bluuebunny/crossref_metadata_2025 huggingface dataset:
Thymosin beta‐4 directs cell fate determination of human mesenchymal stem cells through biophysical effects
Authors: Hui‐Chun Ho Jennifer , Ma Wei‐Hsien , Su Yeu , Tseng Kuang‐Ching , Kwang‐Chun Kuo Tom , Kuang‐Sheng Lee Oscar
Published: July 2009

Change of actin filament organization at the early stage of cell differentiation directs cell fate commitment of mesenchymal stem cells (MSCs). Thymosin beta‐4 (Tβ4), a major G‐actin sequestering peptide, is known to regulate the cytoskeleton. The study investigated the ways in which Tβ4 regulates cell fate determination in MSCs upon differentiation induction. It was found that Tβ4 decreased F‐actin formation, reduced the F‐actin/G‐actin ratio, and inhibited osteogenic differentiation; such actin reorganization was not associated with the change of Runt‐related transcription factor 2 gene expression during early osteogenic induction. Besides, Tβ4 reciprocally facilitated adipogenic differentiation. Tβ4 treatment was found to up‐regulate gene as well as promote surface expression of adipocyte adhesion molecule during early adipogenic differentiation, which accompanied acceleration of adipocyte phenotypic maturation but was not associated with differential expression of peroxisome proliferator‐activated receptor gamma during the first week of adipogenic induction. In summary, Tβ4 initiated cell fate determination of MSCs through biophysical effects exerted by cytoskeleton reorganization and altered cell‐cell adhesion rather than direct regulation of lineage‐determining transcriptional factors. Such findings suggest that Tβ4, a ubiquitous peptide, may be involved in osteoporosis when its intracellular concentration is elevated. Further investigation of targeting Tβ4 for future osteoporosis treatment is warranted. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:131–138, 2010
An animal model for open femur fracture and osteomyelitis: Part I
Authors: Lindsey Brock A. , Clovis Nina B. , Smith E. Suzanne , Salihu Sydha , Hubbard David F.
Published: July 2009

Infection is an everyday problem in orthopaedics and is quite common in open fracture management. To study this process and provide a basis to prevent infection, we developed a model that includes trauma (blunt fracture in the fashion of Bonnarens and Einhorn), surgical stabilization (standardized intramedullary K‐wire fixation), and infection (Staphylococcus aureus inoculum). In this two‐part study, we found that 102 colony‐forming units of inoculum produced an optimal infection rate of 90–100%, which substantially challenged the immune system without overwhelming sepsis. We hypothesized that, in traumatic fractures, there is a specific immunological response that may lead to an increased rate of infection. In Part 2, we demonstrated immunosuppression (decreased Interleukin‐12 levels) at days 6, 10, and 12 after fracture fixation versus nonfractured control groups (p < 0.05). This study describes a rat model of femur factures with osteomyelitis that allows investigation of posttraumatic immunosuppression. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:38–42, 2010
Protonatable Ionenes for Nucleic Acid Complexation
Authors: Ramirez Sean M. , Layman John M. , Long Timothy E.
Published: July 2009

Novel tboc‐protected ionenes with $\overline M _{\rm w}$ exceeding 30 kDa were prepared from the step‐growth polymerization of tert‐butyl bis[3‐(dimethylamino)propyl]carbamate and 1,12‐dibromododecane. The protected ionenes yielded pH‐sensitive, protonatable ionenes with pKa ≈ 6.6 for the conjugate acid of the protonated secondary amine. Polyplexes of the protected and deprotected ionenes, whose cytotoxicity for endothelial cells was analyzed using the MTT assay, efficiently complex plasmid DNA. Polyplexes destabilized cellular membranes as revealed using the lactate dehydrogenase assay at high concentrations. The polyplexes were successfully transfected into HBMECs at mass ratios 2, 4, 8, 12, and 16 (polymer/DNA) at polyplex concentrations less than 10 µg · mL−1.

magnified image
Sustained and Extended Release with Structural and Activity Recovery of Lysozyme from Complexes with Sodium (Sulfamate Carboxylate) Isoprene/Ethylene Oxide Block Copolymer
Authors: Gao Gao , Yan Yunfeng , Pispas Stergios , Yao Ping
Published: July 2009

The complexation of lysozyme and sodium (sulfamate carboxylate) isoprene/ethylene oxide (SCIEO) at pH = 7.4 and the release of lysozyme from the complexes in the presence of NaCl were investigated. Through electrostatic and hydrophobic interactions, lysozyme and SCIEO form stable complex nanoparticles. The complexation partially disturbs the structure of lysozyme. Some of the hydrophobic residues of lysozyme are exposed to bind with SCIEO. The complexation leads to loss of most of the lysozyme activity. In the presence of NaCl, lysozyme can be released from the complexes. The released lysozyme molecules recover their native structure and activity completely. In the condition of physiological pH and ionic strength, a sustained and extended release of lysozyme was achieved.

magnified image
Synthesis of Liquid‐Crystalline Colloids in Nonpolar Media and their Manipulation in Electric Fields
Authors: Haseloh Sönke , Zentel Rudolf
Published: July 2009

The first synthesis of anisotropic liquid‐crystalline colloids in silicone oil by a direct (radical) polymerization of a monomer in THF/silicone oil mixtures with the help of siloxane containing stabilizers is described. The size of the colloids is in the lower µm range and can be adjusted by varying the mixture. The resulting colloids show a bipolar director configuration if they are small (<1.5 µm) and a radial configuration if they are larger. The colloids are sterically stabilized, and, due to the nonpolarity of the solvent, the disturbing effects of migrating ions are excluded and experiments in the electric field can be conducted. Both line formation in DC fields and a periodic switching of the bipolar colloids in AC fields is observed.

