bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural characteristics of spermatogenesis in Pallas's mastiff bat, Molossus molossus (Chiroptera: Molossidae)
Authors: Beguelini Mateus R. , Taboga Sebastião R. , Morielle‐Versute Eliana 
Published: January 2012

AbstractDespite the large number of species, their wide distribution, and unique reproductive characteristics, Neotropical bats have been poorly studied, and important aspects of the reproduction of these animals have not been elucidated. We made an ultrastructural analysis of spermatogenesis in Molossus molossus (Molossidae). The process of spermatogonial differentiation is similar to that found in other bats and is also relatively similar to that of Primates, with three main spermatogonia types: Ad, Ap, and B. Meiotic divisions proceed similarly to those of most mammals, and spermiogenesis is clearly divided into 12 steps, in the middle of the range known for bats (9–16 steps). Formation of the acrosome is similar to that known from other mammals; however, the ultrastructure of spermatozoa was found to have unique characteristics, including many wavy acrosomal projections on its surface, which seems to be specific for the family Molossidae. Comparing the ultrastructure of the spermatozoon of M. molossus with other bats already study, we observed that three characters vary: morphology of the outer dense fibers, of the perforatorium, and of the spermatozoon head. The great similarity of morphological characters between M. molossus and Platyrrhinus lineatus suggests that M. molossus is more closely related to the Phyllostomidae than to the Rhinolophidae and the Vespertilionidae. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.
Motor performance of young dystrophic mdx mice treated with long‐circulating prednisolone liposomes
Authors: Weller Charlotte , Zschüntzsch Jana , Makosch Gregor , Metselaar Josbert M. , Klinker Florian , Klinge Lars , Liebetanz David , Schmidt Jens 
Published: January 2012

AbstractFor Duchenne muscular dystrophy (DMD), a common myopathy that leads to severe disability, no causal therapy is available. Glucocorticosteroids improve patients' muscle strength, but their long‐term use is limited by negative side effects. Thus, pharmacological modifications of glucocorticosteroids are required to increase the efficacy by drug targeting. Liposomal encapsulation augments systemic half‐life and local tissue concentrations of glucocorticosteroids and, at the same time, reduces systemic side effects. In this study, the efficacy of novel, long‐circulating, polyethylene‐glycol‐coated liposomes encapsulating prednisolone was compared with free prednisolone in the treatment of mdx mice, a well‐established animal model for DMD. Using an objective and sensitive computerized 24‐hr detection system of voluntary wheel‐running in single cages, we demonstrate a significant impairment of the running performance in mdx compared with black/10 control mice aged 3–6 weeks. Treatment with liposomal or free prednisolone did not improve running performance compared with saline control or empty liposomes. Histopathological parameters, including the rate of internalized nuclei and fiber size variation, and mRNA and protein expression levels of transforming growth factor (TGF)‐β and monocytes chemotactic protein (MCP)‐1 also remained unchanged. Bioactivity in skeletal muscle of liposomal and free prednisolone was demonstrated by elevated mRNA expression of muscle ring finger protein 1 (MuRF1), a mediator of muscle atrophy, and its forkhead box transcription factors (Foxo1/3). Our data support the assessment of voluntary running to be a robust and reproducible outcome measure of skeletal muscle performance during the early disease course of mdx mice and suggest that liposomal encapsulation is not superior in treatment efficacy compared with conventional prednisolone. Our study helps to improve the future design of experimental treatment in animal models of neuromuscular diseases. © 2012 Wiley Periodicals, Inc.
ID2: A negative transcription factor regulating oligodendroglia differentiation
Authors: Chen Xing‐Shu , Zhang Yu‐Hang , Cai Qi‐Yan , Yao Zhong‐Xiang 
Published: January 2012

