bluuebunny/crossref_metadata_2025 huggingface dataset:
A case report: Bone marrow mesenchymal stem cells from a rett syndrome patient are prone to senescence and show a lower degree of apoptosis
Authors: Squillaro Tiziana , Hayek Giuseppe , Farina Ernesto , Cipollaro Marilena , Renieri Alessandra , Galderisi Umberto
Published: December 2007

Rett syndrome (RTT) is one of the most common genetic diseases responsible for a progressive disabling neurodevelopmental disorder. Mutations in the MeCP2 gene were identified in the great majority of RTT patients. MeCP2 protein binds to methylated DNA and produces changes in chromatin structure. This is a key event in regulation of gene expression. It has been suggested that MeCP2 might be important for neuronal development. Moreover, the frequent occurrence of osteoporosis and scoliosis in RTT patients suggests impaired bone formation and/or remodeling. Mesenchymal stem cells (MSCs) can differentiate as mesodermal cells such as bone, cartilage cells, and adipocytes. MSCs have been shown to possess great somatic plasticity; in fact, they can differentiate as neurons and astrocytes. We studied RTT patients' MSCs because they are progenitors of osteocytes, and it has been suggested that RTT patients' osteogenesis could be impaired. Moreover, MSCs might represent a useful model for the study of neurogenesis. MSCs from RTT patient showed precocious signs of senescence in a comparison with the MSCs of healthy‐patient control groups. This was in agreement with the reduced gene‐expression in the control of stem cell self‐renewal and upregulation of lineage specific genes, such as those involved in osteogenesis and neural development. Control groups enabled us to observe a lower degree of apoptosis in RTT patient cells. This means that aberrant stem/progenitor cells, instead of being eliminated, can survive and become senescent. Our research provides a new insight into RTT syndrome. Senescence phenomena could be involved in triggering RTT syndrome‐associated diseases. J. Cell. Biochem. 103: 1877–1885, 2008. © 2007 Wiley‐Liss, Inc.
Mycoplasma infection transforms normal lung cells and induces bone morphogenetic protein 2 expression by post‐transcriptional mechanisms
Authors: Jiang Shan , Zhang Shimin , Langenfeld John , Lo Shyh‐Ching , Rogers Melissa B.
Published: December 2007

Bone morphogenetic protein 2 (BMP2) is an essential growth factor and morphogen, whose pattern and level of expression profoundly influences development and physiology. We present the novel finding that mycoplasma infection induces BMP2 RNA production in six cell lines of diverse types (mesenchymal, epithelial, and myeloid). Mycoplasma infection triggered the expression of mature secreted BMP2 protein in BEAS‐2B cells (immortalized human bronchial epithelial cells), which normally do not express BMP2, and further increased BMP2 production in A549 cells (lung adenocarcinoma cells). Indeed, mycoplasma is as strong an experimental inducer as inflammatory cytokines and retinoic acid. Second, we showed that post‐transcriptional mechanisms including regulation of RNA stability, rather than transcriptional mechanisms, contributed to the increased BMP2 expression in mycoplasma‐infected cells. Furthermore, a novel G‐rich oligonucleotide, AS1411 that binds the post‐transcriptional regulator nucleolin induced BMP2 exclusively in infected cells. Finally, BMP2 stimulated proliferation in BEAS‐2B cells transformed by chronic mycoplasma infection, as demonstrated by treatment with Noggin, a BMP2 antagonist. These findings have important implications regarding the effects of mycoplasma on BMP2‐regulated processes, including cell proliferation, differentiation, and apoptosis. J. Cell. Biochem. 104: 580–594, 2008. © 2007 Wiley‐Liss, Inc.
Pregnancy in chronic renal failure: A novel cause of theca lutein cysts at MRI
Authors: Chen Eric M. , Breiman Richard S. , Sollitto Richard A. , Coakley Fergus V.
Published: December 2007

We describe the MRI findings of bilateral ovarian theca lutein cysts in a pregnant patient with chronic renal failure. The recognition that pregnancy in chronic renal failure may result in theca lutein cysts, presumably due to excessive serum beta human chorionic gonadotropins (hCGs) secondary to impaired renal excretion, expands the differential diagnosis for this MRI appearance, in addition to the usual considerations of gestational trophoblastic disease, multiple gestation, and ovarian hyperstimulation. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Voxel‐based analysis of R2* maps in the healthy human brain
Authors: Péran Patrice , Hagberg Gisela , Luccichenti Giacomo , Cherubini Andrea , Brainovich Valentina , Celsis Pierre , Caltagirone Carlo , Sabatini Umberto
Published: December 2007

Purpose

To develop a voxel‐based analysis of an R2* map of healthy human brain that is automatic, reproducible, and realizable in a single examination on a 3T MR imager. Such a tool could be useful to measure iron accumulation in neurodegenerative diseases.

Materials and Methods

In all, 18 healthy subjects underwent MR imaging at a field strength of 3T: 1) six consecutive T2*‐weighted gradient‐echo volumes were acquired using a segmented echo‐planar imaging sequence and 2) a conventional dual‐echo turbo spin echo sequence was also applied to acquire T2‐weighted images. Images were realigned and spatial correction was performed using a template brain dataset with SPM2. For each subject we performed a voxel‐by‐voxel nonlinear least‐squares fitting of the data acquired at the six echo times to obtain a monoexponential signal decay curve. The reproducibility and sensitivity to age variation were assessed by voxel‐based analysis.

