bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlating Emissive Non‐Geminate Charge Recombination with Photocurrent Generation Efficiency in Polymer/Perylene Diimide Organic Photovoltaic Blend Films
Authors: Keivanidis Panagiotis E. , Kamm Valentin , Zhang Weimin , Floudas George , Laquai Frédéric , McCulloch Iain , Bradley Donal D. C. , Nelson Jenny 
Published: March 2012

AbstractEvidence for a correlation between the dynamics of emissive non‐geminate charge recombination within organic photovoltaic (OPV) blend films and the photocurrent generation efficiency of the corresponding blend‐based solar cells is presented. Two model OPV systems that consist of binary blends of electron acceptor N′‐bis(1‐ethylpropyl)‐3,4,9,10‐perylene tetracarboxy diimide (PDI) with either poly(9,9‐dioctylfluorene‐co‐benzothiadiazole) (F8BT) or poly(9,9‐dioctylindenofluorene‐co‐benzothiadiazole) (PIF8BT) as electron donor are studied. For the F8BT:PDI and PIF8BT:PDI devices photocurrent generation efficiency is shown to be related to the PDI crystallinity. In contrast to the F8BT:PDI system, thermal annealing of the PIF8BT:PDI layer at 90 °C has a positive impact on the photocurrent generation efficiency and yields a corresponding increase in PL quenching. The devices of both blends have a strongly reduced photocurrent on higher temperature annealing at 120 °C. Delayed luminescence spectroscopy suggests that the improved efficiency of photocurrent generation for the 90 °C annealed PIF8BT:PDI layer is a result of optimized transport of the photogenerated charge‐carriers as well as of enhanced PL quenching due to the maintenance of optimized polymer/PDI interfaces. The studies propose that charge transport in the blend films can be indirectly monitored from the recombination dynamics of free carriers that cause the delayed luminescence. For the F8BT:PDI and PIF8BT:PDI blend films these dynamics are best described by a power‐law decay function and are found to be temperature dependent.
Incipient Ferroelectricity in Al‐Doped HfO2 Thin Films
Authors: Mueller Stefan , Mueller Johannes , Singh Aarti , Riedel Stefan , Sundqvist Jonas , Schroeder Uwe , Mikolajick Thomas 
Published: March 2012

AbstractIncipient ferroelectricity is known to occur in perovskites such as SrTiO3, KTaO3, and CaTiO3. For the first time it is shown that the intensively researched HfO2 thin films (16 nm) also possess ferroelectric properties when aluminium is incorporated into the host lattice. Polarization measurements on Al:HfO2 based metal–insulator–metal capacitors show an antiferroelectric‐to‐ferroelectric phase transition depending on annealing conditions and aluminium content. Structural investigation of the electrically characterized capacitors by grazing incidence X‐ray diffraction is presented in order to gain further insight on the potential origin of ferroelectricity. The non‐centrosymmetry of the elementary cell, which is essential for ferroelectricity, is assumed to originate from an orthorhombic phase of space group Pbc21 stabilized for low Al doping in HfO2. The ferroelectric properties of the modified HfO2 thin films yield high potential for various ferroelectric, piezoelectric, and pyroelectric applications. Furthermore, due to the extensive knowledge accumulated by various research groups regarding the HfO2 dielectric, an immediate relevance of ferroelectric hafnium oxide thin films is anticipated by the authors.
Arynes and Cyclohexyne in Natural Product Synthesis
Authors: Gampe Christian M. , Carreira Erick M. 
Published: March 2012

AbstractThis Minireview highlights recent advances in the field of aryne and cyclohexyne chemistry that have allowed the extraordinary reactivity of these entities to be harnessed during the course of natural product syntheses. The syntheses presented rely on the use of these reactive species in chemoselective transformations and follow unprecedented synthetic strategies that are inspiring for the practitioners of synthetic organic chemistry.
Effect of nanoclay type on dyeability of polyethylene terephthalate/clay nanocomposites
Authors: Parvinzadeh Gashti Mazeyar , Moradian Siamak 
Published: March 2012