AbstractRemyelination of the central nervous system in multiple sclerosis patients is often incomplete. Remyelination depends on normal oligodendrogenesis and the differentiation of oligodendrocyte precursor cells (OPC) into mature oligodendrocytes (OL). Inhibitor of DNA binding (ID), a transcription factor, is thought to inhibit oligodendrogenesis and the differentiation of OPC. This Mini‐Review aims to reveal the roles of and mechanisms used by IDs (mainly ID2) in this process. An interaction between ID2 and retinoblastoma tumor suppressor is responsible for the cell cycle transition from G1 to S. The translocation of ID2 between the nucleus and cytoplasm is regulated by E47 and OLIG. An interaction between ID2 and OLIG mediates the inhibitory effects of bone morphogenic proteins and G protein‐coupled receptor 17 on oligodendroglia differentiation. ID2 expression is regulated by Wnt and histone deacetylases during the differentiation of OPC. ID4, another member of the ID family, functions similarly to ID2 in regulating the differentiation of OPC. The main difference is that ID4 is essential for oligodendrogenesis, whereas ID2 is nonessential. This could have important implications for demyelinating diseases, and interfering with these pathways might represent a viable therapeutic approach for these diseases. © 2012 Wiley Periodicals, Inc.
Altered microtubule dynamics in Mecp2‐deficient astrocytes
Authors: Nectoux Juliette , Florian Cedrick , Delepine Chloe , Bahi‐Buisson Nadia , Khelfaoui Malik , Reibel Sophie , Chelly Jamel , Bienvenu Thierry 
Published: January 2012

AbstractRett syndrome (RTT) is a severe neurodevelopmental disorder caused by mutations in the gene MECP2 encoding the methyl‐CpG binding protein 2. This genetic disease affects predominantly girls and is characterized by a period of normal development that lasts for 8–18 months, followed by neurologic regression affecting both motor and mental abilities. Previous studies performed on brains from RTT subjects and Mecp2‐deficient mice showed striking changes in neuronal maturation and dendritic arborization. Recently, we showed that expression of stathmin‐like 2 (STMN2) was significantly reduced in fibroblasts from RTT patients, and similar results were obtained in the cerebellum of Mecp2‐deficient mice. Because assembly and dynamics of microtubules are known to be modulated by STMN2, we studied microtubule dynamics in brain cells from Mecp2‐deficient mice. We observed that Mecp2 deficiency affects microtubule dynamics in astrocytes from Mecp2‐deficient mice. Our data reinforce the fact that the loss of Mecp2 in astrocytes may influence the onset and progression of RTT. These results imply that Mecp2 has a stabilizing role in microtubule dynamics and that Mecp2 deficiency, which is associated with STMN2 down‐regulation, could lead to impaired microtubule stability, hence explaining the dendritic abnormalities observed in RTT brains. © 2012 Wiley Periodicals, Inc.
Herpes simplex virus type 1 induces nuclear accumulation of hyperphosphorylated tau in neuronal cells
Authors: Álvarez Gema , Aldudo Jesús , Alonso María , Santana Soraya , Valdivieso Fernando 
Published: January 2012

AbstractHerpes simplex virus type 1 (HSV‐1) is a neurotropic virus that remains latent in host neurons. Viral DNA replication is a highly structured process in which the redistribution of nuclear proteins plays an important role. Although tau is most widely known as a microtubule‐associated protein found in a hyperphosphorylated state in the brains of patients with Alzheimer's disease (AD), this protein has also been detected at other sites such as the nucleolus. Here, we establish that HSV‐1 infection gives rise to an increase in tau phosphorylation and that hyperphosphorylated tau accumulates in the nucleus, forming defined structures in HSV‐1‐infected neuronal cells reminiscent of the common sites of viral DNA replication. When tau expression in human neuroblastoma cells was specifically inhibited using an adenoviral vector expressing a short hairpin RNA to tau, viral DNA replication was not affected, indicating that tau is not required for HSV‐1 growth in neuronal cells. Given that HSV‐1 is considered a risk factor for AD, our results suggest a new way in which to understand the relationships between HSV‐1 infection and the pathogenic mechanisms leading to AD. © 2012 Wiley Periodicals, Inc.
Implementation teams: A new lever for organizational change
Authors: Higgins Monica C. , Weiner Jennie , Young Lissa 
Published: January 2012

