bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and properties of methacrylate‐endcapped caprolactone networks with modulated water uptake for biomedical applications
Authors: Ivirico J. L. Escobar , Martínez E. Costa , Sánchez M. Salmerón , Criado I. Muñoz , Ribelles J. L. Gómez , Pradas M. Monleón 
Published: April 2007

AbstractMethacrylate‐endcapped caprolactone (CLMA) networks were synthesized and copolymerized with 2‐hydroxyethyl acrylate (HEA) seeking to tailor the hydrophilicity of the system. The resulting structure of the copolymer network is investigated by differential scanning calorimetry, thermogravimetry, and Fourier transform infrared spectroscopy. The dynamic swelling behavior and the equilibrium water sorption is measured and correlated with the microstructure. The experimental results allow one to conclude that the new material is a random copolymer of both components, HEA and CLMA. The effect of cell attachment and proliferation on the new copolymer networks was observed by in vitro culture of human chondrocytes up to 8 days. Enhanced cellular adhesion, similar to that obtained with tissue culture polystyrene (TCPS), was obtained in the hydrophilized systems. The new copolymers are appropriate for the fabrication of scaffolds with controlled porosity for tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Equivalent potential of water molecules for electronic structure of glutamic acid
Authors: Zhang Tian , Zheng Haoping , Yan Shu 
Published: April 2007

AbstractThe fundamental importance of the electronic structure of molecules is widely recognized. To get reliable electronic structure of protein in aqueous solution, it is necessary to construct a simple, easy‐use equivalent potential of water molecules for protein's electronic structure calculation. Here, the first‐principles, all‐electron, ab initio calculations have been performed to construct the equivalent potential of water molecules for the electronic structure of glutamic acid, which is a hydrophilic amino acid and is negatively charged (Glu−) in neutral water solution. The main process of calculation consists of three steps. Firstly, the geometric structure of the cluster containing Glu− and water molecules is calculated by free cluster calculation. Then, based on the geometric structure, the electronic structure of Glu− with the potential of water molecules is calculated using the self‐consistent cluster‐embedding method. Finally, the electronic structure of Glu− with the potential of dipoles is calculated. Our calculations show that the major effect of water molecules on Glu−'s electronic structure is lowering the occupied electronic states by about 0.017 Ry, and broadening energy gap by 12%. The effect of water molecules on the electronic structure of Glu− can be well simulated by dipoles potential. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Growth format, electronic architecture, magnetic, and optical properties of aromatic cyclo‐Cu3Au3 homotops
Authors: Tsipis Constantinos A. , Depastas Ioannis G. , Kefalidis Christos E. 
Published: April 2007

AbstractBimetallic Cu3Au3 clusters have been investigated using electronic structure calculation techniques (DFT) to understand their electronic, magnetic, and optical properties as well as the geometrical structures. The most stable homotop is the planar cyclo‐[Cu3(μ‐Au)3] form consisting of a triangular positively charged Cu3 structural core with negatively charged Au atoms occupying exposed positions. This structure is characterized by the maximum number of heterobonds and peripheral positions of Au atoms. Possible growth formats of the cyclo‐[Cu3(μ‐Au)3] homotops have been explored following both the edge‐capping and the stepwise metal atom substitution mechanism. The bonding pattern along with the density of states (DOS) plots of the cyclo‐[Cu3(μ‐Au)3] homotop are thoroughly analyzed and compared with those of the pure cyclo‐[Cu3(μ‐Cu)3] and cyclo‐[Au3(μ‐Au)3] clusters. Particular attention was paid on the stability of these bimetallic clusters in relation with the ring‐shaped electron density distribution (aromaticity). It was found that all 3‐membered metal rings exhibit significant aromatic character, which was verified by a number of established criteria of aromaticity, such as structural, energetic, magnetic (NICS profiles), and out‐of‐plane ring deformability criteria. The NICS (1) values correlate well with the out‐of‐plane ring deformation energy. Finally, a comprehensive analysis of the optical spectra of the CuAu, Cu2, and Au2 diatomics and the cyclo‐[Cu3(μ‐Au)3], cyclo‐[Cu3(μ‐Cu)3], and cyclo‐[Au3(μ‐Au)3] clusters placed the electronic assignments of the optical transitions on a firm footing. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Recombinant fusion proteins TAT‐Mu, Mu and Mu‐Mu mediate efficient non‐viral gene delivery
Authors: Rajagopalan Rukkumani , Xavier Jennifer , Rangaraj Nandini , Rao Nalam Madhusudhana , Gopal Vijaya 
Published: April 2007