AbstractPolyethylene terephthalate (PET)‐based nanocomposites containing three differently modified clays were prepared by melt compounding. The influence of type of clay on disperseability, thermal, and dyeing properties of the resultant nanocomposite was investigated by various analytic techniques, namely, X‐ray diffraction, optical microscopy (OPM), differential scanning calorimetry, thermal gravimetric analysis, dynamical mechanical thermal analysis, contact angle measurement (CAM), reflectance spectroscopy, and light fastness. OPM images illustrated formation of large‐sized spherulites in pure PET, while only small‐sized crystals appeared in PET/clay nanocomposites. Decreased glass transition temperatures for all PET/clay nanocomposites indicate that the amorphous regions of such composites become mobile at lower temperatures than those in pure PET. CAMs on the resultant PET composites demonstrated that the wettability of such composites depends on hydrophilicity of the nanoclay particles. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effects of 3,4′‐oxydianiline on the structures and properties of a novel aromatic polyimide foam
Authors: Li Yin , Liu Xiao‐Yan , Zhan Mao‐Sheng , Wang Kai 
Published: March 2012

AbstractAiming at the low volumetric shrinkage, a novel aromatic polyimide foam is successfully prepared from polymethane polyphenyl isocyanate (PAPI) and a poly(amic‐acid) precursor which has been synthesized from 3,4′‐oxydianiline (3,4′‐ODA) and pyromellitic dianhydride (PMDA). In this research, five polyimide foams, with different contents of 3,4′‐ODA, are comparatively studied including structural, thermal, mechanical, shrink, and degradation properties. The results indicate that the content of 3,4′‐ODA has minor influence on chemical structures, but significant influence on cell structures of the foams. With the increase of 3,4′‐ODA, the volumetric shrinkages, apparent densities and the compressive and flatwise tensile strengths of the materials decrease. The glass transition temperatures (Tg) decrease from 301°C to 279°C, and the 5% weight loss temperatures (T5%) increase from 323°C to 340°C. Through TG‐FTIR analysis, we can observe that the addition of 3,4′‐ODA has no influence on the pyrolysis mechanism of polyimide foams. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Influence of Mesterolone on Satellite Cell Distribution and Fiber Morphology within Maturing Chicken Pectoralis Muscle
Authors: Allouh Mohammed Z. , Aldirawi Mohammed H. 
Published: March 2012

AbstractMesterolone is a synthetic oral anabolic androgenic steroid used to treat hypogonadism. There are frequent reports of mesterolone abuse in human and equine sports to increase muscle mass and strength. However, limited information is available about how this drug exerts its effects on skeletal muscle. Satellite cells (SCs) are mononuclear myogenic stem cells that contribute to postnatal muscle growth and repair. As SC activation and subsequent differentiation to new myonuclei is a major event during muscle hypertrophy, this study investigated the influence of mesterolone on SC distribution within the pectoralis muscle of chickens. Specifically, this study tested the hypotheses that mesterolone induces avian skeletal muscle hypertrophy, and that mesterolone increases the number of SCs in avian skeletal muscle. Robust immunocytochemical techniques and morphometric analyses were used to calculate the numbers of SCs and myonuclei. Also, DNA concentration and Pax7 protein levels were measured to confirm immunocytochemical findings. Mesterolone significantly increased pectoralis mass and fiber size. All SC indices and number of myonuclei increased significantly by mesterolone administration. In addition, greater DNA concentration and Pax7 protein expression were found in mesterolone‐treated birds. This study indicates that mesterolone can induce avian skeletal muscle hypertrophy and that this is correlated with increased number of SCs. We suggest that SCs are key cellular intermediaries for mesterolone‐induced muscle hypertrophy. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
An Experimental Approach to Evaluate the Correspondence Between Wear Facet Position and Occlusal Movements
Authors: Kullmer Ottmar , Schulz Dieter , Benazzi Stefano 
Published: March 2012

