bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upregulation of the Mammalian Target of Rapamycin Complex 1 Pathway by Ras Homolog Enriched in Brain in Pancreatic β-Cells Leads to Increased β-Cell Mass and Prevention of Hyperglycemia
Authors: Hamada Suirin , Hara Kenta , Hamada Takeshi , Yasuda Hisafumi , Moriyama Hiroaki , Nakayama Rika , Nagata Masao , Yokono Koichi 
Published: March 2009

OBJECTIVE
Components of insulin/IGF-1 receptor–mediated signaling pathways in pancreatic β-cells have been implicated in the development of diabetes, in part through the regulation of β-cell mass in vivo. Studies in vitro have shown that the protein Ras homolog enriched in brain (Rheb) plays a key role as a positive upstream regulator of the mammalian target of rapamycin complex 1 (mTORC1) pathway in integrating inputs from nutrients and growth factors for cell growth. Our objective was to investigate the role of the mTORC1 pathway in the regulation of β-cell mass in vivo.

RESEARCH DESIGN AND METHODS
We generated transgenic mice that overexpress Rheb in β-cells. We examined the activation of the mTORC1 pathway and its effects on β-cell mass, on glucose metabolism, and on protection against hyperglycemia.

RESULTS
Immunoblots of islet extracts revealed that the phosphorylation levels of ribosomal protein S6 and eukaryotic initiation factor 4E binding protein 1, downstream effectors for mTORC1, were upregulated in transgenic β-cells. Immunostaining of the pancreatic sections with anti–phospho-S6 antibody confirmed upregulation of the mTORC1 pathway in β-cells in vivo. The mice showed improved glucose tolerance with higher insulin secretion. This arose from increased β-cell mass accompanied by increased cell size. The mice also exhibited resistance to hyperglycemia induced by streptozotocin and obesity.

CONCLUSIONS
Activation of the mTORC1 pathway by Rheb led to increased β-cell mass in this mouse model without producing obvious unfavorable effects, giving a potential approach for the treatment of β-cell failure and diabetes.
Dislocations as Active Components in Novel Silicon Devices
Authors: Kittler Martin , Reiche Manfred 
Published: March 2009

AbstractThe electrical and optical properties of dislocations in Si are reviewed, namely dislocation‐related recombination and luminescence, transport of minority and majority carriers along dislocations or the electric field around dislocations. It is shown that Si wafer direct bonding allows well‐controlled formation of dislocation networks, giving rise to adjustable dislocation properties. Ideas for novel Si devices utilizing dislocations as active components are presented. In particular, dislocation‐based light emitters at about 1.5 µm wavelength are demonstrated. Concepts for dislocation‐based conductive channels and fast FETs, manipulators of biomolecules or thermo‐electric generators are sketched.
Analysis of Improved Efficiency of InGaN Light‐Emitting Diode With Bottom Photonic Crystal Fabricated by Anodized Aluminum Oxidxe
Authors: Ryu Sang‐Wan , Park Joonmo , Oh Jin‐Kyoung , Long Dang Hoang , Kwon Kwang‐Woo , Kim Young‐Ho , Lee Jun Key , Kim Jin Hyeok 
Published: March 2009

AbstractThe improved performance of a bottom photonic crystal (PC) light‐emitting diode (LED) is analyzed based on internal quantum efficiency (ηint) and light‐extraction efficiency (ηex). The bottom PC is fabricated by anodized aluminum oxide nanopatterns and InGaN quantum wells (QWs) are grown over it. Transmission electron microscopy images reveal that threading dislocations are blocked at the nanometer‐sized air holes, resulting in improved optical emission efficiency of the QWs. From temperature‐dependent photoluminescence measurements, the enhancement of ηint is estimated to be 12%. Moreover, the enhancement of ηex is simulated to be 7% by the finite‐difference time‐domain method. The fabricated bottom PC LED shows a 23% higher optical power than a reference, which is close to the summation of enhancements in ηint and ηex. Therefore, the bottom PC improves LED performance through higher optical quality of QWs as well as increased light extraction.
Inorganic Nanoparticles for MRI Contrast Agents
Authors: Na Hyon Bin , Song In Chan , Hyeon Taeghwan 
Published: March 2009

AbstractVarious inorganic nanoparticles have been used as magnetic resonance imaging (MRI) contrast agents due to their unique properties, such as large surface area and efficient contrasting effect. Since the first use of superparamagnetic iron oxide (SPIO) as a liver contrast agent, nanoparticulate MRI contrast agents have attracted a lot of attention. Magnetic iron oxide nanoparticles have been extensively used as MRI contrast agents due to their ability to shorten T2* relaxation times in the liver, spleen, and bone marrow. More recently, uniform ferrite nanoparticles with high crystallinity have been successfully employed as new T2 MRI contrast agents with improved relaxation properties. Iron oxide nanoparticles functionalized with targeting agents have been used for targeted imaging via the site‐specific accumulation of nanoparticles at the targets of interest. Recently, extensive research has been conducted to develop nanoparticle‐based T1 contrast agents to overcome the drawbacks of iron oxide nanoparticle‐based negative T2 contrast agents. In this report, we summarize the recent progress in inorganic nanoparticle‐based MRI contrast agents.
Laccase from Basidiomycetous Fungus Catalyzes the Synthesis of Substituted 5‐Deaza‐10‐oxaflavins via a Domino Reaction
Authors: Kidwai Mazaahir , Poddar Roona , Diwaniyan Sarika , Kuhad Ramesh Chander 
Published: March 2009

