bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hybrid expression cassettes consisting of a milk protein promoter and a cytomegalovirus enhancer significantly increase mammary‐specific expression of human lactoferrin in transgenic mice
Authors: Cheng Yong , An Li‐you , Yuan Yu‐Guo , Wang Yi , Du Fu‐Liang , Yu Bao‐Li , Zhang Zheng‐Hong , Huang Yu‐Zheng , Yang Ting‐Jia 
Published: June 2012

AbstractIt is very important to develop an effective, specific, and robust expression cassette that ensures a high level of expression in the mammary glands. In this study, we designed and constructed a series of mammary gland‐specific vectors containing a complex hybrid promoter/enhancer by utilizing promoter sequences from milk proteins (i.e., goat β‐casein, bovine αs1‐casein, or goat β‐lactoglobulin) and cytomegalovirus enhancer sequences; vectors containing a single milk protein promoter served as controls. Chicken β‐globin insulator sequences were also included in some of these vectors. The expression of constructs was analyzed through the generation of transgenic mice. Enzyme‐linked immunosorbent assay (ELISA) analysis revealed that the hybrid promoter/enhancer could drive the expression of recombinant human lactoferrin (rhLF) cDNA at high levels (1.17–8.10 mg/ml) in the milk of transgenic mice, whereas control promoters achieved a very low rhLF expression (7–40 ng/ml). Moreover, the expression of rhLF was not detected in the serum or saliva of any transgenic animal. This result shows that all constructs, driven by the hybrid promoter/enhancer, had high mammary gland‐specific expression pattern. Together, our results suggest that the use of a hybrid promoter/enhancer is a valuable alternative approach for increasing mammary‐specific expression of recombinant hLF in a transgenic mouse model.Mol. Reprod. Dev. 79: 573‐585, 2012. © 2012 Wiley Periodicals, Inc.
Intramuscular adipose tissue and central activation in older adults
Authors: Yoshida Yuri , Marcus Robin L. , Lastayo Paul C. 
Published: June 2012

AbstractIntroduction: Intramuscular adipose tissue (IMAT) is a potential contributor to declining force production and may be related to impaired central activation; therefore, the purpose of this report is to describe IMAT composition and its association with central activation in older adults. The central activation ratio (CAR) of the knee extensors was assessed using a superimposition technique in 15 older adults (29 legs) along with the cross‐sectional area of IMAT and lean tissue. Results: IMAT and CAR are inversely related in older adults (r = −0.51, P = 0.005), and many subjects with high IMAT have deficits in central activation, whereas those with low IMAT have normal central activation. Conclusions: These novel findings may assist in unraveling why muscle force production and lean tissue cross‐sectional area are not strongly linked, as the ability to centrally activate muscle appears to be unrelated to lean muscle area and may be dependent in part on IMAT levels. Muscle Nerve 46:813–816, 2012
Combined Eulerian–PFEM approach for analysis of polymers in fire situations
Authors: Marti J. , Ryzhakov P. , Idelsohn S. , Oñate E. 
Published: June 2012

SUMMARYIn this paper, we present a computational algorithm for solving an important practical problem, namely, the thermoplastic polymer melting under fire conditions. We propose here a technique that aims at minimizing the computational cost. This is basically achieved by using the immersed boundary‐like approach, combining the particle finite element method for the polymer with an Eulerian formulation for the ambience. The polymer and ambience domains interact over the interface boundary. The boundary is explicitly defined by the position of the Lagrangian domain (polymer) within the background Eulerian mesh (ambience). This allows to solve the energy equation for both subdomains on the Eulerian mesh with different thermal properties. Radiative transport equation is exclusively considered for the ambience, and the heat exchange at the interface is modeled by calculating the radiant heat flux and imposing it as a natural boundary condition. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of fiber weight fraction on mechanical properties of carbon–carbon composites
Authors: Naik Padmayya Shaniyara , Orangalu Surendranathan Attakuli , Londhe Neelakantha V. 
Published: June 2012

