bluuebunny/crossref_metadata_2025_split huggingface dataset:
Myosin II is a negative regulator of oligodendrocyte morphological differentiation
Authors: Wang Haibo , Rusielewicz Tomasz , Tewari Ambika , Leitman Ellen M. , Einheber Steven , Melendez‐Vasquez Carmen V. 
Published: March 2012

AbstractDuring their development as myelinating cells, oligodendrocyte progenitors (OPC) undergo dramatic changes in the organization of their cytoskeleton. These changes involve an increase in cell branching and in lamella extension, which is important for the ability of oligodendrocytes to myelinate multiple axons in the CNS. We have previously shown that the levels of the actin‐associated motor protein nonmuscle myosin II (NMII) decrease as oligodendrocyte differentiate and that inhibition of NMII activity increases branching and myelination, suggesting that NMII is a negative regulator of oligodendrocyte differentiation. In agreement with this interpretation, we have found that overexpression of NMII prevents oligodendrocyte branching and differentiation and that OPC maturation is accelerated in NMII knockout mice as shown by a significant increase in the percentage of mature MBP+ cells. Although several pathways have been implicated in oligodendrocyte morphogenesis, their specific contribution to the regulation of NMII activity has not been directly examined. We tested the hypothesis that the activity of NMII in OPC is controlled by Fyn kinase via downregulation of RhoA‐ROCK‐NMII phosphorylation. We found that treatment with PP2 or knockdown of Fyn using siRNA prevents the decrease in myosin phosphorylation normally observed during OPC differentiation and that the inhibition of branching induced by overexpression of constitutively active RhoA can be reversed by treatment with Y27632 or blebbistatin. Taken together, our results demonstrate that Fyn kinase downregulates NMII activity, thus promoting oligodendrocyte morphological differentiation. © 2012 Wiley Periodicals, Inc.
The head‐mounted microscope
Authors: Chen Ting , Dailey Seth H. , Naze Sawyer A. , Jiang Jack J. 
Published: March 2012

AbstractMicrosurgical equipment has greatly advanced since the inception of the microscope into the operating room. These advancements have allowed for superior surgical precision and better post‐operative results. This study focuses on the use of the Leica HM500 head‐mounted microscope for the operating phonosurgeon. The head‐mounted microscope has an optical zoom from 2× to 9× and provides a working distance from 300mm to 700mm. The headpiece, with its articulated eyepieces, adjusts easily to head shape and circumference, and offers a focus function, which is either automatic or manually controlled. We performed five microlaryngoscopic operations utilizing the head‐mounted microscope with successful results. By creating a more ergonomically favorable operating posture, a surgeon may be able to obtain greater precision and success in phonomicrosurgery. Phonomicrosurgery requires the precise manipulation of long‐handled cantilevered instruments through the narrow bore of a laryngoscope. The head‐mounted microscope shortens the working distance compared with a stand microscope, thereby increasing arm stability, which may improve surgical precision. Also, the head‐mounted design permits flexibility in head position, enabling operator comfort, and delaying musculoskeletal fatigue. A head‐mounted microscope decreases the working distance and provides better ergonomics in laryngoscopic microsurgery. These advances provide the potential to promote precision in phonomicrosurgery. Laryngoscope, 2012
Paradoxical vocal cord motion: Classification and treatment
Authors: Forrest L. Arick , Husein Tiffany , Husein Omar 
Published: March 2012

AbstractParadoxical vocal cord motion (PVCM), or vocal cord dysfunction, is a descriptive term for inappropriate adduction of the vocal folds during respiration. The laryngeal mistiming leads to breathing difficulty and is often misdiagnosed as refractory asthma. The etiology of PVCM has been unclear but has long been hypothesized to be psychological. The present thesis is a prospective study of 170 patients older than 18 years being evaluated for PVCM, with 117 of the 170 (68.8%) identified as having PVCM by video laryngoscopy. Laryngeal edema (P = .021) and reflux (P = .026) were increased in patients with PVCM. A flat inspiratory arm of the flow volume loop during spirometry testing was a predictor of PVCM (P = .034). A subgroup of 47 newly diagnosed patients with PVCM underwent psychological analysis. The psychological profiles were elucidated using the Minnesota Multiphasic Personality Inventory and the Life Experiences Survey to evaluate stress. Compared to established normative data, PVCM demonstrated a conversion disorder pattern (P < .01) but not an anxiety disorder or a correlation with stress. A subgroup, 11 of the 47 (23.4%), had normal psychological outcomes, and two of the 47 (4.3%) were identified as malingering. Previous studies have suggested that PVCM is strictly a psychological disorder. It is proposed that PVCM is a descriptive term that is multifactorial and the etiology should direct treatment. A classification scheme divides PVCM into primary, or psychological, and secondary. The secondary form consists of medical disorders divided into irritable larynx syndrome and neurologic disorders. Laryngoscope, 2012
Vinyl‐Type Polynorbornenes with Pendant PCBM: A Novel Acceptor for Organic Solar Cells
Authors: Eo Maengsun , Lee Soohyun , Park Myung Hwan , Lee Min Hyung , Yoo Seunghyup , Do Youngkyu 
Published: March 2012

