bluuebunny/crossref_metadata_2025 huggingface dataset:
Simple and Efficient Aqueous Process for Nanostructured Fibrous TiO2 Regulated by Linear Polyethyleneimine Aggregates
Authors: Zhu Pei‐Xin , Jin Ren‐Hua
Published: December 2009

In this paper, we report a simple and smart biomimetic process for constructing TiO2 nanofibers in aqueous system and its derivatives with Pt nanoparticles uniformly embedded inside. It was found that regularly structured TiO2‐LPEI hybrids with fibrous networks could be easily produced when linear polyethyleneimine (LPEI) aggregates were used as a regulator in the hydrolytic condensation of water‐soluble titanium bislactates (TiLact). In the XRD patterns of the as‐prepared TiO2‐LPEI hybrids, a strong peak appeared at a low diffraction angle of about 4°, which indicated the formation of regularly layered domains consisting of TiO2 and LPEI residues in the fibrous hybrids. TEM observations showed that in the as‐prepared TiO2‐LPEI hybrids very tiny crystallites less than 3 nm in size were closely packed to each other, whereas the crystalline domains increased to 10 nm after the hybrids were calcined at 500 °C. Raman spectroscopy measurement confirmed the existence of anatase phase in the as‐prepared hybrids. Simply mixing the TiO2‐LPEI hybrids with an aqueous solution of PtCl42– spontaneously resulted in the formation of Pt nanoparticles embedded in the TiO2‐LPEI fibers. TEM images revealed that the Pt nanoparticles homogeneously distributed in the TiO2‐LPEI hybrids without any damage to their fibrous morphologies. A typical photocatalysis evaluation revealed that under visible‐light irradiation the Pt‐embedded TiO2 fibers exhibited two times higher activity in the photodecomposition of methylene blue than that of the pure TiO2 fibers.
Synthesis and Photophysical Properties of Copper(I) Complexes Obtained from 1,10‐Phenanthroline Ligands with Increasingly Bulky 2,9‐Substituents
Authors: Accorsi Gianluca , Armaroli Nicola , Duhayon Carine , Saquet Alix , Delavaux‐Nicot Béatrice , Welter Richard , Moudam Omar , Holler Michel , Nierengarten Jean‐François
Published: December 2009

In this paper, we describe the synthesis and the electronic properties of a series of [Cu(NN)2]+ systems. The NN ligands investigated are 2,9‐bis[(tert‐butyldimethylsilyloxy)methyl]‐1,10‐phenanthroline (1), 2,9‐bis[(triisopropylsilyloxy)methyl]‐1,10‐phenanthroline (2), 2,9‐bis[(tert‐butyldiphenylsilylmoxy)ethyl]‐1,10‐phenanthroline (3), 2,9‐bis[2,6‐bis(benzyloxy)phenethyl]‐1,10‐phenanthroline (4) and 2‐(1,3‐diphenylpropan‐2‐yl)‐9‐phenethyl‐1,10‐phenanthroline (5). The electrochemical properties and the ground state electronic absorption spectra of Cu(1)2–Cu(5)2 are in line with the classical behaviour of such [Cu(NN)2]+ derivatives. Whereas all the compounds exhibit MLCT luminescence centered around 630–650 nm, the emission quantum yields and the lifetimes are dramatically different as a function of stereoelectronic effects and/or the possibility of internal exciplex quenching when oxygen‐containing functional groups are attached to the phenanthroline ligands.
Synthesis and Photophysical Properties of Pyrene‐Based Light‐Emitting Monomers: Highly Pure‐Blue‐Fluorescent, Cruciform‐Shaped Architectures
Authors: Hu Jian‐yong , Era Masanao , Elsegood Mark R. J. , Yamato Takehiko
Published: December 2009

A new series of pyrene‐based, pure‐blue, fluorescent, stable monomers, namely 2,7‐di‐tert‐butyl‐4,5,9,10‐tetrakis(p‐R‐phenylethynyl)pyrenes, have been successfully synthesised by Pd/Cu‐catalysed Sonogashira coupling in excellent yield. The cruciform‐shaped, π‐conjugated structures were fully characterised by1H/13C NMR and IR spectroscopy, mass spectrometry and elemental analysis. As revealed from single‐crystal X‐ray analysis, there is a herringbone pattern between stacked columns, but the π‐π stacking distance of adjacent pyrene units was not especially short at about 5.82 Å due to the introduction of the two bulkytBu groups in the pyrene rings at the 2‐ and 7‐positions. The photophysical properties of these monomers were carefully examined in different organic solvents, and these data strongly indicate their promising application as blue‐emitting materials in organic light‐emitting diodes (OLEDs).
Fluoride‐Triggered Domino Reactions Involving Ammonium Acetylides and Carbonyl Compounds
Authors: Tejedor David , López‐Tosco Sara , Méndez‐Abt Gabriela , García‐Tellado Fernando
Published: December 2009

We describe the use of tetrabutylammonium fluoride as a basic trigger for reactions capable of generating structurally diverse products from methyl propiolate and carbonyl derivatives. The processes are based on either chemodifferentiating multicomponent ABB′ three‐component reactions or bimolecular domino reactions, and they operate through three different and well‐defined autocatalytic cycles. These catalytic cycles share a common property: they are launched by the acid–base reaction of fluoride ions to give catalytic amounts of acetylide or enolate salts, but they are maintained by the autocatalytic generation of these salts.
Exploring quality of life in the eating disorders
Authors: Bamford Bryony , Sly Richard
Published: December 2009

Objective

The present study aimed to investigate the impact of Body Mass Index (BMI), duration of illness and severity of illness on quality of life within a sample of individuals in treatment for an eating disorder. In addition this study explored differences in specific areas of quality of life (Psychological, Physical/Cognitive, Work/School and Financial) according to specific eating disorder diagnoses.

