bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel injectable biodegradable glycol chitosan‐based hydrogels crosslinked by Michael‐type addition reaction with oligo(acryloyl carbonate)‐b‐poly(ethylene glycol)‐b‐oligo(acryloyl carbonate) copolymers
Authors: Yu Yuexin , Deng Chao , Meng Fenghua , Shi Qin , Feijen Jan , Zhong Zhiyuan 
Published: September 2011

AbstractNovel injectable biodegradable glycol chitosan hydrogels were developed based on thiolated glycol chitosan (GC‐SH) and water soluble oligo(acryloyl carbonate)‐b‐ poly(ethylene glycol)‐b‐oligo(acryloyl carbonate) (OAC‐PEG‐OAC) triblock copolymers via Michael‐type addition reaction. The rheology measurements showed that robust hydrogels were formed rapidly upon mixing aqueous solutions of GC‐SH and OAC‐PEG‐OAC at remarkably low total polymer concentrations of 1.5–4.5 wt % under physiological conditions. The gelation times (varying from 10 s to 17 min) and storage moduli (100 to 4300 Pa) of hydrogels could be controlled by degrees of substitution (DS) of GC‐SH, solution pH, and polymer concentration. These glycol chitosan hydrogels had microporous structures, low swelling and slow hydrolytic degradation (stable for over 6 months) under physiological conditions. Notably, these hydrogels were prone to enzymatic degradation with lysozyme. The multiple acryloyl functional groups of OAC‐PEG‐OAC allowed facile conjugation with thiol‐containing biomolecules prior to gelation endowing hydrogels with specific bioactivity. The preliminary cell culture studies revealed that these glycol chitosan hydrogels were cell non‐adhesive while Gly‐Arg‐Gly‐Asp‐Cys (GRGDC) peptide modified hydrogels could well support adhesion and growth of both MG63 osteoblast and L929 fibroblast cells. These rapidly in situ forming enzymatically biodegradable hybrid hydrogels have great potentials in the development of injectable cell‐specific bioactive extracellular matrices for tissue engineering. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Dual‐functional electrospun poly(2‐hydroxyethyl methacrylate)
Authors: Zhang Bo , Lalani Reza , Cheng Fang , Liu Qingsheng , Liu Lingyun 
Published: September 2011

AbstractPoly(2‐hydroxyethyl methacrylate) (pHEMA) has been widely used in many biomedical applications due to its well‐known biocompatibility. For tissue engineering applications, porous scaffolds that mimic fibrous structures of natural extracellular matrix and possess high surface‐area‐to‐volume ratios are highly desirable. So far, a systematic approach to control diameter and morphology of pHEMA fibers has not been reported and potential applications of pHEMA fibers have barely been explored. In this work, pHEMA was synthesized and processed into fibrous scaffolds using an electrospinning approach. Fiber diameters from 270 nm to 3.6 μm were achieved by controlling polymer solution concentration and electrospinning flow rate. Post‐electrospinning thermal treatment significantly improves integrity of the electrospun membranes in water. The pHEMA microfibrous membranes exhibited water absorption up to 280% (w/w), whereas the pHEMA hydrogel only absorbed 70% water. Fibrinogen adsorption experiments demonstrate that the electrospun pHEMA fibers highly resist nonspecific protein adsorption. Hydroxyl groups on electrospun pHEMA fibers were further activated for protein immobilization. A bovine serum albumin (BSA) binding capacity as high as 120 mg BSA/g membrane was realized at an intermediate fiber diameter. The pHEMA fibrous scaffolds functionalized with collagen I significantly promoted fibroblast adhesion, spreading, and proliferation. We conclude that the electrospun pHEMA fibers are dual functional, that is, they resist nonspecific protein adsorption meanwhile abundant hydroxyl groups on fibers allow effective conjugation of biomolecules in a nonfouling background. High water absorption and dual functionality of the electrospun pHEMA fibers may lead to a number of potential applications such as wound dressings, tissue scaffolds, and affinity membranes. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Electrospun nanofiber‐based regeneration of cartilage enhanced by mesenchymal stem cells
Authors: Shafiee Abbas , Soleimani Masoud , Chamheidari Gholamreza Abedi , Seyedjafari Ehsan , Dodel Masumeh , Atashi Amir , Gheisari Yousof 
Published: September 2011