magnified image
Comparison of High‐Temperature HPLC, CRYSTAF and TREF for the Analysis of the Chemical Composition Distribution of Ethylene‐Vinyl Acetate Copolymers
Authors: Albrecht Andreas , Brüll Robert , Macko Tibor , Malz Frank , Pasch Harald
Published: July 2009

The chemical composition distribution (CCD) is a fundamental molecular parameter of copolymers. High‐temperature interactive liquid chromatography (HT‐HPLC) has recently emerged as a new analytical technique for determination of the CCD of semicrystalline copolymers of ethylene and polar comonomers. With the aim of comparing the results of HT‐HPLC with those from the traditionally used temperature rising elution fractionation (TREF) and crystallization analysis fractionation (CRYSTAF) techniques, three ethylene‐vinyl acetate (EVA) copolymers were fractionated by TREF and the fractions were analyzed by HT‐HPLC. HT‐HPLC‐Fourier transform‐infrared (FT‐IR) spectroscopy showed that individual fractions of different VA‐content coelute in the HPLC. While the separation in TREF and CRYSTAF is mainly the result of the overall effect of alkyl branches and VA‐comonomer units, in HT‐HPLC it is the polar comonomer that selectively contributes to the adsorption. Thus, HT‐HPLC leads to a much more detailed knowledge of the distribution of the structured units; in addition, it saves time.

magnified image
Generation of Ag Nanoparticles by PAMAM Dendrimers and their Size Dependence on the Aggregation Behavior of Dendrimers
Authors: Kavitha Manniledam , Parida Manas R. , Prasad Edamana , Vijayan C. , Deshmukh P. C.
Published: July 2009

Stable silver nanoparticles were generated in aqueous medium by amine, hydroxy and carboxylate terminated poly(amidoamine) (PAMAM) dendrimers in the absence of conventional reducing agents and light irradiation. Mechanistic studies suggest that, in spite of their lower pKa values, tertiary amines present in the dendritic structures act as the reducing agent. Dynamic light scattering and electron microscopic studies reveal that PAMAM dendrimers aggregate in presence of silver ions and the aggregation propensity plays a pivotal role in altering the size and shape of the nanoparticles generated in the dendritic milieu. The formation of metal nanoparticles with uniform size and shape by amine terminated PAMAM dendrimer is attributed to the unique aggregation propensity of amine terminated PAMAM.

magnified image
Macroporous Materials from Self‐Assembling Synthetic Cyclic Peptide‐Based Compounds and Deposition of Dipeptide‐Capped Gold Nanoparticles on the Surfaces
Authors: Guha Samit , Banerjee Arindam
Published: July 2009

Two cyclic peptides are separately self‐assembled, one on top of the other, utilizing non‐covalent interactions – mainly intermolecular hydrogen bonding – to form a one‐dimensional array. These one‐dimensional arrays are further self‐assembled to construct macroporous materials. This is shown from TEM, AFM and FE‐SEM analyses. These materials have been used for adsorption and desorption of nitrogen gas. Moreover, they can act as suitable templates for the deposition of dipeptide capped gold nanoparticles on the surfaces of macroporous structures.

magnified image
Controlling Orientation and Functionalization in Thin Films of Block Copolymers
Authors: Lee Chansub , Kim Seung Hyun , Russell Thomas P.
Published: July 2009

Functionalizing and controlling nanostructures resulting from block copolymer self‐assembly are key factors in defining their application. In this work, a simple but quite general route to achieve both goals simultaneously is discussed. In thin films of polystyrene‐block‐poly(vinyl pyridine) (PS‐b‐PVP) with small concentrations of a gold salt, the salt is found to complex with the PVP block which leads to an orientation of the microdomains normal to the surface after solvent annealing together with functionalization. By increasing the amount of gold salt, on the other hand, micelles are found to form in solutions leading to a range of different morphologies in the thin films.

magnified image
Novel Highly Active Niobium Catalysts for Ring Opening Metathesis Polymerization of Norbornene
Authors: Raspolli Galletti Anna Maria , Pampaloni Guido , D'Alessio Aldo , Patil Yogesh , Renili Filippo , Giaiacopi Simone
Published: July 2009

Ring‐opening metathesis polymerization (ROMP) of norbornene catalyzed by niobium(V) N,N‐dialkylcarbamates Nb(O2CNR2)5, R = Et (1), Me (2) was studied in the presence of methylaluminoxane (MAO) as a cocatalyst. These novel catalytic systems resulted very active in chlorobenzene: 1 in the presence of methylaluminoxane catalyzes the ROMP of norbornene with the highest activity (29 000 kg of polymer/mol of catalyst × hour) never reported up to now for niobium catalysts. The high productivity appears particularly attractive considering that these precursors are rather cheap and easy to synthesize and to handle. Polynorbornenes were characterized by FT‐IR and NMR spectroscopies and by DSC calorimetry. A new FT‐IR method for the swift determination of the cis/trans content of the polymer is presented.

magnified image
Application of WET sequence for the detection of the ligand signals resonating close to water
Authors: Furihata Kazuo , Shimotakahara Sakurako , Shibusawa Yoichi , Tashiro Mitsuru
Published: July 2009