Results

The reproducibility tests in whole brain analysis showed little R2* variation. Furthermore, the statistical analysis, performed on each brain voxel, revealed a significant positive correlation between age and MR values located in regions where a slow and constant age‐related iron deposition is known.

Conclusion

Our method, combining data acquisition and data processing, demonstrates the feasibility of voxel‐based analysis on an R2* map and affords a high degree of sensitivity and good reproducibility while maintaining high spatial resolution. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Extending slice coverage for breathhold fat‐suppressed T2‐weighted fast spin‐echo of the liver at 3.0T: Application of variable‐rate selective‐excitation (VERSE) RF pulses
Authors: van den Bos Indra C. , Hussain Shahid M. , Krestin Gabriel P. , Wielopolski Piotr A.
Published: December 2007

Purpose

To determine the benefits of variable‐rate selective‐excitation (VERSE) radio frequency (RF) pulses for increased slice coverage in breathhold (BH) fat‐suppressed T2‐weighted fast spin‐echo (FS‐T2W‐FSE) liver imaging at 3.0T.

Materials and Methods

A total of 12 healthy volunteers were imaged on 3.0T, using FS‐T2W‐FSE. Slice coverage and specific absorption rate (SAR) levels were monitored for VERSE‐RF and standard‐RF (sRF), respectively. BH time was 25 seconds; slice thickness 3.5 mm. Maximum coverage was recorded for interactive variation of repetition time (TR), bandwidth (BW), and echo‐train length (ETL). Image quality was assessed qualitatively and quantitatively.

Results

Total slice coverage was always higher using VERSE‐RF, but varied depending on the selected parameters. For BW ≥ 62.5 kHz, slice coverage using VERSE increased between 38% (TR = 8200 msec) and 58% (TR = 2500 msec). Maximum coverage was obtained for TR = 5000 msec, ETL = 12, and BW ≥ 62.5 kHz; with a mean of 31.8 slices for VERSE‐RF and 22.5 slices for sRF, respectively (P < 0.005, 41% increased coverage). SAR was lower for VERSE‐RF using BW < 41.67 kHz (P < 0.05), and equal to sRF for higher BW. Image quality was best for TR ≤ 5000 msec (P < 0.05). FS was more homogeneous for lower ETL (P < 0.05). Blood suppression was best for TR ≤ 5000 msec (P < 0.05).

Conclusion

VERSE‐RF pulses can be applied for thin‐slice BH FS‐T2W liver imaging at 3.0T, with significantly improved slice coverage. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
How does coaching interviewees affect the validity of a structured interview?
Authors: Maurer Todd J. , Solamon Jerry M. , Lippstreu Michael
Published: December 2007

Coaching interviewees to perform in employment interviews can influence the interview scores. We describe different types of coaching, emphasizing interventions designed to focus interviewees on core, interview‐relevant content and to help them convey the content accurately (as opposed to interventions designed to teach interviewees to manipulate their scores using peripheral means). We then study the effects of the former type of intervention in relation to the criterion‐related validity of a structured employment interview. In a combined sample of 146 public safety job incumbents, a predictive validation study was conducted using scores from a situational panel interview. Predictive validity and reliability was observed to be higher in a sample of coached interviewees compared to a sample of uncoached interviewees. Implications for future research and practice in organizational behavior are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Intermolecular H‐bond in propan‐2‐ol and its solutions with acetonitrile
Authors: Tukhvatullin F. H. , Jumabaev A. , Hushvaktov H. , Absanov A. , Shaymanov A.
Published: December 2007

Formation of propan‐2‐ol–acetonitrile dimers is manifested in the Raman spectra as an appearance of a band of aggregates in the high‐wavenumber side of the CN vibrational band of liquid acetonitrile (∼2 cm−1). The intensity of the band of aggregates changes with a change in the concentration of the mixture (1–0.05 mole fraction).

For propan‐2‐ol we carried out nonempirical calculations of a structure of isolated dimer aggregates. The formation of an intramolecular H‐bond between the H and the O atom of the
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group of length 2.045 Å is possible in the monomer molecule. The CH3 groups of alcohol are not equivalent. In the dimer formation, intramolecular H‐bond in the \newbox\osprulebox
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group is preserved. An intermolecular H‐bond of length 2.045 Å and energy 15 kJ/mole is formed between the H atom of one molecule and the O atom of another molecule of the OH. The length and energy of the H‐bond for the propan‐2‐ol–acetonitrile dimer formations calculate to 2.27 Å and 12.9 kJ/mole, respectively. The H‐bond is formed by σ‐electrons of nitrogen. The experimental data and the results of calculations are in good agreement. Copyright © 2007 John Wiley & Sons, Ltd.
Concentration dependent Raman and IR study on salicylaldehyde in binary mixtures
Authors: Fathima A. Anis , Umadevi M. , Ramachandran M. S. , Ramakrishnan V.
Published: December 2007

A vibrational spectroscopic study of binary mixtures of salicylaldehyde (SA) in three different solvents (polar and nonpolar) is presented. The vibrational modes ν(CO), hydroxyl stretching mode (COH) and aldehydic (CH) stretching vibration were analyzed. Changes in wavenumber position and full width half maximum have been explained for neat as well as binary mixtures with different volume fractions of the reference system, SA, in terms of inter‐ and intramolecular hydrogen bonding. The IR spectra of these mixtures have also been taken and compared with the Raman data. The spectral changes have been well explained using the concentration fluctuation model and solute–solvent interaction. Copyright © 2007 John Wiley & Sons, Ltd.
Influence of the Thiol Structure on the Kinetics of Thiol‐ene Photopolymerization with Time‐Resolved Infrared Spectroscopy
Authors: Wutticharoenwong Kosin , Soucek Mark D.
Published: December 2007