Method

Participants (N = 156) were adults currently receiving treatment for an eating disorder. Eating disorder symptomatology and quality of life were assessed using self‐report questionnaires. BMI, duration of illness and eating disorder diagnosis was obtained during a clinical interview.

Results

Severity of the eating disorder and BMI were predictors of low quality of life. Duration of illness, contrary to clinical expectations was not a significant predictor of poor quality of life. In terms of differences across diagnostic groups, individuals with a diagnosis of anorexia nervosa in this sample were found to have lower psychological and physical/cognitive quality of life than those with an EDNOS or BN diagnoses. Copyright © 2009 John Wiley & Sons, Ltd and Eating Disorders Association.
Estimating overnight de facto population by forecasting symptomatic variables: an integrated framework
Authors: Rigall‐I‐Torrent Ricard
Published: December 2009

In spite of the importance that measurements of temporary (de facto) populations have for public sector planning of services and infrastructures and for private firms' location purposes, no well‐established framework exists in the literature showing how to systematically perform such estimates. As a first step to overcoming the conceptual and practical difficulties surrounding the estimation of de facto population, this paper relies on forecasting symptomatic variables to integrate existing direct and indirect methods into a unified theoretical framework for estimating overnight residents. Copyright © 2009 John Wiley & Sons, Ltd.
On the association between IPO underpricing and reversal and Taiwan's regulatory reforms for mandatory forecasts
Authors: Chin Chen‐Lung , Lin Hsiou‐Wei William , Syu Yir‐Jung Emily
Published: December 2009

The unique institutions in Taiwan may add to our understanding of the effect of initial public offering (IPO) firm disclosures. Consistent with the notion of market mispricing, most of Taiwan's IPOs were with consecutive up‐limit hits followed by substantial price reversals. In this study, we decompose IPO underpricing into two components: pure underpricing and subsequent reversal, exploring the impact of the 1991 mandate that IPO firms should include their management forecasts in the prospectuses on these two anomaly measures. Our results support the notion that disclosure regulations ameliorate investors' mispricing the stocks. First, pure underpricing and reversal are significantly less (more) pronounced for post‐mandate (pre‐mandate) IPO stocks. In contrast, consistent with the cheap talk hypothesis, the pre‐mandate voluntary forecasters (non‐forecasters) appear to be more (less) underpriced. Second, the duration of underpricing for the post‐mandate (pre‐mandate) IPOs appears to be shorter (longer). Nevertheless, underpricing lasted relatively longer (shorter) for the pre‐mandate IPOs with (with no) voluntary disclosures. Copyright © 2009 John Wiley & Sons, Ltd.
The neural correlates of sex differences in emotional reactivity and emotion regulation
Authors: Domes Gregor , Schulze Lars , Böttger Moritz , Grossmann Annette , Hauenstein Karlheinz , Wirtz Petra H. , Heinrichs Markus , Herpertz Sabine C.
Published: December 2009

Sex differences in emotional responding have been repeatedly postulated but less consistently shown in empirical studies. Because emotional reactions are modulated by cognitive appraisal, sex differences in emotional responding might depend on differences in emotion regulation. In this study, we investigated sex differences in emotional reactivity and emotion regulation using a delayed cognitive reappraisal paradigm and measured whole‐brain BOLD signal in 17 men and 16 women. During fMRI, participants were instructed to increase, decrease, or maintain their emotional reactions evoked by negative pictures in terms of cognitive reappraisal. We analyzed BOLD responses to aversive compared to neutral pictures in the initial viewing phase and the effect of cognitive reappraisal in the subsequent regulation phase. Women showed enhanced amygdala responding to aversive stimuli in the initial viewing phase, together with increased activity in small clusters within the prefrontal cortex and the temporal cortex. During cognitively decreasing emotional reactions, women recruited parts of the orbitofrontal cortex, the anterior cingulate, and the dorsolateral prefrontal cortex to a lesser extent than men, while there was no sex effect on amygdala activity. In contrast, compared to women, men showed an increased recruitment of regulatory cortical areas during cognitively increasing initial emotional reactions, which was associated with an increase in amygdala activity. Clinical implications of these findings are discussed. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Oscillatory response function: Towards a parametric model of rhythmic brain activity
Authors: Ramkumar Pavan , Parkkonen Lauri , Hari Riitta
Published: December 2009

Rhythmic brain activity, measured by magnetoencephalography (MEG), is modulated during stimulation and task performance. Here, we introduce an oscillatory response function (ORF) to predict the dynamic suppression–rebound modulation of brain rhythms during a stimulus sequence. We derived a class of parametric models for the ORF in a generalized convolution framework. The model parameters were estimated from MEG data acquired from 10 subjects during bilateral tactile stimulation of fingers (stimulus rates of 4 Hz and 10 Hz in blocks of 0.5, 1, 2, and 4 s). The envelopes of the 17–23 Hz rhythmic activity, computed for sensors above the rolandic region, correlated 25%–43% better with the envelopes predicted by the models than by the stimulus time course (boxcar). A linear model with separate convolution kernels for onset and offset responses gave the best prediction. We studied the generalizability of this model with data from 5 different subjects during a separate bilateral tactile sequence by first identifying neural sources of the 17–23 Hz activity using cortically constrained minimum norm estimates. Both the model and the boxcar predicted strongest modulation in the primary motor cortex. For short‐duration stimulus blocks, the model predicted the envelope of the cortical currents 20% better than the boxcar did. These results suggest that ORFs could concisely describe brain rhythms during different stimuli, tasks, and pathologies. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Modulation of hyaluronan production by CD44 positive glioma cells
Authors: Wiranowska Marzenna , Ladd Sharron , Moscinski Lynn C. , Hill Bobbye , Haller Ed , Mikecz Katalin , Plaas Anna
Published: December 2009

