bluuebunny/crossref_metadata_2025 huggingface dataset:
Diurnal variability of low clouds in the Southeast Pacific simulated by a multiscale modeling framework model
Authors: Cheng Anning , Xu Kuan‐Man
Published: July 2013

This study analyzes the diurnal variations of austral‐spring stratocumulus clouds in the Southeast Pacific and their physical mechanisms from a global multiscale modeling framework (MMF) simulation. This MMF contains an advanced third‐order turbulence closure in its cloud‐resolving model component, helping it to realistically simulate boundary layer turbulence and low‐level clouds. The main finding is that the MMF simulation can reproduce the spatial pattern of the diurnal variations of low clouds within the region, with the day‐night cloud fraction (CF) differences ranging from 0.10 at 30° off the shore to 0.40 near the shore. The diurnal phases and ranges of simulated liquid water path, CF, and surface cloud radiative effects agree well with available observations. The maximum CF occurs in the early morning and the minimum in the late afternoon over the open ocean. However, near the shore, the maximum/minimum CF anomalies are more variable. The spatial variability of the diurnal variations is attributed to the modulation of solar‐forced variation by the orographically induced circulation. The solar radiation makes the lower cloud layer dissipated during the day, and clouds recover first there in the early evening, with the upper cloud layer changing relatively less in cloudiness. The southwestward propagating upsidence wave that is related to the orographical forcing modulates the CF anomalies near the shore. The orographically induced subsidence, however, extends too deeply into the boundary layer because of the model's unrealistically smooth topography, and it dissipates rather than enhances the stratocumulus near the shore between the late night and the following noon.
Tropical water vapor variations during the 2006–2007 and 2009–2010 El Niños: Satellite observation and GFDL AM2.1 simulation
Authors: Takahashi Hanii , Su Hui , Jiang Jonathan H. , Luo Zhengzhao Johnny , Xie Shang‐Ping , Hafner Jan
Published: July 2013

Water vapor measurements from Aura Microwave Limb Sounder (MLS, above 300 hPa) and Aqua Atmospheric Infrared Sounder (AIRS, below 300 hPa) are analyzed to study the variations of moisture during the 2006–2007 and 2009–2010 El Niños. The 2006–2007 El Niño is an East Pacific (EP) El Niño, while the 2009–2010 El Niño is a Central Pacific (CP) El Niño or El Niño Modoki. Results show that these two types of El Niño events produce different patterns of water vapor anomalies over the tropical ocean, approximately resembling the cloud anomalies shown in Su and Jiang (2013). Regression of water vapor anomalies onto the Niño‐3.4 SST for the A‐Train period shows a clear “upper tropospheric amplification” of the fractional water vapor change, i.e., the ratio of the change in specific humidity to the layer‐averaged specific humidity. Furthermore, tropical water vapor anomalies in different circulation regimes are examined. It is shown that the variations of water vapor during the 2006–2007 El Niño are mainly controlled by the thermodynamic component, whereas both dynamic and thermodynamic components control the water vapor anomalies during the 2009–2010 El Niño. GFDL AM2.1 model simulations of water vapor and cloud anomalies for the two El Niños are compared with the satellite observations. In general, the model approximately reproduces the water vapor anomalies on both zonal and meridional planes but it produces too strong a cloud response in the mid‐ and lower troposphere. The model fails to capture the dynamic component of water vapor anomalies, particularly over the Indian Ocean.
Flow and sediment suspension events over low‐angle dunes: Fraser Estuary, Canada
Authors: Bradley R.W. , Venditti J. G. , Kostaschuk R. A. , Church M. , Hendershot M. , Allison M. A.
Published: July 2013

The morphodynamics of large sand‐bedded rivers and estuaries are ultimately controlled by the way bed material is moved and the development of large, subaqueous sand dunes that control hydraulic flow resistance. It is widely thought that the primary mechanism for moving sandy bed material in these channels is large‐scale coherent flow structures that cause suspension events whose properties vary with flow, especially in tidally influenced environments. Here, we examine mean flow and sediment suspension events over low‐angle dunes (lee face angle <30°) in the unsteady flow of the Fraser Estuary, Canada. At high tide, flow nearly ceased and a salt wedge entered the channel, forcing salt water under the downstream‐moving fresh water. The salt wedge persisted in the channel until late in the falling tide, causing stratification in the water column and instabilities along the saline‐fresh water interface. At low tide, mean velocities peaked and forced the saline water out of the channel. Flow over the low‐angle dunes displayed topographically induced patterns previously observed over high‐angle dunes, but permanent flow separation was not observed. Large‐scale sediment suspension events dominated sediment flux during low tide and became larger scale, yet less frequent, as the tide began to rise. The suspension events appeared to form over the lower stoss of the dunes and grew up over the bed forms and, less commonly, emerged downstream of the crest. Suspension events move ~69% of the total sediment in the flow above low‐angle dunes when they are present.
The global NPP dependence on ENSO: La Niña and the extraordinary year of 2011
Authors: Bastos A. , Running Steven W. , Gouveia Célia , Trigo Ricardo M.
Published: July 2013

