bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selection of a Pentameric Host in the Host–Guest Complexes {[{[P(μ‐NtBu)]2(μ‐NH)}5]⋅I}−[Li(thf)4]+ and [{[P(μ‐NtBu)]2(μ‐NH)}5]⋅HBr⋅THF
Authors: García Felipe , Goodman Jonathan M. , Kowenicki Richard A. , Kuzu Istemi , McPartlin Mary , Silva María A. , Riera Lucía , Woods Anthony D. , Wright Dominic S. 
Published: November 2004

AbstractThe structures of the host–guest complexes {[{[P(μ‐NtBu)]2(μ‐NH)}5]I}−⋅[Li(thf)4]+ [2⋅I{Li(thf)4}] and [{[P(μ‐NtBu)]2(μ‐NH)}5]⋅HBr⋅THF (2⋅HBr⋅THF) show that increased distortion of the framework of the pentameric macrocycle [{[P(μ‐NtBu)]2(μ‐NH)}5] (2) occurs with the larger halide ions. Theoretical studies show that the thermodynamic stabilities of the model host–guest anions [2⋅X]− (X=Cl, Br, I) are in the order Cl−≈Br−>I−, that is, the reverse of the templating trend observed experimentally. These studies support the view that the selection of the pentamer 2 over the tetramer [{[P(μ‐NtBu)]2(μ‐NH)}4] (1) is kinetically controlled, a conclusion which is also consistent with the previous observation that the frameworks of 1 and 2 are not in dynamic equilibrium with each other.
Microwave‐Assisted Synthesis of Metallic Nanostructures in Solution
Authors: Tsuji Masaharu , Hashimoto Masayuki , Nishizawa Yuki , Kubokawa Masatoshi , Tsuji Takeshi 
Published: November 2004

AbstractMicrowave (MW) rapid heating has received considerable attention as a new promising method for the one‐pot synthesis of metallic nanostructures in solutions. In this concept, advantageous application of this method has been demonstrated by using some typical examples for the preparation of Ag, Au, Pt, and AuPd nanostructures. Not only spherical nanoparticles, but also single crystalline polygonal plates, sheets, rods, wires, tubes, and dendrites were prepared within a few minutes under MW heating. Morphologies and sizes of nanostructures could be controlled by changing various experimental parameters, such as the concentration of metallic salt and surfactant polymer, the chain length of the surfactant polymer, the solvent, and the reaction temperature. In general, nanostructures with smaller sizes, narrower size distributions, and a higher degree of crystallization were obtained under MW heating than those in conventional oil‐bath heating. The origin of these characteristic features under MW irradiation is discussed in terms of thermal and non‐thermal effects under MW irradiation.
Isotope Exchange in Ionised CO2/CO Mixtures: The Role of Asymmetrical C2O3+ Ions
Authors: de Petris Giulia , Cartoni Antonella , Rosi Marzio , Troiani Anna , Angelini Giancarlo , Ursini Ornella 
Published: November 2004

AbstractA hitherto unknown, atmospherically relevant, isotope‐exchange reaction was studied in ionised gaseous mixtures containing carbon dioxide and monoxide. The mechanism of the O exchange, proceeding over a double‐minimum potential‐energy surface, was positively established by mass spectrometric and theoretical methods that also allowed the identification and characterisation of the C2O3+ intermediate. The increase of internal energy displaces the observed reactivity towards an endothermic reaction path that involves only CO2 and represents an indirect route to the dissociation of carbon dioxide.
Molybdenum Phosphide as an o‐Propylaniline Hydrodenitrogenation Catalyst: A First Principles Study
Authors: Milman Victor , Winkler Björn , Gomperts Roberto 
Published: November 2004

AbstractMoP has been shown experimentally to be an active catalyst in the hydrodenitrogenation of o‐propylaniline. We investigate the structure and the energetics of the o‐propylaniline adsorption on the Mo‐terminated MoP(001) surface. Detailed information on the structure of the free MoP(001) surface and on the structure and adsorption energy of o‐propylaniline on MoP(001) is obtained by using density functional theory. The transition state, reaction path, and the energy barrier are reported for one of the branches of the HDN reaction network that leads to the formation of propylbenzene by hydrogenolysis of the CN bond.
Edge‐Bridging and Face‐Capping Coordination of Alkenyl Ligands in Triruthenium Carbonyl Cluster Complexes Derived from Hydrazines: Synthetic, Structural, Theoretical, and Kinetic Studies
Authors: Cabeza Javier A. , del Río Ignacio , Fernández‐Colinas José M. , García‐Granda Santiago , Martínez‐Méndez Lorena , Pérez‐Carreño Enrique 
Published: November 2004

