bluuebunny/crossref_metadata_2025_split huggingface dataset:
The microtubule destabilizing protein stathmin controls the transition from dividing neuronal precursors to postmitotic neurons during adult hippocampal neurogenesis
Authors: Boekhoorn Karin , van Dis Vera , Goedknegt Erika , Sobel André , Lucassen Paul J. , Hoogenraad Casper C. 
Published: June 2014

ABSTRACTThe hippocampus is one of the two areas in the mammalian brain where adult neurogenesis occurs. Adult neurogenesis is well known to be involved in hippocampal physiological functions as well as pathophysiological conditions. Microtubules (MTs), providing intracellular transport, stability, and transmitting force, are indispensable for neurogenesis by facilitating cell division, migration, growth, and differentiation. Although there are several examples of MT‐stabilizing proteins regulating different aspects of adult neurogenesis, relatively little is known about the function of MT‐destabilizing proteins. Stathmin is such a MT‐destabilizing protein largely restricted to the CNS, and in contrast to its developmental family members, stathmin is also expressed at significant levels in the adult brain, notably in areas involved in adult neurogenesis. Here, we show an important role for stathmin during adult neurogenesis in the subgranular zone of the mouse hippocampus. After carefully mapping stathmin expression in the adult dentate gyrus (DG), we investigated its role in hippocampal neurogenesis making use of stathmin knockout mice. Although hippocampus development appears normal in these animals, different aspects of adult neurogenesis are affected. First, the number of proliferating Ki‐67+ cells is decreased in stathmin knockout mice, as well as the expression of the immature markers Nestin and PSA‐NCAM. However, newborn cells that do survive express more frequently the adult marker NeuN and have a more mature morphology. Furthermore, our data suggest that migration in the DG might be affected. We propose a model in which stathmin controls the transition from neuronal precursors to early postmitotic neurons. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 74: 1226–1242, 2014
Dickkopf‐3 alters the morphological response to retinoic acid during neuronal differentiation of human embryonal carcinoma cells
Authors: Alfonso Rocío Jiménez , Gorroño‐Etxebarria Irantzu , Rabano Miriam , Vivanco Maria dM. , Kypta Robert 
Published: June 2014

ABSTRACTDickkopf‐3 (Dkk‐3) and Dkkl‐1 (Soggy) are secreted proteins of poorly understood function that are highly expressed in subsets of neurons in the brain. To explore their potential roles during neuronal development, we examined their expression in Ntera‐2 (NT2) human embryonal carcinoma cells, which differentiate into neurons upon treatment with retinoic acid (RA). RA treatment increased the mRNA and protein levels of Dkk‐3 but not of Dkkl‐1. Ectopic expression of both Dkk‐3 and Dkkl‐1 induced apoptosis in NT2 cells. Gene silencing of Dkk‐3 did not affect NT2 cell growth or differentiation but altered their response to RA in suspension cultures. RA treatment of NT2 cells cultured in suspension resulted in morphological changes that led to cell attachment and flattening out of cell aggregates. Although there were no significant differences in the expression levels of cell adhesion molecules in control and Dkk‐3‐silenced cells, this morphological response was not observed in Dkk‐3‐silenced cells. These findings suggest that Dkk‐3 plays a role in the regulation of cell interactions during RA‐induced neuronal differentiation. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 74: 1243–1254, 2014
Selection based on the size of the black tie of the great tit may be reversed in urban habitats
Authors: Senar Juan Carlos , Conroy Michael J. , Quesada Javier , Mateos‐Gonzalez Fernando 
Published: June 2014