Global ecosystems remove about 25% of anthropogenic CO2 emissions; however, the response of the land sink to climate variability and change is not yet fully understood. In 2011, the highest global value of net primary production (NPP) since 2000 was registered on the Moderate Resolution Imaging Spectroradiometer record, together with the highest value on the Carbon Dioxide Information Analysis Center record of carbon land sink strength since 1959. Here we show that El Niño/Southern Oscillation (ENSO) is responsible for much of the variability observed in the land sink and that the high NPP anomaly observed in 2011 was largely influenced by the strongest La Niña since the 1970s that lasted from late 2010 to early 2012. ENSO explains more than 40% of global NPP variability, mainly driven by the response of Southern Hemisphere ecosystems, particularly in tropical and subtropical regions. Water availability, controlled by temperature and precipitation anomalies, appears to be the main factor driving the regional response of NPP to ENSO.
Mass spectrometry and NMR analysis of ligand binding by human liver fatty acid binding protein
Authors: Santambrogio C. , Favretto F. , D'Onofrio M. , Assfalg M. , Grandori R. , Molinari H.
Published: July 2013

Human liver fatty acid binding protein (hL‐FABP) is the most abundant cytosolic protein in the liver. This protein plays important roles associated to partitioning of fatty acids (FAs) to specific metabolic pathways, nuclear signaling and protection against oxidative damage. The protein displays promiscuous binding properties and can bind two internal ligands, unlike FABPs from other tissues. Different topologies for the ligand located in the more accessible site have been reported, with either a ‘head‐in’ or ‘head‐out’ orientation of the carboxylate end. Electrospray‐ionization mass spectrometry and nuclear magnetic resonance titrations are employed here in order to investigate in further detail the binding properties of this system, the equilibria established in solution and the pH dependence of the complexes. The results are consistent with two binding sites with different affinity and a unique head‐out topology for the second molecule of either ligand. Competition experiments indicate a higher affinity for oleic acid relative to palmitic acid at each binding site. Copyright © 2013 John Wiley & Sons, Ltd.
Clinico‐pathological significance of hepatitis C virus core antigen levels in chronic infection
Authors: Durante‐Mangoni Emanuele , Vallefuoco Luca , Sorrentino Rosanna , Iossa Domenico , Perna Enzo , Molaro Rosa , Braschi Umberto , Zampino Rosa , Sodano Giuseppe , Adinolfi Luigi Elio , Utili Riccardo , Portella Giuseppe
Published: July 2013

Hepatitis C virus core antigen (HCVcoreAg) may be measured in serum with a sensitive, recently validated assay. Beyond its value as a marker of viral infection, there are little data on its relation with clinical, histological, and virological parameters. In this study, the significance of HCVcoreAg levels was studied in a prospective cohort of 114 patients with chronic hepatitis C. HCVcoreAg was measured by a commercial chemiluminescent microparticle immunoassay. Clinical and virological data included quantitative HCV‐RNA, HCV genotype, ALT, GGT, IL28B rs12979860 polymorphism as well as liver histology parameters. HCVcoreAg levels were correlated significantly with HCV‐RNA (r = 0.56; P < 0.0001) but also with ALT levels (r = 0.258; P < 0.01) and liver necroinflammatory activity (r = 0.205; P < 0.04). Patients harbouring HCV genotype 3 showed lower levels of HCVcoreAg than both genotype 1 and two patients. In genotype 3, a direct correlation between steatosis and HCVcoreAg was found. Levels of HCVcoreAg also varied according to the IL28B genotype. These data suggest that the evaluation of HCVcoreAg serum levels may provide relevant data for the baseline clinical evaluation of chronic hepatitis C patients. HCVcoreAg serum levels may be a useful tool to further the understanding of chronic hepatitis C pathobiology. J Med. Virol. 85:1913–1918, 2013. © 2013 Wiley Periodicals, Inc.
Dual Functionalized Graphene Oxide Serves as a Carrier for Delivering Oligohistidine‐ and Biotin‐Tagged Biomolecules into Cells
Authors: Jana Batakrishna , Mondal Goutam , Biswas Atanu , Chakraborty Indrani , Saha Abhijit , Kurkute Prashant , Ghosh Surajit
Published: July 2013

A versatile method of dual chemical functionalization of graphene oxide (GO) with Tris‐[nitrilotris(acetic acid)] (Tris‐NTA) and biotin for cellular delivery of oligohistidine‐ and biotin‐tagged biomolecules is reported. Orthogonally functionalized GO surfaces with Tris‐NTA and biotin to obtain a dual‐functionalized GO (DFGO) are prepared and characterized by various spectroscopic and microscopic techniques. Fluorescence microscopic images reveal that DFGO surfaces are capable of binding oligohistidine‐tagged biomolecules/proteins and avidin/biotin‐tagged biomolecules/proteins orthogonally. The DFGO nanoparticles are non‐cytotoxic in nature and can deliver oligohistidine‐ and biotin‐tagged biomolecules simultaneously into the cell.
Self‐assembling Linear and Star Shaped Poly(ϵ‐caprolactone)/poly[(meth)acrylic acid] Block Copolymers as Carriers of Indomethacin and Quercetin
Authors: Bury Katarzyna , Du Prez Filip , Neugebauer Dorota
Published: July 2013

A amphiphilic linear AB, BAB, and star shaped (AB)3 block copolymers of poly(ϵ‐caprolactone) (PCL)/poly(meth)acrylic acid (P(M)AA) are used for the preparation of nanoparticles and drug entrapment, where indomethacin and quercetin are employed as model drugs. Drug loading experiments with the nanoparticles based on PAA block copolymers demonstrate a higher efficiency for the star structure, whereas the PMAA star copolymer presents the lowest entrapment ability. The release properties are studied at room temperature and 37 °C in phosphate buffer solutions with pH equal to 5 and 7.4. The kinetic profiles show a strong relation to the copolymer's topology, indicating the lowest release rates from the star based superstructures, while the PMAA particles are less stable than those containing PAA segment(s).
Novel Cyclopentadithiophene‐Based D–A Copolymers for Organic Photovoltaic Cell Applications
Authors: Drozdov Fedor V. , Myshkovskaya Ekaterina N. , Susarova Diana K. , Troshin Pavel A. , Fominykh Olga D. , Balakina Marina Yu. , Bakirov Artem V. , Shcherbina Maxim A. , Choi Jinwoo , Tondelier Denis , Buzin Mikhail I. , Chvalun Sergei N. , Yassar Abderrahim , Ponomarenko Sergei A.
Published: July 2013

