bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of α‐Hydroxyallenes by Copper‐Catalyzed SN2′ Substitution of Propargylic Dioxolanones
Authors: Tang Xiaoping , Woodward Simon , Krause Norbert 
Published: April 2009

AbstractA new catalytic method for the synthesis of α‐hydroxyallenes is described. Efficient SN2′ substitution of propargylic dioxolanones has been achieved with a copper(I)/P(OBu)3 catalyst using Grignard reagents as the nucleophiles. The reaction tolerates a wide variety of propargylic dioxolanones, the corresponding primary and secondary α‐hydroxyallenes are obtained in good to excellent yields and excellent diastereoselectivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
The effects of interdune vegetation changes on eolian dune field evolution: a numerical‐modeling case study at Jockey's Ridge, North Carolina, USA
Authors: Pelletier Jon D. , Mitasova Helena , Harmon Russell S. , Overton Margery 
Published: April 2009

AbstractChanges in vegetation cover within dune fields can play a major role in how dune fields evolve. To better understand the linkage between dune field evolution and interdune vegetation changes, we modified Werner's (Geology, 23, 1995: 1107–1110) dune field evolution model to account for the stabilizing effects of vegetation. Model results indicate that changes in the density of interdune vegetation strongly influence subsequent trends in the height and area of eolian dunes. We applied the model to interpreting the recent evolution of Jockey's Ridge, North Carolina, where repeat LiDAR surveys and historical aerial photographs and maps provide an unusually detailed record of recent dune field evolution. In the absence of interdune vegetation, the model predicts that dunes at Jockey's Ridge evolve towards taller, more closely‐spaced, barchanoid dunes, with smaller dunes generally migrating faster than larger dunes. Conversely, the establishment of interdune vegetation causes dunes to evolve towards shorter, more widely‐spaced, parabolic forms. These results provide a basis for understanding the increase in dune height at Jockey's Ridge during the early part of the twentieth century, when interdune vegetation was sparse, followed by the decrease in dune height and establishment of parabolic forms from 1953‐present when interdune vegetation density increased. These results provide a conceptual model that may be applicable at other sites with increasing interdune vegetation cover, and they illustrate the power of using numerical modeling to model decadal variations in eolian dune field evolution. We also describe model results designed to test the relative efficacy of alternative strategies for mitigating dune migration and deflation. Installing sand‐trapping fences and/or promoting vegetation growth on the stoss sides of dunes are found to be the most effective strategies for limiting dune advance, but these strategies must be weighed against the desire of many park visitors to maintain the natural state of the dunes. Copyright © 2009 John Wiley & Sons, Ltd.
Modulation of α‐crystallin chaperone activity: A target to prevent or delay cataract?
Authors: Kumar Pasupulati Anil , Reddy Geereddy Bhanuprakash 
Published: April 2009

AbstractCataract, loss of eye lens transparency, is the leading cause of blindness worldwide. α‐Crystallin, initially known as one of the major structural proteins of the eye lens, is composed of two homologous subunits αA‐ and αB‐crystallins. It is convincingly established now that α‐crystallin functions like a chaperone and plays a decisive role in the maintenance of eye lens transparency. The functional ability of α‐crystallin subunits is to act in cooperation as molecular chaperones to prevent the cellular aggregation and/or inactivation of client proteins under variety of stress conditions. However, chaperone‐like activity of α‐crystallin could be deteriorated or lost during aging or under certain clinical conditions because of various genetic and environmental factors. This review will focus specifically on relevance of α‐crystallin chaperone function to lens transparency. In particular, we reviewed the studies that demonstrate the modulation of α‐crystallin chaperone‐like activity and discussed the possibility of chaperone‐like activity of α‐crystallin as a potential target to prevent or delay the cataractogenesis. © 2009 IUBMB IUBMB Life, 61(5): 485–495, 2009
Novel oncogenic actions of TRβ mutants in tumorigenesis
Authors: Guigon Celine J. , Cheng Sheue‐yann 
Published: April 2009