AbstractA standard approach to model how selection shapes phenotypic traits is the analysis of capture–recapture data relating trait variation to survival. Divergent selection, however, has never been analyzed by the capture–recapture approach. Most reported examples of differences between urban and nonurban animals reflect behavioral plasticity rather than divergent selection. The aim of this paper was to use a capture–recapture approach to test the hypothesis that divergent selection can also drive local adaptation in urban habitats. We focused on the size of the black breast stripe (i.e., tie width) of the great tit (Parus major), a sexual ornament used in mate choice. Urban great tits display smaller tie sizes than forest birds. Because tie size is mostly genetically determined, it could potentially respond to selection. We analyzed capture/recapture data of male great tits in Barcelona city (N = 171) and in a nearby (7 km) forest (N = 324) from 1992 to 2008 usingMARK. When modelling recapture rate, we found it to be strongly influenced by tie width, so that both for urban and forest habitats, birds with smaller ties were more trap‐shy and more cautious than their larger tied counterparts. When modelling survival, we found that survival prospects in forest great tits increased the larger their tie width (i.e., directional positive selection), but the reverse was found for urban birds, with individuals displaying smaller ties showing higher survival (i.e., directional negative selection). As melanin‐based tie size seems to be related to personality, and both are heritable, results may be explained by cautious personalities being favored in urban environments. More importantly, our results show that divergent selection can be an important mechanism in local adaptation to urban habitats and that capture–recapture is a powerful tool to test it.
A new method for measuring stand sapwood area in forests
Authors: Jaskierniak Dominik , Benyon Richard , Kuczera George , Robinson Andrew 
Published: June 2014

AbstractWe introduce a novel methodology for measuring stand sapwood area (SA), which provides a useful indicator of evapotranspiration from forest stands. The method is demonstrated in a 73‐year‐oldEucalyptus regnansforest comprising 784 stems over a 5 ha area. We used photos of stump cross‐sections to differentiate sapwood from heartwood and found 90% of stump segments to have a visible transition boundary. The digital images were corrected for lens distortion and scaled to an actual cross‐sectional area, with resulting stump perimeters corresponding well with field‐measured perimeters traced using string (root‐mean‐square error = 4 cm,R2 = 0.99). Calculated SA and basal area (BA) at stump height were coupled with tree and sapwood taper data to predict the SA:BA ratio at 1.3 m height (). Tree taper data were coupled with stump dimensions data in a mixed‐effects model to predict each stump's BA at 1.3 m, and sapwood taper data from buttress logs were used to improve each stems. Using this procedure, we found our study site to have anof 0.21 and total stand SA at 1.3 m height of 9.3 m2 ha−1.We quantified the bias in traditionalestimates that use cores to measure sapwood thickness and diameter tape to calculate SA. We show traditional methods underestimatethat increases with tree diameter and decreases with stem circularity, whereas our methodology gave more accurate measures of SA in large buttressing trees. Our methodology also provides a more efficient way of generating maps of SA variation across large forested catchments. Copyright © 2014 John Wiley & Sons, Ltd.
Changes to southern Appalachian water yield and stormflow after loss of a foundation species
Authors: Brantley Steven T. , Miniat Chelcy Ford , Elliott Katherine J. , Laseter Stephanie H. , Vose James M. 
Published: June 2014

AbstractFew studies have examined how insect outbreaks affect landscape‐level hydrologic processes. We report the hydrologic effects of the invasive, exotic hemlock woolly adelgid (HWA) in a headwater catchment in the southern Appalachian Mountains. The study watershed experienced complete mortality of an evergreen tree species, Tsuga canadensis (L.) Carr. (eastern hemlock), after infestation was first detected in 2003. Hemlock mortality resulted in a ~6% reduction in basal area in the watershed, and this loss was primarily concentrated in riparian zones. We used a paired‐watershed approach to quantify changes in water yield and peak stormflow using streamflow data from the infested watershed and a nearby watershed with significantly lower hemlock basal area. We hypothesized that yield would increase shortly after hemlock infestation but decrease over the longer‐term. We found that annual yield did not increase significantly in any year after infestation but decreased significantly by 12·0 cm (~8%) in 2010. Monthly yield also decreased after infestation, but changes were limited to the dormant season. The decline in yield is likely to persist as hemlock is replaced by species with higher transpiration rates. Peakflow increased significantly after infestation during the two largest flow events in the post‐infestation period. Changes in stormflow during extreme events may have been temporary as another evergreen, Rhododendron maximum, may have mitigated some of the changes after hemlock loss. Thus, streams draining watersheds where eastern hemlock has been lost due to HWA infestation demonstrate permanent reductions in yield and transient increases in peakflow during large‐flow events. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Sensory evaluation and gas chromatography–mass spectrometry (GC‐MS) analysis of the volatile extracts of pummelo (Citrus maxima) peel
Authors: Sun Hao , Ni Hui , Yang Yuanfan , Chen Feng , Cai Huinong , Xiao Anfeng 
Published: June 2014