Here, the synthesis, characterization, and photovoltaic properties of four new donor–acceptor copolymers are reported. These copolymers are based on 4,4‐difluoro‐cyclopenta[2,1‐b:3,4‐b′] dithiophene as an acceptor unit and various donor moieties: 4,4‐dialkyl derivatives of 4H‐cyclopenta[2,1‐b:3,4‐b′]dithiophene and its silicon analog, dithieno[3,2‐b:2′,3′‐d]‐silol. These copolymers have an almost identical bandgap of 1.7 eV and have a HOMO energy level that varies from −5.34 to −5.73 eV. DSC and X‐ray diffraction (XRD) investigations reveal that linear octyl substituents promote the formation of ordered layered structures, while branched 2‐ethylhexyl substituents lead to amorphous materials. Polymer solar cells based on these copolymers as donor and PC61BM as acceptor components yield a power conversion efficiency of 2.4%.

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Crosslinked Aromatic Polyamides: A Further Step in High‐Performance Materials
Authors: Trigo‐López Miriam , Barrio‐Manso José L. , Serna Felipe , García Félix C. , García José M.
Published: July 2013

This work aims to improve the outstanding thermal and mechanical properties of commercialized wholly aromatic polyamide fibers (i.e., aramids), by crosslinking the materials. The introduction of a reactive azide group into the polymer structure leads to functional aramids. Crosslinking processes can be easily performed using an inexpensive thermal treatment after fiber spinning with current spin production facilities.

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Hypersurfaces with parallel para‐Laguerre tensor in
Authors: Shu Shichang
Published: July 2013

Let be an ‐dimensional hypersurface with vanishing Laguerre form in , be the Laguerre second fundamental form and be the Laguerre tensor of the immersion x. We define a symmetric (0, 2) tensor which is so‐called the para‐Laguerre tensor of x, where λ is a constant. If , we say that x is of parallel para‐Laguerre tensor, where ∇ is the Levi‐Civita connection of the Laguerre metric g. An eigenvalue of the para‐Laguerre tensor is called a para‐Laguerre eigenvalue of x. The aim of this paper is to classify all oriented hypersurfaces in with parallel para‐Laguerre tensor or with three distinct constant para‐Laguerre eigenvalues one of which is simple.
Influence of Polyol Molecular Weight and Type on the Tack and Peel Properties of Waterborne Polyurethane Pressure‐Sensitive Adhesives
Authors: Akram Nadia , Gurney Robert S. , Zuber Mohammad , Ishaq Muhammad , Keddie Joseph L.
Published: July 2013

A requirement for optimum performance in a pressure‐sensitive adhesive (PSA) is the right balance between viscous and elastic properties, achieved by controlling the molecular architecture. Here, waterborne polyurethane PSAs are synthesized using a blend of polyether and polyalkene‐based polyols. The effects of the polyol type and molecular weight on the adhesive and thermomechanical properties are explored to optimize them for PSA applications. A linear polyurethane is synthesized by the reaction of an aliphatic diisocyanate with a diol blend of polypropylene glycol (PPG) and hydroxyl‐terminated polybutadiene (HTPB). With increasing concentrations of flexible HTPB segments and the associated increased viscous dissipation a favorable increase in the tack adhesion energy and peel strength is obtained. Adhesive properties are improved with increasing PPG molecular weight because chain entanglements become possible in the soft segments and raise the storage modulus.
Anxiety, depression and related factors in family caregivers of newly diagnosed lung cancer patients before first treatment
Authors: Lee Yun‐Hsiang , Liao Yu‐Chien , Liao Wei‐Yu , Shun Shiow‐Ching , Liu Yu‐Chun , Chan Jui‐Chun , Yu Chong‐Jen , Yang Pan‐Chyr , Lai Yeur‐Hur
Published: July 2013

Objective

This study aimed to (i) explore the prevalence and levels (severity) of anxiety and depression in family caregivers (FCs) of patients newly diagnosed with advanced lung cancer (stage IIIb or IV) before first treatment, and (ii) identify the factors related to FCs' anxiety and depression.

Methods

For this cross‐sectional study, 106 patient–FC dyads were recruited from a medical center in northern Taiwan. FCs' anxiety and depression were measured using the self‐report Hospital Anxiety and Depression Scale, and FCs' ability to manage patients' symptoms was assessed using the Self‐Efficacy in Symptom Management Scale. FCs' risks for anxiety and depression were separately identified using two multivariate logistic regression models.

Results

This study found two major results. First, before patients' first treatment, 50.9% and 32.1% of FCs were at risk for anxiety and depression, respectively. FCs' overall mean anxiety and depression scores were 7.7 (SD = 4.7) and 6.1 (SD = 4.5), respectively. Second, both FCs' anxiety and depression were significantly related to four factors: caring for another sick family member, younger age, having pain problems, and lower self‐efficacy in managing symptoms.

