remains controversial. Reports have suggested that patients with adenocarcinoma have a worse prognosis from cancer than patients with squamous cell carcinoma (SCC), but this evidence is lacking in NSCLC. The objective of the current study was to elucidate the correlation between perioperative allogeneic blood transfusion and the prognosis in patients with adenocarcinoma and SCC.METHODSThe study group comprised 329 consecutive patients (172 men and 157 women) with a mean age of 67 years who underwent lung resection between 1996 and 2003 in 1 unit. The clinicopathologic and survival data were compared between 62 patients (42.7%) with adenocarcinoma and 58 patients (48.3%) with SCC who received a perioperative blood transfusion and 83 patients (57.3 %) with adenocarcinoma and 126 patients (61.3%) with SCC who did not.RESULTSThe overall surgical mortality rate was 3.9% (13 deaths). The median surgical blood loss was 380 mL (range, 125–4500 mL). The mean blood transfusion received was 1.9 U (range, 0–8 U). The overall actuarial 1, 3, and 5‐year survival rates in the adenocarcinoma and SCC groups were 82.3%, 49.6%, and 19.4% and 87.9%, 71.7%, and 32.7%, respectively (P = 0.021). Multivariate analysis demonstrated that the factors that appeared to be independent prognostic factors in both groups were T‐classification (P < 0.001), lymph node metastasis (P < 0.001), and postoperative complications (P = 0.029). Perioperative blood transfusion was not an independent prognostic indicator in either group.CONCLUSIONSThe current study demonstrated that long‐term survival in patients with adenocarcinoma of the lung was significantly worse compared with patients with SCC, but was independent of allogeneic perioperative blood transfusion. The results reaffirmed the importance of tumor invasion and lymph node involvement in the overall poor prognosis of these patients. Cancer 2004. © 2004 American Cancer Society.
Histone H2AX phosphorylation induced by selective photolysis of BrdU‐labeled DNA with UV light: Relation to cell cycle phase
Authors: Huang Xuan , A. King Malcolm , Halicka H. Dorota , Traganos Frank , Okafuji Masaki , Darzynkiewicz Zbigniew 
Published: September 2004

AbstractBackgroundThe induction of DNA double‐strand breaks (DSBs) in chromatin triggers histone H2AX phosphorylation (on Ser‐139) by ATM‐, ATR‐, or DNA‐dependent protein kinases (DNA‐PK). Phosphorylated H2AX, denoted as γH2AX, can be detected immunocytochemically using an antibody that is specific to the Ser‐139–phosphorylated epitope. We previously reported that the induction DSBs by DNA topoisomerase I or II inhibitors can be monitored in individual cells by measuring γH2AX immunofluorescence (IF) by cytometry. The present study explored whether the detection of γH2AX IF can serve as a marker of the presence of the DNA precursor bromodeoxyuridine (BrdU) that is incorporated into DNA.MethodsHeLa cells growing on microscope slides were incubated with BrdU for 1 h, rinsed free of the precursor, and incubated for different periods for up to 12 h. The cells were then briefly incubated with Hoechst 33342 (to sensitize BrdU‐labeled DNA to ultraviolet [UV] light), irradiated with 300 nm UV light to photolyze BrdU‐labeled DNA, transferred back into culture for an additional hour, and fixed. Cells were concurrently immunostained for γH2AX (Alexa Fluor 633) and cyclin A (fluorescein isothiocyanate); their DNA was counterstained with 4,6‐diamidino‐2‐phenylindole. The intensities of cellular far red (γH2AX), green (cyclin A), and blue (DNA) fluorescences were measured by laser scanning cytometry.ResultsAfter a 1‐h pulse of BrdU followed by exposure to UV, nearly all cells with S‐phase DNA content had many‐fold higher γH2AX IF than G1 or G2/M cells. The nonirradiated cells had minimal (“programmed”) expression of γH2AX, whereas the irradiated cells incubated without BrdU had uniformly elevated levels of γH2AX IF independent of the cell cycle phase. Pulse‐chase experiments showed that the cohort of BrdU‐labeled (γH2AX‐positive) cells progressed through G2/M and into G1 phase after 8 and 12 h of growth in BrdU‐free medium, respectively. Bivariate analysis of γH2AX versus cyclin A expression for the gated S‐phase cells showed a correlation between these variables, suggesting that the rate of BrdU incorporation (DNA replication) correlates with expression of cyclin A.ConclusionsPhotolysis of BrdU‐labeled DNA induces DSBs and leads to H2AX phosphorylation. Detection of γH2AX IF indicates the presence of the incorporated BrdU, is compatible with concurrent detection of other intracellular antigens, and can be used to demonstrate cell cycle kinetics. © 2004 Wiley‐Liss, Inc.
Identification of Chiral cis‐ and trans‐2‐Stannyloxazolidines by Their NMR Spectra and Solid‐State Structures
Authors: Cintrat Jean‐Christophe , Léat‐Crest Véronique , Parrain Jean‐Luc , Grognec Erwan Le , Beaudet Isabelle , Toupet Loïc , Quintard Jean‐Paul 
Published: September 2004