Abstractmagnified imageThe present investigation provides a simple and convenient route for the synthesis of substituted 5‐deaza‐10‐oxaflavins owing to their importance as probable redox coenzymes. The reaction of α,β‐unsaturated derivatives of barbituric acid and dimedone with catechol or 1,4‐hydroquinones was catalyzed using laccase in aqueous medium. Quinones, generated in situ by the oxidation of the corresponding catechol or 1,4‐hydroquinones, underwent a domino reaction with chalcones to produce 5‐deaza‐10‐oxaflavins and tetrahydroxanthen‐1‐ones.
Immobilisation of the BINAP Ligand on Dendrimers and Hyperbranched Polymers: Dependence of the Catalytic Properties on the Linker Unit
Authors: Kassube Jutta K. , Wadepohl Hubert , Gade Lutz H. 
Published: March 2009

Abstractmagnified imageA series of immobilised Carbo‐BINAP ligands has been synthesised using poly(propylene imine) (PPI) dendrimers as soluble supports. They contain up to 64 BINAP ligands at their periphery without an additional linking unit. Despite the high steric requirements of the ligand, all dendrimers could be completely functionalised, resulting in the immobilised systems in good yields. Furthermore, the immobilisation strategy that worked out for the fixation of AMINAP ligands with additional linking units as well as of Carbo‐BINAP ligands without additional linking units on dendrimers has thus been extended to less regularly hyperbranched poly(ethylene imines) (PEI) as soluble supports. In that way it has been possible to attach on average 9, 26, and 138 Glutaroyl‐AMINAP or Carbo‐BINAP ligands to PEIs of different molecular weights. The catalytic properties of these systems in the copper‐catalysed hydrosilylation of acetophenone were investigated. The dendritic PPI‐bound Carbo‐BINAP ligands displayed a strong dependence of enantioselectivity and activity on the generation of the dendrimer. For the Carbo‐BINAP and Glutaroyl‐AMINAP ligands immobilised on the hyperbranched polymers, however, activities and enantioselectivities comparable to those of the mononuclear catalysts were found. The macromolecular, immobilised BINAP ligands could be recycled several times without any observable loss of activity or enantioselectivity.
Highly Enantioselective Biphasic Iminium‐Catalyzed Epoxidation of Alkenes. On the Importance of the Counterion and of N(sp2)C(sp3) Rotamers
Authors: Novikov Roman , Bernardinelli Gérald , Lacour Jérôme 
Published: March 2009

Abstractmagnified imageDiastereomeric biaryliminium cations made of an (Ra)‐5,5′,6,6′,7,7′,8,8′‐octahydrobinaphthyl core and exocyclic appendages derived from (S)‐ or (R)‐3,3‐dimethylbutan‐2‐amine are effective asymmetric epoxidation catalysts for unfunctionalized alkenes. Herein, we report that the negative counterion of the iminium salts has to be chosen wisely. While the hexafluoroantimonate anion [SbF6−] is optimal for reliable results, one has to be careful about other anions and tetraphenylborate [BPh4−] in particular. We also detail that the so far unexplained “lack” of stereochemical control from the chiral exocyclic appendage in this type of catalysts is due to the existence of atropisomers around the N(sp2)C(sp3) bond that links the azepinium core to the exocyclic stereocenter. Finally, we develop a general model to predict with certainty the high selectivity in the formation of non‐racemic epoxides of defined absolute configuration.
Tradeoffs and sexual conflict over women's fertility preferences in Mpimbwe
Authors: Mulder Monique Borgerhoff 
Published: March 2009

AbstractThere are two principle evolutionary models for why women reduce their fertility, which can be used to explain the modern demographic transition. The first derives from optimality theory (specifically the “quantity‐quality” tradeoff hypothesis), and the second from models of biased cultural transmission (“prestige bias” and “kin influence” hypotheses). Data on family planning preferences collected in 1996 and 1998 in a rural African village (in Mpimbwe, Tanzania) are used to test predictions derived from each hypothesis and show that both “quantity‐quality” tradeoffs and biased cultural transmission underlie Pimbwe women's decisions. Reproductive decisions, however, are not made in a vacuum. Men and women's ideal family sizes often differ, and sexual conflict is particularly likely to affect a woman's success in limiting her family size. Pimbwe women's reproductive output between the initial family planning survey in 1996 and the most recent demographic survey (2006) is analyzed in relation to both the woman's preferences to limit her family and her exposure to husbands and husbands' kin. Despite wide differences in desired family sizes between men and women the extent of sexual conflict in this population is restricted to husbands and wives, and affects not a woman's use or planned use of modern contraception but her success in employing such methods effectively. There is also some evidence that a woman's mother and her kin assist in the use and effective use of modern methods, offering a prevailing force to the high‐fertility objectives of the husband. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.
Relatives as spouses: Preferences and opportunities for kin marriage in a Western society
Authors: Bras Hilde , Van Poppel Frans , Mandemakers Kees 
Published: March 2009