SummaryThis paper introduces a team form called an “implementation team”—a team charged with designing and leading the implementation of an organization‐wide change strategy—and investigates this team type in a context ripe for change, U.S. public school systems. Unlike prior teams research that has focused on teams as diagnostic collectives or strategic decision‐making bodies, this study forwards the notion that teams can be used to implement organizational change. In this study, we examined how positional and tenure diversity and work context relate to team member learning, a critical factor in sustaining organizational change. Results from 25 school district instructional improvement strategy teams over two years challenge some basic assumptions regarding what constitutes a “real team.” We find that some taken‐for‐granted aspects of teams, such as team member stability, may not be central or even appropriate when considering “real teams” in this change context; rather than stability of team membership, the stability of members' roles may matter most. We conclude by suggesting that scholars further investigate this team form and reframe, reconsider, and renew their conceptualizations of “real teams,” especially for teams engaged in implementing organizational change. Copyright © 2012 John Wiley & Sons, Ltd.
Sociometric badges: Using sensor technology to capture new forms of collaboration
Authors: Kim Taemie , McFee Erin , Olguin Daniel Olguin , Waber Ben , Pentland Alex “Sandy” 
Published: January 2012

SummaryThis article introduces sociometric badges as a research tool that captures with great accuracy fine‐scale speech patterns and body movements among a group of individuals at a scale that heretofore has been impossible in groups and teams studies. Such a tool offers great potential for studying the changing ecology of team structures and new modes of collaboration. Team boundaries are blurring as members disperse across multiple cultures, convene through various media, and operate in new configurations. As the how and why of collaboration evolves, an opportunity emerges to reassess the methods used to capture these interactions and to identify new tools that might help us create synergies across existing approaches to teams research. We offer sociometric badges as a complement to existing data collection methods—one that is well‐positioned to capture real‐time collaboration in new forms of teams. Used as one component in a multi‐method approach, sociometric badges can capture what an observer or cross‐sectional survey might miss, contributing to a more accurate understanding of group dynamics in new teams. We also revisit traditional teams research to suggest how we might use these badges to tackle long‐standing challenges. We conclude with three case studies demonstrating potential applications of these sociometric badges. Copyright © 2012 John Wiley & Sons, Ltd.
Endonasal endoscopic exposure of the internal carotid artery: An anatomical study
Authors: Fortes Felipe S. G. , Pinheiro‐Neto Carlos D. , Carrau Ricardo L. , Brito Rubens V. , Prevedello Daniel M. , Sennes Luiz U. 
Published: January 2012

AbstractObjectives/Hypothesis:The aim of this work was to define the anatomical landmarks, limitations, and difficulties of obtaining internal carotid artery (ICA) exposure via endonasal endoscopic approaches (EEA).Study Design:Cadaveric descriptive study.Methods:The ICA was dissected via EEA in 10 cadaveric specimens (20 sides) prepared with intravascular injections of colored silicone. We carried the ICA dissection from the cavernous to the distal parapharyngeal segments through a transpterygoid corridor.Results:The transpterygoid approach provided adequate exposure of the lacerum and horizontal petrous ICA. Additional exposure of the ICA and the infrapetrous area required resection of the eustachian tube (ET) and the fibrocartilaginous tissue of the foramen lacerum after a medial maxillectomy and resection of the pterygoid plates. The main anatomical landmarks to the corresponding ICA segment include: the vidian nerve that points to the lacerum and horizontal segments, the mandibular nerve (V3) that heralds the petrous segment, the foramen ovale and the ET that signal toward the carotid canal, and the posterior trunk of the mandibular nerve (V3) and the ET that mark the parapharyngeal segment.Conclusions:EEAs provide access to the ICA from its cavernous to the distal parapharyngeal segments. A stepwise approach is critical to its exposure and control. Surgeons must be aware of its frequently tortuous three‐dimensional course and the intimate relation of the vessel to the carotid canal and the cartilage of the foramen lacerum.
Current dysphonia trends in patients over the age of 65: Is vocal atrophy becoming more prevalent?
Authors: Davids Taryn , Klein Adam M. , Johns Michael M. 
Published: January 2012