Photopolymerization kinetics of difunctional thiols with alkenes were studied. Two of the thiols, trans‐1,4‐bis(mercaptomethyl)cyclohexane (CHDMT) and 1,4‐bis(mercaptomethyl)benzene (BDMT) were synthesized. The CHDMT was synthesized via a two step process using potassium thioacetate and hydrochloric acid as reagents. The BDMT was synthesized by a one step process using 1,4‐benzenedimethanebromine with thiourea and potassium hydroxide as reagents. Three types of alkenes (divinyl ether, diallyl ether, and dimethacrylate) were reacted with CHDMT, BDMT or 1,8‐octanedithiol (ODT). The photopolymerization was investigated with and without a photoinitiator. The kinetics of the thiol‐ene photopolymerization was investigated by time‐resolved infrared spectroscopy. It was proposed that the steric hindrance of the cyclohexane (CHDMT) resulted in a lower rate of photopolymerization compared to BDMT and ODT. The vinyl ether (alkene) exhibited the highest activity compared to allyl ether and acrylate which was attributed to a high electron density of the alkene. Incorporation of photoinitiator increased the reaction rate and final conversion of the system, particularly in the ODT system.

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Nano‐Explosions of Nanoparticles for Sudden Release of Substances by Embedded Azo‐Components as Obtained via the Miniemulsion Process
Authors: Volz Marissa , Walther Paul , Ziener Ulrich , Landfester Katharina
Published: December 2007

The solid and thermally instable azoinitiators V‐65 and VR‐110 were embedded within a polymer particle by using the miniemulsion process and afterwards quickly decomposed by thermal treatment below the glass temperature of the polymer. The resulting nitrogen gas overpressure inside the particles leads to a disruption of the polymer particle and a possible sudden release of encapsulated substances. It is shown, by electron microscopic measurements, that the number of burst particles correlates with the applied temperatures as well as the heating time. The surface deformation could be verified by scanning electron microscope analyses.

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Dart Impact Testing of Polyethylene Film: Mechanical Interpretation and Model
Authors: Kissin Yury V.
Published: December 2007

A physical model of dart impact tests of film manufactured from semi‐crystalline polyethylene resins is developed. The models treat the dart impact tests as a special case of the standard high‐speed stress/strain measurement performed on a polymer sample with a linearly changing cross section. They describe the dart impact strength as a complex function of the parameters that characterize the stress‐strain curve of the resin: stresses and strains at the yield, necking and breaking points. The models correctly predict the range of the dart impact strength (ASTM D1709, ISO 7765) and are suitable for semi‐quantitative characterization and ranking of linear low density polyethylene resins for film applications.

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Imaging cadavers: Cold FLAIR and noninvasive brain thermometry using CSF diffusion
Authors: Tofts Paul S. , Jackson Jonathan S. , Tozer Daniel J. , Cercignani Mara , Keir Geoffrey , MacManus David G. , Ridgway Gerard R. , Ridha Basil H. , Schmierer Klaus , Siddique Durre , Thornton John S. , Wroe Stephen J. , Fox Nick C.
Published: December 2007

There is increasing interest in imaging cadavers for noninvasive autopsies for research purposes. However, the temperature is well below that of in vivo imaging, and a variety of interesting ‘cold brain’ effects are observed. At lower temperatures conventional FLAIR sequences no longer produce dark cerebrospinal fluid (CSF);T1is reduced from about 4.0 sec in vivo to 1.7 sec at 1°C. The diffusion coefficient (DC) of CSF is much reduced (from 3.1 10−9m2s−1in vivo to 1.1 at 1°C). DC values therefore provide a noninvasive thermometer to measure brain core temperature to within 1.0°C. In three cadavers DC values were 1.1–1.5 10−9m2s−1, indicating brain core temperatures of 1–10°C, consistent with external thermocouple measurements. An improved inversion time (TI0) can then be found for FLAIR. At 10°C this Cold FLAIR sequence (TI0= 1.5 sec) gave black CSF. Expressions for CSF DC andT1as a function of temperature were produced. A measurement of CSF DC could be converted directly to temperature and the required TI0found. In vitro values of CSF DC were about 1% lower than that of water. Thus, FLAIR imaging can be optimized for cadaveric brains at low and unknown temperatures, thereby improving value for autopsy purposes and facilitating comparisons with in vivo imaging. Magn Reson Med, 2007. © 2007 Wiley‐Liss, Inc.
Debt, democratization, and development in Latin America: How policy can affect global warming
Authors: Aubourg René W. , Good David H. , Krutilla Kerry
Published: December 2007

The environmental Kuznets curve (EKC) hypothesis conjectures a nonlinear relationship between pollution and economic growth, such that pollution per capita initially increases as countries economically develop, but then reaches a maximum point before ultimately declining. Much of the EKC literature has focused on testing this basic hypothesis and, in studies that find evidence of an EKC, estimating the “turning point” level of development at which the per capita pollution‐growth relationship changes sign. This approach has not emphasized the policy relevance of specification issues or the potential role of policy variables. This research explores a modified EKC specification which conditions the pollution‐growth relationship on a country's level of debt and degree of democratization. These variables turn out to be significant, implying that different political and economic contexts can shift EKCs and their turning points. These findings suggest that policies to relieve debt burdens and institute political reform, in addition to their usual justifications, also could be used as a strategy to reduce carbon emissions from developing countries. © 2008 by the Association for Public Policy Analysis and Management.
Natural rubber filled SiC and B4C ceramic composites as a new NTC thermistors and piezoresistive sensor materials
Authors: Todorova Z. , Dishovsky N. , Dimitrov R. , El‐Tantawy Farid , Abdel Aal N. , Al‐Hajry A. , Bououdina M.
Published: December 2007