This study examines the functional relationship between glioma cell production of hyaluronan (HA), known to play a role in glioma invasion, expression of its CD44 receptor, and glioma cell viability. Production of HA by CD44 positive mouse G26 and human U373 glioma cell lines was evaluated and compared to that of a CD44 positive mouse fibroblast‐like L929 cell line. We found that both G26 and U373 MG glioma cells, but not L929 fibroblast‐like cells, synthesized HA. The synthesis of HA by glioma cells was found during the proliferative phase as well as post‐confluency, as detected by fluorophore‐assisted carbohydrate electrophoresis. Eighty to ninety percent of the HA synthesized was secreted into the medium and 10–20% remained associated with the cells. To examine a possible mechanistic link between the CD44‐HA interaction and endogenous HA production, glioma cells were treated with either anti‐CD44 antibodies (clones KM201 or IM7) or HA oligosaccharides (hexamer oligoHA‐6 or decamer oligoHA‐10). We found that oligoHA‐10, which was previously shown to compete effectively with the CD44‐HA interaction, enhanced glioma HA synthesis by approximately 1.5‐fold, without affecting cell viability. IM7 treatment of human U373 glioma cells resulted in over 50% decrease of HA production, which was associated with changes in cell size and apoptosis. Taken together, these data show that CD44 specific ligands, such as the IM7 antibody or oligoHA‐10 could down‐regulate or up‐regulate glioma HA production, respectively. Our results suggest that interference with CD44/HA may lead to the discovery and development of new treatment modalities for glioma.
Loss of imprinting and marked gene elevation are 2 forms of aberrant IGF2 expression in colorectal cancer
Authors: Cheng Yu‐Wei , Idrees Kamran , Shattock Richard , Khan Sajid A. , Zeng Zhaoshi , Brennan Cameron W. , Paty Philip , Barany Francis
Published: December 2009

Loss of imprinting (LOI) of insulin‐like growth factor 2 (IGF2) is a common event in many cancers and typically activates the maternally silenced allele. The resulting biallelic IGF2 expression correlates strongly with the hypomethylation of a differentially methylated region (DMR) near its promoter. It has also been shown that IGF2 undergoes overexpression in human malignancies; nevertheless, this phenomenon and its link to aberrant DMR methylation have not been reported in colorectal cancer (CRC). The aim of this study was to determine the relationship between IGF2 LOI, overexpression and DMR hypomethylation in CRC. By analyzing IGF2 and H19 methylation in 97 primary CRC and 64 matched normal colorectal tissues, we have shown a significant correlation between IGF2 LOI and DMR hypomethylation of IGF2 and H19. Additionally, when analyzing Affymetrix expression data of 167 primary CRC tumors and 32 normal tissues, 15% of tumors showed marked IGF2 elevation. We further investigated if substantially elevated IGF2 levels were linked to IGF2 or H19 hypomethylation, but found no significant correlation. However, we demonstrated that noticeable IGF2 overexpression, rather than LOI, negatively correlated with CRC microsatellite instability. These observations indicate that IGF2 expression, particularly when transcribed at significantly high levels, is a result of mechanisms unrelated to LOI. Our results suggest that IGF2 participates in CRC tumorigenesis through 2 different forms of aberrant gene expression.
Chemo‐radiotherapy for advanced non‐small cell lung cancer: concurrent or sequential? It's no longer the question: a systematic review
Authors: Liang Hui‐Ying , Zhou Hao , Li Xue‐Lian , Yin Zhi‐Hua , Guan Peng , Zhou Bao‐Sen
Published: December 2009

There has been conflicting evidence concerning the best sequence of radiotherapy (RT) and chemotherapy (CT) for advanced non‐small‐cell‐lung‐cancer (NSCLC). To investigate whether current clinical trials can clarify this schedule and offer further bases for clinical decision making, we performed a systematic review of 11 trials (2,043 patients; concurrent–1,019, sequential–1,024) that compared concurrent RT‐CT with sequential arm in advanced NSCLC patients. Primary end point was overall survival (OS). Pooled median ratios (MRs) and progression‐free‐survival ratios (FRs) for median survival and progression‐free survival (PFS) were calculated using the weighted sum of the log ratio of MR and FR of individual study. Pooled odds ratios (ORs) for the objective response rate, relapse control rate, and toxic events were calculated using the Mantel‐Haenszel estimate. Results confirmed that concurrent RT‐CT determined a statistically significant increase in median survival time (16.3 vs. 13.9 months; MR = 1.17,95%CI:1.09–1.26), response rate (64.0% vs. 56.3%; OR = 1.38,95%CI:1.10–1.72), and tumor‐relapse control (OR = 0.82,95%CI:0.69–0.97), though at the expense of increased hematological toxicity (neutropenia and thrombocytopenia) and non‐hematological toxicity (nausea/vomiting, stomatitis, and esophagitis). Similar results were obtained from the sensitivity analysis of all Phase‐III/trials designed to evaluate the primary end point of OS. Subgroup analysis revealed that concurrent strategy was mainly associated with improved loco‐regional control (OR = 0.68,95%CI:0.52–0.87). However, no difference in PFS is shown. While careful interpretation of our conclusions is required because of potential bias, the present study, to some extent, exhibits the superiority of the concurrent arm over the sequential in the treatment of advanced NSCLC. Further improvements will be obtained by optimizing the conditions for a concurrent regimen.
Cyclin B1 is a prognostic proliferation marker with a high reproducibility in a population‐based lymph node negative breast cancer cohort
Authors: Niméus‐Malmström E. , Koliadi A. , Ahlin C. , Holmqvist M. , Holmberg L. , Amini R.‐M. , Jirström K. , Wärnberg F. , Blomqvist C. , Fernö M. , Fjällskog M.‐L.
Published: December 2009