Conclusion

Family caregivers of patients newly diagnosed with advanced lung cancer had anxiety and depression before the patients' first treatment. We strongly suggest developing and testing interventions to reduce FCs' psychological distress and enhance their quality of life, thus ensuring better quality of patient care. Copyright © 2013 John Wiley & Sons, Ltd.
‘You know I've joined your club… I'm the hot flush boy’: a qualitative exploration of hot flushes and night sweats in men undergoing androgen deprivation therapy for prostate cancer
Authors: Eziefula C. U. , Grunfeld E. A. , Hunter M. S.
Published: July 2013

Objective

Hot flushes and night sweats are common amongst menopausal women, and psychological interventions for managing these symptoms have recently been developed for women. However, flushes in men with prostate cancer, which commonly occur following androgen deprivation therapy (ADT), remain under‐researched. This study is a qualitative exploration of flush‐related cognitive appraisals and behavioural reactions reported by a sample of these men.

Methods

Semi‐structured, in‐depth interviews were conducted with 19 men who were experiencing flushes after receiving ADT for prostate cancer. Framework analysis was used to generate and categorise emergent themes and explore associations between themes.

Results

Five main cognitive appraisals included the following: changes in oneself, impact on masculinity, embarrassment/social‐evaluative concerns, perceived control and acceptance/adjustment. There were men who held beliefs about the impact of flushes on their perceptions of traditional gender roles, who experienced shame and embarrassment due to concerns about the salience of flushes and perceptions by others and who experienced feelings of powerlessness over flushes. Powerlessness was associated with beliefs about the potentially fatal consequences of discontinuing treatment. Two other dominant themes included awareness/knowledge about flushes and management strategies. Experiences of flushes appeared to be influenced by upbringing and general experiences of prostate cancer and ADT.

Conclusions

The range of men's appraisals of, and reactions to, flushes generated from this qualitative exploration were broadly similar to those of menopausal women but differed in terms of the influence of masculinity beliefs. These findings could be used to inform future research and psychological interventions in this under‐researched field. Copyright © 2013 John Wiley & Sons, Ltd.
Crosslinking of a Gelatin Solutions Induced by Pulsed Electrical Discharges in Solutions
Authors: Prasertsung Isarawut , Damrongsakkul Siriporn , Saito Nagahiro
Published: July 2013

This study uses discharges in solutions for the treatment of gelatin solutions in order to generate crosslinking. The effects of plasma on the properties of gelatin solutions were investigated, the latter including viscosity, amino acid contents, chemical analyses, and gel strengths. The results show that, after short duration plasma treatments (5–10 min), the viscosity of the gelatin solutions increased, while the concentration of OH· free radicals decreased. After adding ethanol to the gelatin solutions, a greater increase in viscosity, and a greater decrease in free radicals were found. This suggests that ethanol provides more free radicals that can promote the crosslinking of the gelatin solution during the plasma treatment, resulting in higher viscosity. The gel strength of the gelatin was greatly enhanced by the plasma treatment of the solution. The results regarding the free amino acid contents showed that the crosslinking degree of plasma‐treated gelatin was higher than that of the untreated gelatin. FTIR measurements show that after plasma treatment, the IR bands at 1 668 and 1 558 cm−1, corresponding to the amide I and II groups of gelatin, shifted to higher wavenumbers, i.e. 1 672 and 1 564 cm−1, respectively. This suggests that crosslinking has occurred between gelatin molecules. The results show that discharges in solutions may be able to induce crosslinking reactions in the gelatin. Electrical discharges in solutions can be chemical‐free, alternative crosslinking methods.
The influence of annealing on the bimodal distribution of blocking temperatures of exchange biased bilayers
Authors: Ventura J. , Teixeira J. M. , Paz E. , Amaral J. S. , Costa J. D. , Apolinario A. , Araujo J. P. , Cardoso S. , Ferreira R. , Freitas P. P.
Published: July 2013

The exchange bias effect at the interface between antiferromagnetic (AFM) and ferromagnetic (FM) layers is of paramount importance in state‐of‐the‐art spintronic devices. However, a complete account of the physics behind exchange bias remains elusive and new effects are constantly unraveled. In particular, a bimodal distribution of blocking temperatures $ (T_{\rm B})$ was recently discovered, associated with the bulk of the AFM layer and interfacial AFM/FM regions with spin‐glass‐like properties. Here we study exchange bias in MnIr (25, 60 Å)/CoFe (50 Å) bilayers annealed at high temperatures (623 K and 673 K). We observe, for all samples and annealing temperatures, the existence of a large exchange bias variation at low temperatures associated with interfacial disorder. Such variation is more significative in the thinnest samples, where it is found to be independent on annealing temperature. On the other hand, in the thickest samples the contribution of the low temperature distribution largely increases with annealing temperature, due to enhanced disorder arising from Mn diffusion. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Oxygen vacancy dominant strong visible photoluminescence from BiFeO3 nanotubes
Authors: Miriyala N. , Prashanthi K. , Thundat T.
Published: July 2013

In this Letter, we report oxygen vacancy dominant strong visible photoluminescence (PL) from multiferroic BiFeO3(BFO) nanotubes (NTs) prepared by sol–gel template method. Abundant oxygen vacancies present in BFO NTs provide alternate paths for the photo‐induced carrier generation and recombination thus affecting the PL and photoabsorption characteristics. This study not only assists in understanding the optoelectronic characteristics of BFO NTs at nanoscale but also suggests BFO nanostructures as potential candidates for future photonic and sensing applications. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron Field Emission Enhancement of Vertically Aligned Ultrananocrystalline Diamond‐Coated ZnO Core–Shell Heterostructured Nanorods
Authors: Sankaran Kamatchi Jothiramalingam , Afsal Manekkathodi , Lou Shiu‐Cheng , Chen Huang‐Chin , Chen Chulung , Lee Chi‐Young , Chen Lih‐Juann , Tai Nyan‐Hwa , Lin I‐Nan
Published: July 2013

