bluuebunny/crossref_metadata_2025 huggingface dataset:
Generation of a germ cell‐specific mouse transgenic cherry reporter, Sohlh1‐mCherryFlag
Authors: Suzuki Hitomi , Dann Christina Tenenhaus , Rajkovic Aleksandar
Published: September 2012

Visualization of differentiating germ cells is critical to understanding the formation of primordial follicles in the ovary, and the commitment of spermatogonial stem cells to differentiation. We engineered and generated a BAC transgenic mouse line, Sohlh1‐mCherryFlag (S1CF), under the direction of the native Sohlh1 promoter. Sohlh1 is a germ cell‐specific gene that encodes the basic helix‐loop‐helix (bHLH) transcriptional regulator that is essential in oogenesis and spermatogenesis. Sohlh1 expression is unique, and is limited to perinatal and early follicle oocytes and differentiating spermatogonia. The Sohlh1‐mCherryFlag transgene was engineered to fuse SOHLH1 to the red fluorescent protein CHERRY with 3‐tandem‐FLAG tags. S1CF animals fluoresce specifically in the oocytes of perinatal ovaries and small follicles in adult ovaries, as well as in spermatogonia, a pattern that is similar to endogenous SOHLH1. Moreover, S1CF rescued germ cell loss and infertility in both male and female Sohlh1−/− animals. The FLAG‐tag on S1CF was effective for immunostaining and immunoprecipitation. The Sohlh1‐mCherryFlag transgenic mouse provides a unique model to study early germ cell differentiation, as well as in vivo imaging and purification of differentiating germ cells. genesis 51:50–58, 2013. © 2012 Wiley Periodicals, Inc.
Male pheromone polymorphism and reproductive isolation in populations of Drosophila simulans
Authors: Bontonou Gwénaëlle , Denis Béatrice , Wicker‐Thomas Claude
Published: September 2012

The dominant cuticular hydrocarbons (HC) in Drosophila simulans are 7‐tricosene (7‐T) and 7‐pentacosene (7‐P). The 7‐T is the major HC in East Africa and in other continents. In West Africa, D. simulans is very rare and displays 7‐P as the major compound. We studied three D. simulans strains from Egypt (Eg), Sao‐Tome (ST), and Cameroon (Cam), with 7‐T, intermediary or 7‐P phenotypes. HC profiles of ST and Cam female differed slightly from corresponding male profiles; females had more 7‐T and less 7‐P. Varying temperature affected all HCs (even those with 27 and 29 carbons)‐not just 7‐T and 7‐P; there was no clear relationship between HC phenotype and resistance to desiccation. We report reproductive isolation between Eg and ST and Eg and Cam (but not between ST and Cam), which is due to Eg and Cam female preferences for their own males. In conclusion, our findings do support divergence of D. simulans populations from West Africa for both pheromonal profile and mating preference.
Lipocalin‐2 ameliorates granulocyte functionality
Authors: Schroll Andrea , Eller Kathrin , Feistritzer Clemens , Nairz Manfred , Sonnweber Thomas , Moser Patrizia A. , Rosenkranz Alexander R. , Theurl Igor , Weiss Guenter
Published: September 2012

Attraction of neutrophils to sites of infection or tissue injury is an essential prerequisite for an efficient innate immune response. Herein, we provide novel evidence that the antimicrobial protein, neutrophil gelatinase associated lipocalin (24p3 or lipocalin‐2, Lcn2) is a central regulator of this process. Lcn2 is produced by several cell types but high amounts are released by neutrophils. Using human and murine neutrophils, we found that the addition of recombinant Lcn2 significantly stimulated their migration, which was independent of IL‐8/keratinocyte chemokine formation. Mechanistically, this could be traced back to Lcn2‐mediated changes of Erk1/2 signaling. Accordingly, the i.p. injection of Lcn2 into C57BL/6 mice stimulated the mobilization of neutrophils while we found a significantly reduced neutrophil chemotactic activity of cells obtained from Lcn2 KO mice. This observation transmitted to a reduced accumulation of neutrophils in intra‐dermal lesions infected with Salmonella typhimurium in Lcn2 KO mice as compared to WT mice. This was not only due to a reduced chemotaxis but also to an impaired cellular adhesion of neutrophils in the absence of Lcn2. We herein describe a novel role of Lcn2 as an important paracrine chemoattractant and an indispensable factor for neutrophil function in inflammation.
Distinctive features of classic and nonclassic (Th17 derived) human Th1 cells
Authors: Maggi Laura , Santarlasci Veronica , Capone Manuela , Rossi Maria Caterina , Querci Valentina , Mazzoni Alessio , Cimaz Rolando , De Palma Raffaele , Liotta Francesco , Maggi Enrico , Romagnani Sergio , Cosmi Lorenzo , Annunziato Francesco
Published: September 2012