A large proportion of women with lymph node negative breast cancer do not benefit from chemotherapy. Proliferation markers have been shown to recognize patients at high risk for recurrence. The Ki67 protein has recently been included in the St Gallen guidelines. The authors investigated the prognostic importance of cyclin B1 in node negative breast cancer and included a study of reproducibility. In a population‐based case‐control study, 190 women who died from breast cancer were defined as cases and 190 women alive at the time for the corresponding case's death were defined as controls. Inclusion criteria were tumor size ≤50 mm, no lymph node metastases, and no adjuvant chemotherapy. Tumor tissue was immunostained for cyclin B1. Two investigators (EN‐M and AK) evaluated the staining independently by counting approximately 100, 200, 500, and 1000 cells. Cyclin B1 was statistically significantly associated to breast cancer death, in both uni‐ and multivariate analyses (adjusted for tumor size, age, and endocrine therapy), with odds ratios 2–3 for both investigators. The agreement between the two investigators was good to very good, regardless of the number of counted cells (kappa values between 0.74 and 0.82). Cyclin B1 is a prognostic factor for breast cancer death in a population‐based node negative patient cohort which can identify high‐risk patients with a good to very good reproducibility.
Nanotechnology‐based molecular photoacoustic and photothermal flow cytometry platform for in‐vivo detection and killing of circulating cancer stem cells
Authors: Galanzha Ekaterina I. , Kim Jin‐Woo , Zharov Vladimir P.
Published: December 2009

In‐vivo multicolor photoacoustic (PA) flow cytometry for ultrasensitive molecular detection of the CD44+ circulating tumor cells (CTCs) is demonstrated on a mouse model of human breast cancer. Targeting of CTCs with stem‐like phenotype, which are naturally shed from parent tumors, was performed with functionalized gold and magnetic nanoparticles. Results in vivo were verified in vitro with a multifunctional microscope, which integrates PA, photothermal (PT), fluorescent and transmission modules. Magnet‐induced clustering of magnetic nanoparticles in individual cells significantly amplified PT and PA signals. The novel noninvasive platform, which integrates multispectral PA detection and PT therapy with a potential for multiplex targeting of many cancer biomarkers using multicolor nanoparticles, may prospectively solve grand challenges in cancer research for diagnosis and purging of undetectable yet tumor‐initiating cells in circulation before they form metastasis. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An injection molding process for manufacturing highly porous and interconnected biodegradable polymer matrices for use as tissue engineering scaffolds
Authors: Kramschuster Adam , Turng Lih‐Sheng
Published: December 2009

In this research, injection molding was combined with a novel material combination, supercritical fluid processing, and particulate leaching techniques to produce highly porous and interconnected structures that have the potential to act as scaffolds for tissue engineering applications. The foamed structures, molded with polylactide (PLA) and polyvinyl alcohol (PVOH) with salt as the particulate, were processed without the aid of organic solvents, which can be detrimental to tissue growth. The pore size in the scaffolds is controlled by salt particulates and interconnectivity is achieved by the co‐continuous blending morphology of biodegradable PLA matrix with water‐soluble PVOH. Carbon dioxide (CO2) at the supercritical state is used to serve as a plasticizer, thereby imparting moldability of blends even with an ultra high salt particulate content, and allows the use of low processing temperatures, which are desirable for temperature‐sensitive biodegradable polymers. Interconnected pores of ∼200 μm in diameter and porosities of ∼75% are reported and discussed. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Evaluation of microhardness, surface roughness, and wear behavior of different types of resin composites polymerized with two different light sources
Authors: Topcu Fulya Toksoy , Erdemir Ugur , Sahinkesen Gunes , Yildiz Esra , Uslan Ibrahim , Acikel Cengizhan
Published: December 2009

The microhardness, surface roughness and wear resistance of different types of resin composites, polymerized by a Quartz Tungsten Halogen (QTH) or Light Emitting Diode (LED) light curing units (LCU) were evaluated in this in vitro study. Cylindrical blocks were prepared from composites (8 mm in diameter, and 2 mm in thickness) and polymerized by a LED or a QTH LCU. Vickers hardness was measured on the top and bottom surfaces of the specimens. Surface roughness was measured with a surface profilometer on the top of the specimens. For the wear test, specimens were tested in a conventional pin‐on‐disc tribology machine under 15 N loads. The statistical analyses were performed by one‐way analysis of variance (ANOVA) and t‐tests, including the Bonferroni correction. Nanocomposite material Clearfil Majesty™ Posterior showed the highest hardness values in all polymerization types at the top and bottom surfaces (p < 0.05). Microhybrid Clearfil™ APX and hybrid Quixfil™ composites demonstrated the greatest surface roughness. Wear resistance of Clearfil Majesty™ Posterior was found to be the highest among the other tested resin composites. The results indicated that Clearfil Majesty™ Posterior demonstrated higher microhardness, less surface roughness, and higher wear resistance when compared with the other tested materials for both polymerization types. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Modification of the diphenylamine assay for cell quantification in three‐dimensional biodegradable polymeric scaffolds
Authors: Pham Edward A. , Ho Won Jin , Kamei Daniel T. , Wu Benjamin M.
Published: December 2009