AbstractThe position of dental wear facets depends on crown morphology, antagonistic relation, and occlusal movements. The correspondence between specific directions of movements and the position of wear facets cannot be easily evaluated in vivo and has never been tested experimentally. An experimental analysis was carried out to provide evidence that explicit occlusal movements are responsible for the spatial position of wears facets. Unworn dental stone replicas of modern human prosthetic molar were mounted in a physical dental articulator, and the upper dental arch was ground against the lowers to create a wear facet pattern. The relief guided movements were constrained sequentially by means of three different condyle box setups: (1) experienced‐based mean values for sagittal condyle inclination, lateroretrusion, Benett angle, and transversal condyle inclination were used; (2) pure retrusion and immediate side shift movements were added; (3) retrusion and immediate side shift were increased. Finally, the upper and lower first molars were surface scanned and macrowear facets were quantified in four wear stages. The results show that a wear facet pattern was created similar to what is seen on human molars in vivo occlusion. Some facets only developed if specific directions of movement were carried out. Therefore, we posit that an analysis of wear facet patterns is useful in recreating the individual occlusal movements. This information can be used not only to guide reproducible functional reconstructions of crown relief and dental arches but also to deduce jaw movements when, for example, isolated primate teeth are discovered in paleontological contexts. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Conditional activation of β‐catenin signaling in mice leads to severe defects in intervertebral disc tissue
Authors: Wang Meina , Tang Dezhi , Shu Bing , Wang Baoli , Jin Hongting , Hao Suyang , Dresser Karen A. , Shen Jie , Im Hee‐Jeong , Sampson Erik R. , Rubery Paul T. , Zuscik Michael J. , Schwarz Edward M. , O'Keefe Regis J. , Wang Yongjun , Chen Di 
Published: March 2012

AbstractObjectiveThe incidence of low back pain is extremely high and is often linked to intervertebral disc (IVD) degeneration. The mechanism of this disease is currently unknown. This study was undertaken to investigate the role of β‐catenin signaling in IVD tissue function.Methodsβ‐catenin protein levels were measured by immunohistochemical analysis of disc samples obtained from patients with disc degeneration and from normal subjects. To generate β‐catenin conditional activation (cAct) mice, Col2a1‐CreERT2–transgenic mice were bred with β‐cateninfx(Ex3)/fx(Ex3) mice. Changes in disc tissue morphology and function were examined by micro–computed tomography, histologic analysis, and real‐time polymerase chain reaction assays.Resultsβ‐catenin protein was up‐regulated in disc tissue samples from patients with disc degeneration. To assess the effects of increased β‐catenin levels on disc tissue, we generated β‐catenin cAct mice. Overexpression of β‐catenin in disc cells led to extensive osteophyte formation in 3‐ and 6‐month‐old β‐catenin cAct mice, which were associated with significant changes in the cells and extracellular matrix of disc tissue and growth plate. Gene expression analysis demonstrated that activation of β‐catenin enhanced runt‐related transcription factor 2–dependent Mmp13 and Adamts5 expression. Moreover, genetic ablation of Mmp13 or Adamts5 on the β‐catenin cAct background, or treatment of β‐catenin cAct mice with a specific matrix metalloproteinase 13 inhibitor, ameliorated the mutant phenotype.ConclusionOur findings indicate that the β‐catenin signaling pathway plays a critical role in disc tissue function.
Life cycle assessment of biomethane from offshore‐cultivated seaweed
Authors: Langlois Juliette , Sassi Jean‐François , Jard Gwenaelle , Steyer Jean‐Philippe , Delgenes Jean‐Philippe , Hélias Arnaud 
Published: March 2012

AbstractAlgae are a promising source of industrial biomass for the future. In order to assess if aquacultured seaweed (macroalgae) could be considered an environmentally friendly source of biomass for bioenergy, life cycle assessments were performed for European countries, comparing methane as a biofuel from the anaerobic digestion (A) of whole seaweeds, (B) of alginate extraction residues, and (C) natural gas as a fossil fuel reference.These results clarify that the sources of electricity and energy used to heat the anaerobic digesters have an important impact. Recycling of materials and use of greenhouses at the nursery stage also allow environmental improvements for system (A). Ecodesign can make algal biomethane competitive in several categories compared to natural gas: a decrease of 21.9% and 54.2% in greenhouse gas (GHG) emissions and 58.6% and 68.7% in fossil depletion for systems (A) and (B), respectively, decrease in ozone depletion, and last but not least, improvement in the marine eutrophication index for system (A). For system (B), benefits are more arguable and dependent on the allocation. To conclude, seaweed could become competitive with terrestrial feedstock for biofuel production in the near future. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
Development and Testing of an Abbreviated Numeracy Scale: A Rasch Analysis Approach
Authors: Weller Joshua A. , Dieckmann Nathan F. , Tusler Martin , Mertz C. K. , Burns William J. , Peters Ellen 
Published: March 2012