T helper17 (Th17) lymphocytes represent a third arm of the CD4+ T‐cell effector responses, in addition to Th1 and Th2 cells. Th17 cells have been found to exhibit high plasticity because they rapidly shift into the Th1 phenotype in inflammatory sites. In humans, Th1 cells derived from Th17 cells express CD161, whereas classic Th1 cells do not; these Th17‐derived Th1 cells have been termed nonclassic Th1 cells. In this study, we examined similarities and differences between classic and nonclassic human Th1 cells by assessing a panel of T‐cell clones, as well as CD161+ or CD161− CD4+ T cells derived ex vivo from the circulation of healthy subjects or the synovial fluid of patients with juvenile idiopathic arthritis. The results show that nonclassic Th1 cells can be identified based on CD161 expression, as well as the consistent expression of retinoic acid orphan receptor C, IL‐17 receptor E, CCR6, and IL‐4‐induced gene 1, which are all virtually absent in classic Th1 cells. The possibility to distinguish these two‐cell subsets by using such a panel of markers may allow the opportunity to better establish the respective pathogenic roles of classic and nonclassic (Th17 derived) Th1 cells in different chronic inflammatory disorders.
Growth and Chemical Stability of Copper Nanostructures on Cellulosic Fibers
Authors: Pinto Ricardo J. B. , Neves Márcia C. , Neto Carlos Pascoal , Trindade Tito
Published: September 2012

The design of paper products based on copper nanoparticles (NPs) is a challenge because of the intrinsic propensity of Cu to oxidize in contact with air. Here, a comparative study on the growth and chemical stability of Cu NPs in vegetable and bacterial cellulose is described for the first time. Furthermore, comparative studies were performed by using inorganic fillers of distinct dimensionality, Cu NPs and Cu nanowires (NWs), in both types of cellulose. Cu NWs were found to be more resistant to oxidation caused by prolonged air exposure than the Cu NPs. Notably, the cellulosic matrices behave differently for the growth or adsorption of the Cu nanofillers; bacterial cellulose fibers are the most efficient substrate to delay surface oxidation. The data support a role for bacterial cellulose in limiting the oxidation of Cu nanostructures that have been grown or blended in this type of matrix, hence opening up new perspectives for the development of electronic paper technologies that incorporate copper nanophases.
Water‐Soluble (Pterin)rhenium(I) Complex: Synthesis, Structural Characterization, and Two Reversible Protonation–Deprotonation Behavior in Aqueous Solutions
Authors: Ragone Fabricio , Ruiz Gustavo T. , Piro Oscar E. , Echeverría Gustavo A. , Cabrerizo Franco M. , Petroselli Gabriela , Erra‐Balsells Rosa , Hiraoka Kenzo , García Einschlag Fernando S. , Wolcan Ezequiel
Published: September 2012

A new water‐soluble complex, Re(CO)3(pterin)(H2O), was synthesized and characterized by 1H NMR and FTIR spectroscopy, and by a combination of three mass spectrometry techniques: MALDI, probe electrospray ionisation (PESI), and ESI. Because, unlike most metal‐pterin complexes, the ReI complex is quite soluble in water, appropriate single crystals could be obtained for structural X‐ray analysis. We report here the first solid state molecular structure containing a pterin ligand coordinated to the Re(CO)3 core. This determination revealed that strong H bonds between the hydrogen atom of the 2‐amino group and crystallization water molecules give rise to a polymeric arrangement of Re(CO)3(pterin)(H2O) complexes in the lattice. Protonation studies in aqueous solutions of the ReI complex showed two acid‐base equilibriums with pKa1 = 3.9 and pKa2 = 8.8. pKa1 was assigned to the protonation equilibrium at N3 of the pterin ligand in the complex and pKa2 could be ascribed to the deprotonation of a coordinated water molecule.
The Use of a Nitroxide Probe in DMSO to Capture Free Radicals in Particulate Pollution
Authors: Stevanovic Svetlana , Miljevic Branka , Eaglesham Geoff K. , Bottle Steven E. , Ristovski Zoran D. , Fairfull‐Smith Kathryn E.
Published: September 2012

A profluorescent nitroxide was used to evaluate the oxidative potential of pollution derived from a compression ignition engine fuelled with biodiesel. The reaction products responsible for the observed fluorescence increase when a DMSO solution of nitroxide was exposed to biodiesel exhaust were determined by using HPLC/MS. The main fluorescent species was identified as a methanesulfonamide adduct arising from the reaction of the nitroxide with DMSO‐derived sulfoxyl radicals.
Preparation of NH‐Pyrroles under Superelectrophilic Conditions by an Aza‐Nazarov Reaction Cascade with Indole as Neutral Leaving Group: Experiment and Theory
Authors: Narayan Rishikesh , Daniliuc Constantin‐Gabriel , Würthwein Ernst‐Ulrich
Published: September 2012

Aza‐Nazarov reactions starting from 1‐azapenta‐1,4‐dien‐3‐ones offer an attractive route to five‐membered nitrogen heterocycles such as N‐substituted pyrroles. It has now been discovered that N‐indolinylhydrazone‐derived 1‐azapenta‐1,4‐dien‐3‐one 9a gives different products under conditions of varying acidity. Under strongly acidic conditions (2 equiv. of triflic acid, dilute solution, “electrophilic” conditions) it simply undergoes an aza‐Nazarov reaction to give N‐indolinylpyrrole 15a after workup with acetic anhydride. If, however, a large excess of triflic acid is used (7–10 equiv., concentrated solution, “superelectrophilic” conditions), 9a has been found to undergo an aza‐Nazarov reaction cascade followed by N–N bond cleavage to give NH‐pyrrole 10a and acetylated indole 8 as the final products (after workup with acetic anhydride). High‐level quantum chemical calculations were used to explain this acid‐concentration‐dependent reaction cascade. The formation of the reaction products can be explained in terms of an electrocyclization reaction of the protonated starting material 9a and a subsequent N–N bond cleavage reaction involving either mono‐ or dicationic species under strongly acidic conditions.
IEF‐based multidimensional applications in proteomics: Toward higher resolution
Authors: Stoyanov Alexander
Published: September 2012