AbstractThe reactions of the triruthenium cluster complex [Ru3(μ‐H)(μ3‐η2‐HNNMe2)(CO)9] (1; H2NNMe2=1,1‐dimethylhydrazine) with alkynes (PhCCPh, HCCH, MeO2CCCCO2Me, PhCCH, MeO2CCCH, HOMe2CCCH, 2‐pyCCH) give trinuclear complexes containing edge‐bridging and/or face‐capping alkenyl ligands. Whereas the edge‐bridged products are closed triangular species (three RuRu bonds), the face‐capped products are open derivatives (two RuRu bonds). For terminal alkynes, products containing gem (RCCH2) and/or trans (RHCCH) alkenyl ligands have been identified in both edge‐bridging and face‐capping positions, except for the complex [Ru3(μ3‐η2‐HNNMe2)(μ3‐η3‐HCCH‐2‐py)(μ‐CO)(CO)7], which has the two alkenyl H atoms in a cis arrangement. Under comparable reaction conditions (1:1 molar ratio, THF at reflux, time required for the consumption of complex 1), some reactions give a single product, but most give mixtures of isomers (not all the possible ones), which were separated. To determine the effect of the hydrazido ligand, the reactions of [Ru3(μ‐H)(μ3‐η2‐MeNNHMe)(CO)9] (2; HMeNNHMe=1,2‐dimethylhydrazine) with PhCCPh, PhCCH, and HCCH were also studied. For edge‐bridged alkenyl complexes, the RuRu edge that is spanned by the alkenyl ligand depends on the position of the methyl groups on the hydrazido ligand. For face‐capped alkenyl complexes, the relative orientation of the hydrazido and alkenyl ligands also depends on the position of the methyl groups on the hydrazido ligand. A kinetic analysis of the reaction of 1 with PhCCPh revealed that the reaction follows an associative mechanism, which implies that incorporation of the alkyne in the cluster is rate‐limiting and precedes the release of a CO ligand. X‐ray diffraction, IR and NMR spectroscopy, and calculations of minimum‐energy structures by DFT methods were used to characterize the products. A comparison of the absolute energies of isomeric compounds (obtained by DFT calculations) helped rationalize the experimental results.
Preparation and Redox Properties of N,N,N‐1,3,5‐Trialkylated Flavin Derivatives and Their Activity as Redox Catalysts
Authors: Lindén Auri A. , Hermanns Nina , Ott Sascha , Krüger Lars , Bäckvall Jan‐E. 
Published: November 2004

AbstractEight different flavin derivatives have been synthesized and the electronic effects of substituents in various positions on the flavin redox chemistry were investigated. The redox potentials of the flavins, determined by cyclic voltammetry, correlated with their efficiency as catalysts in the H2O2 oxidation of methyl p‐tolyl sulfide. Introduction of electron‐withdrawing groups increased the stability of the reduced catalyst precursor.
Novel Formulations of Vitamins and Insulin by Nanoengineering of Polyelectrolyte Multilayers around Microcrystals
Authors: Dai Zhifei , Heilig Anne , Zastrow Heidi , Donath Edwin , Möhwald Helmuth 
Published: November 2004

AbstractMicrocapsules loaded with vitamin K3 (VK3), biotin, or insulin were prepared by using a novel coating technology based on the layer‐by‐layer (LbL) deposition of oppositely charged polyelectrolytes onto microcrystal templates. This produced multilayered, polymeric shells of varying thickness around the crystalline cores. Dissolution of the core material (VK3 with ethanol, biotin with basic solution, and insulin with acidic solution), resulted in its release through the shells. Microelectrophoresis was employed to monitor the microcrystal coating process; confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) were used to verify multilayer coating and the formation of hollow polymer shells following removal of the microcrystal templates. The release rates of both VK3 and insulin decreased as the wall thickness (the number of polyelectrolyte layers deposited onto the microcrystal cores), increased. The release time could be varied by a factor of more than ten, depending on the number of polyelectrolyte layers applied. Following the addition of 70 mass % ethanol, the solubility of VK3 increased by as much as 170‐fold, resulting in an increased rate of VK3 release. By selecting appropriate polymer materials for the shells, and by controlling the number of polyelectrolyte layers applied, shells of various thickness, stiffness, aqueous solubility, dispersibility, biocompatibility, and permeability can be constructed.
A Simple Hydrothermal Route to Large‐Scale Synthesis of Uniform Silver Nanowires
Authors: Wang Zhenghua , Liu Jianwei , Chen Xiangying , Wan Junxi , Qian Yitai 
Published: November 2004