An efficient pulse sequence for observing the ligand signals resonating close to the water signal has been developed by incorporating the WET technique into the saturation transfer difference pulse sequence. Although several pulse sequences have been developed for observing a ligand binding with a protein receptor, the ligand signals resonating close to the water were undetectable owing to the interference of the huge water signal in the samples containing 95% 1H2O. On the point of sample preparation, it is preferable to avoid the solvent exchange in the protein samples. In the proposed pulse sequence, a WET sequence is incorporated for the selective suppression of the water resonance. The efficient water suppression and the clear observation of the bound ligand signals close to the water have been demonstrated using the lysozyme‐glucose complex. Copyright © 2009 John Wiley & Sons, Ltd.
Calibration of a discrete element model for intact rock up to its peak strength
Authors: Wang Yuannian , Tonon Fulvio
Published: July 2009

When three dimensional, bonded discrete element models (DEMs) are deployed to model intact rock, a basic question is how to determine the micro parameters that control macro properties of the modeled rock. After briefly describing the authors' DEM code, this paper describes algorithms to calibrate the model's micro parameters against standard laboratory tests, such as uniaxial and triaxial tests. Sensitivity analysis is used to identify the deformability micro parameters by obtaining relationships between microscopic and macroscopic deformability properties. The strength model parameters are identified by a global optimization process aimed at minimizing the difference between computed and experimental failure envelopes. When applied to the experimental results of Lac du Bonnet granite, this calibration process produced a good agreement between simulated and experimental results for both deformability and strength properties. Copyright © 2009 John Wiley & Sons, Ltd.
Algebraic multigrid and 4th‐order discrete‐difference equations of incompressible fluid flow
Authors: Webster R.
Published: July 2009

This paper investigates the effectiveness of two different Algebraic Multigrid (AMG) approaches to the solution of 4th‐order discrete‐difference equations for incompressible fluid flow (in this case for a discrete, scalar, stream‐function field). One is based on a classical, algebraic multigrid, method (C‐AMG) the other is based on a smoothed‐aggregation method for 4th‐order problems (SA‐AMG). In the C‐AMG case, the inter‐grid transfer operators are enhanced using Jacobi relaxation. In the SA‐AMG case, they are improved using a constrained energy optimization of the coarse‐grid basis functions. Both approaches are shown to be effective for discretizations based on uniform, structured and unstructured, meshes. They both give good convergence factors that are largely independent of the mesh size/bandwidth. The SA‐AMG approach, however, is more costly both in storage and operations. The Jacobi‐relaxed C‐AMG approach is faster, by a factor of between 2 and 4 for two‐dimensional problems, even though its reduction factors are inferior to those of SA‐AMG.

For non‐uniform meshes, the accuracy of this particular discretization degrades from 2nd to 1st order and the convergence factors for both methods then become mesh dependent. Copyright © 2009 John Wiley & Sons, Ltd.
An analytical approximation for solving nonlinear Blasius equation by NHPM
Authors: Aminikhah Hossein
Published: July 2009

In this article, an analytic approximation to the solution of Blasius equation is obtained by using a new modification of homotopy perturbation method. The Blasius equation is a nonlinear ordinary differential equation which arises in the boundary layer flow. The comparison with Howart's numerical solution shows that the new homotopy perturbation method is an effective mathematical method with high accuracy. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Assessment of ProteoExtract subcellular fractionation kit reveals limited and incomplete enrichment of nuclear subproteome from frozen liver and heart tissue
Authors: Murray Christopher I. , Barrett Meagan , Van Eyk Jennifer E.
Published: July 2009

The nuclear fraction of the ProteoExtract subcellular fractionation kit was assessed using frozen rat liver and heart tissue. Fractionation was evaluated by Western blot using protein markers for various subcellular compartments and followed up with LC/MS/MS analysis of the nuclear fractions. Of the proteins identified, nuclear proteins were in the minority (less than 15%) and there was poor representation of the various nuclear substructures when compared with liver nuclear isolations using a classical density‐based centrifugation protocol. The ProteoExtract kit demonstrated poor specificity for the nucleus and offers limited promise for proteomics investigations of the nuclear subproteome in frozen tissue samples.
Identification of apolipoproteinA1 reduction in the polycystic kidney by proteomics analysis of the Mxi1‐deficient mouse
Authors: Yoo Kyung Hyun , Kim Yo Na , Lee Min Joo , Seong Je Kyung , Park Jong Hoon
Published: July 2009

Autosomal dominant polycystic kidney disease is one of the most common human monogenic diseases in which extensive epithelial‐lined cysts develop in kidney and other organs. Affected kidneys are not only characterized by the formation of cysts, but also by changes associated with the extracellular matrix and interstitial inflammation, which can progress to fibrosis and loss of renal function. Mxi1 protein, which is a c‐myc antagonist, may be essential in controlling cellular growth and differentiation. Previously, multiple tubular cysts were observed in kidney of Mxi1‐deficient mice aged 6 months and more. Presently, 2‐DE and MALDI‐TOF MS was employed to identify the differentially expressed proteins in the kidney. Several proteins were identified, among them, apolipoproteinA1 which is a major component of the high‐density lipoprotein complex and has anti‐inflammation effects, was significantly decreased in the Mxi1‐deficient mouse. We confirm the development of inflammation and renal fibrosis and the expression of extracellular matrix molecules including transforming growth factor were also increased in cystic kidney. These results indicate that expression of proteins related with inflammation and renal fibrosis changes by Mxi1 inactivation in polycystic kidney.
Generation of high‐quality protein extracts from formalin‐fixed, paraffin‐embedded tissues
Authors: Addis Maria Filippa , Tanca Alessandro , Pagnozzi Daniela , Crobu Salvatore , Fanciulli Giuseppe , Cossu‐Rocca Paolo , Uzzau Sergio
Published: July 2009