This review focuses on the alternative isoelectrofocusing methods and IEF‐related techniques in protein analysis and characterization. The main emphasis is placed on the evaluation of the resolving power of new approaches, as well as potential advantages of IEF‐related techniques for multidimensional analysis. In particular, the inverse 2D gel electrophoresis where the Mw separation stage precedes IEF mode is considered.
Water Flow in, Through, and Around the Gas Diffusion Layer
Authors: Gauthier E. , Duan Q. , Hellstern T. , Benziger J.
Published: September 2012

Liquid water produced in polymer electrolyte membrane fuel cells is transported from the cathode catalyst/membrane interface through the gas diffusion layer (GDL) to the gas flow channel. Liquid water travels both laterally (in the plane of GDL) and transversely through the largest pores of the porous GDL structure. Narrow apertures in the largest pores are the primary resistance to liquid water penetration. Carbon paper has limiting apertures ∼20 μm in diameter and ∼1 μm in length whereas carbon cloth has apertures ∼100 μm in diameter and ∼200 μm in length. After sufficient hydrostatic pressure is applied, water penetrates the limiting aperture and flows through the pore. The pressure required for water to flow through the pores is less than the pressure to penetrate the limiting aperture of the pores. Water moved laterally and directed through a small number of transverse pores. There is less resistance to lateral liquid water flow at the interface between the GDL and a solid surface than through the GDL. The results from these experiments suggest that water flow through the GDL is dominated by a small number of pores and most pores remain free of liquid water.
Estradiol‐induced increase in novel object recognition requires hippocampal NR2B‐containing NMDA receptors
Authors: Vedder Lindsey C. , Smith Caroline C. , Flannigan Alaina E. , McMahon Lori L.
Published: September 2012

17β‐estradiol (E2), at high circulating levels, enhances learning and memory in many women, making it a clinical treatment for hormone‐related cognitive decline in aging. However, the mechanisms stimulated by E2, which are responsible for its cognitive enhancing effects, remain incompletely defined. Using an ovariectomized rat model, we previously reported that increasing plasma E2 enhances the magnitude of long‐term potentiation (LTP) at hippocampal CA3‐CA1 synapses, which is caused by a selective increase in current mediated by NR2B‐containing NMDARs, leading to an increase in the NMDAR/AMPAR ratio. Whether the increase in NR2B current is causally related to the ability of E2 to enhance hippocampal dependent learning and memory has yet to be tested. Here, we find that E2 enhances performance in the novel object recognition (NOR) task with the same time course we previously showed E2 enhances the LTP magnitude, temporally linking the increase in LTP to enhanced learning and memory. Furthermore, using the selective NR2B subunit antagonist Ro25‐6981, we find that the E2‐enhanced NOR, like the enhanced LTP, requires hippocampal NR2B‐containing NMDARs, specifically in area CA1. Finally, using whole‐cell recordings and the phosphatase inhibitor orthovanadate, we investigated whether the E2‐induced increase in NMDAR current is caused by an increase in the density of synaptic NMDARs and/or an increase in NMDAR subunit phosphorylation. We find that both mechanisms are responsible for the enhanced NMDAR current in E2‐treated rats. Our results show that the E2‐enhanced NOR requires a functional increase in NR2B‐containing NMDARs, a requirement shared with the E2‐enhanced LTP magnitude at CA3‐CA1 synapses, supporting the hypothesis that the increase in LTP likely contributes to the enhanced learning and memory following an increase in plasma E2 levels. © 2012 Wiley Periodicals, Inc.
Optical molecular imaging detects changes in extracellular pH with the development of head and neck cancer
Authors: Loja Melissa N. , Luo Zhen , Greg Farwell D. , Luu Quang C. , Donald Paul J. , Amott Deborah , Truong Anh Q. , Gandour‐Edwards Regina F. , Nitin N.
Published: September 2012

Noninvasive localized measurement of extracellular pH in cancer tissues can have a significant impact on the management of cancer. Despite its significance, there are limited approaches for rapid and noninvasive measurement of local pH in a clinical environment. In this study, we demonstrate the potential of noninvasive topical delivery of Alexa‐647 labeled pHLIP (pH responsive peptide conjugated with Alexa Fluor® 647) to image changes in extracellular pH associated with head and neck squamous cell carcinoma using widefield and high resolution imaging. We report a series of preclinical analyses to evaluate the optical contrast achieved after topical delivery of Alexa‐647 labeled pHLIP in intact fresh human tissue specimens using widefield and high‐resolution fluorescence imaging. Using topical delivery, Alexa‐647 labeled pHLIP can be rapidly delivered throughout the epithelium of intact tissues with a depth exceeding 700 µm. Following labeling with Alexa‐647 labeled pHLIP, the mean fluorescent contrast increased four to eight fold higher in clinically abnormal tissues as compared to paired clinically normal biopsies. Furthermore, the imaging approach showed significant differences in fluorescence contrast between the cancer and the normal biopsies across diverse patients and different anatomical sites (unpaired comparison). The fluorescence contrast differences between clinically abnormal and normal tissues were in agreement with the pathologic evaluation. Topical application of fluorescently labeled pHLIP can detect and differentiate normal from cancerous tissues using both widefield and high resolution imaging. This technology will provide an effective tool to assess tumor margins during surgery and improve detection and prognosis of head and neck cancer.
Measuring the kinetics and activity of adsorbed proteins: In vitro lysozyme deposited onto hydrogel contact lenses over short time periods
Authors: Hall B. , Jones L. , Forrest J. A.
Published: September 2012