AbstractThis article presents the synthesis of carbon–carbon (C/C) composites by preformed yarn (PY) method, by varying the percentage of carbon fiber weight fraction. The PY used was carbon fiber bundle surrounded by coke and pitch which was enclosed in nylon‐6. Three types of samples with fiber weight fractions of 30, 40, and 50%, respectively, are fabricated and mechanical properties were studied. In each case, the PY was chopped and filled into a die of required shape and hot pressed at 500°C to get the preform composite. To obtain the carbonized and graphitic structure, the specimen was heat treated at 2500°C followed by soaking for 10 to 12 hrs. Further, two cycles pitch impregnation was done by hot isostatic pressing, to eliminate the voids and to increase the density hence to obtain good mechanical properties. The characteristics such as hardness, flexural strength, and impact strengths were studied. It is observed that, as the carbon fiber percentage increases, the properties also get improved, provided sintering is done at fairly higher temperatures such as 2700°C. The superiority of the new class of C/C composites made by the proposed PY technique over those obtained by the conventional methods is also demonstrated. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Tribological properties of ethylene–propylene–diene rubber + polypropylene + thermal‐shock‐resistant ceramic composites
Authors: Brostow Witold , Datashvili Tea , Geodakyan James 
Published: June 2012

AbstractThis work is part of a program on composites used in thermoelectric devices. Tribological properties of dynamic vulcanizate blends of polypropylene and ethylene‐propylene‐diene rubber filled with 5 wt% of microscale powder have been studied. The microscale thermal‐shock‐resistant ceramic filler contains α‐Al2O3, mullite (3Al2O3 · 2SiO2 or 2Al2O3SiO2), β‐spodumene glass‐ceramic and aluminium titanate. We found that our ceramic particles are abrasive; they cause strong abrasion of softer steel ball surfaces during dry sliding friction. To overcome the difficulty of particle dispersion and adhesion, the filler was modified through grafting using three types of organic molecules. Dry sliding friction was measured using four types of counter‐surfaces: tungsten carbide, Si3N2, 302 steel and 440 steel. Thermoplastic vulcanizate filled with neat ceramic powder shows the lowest friction compared to composites containing the same but surface‐treated powder. We introduce a ‘bump’ model to explain the tribological responses of our composites. ‘Naked’ or untreated ceramic particles protrude from the polymer surface and cause a decrease of the contact area compared to neat polymer. The ball partner surface has only a small contact area with the bumps. As contact surface area decreases, so does friction and the amount of heat generated during sliding friction testing. Chemical coupling of the ceramic to the matrix smoothens the bumps and increases the contact surface, giving a parallel increase in friction. Copyright © 2012 Society of Chemical Industry
Design of conduction band structure of TiO2 electrode using Nb doping for highly efficient dye‐sensitized solar cells
Authors: Tsvetkov Nikolay A. , Larina Liudmila L. , Shevaleevskiy Oleg , Al‐Ammar Essam A. , Ahn Byung Tae 
Published: June 2012

ABSTRACTA barrier layer of undoped TiO2 was deposited on the Nb‐doped TiO2 electrode to suppress the recombination at the Nb‐doped TiO2/dye–electrolyte interface for highly efficient dye‐sensitized solar cells (DSCs). The Nb content in TiO2 was varied in a range of 0.7–3.5 mol% to modify the TiO2 energy‐band structure. Nb‐doped TiO2/dye interfaces were characterized by a combination of ultraviolet photoemission spectroscopy and optical absorption spectroscopy measurements, allowing the determination of the conduction band minimum (CBM) of the TiO2 electrode and the lowest unoccupied molecular orbital of the N719 dye. The lowering of TiO2 CBM by Nb doping induced the increase in short‐circuit current of DSCs. However, open‐circuit voltage and fill factor are decreased, and this result was ascribed to the enhanced recombination at the Nb‐doped TiO2/dye–electrolyte interface. The effect of doping on charge transport in DSCs was analyzed using electrochemical impedance spectroscopy. We have shown that by introducing of TiO2 barrier layer, the Nb doping content, which results in DSC highest efficiency, can be increased because of the suppression of the dopant‐induced recombination. The energy conversion efficiency of the solar cells increased from 7.8% to 9.0% when undoped TiO2 electrode is replaced with electrode doped with 2.7 mol% of Nb because of the improvement of the electron injection and collection efficiencies. The correlation between the electronic structure of the TiO2 electrode, charge transfer characteristics, and photovoltaic parameters of DSCs is discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Brane singularities with mixtures in the bulk
Authors: Antoniadis I. , Cotsakis S. , Klaoudatou I. 
Published: June 2012