AbstractThis paper describes the preparation of uniform silver nanowires by reducing freshly prepared silver chloride with glucose at 180 °C for 18 hours in the absence of any surfactants or polymers. Scanning electron microscopy studies indicated that the silver nanowires are about 100 nm in diameter and up to 500 μm in length. High‐resolution transmission electron microscopy analyses showed that the silver nanowires grow perpendicularly to the Ag(200) plane. The silver nanowires are believed to grow through a solid–solution–solid process. Some influential factors on the growth of silver nanowires are also discussed.
α1‐Acid glycoprotein fucosylation as a marker of carcinoma progression and prognosis
Authors: Hashimoto Shinji , Asao Takayuki , Takahashi Junko , Yagihashi Yuko , Nishimura Toyo , Saniabadi Abby R. , Poland Dennis C. W. , van Dijk Willem , Kuwano Hiroyuki , Kochibe Naohisa , Yazawa Shin 
Published: November 2004

AbstractBACKGROUNDSerum α1‐acid glycoprotein (AGP), an acute‐phase protein secreted by the liver, carries α(1,3)‐fucosylated structures on its 5 highly branched, N‐linked sugar chains.METHODSSerum AGP levels in patients with various types of malignancies (n = 214 patients) were measured using an enzyme‐linked immunosorbent assay with anti‐AGP antibody. To investigate glycoforms that differed in their degree of branching and extent of fucosylation, serum AGP samples were analyzed by crossed affinoimmunoelectrophoresis (CAIE) with concanavalin A, and Aleuria aurantia lectin (AAL), and anti‐AGP antibody.RESULTSA significant difference (P < 0.001) in serum AGP levels was observed in preoperative patients compared with levels in the healthy control group, but the levels in individual patients did not reflect their clinical status. Conversely, it was found not only that the patterns of AGP glycoforms differed widely in the patient group compared with the healthy control group, but they also changed depending on each patient's clinical status. Furthermore, AGP glycoforms seemed to be appropriate markers of disease progression and prognosis according to follow‐up studies of 45 patients during prolonged preoperative and postoperative periods.CONCLUSIONSPatients with advanced malignancies who had AGP glycoforms that contained highly fucosylated triantennary and tetraantennary sugar chains for long periods after surgery were likely to have a poor prognosis. However, patients who had AGP glycoforms without such changes were expected to have a good prognosis. Cancer 2004. © 2004 American Cancer Society.
Longitudinal study of smoking patterns in relation to the development of smoking‐related secondary primary tumors in patients with upper aerodigestive tract malignancies
Authors: Do Kim‐Anh , Johnson Marcella M. , Lee J. Jack , Wu Xi Feng , Dong Qiong , Hong Waun K. , Khuri Fadlo R. , Spitz Margaret R. 
Published: November 2004

AbstractBACKGROUNDThe authors set out to assess the correlation between smoking‐related second primary tumor (SPT) development and cigarette smoking habits after diagnosis and definitive treatment in patients with early‐stage head and neck squamous cell carcinoma who were enrolled in a placebo‐controlled randomized chemoprevention trial of 13‐cis‐retinoic acid.METHODSLongitudinal data collected for 10 years after the index diagnosis are presented for 1190 patients. Cox proportional hazards regression models were used to examine the effects of changes in smoking behavior on smoking‐related SPT development.RESULTSOne‐third of all patients who quit smoking within 12 months before randomization experienced recurrence, compared with 6.9% and 10.4% of all never‐smokers and former smokers, respectively. Approximately 16% of all current smokers stopped smoking, and nearly 22% of current smokers developed SPTs, compared with 14.5%, 13.2%, and 8.8% of all recent smokers, former smokers, and never‐smokers, respectively. The probability of developing a smoking‐related SPT was highest among patients who were current smokers at randomization. These patients, regardless of whether they ceased smoking during follow‐up, were nearly three times more likely than patients who had never smoked to develop a smoking‐related SPT. In contrast, former smokers and recent quitters who continued to abstain from smoking during follow‐up were approximately 1.5 times more likely to develop an SPT compared with patients who had never smoked.CONCLUSIONSPatients who continue to smoke after the successful treatment of their index head and neck malignancies have a substantially higher risk of developing smoking‐related SPTs. Cancer 2004. © 2004 American Cancer Society.
Heterogeneous cell response to topotecan in a CFSE‐based proliferation test
Authors: Matera Giada , Lupi Monica , Ubezio Paolo 
Published: November 2004