AbstractThe thyroid hormone, T3, plays important roles in metabolism, growth, and differentiation. Germline mutations in thyroid hormone receptor beta (TRβ) have been identified in many individuals with resistance to thyroid hormone, a syndrome of reduced sensitivity to T3. A close association of somatic mutations of TRβ with several human cancers has become increasingly apparent, but how TRβ mutants could be involved in the carcinogenesis in vivo has not been addressed. The creation of a mouse model (TRβPV/PV mouse) that harbors a knockin mutation of TRβ (denoted TRβPV) has facilitated the study of the molecular actions of TRβ mutants in vivo. The striking phenotype of thyroid cancer and the development of pituitary tumors exhibited by TRβPV/PV mice have uncovered novel functions of a TRβ mutant in tumorigenesis. It led to the important findings that the oncogenic action of TRβPV is mediated by both genomic and nongenomic actions to alter gene expression and signaling pathways activity. © 2009 IUBMB IUBMB Life, 61(5): 528–536, 2009
Retinal deimination in aging and disease
Authors: Bhattacharya Sanjoy K. 
Published: April 2009

AbstractDeimination is a posttranslational modification and refers to the conversion of protein bound arginine into citrulline. In the retina, deimination is predominantly catalyzed by Peptidylarginine deiminase type 2 (PAD2). PAD2 expression and deimination are found in many different retinal layers: choroid, retinal pigment epithelium (RPE), photoreceptors, inner plexiform layer, inner nuclear layer, and retinal ganglion cell (RGC) layer. Although decreased retinal deimination and PAD2 expression have been found during normal aging, elevated PAD2 expression and deimination have been observed in age‐related neurodegenerative diseases. The role of deimination in normal physiology and in late‐onset and progressive ocular or retinal degenerative diseases, such as glaucoma and experimental autoimmune encephalomyelitis remains to be elucidated. © 2009 IUBMB IUBMB Life, 61(5): 504–509, 2009
GABA increases Ca2+ in cerebellar granule cell precursors via depolarization: Implications for proliferation
Authors: Dave Kathleen A. , Bordey Angélique 
Published: April 2009

AbstractThe amino acids glutamate and gamma‐aminobutyric acid (GABA) have primarily been characterized as the most prevalent excitatory and inhibitory, respectively, neurotransmitters in the vertebrate central nervous system. However, the role of these signaling molecules extends far beyond the synapse. GABA, glutamate, and their complement of receptors are essential signaling molecules that regulate developmental processes in both embryonic and young adult mammals. In this review, we describe the current knowledge on the role of GABA and glutamate in development, focusing on the perinatal cerebellum. We will then present novel data suggesting that GABA depolarizes granule cell precursors via GABAA receptors, which leads to calcium increases in these cells. Finally, we will consider the role of GABA and glutamate signaling on cell proliferation and perhaps neural cancers. From our review of the literature and these data, we hypothesize that GABAA receptors and metabotropic glutamate receptors may be a novel target for the pharmacological regulation of the cerebellar tumors, medulloblastomas. © 2009 IUBMB IUBMB Life, 61(5): 496–503, 2009
GSK‐3: A key player in neurodegeneration and memory
Authors: Giese Karl Peter 
Published: April 2009

AbstractAbnormalities in molecular signalling have been implicated in neurodegeneration. It is emerging that glycogen synthase kinase‐3 (GSK‐3) is a key signalling molecule that induces neurodegeneration and deficits in memory formation related to Alzheimer's disease (AD). Early stages of AD are associated with deficits in memory formation before neuronal cell death is detectable. Recent studies in rodents have suggested that these impairments in memory formation might result from increased GSK‐3 signalling, because enhanced GSK‐3 activity impairs hippocampal memory formation. GSK‐3 activity blocks synaptic long‐term potentiation and induces long‐term depression. Furthermore, increased GSK‐3 signalling is likely to be a key contributor to the formation of the pathological hallmarks in AD, neurofibrillary tangles (NFTs) and amyloid plaques. Recent studies with mouse models have indicated that GSK‐3, but not cyclin‐dependent kinase 5, is critical for hyperphosphorylation of the cytoskeletal protein tau, which is the prerequisite for NFT formation in AD. Furthermore, increased GSK‐3 signalling in AD mice causes abnormal processing of the amyloid precursor protein so that amyloid peptide production augments and neurotoxicity is induced. Taken together, the current evidences suggest that increased GSK‐3 signalling may be responsible for the deficits in memory formation in early stages of AD and neurodegeneration in later stages of the disease. © 2009 IUBMB IUBMB Life 61(5): 516–521, 2009
Oxidized proteins: Mechanisms of removal and consequences of accumulation
Authors: Dunlop Rachael A. , Brunk Ulf T. , Rodgers Kenneth J. 
Published: April 2009

