bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics and mechanisms of gas phase elimination of ethyl 1‐piperidine carboxylate, ethyl pipecolinate, and (revisited) ethyl 1‐methyl pipecolinate
Authors: Rosas Felix , Monsalve Angiebelk , Tosta María , Herize Armando , Domínguez Rosa M. , Brusco Doris , Chuchani Gabriel 
Published: April 2005

AbstractThe kinetics of the gas‐phase elimination of the title compounds has been determined in a static reaction system over the temperature range of 340–420°C and pressure range of 45–96 Torr. The reactions proved to be homogeneous, unimolecular, and obey a first‐order rate law. The estimated rate coefficients are represented by the following Arrhenius expressions: Ethyl 1‐piperidine carboxylate

Ethyl pipecolinate

Ethyl 1‐methyl pipecolinate

The first step of decomposition of these esters is the formation of the corresponding carboxylic acids and ethylene. The acid intermediate undergoes a very fast decarboxylation process. The mechanism of this elimination reactions is suggested on the basis of the kinetic and thermodynamic parameters. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 383–389, 2005
Multidentate ligand exchange kinetics: Substitution reaction of polyaminocarboxylatoferrate (III) complex, [FeHPDTA(OH)]2− with 4‐(2‐pyridylazo)resorcinol
Authors: Naik R. M. 
Published: April 2005

AbstractThe kinetic study of ligand substitution reaction of 2‐hydroxy 1,3‐diamino propane N,N′N′‐tetraacetatoiron(III) ([FeHPDTA(OH)]2−) complex with 4‐(2‐pyridylazo)resorcinol (Par) has been followed spectrophotometrically at pH = 9.00 ± 0.02, I = 0.1 M (NaClO4), and temperature = 25.0 ± 0.1°C. The forward and reverse reactions have been studied at 496 nm, the λmax of [Fe(Par)2]− which is identified as the final product of above reaction. The second‐order rate constants for the reaction of [FeHPDTA(OH)]2− with Par were determined in a wide pH range viz. 8.0–11.5. It is observed from pH dependence of reaction that rate of reaction increases initially with pH and then levels off. In the case of reverse reaction between [Fe(Par)2]− and HPDTA4−, the pseudo‐first‐order rate constant does not change with concentration at extremely low concentration of [HPDTA]4− and shows zero‐order dependence in [HPDTA]4−. At relatively higher concentration of [HPDTA]4−, the order of reaction with respect to [HPDTA]4− is found to be 1. An inverse first‐order dependence is also observed with respect to added [Par]2−. The activation parameters were evaluated for forward and reverse reactions, which further supported the proposed mechanistic scheme. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 333–340, 2005
Hydrolytic Degradation of Double Crystalline PPDX‐b‐PCL Diblock Copolymers
Authors: Albuerne Julio , Marquez Leni , Müller Alejandro J. , Raquez Jean‐Marie , Degée Philippe , Dubois Philippe 
Published: April 2005

AbstractSummary: The degradation behavior of the diblock copolymers PPDX‐b‐PCL was studied under in vitro conditions, in samples with high PPDX content. Molded films were immersed in phosphate buffer solution at pH = 7.4 and 37 °C for 9 months. The samples were periodically extracted, dried and evaluated by weighing, SEC, 1H NMR, DSC, and POM. The results point out that an increase in PCL content reduced the weight loss in the diblock copolymers. 1H NMR and DSC analysis showed that degradation occurred almost exclusively in the PPDX block during the first 9 months of hydrolysis. POM results for the diblock copolymer with high PPDX content (77%) indicated the presence of some typical homo‐PPDX spherulites in the 0.8 months degraded sample when no weight loss was detected. This result demonstrated that random chain scission during the early stages of degradation can produce homo‐PPDX chains that cannot be dissolved in the hydrolysis medium because their molecular weight is still too high. It was found that a small increase in PCL content in the diblock copolymers produced a synergistic increase in the PPDX block degradation stability. This is a direct result of the inter‐digitized lamellar morphology present in the copolymers where PCL and PPDX lamellae are alternated within mixed spherulites. In view of its much higher resistance to hydrolysis, the PCL lamellae offer a barrier‐type protection to the PPDX within the copolymer. A schematic morphological model is proposed to explain the observed changes during the different degradation stages encountered by the diblock copolymers.Proposed scheme for the hydrolytic degradation process of PPDX‐b‐PCL diblock copolymers.imageProposed scheme for the hydrolytic degradation process of PPDX‐b‐PCL diblock copolymers.
Tautomerism and 1H, 13C and 15N NMR spectral assignments of some nitro derivatives of malonic acid diamide
Authors: Sebban Muriel , Guillard Jérome , Palmas Pascal , Poullain Didier 
Published: April 2005