ABSTRACTVolatile extracts were prepared from the peel of pummelo by cold pressing (CP), water distillation (WD), simultaneous distillation and extraction (SDE), microwave‐assisted extraction (MAE), ultrasonic‐assisted extraction (UAE) and supercritical CO2 fluid extraction (SFE). They were analysed by sensory evaluation and gas chromatography–mass spectrometry (GC‐MS). The former technique showed that the CP essential oil (CP‐EO), MAE and UAE extracts possessed similar odour profiles to the natural pummelo odour, whereas the SDE extract and WD essential oil (WD‐EO) presented the fermented/overripe and alcohol/pungent notes, and the SFE extract had a sweet note. Although the GC‐MS analyses revealed the six extracts had a certain degree of differences in their compositions, they had similar major volatiles, including limonene (301 476–497 028 µg/ml), β‐myrcene (86 400–230 400 µg/ml), β‐pinene (1370–7129 µg/ml), linalool (1916–4482 µg/ml) and germacrene D (1165–2327 µg/ml). Analyses of odour activity values (OAVs) and cluster analysis revealed the fermented/overripe and alcohol/pungent notes of the SDE extract and WD‐EO were attributed to nerol, geraniol and linalool oxide. The sweet note of the SFE extract was ascribed to citronellal and limonene oxide. Besides, a lack of limonene, neral and geranial resulted in a light green aroma of the SFE extract. This information might be valuable for further development of aromatically desirable products from citrus fruits. Copyright © 2014 John Wiley & Sons, Ltd.
A Brain‐wide association study of DISC1 genetic variants reveals a relationship with the structure and functional connectivity of the precuneus in schizophrenia
Authors: Gong Xiaohong , Lu Wenlian , Kendrick Keith M. , Pu Weidan , Wang Chu , Jin Li , Lu Guangmin , Liu Zhening , Liu Haihong , Feng Jianfeng 
Published: June 2014

AbstractThe Disrupted in Schizophrenia Gene 1 (DISC1) plays a role in both neural signaling and development and is associated with schizophrenia, although its links to altered brain structure and function in this disorder are not fully established. Here we have used structural and functional MRI to investigate links with six DISC1 single nucleotide polymorphisms (SNPs). We employed a brain‐wide association analysis (BWAS) together with a Jacknife internal validation approach in 46 schizophrenia patients and 24 matched healthy control subjects. Results from structural MRI showed significant associations between all six DISC1 variants and gray matter volume in the precuneus, post‐central gyrus and middle cingulate gyrus. Associations with specific SNPs were found for rs2738880 in the left precuneus and right post‐central gyrus, and rs1535530 in the right precuneus and middle cingulate gyrus. Using regions showing structural associations as seeds a resting‐state functional connectivity analysis revealed significant associations between all 6 SNPS and connectivity between the right precuneus and inferior frontal gyrus. The connection between the right precuneus and inferior frontal gyrus was also specifically associated with rs821617. Importantly schizophrenia patients showed positive correlations between the six DISC‐1 SNPs associated gray matter volume in the left precuneus and right post‐central gyrus and negative symptom severity. No correlations with illness duration were found. Our results provide the first evidence suggesting a key role for structural and functional connectivity associations between DISC1 polymorphisms and the precuneus in schizophrenia. Hum Brain Mapp 35:5414–5430, 2014. © 2014 Wiley Periodicals, Inc.
A mechanistic in vitro study of the microgalvanic degradation of secondary phase particles in magnesium alloys
Authors: Walter R. , Kannan M. Bobby 
Published: June 2014

AbstractThe aim of this work was to understand the effect of microgalvanic degradation on secondary phase particles in magnesium alloys under in vitro condition. Pure magnesium and Mg17Al12 (β‐phase) were galvanically coupled in simulated body fluid and the degradation behavior was studied using electrochemical impedance spectroscopy. The galvanic coupling produced a phosphate/carbonate layer on the β‐phase, which initially increased the degradation resistance. However, the deposited phosphate/carbonate layer rapidly degraded once the galvanic coupling was removed, and β‐phase exhibited similar degradation resistance to that of pure magnesium. A phenomenological model has been presented, demonstrating the galvanic coupling effect. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 990–1000, 2015.
Biointegration of corneal macroporous membranes based on poly(ethyl acrylate) copolymers in an experimental animal model
Authors: Alió del Barrio Jorge L. , Chiesa Massimo , Gallego Ferrer Gloria , Garagorri Nerea , Briz Nerea , Fernandez‐Delgado Jorge , Sancho‐Tello Valls Maria , Botella Carmen Carda , García‐Tuñón Ignacio , Bataille Laurent , Rodriguez Alejandra , Arnalich‐Montiel Francisco , Gómez Ribelles Jose L. , Antolinos‐Turpín Carmen M. , Gómez‐Tejedor Jose A. , Alió Jorge L. , De Miguel Maria P. 
Published: June 2014

