bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prenatal ablation of nicotinic receptor alpha7 cell lineages produces lumbosacral spina bifida the severity of which is modified by choline and nicotine exposure
Authors: Rogers Scott W. , Tvrdik Petr , Capecchi Mario R. , Gahring Lorise C. 
Published: April 2012

AbstractLumbosacral spina bifida is a common debilitating birth defect whose multiple causes are poorly understood. Here, we provide the first genetic delineation of cholinergic nicotinic receptor alpha7 (Chrna7) expression and link the ablation of the Chrna7 cell lineage to this condition in the mouse. Using homologous recombination, an IRES‐Cre bi‐cistronic cassette was introduced into the 3′ noncoding region of Chrna7 (Chrna7:Cre) for identifying cell lineages expressing this gene. This lineage first appears at embryonic day E9.0 in rhombomeres 3 and 5 of the neural tube and extends to cell subsets in most tissues by E14.5. Ablation of the Chrna7:Cre cell lineage in embryos from crosses with conditionally expressed attenuated diphtheria toxin results in precise developmental defects including omphalocele (89%) and open spina bifida (SB; 80%). We hypothesized that like humans, this defect would be modified by environmental compounds not only folic acid or choline but also nicotine. Prenatal chronic oral nicotine administration substantially worsened the defect to often include the rostral neural tube. In contrast, supplementation of the maternal diet with 2% choline decreased SB prevalence to 38% and dramatically reduced the defect severity. Folic acid supplementation only trended towards a reduced SB frequency. The omphalocele was unaffected by these interventions. These studies identify the Chrna7 cell lineage as participating in posterior neuropore closure and present a novel model of lower SB that can be substantially modified by the prenatal environment. © 2012 Wiley Periodicals, Inc.
Comparison of two methods of cyclones simulation: semi‐empiric model and CFD. Example of a specific cyclone design
Authors: Bardin‐Monnier N. , Altmeyer S. , Schreiber V. , Marecat A. 
Published: April 2012

ABSTRACTThe aim of this work is to design a cyclone separator, which could reach the highest separation efficiency for fine and low‐density particles (1–10 µm) and air‐flow rates between 10 and 100 L/min. The first part of the study is dedicated to the design, thanks to cyclone software developed by PROGEPI, Nancy, France. It uses classical models and does not take into account the dispersed phase fraction, but allows giving a first approach of the cyclone geometry. Results lead to a Lorenz geometry and pressure drop lower than 10 KPa for 100 L/min. The separation efficiency is never lower than 75% for 2‐µm particles at 50 L/min. In the second part, a computational fluid dynamics study via fluent is conducted in order to determine the performances of the device, thanks to the particle trajectories simulations. Results show that for the higher flow rate (100 L/min), a separation efficiency of 60% is reached for 1‐µm particles. For a lower flow rate (10 L/min), this cyclone is not satisfying because no 1‐µm particles are separated. This study shows that these two approaches are quite complementary in order to reach the most accurate design. Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Optically transparent nanocomposites reinforced with modified biocellulose nanofibers
Authors: Dahman Yaser , Oktem and Tulin 
Published: April 2012

AbstractThe objective of this study is to produce a class of optically transparent nanostructured biocomposites composed of surface‐modified bacterial cellulose (BC) nanofibers reinforced into poly(hydroxyethyl methacrylate) (PHEMA) hydrogel matrix. The surface of BC was first modified by fibrous heterogeneous acetylation to preserve the BC nanofibrillar morphology, followed by graft copolymerization with PHEMA hydrogel by free‐radical mechanisms using benzoyl‐peroxide as a radical initiator. A series of samples of grafted nanofiber having different degrees of acetylation and graft yields were produced and characterized using NMR, FTIR, and gravimetry. The maximum degree of acetylation obtained in this study was 2.3% and the maximum graft yield was 82.35 %.The modified nanofibers were thereafter reinforced into a polymeric matrix of PHEMA to form the final transparent biocomposite. The nanofiber‐network‐reinforced PHEMA polymer composite sample containing 1% (w/w) nanofiber transmitted over 80% of the light, while samples with less than 1% (w/w) nanofibrillar content exhibited higher light transmittances. The loss of transparency in the nanocomposite was small, despite the differences of refractive indices of BC and PHEMA. Increasing content of the BC nanofibers in the composite up to 1.4% (w/w) increased its water holding capacity up to 48.7% compared to the reference sample. This class of transparent nanostructured cellulose‐based hydrogel composite provides unique fluid handling capability of absorption and donation. These characteristics are essential for several applications as optically functional materials in addition to several biomedical applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation and characterization of uniform molecularly imprinted polymer beads for separation of triazine herbicides
Authors: Ara Behisht , Chen Zhiyong , Shah Jasmin , Rasul Jan M. , Ye Lei 
Published: April 2012