AbstractBy extending previous analysis of the authors, a systematic study of the singularity structure and possible asymptotic behaviors of five‐dimensional braneworld solutions is performed in the case where the bulk is a mixture of an analog of perfect fluid (with a density and pressure depending on the extra coordinate) and a massless scalar field. The two bulk components interact by exchanging energy so that the total energy is conserved. In a particular range of the interaction parameters, we find flat brane general solutions avoiding the singularity at finite distance from the brane, in the same region of the equation of state constant parameter γ = P/ρ that we found previously in the absence of the bulk scalar field (‐1 < γ < ‐1/2).
Unified treatment of exactly solvable quantum potentials with confluent hypergeometric eigenfunctions: Generalized potentials
Authors: Peña J. J. , Morales J. , García‐Martínez J. , García‐Ravelo J. 
Published: June 2012

AbstractIn this work, we propose an alternative approach to transform a general second‐order differential equation (DE) into a Schrödinger‐like equation. As a useful application of the proposal, we consider explicitly the case of the confluent hypergeometric (CH) DE with the aim to unify all potentials having CH eigenfunctions. That is, the proposed approach allows us to obtain generalized potential models that contain as particular cases the standard exactly solvable potentials with CH solutions such as the one‐ and three‐dimensional Harmonic, Morse, Coulomb, and other well known potentials. Besides, due that the proposed method is general, it can be straightforwardly applied to other DE in the search of bound‐states solutions for new potential models that could be useful in quantum chemistry. © 2012 Wiley Periodicals, Inc.
Microsolvation effects on the stability of polyalanine in extended and polyproline II conformation
Authors: Ireta Joel 
Published: June 2012

AbstractMicrosolvation of a polyalanine chain in a fully extended structure (FES) and polyproline II conformation (PP‐II) is studied using density functional theory. Infinitely long systems are investigated to form infinite networks of hydrogen bonds (hbs) along the microsolvation shells. In this manner hbs cooperative effect is evaluated. The stability of microsolvated PP‐II respect to microsolvated FES is investigated by changing the number of adsorbed water molecules per residue (nw) from 2 to 11. It is found that PP‐II stability strongly depends on the nw value. For example, PP‐II is more stable respect to FES by ∼14 kcal/mol for nw = 9, however its stability drops to ∼4 kcal/mol for nw = 10. It is shown that such behavior is connected to cooperative effects at the hydration shell, where water‐water hbs strengthen up to 46%. Besides backbone‐water hbs weaken, most notably in FES where its strength is diminished by 36%. Such interplay between water‐water and backbone‐water hydrogen bonding leads to a marginal stability of PP‐II respect to FES for nw ≥ 10. © 2012 Wiley Periodicals, Inc.
Worldwide proficiency test for routine analysis of δ2H and δ18O in water by isotope‐ratio mass spectrometry and laser absorption spectroscopy
Authors: Wassenaar L. I. , Ahmad M. , Aggarwal P. , van Duren M. , Pöltenstein L. , Araguas L. , Kurttas T. 
Published: June 2012

RATIONALEThe interpretation of stable hydrogen and oxygen isotope data in isotope hydrology relies on accurate, high‐precision analytical measurements of the 2H:1H and 18O:16O ratios in liquid H2O samples.METHODSA synthesis of the International Atomic Energy Agency (IAEA) worldwide proficiency test for analytical laboratories conducting routine analysis of δ2H and δ18O values in water (WICO2011) by isotope‐ratio mass spectrometry (IRMS) and laser absorption spectroscopy (LAS) technology has been carried out.RESULTSThis test revealed that >96% of the 160 laboratory submissions provided acceptable results within ±2‰ for δ2H values and ±0.2‰ for δ18O values of the established reference values for four test waters, and no difference in outcomes based on IRMS vs. LAS technology was found for good performing laboratories.CONCLUSIONSThe leading cause of outliers appeared to be improper calibration or compromised storage of laboratory standard and primary reference waters; hence the importance of judicious storage of lab standards cannot be understated. The deprecated practice of single standard normalization was identified as a problem for some laboratories. We further recommend that laboratories strive to report parsimonious long‐term precisions based upon control standards, and to improve quantification and correction for LAS instrumental drift and inter‐sample carryover effects. Copyright © 2012 John Wiley & Sons, Ltd.
Gas‐phase behaviour of Ru(II) cyclopentadienyl‐derived complexes with N‐coordinated ligands by electrospray ionization mass spectrometry: fragmentation pathways and energetics
Authors: Madeira Paulo J. Amorim , Morais Tânia S. , Silva Tiago J. L. , Florindo Pedro , Garcia M. Helena 
Published: June 2012