AbstractElevated levels of oxidized proteins are reported in diseased tissue from age‐related pathologies such as atherosclerosis, neurodegenerative disorders, and cataract. Unlike the precise mechanisms that exist for the repair of nucleic acids, lipids, and carbohydrates, the primary pathway for the repair of oxidized proteins is complete catabolism to their constitutive amino acids. This process can be inefficient as is evidenced by their accumulation. It is generally considered that damaged proteins are degraded by the proteasome; however, this is only true for mildly oxidized proteins, because substrates must be unfolded to enter the narrow catalytic core. Rather, evidence suggests that moderately or heavily oxidized proteins are endocytosed and enter the endosomal/lysosomal system, indicating co‐operation between the proteasomes and the lysosomes. Heavily modified substrates are incompletely degraded and accumulate within the lysosomal compartments resulting in the formation of lipofuscin‐like, autofluorescent aggregates. Accumulation eventually results in impaired turnover of large organelles such as proteasomes and mitochondria, lysosomal destablization, leakage of proteases into the cytosol and apoptosis. In this review, we summarize reports published since our last assessments of the field of oxidized protein degradation including a role for modified proteins in the induction of apoptosis. © 2009 IUBMB IUBMB Life, 61(5): 522–527, 2009
Exploring enantioselective molecular recognition mechanisms with chemoinformatic techniques
Authors: Del Rio Alberto 
Published: April 2009

AbstractA comprehensive review of chemoinformatic techniques and studies applied to the field of enantioselective molecular recognition is presented. Several approaches such as enantiophores/pharmacophore modelling, QSPRs, CoMFA and other insightful data mining procedures are discussed. The review focuses on the central role of chemoinformatic approaches on the establishment of connections between available experimental data, mainly HPLC separation data, and these algorithms that describe properties of chiral molecules. The general overview of the aforementioned calculations account for a use of these techniques as a valuable strategy to achieve reliable prediction systems, infer the mechanisms of chiral recognition, generate insight for the conception of new chiral receptors and corroborate and assist experimental techniques such as chiral LC. Moreover, it is pointed out that computer methods in this field promise a wide range of applications for both academia and industry, ranging from enantioselective reactions, drug discovery and analysis of high‐throughput screenings, to analytical and semi‐preparative separations or large‐scale production of enantiopure compounds.
Comparative proteomic and regulatory network analyses of the elongating pig conceptus
Authors: Degrelle Séverine A. , Blomberg Le Ann , Garrett Wesley M. , Li Robert W. , Talbot Neil C. 
Published: April 2009