As three‐dimensional (3D) cell culture systems gain popularity in biomedical research, reliable assays for cell proliferation within 3D matrices become more important. Although many cell quantification techniques have been established for cells cultured on nondegradable plastic culture dishes and cells suspended in media, it is becoming increasingly clear that cell quantification after prolonged culture in 3D polymeric scaffolds imposes unique challenges because the added presence of polymeric materials may contribute to background signal via various mechanisms including autofluorescence, diffusion gradients, and sequestering effects. Thus, additional steps are required to ensure complete isolation of cells from the 3D scaffold. The diphenylamine assay isolates cellular DNA, degrades the polymeric matrix materials, and reacts with the DNA to yield a colorimetric response. Thus, we report here a practical modification of the diphenylamine assay and show that the assay quantifies cells in 3D polyester scaffolds reliably and reproducibly as long as the necessary amount of the acidic working reagent is present. Our study also demonstrates that the sensitivity of the assay can be optimized by controlling the dimensions of the sampling volume. Overall, the DPA assay offers an attractive solution for challenges associated with 3D cell quantification. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Macro‐alignment of electrospun fibers for vascular tissue engineering
Authors: Zhu Yabin , Cao Ye , Pan Jin , Liu Yuxin
Published: December 2009

Design of polymeric scaffolds with specific physical and biological properties is a key objective of tissue engineering research. Electrospinning generates loosely connected 3D porous mats simulating extra cellular matrix structure and therefore makes itself an excellent candidate for application in tissue engineering. Besides a high voltage generator and syringe pump, our electrospinning system was improved to add a programmable central controller which monitors system operation. The nozzles connected with syringe pump via silicon rubber tubing can move linearly with a step size of 0.1 μm or above while the mandrel collector rotates at a speed from 400 to 3000 revolutions per minute (rpm). Using this system, porous fiber sheets with fiber diameters ranging from 100 nm to several micrometers or meshes of macroscopically aligned fibers with diameter of ∼10 μm have been fabricated under proper processing conditions. After biocompatible fibrin coating, oriented polycaprolactone (PCL) fibers were found to enhance the shifting of human umbilical artery smooth muscle cells from synthetic to contractile phenotype, and to maintain biological function of human umbilical vein endothelial cells. We believe that our electrospinning system will facilitate scaffold fabrication for vessel tissue engineering. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Carboxymethylation of the fibrillar collagen with respect to formation of hydroxyapatite
Authors: Ehrlich Hermann , Hanke Thomas , Simon Paul , Born René , Fischer Christiane , Frolov Andrej , Langrock Tobias , Hoffmann Ralf , Schwarzenbolz Uwe , Henle Thomas , Bazhenov Vasily V. , Worch Hartmut
Published: December 2009

Control over crystal growth by acidic matrix macromolecules is an important process in the formation of many mineralized tissues. Highly acidic macromolecules are postulated intermediates in tissue mineralization, because they sequester many calcium ions and occur in high concentrations at mineralizing foci in distantly related organisms. A prerequisite for biomineralization is the ability of cations like calcium to bind to proteins and to result in concert with appropriate anions like phosphates or carbonates in composite materials with bone‐like properties. For this mineralization process the proteins have to be modified with respect to acidification. In this study we modified the protein collagen by carboxymethylation using glucuronic acid. Our experiments showed unambigously, that Nε‐carboxymethyllysine is the major product of the in vitro nonenzymatic glycation reaction between glucuronic acid and collagen. We hypothesized that the function of biomimetically carboxymethylated collagen is to increase the local concentration of corresponding ions so that a critical nucleus of ions can be formed, leading to the formation of the mineral. Thus, the self‐organization of HAP nanocrystals on and within collagen fibrils was intensified by carboxymethylation. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Diffusion bonding of mismatch dental alloys
Authors: Liu Honghua , Ni Jiahua , Wu Luhai , He Guo
Published: December 2009

The diffusion bonding of Ti‐6Al‐4V and Co‐Cr‐Mo dental alloys has been investigated in terms of the atoms diffusion, the microstructure evolution, and the bonding strength. The bonding performance reveals asymmetry diffusion profiles for both the Co and Cr in Ti‐6Al‐4V and the Ti in Co‐Cr‐Mo alloy. Their diffusion coefficients (Arrhenius relations) have been established based on the experiments. Co and Cr diffusion into Ti‐6Al‐4V leads to alpha → beta transformation and the intermetallics‐formation. Maximum bonding strength occurs at about 840°C. The bonding joint fails under the shear stress in the Ti‐6Al‐4V side near the bonding interface in brittle manner. The intermetallics in the diffusion layer together with the unbonded areas and other flaws in the bonding interface are responsible for the shear brittle fracture, which also weaken the bonding strength. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Expression analysis of epithelial cadherin and related proteins in IBH‐6 and IBH‐4 human breast cancer cell lines
Authors: Lapyckyj Lara , Castillo Lilian Fedra , Matos María Laura , Gabrielli Nieves María , Lüthy Isabel Alicia , Vazquez‐Levin Mónica Hebe
Published: December 2009