A novel electrically conductive composite for NTC thermistor and piezoresistive sensor was successfully fabricated by homogeneously dispersing conductive SiC and B4C in an insulating natural rubber (NR) matrix. The morphology of the composites was investigated by means of scanning electron microscopy, cross linking density (n), volume fraction of rubber (Vr), and interparticle distance among conductive phases (rp). The influence of the filler concentrations on the mechanical properties such as modulus of elasticity (E); hardness shore A (H), and elongation at break (EB) were studied in details. The dependences of volume resistivity of NR based composites filled with B4C and SiC as a function of fillers concentration was investigated. Temperature dependencies of volume resistivity were also measured to examine the possible application of the composites to polymer linear negative temperature (NTC) thermistors. Furthermore, the temperature dependencies of dielectric constant of the composites were studied. For practical application, the thermal stability of the composites was examined by means of resistivity temperature and pressure hysteresis cycle. In parallel, the conduction mechanism of conductivity of the composites was interpreted in terms of the computed the activation and hopping energy. The applicability of the composites to piezoresistive sensor was examined too. The good mechanical properties and thermal stability of NR composites behavior can be utilized for fabricating various electronic devices as NTC thermistors and piezoresistive sensor (i.e. transducers in pressure sensors). POLYM. COMPOS., 29:109–118, 2008. © 2007 Society of Plastics Engineers
Analytical and experimental evaluation of elastic properties of vacuum assisted resin infusion molded polymer composites with eight‐harness woven fiber mats
Authors: Khattab Ahmed , El‐Gizawy A. Sherif
Published: December 2007

An analytical and experimental evaluation of elastic properties of composite materials under tensile load is presented in this paper. The analysis focuses on composite materials molded by vacuum assisted resin infusion molding (VARIM). The molded composite structure consists of AS4‐8 harness carbon fiber mats and a high‐temperature polymer (5250‐4‐RTM). The analytical model presented is adapted and formulated using optical microscopy observations of cross sections of samples molded by VARIM. Effects of resin degree of cure, fiber undulation, and resin rich areas between fiber bundles are addressed in the model. An experimental case study is presented to evaluate the accuracy of the adapted analytical model. The evaluation shows a reasonable agreement between the experimental and analytical results. POLYM. COMPOS., 29:63–71, 2008. © 2007 Society of Plastics Engineers
Synthesis of chitin calcium phosphate composite in different growth media
Authors: Geçer Aylin , Yıldız Nuray , Erol Murat , Çalımlı Ayla
Published: December 2007

This paper presents some results concerning chitin calcium phosphate composites obtained in different growth media. The synthesis of chitin calcium phosphate composite was carried out by phosphorylation, calcification, and soaking in different calcium phosphate growth media. This research is focused on studying and understanding the effect of using different growth media on composite samples. Hydroxyapatite was determined in the composite samples synthesized by using both simulated body fluid (SBF) and calcium phosphorus tris (Ca‐PTris) solution. Calcium/phosphorus (Ca:P) ratio of the composite synthesized by using SBF was found higher than that of composite synthesized by using Ca‐PTris solution as calcium phosphate growth media. The Ca:P ratio of the composite (1.72) immersed in 1.5× SBF for 35 day is similar to the theoretical value of hydroxyapatite (1.67) and closer to the theoretical value of human bone (1.75). POLYM. COMPOS., 29:84–91, 2008. © 2007 Society of Plastics Engineers
Flexibility at Different Stages in the Life Cycle of Projects: An Empirical Illustration of the “Freedom to Maneuver”
Authors: Olsson Nils O. E. , Magnussen Ole M.
Published: December 2007

Many textbooks on project management present illustrations concerning the relative size of project attributes during different project phases. The derived models all have attributes in common, such as uncertainty, significance of decisions, and degree of freedom to maneuver, that are typically high in the beginning of the project and low in the end. At the same time, variables such as the accumulated cost and available information begin at low levels and end up at a high level at the end of the project. Based on empirical data from projects, this paper illustrates and quantifies one of these attributes, the freedom to maneuver, in different project phases.
Measuring Performance in New Product Development Projects: A Case Study in the Aerospace Industry
Authors: Chiesa Vittorio , Frattini Federico , Lazzarotti Valentina , Manzini Raffaella
Published: December 2007

Implementing a performance measurement system (PMS) for research and development (R&D) is fundamental for supporting decision making and motivating researchers and engineers; however, this is a very challenging task, because effort levels are not measurable and success highly uncertain. Even if the subject has largely been debated in academic and practitioners literature so far, an acknowledged managerial approach is not available yet. This paper investigates the implementation and use of a PMS in new product development (NPD) projects, which represents a relatively unexplored issue in the R&D performance measurement debate. In particular, studying the case of a military aircraft development project, it provides a reference framework that integrates the major literature contributions’ findings and suggests a practical approach for the design and implementation of an effective PMS for NPD.
New Product Development Projects: The Effects of Organizational Culture
Authors: Belassi Walid , Kondra Alex Z. , Tukel Oya Icmeli
Published: December 2007