AbstractEmbryo loss during peri‐implantation can approach 20% in swine following artificial insemination or natural mating and coincides with rapid conceptus elongation. The objective of the present study was to establish a comprehensive profile of the abundant proteins of the pig conceptus at the time prior to implantation and identify stage‐specific changes during elongation. The abundant proteins of a homogenous population of gestational day‐11 ovoid (0.7–1 cm) and gestational day‐12 filamentous (15–20 cm) porcine concepti were compared by extracting proteins from three independent conceptus pools and separating the proteins by 2‐DE. Proteins in 305 spots were analyzed by MALDI‐TOF or additionally by LC‐MS/MS and 275 were positively identified representing 174 distinct proteins. The proteins could be classified into the following functional categories: cell proliferation/differentiation, cytoskeleton, metabolism, and stress response. Based on spot density, 35 proteins associated with cell proliferation, differentiation, apoptosis, and embryo/maternal signaling, were found to be differentially expressed between ovoid and filamentous concepti. A comparison of the protein expression profile with transcriptomic data from pig concepti of the same developmental stages identified similarities and dissimilarities between protein and mRNA expression profiles. This proteomic study helps to elucidate the biological mechanisms underlying the early embryonic development of the pig.
High efficiency solid state laser cooling in Yb3+:ZBLANP fiber with tilted fiber Bragg grating structures
Authors: Nemova Galina , Kashyap Raman 
Published: April 2009

AbstractAn optimized fiber structure for use in anti‐Stokes laser cooling of solids is presented. The sample is an optical fiber fabricated from a fluorozirconate glass ZBLANP (ZrF4‐BaF2‐LaF3‐AlF3‐NaF‐PbF2) with a core doped with Yb3+ ions and optimized to achieve the largest temperature change in the sample starting at room temperature.It is shown that the change in the temperature of the sample is a function of the geometry of the fiber. For each pump power there is an optimized diameter of the fiber core, for which the largest drop occurs in the temperature of the sample. A titled Bragg grating imprinted into the fiber core is suggested to prevent the re‐absorption of anti‐Stokes photons. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependence of carrier traps in high sensitivity HARP photoconductive film
Authors: Ohkawa Yuji , Miyakawa Kazunori , Matsubara Tomoki , Kikuchi Kenji , Suzuki Shirou , Kubota Misao , Egami Norifumi , Kobayashi Akira 
Published: April 2009

AbstractAmorphous selenium (a‐Se) avalanche multiplication photoconductive film, what we call HARP (high‐gain avalanche rushing amorphous photoconductor) photoconductive film, has been investigated for the purpose of reporting breaking news at night and producing nature and science programs. The purpose of our work is to develop more sensitive HARP films with high reliability. 15‐μm‐thick HARP film with an avalanche multiplication factor of about 200 that is thicker and more sensitive than the previous 8‐μm‐thick one has been studied. However, the thick film has a problem that defects easily occurred during shooting of intense spot lights. The defects are caused by trapped electrons which makes an enhanced internal electric field around the incident light side interface of the film. Defects are suppressed by operating the film at high temperatures, because the thermal energy releases the trapped electrons. This paper describes the relationship between the defect occurrence and the temperature dependence of carries trap in the film. To investigate it, the defect occurrence and dark current characteristics were measured. As a result, it was found that the number of released electrons exceeds that of trapped ones at temperatures over 28.5 °C and that defect occurrence is suppressed by operating the film at over 27.5 °C. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Noise analysis of a novel hybrid active‐passive pixel sensor for medical X‐ray imaging
Authors: Safavian N. , Izadi M. H. , Sultana A. , Wu D. , Karim K. S. , Nathan A. , Rowlands J. A. 
Published: April 2009

AbstractPassive pixel sensor (PPS) is one of the most widely used architectures in large area amorphous silicon (a‐Si) flat panel imagers. It consists of a detector and a thin film transistor (TFT) acting as a readout switch. While the PPS is advantageous in terms of providing a simple and small architecture suitable for high‐resolution imaging, it directly exposes the signal to the noise of data line and external readout electronics, causing significant increase in the minimum readable sensor input signal. In this work we present the operation and noise performance of a hybrid 3‐TFT current programmed, current output active pixel sensor (APS) suitable for real‐time X‐ray imaging. The pixel circuit extends the application of a‐Si TFT from conventional switching element to on‐pixel amplifier for enhanced signal‐to‐noise ratio and higher imager dynamic range. The capability of operation in both passive and active modes as well as being able to compensate for inherent instabilities of the TFTs makes the architecture a good candidate for X‐ray imaging modalities with a wide range of incoming X‐ray intensities. Measurement and theoretical calculations reveal a value for input refferd noise below the 1000 electron noise limit for real‐time fluoroscopy. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time evolution of absorption process in nonlinear metallic photonic crystals
Authors: Singh Mahi R. , Hatef Ali 
Published: April 2009