Enhanced electron field emission (EFE) behavior of a core–shell heterostructure, where ZnO nanorods (ZNRs) form the core and ultrananocrystalline diamond needles (UNCDNs) form the shell, is reported. EFE properties of ZNR‐UNCDN core–shell heterostructures show a high emission current density of 5.5 mA cm−2 at an applied field of 4.25 V μm−1, and a low turn‐on field of 2.08 V μm−1 compared to the 1.67 mA cm−2 emission current density (at an applied field of 28.7 V μm−1) and 16.6 V μm−1 turn‐on field for bare ZNRs. Such an enhancement in the field emission originates from the unique materials combination, resulting in good electron transport from ZNRs to UNCDNs and efficient field emission of electrons from the UNCDNs. The potential application of these materials is demonstrated by the plasma illumination measurements that lowering the threshold voltage by 160 V confirms the role of ZNR‐UNCDN core–shell heterostructures in the enhancement of electron emission.
Automating the maintenance of nonfunctional system properties using demonstration‐based model transformation
Authors: Sun Yu , Gray Jeff , Delamare Romain , Baudry Benoit , White Jules
Published: July 2013

Domain‐Specific Modeling Languages (DSMLs) are playing an increasingly significant role in software development. By raising the level of abstraction using notations that are representative of a specific domain, DSMLs allow the core essence of a problem to be separated from irrelevant accidental complexities, which are typically found at the implementation level in source code. In addition to modeling the functional aspects of a system, a number of nonfunctional properties (e.g., quality of service constraints and timing requirements) also need to be integrated into models in order to reach a complete specification of a system. This is particularly true for domains that have distributed real time and embedded needs. Given a base model with functional components, maintaining the nonfunctional properties that crosscut the base model has become an essential modeling task when using DSMLs.

The task of maintaining nonfunctional properties in DSMLs is traditionally supported by manual model editing or by using model transformation languages. However, these approaches are challenging to use for those unfamiliar with the specific details of a modeling transformation language and the underlying metamodel of the domain, which presents a7 steep learning curve for many users. This paper presents a demonstration‐based approach to automate the maintenance of nonfunctional properties in DSMLs. Instead of writing model transformation rules explicitly, users demonstrate how to apply the nonfunctional properties by directly editing the concrete model instances and simulating a single case of the maintenance process. By recording a user's operations, an inference engine analyzes the user's intention and generates generic model transformation patterns automatically, which can be refined by users and then reused to automate the same evolution and maintenance task in other models. Using this approach, users are able to automate the maintenance tasks without learning a complex model transformation language. In addition, because the demonstration is performed on model instances, users are isolated from the underlying abstract metamodel definitions. Our demonstration‐based approach has been applied to several scenarios, such as auto scaling and model layout. The specific contribution in this paper is the application of the demonstration‐based approach to capture crosscutting concerns representative of aspects at the modeling level. Several examples are presented across multiple modeling languages to demonstrate the benefits of our approach. Copyright © 2013 John Wiley & Sons, Ltd.
No evidence for neo-oogenesis may link to ovarian senescence in adult monkey
Authors: Yuan Jihong , Zhang Dongdong , Wang Lei , Liu Mengyuan , Mao Jian , Yin Yu , Ye Xiaoying , Liu Na , Han Jihong , Gao Yingdai , Cheng Tao , Keefe David L. , Liu Lin
Published: July 2013

Female germline or oogonial stem cells transiently residing in fetal ovaries are analogous to the spermatogonial stem cells or germline stem cells (GSCs) in adult testes where GSCs and meiosis continuously renew. Oocytes can be generated in vitro from embryonic stem cells and induced pluripotent stem cells, but the existence of GSCs and neo-oogenesis in adult mammalian ovaries is less clear. Preliminary findings of GSCs and neo-oogenesis in mice and humans have not been consistently reproducible. Monkeys provide the most relevant model of human ovarian biology. We searched for GSCs and neo-meiosis in ovaries of adult monkeys at various ages, and compared them with GSCs from adult monkey testis, which are characterized by cytoplasmic staining for the germ cell marker DAZL and nuclear expression of the proliferative markers PCNA and KI67, and pluripotency-associated genes LIN28 and SOX2, and lack of nuclear LAMIN A, a marker for cell differentiation. Early meiocytes undergo homologous pairing at prophase I distinguished by synaptonemal complex lateral filaments with telomere perinuclear distribution. By exhaustive searching using comprehensive experimental approaches, we show that proliferative GSCs and neo-meiocytes by these specific criteria were undetectable in adult mouse and monkey ovaries. However, we found proliferative nongermline somatic stem cells that do not express LAMIN A and germ cell markers in the adult ovaries, notably in the cortex and granulosa cells of growing follicles. These data support the paradigm that adult ovaries do not undergo germ cell renewal, which may contribute significantly to ovarian senescence that occurs with age.
Transplantation of human umbilical mesenchymal stem cells cures the corneal defects of mucopolysaccharidosis VII mice
Authors: Coulson-Thomas Vivien Jane , Caterson Bruce , Kao Winston W.-Y.
Published: July 2013