A new process has been developed to determine the biological activity of an intact layer of lysozyme deposited onto a biomaterial surface. This process is applied to a number of common hydrogel contact lenses. The activity of the surface‐adsorbed protein is measured using a standard micrococcal activity assay, with extra steps to distinguish between protein on the surface and protein in solution. This is in contrast to protein extraction work in which the activity of all adsorbed protein is measured. For ionic materials, which are known to deposit large amounts of protein, particularly positively charged proteins such as lysozyme, there is evidence for loosely bound protein re‐entering the solution, thus making it impossible to truly separate out the surface‐adsorbed protein. This optimized process provides the first quantification of the biological activity of an intact layer of surface‐adsorbed protein at a hydrogel interface. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 755–764, 2013.
Three‐dimensional pore structure analysis of Nano/Microfibrous scaffolds using confocal laser scanning microscopy
Authors: Bagherzadeh Roohollah , Latifi Masoud , Najar Saeed Shaikhzadeh , Tehran Mohammad Amani , Kong Lingxue
Published: September 2012

Specific internal pore architectures are required to provide the needed biological and biophysical functions for fibrous scaffolds as these architectures are critical to cell infiltration and in‐grows performance. However, the key challenging on evaluating 3D pore structure of fibrous scaffolds for better understanding the capability of different structures for biological application is not well investigated. This article reports a fast, accurate, nondestructive, and comprehensive evaluation approach based on confocal laser scanning microscopy (CLSM) and three‐dimensional image analysis to study the pore structure and porosity parameters of Nano/Microfibrous scaffolds. Also a new method of making the fiber fluorescent using quantum dots (QDs) was applied before 3D imaging. Fibrous scaffolds with different porosity parameters produced by electrospinning and their 3D‐pore structure was evaluated by this approach and the results were compared to results of capillary flow porometry. The pore structural properties measured in this approach are in good agreement with that measured by the capillary flow porometry (with significant level 0.05). Furthermore, the introduced approach can measure the pore interconnectivity of the scaffold. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 765–774, 2013.
A low elastic modulus Ti‐Nb‐Hf alloy bioactivated with an elastin‐like protein‐based polymer enhances osteoblast cell adhesion and spreading
Authors: González Marta , Salvagni Emiliano , Rodríguez‐Cabello José C. , Rupérez Elisa , Gil Francisco J. , Peña Javier , Manero José M.
Published: September 2012

β‐type titanium alloys with low Young's modulus are desirable to reduce stress shielding effect and enhance bone remodeling for implants used to substitute failed hard tissue. For biomaterials application, the surface bioactivity is necessary to achieve optimal osseointegration. In the previous work, the low elastic modulus (43 GPa) Ti‐25Nb‐16Hf (wt %) alloy was mechanically and microstructurally characterized. In the present work, the biological behavior of Ti‐25Nb‐16Hf was studied. The biological response was improved by surface modification. The metal surface was modified by oxygen plasma and subsequently silanized with 3‐chloropropyl(triethoxy)silane for covalent immobilization of the elastin‐like polymer. The elastin‐like polymer employed exhibits RGD bioactive motives inspired to the extracellular matrix in order to improve cell adhesion and spreading. Upon modification, the achieved surface presented different physical and chemical properties, such as surface energy and chemical composition. Subsequently, osteoblast adhesion, cell numbers, and differentiation studies were performed to correlate surface properties and cell response. The general tendency was that the higher surface energy the higher cell adhesion. Furthermore, cell culture and immunofluorescence microscopy images demonstrated that RGD‐modified surfaces improved adhesion and spreading of the osteoblast cell type. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 819–826, 2013.
Calcium phosphate cements loaded with basic fibroblast growth factor: Delivery and in vitro cell response
Authors: Perez Roman A. , Kim Tae‐Hyun , Kim Meeju , Jang Jun‐Hyeog , Ginebra Maria‐Pau , Kim Hae‐Won
Published: September 2012

Combining calcium phosphate cements (CPCs) with bioactive molecules improves their bone regeneration potential. Although CPCs are highly osteoconductive, sometimes they have limited biological responses, especially in terms of cell proliferation. Here, we used basic fibroblast growth factor (bFGF) in an α‐tricalcium phosphate cement with different initial powder sizes (coarse vs. fine; designated as CPC‐C and CPC‐F, respectively) and investigated the behavior of bFGF loading and release, as well as the effects on osteoblast responses. bFGF was loaded at 10 μg/ml or 25 μg/ml onto the set form of two types of CPCs, aiming to allow penetration into the pore structure and adsorption onto the cement crystallites. The CPC formulated with fine powder (CPC‐F) had higher specific surface area and smaller‐sized pores and retained slightly higher amounts of bFGF within the structure. The bFGF release study performed for 3 weeks showed a sustained‐release profile; after an initial rapid release over approximately 3 days, further release pattern was almost linear. Compared to CPC‐F, CPC‐C showed a much faster release pattern. The effects of the bFGF incorporation within CPCs on cellular responses were assessed in terms of cell proliferation using MC3T3‐E1 pre‐osteoblastic cells. Compared with bFGF‐free CPCs (both CPC‐C and CPC‐F), those containing bFGF stimulated cell proliferation for up to 7 days. An inhibition study of bFGF receptor demonstrated that the improvement of cell proliferation resulted from the role of bFGF released from the CPCs. This study provides beneficial information on improving the biological properties of CPCs by combining them with specific therapeutic molecules, and particularly with bFGF, showing that the cell proliferative ability was significantly stimulated, which may have potential applications for further use in stem cell‐based bone tissue engineering. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Light induced hydrophilicity and osteoblast adhesion promotion on amorphous TiO2
Authors: Terriza Antonia , Díaz‐Cuenca Aránzazu , Yubero Francisco , Barranco Angel , González‐Elipe Agustín R. , Gonzalez Caballero Juan Luis , Vilches José , Salido Mercedes
Published: September 2012