AbstractBecause of its reactivity, malonic acid diamide (1) was initially identified as an alternative precursor for the development of a new class of high‐density insensitive energetic materials possessing low sensitivity to thermal decomposition and detonation by impact. Nitration of 1 was studied under different conditions and led to three different tautomeric forms (2–4) of nitromalonic acid diamine. Using stronger oxidation conditions the oxadiazole 5 was generated in one step. We report the full 1H, 13C and 15N NMR structural characterization of these compounds in DMSO together with thermal, infrared, mass spectrometric and x‐ray analysis. Experimental data obtained for 4 are compatible with an enol‐imine form. Our interpretation is consistent with calculated 1H and 13C NMR spectra (ACD). Copyright © 2005 John Wiley & Sons, Ltd.
Concerning the origin of 19F19F NMR COSY and NOESY connections in the spectra of perfluorooctanoic acid, RF‐palmitic acid‐F13 and diethyl perfluorosuberate
Authors: Buchanan Gerald W. , Munteanu Elena , Dawson Brian A. , Hodgson Derek 
Published: April 2005

AbstractA combination of 19F nuclear Overhauser effects (NOE) and molecular mechanics calculations are presented for delineating the spatial origin of the well‐known four‐bond 19F19F COSY connections which are generally observed in the 19F NMR spectra of compounds containing perfluorinated chains. Perfluorooctanoic acid (PFOA), RF‐palmitic acid‐F13 and diethyl perfluorosuberate were used as test cases. Spin–lattice relaxation times (T1) are included and NOESY correlations through three and four bonds occur. Copyright © 2005 John Wiley & Sons, Ltd.
Acid/base Micropatterned Devices for pH‐Dependent Biosensors
Authors: Valsesia Andrea , Manso Silvan Miguel , Ceccone Giacomo , Gilliland Douglas , Colpo Pascal , Rossi François 
Published: April 2005

AbstractSummary: Micropatterned surfaces of poly(acrylic acid) (PAA) and poly(allylamine) (PAL) were prepared by the combination of plasma enhanced chemical vapour deposition (PE‐CVD) and physical masking techniques. The deposition process for both polymers was optimized in order to obtain a good compromise between the stability and the specific chemical functionality of the surface. X‐ray photoelectron spectroscopy, and secondary ion mass spectrometry were used to determine the chemical characteristics of the surfaces. The use of the imaging mode provided a determination of the chemical contrasts at the micrometre scale. The evaluation of the specific interaction forces, acting between the surfaces and the COOH‐functionalized tips, as a function of the pH, was performed by chemical force microscopy. The force‐distance curves provided the basis for a semi‐quantitative calculation of the interaction forces between the tip and the surfaces. The repulsive or attractive nature of the interaction forces is due to the variation in the charge concentration on the surfaces. This allowed the determination of pH‐dependent force maps where the PAA and PAL show a contrast in the adhesion force.Optical image of the investigated area on the micropatterned PAA/PAL surface.magnified imageOptical image of the investigated area on the micropatterned PAA/PAL surface.
Some Important Aspects of Plasma Polymerization
Authors: Yasuda Hirotsugu K. 
Published: April 2005

AbstractSummary: Some important aspects of the processing of plasma polymerization coating, which are not well known or well practiced, are discussed in a brief topical overview. Those aspects are the following: 1) power input parameters for diffuse luminous gas phase polymerization, DC cathodic polymerization, and low pressure cascade arc torch (LPCAT) polymerization, 2) ionization in negative glow versus molecular dissociation in dissociation glow (cathode glow), 3) influence of the deposition plasma on the substrate polymer, 4) types of plasma polymers, 5) importance of the amorphous nature of plasma polymers, 6) chemical reactions in beams versus in the gas phase, and 7) onion‐layered structure of the luminous gas phase and operation scale‐up.Glow discharges of Ar (left) and of an organic molecule (right).magnified imageGlow discharges of Ar (left) and of an organic molecule (right).
8th International Workshop on Plasma‐Based Ion Implantation and Deposition
Authors: Chu Paul K. 
Published: April 2005