ABSTRACTResearch has demonstrated that individual differences in numeracy may have important consequences for decision making. In the present paper, we develop a shorter, psychometrically improved measure of numeracy—the ability to understand, manipulate, and use numerical information, including probabilities. Across two large independent samples that varied widely in age and educational level, participants completed 18 items from existing numeracy measures. In Study 1, we conducted a Rasch analysis on the item pool and created an eight‐item numeracy scale that assesses a broader range of difficulty than previous scales. In Study 2, we replicated this eight‐item scale in a separate Rasch analysis using data from an independent sample. We also found that the new Rasch‐based numeracy scale, compared with previous measures, could predict decision‐making preferences obtained in past studies, supporting its predictive validity. In Study, 3, we further established the predictive validity of the Rasch‐based numeracy scale. Specifically, we examined the associations between numeracy and risk judgments, compared with previous scales. Overall, we found that the Rasch‐based scale was a better linear predictor of risk judgments than prior measures. Moreover, this study is the first to present the psychometric properties of several popular numeracy measures across a diverse sample of ages and educational level. We discuss the usefulness and the advantages of the new scale, which we feel can be used in a wide range of subject populations, allowing for a more clear understanding of how numeracy is associated with decision processes. Copyright © 2012 John Wiley & Sons, Ltd.
A protein‐stabilizing technology for enhanced antibody stability and antibody‐binding profiles in a microchip array
Authors: Scholz Martin , Lüking Angelika 
Published: March 2012

AbstractThe stability of therapeutic antibodies during downstream processing and storage is important for functionality and quality. To determine functional antibody performance, the UNIchip® high‐density protein microarray with 384 recombinant antigenic targets was developed; this allows characterization of antibody specificity by generating standardized quantitative binding profiles. In this study, we used UNIchip® to test the efficacy of a novel protein stabilizing and protecting solution (SPS) to preserve the binding specificity and binding strength of a therapeutic anti‐TNF‐α antibody (Adalimumab; Humira). Our results show that reconstituted SPS‐formulated and lyophilized Adalimumab elicits significantly less off‐target activity after reconstitution and preserves binding strength even after six weeks of storage at 40°C compared with Adalimumab that underwent the same treatment with the original formulation. By means of UNIchip®, we were able to confirm the protein stabilizing effects of SPS as shown by preserved antibody functionality.
Structured three‐dimensional co‐culture of mesenchymal stem cells with meniscus cells promotes meniscal phenotype without hypertrophy
Authors: Cui Xiaofeng , Hasegawa Akihiko , Lotz Martin , D'Lima Darryl 
Published: March 2012

AbstractMenisci play a crucial role in weight distribution, load bearing, shock absorption, lubrication, and nutrition of articular cartilage within the knee joint. Damage to the meniscus typically does not heal spontaneously due to its partial avascular nature. Partial or complete meniscectomy is a common clinical treatment of the defective meniscus. However, this procedure ultimately leads to osteoarthritis due to increased mechanical stress to the articular cartilage. Meniscus tissue engineering offers a promising solution for partial or complete meniscus deficiency. Mesenchymal stem cells (MSC) have the potential to differentiate into meniscal fibrochondrocyte as well as deliver trophic effects to the differentiated cells. This study tested the feasibility of using MSC co‐cultured with mature meniscal cells (MC) for meniscus tissue engineering. Structured cell pellets were created using MC and MSC at varying ratios (100:0, 75:25, 50:50, 25:75, and 0:100) and cultured with or without transforming growth factor‐beta 3 supplemented chondrogenic media for 21 days. The meniscal and hypertrophic gene expression, gross appearance and structure of the pellets, meniscus extracellular matrix (ECM), histology and immunohistochemistry of proteoglycan and collagen were evaluated. Co‐culture of MC with MSC at 75:25 demonstrated highest levels of collagen type I and glycosaminoglycans (GAG) production, as well as the lowest levels of hypertrophic genes, such as COL10A1 and MMP13. All co‐culture conditions showed better meniscus ECM production and hypertrophic inhibition as compared to MSC culture alone. The collagen fiber bundles observed in the co‐cultures are important to produce heterogenic ECM structure of meniscus. In conclusion, co‐culturing MC and MSC is a feasible and efficient approach to engineer meniscus tissue with enhanced ECM production without hypertrophy. Biotechnol. Bioeng. 2012;109: 2369–2380. © 2012 Wiley Periodicals, Inc.
Human mesenchymal stem cell position within scaffolds influences cell fate during dynamic culture
Authors: Yeatts Andrew B. , Geibel Elyse M. , Fears Fayola F. , Fisher John P. 
Published: March 2012