AbstractUniform molecularly imprinted polymer beads were synthesized by precipitation polymerization for separation of triazine herbicides. A series of imprinted polymers were prepared using ametryn as template and divinylbenzene as crosslinking monomer, in combination with three different functional monomers under different solvent conditions. Under optimized reaction conditions, we obtained uniform molecularly imprinted polymer microspheres that display favorable molecular binding selectivity for triazine herbicides. The imprinted polymer beads synthesized using methacrylic acid as functional monomer in a mixture of methyl ethyl ketone and heptane showed the best results in terms of particle size distribution and molecular selectivity. Compared with nonimprinted polymer microspheres, the imprinted microspheres displayed significantly higher binding for a group of triazine herbicides including atrazine, simazine, propazine, ametryn, prometryn, and terbutryn. For the first time, precipitation polymerization has been used to produce highly uniform imprinted microspheres suitable for affinity separation of triazine herbicides. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The control of molecular interactions between polyurethane copolymers by grafted malic acid and its impact on polymer characteristics
Authors: Chung Yong‐Chan , Choi Jae Won , Lee Joon Young , Chun Byoung Chul 
Published: April 2012

AbstractMalic acid, a molecule containing two carboxyl groups per molecule, was grafted to polyurethane (PU) through a carbamate group. The polymer was transformed to the anionic carboxylate form to observe the impact on the tensile strength and shape recovery of the PU. The electrostatic repulsion of the carboxylate reduced the molecular interactions between PUs, a result that was designed to improve the shape recovery at sub‐zero temperatures while maintaining high and reproducible tensile strength and shape recovery at ambient temperatures. The grafted carboxyl group was quantitatively determined by acid–base titration, and the change in the molecular interactions was confirmed via IR spectroscopy and differential scanning calorimetry. The viscosity experienced an unusual increase with increasing carboxylate content due to the covalent crosslinking caused by the grafting reagent. Shape recovery and retention were reproducible over repeated shape memory tests. Finally, the shape recovery behavior of each PU was compared at temperatures between −30 and 10°C. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Optimization of reaction conditions for polyurethane foam synthesis with liquefied corn stalk by response surface methodology
Authors: Wang Tipeng , Yin Jun , Zheng Zongming , Mao Zhihuai 
Published: April 2012

AbstractOptimization of copolymerization conditions for biodegradable polyurethane foam with non‐pretreated liquefied corn stalk and polymethylene polyphenylisocyanate was conducted using a quadratic regression rotational combinational design of response surface methodology. A five‐level four‐factor central composite design was employed to determine the maximum tensile strength at optimum levels for [NCO]/[OH] ratio, blowing agent (water), mass ratio of triethylamine (TL)/dibutyltin dilaurate (DD), and surfactant (silicone). The analysis of variance (ANOVA) of the quadratic orthogonal regression model revealed that the fit of the model was good. The model was also verified by experimentation. The maximum tensile strength of 1.64 MPa was obtained at the optimal conditions: [NCO]/[OH] ratio 0.7, blowing agent concentration 4.7 wt %, surfactant concentration 1.27 wt %, and mass ratio of TL/DD 1: 1. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Coumarin‐based polymer and its silver nanocomposite as advanced antibacterial agents: Synthetic path, kinetics of polymerization, and applications
Authors: Srivastava Ambika , Mishra Vivek , Singh Pooja , Kumar Rajesh 
Published: April 2012