AbstractObjectives/Hypothesis:The current trends in geriatric voice referrals including the number of patients over the age of 65 years seen per year, the common diagnostic patterns, and specifically the number of patients with vocal atrophy were assessed.Study Design:Retrospective cohort study.Methods:A retrospective chart review of all patients seen at the Emory Voice Center for otolaryngologic complaints between the years of 2004 and 2009 was performed.Results:Of the 6,360 patients seen over a 6‐year period, 21% were over the age of 65 years. Fifty‐eight percent of patients over the age of 65 years had vocal complaints, with the most common diagnoses being vocal atrophy (25%), neurologic vocal dysfunction (23%), and vocal fold immobility (19.2%). Of those patients diagnosed with vocal atrophy, the majority opted for voice therapy (57%), followed by reassurance (39%), and injection laryngoplasty (6%). There was a statistically significant improvement in mean pretherapy and post‐therapy voice‐related quality of life (VRQOL) score.Conclusions:As the number of people in the over 65‐year‐old age bracket increases, so do the number of geriatric referrals. Although diagnostic trends remain the same, vocal atrophy is becoming more prevalent, with a large number of patients seeking intervention. This will likely result in an increased need for health resources in the future.
Sharps exposures among otolaryngology–head and neck surgery residents
Authors: Vanhille Derek L. , Maiberger Patrick G. , Peng Angela , Reiter Evan R. 
Published: January 2012

AbstractObjectives/Hypothesis:Examine the incidence of sharps exposures among otolaryngology residents, assess characteristics of exposures, and determine rates of reporting these potentially career‐ and life‐impacting exposures.Study Design:Cohort study of otolaryngology–head and neck surgery residents.Methods:Survey was administered online to otolaryngology residents in the spring of 2008, gathering demographic information, characteristics of sharps exposures, and residents' self‐reporting of sharps exposures.Results:Among 1,407 otolaryngology residents nationwide, 231 completed the survey. Of these, 168 (72.7%) had at least one sharps exposure during residency, with most due to solid‐bore needles (51.7%) and occurring in the operating room (67%). Fifty percent of residents reported exposures occurring in postgraduate year (PGY)‐3 or PGY‐4, whereas exposures occurred at slightly lower rates in the other PGYs. There was no difference in incidence of sharps exposures based on gender (Fisher exact test, P = .2742) or history of sharps exposure during medical school (Fisher exact test, P = .7559). Seventy‐four participants had an exposure that they did not report to the hospital, with the most common reason for not reporting being the perceived burden of the hospital testing protocol.Conclusions:Otolaryngology residents report a high rate of sharps exposures during residency training, with a significant number of these exposures going unreported. Better education may be needed to help decrease these often preventable workplace exposures and to improve compliance with reporting and testing procedures.
Positivity properties for the clamped plate boundary problem on the ellipse and strip
Authors: Render Hermann , Ghergu Marius 
Published: January 2012

AbstractThe positivity preserving property for the biharmonic operator with Dirichlet boundary condition is investigated. We discuss here the case where the domain is an ellipse (that may degenerate to a strip) and the data is a polynomial function. We provide various conditions for which the positivity is preserved.
Fabrication of Chitosan Single‐Component Microcapsules With a Micrometer‐Thick and Layered Wall Structure by Stepwise Core‐Mediated Precipitation
Authors: Han Yuanyuan , Tong Weijun , Zhang Yuying , Gao Changyou 
Published: January 2012

AbstractIncubation of CaCO3 microparticles in chitosan (CS) solution at pH 5.2 and following with ethylenediaminetetraacetic acid disodium salt (EDTA) treatment resulted in CS single‐component microcapsules with an ultra‐thick wall structure. Repeating the incubation caused stepwise increase of wall thickness and finally resulted in CS microcapsules with a layered structure. This unique method is mediated by precipitation of CS on the CaCO3 particles as a result of pH increase caused by the partial dissolution of CaCO3. The obtained CS capsules are stable at neutral pH.
Novel Source of Trifluoromethyl Radical As Efficient Initiator for the Polymerization of Vinylidene Fluoride
Authors: Boschet Frédéric , Ono Taizo , Ameduri Bruno 
Published: January 2012