A wealth of information on proteins involved in many aspects of disease is encased within formalin‐fixed paraffin‐embedded (FFPE) tissue repositories stored in hospitals worldwide. Recently, access to this “hidden treasure” is being actively pursued by the application of two main extraction strategies: digestion of the entangled protein matrix with generation of tryptic peptides, or decrosslinking and extraction of full‐length proteins. Here, we describe an optimised method for extraction of full‐length proteins from FFPE tissues. This method builds on the classical “antigen retrieval” technique used for immunohistochemistry, and allows generation of protein extracts with elevated and reproducible yields. In model animal tissues, average yields of 16.3 μg and 86.8 μg of proteins were obtained per 80 mm2 tissue slice of formalin‐fixed paraffin‐embedded skeletal muscle and liver, respectively. Protein extracts generated with this method can be used for the reproducible investigation of the proteome with a wide array of techniques. The results obtained by SDS‐PAGE, western immunoblotting, protein arrays, ELISA, and, most importantly, nanoHPLC‐nanoESI‐Q‐TOF MS of FFPE proteins resolved by SDS‐PAGE, are presented and discussed. An evaluation of the extent of modifications introduced on proteins by formalin fixation and crosslink reversal, and their impact on quality of MS results, is also reported.
What can the geometry tell about the charge distribution in the mesoionic heterocycles? A DFT study on the SCN4R2 system
Authors: Irshaidat Tareq
Published: July 2009

This computational organic chemistry study was performed using the hybrid functional B3LYP. Many basis sets were evaluated and the basis set 6‐31G(d) was found to be the most practical in terms of time and accuracy. The study presents the first method in the chemical literature that allows estimation of submolecular charges in mesoionic compounds. The theory was built on a reference model structure for which the absolute value of charge of the aromatic p‐orbitals is known. This is the cornerstone, and by employing the harmonic oscillator model of aromaticity (HOMA) many parameters can be quantified. The electronic structure of the title compound was the subject of this approach. The study addressed the following points: geometries, infrared frequencies, NMR chemical shifts, calculated charges, a chemical reactivity, and the frontier orbitals. The calculations illustrate that the π‐system of the CN4 segment includes considerable aromatic character and carries a positive charge while the overall charge is negative. This allows classifying it as a σ‐acceptor/π‐donor while the exocyclic counter anion, the sulfur atom, is a σ‐donor/π‐acceptor. The substituents (R groups) in this case are only σ‐donors. The approach may be applied to other mesoionic and mesoaromatic systems. Copyright © 2009 John Wiley & Sons, Ltd.
Electron reorganization in allowed and forbidden pericyclic reactions: multicenter bond indices as a measure of aromaticity and/or anti‐aromaticity in transition states of pericyclic electrocyclizations
Authors: Mandado Marcos , Ponec Robert
Published: July 2009

The multicenter bond indices (MCI), recently proposed as quantitative measures of cyclic delocalization in aromatic systems, have been applied to characterize the differences in the nature of the electron reorganization in a series of allowed and forbidden electrocyclic reactions of linear neutral polyenes of general formula CnHn+2and related charged systems of formula CnHn+2(+) and CnHn+2(−) fornranging from 4 to 7. The proposed methodology, which is based on the monitoring of the variation of the extent of cyclic delocalization along the concerted reaction paths, is shown to be completely consistent with the empirical Evans/Dewar classification anticipating aromatic transition states for allowed and anti‐aromatic transition states for forbidden electrocyclic reactions. Although the study reports the results of the analysis of electron reorganization just for the above‐mentioned particular class of electrocyclic reactions, the proposed approach is completely general and its conclusions remain valid for any pericyclic reaction. Copyright © 2009 John Wiley & Sons, Ltd.
Polyrotaxanes based on polyethers and β‐cyclodextrin
Authors: Chelli Saloua , Majdoub Mustapha , Aeiyach Salah , Jouini Mohamed
Published: July 2009

A polyrotaxane in which β‐cyclodextrins (β‐CDs) are threaded onto a polyether chain was prepared by polycondensation of a β‐CD/bisphenol A (BPA) inclusion complex with aromatic dihalides. Two dihalides, with and without a side chain, were used. This polycondensation results in a polyrotaxane (or pseudopolyrotaxane for polymers without stoppers) with a 1:1 threading ratio when the side chain is present and 2:3 when there is none. The long side chain prevents dethreading of the macrocycles. The best yield and a good threading ratio were obtained when the polycondensation was performed by liquid−solid phase transfer catalysis without solvent (L/S PTC) using 2,5‐bi(iodomethyl)‐4‐methoxy‐(1‐octyloxy)benzene as dihalide. The 1H NMR and FTIR spectra show that the products consist of β‐CD and polyether. The 2D NOESY NMR spectrum shows that the polyether chains are included in the β‐CD cavity. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4391–4399, 2009
The Cancer Pain Inventory: preliminary development and validation
Authors: Deshields Teresa L. , Tait Raymond C. , Manwaring Jamie , Trinkaus Kathryn M. , Naughton Michael , Hawkins Josephine , Jeffe Donna B.
Published: July 2009

Objective: The purpose of this study was to develop a Cancer Pain Inventory (CPI) that measures cancer patients' beliefs and concerns about pain. This paper describes development and pilot testing of a preliminary version of the CPI and describes its psychometric properties including its reliability and validity relative to established pain measures.