AbstractThe assignment of cis and trans configurations in N‐protected 4‐substituted 2‐tributylstannyl‐1,3‐oxazolidines by NMR has been achieved through the use of extrapolations of Karplus−Kitching‐type relationships for 3J(119Sn−C−Z−13C) to establish the shape of the oxazolidine ring. Examination of 3J(H,H) allowed the determination of torsion angles for the substituents on C4 and C5, discrimination being completed by comparison of the H2 chemical shifts, together with the 2J(Sn−C−H2) values. The validity of the method was subsequently corroborated by comparison of the results obtained for the liquid phase with those obtained from radiocrystallographic structures of triphenylstannyl analogues or DFT calculations on trimethylstannyl analogues. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The Conformational Behavior of Novel Glycosidase Inhibitors with Substituted Azepan Structures: An NMR and Modeling Study
Authors: Martínez‐Mayorga Karina , Medina‐Franco José L. , Mari Silvia , Cañada F. Javier , Rodríguez‐García Eliazar , Vogel Pierre , Li Hongqing , Blériot Yves , Sinaÿ Pierre , Jiménez‐Barbero Jesús 
Published: September 2004

AbstractThe conformational analysis of a series of configurational isomers of 2‐(hydroxymethyl)azepan‐3,4,5,6‐tetrols 1−4 has been carried out. 1H NMR spectroscopic data, especially vicinal J couplings and nuclear Overhauser enhancements (NOE), assisted by molecular mechanics, molecular dynamics and Monte Carlo calculations, have been used. A fairly good agreement between experimental and calculated data has been found. The different isomers exist in a conformational equilibrium between two chair‐like structures. TR‐NOE experiments have also allowed us to demonstrate that the bound conformation of compound 2 to the β‐glucosidase from almonds is the major one of this compound present in solution. Finally, molecular docking of the different conformations of these compounds in the binding site of three different enzymes has been performed in order to try to rationalize the observed inhibition of these molecules. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis of Functionalized 1‐Substituted Alkenylsilanols and Establishment of Conditions for Their Palladium‐Catalyzed Cross‐Coupling Reactions To Afford 1‐Substituted Styrene Derivatives
Authors: Ghosh Sunil K. , Singh Rekha , Singh Gobind C. 
Published: September 2004

AbstractAn efficient method for the quantitative conversion of 1‐substituted alkenyl(phenyl)silanes into the corresponding alkenylsilanols has been developed and used in their palladium(0)‐catalyzed, tetrabutylammonium fluoride‐promoted cross‐coupling reaction with aryl iodides. Copper(I) chloride modulated the reactivity of TBAF in such a way that it virtually eliminated the protiodesilylation of alkenylsilanols, thus favoring the formation of ipso‐coupled products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
1,3‐Dipolar Cycloaddition Reactions with 1,2,3‐Triazinium Ylides
Authors: Mättner Michael , Neunhoeffer Hans 
Published: September 2004

Abstract1,3‐Dipolar cycloadditions were carried out with 1,2,3‐triazinium 2‐dicyanomethylylides 4 and deprotonated 2‐ethyl‐1,2,3‐triazinium salts 2. Pyrazolo[2,1‐a]‐ and pyrazolo[1,2‐b][1,2,3]triazines 5 and 9 were synthesized, representing new heterocyclic systems. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A Convenient New Synthesis of 3‐Substituted β‐Lactams Formally Derived from 1‐(Aminomethyl)cyclopropanecarboxylic Acids
Authors: Zanobini Alessandra , Gensini Martina , Magull Jörg , Vidović Denis , Kozhushkov Sergei I. , Brandi Alberto , de Meijere Armin 
Published: September 2004