We have studied the effect of the UV induced superhydrophilic wetting of TiO2 thin films on the osteoblasts cell adhesion and cytoskeletal organization on its surface. To assess any effect of the photo‐catalytic removal of adventitious carbon as a factor for the enhancement of the osteoblast development, 100 nm amorphous TiO2 thin layers were deposited on polyethylene terephthalate (PET), a substrate well known for its poor adhesion and limited wettability and biocompatibility. The TiO2/PET materials were characterized by X‐ray photoelectron spectroscopy, and atomic force microscopy and their wetting behavior under light illumination studied by the sessile drop method. The amorphous TiO2 thin films showed a very poor photo‐catalytic activity even if becoming superhydrophilic after illumination. The illuminated samples recovered partially its initial hydrophobic state only after their storage in the dark for more than 20 days. Osteoblasts (HOB) were seeded both on bare PET and on TiO2/PET samples immediately after illumination and also after four weeks storage in darkness. Cell attachment was much more efficient on the immediately illuminated TiO2/PET samples, with development of focal adhesions and cell traction forces. Although we cannot completely discard some photo‐catalytic carbon removal as a factor contributing to this cell enhanced attachment, our photodegradation experiments on amorphous TiO2 are conclusive to dismiss this effect as the major cause for this behavior. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Scale morphology and flexibility in the shortfin mako Isurus oxyrinchus and the blacktip shark Carcharhinus limbatus
Authors: Motta Philip , Habegger Maria Laura , Lang Amy , Hueter Robert , Davis Jessica
Published: September 2012

Cover illustration. The shortfin mako Isurus oxyrinchus is perhaps the fastest swimming shark. The modified
scales on the lateral flank of the shark are highly flexible and are believed to erect during rapid swimming. Erection of the flank scales and resulting drag reduction is hypothesized to be passively driven by localized flow patterns over the skin. The cover image, “Mako Moon”, is courtesy of Don Ray of donrayart.com. See Motta et al., pp. 1096–1110 in this issue of the Journal of Morphology.
Environmental standards and labor productivity: Understanding the mechanisms that sustain sustainability
Authors: Delmas Magali A. , Pekovic Sanja
Published: September 2012

In the last decade, a rising number of firms have adopted voluntary international environmental management and product standards, such as the international ISO 14001 management standard or organic certification. Although emerging research analyzes the impact of these standards on environmental and financial performance, there is to our knowledge no empirical research on how they affect the productivity of employees. In this paper, we investigate the direct relationship between environmental standards and labor productivity, as well as two mediating mechanisms through which environmental standards influence labor productivity: employee training and enhanced interpersonal contacts within the firm. Our empirical results, based on a French employer–employee survey from 5220 firms, reveal that firms that have adopted environmental standards enjoy a one standard deviation higher labor productivity than firms that have not adopted such standards. Copyright © 2012 John Wiley & Sons, Ltd.
Cyclic Side‐Chain Phenylazo Naphthalene Polymers: Enhanced Fluorescence Emission and Surface Relief Grating Formation
Authors: Zhang Hao , Zhou Nianchen , Zhu Xing , Chen Xinrong , Zhang Zhengbiao , Zhang Wei , Zhu Jian , Hu Zhijun , Zhu Xiulin
Published: September 2012

Well‐defined cyclic‐polymers (cyclic‐PAzoMMAs), bearing side‐chain phenylazo naphthalene chromophore, were successfully synthesized by the combination of atom transfer radical polymerization (ATRP) and copper(I)‐catalyzed azide/alkyne cycloaddition “click” reaction, as verified by GPC, 1H NMR, FTIR, and MALDI‐TOF mass spectrometry. The cyclic‐PAzoMMA showed higher glass transition temperatures than the linear‐PAzoMMA with the same molecular weight. Interestingly, the cyclic‐PAzoMMA exhibited deeper modulation depth (M.D.) induced by SRG, larger value of the photoinduced birefringence, increased fluorescence emission, and longer fluorescence lifetime in comparison with its linear counterpart.
Grape seed proanthocyanidins repress the hepatic lipid regulators miR‐33 and miR‐122 in rats
Authors: Baselga‐Escudero Laura , Bladé Cinta , Ribas‐Latre Aleix , Casanova Ester , Salvadó M. Josepa , Arola Lluis , Arola‐Arnal Anna
Published: September 2012

Scope

One major health problem in westernized countries is dysregulated fatty acid and cholesterol metabolism that causes pathologies such as metabolic syndrome. Previous studies from our group have shown that proanthocyanidins, which are the most abundant polyphenols in the human diet, regulate lipid metabolism and are potent hypolipidemic agents. The noncoding RNAs, miR‐33 and miR‐122, regulate genes that are involved in lipid metabolism.

Methods and results

Here, we show that grape seed proanthocyanidins rapidly and transiently repressed the expression of miR‐33 and miR‐122 in rat hepatocytes in vivo and in vitro. Furthermore, the miR‐33 target gene ATP‐binding cassette A1 and the miR‐122 target gene fatty acid synthase were also modulated by proanthocyanidins. Specifically, ATP‐binding cassette A1 mRNA and protein levels were increased, and fatty acid synthase mRNA and protein levels were reduced after the miRNA levels were altered.