AbstractApplication of biomaterials in combination with stem cells is a novel tissue engineering approach to regenerate cartilage. The objective of this study was to investigate the potential of poly(vinyl alcohol)/polycaprolactone (PVA/PCL) nanofiber scaffolds seeded with rabbit bone marrow‐mesenchymal stem cell (BM‐MSC) for cartilage tissue engineering in vitro and in vivo. We tested the biocompatibility and mechanical properties of nanofibrous scaffolds using scanning electron microscope, MTT assay, and tensile measurements. The capacity of MSC for chondrogenic differentiation on scaffolds was examined using reverse transcription‐polymer chain reaction and immunostaining. For in vivo assessments, PVA/PCL nanofiber scaffolds with or without MSC were implanted into rabbit full‐thickness cartilage defects. To evaluate cartilage regeneration, semi‐quantitative grading and histological analysis were performed. Our results showed that PVA/PCL scaffolds supported the proliferation and chondrogenic differentiation of MSC in vitro. Moreover, the animals treated with cell‐seeded PVA/PCL scaffolds showed improved healing of defects compared with untreated control and those which received cell‐free scaffolds. Our findings suggest that PVA/PCL scaffolds incorporated with MSC can serve as a suitable graft for articular cartilage reconstruction. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 99A:467–467, 2011.
Biological constraints that limit compensation of a common skeletal trait variant lead to inequivalence of tibial function among healthy young adults
Authors: Jepsen Karl J , Centi Amanda , Duarte G Felipe , Galloway Kathleen , Goldman Haviva , Hampson Naomi , Lappe Joan M , Cullen Diane M , Greeves Julie , Izard Rachel , Nindl Bradley C , Kraemer William J , Negus Charles H , Evans Rachel K 
Published: September 2011

Abstract
Having a better understanding of how complex systems like bone compensate for the natural variation in bone width to establish mechanical function will benefit efforts to identify traits contributing to fracture risk. Using a collection of pQCT images of the tibial diaphysis from 696 young adult women and men, we tested the hypothesis that bone cells cannot surmount the nonlinear relationship between bone width and whole bone stiffness to establish functional equivalence across a healthy population. Intrinsic cellular constraints limited the degree of compensation, leading to functional inequivalence relative to robustness, with slender tibias being as much as two to three times less stiff relative to body size compared with robust tibias. Using Path Analysis, we identified a network of compensatory trait interactions that explained 79% of the variation in whole-bone bending stiffness. Although slender tibias had significantly less cortical area relative to body size compared with robust tibias, it was the limited range in tissue modulus that was largely responsible for the functional inequivalence. Bone cells coordinately modulated mineralization as well as the cortical porosity associated with internal bone multicellular units (BMU)-based remodeling to adjust tissue modulus to compensate for robustness. Although anecdotal evidence suggests that functional inequivalence is tolerated under normal loading conditions, our concern is that the functional deficit of slender tibias may contribute to fracture susceptibility under extreme loading conditions, such as intense exercise during military training or falls in the elderly. Thus, we show the natural variation in bone robustness was associated with predictable functional deficits that were attributable to cellular constraints limiting the amount of compensation permissible in human long bone. Whether these cellular constraints can be circumvented prophylactically to better equilibrate function among individuals remains to be determined. © 2011 American Society for Bone and Mineral Research
Physiological function of the angiotensin AT1a receptor in bone remodeling
Authors: Kaneko Keiko , Ito Masako , Fumoto Toshio , Fukuhara Ryoji , Ishida Junji , Fukamizu Akiyoshi , Ikeda Kyoji 
Published: September 2011