Abstract1,3‐Dipolar cycloaddition of N‐benzyl‐C‐(methoxycarbonyl)nitrone (3a), N‐benzyl‐C‐phenylnitrone (3b), N‐benzyl‐C‐cyanonitrone (3c), N‐(p‐methoxybenzyl)‐C‐cyanonitrone (3d), N‐phenyl‐ (3e) and N‐(2‐pyridyl)‐C‐methylnitrones (3f) to bicyclopropylidene (2) gave the corresponding cycloadducts 5a−f in 100, 95, 94, 100, 93 and 71% yields, respectively. Treatment of these bisspirocyclopropanated isoxazolidines with trifluoroacetic acid in acetonitrile furnished the corresponding 3‐spirocyclopropanated β‐lactams 7a−f in 78, 75, 75, 94, 96 and 96% yields, respectively. The structures of the cycloadduct 5b and of the β‐lactam 9a were proved by X‐ray crystal structure analyses. Thus, this new method furnishes compounds with a 5‐azaspiro[2.3]hexan‐4‐one skeleton in 68−94% overall yield in two simple steps. β‐Lactams 7a, 7b, and 7d were converted into their N‐acyl derivatives 9a, 9b, 9d and 11 in 44, 28, 39 and 78% yields, respectively. Heating of the β‐lactams 9b and 11 with tert‐butyl glycinate (12) or with tert‐butyl (S)‐phenylalaninate (14) in DMF led to ring‐opening of the β‐lactam moiety to give β‐dipeptides 15, 16 and 17 in 61, 84 and 79% yields, respectively, while β‐lactam 9a gave the amide 13 (51% yield). β‐Lactams 7e and 7f turned out not to be transformable into such peptide products (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Determination of the Boron/Lead Ratio in Ceramic Materials Based on Electrochemical Quartz Crystal Microbalance
Authors: Doménech‐Carbó A. , Sánchez‐Ramos S. , Yusá‐Marco D. J. , Moya‐Moreno M. , Gimeno‐Adelantado J. V. , Bosch‐Reig F. 
Published: September 2004

AbstractA method for quantitatively determining the relationship boron/lead in ceramic materials is presented. It is based on the attachment of microsamples of ceramic frits to an electrochemical quartz crystal microbalance (EQCM). After a reductive deposition step in the −0.25 to −0.85 V (vs. AgCl/Ag) potential range, well‐defined stripping peaks are recorded in 0.10 M NaCl plus 0.10 M mannitol. The deposition of boron and lead from suspensions of solid materials, and its subsequent oxidative dissolution can be monitorized at the EQCM. The quotient between the maximum mass gain and the corresponding charge passed enables for a direct quantitation of the boron/lead molar ratio in ceramic materials. Addition methods based on the EQCM examination of i) sample plus lead white (2PbCO3.Pb(OH)2) and ii) sample plus Li2B4O7 mixtures are also presented. Results for boron‐containing ceramic frits are in excellent agreement with those obtained by reference methods.
Voltammetric Determination of Antibacterial Nitro‐Compounds at Activated Carbon Fibre Microelectrodes
Authors: Guzmán A. , Agüí L. , Pedrero M. , Yáñez‐Sedeño P. , Pingarrón J. M. 
Published: September 2004

AbstractThe electrochemical behavior of the nitrofuran antibiotics nitrofurantoin (NFA) and nitrofurazone (NFZ), as well as the related nitroimidazole drug, metronidazole (MNZ) at electrochemically activated carbon fibre microelectrodes (CFMEs) is reported. These nitrofurans have been widely used in the form of feed additives for the treatment of gastrointestinal infections in cattle, pigs and poultry. Electrochemical activation of CFMEs by repetitive square‐wave (SW) voltammetric scans between 0.0 and +2.6 V, produced an unexpected high cathodic response from these compounds. This is attributed to the increase of the carbon fibre surface area due to its fracture and the appearance of deep fissures along the main fibre axis. Penetration of the nitroderivative compounds into the micro‐channels of the activated fibres was profited to develop a sensitive and selective method for NFA based on stripping SW voltammetry. The metabolite of NFA, 1‐aminohydantoin (AHD), did not exhibit cathodic response in the potential range between −0.9 and +0.1 V. However, AHD gave a SW oxidation signal at activated CFMEs, with a potential of +0.95 V, which did not appear at non‐activated microelectrodes. Based on this finding, the simultaneous determination of NFA and AHD was performed by amperometry using two activated CFMEs in a parallel configuration connected to a multichannel detector. This methodology was also used to carry out degradation studies of NFA in acidic and basic media under photodegradation or thermal degradation conditions.
Coupled Electron‐Proton Transport in Electropolymerized Methylene Blue and the Influences of Its Protonation Level on the Rate of Electron Exchange with β‐Nicotinamide Adenine Dinucleotide
Authors: Komura T. , Niu G. Y. , Yamaguchi T. , Asano M. , Matsuda A. 
Published: September 2004