AbstractVinyl addition homo‐ and copolymerization of norbornene monomer (M1) functionalized with a PCBM moiety using a Pd(II) catalyst in combination with a 1‐octene chain transfer agent efficiently produces polynorbornenes with side‐chain PCBM groups. Characterization by NMR spectroscopy and elemental analysis reveals that the copolymers constitute a well‐defined polymer structure with controlled incorporation of M1. Although the homopolymer is insoluble in organic solvents, the copolymers containing 62 mol% (P2) and 50 mol% (P3) of the PCBM moiety are soluble in chlorinated solvents such as o‐dichlorobenzene. The bulk‐heterojunction organic photovoltaic devices fabricated based on the P3HT:P3 blends show that P3 can adequately function as an electron acceptor, leading to a cell with a power conversion efficiency of 1.5%, which is outstanding among the polymeric rivals.
Total scalp reconstruction with bilateral anterolateral thigh flaps
Authors: Kwee Melissa M. , Rozen Warren M. , Ting Jeannette W.C. , Mirkazemi Mansoor , Leong James , Baillieu Charles 
Published: March 2012

AbstractLarge scalp defects can require complicated options for reconstruction, often only achieved with free flaps. In some cases, even a single free flap may not suffice. We review the literature for options in the coverage of all reported large scalp defects, and report a unique case in which total scalp reconstruction was required. In this case, two anterolateral thigh (ALT) flaps were used to resurface a large scalp and defect, covering a total of 743 cm2. The defect occurred after resection and radiotherapy for desmoplastic melanoma, with several failed skin grafts and local flaps and osteoradionecrosis involving both inner and outer tables of the skull. The reconstruction was achieved as a single‐stage reconstruction and involved wide resection of cranium and overlying soft‐tissues and reconstruction with calcium phosphate bone graft substitute, titanium mesh, and two large ALT flaps. The reconstruction was successfully achieved, with minor postoperative complications including tip necrosis of one of the flaps and wound breakdown at one of the donor sites. This is the first reported case of two large ALT flaps for scalp resurfacing and may be the largest reported scalp defect to be completely resurfaced by free flaps. The useof bilateral ALT flaps can be a viable option for the reconstruction of large and/or complicated scalp defects. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012.
Fibulo‐scapho‐lunate arthrodesis after resection of the distal radius for giant‐cell tumor of the bone
Authors: Jaminet Patrick , Rahmanian‐Schwarz Afshin , Pfau Mathias , Nusche Andreas , Schaller Hans‐Eberhard , Lotter Oliver 
Published: March 2012

AbstractBackground:Giant‐cell tumors of the distal radius are rare. They have a high‐risk of local recurrence and a risk of pulmonary metastasis. Curettage alone or combined with adjunctive agents is often associated with local recurrence.Methods:Three patients with giant‐cell tumor of the distal radius are presented. All patients showed Campanacci grade 3 lesions. All patients underwent complete distal radius resection and reconstruction with a vascularized fibular graft distally fused with the scaphoid and the lunate, allowing midcarpal motion.Results:The follow‐up period ranged from 6 to 60 months. For all three patients, emotional acceptance was excellent. The postoperative motion of the wrist was good, with a range of motion of 30‐0‐30°, 40‐0‐0°, and 30‐0‐10° (extension–flexion). There was neither tumor recurrence nor pulmonary metastasis.Conclusion:Fibulo‐scapho‐lunate fusion is an elegant method of distal radius reconstruction with good functional outcome and low risk of pulmonary metastasis. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012.
Patch‐averaged assumed strain finite elements for stress analysis
Authors: Castellazzi G. , Krysl P. 
Published: March 2012