AbstractBackgroundThe inherent ability of certain peptides or proteins of viral, prokaryotic and eukaryotic origin to bind DNA was used to generate novel peptide‐based DNA delivery protocols. We have developed a recombinant approach to make fusion proteins with motifs for DNA‐binding ability, Mu and membrane transduction domains, TAT, and tested them for their DNA‐binding, uptake and transfection efficiencies. In one of the constructs, the recombinant plasmid was designed to encode the Mu moiety of sequence MRRAHHRRRRASHRRMRGG in‐frame with TAT of sequence YGRKKRRQRRR to generate TAT‐Mu, while the other two constructs, Mu and Mu‐Mu, harbor a single copy or two copies of the Mu moiety.MethodsRecombinant his‐tag fusion proteins TAT‐Mu, Mu and Mu‐Mu were purified by overexpression of plasmid constructs using cobalt‐based affinity resins. The peptides were characterized for their size and interaction with DNA, complexed with plasmid pCMVβ‐gal, and shown to transfect MCF‐7, COS and CHOK‐1 cells efficiently.ResultsRecombinant fusion proteins TAT‐Mu, Mu and Mu‐Mu were cloned and overexpressed in BL21(DE3)pLysS with greater than 95% purity. The molecular weight of TAT‐Mu was determined by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) to be 11.34 kDa while those of Mu and Mu‐Mu were 7.78 and 9.83 kDa, respectively. Live uptake analysis of TAT‐Mu, Mu and Mu‐Mu as DP (DNA + peptide) or DPL (DNA + peptide + lipid) complexes into MCF‐7 cells, followed by immunostaining and laser scanning confocal microscopy, demonstrated that the complexes are internalized very efficiently and localized in the nucleus. DNA : peptide complexes (DP) transfect MCF‐7, COS and CHOK‐1 cells. The addition of cationic liposomes enhances the uptake of the ternary complexes (DPL) further and also brings about 3–7‐fold enhancement in reporter gene expression compared to DP alone.ConclusionsRecombinant proteins that are heterologous fusions, having DNA‐binding domains and nuclear localization epitopes, generated in this study have considerable potential to facilitate DNA delivery and enhance transfection. The domains in these fusion proteins would be promising in the development of non‐viral gene delivery vectors particularly in cells that do not divide. Copyright © 2007 John Wiley & Sons, Ltd.
Hypoxia‐targeted over‐expression of carboxylesterase as a means of increasing tumour sensitivity to irinotecan (CPT‐11)
Authors: Matzow Torkjel , Cowen Rachel L. , Williams Kaye J. , Telfer Brian A. , Flint Pamela J. , Southgate Thomas D. , Saunders Mark P. 
Published: April 2007

AbstractThe induced expression of carboxylesterase (CE) enzymes, which convert the prodrug irinotecan (CPT‐11) into its active cytotoxic metabolite SN‐38, constitutes a promising strategy for cancer gene therapy. By incorporating hypoxia‐responsive elements (HREs) in conjunction with the transgene, expression can be targeted specifically to hypoxic tissues (such as solid tumours), expressing the hypoxia‐inducible factor 1 (HIF‐1). We have constructed a recombinant adenoviral vector, AdHRE‐rCE, encoding the cDNA for the highly efficient rabbit liver CE (rCE), under the control of a HRE derived from the human phosphoglycerate kinase 1 (PGK‐1) gene in conjunction with a minimal SV40 promoter. In vitro, HT1080 fibrosarcoma and SW480 colon carcinoma cells demonstrated an approximately 10‐fold hypoxia‐dependent induction in CE expression following pre‐infection with AdHRE‐rCE, which led to a15–30‐fold increased sensitivity to CPT‐11. Furthermore, in vivo, SW480 tumour xenografts infected with AdHRE‐rCE demonstrated a 2‐fold decrease in tumour doubling time, when combined with 7 days of CPT‐11 treatment, in comparison to mock‐infected controls, with rCE expression shown to be limited to hypoxic regions only. As the cytotoxicity of CPT‐11 is reduced under hypoxic conditions, over‐expression of a highly efficient CE such as rCE under hypoxia control within these hypoxic cells could reverse this effect and, therefore, form the basis for future clinical treatment strategies. Copyright © 2007 John Wiley & Sons, Ltd.
Novel chitosan derivative nanoparticles enhance the immunogenicity of a DNA vaccine encoding hepatitis B virus core antigen in mice
Authors: Jiang Lei , Qian Feng , He Xiaowen , Wang Fang , Ren Ding , He Ying , Li Ka , Sun Shuhan , Yin Chunhua 
Published: April 2007