AbstractBackgroundCarboxyfluorescein diacetate succinimidyl ester (CFSE) is currently used to investigate migration and proliferation of hemopoietic cells. In principle, CFSE is retained by the cells and is shared by the daughter cells at each division, resulting in multimodal flow cytometric CFSE histograms, with each cell generation clustering around half the fluorescence intensity of the previous one. However, intercell variability of CFSE loading results in overlapping peaks, thereby limiting its use with cancer cell lines.MethodsWe used IGROV1 ovarian cancer cells loaded with CFSE at the time of seeding; 24 h later cells were treated with an anticancer drug (topotecan). Potential pitfalls of the analysis were examined, and a procedure of evaluation of CFSE efflux was applied to fix the peak positions with good approximation in advance. Histograms were fitted by a series of gaussians, with each representing cells in a given generation.ResultsEffects of topotecan on IGROV1 cells were analyzed in terms of the time course of the percentage of cells that remained undivided or entered the second, third, and subsequent division cycles. A simple algorithm, which combined flow cytometric data with the absolute cell number independently measured by Coulter counter, provided an estimate of the 96‐h outcome of the starting cell population by quantifying cells that remained undivided, those able to divide at least once, or those that had died.ConclusionsWe assessed experimental and data analytic procedures for a CFSE‐based measurement of antiproliferative activity of drugs in cancer cell lines. A quantitative level was achievable but required a strict procedure for control of the experimental data, which was not straightforward. © 2004 Wiley‐Liss, Inc.
Caspr reveals an aggregation of nodes and flanking node free zones at the rat trigeminal sensory root and dorsal root entry zones
Authors: Henry Michael A. , Rzasa Rachael S. , Beeler Joshua J. , Levinson S. Rock 
Published: November 2004

AbstractThe sensory root entry zone demarcates the transition from the peripheral nervous system (PNS) to the central nervous system (CNS). In this study, we describe the organization of nodes of Ranvier at the trigeminal sensory and dorsal root entry zones of the rat. Caspr immunoreactivity (IR) was used to identify the paranodal region of nodes of Ranvier, while L‐MAG‐IR was used to identify CNS oligodendrocytes. Immunofluorescence confocal microscopy revealed a dense aggregation of nodes precisely at the PNS to CNS transition with prominent node‐depleted zones on either side, while L‐MAG‐IR was confined to ensheathing fibers on the central side of nodes located in this dense band and identified these as transitional nodes. Morphometric analysis of the PNS and CNS sides of the trigeminal and the PNS side of the dorsal root entry zones confirmed the presence of virtually node‐free domains flanking the transitional zone. Further, the reappearance of nodes on the far side of the node‐free zones strongly correlated with nodal diameter, with small nodes reappearing first. These findings suggest that the PNS/CNS transition may represent the initial site of myelination of the primary afferent axon within this area. © 2004 Wiley‐Liss, Inc.
Parallelization of MRCI based on hole‐particle symmetry
Authors: Suo Bing , Zhai Gaohong , Wang Yubin , Wen Zhenyi , Hu Xiangqian , Li Lemin 
Published: November 2004

AbstractThe parallel implementation of multireference configuration interaction program based on the hole‐particle symmetry is described. The platform to implement the parallelization is an Intel‐Architectural cluster consisting of 12 nodes, each of which is equipped with two 2.4‐G XEON processors, 3‐GB memory, and 36‐GB disk, and are connected by a Gigabit Ethernet Switch. The dependence of speedup on molecular symmetries and task granularities is discussed. Test calculations show that the scaling with the number of nodes is about 1.9 (for C1 and Cs), 1.65 (for C2v), and 1.55 (for D2h) when the number of nodes is doubled. The largest calculation performed on this cluster involves 5.6 × 108 CSFs. © 2004 Wiley Periodicals, Inc. J Comput Chem 26: 88–96, 2005
Solid‐phase microextraction gas chromatography‐mass spectrometry determination of monoterpenes in honey
Authors: Peña Rosa M. , Barciela Julia , Herrero Carlos , García‐Martín Sagrario 
Published: November 2004