SUMMARYA finite element model for linear‐elastic small deformation problems is presented. The formulation is based on a weighted residual that requires a priori the satisfaction of the kinematic equation. In this approach, an averaged strain‐displacement matrix is constructed for each node of the mesh by defining an appropriate patch of elements, yielding a smooth representation of strain and stress fields. Connections with traditional and similar procedure are explored. Linear quadrilateral four‐node and linear hexahedral eight‐node elements are derived. Various numerical tests show the accuracy and convergence properties of the proposed elements in comparison with extant finite elements and analytic solutions. Specific examples are also included to illustrate the ability to resist numerical locking in the incompressible limit and insensitive response in the presence of shape distortion. Furthermore, the numerical inf‐sup test is applied to a selection of problems to show the stability of the present formulation. Copyright © 2012 John Wiley & Sons, Ltd.
Extruded foams from microbial poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) and its blends with cellulose acetate butyrate
Authors: Liao Qi , Tsui Amy , Billington Sarah , Frank Curtis W. 
Published: March 2012

AbstractExtrusion foaming of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) and two blends of PHBV with cellulose acetate butyrate (CAB) were studied using an azodicarbonamide (AZ) blowing agent and a single‐screw extruder. The concentration of the blowing agent was systematically varied from 0 to 4.0 phr to achieve maximum density reduction reaching 41%, as well as to obtain information on the dependence of cell growth on blowing agent concentration. Extruded foams were characterized in terms of their bulk densities and cellular morphologies. Stereological and statistical methods permitted full characterization of the three‐dimensional cell size distributions, assessing the average cell diameters (ranging from 58 to 290 μm) and cell densities (ranging from 650 to 180,000 cm−3). The variation in cellular morphology among foams consisting of different polymer matrix or blowing agent concentration was compared. The results were analyzed by considering the influence of viscoelastic properties of the polymer matrix on the bubble growth during foaming. Significantly higher melt viscosity and elasticity and reduced gas solubility of the PHBV/CAB blends are believed to retard cell coalescence and collapse during foam expansion, resulting in more uniform cell size distribution and better homogeneity of cellular morphology. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Real‐time crystalline orientation measurements during low‐density polyethylene blown film extrusion using wide‐angle X‐ray diffraction
Authors: Gururajan Giriprasath , Ogale Amod A. 
Published: March 2012

AbstractReal‐time wide‐angle X‐ray diffraction studies were successfully used to investigate the effect of film blowing process parameter on the crystalline orientation development during the blown film extrusion of low‐density polyethylene. Azimuthal distribution scans showed the evolution of crystalline orientation in the bubble from an isotropic state to an oriented state as inferred from (110) and (200) planes. These real‐time X‐ray diffraction measurements in a blown film line are consistent with prior observations using polarized Raman spectroscopy (Gururajan and Ogale, J. Raman Spectrosc.,
40, 212 (2009)) and small‐angle light scattering (Bullwinkel et al., Int. Polym. Proc., 16, 41 (2001)) that significant molecular orientation takes place past the frost‐line height, even after the blown film diameter is locked into place. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Characterization of the viscoelastic properties of poly(ε‐caprolactone)–hydroxyapatite microcomposite and nanocomposite scaffolds
Authors: Leung Linus H. , Naguib Hani E. 
Published: March 2012

AbstractIn bone tissue engineering, the mechanical properties of the scaffolds need to be sufficiently high to prevent material failure when bearing loads. To strengthen the scaffold, various composites have been proposed in the literature, including poly(ε‐caprolactone) with hydroxyapatite (HA). In this study, the processing of this composite using the gas foaming/salt leaching technique is examined. The control of scaffold properties by varying the processing parameters was first investigated. Then, the change in properties, with a focus on the viscoelastic properties, from the varying morphology was examined. Although an increase in scaffold density and pore size increased the scaffold modulus, it did not significantly affect the viscoelastic properties. Furthermore, the addition of HA decreased the scaffold modulus and increased the loss factor of the composite scaffolds. The more viscoelastic behavior is believed to be due to the more open structure that was created. When tested in a water bath to better simulate the physiological environment, the mechanical properties decreased by up to 85%, and the scaffolds also behaved more viscoelastically. The comparison of the scaffold properties shows the differing behavior of the scaffolds in dry and wet conditions. Hence, the environment of testing should be more carefully considered when designing experiments. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Effect of benzyl triethylammonium chloride on microstructure of bicomponent polymeric fibers during electrospinning
Authors: Lu Weili , Liu Xiwang , Zhao Shengling , Na Haining , Zhao Yunhui , Yuan Xiaoyan 
Published: March 2012