AbstractCurrently available keratoprosthesis models (nonbiological corneal substitutes) have a less than 75% graft survival rate at 2 years. We aimed at developing a model for keratoprosthesis based on the use of poly(ethyl acrylate) (PEA)‐based copolymers, extracellular matrix‐protein coating and colonization with adipose‐derived mesenchymal stem cells. Human adipose tissue derived mesenchymal stem cells (h‐ADASC) colonization efficiency of seven PEA‐based copolymers in combination with four extracellular matrix coatings were evaluated in vitro. Then, macroporous membranes composed of the optimal PEA subtypes and coating proteins were implanted inside rabbit cornea. After a 3‐month follow‐up, the animals were euthanized, and the clinical and histological biointegration of the implanted material were assessed. h‐ADASC adhered and survived when cultured in all PEA‐based macroporous membranes. The addition of high hydrophilicity to PEA membranes decreased h‐ADASC colonization in vitro. PEA‐based copolymer containing 10% hydroxyethyl acrylate (PEA‐HEA10) or 10% acrylic acid (PEA‐AAc10) monomeric units showed the best cellular colonization rates. Collagen plus keratan sulfate‐coated polymers demonstrated enhanced cellular colonization respect to fibronectin, collagen, or uncoated PEAs. In vivo implantation of membranes resulted in an extrusion rate of 72% for PEA, 50% for PEA‐AAc10, but remarkably of 0% for PEA‐HEA10. h‐ADASC survival was demonstrated in all the membranes after 3 months follow‐up. A slight reduction in the extrusion rate of h‐ADASC colonized materials was observed. No significant differences between the groups with and without h‐ADASC were detected respect to transparency or neovascularization. We propose PEA with low hydroxylation as a scaffold for the anchoring ring of future keratoprosthesis. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1106–1118, 2015.
Extracellular matrix elasticity and topography: Material‐based cues that affect cell function via conserved mechanisms
Authors: Janson Isaac A. , Putnam Andrew J. 
Published: June 2014

AbstractChemical, mechanical, and topographic extracellular matrix (ECM) cues have been extensively studied for their influence on cell behavior. These ECM cues alter cell adhesion, cell shape, and cell migration and activate signal transduction pathways to influence gene expression, proliferation, and differentiation. ECM elasticity and topography, in particular, have emerged as material properties of intense focus based on strong evidence these physical cues can partially dictate stem cell differentiation. Cells generate forces to pull on their adhesive contacts, and these tractional forces appear to be a common element of cells' responses to both elasticity and topography. This review focuses on recently published work that links ECM topography and mechanics and their influence on differentiation and other cell behaviors. We also highlight signaling pathways typically implicated in mechanotransduction that are (or may be) shared by cells subjected to topographic cues. Finally, we conclude with a brief discussion of the potential implications of these commonalities for cell based therapies and biomaterial design. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1246–1258, 2015.
A novel pH‐responsive interpolyelectrolyte hydrogel complex for the oral delivery of levodopa. Part II: Characterization and formulation of an IPEC‐based tablet matrix
Authors: Ngwuluka Ndidi C. , Choonara Yahya E. , Kumar Pradeep , du Toit Lisa C. , Khan Riaz A. , Pillay Viness 
Published: June 2014