AbstractSolid‐phase microextraction (SPME) using a 100 μm poly(dimethylsiloxane) (PDMS) fiber, followed by gas chromatography (GC‐MS) determination, has been applied to the analysis of some monoterpenoids in honey. The extraction was performed by direct immersion of the fiber using a sampling period of 15 min with constant magnetic stirring (1100 rpm) and an extraction temperature of 20°C. A 7 mL sample volume of an aqueous solution of honey with 25% of NaCl was placed in 15 mL glass vial fitted with screw cap and PTFE/silicone septum. Desorption was performed directly in the gas chromatograph injector port during 5 min at 250°C using the splitless mode. The method is sensitive with detection limits between 11 and 25 μg L–1, precise with coefficients of variation in the range 1.28 and 3.71%, and linear over more than one order of magnitude. The related conditions were used for honey sample analyses with recoveries between 71.8 and 90.9%. SPME remains an attractive alternative technique due to its rapidity and because it is a solvent free extraction method.
Liquid‐phase microextraction utilising plant oils as intermediate extraction medium – Towards elimination of synthetic organic solvents in sample preparation
Authors: Pedersen‐Bjergaard Stig , Rasmussen Knut Einar 
Published: November 2004

AbstractHollow fibre based liquid‐phase microextraction (LPME) using fatty oils and essential oils as the organic phase was evaluated to develop sample preparation technology eliminating the use of hazardous organic solvents. Basic drugs were extracted from different aqueous samples (0.2 to 1 mL) through approximately 15 μL of either almond oil, arachis oil, olive oil, soy‐bean oil, anise oil, fennel oil, lavender oil, or peppermint oil (organic phase) immobilised within the pores of a polypropylene hollow fibre and into 20 μL of 10 mM HCOOH (acceptor phase) present inside the lumen of the hollow fibre. The extraction performance of the essential oils was comparable with the solvents normally used in LPME (dihexyl ether, n‐octanol, and dodecyl acetate) in terms of extraction recovery and extraction speed. Whereas all essential oils tested were compatible with human urine, only anise oil was successful for plasma. The fatty oils provided lower recoveries than the essential oils due to higher viscosity, but all the fatty oils were compatible both with urine and plasma samples. In spite of the multi‐component nature of the oils tested, they were not found to seriously contaminate the acceptor phases during extraction. In conclusion, fatty oils and essential oils may serve as alternative organic phase in LPME, eliminating the use of hazardous organic solvents.
Thymidylate synthase, thymidine phosphorylase, dihydropyrimidine dehydrogenase expression, and histological tumour regression after 5‐FU‐based neo‐adjuvant chemoradiotherapy in rectal cancer
Authors: Jakob Christiane , Aust Daniela E , Meyer Wolfdietrich , Baretton Gustavo B , Schwabe Wolfgang , Häusler Peter , Becker Heinz , Liersch Torsten 
Published: November 2004

AbstractPre‐operative 5‐fluorouracil (5‐FU)‐based chemoradiotherapy in locally advanced rectal cancer (UICC‐II/III) may significantly reduce local tumour mass. Response to pre‐operative treatment, however, varies significantly. Thymidylate synthase (TS), thymidine phosphorylase (TP), and dihydropyrimidine dehydrogenase (DPD) are thought to be important predictors for the efficiency of 5‐FU‐based treatment. The aim of this study was to determine the correlation between TS‐, TP‐, and DPD‐gene expression and the response to 5‐FU‐based long‐term pre‐operative chemoradiotherapy assessed by histopathological tumour regression. Additionally, the predictive value of intra‐tumoural TS‐, TP‐, and DPD‐gene expression in pre‐operative rectal tumour biopsies was assessed by correlation with the histopathological regression grade. Formalin‐fixed, paraffin wax‐embedded pre‐operative biopsies (n = 14) and surgical resection specimens (n = 40) from patients with rectal carcinoma (clinical UICC stage II/III) receiving neo‐adjuvant 5‐FU‐based chemoradiotherapy were studied for TS‐, TP‐, and DPD‐gene expression by quantitative TaqMan real‐time PCR after laser microdissection. Results were compared with standardized histopathological tumour regression analysis. There was a significant association between low TS‐gene expression in pre‐operative tumour biopsies and tumour response (p = 0.02). TS‐ and TP‐gene expression was significantly lower in resection specimens of responders than of non‐responders (p = 0.02) when microdissection was used. Statistical significance was even higher when TS and TP were combined (p = 0.0001). For the DPD gene, no significance was found at all. In conclusion, this study shows that TS gene expression in a pretreatment biopsy predicts the response of local rectal cancer to neo‐adjuvant 5‐FU‐based chemoradiotherapy in a high percentage. Moreover, intra‐tumoural TS‐ and TP‐gene expression in surgical rectal specimens after neo‐adjuvant chemoradiotherapy correlates significantly with histopathological tumour regression when microdissection is applied. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.