AbstractBackgroundChitosan has been shown to possess useful properties such as non‐toxicity, high biocompatibility and non‐antigenicity that offer advantages for vaccine delivery systems. In this study, we prepared novel chitosan derivative nanoparticles as DNA vaccine carriers and the potential and mechanism of the DNA‐nanoparticle complexes in inducing augmented immune responses were explored.MethodsThe pVAX(HBc)DNA‐nanoparticle complexes as vaccine delivery systems were studied in several aspects: the protection against DNase I degradation was measured by an in vitro inhibition assay; the sustained expression of the plasmid in vivo was determined by RT‐PCR; the elevated uptake efficiency by phagocytes was observed with confocal microscopy; the biocompatibility was evaluated by cytotoxicity and histology assay; the complexes were administrated to C57BL/6 mice and the humoral and cellular immune responses were evaluated by ELISA, IFN‐γ production and cytolytic T lymphocyte (CTL)‐specific lysis assay.ResultsThe remaining relative activity of DNase I after inhibition varied from 32.3% to 77.6%. The complexes were observed with higher uptake efficiency by phagocytes than naked DNA. Three types of nanoparticles did not induce significant cytotoxicity at concentrations ⩽400 µg/ml. No specific histological alteration related to the injection of the complexes was observed. The formulations of DNA‐nanoparticle complexes significantly enhanced the immunogenicity in several parameters: elevated antibody production, higher level of IFN‐γ secretion, and augmented specific cell lysis.ConclusionsThis study demonstrated the potential of the novel chitosan derivative nanoparticles for safe and effective DNA vaccine delivery. Copyright © 2007 John Wiley & Sons, Ltd.
Long‐term follow‐up of metal‐on‐metal total hip replacement
Authors: Grübl Alexander , Marker Martina , Brodner Wolfram , Giurea Alexander , Heinze Georg , Meisinger Vanee , Zehetgruber Harald , Kotz Rainer 
Published: April 2007

AbstractMetal‐on‐metal articulations were reintroduced to reduce polyethylene particle‐induced osteolysis. Elevated serum metal levels have been detected at short‐ and intermediate‐term follow‐up. There is little knowledge about long‐term effects of increased ionic metal generation. Our study was undertaken to provide information about long‐term survival, clinical outcome, radiographic appearance, and serum metal concentrations after a minimum 10 years follow‐up with a metal‐on‐metal hip prosthesis: 105 cementless primary total hip prostheses with metal‐on‐metal articulating surfaces were implanted in 98 patients with a mean age of 56 years. Clinical data, radiographs, and blood samples were obtained at a follow‐up visit 10 years after implantation. Serum cobalt and chromium levels were determined with use of atomic absorption spectrometry. General laboratory analyses included a full blood count and kidney function parameters. The Harris score was 92 points and the UCLA score 6 points after 10 years. Small osteolytic lesions and radiolucent lines were found in Gruen's zones 1, 7, 8, and 14. The probability of survival was 98.6%. The median serum cobalt concentration of the 22 patients with their hip replacement as the only source of cobalt was 0.75 µg/L (range, 0.3–50.1 µg/L). No patient was diagnosed with renal insufficiency during the study period. Five patients were diagnosed with a malignancy between surgery and the follow‐up. We do not have evidence of an increased rate of primary malignancies nor could we detect renal failure in our study group. Serum metal levels did not differ from short‐ and intermediate term follow‐up values. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:841–848, 2007
Enhanced early chondrogenesis in articular defects following arthroscopic mesenchymal stem cell implantation in an equine model
Authors: Wilke Markus M. , Nydam Daryl V. , Nixon Alan J. 
Published: April 2007