Despite the increasing use of project management within organizations, an attendant poor rate of success among these projects has been observed (Clancy & Stone, 2005; Ives, 2005). Seventy-five percent of all business transformation projects fail (Collyer, 2000) and only 16% of U.S. IT projects are completed on time and on budget (Peled, 2000). In an attempt to overcome such a high project failure rate, this paper investigates the effects of organizational culture on the performance of particular types of projects: new product development (NPD) projects. Using data from 95 U.S. organizations, the study provides evidence of the significant effects of organizational culture on NPD projects.
A Negotiation Approach to Project Sales and Implementation
Authors: Kujala Jaakko , Murtoaro Jarkko , Artto Karlos
Published: December 2007

We conceive the project sales and implementation process as a continuous joint decision-making process between the customer and supplier. We draw a parallel between the stage model of negotiations and phases of the project sales and implementation process, and apply the framework of negotiation analysis to the context of project management. A sample of negotiation strategies for both counterparts is presented to illustrate how the negotiation analytic framework can be used to describe and analyze different strategies the supplier and customer can employ in different phases of the project sales and implementation process. We find that a qualitative application of the approach facilitates the description of generic negotiation maneuvers in projects, supports the analysis of project negotiations, and provides several practical suggestions to improve negotiation outcomes.
Motivation: How to Increase Project Team Performance
Authors: Peterson Tonya M.
Published: December 2007

Stimulating team member performance requires a project manager to harness many different interpersonal skills. The level of enthusiasm applied toward project efforts has a direct impact on the project results. Because motivation can inspire, encourage, and stimulate individuals to achieve common goals through teamwork, it is in the project manager's best interest to drive toward project success through the creation and maintenance of a motivating environment for all members of the team.
Acid catalyzed intramolecular attack of β‐phenylthioureido group on amide function. Parallel formation of thiodihydrouracil and 4‐iminothiodihydrouracil. Different pathways in the Edman degradation reaction in the formation of six‐ versus five‐membered cyclic intermediates
Authors: Pojarlieff Ivan G. , Blagoeva Iva B. , Toteva Maria M. , Atay Ergun , Angelova Violina T. , Vassilev Nikolay G. , Koedjikov Asen H.
Published: December 2007

Contrary to the cleavage of α‐phenylthioureido peptides 1 proceeding through intermediate 2‐anilinothiazolinone 2, the b‐analog cis‐2‐(3‐phenylthioureido)cyclopentane‐carboxamide 5 forms transiently 4‐imino‐2‐thioxopyrimidine 6. Monitoring amide cyclization and hydrolysis of iminopyrimidine 6 in acid by UV showed that an equilibrium between 5 and 6 was reached followed by slower conversion of both compounds into 2‐oxo‐4‐thioxopyrimidine 7. Both processes were characterized by isosbestic points, the first due to parallel conversion of 5 into 6 and 7 (or 6 into 5 and 7) at a constant ratio while the second identical for both reactants – to conversion of equilibrated 5 and 6 into 7. The special isosbestic points allowed the determination of the individual constants of Scheme 2. Further confirmation was obtained from NMR product analysis and following the cyclization of amide 5 in DMSO:DCl. Product 2‐oxo‐4‐ thioxopyrimidine 7 hydrolyzed reversibly to thioureido acid 8. The cyclization rate of 8 allowed the participation of 6‐oxothiazine 10 formed by sulfur attack to be excluded. The absence of sulfur attack in the six‐membered case is explained by the longer CS bond bringing about greater bond angle strain at the tetrahedral ring atoms due to the geometrical characteristics of five‐ and six‐membered rings with planar segments. The cyclizations of amide 5 to iminopyrimidine 6 and to thiodihydrouracil 7 are first order in [H+], while the reactions of protonated imine 6H+ are zero order to amide and −1 to thiodihydrouracil. The reaction orders can be reconciled by assuming a rate determining proton transfer from the tetrahedral intermediate in amide cyclization. Copyright © 2007 John Wiley & Sons, Ltd.
Deprotonation and radicalization of glycine neutral structures
Authors: Yang Gang , Zu Yuangang , Zhou Lijun
Published: December 2007

Ab initio calculations at MP2/6‐311++G(d,p) theoretical level were performed to study the deprotonation and radicalization processes of 13 glycine neutral structures (A. G. Császár, J. Am. Chem. Soc. 1992; 114: 9568). The deprotonation processes to glycine neutral structures take place at the carboxylic sites instead of α‐C or amido sites. Two carboxylic deprotonated structures were obtained with the deprotonation energies calculated within the range of 1413.27–1460.03 kJ · mol−1, which are consistent with the experimental results. However, the radicalization processes will take place at the α‐C rather than carboxylic O or amido sites, agreeing with the experimental results. Seven α‐C radicals were obtained with the radical stabilization energies calculated within the range of 44.87–111.78 kJ · mol−1. The population analyses revealed that the main conformations of the neutral or radical state are constituted by several stable structures, that is, the other structures can be excluded from the future considerations and thus save computational resources. Copyright © 2007 John Wiley & Sons, Ltd.
Reaction of poly‐L‐lysine with aryl acetates and aryl methyl carbonates. A mechanistic study
Authors: Castro Enrique A. , Echevarria Gerardo R. , Opazo Alejandra , Robert Paz S. , Santos José G.
Published: December 2007