AbstractPlasma News: This section contains news of the plasma community all over the world. Articles about, for example, people, projects, and market trends are welcome. Suggestions should be sent to the editorial office of Plasma Processes and Polymers, preferably by E‐mail to plasma@wiley‐vch.de. The editorial office decides which articles will be published.
Response to fire of concrete structures that incorporate FRP
Authors: Bisby Luke A , Green Mark F , Kodur Venkatesh K R 
Published: April 2005

AbstractAfter more than twenty years of research investigating fibre‐reinforced polymers (FRPs) for reinforcing and strengthening concrete structures, FRPs are now widely recognized as useful materials in the ongoing struggle against infrastructure deterioration. However, applications of FRPs in the field have been limited primarily to bridges, where fire is not a primary consideration during design. Because FRP materials are combustible and susceptible to deterioration of mechanical and bond properties at only modestly elevated temperatures, there is legitimate concern that FRP reinforcing and strengthening systems for concrete will perform poorly in fire. This paper presents a review of research conducted to investigate the fire performance of FRP materials for infrastructure applications. Also presented is an overview of an ongoing research program that is currently underway at Queen's University and the National Research Council of Canada (NRC) to investigate the performance in fire of FRP‐strengthened reinforced concrete slabs, beams, and columns. This work has demonstrated that FRP strengthened concrete structures can be protected to provide sufficient fire endurance. Recommendations for future research are provided. Copyright © 2005 John Wiley & Sons, Ltd.
Alpha‐hydroxybutyrate dehydrogenase activity in intrahepatic cholestasis of pregnancy
Authors: Wojcicka J. , Sienko J. , Smolarczyk R. , Romejko E. , Grymowicz M. , Czajkowski K. 
Published: April 2005

AbstractObjectivesIntrahepatic cholestasis of pregnancy (ICP) is associated with increased perinatal mortality and morbidity. Alpha‐hydroxybutyrate dehydrogenase (α‐HBDH) is an enzyme that originates in the cytoplasm of hepatocytes and can be detected in the serum. The aim of this study was to determine the characteristics of α‐HBDH activity in ICP.MethodsThe study included 100 women in their third trimester of pregnancy, 58 of whom had ICP (the study group) and 42 were healthy (the control group); another group, 26 nonpregnant women, was also analyzed to follow changes in α‐HBDH activity during pregnancy. The concentrations or activity of fractionated bilirubin; bile acids; total alkaline phosphatase; alanine and aspartate aminotransferases; total high‐density and low‐density lipoprotein cholesterol; triglycerides; total protein; and α‐HBDH were assessed.ResultsThe activity of serum α‐HBDH is increased during the third trimester of pregnancies complicated by ICP, and it correlates positively with total and direct bilirubin concentration and total alkaline phosphatase activity.ConclusionsAlpha‐hydroxybutyrate dehydrogenase serum activity seems to be another biochemical parameter useful in the assessment of ICP severity.
The Interaction of Human and Physical Capital Accumulation: Evidence from Sub‐Saharan Africa*
Authors: Grier Robin 
Published: April 2005

SummaryIn this paper, a simultaneous model of the evolution of human and physical capital in Sub‐Saharan Africa is estimated. It can be shown that the two types of capital are jointly endogenous, in that increases in human capital significantly raise the per‐worker physical capital stock, and increases in the physical capital significantly raise primary education levels. Unlike the implications of other recent papers, there is no evidence that tropical climates and ethnic diversity have a negative effect on the accumulation of capital in the region.
Analysis of vegetation distribution in Interior Alaska and sensitivity to climate change using a logistic regression approach
Authors: Calef Monika P. , David McGuire A. , Epstein Howard E. , Scott Rupp T. , Shugart Herman H. 
Published: April 2005