Methods: Subjects were recruited from inpatient and outpatient oncology services of an NCI‐designated comprehensive cancer center. Participants completed the 50 potential CPI items and these standard measures—Orientation‐Memory‐Concentration Test, Survey of Pain Attitudes, Brief Pain Inventory, Pain Disability Index, and Center for Epidemiological Studies—Depression Scale. The magnitude and significance of associations between the CPI and the other measures were examined.

Results: Of 366 patients who were eligible and agreed to participate in the study, 262 completed the questionnaires. Principal components analyses were used to select items most appropriate for retention in the preliminary version of the CPI and to describe its factor structure. Based on the content of items that loaded on each factor, the five factors were labeled as Catastrophizing, Interference with Functioning, Stoicism, Social Aspects, and Concerns about Pain Medication. Correlations between the CPI and other measures supported construct validity of the five CPI factors.

Conclusions: The results supported the validity of the CPI as a measure of five constructs relevant to the experience of pain in the cancer setting. The results also underscored the presence of unique features of cancer‐related pain that clearly differ from commonly recognized dimensions of chronic, non‐cancer‐related pain. Copyright © 2009 John Wiley & Sons, Ltd.
Physical and mental health correlates of pregnancy following breast cancer
Authors: Gorman Jessica R. , Roesch Scott C. , Parker Barbara A. , Madlensky Lisa , Saquib Nazmus , Newman Vicky A. , Pierce John P.
Published: July 2009

Introduction: The safety of pregnancy after breast cancer is an important issue for many younger breast cancer survivors and their health care providers. Current research does not indicate that pregnancy negatively affects survival, but the ‘healthy mother bias,’ suggesting that survivors who go on to become pregnant are a self‐selected healthier group based on their prognosis, has led to cautious interpretation of these findings. No studies have systematically evaluated the potential for this bias.

Methods: This nested case–control study includes 81 younger participants from the Women's Healthy Eating and Living (WHEL) study (N=3088). Our sample includes 27 cases who had children after breast cancer and 54 controls, matched on age and stage at diagnosis. We used hierarchical linear modeling to accommodate longitudinal data with individuals nested within matched sets (cases and controls). The primary aim was to evaluate the association between summary scores of health and childbearing after breast cancer. Covariates were added for adjustment and to improve model precision.

Results: Controlling for other variables in the model, physical health scores were not different between cases and controls (B=0.14, p=0.96). Mental health scores were marginally higher among cases (B=6.40, p=0.08), as compared with controls, a difference considered clinically significant.

Conclusion: This preliminary study did not find evidence of a healthy mother bias based on physical health. However, mental health was 6 points higher (p=0.08) among those who had children, indicating that the role of mental health needs evaluation in future research. Larger studies are needed to verify these findings. Copyright © 2009 John Wiley & Sons, Ltd.
Application of Thin Layer Chromatography for Monitoring of FOX‐7 Synthesis
Authors: Błądek Jan , Pietrzyk Sylwia , Cudziło Stanisław , Chyłek Zbigniew
Published: July 2009

In this paper, results of the research on the application of thin layer chromatography (TLC) for the determination of 1,1‐diamino‐2,2‐dinitroethene (FOX‐7, DADNE) and its precursors produced in the synthetic path starting from 2‐methylpyrimidine‐4,6(1H,5H)‐dione are presented. Analytical parameters of the substances and methodology of their quantitative analysis were determined, and the results obtained were used for monitoring the FOX‐7 synthesis process.
Structural and optical characterization of pulsed laser‐ablated potassium lithium niobate thin films
Authors: Jayasree V. , Ratheesh R. , Rao P. Prabhakar , Koshy Peter , Ganesan V. , Nayar V. U. , Pillai V. P. Mahadevan
Published: July 2009

Thin films of potassium lithium niobate (K3Li2Nb5O15: KLN) have been prepared on glass substrate, as a function of substrate temperature, using a pulsed laser‐deposition (PLD) technique for the first time. Grazing‐incidence X‐ray diffraction (GIXRD) analysis suggests that KLN films can be grown successfully at a substrate temperature as low as 300 K. The anomalous behavior of the decline of crystalline structure with increase in substrate temperature is explained. The atomic force microscopic (AFM) and scanning electron microscopic (SEM) images show an agglomerated growth mode for the films deposited at a substrate temperature of 300 K and a decrease in grain size with increase in substrate temperature. The films deposited at higher substrate temperatures show ring‐like structures. The AFM analysis shows that the rms surface roughness of the film decrease with increase in substrate temperature. The UV–Vis transmission spectra suggest that the nature of the transition in the films is directly allowed. A blue shift in optical bandgap is observed for the films compared to bulk material. The changes in the optical bandgap with substrate temperature are also discussed.
Measurement of the spatial coherence of synchrotron beams using the Talbot effect
Authors: Kluender Rafael , Masiello Fabio , van Vaerenbergh Pierre , Härtwig Jürgen
Published: July 2009