Conclusion

These results suggest that proanthocyanidin treatment increased hepatic cholesterol efflux to produce new HDL particles by repressing miR‐33, and it reduced lipogenesis by repressing miR‐122. These results highlight a new mechanism by which grape seed proanthocyanidins produce hypolipidemia through their effects on miRNA modulators of lipid metabolism.
Neuromuscular ultrasound for evaluation of the diaphragm
Authors: Sarwal Aarti , Walker Francis O. , Cartwright Michael S.
Published: September 2012

Neuromuscular clinicians are often asked to evaluate the diaphragm for diagnostic and prognostic purposes. Traditionally, this evaluation is accomplished through history, physical exam, fluoroscopic sniff test, nerve conduction studies, and electromyography (EMG). Nerve conduction studies and EMG in this setting are challenging, uncomfortable, and can cause serious complications, such as pneumothorax. Neuromuscular ultrasound has emerged as a non‐invasive technique that can be used in the structural and functional assessment of the diaphragm. In this study we review different techniques for assessing the diaphragm using neuromuscular ultrasound and the application of these techniques to enhance diagnosis and prognosis by neuromuscular clinicians. Muscle Nerve 47:319‐329, 2013
Preparation, thermal properties, and morphology of graft copolymers in reactive blends of PHBV and PPC
Authors: Li J. , Sun C.R. , Zhang X.Q.
Published: September 2012

Chemical modification of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) with glycidyl methacrylate (GMA) monomer, followed by reactively blending with end‐capped poly(propylene carbonate) (PPC) (50 wt%) was carried out during melt processing with dicumyl peroxide (DCP) initiation. The two kinds of graft copolymers of PHBV‐g‐GMA and PHBV‐g‐PPC were extracted with Soxhlet's apparatus, respectively. These grafting reaction mechanisms were proposed and the presence of grafting copolymers was confirmed by weight analysis, FTIR and NMR. The methyne carbon of GMA is confirmed to attach to quaternary carbon of the PHBV backbone. The epoxy groups in the copolymer of PHBV‐g‐GMA were capable to react with the carboxyl groups of end‐capped PPC, resulting in the formation of PHBV‐g‐PPC copolymer in situ. Their thermal properties and morphology were also characterized by DSC, WAXD, POM, and AFM. It revealed that after GMA grafting, the degradation of PHBV decreased and the nucleation of PHBV improved. The crystallinity degree, spherulites dimension and phase segregation between the two macromolecules decreased after PHBV grafted with PPC. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Storage‐induced changes of the cytosolic red blood cell proteome analyzed by 2D DIGE and high‐resolution/high‐accuracy MS
Authors: Walpurgis Katja , Kohler Maxie , Thomas Andreas , Wenzel Folker , Geyer Hans , Schänzer Wilhelm , Thevis Mario
Published: September 2012

The storage of packed red blood cells (RBCs) is associated with the development of morphological and biochemical changes leading to a reduced posttransfusion functionality and viability of the cells. Within this study, 2D DIGE and high‐resolution/high‐accuracy Orbitrap MS were used to analyze the storage‐induced changes of the cytosolic RBC proteome and identify characteristic protein patterns and potential marker proteins for the assessment of RBC storage lesions. Leukodepleted RBC concentrates were stored according to standard blood bank conditions for 0, 7, 14, 28, and 42 days and analyzed by using a characterized and validated protocol. Following statistical evaluation, a total of 14 protein spots were found to be significantly altered after 42 days of ex vivo storage. Protein identification was accomplished by tryptic digestion and LC‐MS/MS and three proteins potentially useful as biomarkers for RBC aging comprising transglutaminase 2, beta actin, and copper chaperone for superoxide dismutase were selected and validated by western blot analysis. These can serve as a basis for the development of a screening assay to detect RBC storage lesions and autologous blood doping in sports.
Synthesis of novel dithienothiophene‐ and 2,7‐carbazole‐based conjugated polymers and H‐bonded effects on electrochromic and photovoltaic properties
Authors: Fang Hsiao‐Ping , Lin Jia‐Wei , Chiang I‐Hung , Chu Chih‐Wei , Wei Kung‐Hwa , Lin Hong‐Cheu
Published: September 2012

Three kinds of dithienothiophene/carbazole‐based conjugated polymers (P1–P3), which bear acid‐protected and benzoic acid pendants in P2 and P3, respectively, were synthesized via Suzuki coupling reaction. Interestingly, P1–P3 exhibited reversible electrochromism during the oxidation processes of cyclic voltammogram studies, and P3 (with H‐bonds) revealed the best electrochromic property with the most noticeable color change. According to powder X‐ray diffraction (XRD) analysis, these polymers exhibited obvious diffraction features indicating bilayered packings between polymer backbones and π‐π stacking between layers in the solid state. Compared with the XRD data of P2 (without H‐bands), H‐bonds of P3 induced a higher crystallinity in the small‐angle region (corresponding to a higher ordered bilayered packings between polymer backbones), but with a similar crystallinity in the wide angle region indicating a comparable π‐π stacking distance between layers. Moreover, based on the preliminary photovoltaic properties of PSC devices (P1–P3 blended individually with PCBM acceptor in the weight ratio of 1:1), P3 (with H‐bonds) possessed the highest power conversion efficiency of 0.61% (with Jsc = 2.26 mA/cm2, FF = 29.8%, and Voc = 0.9 V). In contrast to P2 (without H‐bands), the thermal stability, crystallinity, and electrochromic along with photovoltaic properties of P3 were generally enhanced due to its H‐bonded effects. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis, characterization, photo‐induced alignment, and surface orientation of poly(9,9‐dioctylfluorene‐alt‐azobenzene)s
Authors: Kinashi Kenji , Kambe Yuki , Misaki Masahiro , Koshiba Yasuko , Ishida Kenji , Ueda Yasukiyo
Published: September 2012