AbstractMesenchymal stem cells (MSCs) provide an important source of pluripotent cells for musculoskeletal tissue repair. This study examined the impact of MSC implantation on cartilage healing characteristics in a large animal model. Twelve full‐thickness 15‐mm cartilage lesions in the femoropatellar articulations of six young mature horses were repaired by injection of a self‐polymerizing autogenous fibrin vehicle containing mesenchymal stem cells, or autogenous fibrin alone in control joints. Arthroscopic second look and defect biopsy was obtained at 30 days, and all animals were euthanized 8 months after repair. Cartilage repair tissue and surrounding cartilage were assessed by histology, histochemistry, collagen type I and type II immunohistochemistry, collagen type II in situ hybridization, and matrix biochemical assays. Arthroscopic scores for MSC‐implanted defects were significantly improved at the 30‐day arthroscopic assessment. Biopsy showed MSC‐implanted defects contained increased fibrous tissue with several defects containing predominantly type II collagen. Long‐term assessment revealed repair tissue filled grafted and control lesions at 8 months, with no significant difference between stem cell‐treated and control defects. Collagen type II and proteoglycan content in MSC‐implanted and control defects were similar. Mesenchymal stem cell grafts improved the early healing response, but did not significantly enhance the long‐term histologic appearance or biochemical composition of full‐thickness cartilage lesions. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:913–925, 2007
Lattice dynamics of tetragonal R2BaCuO5 (R = La, Nd) oxides in the P4/mbm structure
Authors: Gupta H. C. , Sharma V. 
Published: April 2007

AbstractA short‐range force constant model (SRFCM) has been applied to investigate the Raman and the infrared wavenumbers in R2BaCuO5 (R = La, Nd) in their tetragonal phase of space group P4/mbm. Calculations of zone‐center phonons are made with six stretching and five bending force constants. All the Raman and infrared values are then assigned to their corresponding modes. The force constants were evaluated by fitting ten Raman and eight infrared modes. The calculated Raman and infrared modes show good agreement with the observed values. Copyright © 2007 John Wiley & Sons, Ltd.
pH‐dependent surface‐enhanced Raman scattering studies of N‐acetylalanine monolayers self‐assembled on a silver surface
Authors: Yang Haifeng , Zhu Jun , Sheng Chun , Sun Xiaojing , Ji Jiahua , Ma Xiaoling 
Published: April 2007

AbstractMonolayers of N‐acetylalanine on a metallic surface can serve as a biocompatible functional interface to construct biosensors. In the present paper, the surface‐enhanced Raman scattering (SERS) spectra of N‐acetylalanine monolayers self‐assembled on a silver surface under different pH were recorded. Assignments of the obtained spectra were carried out by density functional theory (DFT) calculations (BLYP/6‐311G). On the basis of the SERS effect, the nature of adsorption of N‐acetylalanine on a silver surface was deduced. It can be concluded that the fully protonated N‐acetylalanine is adsorbed on the silver surface via the imine group together with the carboxylate group, while it anchored onto the surface not only through both the imine and the carboxylate groups but also through the amide group after being completely deprotonated in the basic solution. Copyright © 2007 John Wiley & Sons, Ltd.
The linkage between cell wall metabolism and fruit softening: looking to the future
Authors: Vicente Ariel R , Saladié Montserrat , Rose Jocelyn KC , Labavitch John M 
Published: April 2007

AbstractThe softening that accompanies ripening of commercially important fruits exacerbates damage incurred during shipping and handling and increases pathogen susceptibility. Thus, postharvest biologists have studied fruit softening to identify ways to manage ripening and optimise fruit quality. Studies, generally based on the premise that cell wall polysaccharide breakdown causes ripening‐associated softening, have not provided the insights needed to genetically engineer, or selectively breed for, fruits whose softening can be adequately controlled. Herein it is argued that a more holistic view of fruit softening is required. Polysaccharide metabolism is undoubtedly important, but understanding this requires a full appreciation of wall structure and how wall components interact to provide strength. Consideration must be given to wall assembly as well as to wall disassembly. Furthermore, the apoplast must be considered as a developmentally and biochemically distinct, dynamic ‘compartment’, not just the location of the cell wall structural matrix. New analytical approaches for enhancing the ability to understand wall structure and metabolism are discussed. Fruit cells regulate their turgor pressure as well as cell wall integrity as they ripen, and it is proposed that future studies of fruit softening should include attempts to understand the bases of cell‐ and tissue‐level turgor regulation if the goal of optimising softening control is to be reached. Finally, recent studies show that cell wall breakdown provides sugar substrates that fuel other important cellular pathways and processes. These connections must be explored so that optimisation of softening does not lead to decreases in other aspects of fruit quality. Copyright © 2007 Society of Chemical Industry
In vitro gas production profile and the formation of end products from non‐ washable, insoluble washable and soluble washable fractions in some concentrate ingredients
Authors: Azarfar Arash , Williams Barbara A , Boer Huug , Tamminga Seerp 
Published: April 2007