Mucopolysaccharidosis (MPS) are a family of related disorders caused by a mutation in one of the lysosomal exoglycosidases which leads to the accumulation of glycosaminoglycans (GAGs). MPS VII, caused by a mutation in β-glucuronidase, manifests hepatomegaly, skeletal dysplasia, short stature, corneal clouding, and developmental delay. Current treatment regimens for MPS are not effective for treating corneal clouding and impaired mental development. We hypothesized that human umbilical mesenchymal stem cells (UMSCs) transplanted into the corneal stroma could participate in the catabolism of GAGs providing a means of cell therapy for MPS. For such treatment, human UMSCs were intrastromally transplanted into corneas of MPS VII mice. UMSC transplantation restored the dendritic and hexagonal morphology of host keratocytes and endothelial cells, respectively, and in vivo confocal microscopy (HRT-II) revealed reduced corneal haze. Immunohistochemistry using antibodies against heparan sulfate and chondroitin sulfate chains as well as lysosomal-associated membrane protein 2 revealed a decrease in GAG content and both lysosomal number and size in the treated corneas. Labeling UMSC intracellular compartments prior to transplantation revealed the distribution of UMSC vesicles throughout the corneal stroma and endothelium. An in vitro coculture assay between skin fibroblasts isolated from MPS VII mice and UMSC demonstrated that neutral vesicles released by the UMSC are taken up by the fibroblasts and proceed to fuse with the acidic lysosomes. Therefore, transplanted UMSCs participate both in extracellular GAG turnover and enable host keratocytes to catabolize accumulated GAG products, suggesting that UMSC could be a novel alternative for treating corneal defects associated with MPS and other congenital metabolic disorders.
Lgr4 is a key regulator of prostate development and prostate stem cell differentiation
Authors: Luo Weijia , Rodriguez Melissa , Valdez Joseph M. , Zhu Xinglei , Tan Kunrong , Li Dali , Siwko Stefan , Xin Li , Liu Mingyao
Published: July 2013

echanisms modulating prostate cell fate determination remain unexplored. The leucine-rich repeat containing G-protein-coupled receptors (Lgr) have been identified as important stem cell markers in various tissues. Here, we investigated the roles of Lgr4/Gpr48 in prostate stem cells (PSCs) and development. Lgr4 was ubiquitously expressed during early prostate development prior to lineage specification, with adult expression restricted to a few basal cells (principally Lin−Sca1+CD49f+). Lgr4−/− mice had compromised branching morphogenesis and delayed epithelial differentiation, leading to decreased prostate size and impaired luminal cell function. In vitro prostate sphere culture revealed that Lgr4−/− Lin−/Sca1+/CD49f+ cells failed to generate p63low cells, indicating a differentiation deficiency. Furthermore, Lgr4 ablation arrested PSC differentiation of in vivo kidney capsule prostate grafts, suggesting that Lgr4 modulates PSC properties independent of hormonal and mesenchymal effects. Analysis of neonatal prostates and prostate spheres revealed a decrease in Wnt, Sonic Hedgehog, and Notch1 expression in Lgr4−/− cells. Lgr4 loss blocked differentiation of prostate sphere p63hi cells to p63low. Treatment with exogenous Sonic Hedgehog partially restored the differentiation of p63hi cells in Lgr4−/− spheres. Taken together, our data revealed the roles of Lgr4 in early prostate development and in stem cell differentiation through regulation of the Wnt, Notch, and Sonic Hedgehog signaling pathways.
Developmental and oncogenic radiation effects on neural stem cells and their differentiating progeny in mouse cerebellum
Authors: Tanori Mirella , Pasquali Emanuela , Leonardi Simona , Casciati Arianna , Giardullo Paola , Stefano Ilaria , Mancuso Mariateresa , Saran Anna , Pazzaglia Simonetta
Published: July 2013

Neural stem cells are highly susceptible to radiogenic DNA damage, however, little is known about their mechanisms of DNA damage response (DDR) and the long-term consequences of genotoxic exposure. Patched1 heterozygous mice (Ptc1+/−) provide a powerful model of medulloblastoma (MB), a frequent pediatric tumor of the cerebellum. Irradiation of newborn Ptc1+/− mice dramatically increases the frequency and shortens the latency of MB. In this model, we investigated the mechanisms through which multipotent neural progenitors (NSCs) and fate-restricted progenitor cells (PCs) of the cerebellum respond to DNA damage induced by radiation, and the long-term developmental and oncogenic consequences. These responses were assessed in mice exposed to low (0.25 Gy) or high (3 Gy) radiation doses at embryonic day 13.5 (E13.5), when NSCs giving rise to the cerebellum are specified but the external granule layer (EGL) has not yet formed, or at E16.5, during the expansion of granule PCs to form the EGL. We found crucial differences in DDR and apoptosis between NSCs and fate-restricted PCs, including lack of p21 expression in NSCs. NSCs also appear to be resistant to oncogenesis from low-dose radiation exposure but more vulnerable at higher doses. In addition, the pathway to DNA repair and the pattern of oncogenic alterations were strongly dependent on age at exposure, highlighting a differentiation-stage specificity of DNA repair pathways in NSCs and PCs. These findings shed light on the mechanisms used by NSCs and PCs to maintain genome integrity during neurogenesis and may have important implications for radiation risk assessment and for development of targeted therapies against brain tumors.
MEK/ERK signaling directly and indirectly contributes to the cyclical self-renewal of spermatogonial stem cells
Authors: Hasegawa Kazuteru , Namekawa Satoshi H. , Saga Yumiko
Published: July 2013