AbstractAim  To understand drivers of vegetation type distribution and sensitivity to climate change.Location  Interior Alaska.Methods  A logistic regression model was developed that predicts the potential equilibrium distribution of four major vegetation types: tundra, deciduous forest, black spruce forest and white spruce forest based on elevation, aspect, slope, drainage type, fire interval, average growing season temperature and total growing season precipitation. The model was run in three consecutive steps. The hierarchical logistic regression model was used to evaluate how scenarios of changes in temperature, precipitation and fire interval may influence the distribution of the four major vegetation types found in this region.Results  At the first step, tundra was distinguished from forest, which was mostly driven by elevation, precipitation and south to north aspect. At the second step, forest was separated into deciduous and spruce forest, a distinction that was primarily driven by fire interval and elevation. At the third step, the identification of black vs. white spruce was driven mainly by fire interval and elevation. The model was verified for Interior Alaska, the region used to develop the model, where it predicted vegetation distribution among the steps with an accuracy of 60–83%. When the model was independently validated for north‐west Canada, it predicted vegetation distribution among the steps with an accuracy of 53–85%. Black spruce remains the dominant vegetation type under all scenarios, potentially expanding most under warming coupled with increasing fire interval. White spruce is clearly limited by moisture once average growing season temperatures exceeded a critical limit (+2 °C). Deciduous forests expand their range the most when any two of the following scenarios are combined: decreasing fire interval, warming and increasing precipitation. Tundra can be replaced by forest under warming but expands under precipitation increase.Main conclusion  The model analyses agree with current knowledge of the responses of vegetation types to climate change and provide further insight into drivers of vegetation change.
Colonization of dynamic Mediterranean landscapes: where do birds come from after fire?
Authors: Brotons Lluís , Pons Pere , Herrando Sergi 
Published: April 2005

AbstractAim Two main mechanisms may explain post‐disturbance species colonization patterns of early successional habitats such as those originated by wildfires. First, post‐disturbance colonization is not limited by the dispersal ability of the species to reach the newly created open areas and, secondly, colonization is limited by dispersal. Under the first hypothesis, we expect, at a regional scale, to find similar post‐disturbance communities to develop on recently burned sites. However, colonization limited by dispersal will lead to strong between‐site variations in species composition.Location To test these hypotheses, we studied the post‐fire colonization patterns of nine open‐habitat bird species in eight distantly located wildfires in the north‐eastern Iberian Peninsula.Methods We censused post‐fire bird composition by means of field transects and identified potential colonization sources from species–habitat suitability maps derived from atlas data.Results Our results showed strong significant differences in post‐fire species composition between burnt areas. Burnt areas located in areas with low probability of species presence before the fire event showed lower species occurrence and richness after the fire.Main conclusions These results do not support the idea that early successional stages and open habitats have a homogeneous community structure at regional scales and suggest that dispersal is a key constraint determining bird colonization of post‐fire habitats. Further attention should be paid to landscape heterogeneity as a key factor in determining population dynamics of open‐habitat species in the light of current and future land‐use changes in Mediterranean regions.
Overexpression of Protein Kinase Cδ Enhances Cisplatin-Induced Cytotoxicity Correlated with p53 in Gastric Cancer Cell Line
Authors: Iioka Yoshihiko , Mishima Kenji , Azuma Nakanobu , Tsuchida Akihiko , Takagi Yu , Aoki Tatsuya , Saito Ichiro 
Published: April 2005

<i>Objective:</i> An important issue in cancer therapy is to investigate the mechanism for cellular sensitivity to anticancer agents such as cisplatin. Cisplatin is one of the DNA-damaging agents and several factors including p53 are related to the sensitivity to cisplatin in cancer. Protein kinase C (PKC) δ is known as a positive regulator for cisplatin-induced cell death. In our present study, we examined whether overexpression of PKCδ and p53 increases the sensitivity of the human gastric cancer cell line, MKN28, which has a mutation of p53 gene, to cisplatin. <i>Methods:</i> Cell viability and DNA content were measured in MKN28 with adenovirus-mediated expression of PKCδ and p53 after exposure to cisplatin. In addition, the active form of caspase-3 was detected by Western blotting. <i>Results:</i> Overexpression of exogenous PKCδ did not induce cell death in MKN28 but inhibited cell growth at 1 µg/ml cisplatin as compared to that by cisplatin alone. Moreover, overexpression of both wild-type p53 and exogenous PKCδ in MKN28 increased cisplatin-induced cell death in MKN28. <i>Conclusion:</i> These results suggest that PKCδ, in cooperation with p53, possibly regulates cisplatin-induced caspase-3-mediated cell death in gastric cancer.
Elastin-Derived Peptides Induce a T-Helper Type 1 Polarization of Human Blood Lymphocytes
Authors: Debret Romain , Antonicelli Frank , Theill Aurore , Hornebeck William , Bernard Philippe , Guenounou Moncef , Le Naour Richard 
Published: April 2005