Epithelial cadherin (E‐cadherin) is a 120 kDa cell–cell adhesion molecule involved in the establishment of epithelial adherens junctions. It is connected to the actin cytoskeleton by adaptor proteins such as β‐catenin. Loss of E‐cadherin expression/function has been related to tumor progression and metastasis. Several molecules associated with down‐regulation of E‐cadherin have been described, within them neural cadherin, Twist and dysadherin. Human breast cancer cell lines IBH‐6 and IBH‐4 were developed from ductal primary tumors and show characteristic features of malignant epithelial cells. In this study expression of E‐cadherin and related proteins in IBH‐6 and IBH‐4 cell lines was evaluated. In IBH‐6 and IBH‐4 cell extracts, only an 89 kDa E‐cadherin form (Ecad89) was detected, which is truncated at the C‐terminus and is present at low levels. Moreover, no accumulation of the 86 kDa E‐cadherin ectodomain and of the 38 kDa CTF1 fragment was observed. IBH‐6 and IBH‐4 cells showed an intracellular scattered E‐cadherin localization. β‐catenin accompanied E‐cadherin localization, and actin stress fibers were identified in both cell types. E‐cadherin mRNA levels were remarkably low in IBH‐6 and IBH‐4 cells. The E‐cadherin mRNA and genomic sequence encoding exons 14–16 could not be amplified in either cell line. Neither the mRNA nor the protein of neural cadherin and dysadherin were detected. Up‐regulation of Twist mRNA was found in both cell lines. In conclusion, IBH‐6 and IBH‐4 breast cancer cells show down‐regulation of E‐cadherin expression with aberrant protein localization, and up‐regulation of Twist; these features can be related to their invasive/metastatic characteristics. J. Cell. Physiol. 222: 596–605, 2010. © 2009 Wiley‐Liss, Inc.
Inorganic polyphosphate inhibits an aspartic protease‐like activity in the eggs of Rhodnius prolixus (Stahl) and impairs yolk mobilization in vitro
Authors: Gomes F.M. , Oliveira D.M.P. , Motta L.S. , Ramos I.B. , Miranda K.M. , Machado E.A.
Published: December 2009

Inorganic polyphosphate (poly P) is a polymer of phosphate residues that has been shown to act as modulator of some vertebrate cathepsins. In the egg yolk granules of Rhodnius prolixus, a cathepsin D is the main protease involved in yolk mobilization and is dependent on an activation by acid phosphatases. In this study, we showed a possible role of poly P stored inside yolk granules on the inhibition of cathepsin D and arrest of yolk mobilization during early embryogenesis of these insects. Enzymatic assays detected poly P stores inside the eggs of R. prolixus. We observed that micromolar poly P concentrations inhibited cathepsin D proteolytic activity using both synthetic peptides and homogenates of egg yolk as substrates. Poly P was a substrate for Rhodnius acid phosphatase and also a strong competitive inhibitor of a pNPPase activity. Fusion events have been suggested as important steps towards acid phosphatase transport to yolk granules. We observed that poly P levels in those compartments were reduced after in vitro fusion assays and that the remaining poly P did not have the same cathepsin D inhibition activity after fusion. Our results are consistent with the hypothesis that poly P is a cathepsin D inhibitor and a substrate for acid phosphatase inside yolk granules. It is possible that, once activated, acid phosphatase might degrade poly P, allowing cathepsin D to initiate yolk proteolysis. We, therefore, suggest that degradation of poly P might represent a new step toward yolk mobilization during embryogenesis of R. prolixus. J. Cell. Physiol. 222: 606–611, 2010. © 2009 Wiley‐Liss, Inc.
Hypoxic enlarged mitochondria protect cancer cells from apoptotic stimuli
Authors: Chiche Johanna , Rouleau Matthieu , Gounon Pierre , Brahimi‐Horn M. Christiane , Pouysségur Jacques , Mazure Nathalie M.
Published: December 2009

It is well established that cells exposed to the limiting oxygen microenvironment (hypoxia) of tumors acquire resistance to chemotherapy, through mechanisms not fully understood. We noted that a large number of cell lines showed protection from apoptotic stimuli, staurosporine, or etoposide, when exposed to long‐term hypoxia (72 h). In addition, these cells had unusual enlarged mitochondria that were induced in a HIF‐1‐dependent manner. Enlarged mitochondria were functional as they conserved their transmembrane potential and ATP production. Here we reveal that mitochondria of hypoxia‐induced chemotherapy‐resistant cells undergo a HIF‐1‐dependent and mitofusin‐1‐mediated change in morphology from a tubular network to an enlarged phenotype. An imbalance in mitochondrial fusion/fission occurs since silencing of not only the mitochondrial fusion protein mitofusin 1 but also BNIP3 and BNIP3L, two mitochondrial HIF‐targeted genes, reestablished a tubular morphology. Hypoxic cells were insensitive to staurosporine‐ and etoposide‐induced cell death, but the silencing of mitofusin, BNIP3, and BNIP3L restored sensitivity. Our results demonstrate that some cancer cells have developed yet another way to evade apoptosis in hypoxia, by inducing mitochondrial fusion and targeting BNIP3 and BNIP3L to mitochondrial membranes, thereby giving these cells a selective growth advantage. J. Cell. Physiol. 222: 648–657, 2010. © 2009 Wiley‐Liss, Inc.
Selection of bead‐displayed, PNA‐encoded chemicals
Authors: Gassman Natalie R. , Nelli J. Patrick , Dutta Samrat , Kuhn Adam , Bonin Keith , Pianowski Zbigniew , Winssinger Nicolas , Guthold Martin , Macosko Jed C.
Published: December 2009