The pH profile (log k vs. pH) of the reactions of poly‐L‐lysine (PL) with a series of aryl acetates and aryl methyl carbonates in aqueous solution show the same conformational changes as those determined by potentiometric titrations. When PL is a random coil, the most probable mechanism for the reactions studied is through the formation of a tetrahedral intermediate and its breakdown to products as the rate‐determining step. The tetrahedral intermediate is stabilized by a hydrogen bond interaction between the nitro groups in the substrate and the NH group of the principal chain or some NH2 groups of the lateral chains. Copyright © 2007 John Wiley & Sons, Ltd.
Structural and spectroscopic investigations of non‐planar tris(dialkylamino)cyclopropenium cations
Authors: Butchard James R. , Curnow Owen J. , Pipal Robert J. , Robinson Ward T. , Shang Rong
Published: December 2007

The mixed triaminocyclopropenium cation bis(diisopropylamino)dimethylaminocyclopropenium was prepared from bis(diisopropylamino)chlorocyclopropenium by reaction with dimethylamine. It was isolated as the perchlorate salt and found to have a distorted structure in the solid state. Tris(diisopropylamino)cyclopropenium was prepared by reaction of pentachlorocyclopropane with diisopropylamine in a refluxing dichloroethane solution for 2 days. The solid state structure was found by X‐ray crystallography to have two planar amino groups and one pyramidal amino group, however, the 1H‐NMR and infrared solution spectra show equivalent isopropyl groups in solution. The compounds were also characterised by Raman and infrared spectroscopy. Additionally, a new polymorph of [C3(NMe2)3]ClO4 is described as well as the X‐ray structure of bis(diisopropylamino)cyclopropenone. Copyright © 2007 John Wiley & Sons, Ltd.
Is corannulene a better diene or dienophile? A DFT analysis
Authors: Jayapal Prabha , Sundararajan Mahesh , Rajaraman Gopalan , Venuvanalingam Ponnambalam , Kalagi Rashmi , Gadre Shridhar R
Published: December 2007

Diels Alder reactivity of corannulene has been probed using density functional theory (DFT) at B3LYP/6‐31G* level by employing it both as a diene and a dienophile in cycloaddition with ethylene and 1,3‐butadiene as typical partners. Computations reveal that corannulene acts better as a dienophile than as a diene and as a dienophile it undergoes normal electron demand type addition with 1,3‐butadiene, and as a diene corannulene undergoes inverse electron demand type addition with ethylene. When employed as a dienophile the addition takes place preferentially in the rim position than in the spoke position due to strong steric and electronic reasons. Further in the rim addition rim exo approach is favored kinetically and thermodynamically. As a diene, corannulene shows regioselectivity for rim–spoke addition over spoke–spoke addition. Concerted type cycloadditions have been studied and the reactions are seen to take place preferentially on the convex face. The effect of substituents in butadiene on the reactivity and the reaction of butadiene–pentaindenocorannulene (an extended corannulene) system has been investigated for the most favorable rim exo positions. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and self assembly of eosin functionalized amphiphilic block‐random copolymers prepared by ring opening metathesis polymerization
Authors: Sandholzer Martina , Fritz‐Popovski Gerhard , Slugovc Christian
Published: December 2007

Self assembly of block copolymers has gained considerable attention because of its potential use in various areas such as medical and biomedical applications, nanotechnology, and electronics. Herein, we present the synthesis and characterization of amphiphilic block‐random copolymers with a covalently incorporated pH‐sensitive dye, namely eosin. Ring opening metathesis polymerization was chosen for the preparation of well defined block copolymers and block‐random copolymers using a modified “2nd Generation Grubbs” initiator. The self assembly behavior of the block‐random copolymers in solution was studied by dynamic light scattering and small angle X‐ray scattering (SAXS). The influence of dye incorporation on the result of the self assembly process in methanol and ethanol was investigated and a subtle interplay of the nature of the selective solvent, the chain‐length of the block copolymer and the position of the dye within the polymer chain was established. Structural investigations using SAXS revealed a spherical shape and a core‐shell structure of exemplary block and block‐random copolymer micelles. UV–vis absorption and photoluminescence measurements revealed similar optical properties for polymer micelles in methanol compared to polymer solutions in THF. The pH‐sensitive behavior of the eosin dye was preserved within the micelles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 401–413, 2008
Synthesis, characterization, and properties of new thermally curable polyetheresters containing benzoxazine moieties in the main chain
Authors: Kiskan Baris , Yagci Yusuf , Ishida Hatsuo
Published: December 2007

High molecular weight polyetheresters (PEE) containing thermally curable benzoxazine units in the main chain have been synthesized. For this purpose, first the diol functional monomer is synthesized through the Mannich reaction of 4,4′‐isopropylidenediphenol (bisphenol A), formaldehyde, and 2‐(2‐aminoethoxy)ethanol. Polycondensation of the resulting benzoxazine dietherdiol with adipoyl chloride and terephthaloyl dichloride in the presence of triethyl amine yields the corresponding PEE with the molecular weights of 34.000 Da. The structures of the precursor diol monomer and the resulting PEEs are confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy (1H‐NMR) analysis. Curing behavior of both the monomer and polymers has also been studied by differential scanning calorimetry (DSC). Flexible free standing transparent films of the PEEs are obtained by solvent casting from dichloromethane solution on Teflon plates. The films preserve shape and, to some extent, toughness after thermal curing between 140 and 220 °C. Thermal properties of the cured polymers are also investigated by thermogravimetric analysis (TGA). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 414–420, 2008
Synthesis of triblock copolymers from glycolysed poly(ethylene terephthalate) by living radical polymerization
Authors: Colomines Gael , Otazaghine Belkacem , Boyer Cyrille , Monge Sophie , Robin Jean‐Jacques
Published: December 2007