AbstractA novel polymer bearing coumarin pendants of 4‐allyloxy‐2H‐chromen‐2‐one (ACO) was synthesized by atom transfer radical polymerization (ATRP) in toluene at 110°C using 2‐Bromoisobutyryl bromide (BIBB), Cu (I) Br, and 2,2′‐bipyridyl (bpy) as initiator, catalyst, and ligand, respectively. The most appropriate molar concentration ratio of [ACO] : [BIBB] : [Cu (I) Br] : [bpy] was found to be 40 : 1 : 1 : 2 for controlled polymerization. Successful chain extension polymerization of poly (4‐allyloxy‐2H‐chromen‐2‐one) (PACO) confirms the livingness of the process. The activation energy (Ea) (76.26 kJ mol−1) and enthalpy of activation (ΔH‡) (73.07 kJ mol−1) were in good agreement to each other proving the feasibility of the reaction and negative value of entropy of activation (ΔS‡) (−320 J mol−1 K−1) supported the highly restricted movement of reacting species in transition state during polymerization. Initial polymer decomposition temperature of PACO was found to be 130°C. SEM analysis revealed that polymer surface is not smooth with pointed rod like shapes. The polymer/Ag nanocomposite was synthesized and examined in view of antibacterial effect against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Proteus mirabilis, and Klebsiella pneumonae. PACO and its Ag nanocomposite (PACON) have been found to be active selectively against bacterial pathogen E. fecalis with minimum inhibitory concentration of 50 and 32 μg mL−1, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Biometry and Statistical Analysis of the Styloid Process
Authors: De Paz Félix JesúS , Rueda s , Barbosa Mercedes , García María , Pastor Juan Francisco 
Published: April 2012

AbstractThe hyoid apparatus is made up of three osteocartilaginous elements that go from the base of the cranium to the hyoid bone; the portions, cranially to caudally, are as follow: stylohyal, ceratohyal, and apohyal. Fusion and ossification of these three components will bring about somewhat long stylohyoid processes, whereas the stylohyal portion is the one that gives rise to the authentic stylohyoid process. The variability of the hyoid apparatus may imply associated compressive pathologies, for which an etiological diagnosis is important. A study was undertaken of 835 craniums of a homogeneous male and female adult population, involving a morphometric analysis of the styloid processes in which quantification was made of the following continual descriptive measurements: thickness, length, sagittal angle, transversal angle, and the distance between vertices. Multivariate data analysis techniques were applied to the data set to describe the relationships between these measurements. The main conclusion from the analysis is the existence of two different groups of styloid processes and the derivation of a prediction score. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Modeling the Human Mandible Under Masticatory Loads: Which Input Variables are Important?
Authors: Gröning Flora , Fagan Michael , O'higgins Paul 
Published: April 2012

AbstractFinite element analyses (FEA) that have simulated masticatory loadings of the human mandible differ significantly with regard to their basic input variables such as material properties, constraints, and applied forces. With sensitivity analyses it is possible to assess how the choice of different input values and the degree of model simplification affect FEA results. However, published FEA studies are rarely accompanied by sensitivity analyses so that the robusticity of their results is impossible to assess. Here, we conduct a sensitivity analysis with an FE model of a human mandible to quantify the relative importance of several modeling decisions: (1) the material properties assigned to the cancellous bone tissue; (2) the inclusion or not of the periodontal ligament; (3) the constraints at the joints and bite point; and (4) the orientation of applied muscle forces. We study the effects of varying these properties by analysing the strain magnitudes and directions across the model surface. In addition, we perform a geometric morphometric analysis of the deformation resulting from the loading of each model. The results show that the effects of altering the different model properties can be significant and that most effects are potentially large enough to cause problems for the biological interpretation of FEA results. We therefore recommend that researchers conduct more sensitivity analyses than at present to assess the robusticity of their FEA results and their biological conclusions. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Design, Synthesis and Evaluation of Novel 2‐(Aminoalkyl)‐isoindoline‐1,3‐dione Derivatives as Dual‐Binding Site Acetylcholinesterase Inhibitors
Authors: Ignasik Michalina , Bajda Marek , Guzior Natalia , Prinz Michaela , Holzgrabe Ulrike , Malawska Barbara 
Published: April 2012