We present an application of the Talbot effect [Talbot et al., Philos. Mag. 11, 196 (1836)] to measure the spatial coherence of a synchrotron beam, as well as the influence of optical elements on it. One advantage of using this effect is that regions of the beams down to 50 µm × 50 µm are still analysable (in our case). This spatial resolution allows analysing the local coherence degradation caused by small regions in the investigated optical element, like windows or Bragg diffraction crystals with defects. A second advantage is the independence of the results on the detector point spread function. This method is used by the Optics and the X‐ray Imaging Group at the ESRF in the hard X‐ray domain at 20.5 keV. Although already presented by Cloetens et al., J. Synchrotron Radiat. 11, 476 (2004), this technique was mainly used to analyse the spatial beam coherence itself. In order to measure the coherence degradation due to non‐perfect optical elements, we improved the data analysis which was very deficient when applied to diffractive samples. These improvements have led to accurate and reliable results and have allowed to extend the application field of that method towards diffracting crystals.
Structural and photoluminescence studies of erbium‐implanted nanocrystalline silicon thin films
Authors: Cerqueira M. F. , Alpuim P. , Filonovich S. A. , Alves E. , Rolo A. G. , Andres G. , Soares J. , Kozanecki A.
Published: July 2009

Hydrogenated amorphous and nanocrystalline silicon thin films deposited by hot wire (HW) and radio‐frequency plasma‐enhanced chemical vapour deposition (RF‐PECVD) were erbium‐implanted. Their pre‐implantation structural properties and post‐implantation optical properties were studied and correlated. After 1 h annealing at 150 °C in nitrogen atmosphere only amorphous films showed photoluminescence (PL) activity at 1.54 µm, measured at 5 K. After further annealing at 300 °C for 1 h, all the samples exhibited a sharp PL peak positioned at 1.54 µm, with an FWHM of ∼5 nm. Amorphous films deposited by HW originated a stronger PL peak than corresponding films deposited by RF, while in nanocrystalline films PL emission was much stronger in samples deposited by RF than by HW. There was no noticeable difference in Er3+ PL activity between films implanted with 1 × 1014 and 5 × 1015 atoms cm−2 Er doses.
Electrical and optical properties of LixNi1–xO/In:MgxZn1–xO heteroepitaxial junction grown on TiN buffered Si
Authors: Wong H. F. , Wong K. H. , Lau C. H.
Published: July 2009

P‐type Li doped NiO (LNO) and n‐type In doped cubic MgxZn1–xO (In:MZO) thin films were grown on TiN buffered Si (100) substrates by pulsed laser deposition. A heteroepitaxial relationship of (001)LNO||(001)In:MZO ||(001)TiN||(001)Si was obtained. These heterostructures showed good p–n junction current–voltage characteristics with a current rectification ratio of 400 at bias voltages of ±4 V. The typical current turn‐on voltage at room temperature was 2.8 V. It decreased to 2.6 V at 400 K. The spectral responses of these heterojunctions were measured in the near UV region. Our results have suggested that LNO/In:MZO heterojunction is a potential candidate for Solar‐blind UV detector.
Towards printed magnetic sensors based on organic diodes
Authors: Majumdar Sayani , Majumdar Himadri S. , Tobjörk Daniel , Österbacka Ronald
Published: July 2009

We report a study of magnetotransport properties of regio‐regular poly(3‐hexyl thiophene) (RRP3HT)‐based organic diodes. The devices were fabricated using two different techniques namely spin coating and inkjet printing. Positive magnetoresistance (MR) effect was observed at room temperature in all the devices. The highest MR magnitude reached up to 16% for some spin‐coated devices and up to 10% in inkjet printed devices. The MR magnitude and line shapes were found to depend strongly on the measuring current. We observed deviation from the theoretically predicted Lorentzian or non‐Lorentzian line shape of the MR traces, which is discussed in detail in the article. Although, the printed devices exhibit MR response as high as for the spin‐coated ones, they still need to be optimised in terms of performance and yield for large scale applications as magnetic sensors.
Semimagnetic semiconductor oxides as materials for transparent electronics and spintronics
Authors: Savchuk A. I. , Makhniy V. P. , Fediv V. I. , Kleto G. I. , Savchuk S. A.
Published: July 2009

Zinc oxide‐based semimagnetic semiconductor (SMS) ZnMnO, ZnMnFeO and ZnMnSnO thin films were deposited on sapphire and glass substrate by pulsed laser deposition (PLD) and RF sputtering techniques. Further, ZnMnO nanocrystals embedded in polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) matrices were prepared by chemical method employing zinc acetate and manganese acetate as precursors. The morphology of the thin films was studied using atomic force microscopy (AFM). Large variety of the morphology images was obtained depending on the film composition and growth conditions. The most interesting feature was observed for the ZnMnSnO films, in which the formation of clusters including nanowire‐like structures was shown. Optical transmission spectra suggest that metals Mn, Fe and Sn substitute for Zn2+ ions in the ZnO lattice, resulting in the increase in the band gap energy. Magneto‐optical Faraday rotation measurements confirm ferromagnetic ordering in ZnMnFeO thin films and paramagnetic behaviour for the other films.
Micromechanical behaviour of gel grown pure and doped potassium hydrogen tartrate single crystals
Authors: Quasim I. , Firdous A. , Sahni N. , Khosa S. K. , Kotru P. N.
Published: July 2009

Micromechanical characteristics of (001) and (111) planes of gel grown pure, sodium‐ and lithium‐doped potassium hydrogen tartrate single crystals as revealed by indentation induced technique are described. The indentation size effect (ISE) exhibited by the crystals is explained on application of proportional specimen resistance (PSR) model and the analytical law of Hays and Kendall. The load independent values of Vickers hardness of (001) and (111) planes of these crystals as indicated by indentation experiments and computed on the basis of PSR model and the analytical law are shown to be in good agreement. The doping by sodium or lithium results in the increase in hardness of potassium hydrogen tartrate crystals. The crystals exhibit hardness anisotropy. The values of yield strength of each plane of both pure and sodium and lithium doped potassium hydrogen tartrate single crystals are estimated using appropriate equations.
Enhanced red emission of CaMoO4:Eu3+ phosphor by structural adjustment for white light‐emitting diodes application
Authors: Zhang Zhan Hui , Huang Qiang , Zhao Xu , Huang Zhi Liang
Published: July 2009