AbstractEffect of benzyl triethylammonium chloride (BTEAC) on the microstructure of electrospun bicomponent fibers, i.e., polyvinylidene fluoride (PVDF)/polycarbonate (PC), polyacrylonitrile (PAN)/polyethylene glycol (PEG), and PAN/PVDF, was investigated in this article. The evolution of morphology and microstructure of the above bicomponent fibers were examined by scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectroscopy. The results showed that distinct core/shell structured fibers were successfully prepared from PVDF/PC and PAN/PVDF via introducing a small amount of BTEAC, whereas only cocontinuous structure was detected in the electrospun PAN/PEG fibers. This study could be an example of electrospun multipolymer dispersions influencing by an organic salt, and it could be extended to control the structure of carbon nanofibers via electrospinning. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Facile preparation of water‐dispersible graphene nanosheets by covalent functionalization with poly(3‐aminobenzene sulfonic acid)
Authors: Pham Tuan Anh , Kim Jong Su , Kim Don , Jeong Yeon Tae 
Published: March 2012

AbstractThe synthesis of water‐dispersilbe graphene nanosheets plays an important role in various practical applications. Herein, we have demonstrated an efficient method for the preparation of water‐dispersible graphene hybrid material from graphene oxide (GO) and a hydrophilic‐conducting polymer, namely, poly(3‐aminobenzene sulfonic acid) (PABS). First, the covalent functionalization process of GO with PABS was carried out via a simple amidation reaction between acyl chloride group located on GO surface and the amino group present in the polymer. Second, the GO‐polymer hybrid was chemically reduced into graphene‐polymer hybrid using sodium borohydride as a reducing agent. The resulting hybrid material was characterized using various analytical techniques. Electron microscopic studies were used to characterize the morphology and chemical structure of the resulting hybrids. Fourier transform infrared spectroscopy was used to investigate the initial changes in surface functionalities, while the thermal stability of hybrid material on heating was studied via thermogravimetric analysis. The digital images provided a vivid observation on the high‐dispersion stability of the hybrid material in distilled water. POLYM. ENG. SCI., 52:1854–1861, 2012. © 2012 Society of Plastics Engineers
Thermal, mechanical, and barrier properties of polyethylene terephthalate‐platelet nanocomposites prepared by in situ polymerization
Authors: Li Shigeng , Auddy Kausick , Barber Peter , Hansen Tara J. , Ma Jisheng , zur Loye Hans‐Conrad , Ploehn Harry J. 
Published: March 2012

AbstractThis study used in situ polymerization to prepare polyethylene terephthalate (PET) nanocomposites incorporating Ethoquad‐modified montmorillonite (eMMT), unmodified hectorite (HCT), or phenyl hectorite (phHCT) particles to study the impact of platelet surface chemistry and loading on thermal, mechanical, and gas barrier properties. eMMT platelets reduced the PET crystallization rate without altering the ultimate degree of crystallinity. In contrast, HCT and phHCT platelets accelerated the polymer's crystallization rate and increased its crystallinity. DMA results for thermally‐quenched samples showed that as T increased past glass transition temperature (Tg), HCT and phHCT nanocomposites (and control PET) manifested precipitous drops in G′ followed by increasing G′ due to cold crystallization; in contrast, eMMT nanocomposites had much higher G′ values around Tg. This provides direct evidence of eMMT reinforcement in thermally‐quenched eMMT nanocomposites. These results suggest that eMMT has a strong, favorable interaction with PET, possibly through Ethoquad‐PET entanglement. HCT and phHCT have a fundamentally different interaction with PET that increases crystallization rate and Tg by 11 to 17°C. Water barrier improvement in eMMT nanocomposites agrees with previously published oxygen barrier results and can be rationalized in terms of a tortuous path gas barrier model. POLYM. ENG. SCI., 52:1888–1902, 2012. © 2012 Society of Plastics Engineers
Surface modifications of polypropylene with nonylphenol ethoxylates melt additives
Authors: Datla V. , Shim E. , Pourdeyhimi B. 
Published: March 2012