Abstract
In order to determine whether the renin-angiotensin system (RAS) has any physiologic function in bone metabolism, mice lacking the gene encoding the major angiotensin II receptor isoform, AT1a, were studied using micro CT scanning, histomorphometric, and biochemical techniques. Three-dimensional (3D) micro CT analysis of the tibial metaphysis revealed that both male and female AT1a knockout mice exhibited an increased trabecular bone volume along with increased trabecular number and connectivity. Histomorphometric analysis of the tibial metaphysis indicated that the parameters of bone formation as well as resorption were increased, which was also supported by elevated serum osteocalcin and carboxy-terminal collagen crosslink (CTX) concentrations in the AT1a-deficient mice. Osteoclastogenesis and osteoblastogenesis assays in ex vivo cultures, however, did not reveal any intrinsic alterations in the differentiation potential of AT1a-deficient cells. Quantitative RT-PCR using RNA isolated from the tibia and femur revealed that the receptor activator of NF-κB ligand (RANKL)/osteoprotegerin (OPG) ratio and the expression of stromal cell-derived factor (SDF)1α were increased, whereas that of SOST was decreased in AT1a-deficient bone, which may account for the increased bone resorption and formation, respectively. AT1a-deficient mice also displayed a lean phenotype with reduced serum leptin levels. They maintained high bone mass with advancing age, and were protected from bone loss induced by ovariectomy. Collectively, the data suggest that RAS has a physiologic function in bone remodeling, and that signaling through AT1a negatively regulates bone turnover and bone mass. © 2011 American Society for Bone and Mineral Research
Apoptosis‐ and endoplasmic reticulum stress‐related genes were regulated by estrogen and progesterone in the uteri of calbindin‐D9kand ‐D28kknockout mice
Authors: Jung Eui‐Man , An Beum‐Soo , Choi Kyung‐Chul , Jeung Eui‐Bae 
Published: September 2011

AbstractCalcium (Ca2+) is an important regulator of apoptotic signaling. Calbindin‐D9k(CaBP‐9k) and ‐D28k(CaBP‐28k) have a high affinity for Ca2+ions. Uterine calbindins appear to be involved in the regulation of myometrial activity by intracellular Ca2+. In addition, uterine calbindins are expressed in the mouse endometrium and are regulated by steroid hormones during implantation and development. The aim of the present study was to evaluate the regulation of apoptosis in the uteri of CaBP‐9k, CaBP‐28k, and CaBP‐9k/28k knockout (KO) mice. Our findings indicated that Bax protein was enhanced in the uteri of CaBP‐28k and CaBP‐9k/28k KO mice compared to wild‐type (WT) and CaBP‐9k KO mice, but no difference was observed in Bcl‐2 protein expression. The expressions of caspase 3, 6, and 7 proteins were higher in both CaBP‐28k and CaBP‐9k/28k KO mice than in WT and CaBP‐9k KO mice. These results suggest that the absence of CaBP‐28k increases apoptotic signaling. We also investigated the expression of endoplasmic reticulum (ER) stress genes by Western blot analysis in calbindin KO mice. C/EBP homologous protein and immunoglobulin heavy chain‐binding protein protein levels were elevated in CaBP‐28k KO mice compared to WT mice. When immature mice were treated with 17β‐estradiol (E2) or progesterone (P4) for 3 days, we found that the expressions of Bax and caspase 3 protein were increased by E2 treatment in WT and CaBP‐9k KO mice, and by P4 treatment in CaBP‐28k KO mice. These results indicate that CaBP‐28k blocks the up‐regulation of apoptosis‐related genes and ER stress genes, implying that CaBP‐28k may decrease the expression of genes involved in apoptosis and ER stress in murine uterine tissue. J. Cell. Biochem. 113: 194–203, 2012. © 2011 Wiley Periodicals, Inc.
The coupling constant polarizability and hyperpolarizabilty of 1J(NH) in N‐methylacetamide, and its application for the multipole spin–spin coupling constant polarizability/reaction field approach to solvation
Authors: Kjær Hanna , Sauer Stephan P. A. , Kongsted Jacob 
Published: September 2011

AbstractWe present a benchmark study of a combined multipole spin–spin coupling constant (SSCC) polarizability/reaction field (MJP/RF) approach to the calculation of both specific and bulk solvation effects on SSCCs of solvated molecules. The MJP/RF scheme is defined by an expansion of the SSCCs of the solvated molecule in terms of coupling constant dipole and quadrupole polarizabilities and hyperpolarizabilities derived from single molecule ab initio calculations. The solvent electric field and electric field gradient are calculated based on data derived from molecular dynamics (MD) simulations thereby accounting for solute–solvent dynamical effects. The MJP/RF method is benchmarked against polarizable QM/MM calculations for the one‐bond N–H coupling constant in N‐methylacetamide. The best agreement between the MJP/RF and QM/MM approaches is found by truncating the electric field expansion in the MJP/RF approach at the linear electric field level. In addition, we investigate the sensitivity of the results due to the choice of one‐electron basis set in the ab initio calculations of the coupling constant (hyper‐)polarizabilities and find that they are affected by the basis set in a way similar to the coupling constants themselves. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Using Huffman coding method to visualize and analyze DNA sequences
Authors: Qi Zhao‐Hui , Li Ling , Qi Xiao‐Qin 
Published: September 2011