Valorization of poly(ethylene terephthalate) (PET) waste has been achieved using glycolysis. The resulting diols were employed for the synthesis of triblock copolymers by atom transfer radical polymerization using copper (I) bromide and (1,1,4,7,10,10)‐hexamethyltriethylenetetramine as catalyst system. Macroinitiator was obtained after depolymerization of PET waste followed by functionalization of the obtained glycolysate with 2‐bromoisobutyrate bromide. Polymerization of styrene (S) and glycidyl methacrylate (GMA) has been achieved leading to PS‐b‐PETG‐b‐PS and (PS‐stat‐PGMA)‐b‐PETG‐b‐(PS‐stat‐PGMA) triblock copolymers. Best results were obtained at 100 °C. At this temperature, termination reaction were negligible and the measured number‐average molar mass of the product increased linearly with monomer conversion in agreement with the theoretical Mn with low polydispersity products achieved. Polymers were also characterized by 1H NMR. This work presents a original valorization of PET waste as (PS‐stat‐PGMA)‐b‐PETG‐b‐(PS‐stat‐PGMA) copolymer could be used as heat curable coatings. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 433–443, 2008
Molecular design of efficient white‐light‐emitting fluorene‐based copolymers by mixing singlet and triplet emission
Authors: Xu Yunhua , Guan Rong , Jiang Jiaxing , Yang Wei , Zhen Hongyu , Peng Junbiao , Cao Yong
Published: December 2007

A new strategy to realize efficient white‐light emission from a binary fluorene‐based copolymer (PF‐Phq) with the fluorene segment as a blue emitter and the iridium complex, 9‐iridium(III)bis(2‐(2‐phenyl‐quinoline‐N,C3′)(11,13‐tetradecanedionate))‐3,6‐carbazole (Phq), as a red emitter has been proposed and demonstrated. The photo‐ and electroluminescence properties of the PF‐Phq copolymers were investigated. White‐light emission with two bands of blue and red was achieved from the binary copolymers. The efficiency increased with increasing concentration of iridium complex, which resulted from its efficient phosphorescence emission and the weak phosphorescent quenching due to its lower triplet energy level than that of polyfluorene. In comparison with the binary copolymer, the efficiency and color purity of the ternary copolymers (PF‐Phq‐BT) were improved by introducing fluorescent green benzothiadiazole (BT) unit into polyfluorene backbone. This was ascribed to the exciton confinement of the benzothiadiazole unit, which allowed efficient singlet energy transfer from fluorene segment to BT unit and avoided the triplet quenching resulted from the higher triplet energy levels of phosphorescent green emitters than that of polyfluorene. The phosphorescence quenching is a key factor in the design of white light‐emitting polyfluorene with triplet emitter. It is shown that using singlet green and triplet red emitters is an efficient approach to reduce and even avoid the phosphorescence quenching in the fluorene‐based copolymers. The strategy to incorporate singlet green emitter to polyfluorene backbone and to attach triplet red species to the side chain is promising for white polymer light‐emitting diodes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 453–463, 2008
Effect of molecular architecture and size of mesogen on phase behavior and photoactive properties of photoactive liquid crystalline hyperbranched polyester epoxies containing benzylidene moiety
Authors: Srinivasa Rao V. , Samui A. B.
Published: December 2007

A series of photoactive liquid crystalline linear and hyperbranched polyester epoxies were synthesized by polyaddition of photoactive bis benzylidene alkanone diol monomers and terephthalic acid and trimesic acid respectively with good yield. The effect of molecular architecture (linear and hyperbranched), size of mesogenic unit (cyclic and acyclic units) on the physicochemical, thermal, mesogenic, and photoactive properties of hyperbranched polymers were studied and compared. Degree of branching of hyperbranched polymers was found to be in the range of 0.46–0.49. Monomers containing cyclic moieties only exhibited nematic mesophase, while all polymers exhibited typical nematic mesophase. Intermolecular photo cycloaddition reaction was studied by ultraviolet–visible spectra (UV–vis) and NMR spectroscopy and photo viscosity measurement of UV irradiated polymer solutions. Faster photo induced behavior of hyperbranched polymers containing acyclic alkanone moiety, as compared to polymers containing cycloalkanone moieties, was observed. The change in the refractive index was found to be in the range of 0.02–0.024. Substantial variation of refractive index indicates that this polymer could be used for optical recording. All the polymers were also found to be fluorescent in nature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 552–563, 2008
Proteomic characterization of Sophoraflavone J‐induced apoptosis in HepG2 cells
Authors: Cheung Crystal Sao‐Fong , Hon Po‐Ming , Fung Kwok‐Pui , Au Shannon Wing‐Ngor
Published: December 2007