AbstractNonylphenol ethoxylated (NPE) additives were melt blended in polypropylene (PP) films and characteristics of the modified films were investigated. It was found that melt blending of NPE additives improved hydrophilicity of PP films through additive surface segregation. Surface specific techniques, such as X‐ray photoelectron spectroscopy (XPS) and Time‐of‐Flight Secondary Ion Mass Spectrometry (ToF‐SIMS) were used to study surface compositions of samples modified with NPE additives at different aging time after extrusion. We found that surface enrichment of additives lead to hydrophilic surfaces. Hydrophilic chain length in NPE affected surface composition and hydrophilicity of NPE containing PP polymer. The effect of water immersion and aging were also reported. POLYM. ENG. SCI., 52:1920–1927, 2012. © 2012 Society of Plastics Engineers
The protein gp74 from the bacteriophage HK97 functions as a HNH endonuclease
Authors: Moodley Serisha , Maxwell Karen L. , Kanelis Voula 
Published: March 2012

AbstractThe last gene in the genome of the bacteriophage HK97 encodes the protein gp74. We present data in this article that demonstrates, for the first time, that gp74 possesses HNH endonuclease activity. HNH endonucleases are small DNA binding and digestion proteins characterized by two His residues and an Asn residue. We demonstrate that gp74 cleaves lambda phage DNA at multiple sites and that gp74 requires divalent metals for its endonuclease activity. We also present intrinsic tryptophan fluorescence data that show direct binding of Ni2+ to gp74. The activity of gp74 in the presence of Ni2+ is significantly decreased below neutral pH, suggesting the presence of one or more His residues in metal binding and/or DNA digestion. Surprisingly, this pH‐dependence of activity is not seen with Zn2+, suggesting a different mode of binding of Zn2+ and Ni2+. This difference in activity may result from binding of a second Zn2+ ion by a putative zinc finger in gp74 in addition to binding of a Zn2+ ion by the HNH motif. These studies define the biochemical function of gp74 as an HNH endonuclease and provide a platform for determining the role of gp74 in life cycle of the bacteriophage HK97.
Manufacture and characterisation of thin flat and curved auxetic foam sheets
Authors: Alderson Kim , Alderson Andrew , Ravirala Naveen , Simkins Virginia , Davies Philip 
Published: March 2012

AbstractA new method for the production of thin flat and curved auxetic foam sheets by uniaxial compression is reportted in this paper. Detailed optical microscopy and Poisson's ratio measurement by videoextensometry has revealed that the auxetic behaviour is due to a crumpling of the pores through the foam thickness, caused by a uniaxial compression of 40–60% in combination with shear for the curved foams. Poisson's ratio values of up to −3 have been recorded for the curved foams and −0.3 for the flat sheets.
Adaptive Coding and Modulation‐enabled satellite triple play over DVB‐S2 (Digital Video Broadcasting ‐ Satellite ‐ Second Generation): a techno‐economic study
Authors: Anastasiadou N. , Gardikis G. , Nikiforiadis A. , Pangalos S. 
Published: March 2012

SUMMARYThis article looks at the techno‐economic perspectives of the use of DVB‐S2 (Digital Video Broadcasting ‐ Satellite ‐ Second Generation) and its unique feature, Adaptive Coding and Modulation (ACM) in the provision of satellite triple play. For this study, current market economic data were used, in conjunction with technical results derived within the European Union‐funded IST IMOSAN project. IMOSAN (Integrated Multi‐Layer Optimisation in DVB‐S2 Satellite Networks) succeeded in realising the provision of satellite triple play over an interactive DVB‐S2/DVB‐RCS (Return Channel via Satellite) platform. The ACM feature of DVB‐S2 was exploited, yielding increased spectrum efficiency and thus decreasing service cost. One‐user‐per‐terminal scenarios are examined, as well as terrestrial redistribution of satellite services to a group of users via WiMAX. Copyright © 2012 John Wiley & Sons, Ltd.