Coordination of stem cell fate is regulated by extrinsic niche signals and stem cell intrinsic factors. In mammalian testes, spermatogonial stem cells maintain constant production of abundant spermatozoa by alternating between self-renewal and differentiation at regular intervals according to a periodical program known as the seminiferous epithelial cycle. Although retinoic acid (RA) signaling has been suggested to direct the cyclical differentiation of spermatogonial stem cells, it remains largely unclear how their cycle-dependent self-renewal/proliferation is regulated. Here, we show that MEK/ERK signaling contributes to the cyclical activity of spermatogonial stem cells. We found that ERK1/2 is periodically activated in Sertoli cells during the stem cell self-renewal/proliferation phase, and that MEK/ERK signaling is required for the stage-related expression of the critical niche factor GDNF. In addition, ERK1/2 is activated in GFRα1-positive spermatogonial stem cells under the control of GDNF and prevent them from being differentiated. These results suggest that MEK/ERK signaling directly and indirectly maintains spermatogonial stem cells by mediating a signal that promotes their periodical self-renewal/proliferation. Conversely, RA signaling directly and indirectly induces differentiation of spermatogonial stem cells. We propose that temporally regulated activations of RA signaling and a signal regulating MEK/ERK antagonistically coordinates the cycle-related activity of spermatogonial stem cells.
Additional value of prenatal genomic array testing in fetuses with isolated structural ultrasound abnormalities and a normal karyotype: a systematic review of the literature
Authors: de wit M. C. , Srebniak M. I. , Govaerts L. C. P. , Van Opstal D. , Galjaard R. J. H. , Go A. T. J. I.
Published: July 2013

OBJECTIVE

To establish the prevalence of submicroscopic genetic copy number variants (CNVs) in fetuses with a structural ultrasound anomaly (restricted to one anatomical system) and a normal karyotype. The aim was to determine the diagnostic and prognostic value of genomic array testing in these pregnancies.

Methods

Embase and PubMed databases were systematically searched for all relevant articles on prevalence of pathogenic submicroscopic CNVs in fetuses with ultrasound anomalies. Reported cases were sorted into groups according to anatomical site of the detected ultrasound anomaly. The prevalence of causative submicroscopic CNVs was calculated for each group.

Results

Combined data of the reviewed studies (n = 18) indicated that fetuses with an ultrasound anomaly restricted to one anatomical system (n = 2220) had a 3.1–7.9% chance of carrying a causative submicroscopic CNV, depending on the anatomical system affected. This chance increased to 9.1% for fetuses with multiple ultrasound anomalies (n = 1139).

Conclusion

This review indicates that 3.1–7.9% of fetuses with a structural ultrasound anomaly restricted to one anatomical system and a normal karyotype will show a submicroscopic CNV, which explains its phenotype and provides information for fetal prognosis. Therefore, we conclude that microarray has considerable diagnostic and prognostic value in these pregnancies. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Stress intensity factor for an infinite plane containing three collinear cracks under compression
Authors: Zheng T. , Zhu Z. , Wang B. , Zeng L.
Published: July 2013

The fracture behaviour of multi‐cracked materials has become a key issue in fracture mechanics and has received large attention recently. In this paper, an infinite plane containing three collinear cracks under biaxial compression has been investigated. Considering crack surface friction and using complex stress function theory, the exact analytical solution of stress intensity factors (SIFs) for an infinite plane containing three collinear cracks is obtained. The corresponding finite element code of Abaqus is employed to validate the theoretical results, and its results agree very well with the theoretical results. The effects of confining stresses, crack distances and the crack surface frictions on SIFs are analyzed through the theoretical results and the Abaqus code. A photoelastic experiment was conducted to validate the theoretical result about the effect of confining stresses.
Strong solutions to the Navier–Stokes–Fourier system with slip–inflow boundary conditions
Authors: Piasecki T. , Pokorný M.
Published: July 2013

We consider a system of partial differential equations describing the steady flow of a compressible heat conducting Newtonian fluid in a three‐dimensional channel with inflow and outflow part. We show the existence of a strong solution provided the data are close to a constant, but nontrivial flow with sufficiently large dissipation in the energy equation.
The demography of native and non‐native plant species in mountain systems: examples in the Greater Yellowstone Ecosystem
Authors: Pollnac Fredric W. , Maxwell Bruce D. , Taper Mark L. , Rew Lisa J.
Published: July 2013

In mountainous areas, native and non‐native plants will be exposed to climate change and increased disturbance in the future. Non‐native plants may be more successful than natives in disturbed areas and thus be able to respond quicker to shifting climatic zones. In 2009, monitoring plots were established for populations of a non‐native species (Linaria dalmatica) and a closely related native species (Castilleja miniata) on an elevation gradient in the Greater Yellowstone Ecosystem, USA. Population data were collected twice during the growing season for 3 years and used to calculate population vital rates for both species, and to construct population dynamics models forL. dalmatica.Linaria dalmaticavital rates were more associated with climatic/environmental factors than those ofC. miniata. Population dynamics models forL. dalmaticashowed no trend in population growth rate (λ) vs. elevation. The highestλcorresponded with the lowest vegetation and litter cover, and the highest bare ground cover. All populations withλ< 1 corresponded with the lowest measured winter minimum temperature. There was a negative association betweenλand number of weeks of adequate soil moisture, and a weak positive association betweenλand mean winter minimum temperature. Variance in vital rates andλofL. dalmaticasuggest broad adaptation within its current range, with the potential to spread further with or without future changes in climate. There is evidence thatλis negatively affected by persistent soil moisture which promotes the growth of other plant species, suggesting that it might expand further if other species were removed by disturbance.
Structural and biochemical characterization of Rv2140c, a phosphatidylethanolamine‐binding protein from Mycobacterium tuberculosis
Authors: Eulenburg Georg , Higman Victoria A. , Diehl Anne , Wilmanns Matthias , Holton Simon J.
Published: July 2013

