bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractNoninvasive 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

AbstractA 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

AbstractSpecific 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

Abstractβ‐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

AbstractCombining 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

AbstractWe 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

AbstractCover 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

SummaryIn 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

AbstractWell‐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

ScopeOne 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 resultsHere, 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.ConclusionThese 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.
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

AbstractChemical 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
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

AbstractThree 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

AbstractThree 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

AbstractLiving 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

AbstractSn(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

AbstractThe 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