Objective—Increased level of elastin-derived peptides (EDPs) is observed in the serum of patients with manifestations of arterial diseases. We here investigated whether EDPs might exert, at systemic level, a regulatory role for the T-helper type 1 (Th-1)/Th-2 cellular immune response by human peripheral blood lymphocytes (PBLs) expressing the spliced-galactosidase (S-gal)–elastin receptor.Methods and Results—Using flow cytometry and Western blot analysis, we demonstrated that EDPs led to an activation of the S-gal-elastin receptor associated with cytokine production on PBLs and CD4+T cell subpopulations. The constitutive expression of the S-gal–elastin receptor at the surface of human PBLs was upregulated at the mRNA (RT-PCR) and protein (ELISA) levels on cell activation. In nonactivated and phytohemagglutinin-activated conditions, expressions of the predominant Th-2 cytokine interleukin-5 (IL-5) and IL-10 were reduced, whereas those of the major Th-1 cytokines interferon-γ and IL-2 were enhanced by EDPs. Furthermore, we evidenced that EDPs could not only potentiate the IL-12–induced Th-1 profile but also could reverse the Th-2 (over Th-1) profile induced by IL-4. Finally, Th-1 cytokine upregulation was associated to an increased activator protein-1 DNA binding and enhanced pro–matrix metalloproteinase-9 secretion.Conclusions—This study highlights the importance of EDPs as stimuli for Th-1 differentiation, whether T cells are in an inactivated state or already orientated toward a Th-1 (IL-12) or Th-2 (IL-4) response.
Intracellular and Surface Distribution of Monocyte Tissue Factor
Authors: Egorina Elena M. , Sovershaev Mikhail A. , Bjørkøy Geir , Gruber Franz X.E. , Olsen Jan O. , Parhami-Seren Behnaz , Mann Kenneth G. , Østerud Bjarne 
Published: April 2005

Objective—The high and low responder phenomenon describes individual differences in lipopolysaccharide (LPS)-induced monocyte tissue factor (TF) activity. We characterized patterns of intracellular accumulation, externalization, and shedding of TF in response to LPS in mononuclear cells (MNCs) from high responders (HRs) and low responders (LRs).Methods and Results—After 2 hours of LPS stimulation of whole blood, flow cytometry analyses revealed a larger population of TF-positive monocytes in HRs (32.0±3.5%) versus LRs (11.2±1.2%;P≤0.05), along with a stronger mean fluorescence intensity of TF signal in HRs (7.1±0.5 arbitrary units [AU]) compared with LRs (5.4±0.4 AU;P≤0.05). The LPS-treated blood of the HR group contained 2-fold more TF-positive microparticles than LRs. In-cell Western assay demonstrated higher intracellular accumulation of TF in mononuclear cells (MNCs) from LRs because LPS induced a 3.7-fold increase of total TF levels in LRs versus a 1.5-fold increase in HRs. In contrast, in response to LPS stimulation, MNCs from HRs exhibited a 4-fold induction of surface TF, whereas MNCs from LRs only had a minor increase in surface TF levels.Conclusions—The higher availability of surface TF antigen on MNCs from HRs and TF-containing microparticles might make these individuals more susceptible to hypercoagulation.
fMRI Evidence for the Role of Recollection in Suppressing Misattribution Errors: The Illusory Truth Effect
Authors: Mitchell Jason P. , Dodson Chad S. , Schacter Daniel L. 
Published: April 2005

Abstract
Misattribution refers to the act of attributing a memory or idea to an incorrect source, such as successfully remembering a bit of information but linking it to an inappropriate person or time [Jacoby, L. L., Kelley, C., Brown, J., & Jasechko, J. (1989). Becoming famous overnight: Limits on the ability to avoid unconscious influences of the past. Journal of Personality and Social Psychology, 56, 326–338; Schacter, D. L. (1999). The seven sins of memory: Insights from psychology and cognitive neuroscience. American Psychologist, 54, 182–203; Schacter, D. L. (2001). The seven sins of memory: How the mind forgets and remembers. Boston: Houghton Mifflin]. Cognitive studies have suggested that misattribution errors may occur in the absence of recollection for the details of an initial encounter with a stimulus, but little is known about the neural basis of this memory phenomenon. Here we used functional magnetic resonance imaging (fMRI) to examine the hypothesized role of recollection in counteracting the illusory truth effect, a misattribution error whereby perceivers systematically overrate the truth of previously presented information. Imaging was conducted during the encoding and subsequent judgment of unfamiliar statements that were presented as true or false. Event-related fMRI analyses were conditionalized as a function of subsequent performance. Results demonstrated that encoding activation in regions previously associated with successful recollection—including the hippocampus and the ventrolateral prefrontal cortex (PFC)—correlated with the successful avoidance of misattribution errors, providing initial neuroimaging support for earlier cognitive accounts of misattribution.