AbstractOn the basis of the Huffman coding method, we propose a new graphical representation of DNA sequence. The representation can avoid degeneracy and loss of information in the transfer of data from a DNA sequence to its graphical representation. Then a multicomponent vector from the representation is introduced to characterize quantitatively DNA sequences. The components of the vector are derived from the graphical representation of DNA primary sequence. The examination of similarities and dissimilarities among the complete coding sequences of β‐globin gene of 11 species and six ND6 proteins shows the utility of the scheme. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Molecular dynamics simulations of triflic acid and triflate ion/water mixtures: A proton conducting electrolytic component in fuel cells
Authors: Sunda Anurag Prakash , Venkatnathan Arun 
Published: September 2011

AbstractTriflic acid is a functional group of perflourosulfonated polymer electrolyte membranes where the sulfonate group is responsible for proton conduction. However, even at extremely low hydration, triflic acid exists as a triflate ion. In this work, we have developed a force‐field for triflic acid and triflate ion by deriving force‐field parameters using ab initio calculations and incorporated these parameters with the Optimized Potentials for Liquid Simulations ‐ All Atom (OPLS‐AA) force‐field. We have employed classical molecular dynamics (MD) simulations with the developed force field to characterize structural and dynamical properties of triflic acid (270–450 K) and triflate ion/water mixtures (300 K). The radial distribution functions (RDFs) show the hydrophobic nature of CF3 group and presence of strong hydrogen bonding in triflic acid and temperature has an insignificant effect. Results from our MD simulations show that the diffusion of triflic acid increases with temperature. The RDFs from triflate ion/water mixtures shows that increasing hydration causes water molecules to orient around the SO3− group of triflate ions, solvate the hydronium ions, and other water molecules. The diffusion of triflate ions, hydronium ion, and water molecules shows an increase with hydration. At λ = 1, the diffusion of triflate ion is 30 times lower than the diffusion of triflic acid due to the formation of stable triflate ion–hydronium ion complex. With increasing hydration, water molecules break the stability of triflate ion–hydronium ion complex leading to enhanced diffusion. The RDFs and diffusion coefficients of triflate ions, hydronium ions and water molecules resemble qualitatively the previous findings using per‐fluorosulfonated membranes. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Optimal (v, 4, 2, 1) optical orthogonal codes with small parameters
Authors: Baicheva Tsonka , Topalova Svetlana 
Published: September 2011

AbstractOptimal (v, 4,2,1) optical orthogonal codes (OOCs) with v⩽75 and v≠71 are classified up to isomorphism. One (v, 4,2,1) OOC is presented for all v⩽181, for which an optimal OOC exists. Copyright © 2011 Wiley Periodicals, Inc. J Combin Designs 20:142‐160, 2012
Trivalent chromium removal from tannery effluent using kaolin‐supported bacterial biofilm of Bacillus sp isolated from chromium polluted soil
Authors: Fathima Aafreen , Rao Jonnalagadda Raghava , Unni Nair Balachandran 
Published: September 2011

AbstractBACKGROUND: Bacterial strains belonging to the genus Bacillus, isolated from Cr‐ polluted soil (tannery sludge) were employed as consortium for Cr(III) removal from tannery effluents. Kaolin clay, a natural adsorbent, was used as supporting material for bacterial biofilm formation. The use of clay‐supported bacterial biofilm has not previously been employed for the treatment of tannery effluents containing Cr(III) salt.RESULTS: Commercial tannery effluent containing 1000 ppm initial metal ion concentration was treated in stages. The initial Cr(III) concentration of 1000 ppm was brought down to 2 ppm, a permissible level for discharge, after the fourth stage. The bacterial isolates were found to be Bacillus subtilis VITSCCr01 and Bacillus cereus VITSCCr02 by 16s rRNA gene sequencing. Batch assay and confocal laser scanning microscopy results revealed the role of kaolin as a support material in biofilm formation. Best fit was obtained with the Freundlich adsorption isotherm. The mechanism of sorption was confirmed by Fourier transform infrared (FT‐IR) spectroscopy and scanning electron microscopy–energy dispersive X‐ray spectroscopy (SEM‐EDS).CONCLUSION: Cr(III) removal from tannery effluent using low cost adsorbents such as kaolin and bacteria proved to be effective for metal concentrations ⩽1000 ppm; this is normally not possible using conventional treatment methods. This work has demonstrated feasible sorption of Cr(III), especially during post‐tanning operations. Copyright © 2011 Society of Chemical Industry
Context matters: Combined influence of participation and intellectual stimulation on the promotion focus–employee creativity relationship
Authors: Zhou Qin , Hirst Giles , Shipton Helen 
Published: September 2011