Three types of bi‐functionalized copolymers (P1FAz, P2FAz, and P3FAz) with different numbers of fluorene units and an azobenzene unit were synthesized and characterized using UV–vis and polarized absorption spectroanalysis. The trans‐cis photoisomerization was conformed under 400 nm light irradiation for all copolymers in chloroform. However, in the film state, only the trans‐cis photoisomerization occurred by mono‐fluorene attached copolymer poly[(9,9‐di‐n‐octylfluorenyl‐2,7‐diyl)‐alt‐4,4′‐azobenzene)] (P1FAz). Photo‐induced alignment was achieved using the P1FAz film after irradiation with linear polarized 400 nm light and subsequent annealing at 60 °C. Surface orientation of a spin‐coating film of poly(9,9‐didodecylfluorene) (F12) was achieved using the photo‐induced alignment layer of the P1FAz film after annealing at 90 °C. The photo‐induced alignment layer of P1FAz has potential application to the surface orientation technique for appropriate polymers, which will be useful for the fabrication of optoelectronics devices. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Living cationic polymerization of vinyl ethers with a naphthyl group: Decisive effect of the substituted position on naphthalene ring
Authors: Shinke Yu , Kanazawa Arihiro , Kanaoka Shokyoku , Aoshima Sadahito
Published: September 2012

Living cationic polymerization of a vinyl ether with a naphthyl group [2‐(2‐naphthoxy)ethyl vinyl ether, βNpOVE] was achieved using base‐assisting initiating systems with a Lewis acid. The Et1.5AlCl1.5/1,4‐dioxane or ethyl acetate system induced the living cationic polymerization of βNpOVE in toluene at 0 °C. The living nature of this reaction was confirmed by a monomer addition experiment, followed by 1H NMR and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) analyses. In contrast, the polymerization of αNpOVE was not fully controlled; under similar conditions, it produced polymers with broad molecular weight distributions. The 1H NMR and MALDI‐TOF‐MS spectra of the resultant poly(αNpOVE) revealed that the products had undesirable structures derived from Friedel–Crafts alkylation. The higher reactivity of αNpOVE in electrophilic substitution reactions, such as the Friedel–Crafts reaction, was attributable to the greater electron density of the naphthyl ring, which was calculated based on frontier orbital theory. The naphthyl groups significantly affected the properties of the resultant polymer. For example, the glass transition temperatures (Tg) of poly(NpOVE)s are higher by approximately 40 °C than that of poly(2‐phenoxyethyl vinyl ether). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
SET‐LRP of acrylonitrile catalyzed by tin powder
Authors: Hao Zhihai , Chen Hou , Liu Delong , Fan Lijun
Published: September 2012

Sn(0)‐mediated single electron transfer‐living radical polymerization (SET‐LRP) of acrylonitrile (AN) with carbon tetrachloride (CCl4) as initiator and hexamethylenetetramine (HMTA) as ligand in N, N‐dimethylformamide (DMF) was studied. The polymerization obeyed first order kinetic. The molecular weight of polyacrylonitrile (PAN) increased linearly with monomer conversion and PAN exhibited narrow molecular weight distributions. Increasing the content of Sn(0) resulted in an increase in the molecular weight and the molecular weight distribution. Effects of ligand and initiator were also investigated. The block copolymer PAN‐b‐polymethyl methacrylate with molecular weight at 126,130 and polydispersity at 1.36 was successfully obtained. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Network structure and thermomechanical properties of hybrid DGEBA networks cured with 1‐methylimidazole and hyperbranched poly(ethyleneimine)s
Authors: Fernández‐Francos Xavier , Santiago David , Ferrando Francesc , Ramis Xavier , Salla Josep M. , Serra Àngels , Sangermano Marco
Published: September 2012

The use of commercially available hyperbranched poly(ethyleneimine)s (Lupasol™, BASF) as polymeric modifiers in diglycidyl ether of bisphenol A thermosetting formulations using 1‐methylimidazole (MI) as anionic initiator has been studied. Poly(ethyleneimine)s can get incorporated into the network structure by condensation of amine and epoxy groups. The excess, over‐stoichiometric epoxy groups can undergo anionic homopolymerization initiated by MI. The thermal, dynamomechanical, and mechanical properties of the resulting materials have been determined using DSC, thermomechanical analysis (TMA), dynamomechanical analysis (DMA), and mechanical testing. The effect of the different amine modifiers on the MI networks, determined by their structure, is complex. Low initiator content and high molecular weight modifiers create significant mobility restrictions, which have a strong effect on the glass transition temperature and the apparent crosslinking density of the cured materials. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Extruder‐made TPO nanocomposites. I. Effect of maleated polypropylene and organoclay ratio on the morphology and mechanical properties
Authors: Tiwari Rajkiran R. , Hunter Douglas L. , Paul Donald R.
Published: September 2012