Na+ was incorporated into red‐emitting CaMoO4:Eu3+ phosphor to form solid solutions and reduce the crystal symmetry. For a fixed Eu3+ concentration, the luminescent properties as a function of Na+ concentrations were systematically studied under near‐ultraviolet (UV) excitation. Enhanced red emission at 613 nm was observed and the strongest intensity was 4.5 times that of the sample without Na+. Differing from the charge‐compensation mechanism, this enhancement was related to the structural distortion and decreasing centrosymmetry. The increased ratios of red emission (5D0 → 7F2) to orange (5D0 → 7F1) in intensity revealed that the structural adjustment was achieved in the phosphors via the incorporation of Na+.
Mesoporous GaAs double layers for layer transfer processes
Authors: Garralaga Rojas Enrique , Terheiden Barbara , Plagwitz Heiko , Hampe Carsten , Tutuc Daniel , Haug Rolf , Brendel Rolf
Published: July 2009

Mesoporous GaAs double layers with different porosities and thicknesses up to 7 µm are formed on highly doped p‐type 4 inch GaAs substrates by means of electrochemical etching in highly concentrated hydrofluoric acid electrolytes. Small 〈111〉 oriented pyramids form at the interface between porous layer and substrate if etching current densities below 7.5 mA cm−2are applied. Porous double layers with different porosities are obtained by varying simultaneously the etching current density and the electrolyte concentration. The porosity of the porous GaAs layers decreases nearly linearly from 69 to 53% with electrolyte concentrations increasing from 30 to 50 wt.%, respectively. The etching process increases the mean roughness of the porous layer surface from 0.15 to 0.24 nm.

magnified image
Oxygen‐assisted photoinduced structural transformation in amorphous Ge–S films
Authors: Sakaguchi Yoshifumi , Tenne Dmitri A. , Mitkova Maria
Published: July 2009

We report our results of continuous illumination of Ge46S54 chalcogenide glass films with bandgap light in air. The outcome of this process is the formation of Ge–S backbone depleted in germanium. We relate this to consumption of some of the germanium available in the initial material due to the occurrence of a photoinduced oxidation. This is proved using energy dispersion spectroscopy which shows the presence of 17.68 at.% oxygen in the glass post‐radiation. Raman spectra demonstrate that the initial material shows breathing modes, characteristic for Ge46S54 glass. After prolonged illumination Raman spectra reveal structure characteristic for the composition of the Ge–S backbone close to Ge33S67. The oxide forms a film on the surface and this changes the surface relief, studied by atomic force microscopy, but the oxidation is not surface‐limited. The oxidation process in these glasses is discussed and the higher priority of germanium oxidation compared to the oxidation of sulphur is stated.
Diffraction and luminescent structures based on chalcogenide glasses and polymers
Authors: Andriesh Andrei , Iovu Mihail
Published: July 2009

Diffraction optical structures are the main elements of diffraction optics with the perspectives for application in the systems of filtering, multiplexing, routing, focusing, and collimating of the light, as well as for fabrication of the photonic crystals. Thin films prepared from chalcogenide glasses and polymers were used for the fabrication of diffractive structures by holographic and electron‐beam recording technology. The electric field and other technological procedures have been used during the holographic writing process in order to increase the diffraction efficiency and the spatial density of the recording media. The problem of obtaining low‐cost but efficient luminescent materials is still present. It was shown that intensive luminescence is manifested from composite materials consisting of arsenic sulfide and arsenic selenide doped with rare‐earth ions (Dy3+and Pr3+), and polymers polyvinylalcohol or polyvinylpyrrolidone.
GaN layer growth by HVPE on m‐plane sapphire substrates
Authors: Usikov Alexander , Shapovalov Lisa , Ivantsov Vladimir , Kovalenkov Oleg , Syrkin Alexander , Spiberg Philippe , Brown Robert
Published: July 2009

Semipolar GaN layers were grown on m‐plane sapphire substrates by HVPE. Insertion of AlxGa1–xN (x ∼ 0.1‐0.6) layer in‐between m‐plane sapphire substrate and GaN layer promoted to improve crystalline quality and to grow of semipolar (11‐22) plane GaN layers. X‐ray diffraction (11‐22) ω‐scan rocking curve FWHM of 298 arcsec was measured for a 30 μm thick (11‐22) GaN layer. Depending on growth conditions, m‐plane GaN layer having micro‐crystallites of other orientations (mainly of (11‐24) plane GaN layer) was also grown. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cranberry proanthocyanidins are cytotoxic to human cancer cells and sensitize platinum‐resistant ovarian cancer cells to paraplatin
Authors: Singh Ajay P. , Singh Rakesh K. , Kim Kyu Kwang , Satyan K. S. , Nussbaum Roger , Torres Monica , Brard Laurent , Vorsa Nicholi
Published: July 2009