The lack of efficient identification and isolation methods for specific molecular binders has fundamentally limited drug discovery. Here, we have developed a method to select peptide nucleic acid (PNA) encoded molecules with specific functional properties from combinatorially generated libraries. This method consists of three essential stages: (1) creation of a Lab‐on‐Bead™ library, a one‐bead, one‐sequence library that, in turn, displays a library of candidate molecules, (2) fluorescence microscopy‐aided identification of single target‐bound beads and the extraction – wet or dry – of these beads and their attached candidate molecules by a micropipette manipulator, and (3) identification of the target‐binding candidate molecules via amplification and sequencing. This novel integration of techniques harnesses the sensitivity of DNA detection methods and the multiplexed and miniaturized nature of molecule screening to efficiently select and identify target‐binding molecules from large nucleic acid encoded chemical libraries. Beyond its potential to accelerate assays currently used for the discovery of new drug candidates, its simple bead‐based design allows for easy screening over a variety of prepared surfaces that can extend this technique's application to the discovery of diagnostic reagents and disease markers. Copyright © 2009 John Wiley & Sons, Ltd.
The influence of age on the associations between HR practices and both affective commitment and job satisfaction: A meta‐analysis
Authors: Kooij Dorien T. A. M. , Jansen Paul G. W. , Dikkers Josje S. E. , De Lange Annet H.
Published: December 2009

Research on the association between high commitment Human Resource (HR) practices and work‐related outcomes at the individual level rarely focuses on age differences. To fill this knowledge gap, a meta‐analysis has been conducted to examine how the relationships between the availability of high commitment HR practices, as perceived by employees, and affective commitment and job satisfaction change with age. Drawing on Selection, Optimization, and Compensation (SOC) theory and on Regulatory Focus theory, we identify a bundle of maintenance HR practices and a bundle of development HR practices, and hypothesize that the association between maintenance HR practices and work‐related attitudes strengthens with age, and that the association between development HR practices and work‐related attitudes weakens with age. Our meta‐analysis of 83 studies reveals that, in line with social exchange and signaling theories, employees' perceptions of HR practices are positively related to their work‐related attitudes, and that calendar age influences this relationship largely as expected. These results are discussed in light of the above mentioned theories. Copyright © 2009 John Wiley & Sons, Ltd.
Surface Segregation Assessment In Poly(ε‐caprolactone)‐poly(ethylene glycol) Multiblock Copolymer Films
Authors: Cometa Stefania , Chiellini Federica , Bartolozzi Irene , Chiellini Emo , De Giglio Elvira , Sabbatini Luigia
Published: December 2009

The ability to predict the in vivo performance of multiblock‐copolymer‐based biomaterials is crucial for their applicability in the biomedical field. In this work, XPS analysis of PCL‐PEG copolymers was carried out, as well as morphological and wettability evaluations by SEM and CA measurements, respectively. XPS analysis on films equilibrated in PBS demonstrated a further enrichment in the PEG component on the surface. Copolymer films obtained by casting using different solvents showed a dependence in segregation according to the solvent employed. Cell adhesion tests demonstrated the importance of copolymer segregation and rearrangement in a wet environment, with a dependence of these phenomena on the copolymer molecular weight.

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Modification of EPDM with Alkylphenol Polysulfide for Use in Tire Sidewalls, 1 – Mechanical Properties
Authors: Zhang Hongmei , Datta Rabin N. , Talma Auke G. , Noordermeer Jacques W. M.
Published: December 2009

APPS has been used to modify EPDM in order to solve the cure incompatibility and heterogeneous filler distribution of NR/BR/EPDM blends for tire sidewall applications. The physical properties of the NR/BR/APPS‐EPDM blends are compared with an NR/BR/EPDM blend and a conventional NR/BR tire sidewall. It is demonstrated that the application of APPS‐EPDM leads to a significant improvement of the tensile properties, tear strength, and fatigue properties. The properties of the NR/BR/APPS‐EPDM blends are equivalent or even superior to those of conventional NR/BR tire sidewall compounds. The dynamic viscoelastic properties of the NR/BR/APPS‐EPDM blends are not quite comparable with the conventional NR/BR sidewall blend, but still greatly improved, compared to using virgin EPDM.

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Modification of EPDM with Alkylphenol Polysulfide for Use in Tire Sidewalls, 2 – Mechanistic and Morphological Characterizations
Authors: Zhang Hongmei , Datta Rabin N. , Talma Auke G. , Lu Kangbo , Loos Joachim , Noordermeer Jacques W. M.
Published: December 2009

It has been shown that the mechanical properties of NR/BR/EPDM blends can be improved by using APPS as a modifier. In this paper, it is demonstrated that modification of EPDM with APPS takes place and saturation occurs when the APPS amount reaches 5 wt.‐%. It is shown that the rubber/carbon black affinity improves by using APPS‐grafted EPDM in the blend. TEM and STEM images clearly show that the NR/BR/APPS‐EPDM blend contains a significantly higher content of homogeneous rubber phase than the unmodified NR/BR/EPDM blend. The much better distribution of the carbon black in the APPS‐EPDM phase is considered the main reason for the improvement in properties of the blend.

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Reconstruction of anterior through and through oromandibular defects following oncological resections
Authors: Bianchi Bernardo , Ferri Andrea , Ferrari Silvano , Copelli Chiara , Boni Pietro , Sesenna Enrico
Published: December 2009

Background:

Resections of oromandibular squamous cell carcinoma involving anterior mandible, floor of the mouth, and the skin, lead to composite oromandibular defects that can be approached in several ways depending on the extension of the bone defect, of the soft tissue and cutaneous resection, the patient's general status, and the prognosis.

Methods:

A retrospective evaluation of 27 patients has been performed. The techniques described included single osseous or soft tissues free flap reconstruction, two free flaps or free and locoregional flap association.

Results:

Postoperative follow‐up ranged from 12 to 120 months. Final results were evaluated with regards to deglutition, speech, oral competence, and esthetic outcome.