PP/PP‐g‐MA/MMT/EOR blend nanocomposites were prepared in a twin‐screw extruder at fixed 30 wt % elastomer and 0 to 7 wt % MMT content. Elastomer particle size and shape in the presence of MMT were evaluated at various PP‐g‐MA/organoclay masterbatch ratios of 0, 0.5, 1.0, and 1.5. The organoclay dispersion facilitated by maleated polypropylene serves to reduce the size of the elastomer dispersed phase particles and facilitates toughening of these blend nanocomposites. The rheological data analysis using modified Carreau‐Yasuda model showed maximum yield stress in extruder‐made nanocomposites compared with nanocomposites of reactor‐made TPO. Increasing either MMT content or the PP‐g‐MA/organoclay ratio can drive the elastomer particle size below the critical particle size below which toughness is dramatically increased. The ductile‐brittle transition shift toward lower MMT content as the PP‐g‐MA/organoclay ratio is increased. The D‐B transition temperature also decreased with increased MMT content and masterbatch ratio. Elastomer particle sizes below ∼1.0 μm did not lead to further decrease in the D‐B transition temperature. The tensile modulus, yield strength, and elongation at yield improved with increasing MMT content and masterbatch ratio while elongation at break was reduced. The modified Mori‐Tanaka model showed better fit to experimental modulus when the effect of MMT and elastomer are considered individually. Overall, extruder‐made nanocomposites showed balanced properties of PP/PP‐g‐MA/MMT/EOR blend nanocomposites compared with nanocomposites of reactor‐made TPO. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Electrical and optical simulations of a polymer‐based phosphorescent organic light‐emitting diode with high efficiency
Authors: Al‐Sa'di Mahmoud , Jaiser Frank , Bagnich Sergey , Unger Thomas , Blakesley James , Wilke Andreas , Neher Dieter
Published: September 2012

A comprehensive numerical device simulation of the electrical and optical characteristics accompanied with experimental measurements of a new highly efficient system for polymer‐based light‐emitting diodes doped with phosphorescent dyes is presented. The system under investigation comprises an electron transporter attached to a polymer backbone blended with an electronically inert small molecule and an iridium‐based green phosphorescent dye which serves as both emitter and hole transporter. The device simulation combines an electrical and an optical model. Based on the known highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of all components as well as the measured electrical and optical characteristics of the devices, we model the emissive layer as an effective medium using the dye's HOMO as hole transport level and the polymer LUMO as electron transport level. By fine‐tuning the injection barriers at the electron and hole‐injecting contact, respectively, in simulated devices, unipolar device characteristics were fitted to the experimental data. Simulations using the so‐obtained set of parameters yielded very good agreement to the measured current–voltage, luminance–voltage characteristics, and the emission profile of entire bipolar light‐emitting diodes, without additional fitting parameters. The simulation was used to gain insight into the physical processes and the mechanisms governing the efficiency of the organic light‐emitting diode, including the position and extent of the recombination zone, carrier concentration profiles, and field distribution inside the device. The simulations show that the device is severely limited by hole injection, and that a reduction of the hole‐injection barrier would improve the device efficiency by almost 50%. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Structural and chemical characterization of nanocrystalline and amorphous hydrogenated Si films
Authors: Garozzo Cristina , Puglisi Rosaria Anna , Lombardo Salvatore
Published: September 2012

We present a study on the morphological evolution of hydrogenated amorphous silicon layers obtained by plasma enhanced chemical vapor deposition at different H dilutions in the regime close to the formation of the nanocrystalline (nc‐Si) phase. The role of hydrogen in the transition from the amorphous to the crystalline phase is investigated by accurate structural and chemical characterisation, from the early stages of nucleation, where the nuclei present a size slightly larger than the critical nucleus, i.e. about 0.8 nm in radius, up to the formation of crystalline grains larger than 30 nm in radius. Hydrogen is found to have a crucial role in the transition from a‐Si:H to nc‐Si:H, since it forms an intermediate bond‐centred Si–H–Si configuration, and when the H moves away from the bond‐centred location, the strained Si–Si bonds either break or relax, undergoing local structural rearrangements closer to those of c‐Si. During this phase transition a part of H bonds at grain boundaries. A correlation between the structural characteristics of the crystalline phase and the bonding mechanism of Si with H through multiple hydrides, such as Si‐H2 and Si‐H3 is found. Particularly the SiH3 are found to be directly correlated to the shape and the size of the nanocrystallites present in the films (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Robust and Aligned Carbon Nanotube/Titania Core/Shell Films for Flexible TCO‐Free Photoelectrodes
Authors: Di Jiangtao , Yong Zhenzhong , Yao Zhaojun , Liu Xiangyang , Shen Xiaojuan , Sun Baoquan , Zhao Zhigang , He Huixin , Li Qingwen
Published: September 2012

Carbon nanotube (CNT)/semiconducting oxide hybrids are an ideal architecture for light‐harvesting devices, in which the CNTs are expected to not only act as a scaffold but also provide fast transport paths for photogenerated charges in the oxide. However, the current potential of CNTs for charge transport is largely suppressed due to the nanotubes not being interconnected but isolated by the low conductive oxide coatings. Herein, a flexible and conductive CNT/TiO2 core/shell heterostructure film is reported, with aligned and interconnected CNTs wrapped in a continuous TiO2 coating. Without using additional transparent conducting oxide (TCO) substrates, this unique feature of the film boosts the incident photon‐to‐electron conversion efficiency to 32%, outperforming TiO2 nanoparticle electrodes fabricated on TCO substrates. Moreover, the film shows high structural stability and can generate a stable photocurrent even after being bent hundreds of times.