Polyphenolic extracts of the principal flavonoid classes present in cranberry were screened in vitro for cytotoxicity against solid tumor cells lines, identifying two fractions composed principally of proanthocyanidins (PACs) with potential anticancer activity. Matrix‐Assisted Laser Desorption/Ionization Time‐Of‐Flight Mass Spectrometry (MALDI‐TOF‐MS) analysis of the proanthocyanidins (PACs) fractions indicated the presence of A‐type PACs with 1–4 linkages containing between 2–8 epicatechin units with a maximum of 1 epigallocatechin unit. PACs exhibited in vitro cytotoxicity against platinum‐resistant human ovarian, neuroblastoma and prostate cancer cell lines (IC50 = 79–479 µg/mL) but were non‐cytotoxic to lung fibroblast cells (IC50 > 1000 µg/ml). SKOV‐3 ovarian cancer cells treated with PACs exhibited classic apoptotic changes. PACs acted synergistically with paraplatin in SKOV‐3 cells. Pretreatment of SKOV‐3 cells with PACs (106 µg/ml) resulted in a significant reduction of the paraplatin IC50 value. Similarly, in a BrdU incorporation assay, co‐treatment of SKOV‐3 cells with PACs and paraplatin revealed reduced cell proliferation at lower concentrations than with either individually. In SKOV‐3 cell cultures co‐treated with PAC‐1 and paraplatin, an HPLC analysis indicated differential quantitative presence of various PAC oligomers such as DP‐8, ‐9, ‐11 and ‐14 indicating either selective binding or uptake. Cranberry proanthocyanidins exhibit cell‐line specific cytotoxicity, induce apoptotic markers and augment cytotoxicity of paraplatin in platinum‐resistant SKOV‐3 ovarian cancer cells. Copyright © 2009 John Wiley & Sons, Ltd.
An exponentially weighted moving average control chart for Bernoulli data
Authors: Spliid Henrik
Published: July 2009

We consider a production process in which
units are produced in a sequential manner. The units can, for example, be man‐
ufactured items or services, provided to clients.Each unit produced can be a
failure with probability p or a success (non‐failure) with probability (1−p).
A novel exponentially weighted moving average (EWMA) control chart intended
for surveillance of the probability of failure, p, is described. The chart is based
on counting the number of non‐failures produced between failures in combina‐
tion with a variance‐stabilizing transformation. The distribution function of the
transformation is given and its limit for small values of p is derived. Control
of high yield processes is discussed and the chart is shown to perform very well
in comparison with both the most common alternative EWMA chart and the
CUSUM chart. The construction and the use of the proposed EWMA chart are
described and a practical example is given. It is demonstrated how the method
communicates the current failure probability in a direct and interpretable way,
which makes it well suited for surveillance of a great variety of activities in
industry or in the service sector such as in hospitals, for example. Copyright
© 2009 John Wiley & Sons, Ltd.
A Restrained Molecular Dynamics Empirical Approach for Generating a Small Set of Structures Representative of the Internal Flexibility of a Receptor
Authors: Aci‐Sèche Samia , Garnier Norbert , Genest Daniel , Bourg Stéphane , Marot Christophe , Morin‐Allory Luc , Genest Monique
Published: July 2009

Multiple protein structure methods have been proposed for incorporating protein flexibility in molecular docking. One approach for docking ligands onto a rigid receptor is to use an ensemble of multiple rigid structures determined experimentally by X‐ray or NMR spectroscopy or generated by numerical simulations. In this work we present an empirical method for generating a wide range of conformational states of a wobbling receptor using restrained Molecular Dynamics simulations (MD) and we propose a partitioning protocol for selecting a few representative conformations of the binding site from restrained MD sampling.
State‐feedback disturbance attenuation for polytopic LPV systems with input saturation
Authors: Yun Sung Wook , Choi Yun Jong , Park PooGyeon
Published: July 2009

This paper proposes a state‐feedback control law for linear parameter‐varying (LPV) systems with input saturation and disturbances. The proposed control law employs two control parts: a main control part for reducing the restricted ℒ︁2 gain from the mismatched disturbance to the controlled output and an extra control part for eliminating the matched disturbance. Owing to this feature, the proposed control law provides a better disturbance attenuation performance than the conventional control law that deals with a unified disturbance regardless of the presence of matched and mismatched disturbances. Further, considering different forms of the feedback gain matrix K(θ(t)) and the Lyapunov function V(x(t)), three types of controllers are proposed. For each type, set invariance and the restricted ℒ︁2 gain performance conditions are first formulated in terms of parameterized linear matrix inequalities (PLMIs) and then converted into linear matrix inequalities (LMIs) by using a parameter relaxation technique. Results from the simulation of numerical examples confirm the effectiveness of the proposed controllers. Copyright © 2009 John Wiley & Sons, Ltd.
Controlling Cellular Uptake by Surface Chemistry, Size, and Surface Topology at the Nanoscale
Authors: Massignani Marzia , LoPresti Caterina , Blanazs Adam , Madsen Jeppe , Armes Steven P. , Lewis Andrew L. , Battaglia Giuseppe
Published: July 2009

Cell cytosol and the different subcellular organelles house the most important biochemical processes that control cell functions. Effective delivery of bioactive agents within cells is expected to have an enormous impact on both gene therapy and the future development of new therapeutic and/or diagnostic strategies based on single‐cell–bioactive‐agent interactions. Herein a biomimetic nanovector is reported that is able to enter cells, escape from the complex endocytic pathway, and efficiently deliver actives within clinically relevant cells without perturbing their metabolic activity. This nanovector is based on the pH‐controlled self‐assembly of amphiphilic copolymers into nanometer‐sized vesicles (or polymersomes). The cellular‐uptake kinetics can be regulated by controlling the surface chemistry, the polymersome size, and the polymersome surface topology. The latter is controlled by the extent of polymer–polymer phase separation within the external envelope of the polymersome.