Rv2140c is one of many conserved Mycobacterium tuberculosis proteins for which no molecular function has been identified. We have determined a high‐resolution crystal structure of the Rv2140c gene product, which reveals a dimeric complex that shares strong structural homology with the phosphatidylethanolamine‐binding family of proteins. Rv2140c forms low‐millimolar interactions with a selection of soluble phosphatidylethanolamine analogs, indicating that it has a role in lipid metabolism. Furthermore, the small molecule locostatin binds to the Rv2140c ligand‐binding site and also inhibits the growth of the model organism Mycobacterium smegmatis.
ATAF1 transcription factor directly regulates abscisic acid biosynthetic gene NCED3 in Arabidopsis thaliana
Authors: Jensen Michael Krogh , Lindemose Søren , de Masi Federico , Reimer Julia J. , Nielsen Michael , Perera Venura , Workman Chris T. , Turck Franziska , Grant Murray R. , Mundy John , Petersen Morten , Skriver Karen
Published: July 2013

ATAF1, an Arabidopsis thaliana NAC transcription factor, plays important roles in plant adaptation to environmental stress and development. To search for ATAF1 target genes, we used protein binding microarrays and chromatin‐immunoprecipitation (ChIP). This identified T[A,C,G]CGT[A,G] and TT[A,C,G]CGT as ATAF1 consensus binding sequences. Co‐expression analysis across publicly available microarray experiments identified 25 genes co‐expressed with ATAF1. The promoter regions of ATAF1 co‐expressors were significantly enriched for ATAF1 binding sites, and TTGCGTA was identified in the promoter of the key abscisic acid (ABA) phytohormone biosynthetic gene NCED3. ChIP‐qPCR and expression analysis showed that ATAF1 binding to the NCED3 promoter correlated with increased NCED3 expression and ABA hormone levels. These results indicate that ATAF1 regulates ABA biosynthesis.
Comparison of non-linear models to describe the lactation curves of milk yield and composition in Iranian Holsteins
Authors: HOSSEIN-ZADEH N. GHAVI
Published: July 2013

In order to describe the lactation curves of milk yield (MY) and composition, six non-linear mathematical equations (Wood, Dhanoa, Sikka, Nelder, Hayashi and Dijkstra) were used. Data were 5 535 995 test-day records for MY, fat (FC) and protein (PC) contents and somatic cell score (SCS) from the first three lactations of Iranian Holstein cows that were collected on 2547 dairy herds in the period from 2000 to 2011 by the Animal Breeding Center of Iran. Each model was fitted to monthly production records of dairy cows using the NLIN and MODEL procedures in SAS and the parameters were estimated. The models were tested for goodness of fit using root-mean-square error (RMSE), Durbin–Watson statistic (DW) and Akaike's information criterion (AIC). The Wood and Dhanoa models provided the best fit of the lactation curve for MY in the first and second parities due to the lower values of RMSE and AIC than other models; but the Dijkstra model showed the best fit of milk lactation curve for third-parity dairy cows, FC, PC and SCS in the first three parities because of the lowest values of RMSE and AIC. Also, In general, the Sikka model did not fit the production data as well as the other equations. The results showed that the Dijkstra equation was able to estimate the time to the peak and peak MY more accurately than the other equations. However, the Wood equation provided more accurate predictions of peak MY at second- and third parities than the other equations. For first lactation FC, the Dijkstra equation was able to estimate the minimum FC and for second- and third-parity FC, the Wood equation provided more accurate predictions of minimum FC. For first- and second-lactation PC, the Dijkstra equation was able to estimate the minimum PC but for third parity, the minimum value of PC was predicted more accurately by the Wood model. The Dhanoa and Dijkstra equations for first lactation SCS and the Dhanoa equation for second- and third- lactation SCS were able to estimate the minimum SCS more accurately than the other equations. Overall, evaluation of different equations used in the current study indicated the potential of the non-linear functions for fitting monthly productive records of Holstein cows.
Abundance and density estimates for common leopard Panthera pardus and clouded leopard Neofelis nebulosa in Manas National Park, Assam, India
Authors: Borah Jimmy , Sharma Tridip , Das Dhritiman , Rabha Nilmani , Kakati Niraj , Basumatary Ajit , Ahmed M. Firoz , Vattakaven Joseph
Published: July 2013

Effective conservation of rare carnivores requires reliable estimates of population density for prioritizing investments and assessing the effectiveness of conservation interventions. We used camera traps and capture–recapture analysis to provide the first reliable abundance and density estimates for the common leopard Panthera pardus and clouded leopard Neofelis nebulosa in Manas National Park, India. In 57 days of camera trapping, with a total of 4,275 camera-trap days, we photo-captured 27 individually identified common leopards (11 males, 13 females and three unidentified), and 16 clouded leopards (four males, five females and seven unidentified). The abundance estimates using the Mh jackknife and Pledger model Mh were 47.0 and 35.6, respectively, for the common leopard, and 21.0 and 25.0, respectively, for the clouded leopard. Density estimates using maximum likelihood spatially-explicit capture–recapture were 3.4 ± SE 0.82 and 4.73 ± SE 1.43 per 100 km2 for the common and clouded leopards, respectively. Spatially-explicit capture–recapture provided more realistic density estimates compared with those obtained from conventional methods. Our data indicates that camera trapping using a capture–recapture framework is an effective tool for assessing population sizes of cryptic and elusive carnivores such as the common and clouded leopards. The study has established a baseline for the long-term monitoring programme for large carnivores in Manas National Park.