AbstractCell‐based tissue engineering is limited by the size of cell‐containing constructs that can be successfully cultured in vitro. This limit is largely a result of the slow diffusion of molecules such as oxygen into the interior of three‐dimensional scaffolds in static culture. Bioreactor culture has been shown to overcome these limits. In this study we utilize a tubular perfusion system (TPS) bioreactor for the three‐dimensional dynamic culture of human mesenchymal stem cells (hMSCs) in spherical alginate bead scaffolds. The goal of this study is to examine the effect of shear stress in the system and then quantify the proliferation and differentiation of hMSCs in different radial annuli of the scaffold. Shear stress was shown to have a temporal effect on hMSC osteoblastic differentiation with a strong correlation of shear stress, osteopontin, and bone morphogenic protein‐2 occurring on day 21, and weaker correlation occurring at early timepoints. Further results revealed an approximate 2.5‐fold increase in cell number in the inner annulus of TPS cultured constructs as compared to statically cultured constructs after 21 days. This result demonstrated a nutrient transfer limitation in static culture which can be mitigated by dynamic culture. A significant increase (P < 0.05) in mineralization in the inner and outer annuli of bioreactor cultured 4 mm scaffolds occurred on day 21 with 79 ± 29% and 53 ± 25% mineralization area, respectively, compared to 6 ± 4% and 19 ± 6% mineralization area, respectively, in inner and outer annuli of 4 mm statically cultured scaffolds. Surprising lower mineralization area was observed in 2 mm bioreactor cultured beads which had the highest levels of proliferation. These results may demonstrate a relationship between scaffold position and stem cell fate. In addition the decreased proliferation and matrix production in statically cultured scaffolds compared to bioreactor cultured constructs demonstrate the need for bioreactor systems and the effectiveness of the TPS bioreactor in promoting hMSC proliferation and differentiation in three‐dimensional scaffolds. Biotechnol. Bioeng. 2012;109: 2381–2391. © 2012 Wiley Periodicals, Inc.
Diffusion‐based extraction of DMSO from a cell suspension in a three stream, vertical microchannel
Authors: Hanna Jacob , Hubel Allison , Lemke Erin 
Published: March 2012

AbstractCells are routinely cryopreserved for investigative and therapeutic applications. The most common cryoprotective agent (CPA), dimethyl sulfoxide (DMSO), is toxic, and must be removed before cells can be used. This study uses a microfluidic device in which three streams flow vertically in parallel through a rectangular channel 500 µm in depth. Two wash streams flow on either side of a DMSO‐laden cell stream, allowing DMSO to diffuse into the wash and be removed, and the washed sample to be collected. The ability of the device to extract DMSO from a cell stream was investigated for sample flow rates from 0.5 to 4.0 mL/min (Pe = 1,263–10,100). Recovery of cells from the device was investigated using Jurkat cells (lymphoblasts) in suspensions ranging from 0.5% to 15% cells by volume. Cell recovery was >95% for all conditions investigated, while DMSO removal comparable to a previously developed two‐stream device was achieved in either one‐quarter the device length, or at four times the flow rate. The high cell recovery is a ∼25% improvement over standard cell washing techniques, and high flow rates achieved are uncommon among microfluidic devices, allowing for processing of clinically relevant cell populations. Biotechnol. Bioeng. 2012;109: 2316–2324. © 2012 Wiley Periodicals, Inc.
Rectal perforation with life-threatening peritonitis following stapled haemorrhoidopexy
Authors: Faucheron J-L , Voirin D , Abba J 
Published: March 2012

Abstract

Background
Stapled haemorrhoidopexy is a well recognized alternative to haemorrhoidectomy, and is associated with reduced pain and earlier return to normal activity. This paper reports all published cases of life-threatening sepsis following stapled haemorrhoidopexy, identifies causative factors and makes recommendations.

Methods
A systematic review of the literature was performed by searching the major electronic databases. All relevant references were reviewed for possible inclusion. All references of the relevant articles were screened for any further articles that were not identified in the initial search.

Results
From 2000 to the present, 29 articles reporting complications in 40 patients were identified. Thirty-five patients underwent laparotomy with faecal diversion and a further patient was treated by low anterior resection. A specific complication was rectal perforation with peritonitis. Factors that led to life-threatening sepsis were identified in 30 patients. Despite surgical treatment and resuscitation, there were four deaths.

Conclusion
Severe sepsis can complicate stapled haemorrhoidopexy. Rectal perforation and peritonitis are a particular risk of this technique and the associated mortality rate is high.