Chinese herb Radix sophorae is widely applied as an anticarcinogenic/antimetastatic agent against liver cancers. In the current study, Sophoraflavone J, a flavonoid constituent enriched in the root of Radix sophorae, induced apoptosis in human hepatoma HepG2 cells via the intrinsic mitochondrial death pathway. The molecular mechanism of the cytotoxic effect was further investigated by a comparative proteomic approach. Differentially expressed proteins identified included membrane proteins/antigens, structural proteins, transcriptional factors, glycolytic enzymes, heat‐shock chaperon proteins, ROS‐related proteins and proteosomes, etc. These findings were further validated by Western blot analysis and real‐time PCR. Preliminary experiments to characterize the roles of these proteins were conducted. Our data suggested that Sophoraflavone J treatment triggered nutrient depletion and generation of ROS in cells, which subsequently led to mitochondrial dysfunction and apoptosis.
Apolipoprotein A1: A new serum marker correlated to JAK2 V617F proportion at diagnosis in patients with polycythemia vera
Authors: Mossuz Pascal , Bouamrani Ali , Brugière Sabine , Arlotto Marie , Hermouet Sylvie , Lippert Eric , Laporte François , Girodon François , Dobo Irène , Vincent Praloran , Garin Jérome , Cahn Jean Yves , Berger François
Published: December 2007

Polycythemia vera (PV) is a myeloproliferative disorder (MPD) characterized by an acquired gain‐of‐function mutation of the JAK2 protein (JAK2 V617F). Allele‐specific quantitative PCR has showed a JAK2 V617F dosage effect on haematological and clinical parameters of PV at diagnosis, but it is unknown whether the level of certain serum proteins might correlate with the proportion of mutated JAK2. Taking into account that such proteins could represent useful prognostic marker, we investigated the serum protein profile of PV patients by SELDI‐TOF MS. We identified apolipoprotein A1 (Apo‐A1) as a serum marker correlated to the percentage of JAK2 V617F alleles; Apo‐A1 expression being the highest for PV patients with more than 75% of mutated alleles. Immuno‐assay on an automated random immuno‐analyser confirmed the correlation between Apo‐A1 concentrations and JAK2 V617F percentages, and showed that serum Apo‐A1 assay allowed the specific discrimination of PV patients with high levels of mutated alleles (≥75%). These data suggest that Apo‐A1 assay could be a useful assay for the stratification of PV patients at diagnosis.
Utilizing endoscopic technology to reveal real‐time proteomic alterations in response to chemoprevention
Authors: Nakanishi Masako , Ménoret Antoine , Belinsky Glenn S. , Giardina Charles , Godman Cassandra A. , Vella Anthony T. , Rosenberg Daniel W.
Published: December 2007

Cancer chemoprevention approaches use either pharmacological or dietary agents to impede, arrest or reverse the carcinogenic process. Although several agents have shown effectiveness against colon cancer, present intervention strategies provide only partial reduction. In this study, we utilized high‐resolution endoscopy to obtain colon tumor biopsy specimens from Apc mutant mice before and after 2‐wk sulindac intervention. To acquire information beyond genomics, proteome analysis using the ProteomeLab PF2D platform was implemented to generate 2‐D protein expression maps from biopsies. Chromatograms produced common signature profiles between sulindac and nonsulindac treated samples, and contrasting profiles termed “fingerprints”. We selected a double peak that appeared in tumor biopsies from sulindac‐treated mice. Further analyses using MS sequencing identified this protein as histone H2B. The location of H2B in the 1st dimension strongly suggested PTM, consistent with identification of two oxidized methionines. While further studies on sulindac proteomic fingerprints are underway, this study demonstrates the feasibility and advantages of “real‐time” proteomic analysis for obtaining information on biomarker discovery and drug activity that would not be revealed by a genetic assay. This approach should be broadly applicable for assessing lesion responsiveness in a wide range of translational and human clinical studies.
Pharmacological studies on hypotensive, diuretic and vasodilator activities of chrysin glucoside from Calycotome villosa in rats
Authors: Cherkaoui‐Tangi K. , Lachkar M. , Wibo M. , Morel N. , Gilani A. H. , Lyoussi B.
Published: December 2007

The present study was undertaken in normotensive anaesthetized male rats that received a continuous perfusion of a chrysin glucoside isolated from the flowers and leaves of Calycotome villosa subsp intermedia at a dose of 2.5 mg/kg, or furosemide (control diuretic) at a dose of 0.5 mg/kg. Compared with the control rats receiving NaCl (0.9%), the urine flow, glomerular filtration and electrolyte excretion (Na+, K+) increased significantly in rats treated with chrysin glucoside (p < 0.001). A similar effect was observed in the rats perfused with furosemide. Intravenous injections of bolus doses (1–3 mg/kg) of the chrysin glucoside to anaesthetized rats elicited an immediate and dose‐dependent decrease in mean arterial blood pressure (MABP). Pretreatment of the rats with the nitric oxide synthase inhibitor, l‐NOArg (10 mg/kg), reduced partially, but significantly (p < 0.01), the maximal decrease in MABP elicited by chrysin glucoside. In the rat isolated aorta preparation, chrysin glucoside (10–100 µm) inhibited in a concentration‐dependent manner the noradrenaline (1 µm) induced contractions (IC50 = 52 µm). This relaxant activity of chrysin glucoside was significantly reduced by incubation of the endothelium‐intact rings with l‐NOArg (100 µm), (80 ± 4.7% vs 48 ± 5.06% in the absence of l‐NOArg). In conclusion, these results demonstrate a diuretic and hypotensive action of a chrysin glucoside from Calycotome villosa in anaesthetized rats and indicating an action on renal function, and an active vascular relaxation mediated partially through nitric oxide release. Copyright © 2007 John Wiley & Sons, Ltd.