AbstractThis paper describes electrochemical characteristics of poly(methylene blue) electrolytically deposited on glassy carbon and examines the electrocatalytic activity of the polymer toward oxidation of the coenzyme NADH. Redox‐active properties of the cationic polyelectrolyte arose from both electron self‐exchange between electroactive sites and a high ionic film‐conductivity. The diffusion coefficient of charge carriers in the film increased with decreasing solution pH, indicating the pH dependence of the electron diffusion coefficient. The electrocatalytic oxidation of NADH at the polymer‐modified electrode proceeded via an intermediate charge‐transfer complex of the reduced polymer with the oxidized coenzyme. The complex dissociated more rapidly into the oxidation products as the reduced polymer protonated. Thus, the rate constant for the cross‐exchange reaction rose with a decrease in pH. For NADH oxidation, the polyelectrolyte exhibited an electrocatalytic activity higher than the monomeric dye because of a stronger oxidizing power of the second oxidized form of the polymer.
Comparison of an Electronic Nose with the Sensory Evaluation of Food Products by “Triangle Test”
Authors: Benedetti Simona , Pompei Carlo , Mannino Saverio 
Published: September 2004

AbstractIn this paper a novel approach for performing discriminative test in food quality control is reported. The method is based on the use of an electronic nose equipped with 10 Metal Oxide Semiconductor Field Effect Transistor (MOSFET) sensors, 12 Metal Oxide Semiconductor (MOS) sensors and one humidity sensor. The pattern of the sensor responses generated by the electronic nose has been used for performing “objective” triangle tests in several food products. The results were compared with the data obtained by using standard methodology (triangle test) of sensory analysis (UNI ISO 4120 Norm). The e‐nose is able to classify correctly all the samples under study, while the sensory panel is able to correctly perform the test only in 50% of the cases. As compared with the sensory test, the electronic nose methodology is simple, rapid and results suggest that it can be useful tool for performing discriminative testing.
Attachment of Amine‐ and Maleimide‐Containing Ferrocene Derivatives onto Self‐Assembled Alkanethiol and Alkanedithiol Monolayers: Voltammetric Evaluation of Cross‐Linking Efficiencies and Surface Coverage of Electroactive Groups
Authors: Wang Yunfeng , Yao Xin , Wang Jianxiu , Zhou Feimeng 
Published: September 2004

AbstractFerrocene derivatives containing primary amines and maleimide groups were attached covalently onto N‐hydrosuccinimidyl (NHS)‐terminated alkanethiol self‐assembled monolayers (SAMs) and SAMs of alkanedithiol. The surface coverage and efficiencies of the two cross‐linking reactions were evaluated with cyclic voltammetry. All the ferrocene derivatives attached onto the alkanethiol or alkanedithiol SAMs exhibit reversible redox waves. The surface coverage of the aminated ferrocene groups was compared to that of N‐hydrosuccinimidyl (NHS)‐terminated alkanethiol SAM. The covalent attachment of β‐ferrocenylethylamine onto a 11,11′‐dithio‐bis(succinimidylundecanoate) SAM yielded an efficiency as high as 63.1%. The cross‐linking efficiency of this reaction was found to increase with the nucleophilicity of the amino groups. SAMs of longer alkyl chains favor the attachment of a greater number of ferrocene derivatives. As for the Michael‐type electrophilic addition between the sulfhydryl groups of the alkanedithiol SAMs and the ferrocenyl maleimide, the cross‐linking efficiencies were found to range from 6.5% to 25.7%, depending on the alkanedithiol chain length. The difference in the efficiencies between the two types of cross‐linking reactions might be partially attributable to the steric hindrance imposed by the SAMs and the relative sizes of the functional groups.
Detecting Both Physical and (Bio‐)Chemical Parameters by Means of ISFET Devices
Authors: Poghossian Arshak , Schöning Michael J. 
Published: September 2004