RATIONALEThe gas‐phase behaviour of six Ru(II) cyclopentadienyl‐derived complexes with N‐coordinated ligands, compounds with antitumor activities against several cancer lines, was studied. This was performed with the intent of establishing fragmentation pathways and to determine the Ru–LN and Ru–LP ligand bond dissociation energies. Such knowledge can be an important tool for the postulation of the mechanisms of action of these anticancer drugs.METHODSTwo types of instruments equipped with electrospray ionisation were used (ion trap and a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer). The dissociation energies were determined using energy‐variable collision‐induced dissociation measurements in the ion trap. The FTICR instrument was used to perform MSn experiments on one of the compounds and to obtain accurate mass measurements. Theoretical calculations were performed at the density functional theory (DFT) level using two different functionals (B3LYP and M06L) to estimate the dissociation energies of the complexes under study.RESULTSThe influence of the LN on the bond dissociation energy (D) of RuCp compounds with different nitrogen ligands was studied. The lability order of LN was: imidazole < 1‐butylimidazole < 5‐phenyl‐1H‐tetrazole < 1‐benzylimidazole. Both the functionals used gave the following ligand lability order: imidazole < 1‐benzylimidazole < 5‐phenyl‐1H‐tetrazole < 1‐butylimidazole. It is clear that there is an inversion between 1‐benzylimidazole and 1‐butylimidazole for the experimental and theoretical lability orders. The M06L functional afforded values of D closer to the experimental values. The type of phosphane (LP) influenced the dissociation energies, with values of D being higher for Ru–LN with 1‐butylimidazole when the phosphane was 1,2‐bis(diphenylphosphino)ethane. The Ru–LP bond dissociation energy for triphenylphosphane was independent of the type of complex.CONCLUSIONSThe D values of Ru–LN and Ru–LP were determined for all six compounds and compared with the values calculated by the DFT method. For the imidazole‐derived ligands the energy trend was rationalized in terms of the increasing extension of the σ‐donation/π‐backdonation effect. The bond dissociation energy of Ru–PPh3 was independent of the fragmentations. Copyright © 2012 John Wiley & Sons, Ltd.
Atmospheric pressure photoionization mass spectrometry as a valuable method for the identification of polyisoprenoid alcohols
Authors: Kania Magdalena , Skorupinska‐Tudek Karolina , Swiezewska Ewa , Danikiewicz Witold 
Published: June 2012

RATIONALEThe aim of this study was to determine whether Atmospheric Pressure Photoionization (APPI) was better suited for the mass spectrometric (MS) analysis of polyisoprenoid alcohols than the commonly used Electrospray Ionization (ESI) method. The APPI method should make possible the use of non‐polar solvents without any of the additives required by ESI, together with improved detection limits.METHODSThe liquid chromatography (LC)/APPI‐MS and LC/ESI‐MS spectra of polyisoprenoid alcohol standards were acquired in both positive and negative ion mode, in methanol and hexane, using a triple quadrupole/linear ion trap tandem mass spectrometer equipped with both an ESI and an APPI ion source.RESULTSIn the positive ion mode peaks corresponding to [M + H − H2O]+ and [M + H]+ ions were observed in the APPI‐MS spectra of polyprenols and dolichols, respectively. In the negative ion mode peaks corresponding to [M + O2]−• and [M + Cl]− ions were observed for both classes of polyisoprenoid alcohols. The detection limit of polyisoprenoid alcohols was established at the level of 10 pg.CONCLUSIONSAPPI turned out to be a method of choice for the identification and quantitation of polyisoprenoid alcohols by MS using both polar and non‐polar solvents. APPI also enabled greater differentiation of polyprenols and dolichols occurring together in natural samples and gave much better TIC chromatograms without the need for the post‐column salt addition required by ESI. Copyright © 2012 John Wiley & Sons, Ltd.
Donor Satellite Cell Engraftment Is SignificantlyAugmented When the Host Niche Is Preserved and Endogenous Satellite Cells Are Incapacitated
Authors: Boldrin Luisa , Neal Alice , Zammit Peter S. , Muntoni Francesco , Morgan Jennifer E. 
Published: June 2012