AbstractA new series of 2‐(diethylaminoalkyl)‐isoindoline‐1,3‐dione derivatives intended as dual binding site cholinesterase inhibitors were designed using molecular modeling and evaluated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and the formation of the β‐amyloid (Aβ) plaques. For AChE inhibitory activity, the spectrophotometric method of Ellman and the electrophoretically mediated microanalysis assay were used, giving good results. Most of the synthesized compounds had AChE inhibitory activity with IC50 values ranging from IC50 = 0.9 to 19.5 µM and weak Aβ anti‐aggregation inhibitory activity. These results support the outcome of docking studies which tested compounds targeting both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. The most promising selective AChE inhibitors are compounds 10 (IC50 = 1.2 µM) and 11 (IC50 = 1.1 µM), with 6–7 methylene chains, which also inhibit Aβ fibril formation.
Synthesis, Antitumor, and Antibacterial Activity of Bis[4,5‐diarylimidazol‐2‐ylidene]methane Derivatives
Authors: Liu Wukun , Chen Xiaohua , Gust Ronald 
Published: April 2012

AbstractCationic [bis(1,3‐diethyl‐4,5‐diarylimidazol‐2‐ylidene)]Au(I) bromide complexes have demonstrated considerable potential as new antitumor agents. In order to investigate whether the gold is crucial for the antitumor activity, the imidazole ligands were connected by a methylene bridge. Biological evaluation revealed that bis[1,3‐diethyl‐4,5‐diarylimidazol‐2‐ylidene]methane compounds exhibited growth inhibition effects against mammary (MCF‐7 and MDA‐MB 231) and colon (HT‐29) carcinoma cell lines. In comparison with gold complexes, the methylene derivatives showed drastically reduced cell growth inhibitory properties. However, the growth of bacteria was significantly inhibited by bis[1,3‐diethyl‐4,5‐bis(4‐methoxyphenyl)imidazol‐2‐ylidene]methane dibromide (4) and opens a new application of this compound type.
Untersuchungen zum Einfluss der Klebstoffart auf den kapillaren Wassertransport in Holz parallel zur Faserrichtung
Authors: Mannes David , Schmidt Jon‐Anton , Niemz Peter , Volkmer Thomas 
Published: April 2012

AbstractMittels Neutronenradiographie wurde an verklebten und unverklebten Fichtenholzproben der kapillare Wassertransport in Faserrichtung ermittelt. Bei EPI und 1K‐PUR konnte ein deutlicher Feuchtestau im Bereich der Klebfuge festgestellt werden. Bei Knochenleim, PVAc, UF und MUF trat dieses Verhalten nicht auf oder war weniger ausgeprägt. Die Ergebnisse decken sich mit Messungen zum Diffusionswiderstand von Klebstofffilmen und Holzverklebungen der gleichen Klebstoffe. Die Arbeiten dienen als Grundlage für geplante Finite Elemente (FE)‐Simulationen zum Feuchtetransport in Bauteilen und der Verhinderung von Bauschäden.Investigations on the influence of the adhesive type on the capillary water transport in wood parallel to the fibre direction. The capillary water transport in fibre direction in spruce wood was determined by means of neutron imaging on solid wood samples and samples with one glue line. In the case of EPI and 1C‐PUR a conspicuous moisture accumulation occurred in front of the glue line. This behaviour did not appear with bone glue, PVAc, UF and MUF. The results are conform with investigations of the diffusion resistance made on adhesive films and glued wood with the same adhesive types. The presented work will be the basis of planned Finite Element‐simulations of the moisture transport in glued wood elements and will help to prevent structural damage.
Comparative transcutaneous immunization with imiquimod‐containing ointments and potential of in vitro methods to predict effects
Authors: Gogoll Karsten , Stein Pamela , Wei Hai , Schild Hansjörg , Radsak Markus , Langguth Peter 
Published: April 2012