AbstractA persistent perfluoroalkyl radical (PPFR), perfluoro‐3‐ethyl‐2,4‐dimethyl‐3‐pentyl, is shown to be a good source of •CF3 radicals and a useful radical capable of initiating the polymerization of vinylidene fluoride (VDF). NMR characterizations of the resulting PVDF homopolymers showed that polymerization of VDF was exclusively initiated by •CF3 radicals. The addition of •CF3 radical onto VDF was regioselective leading to CF3‐CH2‐CF2‐PVDF and the CF3 end‐group acted as an efficient label to assess the molecular weights by 19F NMR spectroscopy. Various [PPFR]0/[VDF]0 initial molar ratios lead to CF3–PVDF–CF3 of different molecular weights. When that ratio decreased, both the molecular weights and the thermostability of these PVDFs increased, showing less defects of chaining and higher crystallinity.
Distortion engineering – interim results after one decade research within the Collaborative Research Center
Authors: Zoch H.‐W. 
Published: January 2012

AbstractThe result of distortion during manufacturing and its removal or correction totally amounts to similar economical losses in industry as known by wear or corrosion phenomena. Therefore over a long time high efforts have been taken to avoid or minimize distortion, starting with basic investigations at the beginning of the last century. The increasing importance led to intensified research, culminating in the late 90's with several investigations on steel grades and productions routes and their impact on dimensional changes. Focussing on separated aspects and influencing parameters before, the establishment of the Collaborative Research Center “Distortion Engineering” at Bremen University, funded by the Deutsche Forschungsgemeinschaft (DFG), first time treated distortion as a system attribute and result of the entire process chain. After 11 years of project work in the CRC, which ends in 2011, a summary of achievements and outlook on further investigations is given.
Distortion of rings due to inhomogeneous temperature distribution
Authors: Surm H. , Frerichs F. , Lübben T. , Hoffmann F. , Zoch H.‐W. 
Published: January 2012

AbstractIn this paper, experimental results regarding the effect of asymmetric temperature distributions on shape changes of different ring types due to heat treatment will be presented. The main part of the distortion can be attributed to a distortion mechanism which is caused by the interaction of an inhomogeneous temperature distribution and the corresponding local phase transformation: In particular plastic strains by transformation plasticity dominate the change in roundness and the change of the angle of the raceways. To evaluate the portion on roundness deviation which can be attributed to sole thermal stress and/or transformation plasticity effects, experiments with rings produced from austenitic steel (material SAE 304) were examined. In addition, conical rings were heat treated, since the ring geometry has a large influence on the temperature fields during heat treatment. The experimental results were compared with the theoretical description of distortion potential by strain analysis, to identify the necessary inhomogeneous distribution of different carriers of the distortion potential which lead to the observed change in roundness deviation.
Process integrated distortion compensation of large bearing rings
Authors: Stark P. , Fritsching U. , Hunkel M. , Hansmann D. 
Published: January 2012

AbstractBearing rings (d ⪈ 1000 mm, material: 42CrMo4) may be quenched directly after the hot rolling process with the use of adapted jet fields. Specific asymmetric cooling conditions for controlled heat treatment processes shall be utilized for distortion compensation. The feasibility of liquid quenching techniques (water jet cooling a) in water b) in ambient air and c) spray cooling) is investigated experimentally concerning the achievable cooling curves of the ring specimen and the resulting heat transfer coefficients on its surface. The influence of the distribution of the quenching intensities around the ring's circumference on the achievable distortion compensation behaviour is investigated both experimentally in a jet nozzle field and through numerical simulations.
Parameters of distortion in forging gear wheel blanks
Authors: Rentsch H. 
Published: January 2012

AbstractThe gear wheel manufacture is one of the key technologies for power train systems and in automotive industry. These complex high performance parts require stable processes and narrow tolerances in order to control the manufacturing costs. Experimental analyses show that the material flow in disk‐like gear wheel blanks made of 20MnCr5 can vary significantly. This is of significance as a correlation between the dishing after case‐hardening of the gear wheel blanks and the material flow was found. Besides experimental findings, finite element (FE) analyses of the influence of process parameters and perturbations on the distortion of forged gear wheel blanks have been carried out. A temperature gradient over the height of the workpiece is assumed to be largely responsible for the observed material flow variations and the related dishing of the forged gear wheel blanks.