Abstract
Stem cell transplantation is already in clinical practice for certain genetic diseases and is a promising therapy for dystrophic muscle. We used the mdx mouse model of Duchenne muscular dystrophy to investigate the effect of the host satellite cell niche on the contribution of donor muscle stem cells (satellite cells) to muscle regeneration. We found that incapacitation of the host satellite cells and preservation of the muscle niche promote donor satellite cell contribution to muscle regeneration and functional reconstitution of the satellite cell compartment. But, if the host niche is not promptly refilled, or is filled by competent host satellite cells, it becomes nonfunctional and donor engraftment is negligible. Application of this regimen to aged host muscles also promotes efficient regeneration from aged donor satellite cells. In contrast, if the niche is destroyed, yet host satellite cells remain proliferation-competent, donor-derived engraftment is trivial. Thus preservation of the satellite cell niche, concomitant with functional impairment of the majority of satellite cells within dystrophic human muscles, may improve the efficiency of stem cell therapy.
Subspace clustering
Authors: Kriegel Hans‐Peter , Kröger Peer , Zimek Arthur 
Published: June 2012

AbstractSubspace clusteringrefers to the task of identifying clusters of similar objects or data records (vectors) where the similarity is defined with respect to a subset of the attributes (i.e., a subspace of the data space). The subspace is not necessarily (and actually is usually not) the same for different clusters within one clustering solution. In this article, the problems motivating subspace clustering are sketched, different definitions and usages of subspaces for clustering are described, and exemplary algorithmic solutions are discussed. Finally, we sketch current research directions. © 2012 Wiley Periodicals, Inc.This article is categorized under:Technologies > Structure Discovery and Clustering
Clustering high dimensional data
Authors: Assent Ira 
Published: June 2012

AbstractHigh‐dimensional data, i.e., data described by a large number of attributes, pose specific challenges to clustering. The so‐called ‘curse of dimensionality’, coined originally to describe the general increase in complexity of various computational problems as dimensionality increases, is known to render traditional clustering algorithms ineffective. The curse of dimensionality, among other effects, means that with increasing number of dimensions, a loss of meaningful differentiation between similar and dissimilar objects is observed. As high‐dimensional objects appear almost alike, new approaches for clustering are required. Consequently, recent research has focused on developing techniques and clustering algorithms specifically for high‐dimensional data. Still, open research issues remain. Clustering is a data mining task devoted to the automatic grouping of data based on mutual similarity. Each cluster groups objects that are similar to one another, whereas dissimilar objects are assigned to different clusters, possibly separating out noise. In this manner, clusters describe the data structure in an unsupervised manner, i.e., without the need for class labels. A number of clustering paradigms exist that provide different cluster models and different algorithmic approaches for cluster detection. Common to all approaches is the fact that they require some underlying assessment of similarity between data objects. In this article, we provide an overview of the effects of high‐dimensional spaces, and their implications for different clustering paradigms. We review models and algorithms that address clustering in high dimensions, with pointers to the literature, and sketch open research issues. We conclude with a summary of the state of the art. © 2012 Wiley Periodicals, Inc.This article is categorized under:Technologies > Structure Discovery and Clustering
Optimization of ordered plasmid assembly by gap repair in Saccharomyces cerevisiae
Authors: Eckert‐Boulet Nadine , Pedersen Mette Louise , Krogh Berit Olsen , Lisby Michael 
Published: June 2012

AbstractCombinatorial genetic libraries are powerful tools for diversifying and optimizing biomolecules. The process of library assembly is a major limiting factor for library complexity and quality. Gap repair by homologous recombination in Saccharomyces cerevisiae can facilitate in vivo assembly of DNA fragments sharing short patches of sequence homology, thereby supporting generation of high‐complexity libraries without compromising fidelity. In this study, we have optimized the ordered assembly of three DNA fragments into a gapped vector by in vivo homologous recombination. Assembly is achieved by co‐transformation of the DNA fragments and the gapped vector, using a modified lithium acetate protocol. The optimal gap‐repair efficiency is found at a 1:80 molar ratio of gapped vector to each of the three fragments. We measured gap‐repair efficiency in different genetic backgrounds and observed increased efficiency in mutants carrying a deletion of the SGS1 helicase‐encoding gene. Using our experimental conditions, a gap‐repair efficiency of > 106 plasmid‐harbouring colonies/µg gapped vector DNA is obtained in a single transformation, with a recombination fidelity > 90%. Copyright © 2012 John Wiley & Sons, Ltd.