ABSTRACTThis work evaluates the transcutaneous in vitro and in vivo immunization efficacy of five commercially available 5% imiquimod containing formulations. The parameters included microscopic analysis, rheological properties, drug permeation across synthetic membranes of molecular weight cutoff 10 kDa and ablated murine skin with both 0.1 m HCl and a phthalate buffer pH 3.6 Ph.Eur./methanol 3/7 (v/v) as receiver solutions in a Franz‐diffusion cell model. For in vivo formulation characterization, the cytotoxic T‐cell activity and interferon‐γ production in C57BL/6 mice was determined ex vivo 24 h after transcutaneous administration. OVA257−264 (SIINFEKL) from chicken albumin served as a target antigen.Microscopic images demonstrated differences with respect to the presence or absence of crystalline API. Rheological properties point to a roughly ten‐fold difference between the products at low shear rates. With regard to drug permeation across synthetic membranes, only ‘Nan Bo’ demonstrated equality compared with Aldara™, resulting in f1 and f2 values of 5.25 and 59.58, respectively. The drug permeation rates were maximum from Aldara™ across ablated murine skin. Furthermore, differentiation between the formulations containing crystalline and dissolved states of active imiquimod was possible using this model.The in vivo results yielded significant immunomodulating activities (p < 0.05) of multisource formulations compared with the untreated control group, however, the significance of differences between the formulations was dependent on the parameter of interest.A correlation plot of skin permeation versus in vivo immunostimulating activity yielded a slope significantly different from zero only in the case of the murine skin setup (r between 0.421 and 0.669). Yet this correlation is deemed not satisfactory for formulation optimization. Copyright © 2012 John Wiley & Sons, Ltd.
Optical sensor enabled rocking T‐flasks as novel upstream bioprocessing tools
Authors: Vallejos Jose R. , Micheletti Martina , Brorson Kurt A. , Moreira Antonio R. , Rao Govind 
Published: April 2012

AbstractDuring the past decade, novel disposable cell culture vessels (generally referred to as Process Scouting Devices or PSDs) have become increasingly popular for laboratory scale studies and seed culture generation. However, the lack of engineering characterization and online monitoring tools for PSDs makes it difficult to elucidate their oxygen transfer capabilities. In this study, a mass transfer characterization (kLa) of sensor enabled static and rocking T‐flasks is presented and compared with other non‐instrumented PSDs such as CultiFlask 50®, spinner flasks, and SuperSpinner D 1000®. We have also developed a mass transfer empirical correlation that accounts for the contribution of convection and diffusion to the volumetric mass transfer coefficient (kLa) in rocking T‐flasks. We also carried out a scale‐down study at matched kLa between a rocking T75‐flask and a 10 L (2 L filling volume) wave bioreactor (Cultibag®) and we observed similar DO and pH profiles as well as maximum cell density and protein titer. However, in this scale‐down study, we also observed a negative correlation between cell growth and protein productivity between the rocking T‐flask and the wave bioreactor. We hypothesize that this negative correlation can be due to hydrodynamic stress difference between the rocking T‐flask and the Cultibag. As both cell culture devices share key similarities such as type of agitation (i.e., rocking), oxygen transfer capabilities (i.e., kLa) and disposability, we argue that rocking T‐flasks can be readily integrated with wave bioreactors, making the transition from research‐scale to manufacturing‐scale a seamless process. Biotechnol. Bioeng. 2012;109: 2295–2305. © 2012 Wiley Periodicals, Inc.
Controlling trisulfide modification in recombinant monoclonal antibody produced in fed‐batch cell culture
Authors: Kshirsagar Rashmi , McElearney Kyle , Gilbert Alan , Sinacore Marty , Ryll Thomas 
Published: April 2012

AbstractMolecular heterogeneity was detected in a recombinant monoclonal antibody (IgG1 mAb) due to the presence of a trisulfide linkage generated by the post‐translational insertion of a sulfur atom into disulfide bonds at the heavy–heavy and heavy–light junctions. This molecular heterogeneity had no observable effect on antibody function. Nevertheless, to minimize the heterogeneity of the IgG1 mAb from run‐to‐run, an understanding of the impact of cell culture process conditions on trisulfide versus disulfide linkage formation was desirable. To investigate variables that might impact trisulfide formation, cell culture parameters were varied in bench‐scale bioreactor studies. Trisulfide analysis of the samples from these runs revealed that the trisulfide content in the bond between heavy and light chains varied considerably from <1% to 39%. Optimizing the culture duration and feeding strategy resulted in more consistent trisulfide levels. Cysteine concentration in the feed medium had a direct correlation with the trisulfide level in the product. Systematic studies revealed that cysteine in the feed and the bioreactor media was contributing hydrogen sulfide which reacted with the IgG1 mAb in the supernatant leading to the insertion of sulfur atom and formation of a trisulfide bond. Cysteine feed strategies were developed to control the trisulfide modification in the recombinant monoclonal antibody. Biotechnol. Bioeng. 2012; 109: 2523–2532. © 2012 Wiley Periodicals, Inc.