AbstractA procedure that mimics washing in the in situ incubation technique, combined with an in vitro gas and volatile fatty acids (VFAs) production technique, was used to verify the assumption that rumen degradation behaviour of material washed out of nylon bags is instantaneous and complete. In a 6 × 4 factorial arrangement of treatments with three replicates, fractions of maize, barley, milo, yellow peas, lupins (a mixture of white and spotted lupins) and round‐seeded brown faba beans were subjected to an in vitro incubation technique. Fractions were whole (WHO), non‐washable (NWF), insoluble washable (ISWF) and soluble washable (SWF). In a manually operated in vitro fermentation system, another 24 samples of the same substrates were fermented for VFA and ammonia analysis. Except in lupins, ISWF in the concentrate ingredients was very rich in starch. SWF was relatively rich in ash, crude protein, soluble sugars, and a residual unknown fraction but contained only a negligible quantity of starch. Thus, the fermentation characteristics of ISWF were more like WHO and NWF than SWF. Total gas production of SWF was considerably lower than the other fractions. A very rapidly degradable fraction was seen in the first phase of degradation of SWF. The pattern of fermentation end‐product formation for SWF differed from that of the other fractions. Copyright © 2007 Society of Chemical Industry
Uncooked Taiwanese yam (Dioscorea alata L. cv. Tainung No. 2) beneficially modulated the large bowel function and faecal microflora in BALB/c mice
Authors: Wang Cheng‐Hsin , Tsai Chung‐Hung , Lin Hui‐Ju , Wang Tse‐Cheng , Chen Hsiao‐Ling 
Published: April 2007

AbstractThis study investigated the effects of an uncooked Taiwanese yam, Dioscorea alata L. cv. Tainung No. 2, on faecal characteristics, faecal microflora, short‐chain fatty acid (SCFA) levels in the caecal content and faeces, and morphological and proliferation indices of the caecal and colonic crypts in BALB/c mice. Mice were randomly allocated to consume a control diet or a 25 or 50% (w/w) yam diet for 21 days. Faecal wet and dry masses increased with increasing proportions of dietary yam. Both yam diets similarly increased faecal moisture content and decreased faecal pH as compared with the control diet. The yam diets increased total bacteria and bifidobacteria counts and decreased Clostridium perfringens counts in faeces. The 50% yam diet, but not the 25% yam diet, increased total SCFA concentration in the caecal content. However, both yam diets increased total SCFA output in faeces. Both yam diets also promoted crypt depth, width and proliferation indices in the caecum; in contrast, they only promoted crypt width in the distal colon. In conclusion, the 25 and 50% yam diets increased the faecal mass and SCFA output, modulated the faecal microflora and thickened the mucosa lining of the caecum in BALB/c mice. Copyright © 2007 Society of Chemical Industry
The yield and quality of fresh and ensiled plant material from intercropped maize (Zea mays) and beans (Phaseolus vulgaris)
Authors: Dawo Mohamed I , Wilkinson J Michael , Sanders Francis ET , Pilbeam David J 
Published: April 2007

AbstractAn investigation was carried out in the UK to determine whether intercropping with Phaseolus vulgaris beans increases the yield and nutritional quality of maize forage. Fresh and dry yields arising from different sowing dates and different densities of the two species were evaluated, with total nitrogen concentration (TNC) of the plants, and crude protein concentration (CPC), dry matter, metabolizable energy (ME), pH and starch, lactic acid and ash contents of ensiled material. Highest biomass yields of intercrops were obtained when the two species were planted simultaneously. There was a higher TNC in intercropped maize plants than in maize plants grown without beans (P < 0.05). Biomass yields were not significantly higher with a higher density of maize in the intercrop than with a lower density, nor were they higher with monocrop maize than with intercropping. However, the biomass had higher CPC at 75 000 maize plus 50 000 beans ha−1 and 50 000 maize plus 50 000 beans ha−1 than monocrop maize. Other nutritional characteristics of the silage made from the intercrop treatments were not significantly different from those of the silage made from monocrop maize. As the silage from intercrops of 75 000 maize plus 50 000 beans ha−1 and 50 000 maize plus 50 000 beans ha−1 gave more CP per land area than monocrop silage, and gave biomass yields that were not significantly different from monocrop maize, it was concluded that such intercropping is suitable for producing high‐quality silage under similar agro‐climatic conditions. Copyright © 2007 Society of Chemical Industry