AbstractThe time evolution of the absorption coefficient in metallic photonic crystals has been studied numerically. These crystals are made from metallic spheres which are arranged periodically in air. The refractive index of the metallic spheres depends on the plasma frequency. Probe and pump fields are applied to monitor the absorption process. Ensembles of three‐level particles are embedded in the crystal. Nanoparticles are interactiing with the metallic crystals via the electron‐photon interaction. It is found that when the resonance states lie away from the band edges system goes to transparent sate. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ag‐photodoping in nano‐structured GeO2‐GeS2 glasses
Authors: Terakado Nobuaki , Tanaka Keiji 
Published: April 2009

AbstractComposition dependence of Ag‐photodoping in x GeO2‐(100–x)GeS2 glasses has been studied. The doping rate decreases with an increase in x, and becomes negligible at x ≥ 60. This photodoping disappearance can be related with transformation from percolated GeS2 networks in the heterogeneous oxy‐chalcogenide glasses to isolated nano‐scale clusters. Remarks on photodoping processes and overall composition dependences are also given. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Near‐field modulation of AlGaInP laser diode emissions by an aperture probe of near‐field optical microscope
Authors: Kamiyama Yasushi , Tomioka Akihiro , Anzai Takahiro , Iwamoto Kazuhisa , Susaki Wataru 
Published: April 2009

AbstractIn situ emission profiles of AlGaInP multiple quantum well laser diodes (LD's) observed by a near‐field scanning optical microscope (NSOM) aperture probe shows a single broad elliptic profile similar to a far‐field observation, whereas the local emission spectrum was different depending where the aperture probe was positioned within the emission profile. This observation suggests the existence of a near‐field coupling between the aperture and the LD cavity, which modulates the lasing wavelength among the longitudinal multimodes determined by the LD cavity length. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radiation‐induced optically stimulated luminescence in Mn2+ and Eu2+ doped RbMgF3
Authors: Williams G. V. M. , Dotzler C. , Robinson J. 
Published: April 2009

AbstractRadiation‐induced optically stimulated luminescence is observed in RbMgF3 when doped with Mn2+ or Eu2+. This compound can be used for radiation dosimetry where the dose information can be optically read and reset. The main difference between RbMgF3:Mn2+ and RbMgF3:Eu2+ is due to the fact that RbMgF3:Mn2+ has deep traps when compared with RbMgF3:Eu2+ that are evident as high temperature peaks in the thermoluminescence data. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A multistate approach for estimating the incidence of human immunodeficiency virus by using HIV and AIDS French surveillance data
Authors: Sommen Cécile , Alioum Ahmadou , Commenges Daniel 
Published: April 2009

AbstractBefore the introduction of highly active antiretroviral therapy (HAART) in 1996, monitoring the epidemics of HIV infection was extensively based on back‐calculating the number of new HIV infections from AIDS surveillance data and knowledge of the AIDS incubation period distribution. However, the increase in the AIDS incubation period induced by HAART has complicated the use of AIDS diagnosis data only, and made it necessary to supplement these data with HIV diagnosis data. We explore the advantage of combining HIV and AIDS surveillance data in the context where the HIV diagnosis data are available only for the most recent years. Extending the earlier work of Aalenet al. (Statist. Med.1997;16(19):2191–2210) based on a discrete‐time Markov model that describes simultaneously disease progression, HIV diagnosis and treatment intake, we propose a penalized likelihood approach to estimate smooth HIV incidence, together with HIV diagnosis rates. The smoothing parameter is chosen using an approximated cross‐validation criterion. In a simulation study, we show that incorporation of HIV test information improves the precision of the estimation of the incidence of infections in recent periods. The method is illustrated using HIV and AIDS surveillance data collected by the Institut de Veille Sanitaire, France. Copyright © 2009 John Wiley & Sons, Ltd.