SummaryIn this paper, we examined the interactive effects of two contexts—participation and intellectual stimulation, and promotion focus on creativity. On the basis of a multi‐organization sample of 213 employees, we tested and found that although promotion focus was positively related to creativity, the relationship between promotion focus and creativity was most positive when both participation and leader intellectual stimulation were high. We discuss the way contexts in combination influence employee creativity for promotion‐oriented individuals, through increasing decision latitude as well as stimulating and promoting creativity. Copyright © 2011 John Wiley & Sons, Ltd.
Antioxidants from barley husks impregnated in films of low‐density polyethylene and their effect over lipid deterioration of frozen cod (Gadus morhua)
Authors: Pereira de Abreu David A , Maroto Julio , Villalba Rodríguez Karen , Cruz José M 
Published: September 2011

AbstractBACKGROUND: The changes in quality of cod fillets packaged in films with and without antioxidants during 12 months of frozen storage at − 20 °C were investigated in the present study. The following parameters were determined in order to study lipid hydrolysis and primary and secondary lipid oxidation in the samples during frozen storage: peroxide value, conjugated dienes, conjugated triene hydroperoxides, free fatty acids, totox value, thiobarbituric acid‐reactive substances and p‐anisidine value.RESULTS: Films containing antioxidants isolated from barley husks were effective in slowing down lipid hydrolysis and primary and secondary lipid oxidation processes. Secondary lipid oxidation reached maximum values in the 12th month of storage in control samples and samples packaged with antioxidant‐containing film. Maximum lipid hydrolysis and lipid oxidation values for control cod samples were significantly higher than the maximum values found in samples packaged with antioxidant‐containing film.CONCLUSION: The results confirm the efficacy of natural antioxidants derived from barley husks in slowing down lipid hydrolysis and increasing the oxidative stability of cod flesh. They also demonstrate the potential usefulness of natural antioxidants extracted from barley husks in the development of active packaging films for food preservation. Copyright © 2011 Society of Chemical Industry
Evaluation of processed green and ripe mango peel and pulp flours (Mangifera indica var. Chokanan) in terms of chemical composition, antioxidant compounds and functional properties
Authors: Abdul Aziz Noor Aziah , Wong Lee Min , Bhat Rajeev , Cheng Lai Hoong 
Published: September 2011

AbstractBACKGROUND: Mango is a highly perishable seasonal fruit and large quantities are wasted during the peak season as a result of poor postharvest handling procedures. Processing surplus mango fruits into flour to be used as a functional ingredient appears to be a good preservation method to ensure its extended consumption.RESULTS: In the present study, the chemical composition, bioactive/antioxidant compounds and functional properties of green and ripe mango (Mangifera indica var. Chokanan) peel and pulp flours were evaluated. Compared to commercial wheat flour, mango flours were significantly low in moisture and protein, but were high in crude fiber, fat and ash content. Mango flour showed a balance between soluble and insoluble dietary fiber proportions, with total dietary fiber content ranging from 3.2 to 5.94 g kg−1. Mango flours exhibited high values for bioactive/antioxidant compounds compared to wheat flour. The water absorption capacity and oil absorption capacity of mango flours ranged from 0.36 to 0.87 g kg−1 and from 0.18 to 0.22 g kg−1, respectively.CONCLUSION: Results of this study showed mango peel flour to be a rich source of dietary fiber with good antioxidant and functional properties, which could be a useful ingredient for new functional food formulations. Copyright © 2011 Society of Chemical Industry