AbstractThis study was undertaken in order to apply a synthesized interpolyelectrolyte complex (IPEC) of polymethacrylate and carboxymethylcellulose as a controlled release oral tablet matrix for the delivery of the model neuroactive drug levodopa. The IPEC (synthesized in Part I of this work) was characterized by techniques such as Fourier Transform Infra‐Red (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), Advanced DSC (ADSC), and Scanning Electron Microscopy (SEM). The tablet matrices were formulated and characterized for their drug delivery properties and in vitro drug release. FTIR confirmed the interaction between the two polymers. The IPEC composite generated tablet matrices with a hardness ranging from 19.152–27.590 N/mm and a matrix resilience ranging between 42 and 46%. An IPEC of polymethacrylate and carboxymethylcellulose was indeed an improvement on the inherent properties of the native polymers providing a biomaterial with the ability to release poorly soluble drugs such as levodopa at a constant rate over a prolonged period of time. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1085–1094, 2015.
A novel pH‐responsive interpolyelectrolyte hydrogel complex for the oral delivery of levodopa. Part I. IPEC modeling and synthesis
Authors: Ngwuluka Ndidi C. , Choonara Yahya E. , Kumar Pradeep , du Toit Lisa C. , Khan Riaz A. , Pillay Viness 
Published: June 2014

AbstractThis study was undertaken to synthesize an interpolyelectrolyte complex (IPEC) of polymethacrylate (E100) and sodium carboxymethylcellulose (NaCMC) to form a polymeric hydrogel material for application in specialized oral drug delivery of sensitive levodopa. Computational modeling was employed to proffer insight into the interactions between the polymers. In addition, the reactional profile of NaCMC and polymethacrylate was elucidated using molecular mechanics energy relationships (MMER) and molecular dynamics simulations (MDS) by exploring the spatial disposition of NaCMC and E100 with respect to each other. Computational modeling revealed that the formation of the IPEC was due to strong ionic associations, hydrogen bonding, and hydrophilic interactions. The computational results corroborated well with the experimental and the analytical data. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1077–1084, 2015.
How can bioactive glasses be useful in ocular surgery?
Authors: Baino Francesco 
Published: June 2014

AbstractIn the last few decades, the introduction of bioactive glasses (BGs), a special class of bioceramics that are able to bond to living tissues stimulating new tissue growth, has improved both treatment procedures via reconstructive surgery and the quality of life of rehabilitated patients in orthopedics and dentistry. While BGs have been extensively investigated for applications in these two surgical fields, there has been relatively little research on their use in other medical areas. Glass has been used for centuries to produce external refractive lenses and the intraocular implantation of small glass disks to correct visual deficiencies has been documented since the mid 1700s. Moreover, some evidences reported in the recent literature seem to demonstrate that the success of three specific types of ophthalmic devices, that is, synthetic grafts for eye orbit bone repair, orbital implants replacing the whole ocular globe and keratoprostheses (artificial cornea), could significantly benefit by the use of BG. A prospective view as well as a state‐of‐the‐art review on this topic are currently lacking in the literature. The present article aims to give a comprehensive picture of the BG‐based implants that have been developed in the context of ocular surgery; the strengths and shortcomings of the existing devices are outlined in order to provide useful stimuli for future research. Promising research directions are also proposed, emphasizing the added values that BGs could carry in ophthalmology in the light of recent findings in tissue engineering and regenerative medicine. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1259–1275, 2015.
Wear of nanofilled dental composites at varying filler concentrations
Authors: Lawson Nathaniel C. , Burgess John O. 
Published: June 2014

AbstractThe aim of this study is to examine the effects of nanofiller concentration on the mechanisms of wear of a dental composite. Nanofilled composites were fabricated with a bisphenol A glycidyl methacrylate polymer and 40 nm SiO2 filler particles at three filler loads (25, 50, and 65 wt %). The elastic modulus, flexural strength, and hardness of the composites and the unfilled resin were measured. The materials (n = 8) were tested in the modified wear testing device at 50,000, 100,000, and 200,000 cycles with 20N force at 1 Hz. A 33% glycerine lubricant and stainless steel antagonist were used. The worn composite and antagonist surfaces were analyzed with noncontact profilometry and SEM. The volumetric wear data indicated that there are significant differences between filler concentrations and cycles (p < 0.05). A trend was noted that increasing filler content beyond 25% decreased the wear resistance of the composites. Increasing filler content increased hardness and modulus and increased flexural strength up to 50% fill. SEM evaluation of the worn specimens indicated that the resin and 25% filled materials exhibited cracking and failed by fatigue and the 50 and 65% filled materials exhibited microcutting and failed by abrasive wear. Based on the results of this study, composite manufacturers are recommended to use a filler concentration between 25 and 50% when using nanosized filler particles. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 424–429, 2015.