Conclusion:

Reconstruction of the anterior mandible is strongly indicated whenever possible. When the defect involves the tongue, the best results are provided by the association of two free flaps. Finally, the association of free and locoregional flaps ia a good option for external coverage reconstruction. © 2009 Wiley‐Liss, Inc. Microsurgery, 2010.
A stress‐return algorithm for nonlocal constitutive models of softening materials
Authors: Nguyen Giang D. , Einav Itai
Published: December 2009

We develop a fully implicit stress‐return algorithm for a wide range of nonlocal inelastic models (of integral type) with coupling among integration points. Two examples of nonlocal models are presented, which combine plasticity with either damage or breakage. Using these models, we emphasize the need for a versatile integration scheme for nonlocal incremental constitutive equations. Furthermore, these models are used to demonstrate the importance of adequately selecting the way constitutive equations for softening materials are regularized. The stress update process requires the construction of a nonlocal constitutive matrix: we highlight and take advantage of its sparsity. Numerical solutions to relevant structural and geomechanical boundary value problems are used to demonstrate the performance of the proposed approach. Copyright © 2009 John Wiley & Sons, Ltd.
Fabrication of poly(acrylamide) hydrogels with gradient crosslinking degree via photoinitiation of thick polymer system
Authors: Li Shurun , Yang Wantai
Published: December 2009

In this paper, we report on the synthesis of poly(acrylamide) (PAM) hydrogels by photoinitiation with a thick system. The hydrogels exhibited gradient crosslinking density along the light path. Thermogravimetric analyses (TGA) proved the same effects. We investigated some factors affecting the swelling ratio of the hydrogels such as crosslinking agent concentration, photoinitiator concentration, and monomer concentration. The as‐prepared hydrogels might have some potential applications in drug delivery systems and other function materials. Copyright © 2009 John Wiley & Sons, Ltd.
An investigation into synergistic effects of rare earth oxides on intumescent flame retardancy of polypropylene/poly (octylene‐co‐ethylene) blends
Authors: Ren Qiang , Wan Chaoying , Zhang Yong , Li Jian
Published: December 2009

Synergistic effects of two kinds of rare earth oxides (REOs), neodymium oxide (Nd2O3) or lanthanum oxide (La2O3) on the intumescent flame retardancy of thermoplastic polyolefin (TPO) made by polypropylene/poly (octylene‐co‐ethylene) blends were investigated systemically by various methods. The limiting oxygen index (LOI) of flame retardant TPO (FRTPO) filled by 30 wt% intumescent flame retardants (IFR) composed of ammonium polyphosphate (APP) and pentaerythritol (PER) has been increased from 30 to 32.5 and 33.5 when 0.5 wt% of IFR was substituted by La2O3 and Nd2O3, respectively. Cone calorimetry tests also reveal the existence of synergistic effects. Thermalgravimetric analyses (TGA) demonstrate that the presence of REOs promotes the esterification and carbonization process in low‐temperature range while enhances the thermal stability of IFR and FRTPO in high‐temperature range. X‐ray diffraction (XRD) reveals that the interaction of Nd2O3 with IFR results in the formation of neodymium phosphate (NdP5O14) with high‐thermal stability. Thermal scanning rheological tests show that the presence of REOs increases complex viscosity of FRTPO in the temperature range of 190∼300°C so as to suppress melt dripping but decreases the complex viscosity and increases the loss factors tan δ in temperature range of 300∼400°C to make the carbonaceous strucuture more flexible and viscous to resist stress, expand better and keep intact. Copyright © 2009 John Wiley & Sons, Ltd.
Lipophilic constituents from aerial and root parts of Mercurialis perennis L.
Authors: Lorenz Peter , Hradecky Marc , Berger Melanie , Bertrams Julia , Meyer Ulrich , Stintzing Florian C.
Published: December 2009

Introduction – Dog's mercury (Mercurialis perennis L.) is a perennial herb used in remedies for medicinal purposes. The plant is supposed to contain potentially active substances but its constituents have only been rarely studied.

Objective – Detailed studies on the phytochemical composition are of great interest to broaden the knowledge on the chemotaxonomy and pharmacognosy of M. perennis.

Methodology – Chloroform and hexane extracts from roots and aerial parts were investigated using GC/MS and LC/MS.

Results – The whole plant exhihited a broad spectrum of structurally diverse constituents, mainly alkaloids, terpenes, sterols and simple aromatic compounds. Closer inspection of the piperidine alkaloid hermidin revealed its inherent instability towards air oxygen. To obtain quantitative data on these alkaloids the synthesis of the more stable reference compound 4‐methoxy‐1‐methylpyridine‐2,6(1H,3H)‐dione (MMPD) was required. In this study, MMPD was detected for the first time as a genuine compound in Mercurialis. Hermidine quinone and hermidin dimers originating from hermidin via a free anionic radical reaction were also confirmed by GC/MS. Moreover, volatile compounds such as benzylalcohol, 2‐phenylethanol, 4‐methoxy‐ and 3,4‐dimethoxyphenol, (−)‐cis‐ and (+)‐trans‐myrtanol, (−)‐cis‐myrtanal as well as squalene were predominantely present in Mercurialis roots. In contrast, aerial parts mainly contained phytol derivatives, sterols and tocopherols. By changing solvent polarity, lipid and wax‐containing fractions were obtained. LC/MS‐studies on hexane extracts showed the presence of several mixed triglycerides constituted by linolenic, linoleic, oleic, stearic and palmitic acids, as well as lutein, carotenes and pheophytins.

Conclusions – The phytochemical data presented complement our knowledge on the rarely studied plant M. perennis and may broaden its use in future phytotherapy. Copyright © 2009 John Wiley & Sons, Ltd.