AbstractA multi‐parameter sensor system for the detection of eight (bio‐)chemical and physical parameters (pH, potassium concentration, penicillin concentration, diffusion coefficient of H+‐ and OH –‐ions, temperature, flow velocity, flow direction and liquid level) is realized by using the same transducer principle. A Ta2O5‐gate ISFET (ion‐sensitive field‐effect transistor) is applied as basic transducer for all kinds of sensors. The multi‐parameter detection is achieved by means of sequentially or simultaneously scheduling of the hybride sensor modules consisting of four ISFET structures and an ion generator in different sensor arrangements and/or different operation modes. Thus, more parameters (eight) can be detected than the number of sensors (four) in the system.
Revisiting the role of Broca's area in sentence processing: Syntactic integration versus syntactic working memory
Authors: Fiebach C.J. , Schlesewsky M. , Lohmann G. , von Cramon D.Y. , Friederici A.D. 
Published: September 2004

AbstractMost previous neuroimaging studies of sentence processing have associated Broca's area with syntactic processing; however, the exact nature of the processes subserved by this brain region is yet not well understood. Although some authors suggest that Brodmann area (BA) 44 of the left inferior frontal gyrus (i.e., Broca's area) is relevant for syntactic integration processes, others claim that it is associated with working memory mechanisms relevant for language processing. To dissociate these two possible functions, the present study investigated hemodynamic responses elicited while participants processed German indirect wh‐questions. Activation increases were observed in left BA 44 together with superior temporal areas and right hemispheric homologues for sentences with noncanonical word order, in which a verb argument was dislocated from its canonical position over a relatively long distance. In these sentences, syntactic working memory load was assumed to be greatest. In contrast, no activation increase was elicited by object–initial as opposed to subject–initial sentences that did not differ with respect to working memory costs but with respect to syntactic integration costs. These data strongly suggest that Broca's area plays a critical role in syntactic working memory during online sentence comprehension. Hum. Brain Mapping 24:79–91, 2005. © 2004 Wiley‐Liss, Inc.
Antitumor activity of the intratumoral injection of fowlpox vectors expressing a triad of costimulatory molecules and granulocyte/macrophage colony stimulating factor in mesothelioma
Authors: Triozzi Pierre L. , Aldrich Wayne , Allen Karen O. , Lima Jose , Shaw Denise R. , Strong Theresa V. 
Published: September 2004

AbstractDeficiency in costimulatory molecule expression has been implicated in the ability of tumors to escape immune effectors. The activity of the intratumoral administration of recombinant fowlpox vectors expressing a triad of costimulatory molecules (rF‐TRICOM) was evaluated in the asbestos‐induced AB12 and AC29 mouse models of mesothelioma. Mesothelioma cell infected with rF‐TRICOM expressed high levels of the costimulatory molecules. Prolongation of survival was observed in mice receiving rF‐TRICOM in AB12 and AC29 intraperitoneal models. Complete tumor regressions were observed in mice receiving intratumoral rF‐TRICOM in the AB12 subcutaneous tumor model. Tumor regressions were associated with the development of serum IgG reactivities to mesothelioma‐associated determinants and specific systemic cytolytic activity, and responding mice were capable of rejecting tumors upon re‐challenge. Antitumor activity was also observed in mice with established AB12 tumor vaccinated with irradiated rF‐TRICOM‐infected AB12 cells. The antitumor activity of intratumoral rF‐TRICOM was superior to that of the intratumoral injection of a fowlpox vector expressing granulocyte‐macrophage colony stimulating factor (rF‐GM‐CSF). AB12 and AC29 tumors were found to produce GM‐CSF and to have substantial macrophage infiltration. Production of GM‐CSF decreased in vivo in tumors injected with rF‐TRICOM. rF‐TRICOM and wild‐type fowlpox inhibited the growth of AB12 and AC29 cells in vitro; less inhibition was observed with rF‐GM‐CSF. These results indicate that the intratumoral injection of rF‐TRICOM has significant activity in mouse models of mesothelioma and can elicit a systemic antitumor immune response. The results also suggest potential limitations to the intratumoral administration of cytokines, such as GM‐CSF, in mesothelioma.