AbstractThis article investigates the determinants of kin marriage on the basis of a large‐scale database covering a major rural part of The Netherlands during the period 1840–1922. We studied three types of kin marriage: first cousin marriage, deceased spouse's sibling marriage, and sibling set exchange marriage. Almost 2% of all marriages were between first cousins, 0.85% concerned the sibling of a former spouse, while 4.14% were sibling set exchange marriages. While the first two types generally declined across the study period, sibling set exchange marriage reached a high point of almost 5% between 1890 and 1900. We found evidence for three mechanisms explaining the choice for relatives as spouses, centering both on preferences and on opportunities for kin marriage. Among the higher and middle strata and among farmers, kin marriages were commonly practiced and played an important role in the process of social class formation in the late nineteenth century. An increased choice for cousin marriage as a means of enculturation was observed among orthodox Protestants in the Bible Belt area of The Netherlands. Finally, all studied types of kin marriage took place more often in the relatively isolated, inland provinces of The Netherlands. Sibling set exchange marriages were a consequence of the enlarged supply of same‐generation kin as a result of the demographic transition. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.
Durch oberflächeninitiierte Suzuki‐Polykondensation zu gepfropftem Polyfluoren
Authors: Beryozkina Tetyana , Boyko Ksenia , Khanduyeva Natalya , Senkovskyy Volodymyr , Horecha Marta , Oertel Ulrich , Simon Frank , Stamm Manfred , Kiriy Anton 
Published: March 2009

AbstractAufgepfropft: Erstmals wurde eine oberflächeninitiierte und regioselektive palladiumkatalysierte Suzuki‐Polykondensation entwickelt, die eine selektive Pfropfung und Strukturierung von halbleitendem und fluoreszierendem Poly(9,9‐bis(2‐ethylhexyl)fluoren) (1) bei Raumtemperatur ermöglicht (siehe Schema). Der Einschub rechts unten zeigt die AFM‐Topographie der strukturierten Oberfläche (Si‐, Glas‐ oder Quarzträger).magnified image
Tough Supersoft Sponge Fibers with Tunable Stiffness from a DNA Self‐Assembly Technique
Authors: Lee Chang Kee , Shin Su Ryon , Mun Ji Young , Han Sung‐Sik , So Insuk , Jeon Ju‐Hong , Kang Tong Mook , Kim Sun I. , Whitten Philip G , Wallace Gordon G. , Spinks Geoffrey M. , Kim Seon Jeong 
Published: March 2009

AbstractTough and soft: Highly porous, spongelike materials self‐assemble by calcium ion condensation of DNA‐wrapped carbon nanotubes (SWNTs–DNA; see picture, IL=ionic liquid). The toughness, modulus, and swellability of the electrically conductive sponges can be tuned by controlling the density and strength of interfiber junctions. The sponges have compliances similar to the softest natural tissue, while robust interfiber junctions give high toughness.magnified image
Grafting of Polyfluorene by Surface‐Initiated Suzuki Polycondensation
Authors: Beryozkina Tetyana , Boyko Ksenia , Khanduyeva Natalya , Senkovskyy Volodymyr , Horecha Marta , Oertel Ulrich , Simon Frank , Stamm Manfred , Kiriy Anton 
Published: March 2009

AbstractGraft work: The first surface‐initiated and site‐specific palladium‐catalyzed Suzuki polycondensation that allows selective grafting and patterning of semiconducting and emissive poly[9,9‐bis(2‐ethylhexyl)fluorene] (1) at room temperature is developed (see scheme). The pattering is demonstrated by AFM (see image).magnified image
Synthesis and characterization of star‐branched polyisobutylene with SIpS triblock copolymer core
Authors: Wu Yibo , Guo Wenli , Li Shuxin , Gong Huiqing 
Published: March 2009

AbstractWell‐defined polystyrene‐b‐polyisoprene‐b‐polystyrene (SIpS) triblock copolymers with different microstructures were synthesized by living anionic polymerization. The synthesis of star‐branched polyisobutylene (PIB) was accomplished by the cationic polymerization in 2‐chloro‐2,4,4‐trimethylpentane/titanium tetrachloride/SIpS triblock copolymer/2,6‐di‐tert‐butylpyridine initiating system. The double bonds in SIpS triblock copolymer were activated as starting points for isobutylene polymerization. The formation of star‐branched architecture was demonstrated by size‐exclusion chromatography with quadruple detection: refractive index, multiangle laser light scattering, viscometric, and ultraviolet detectors. SIpS triblock copolymer with high 3,4‐PIp content is more reactive than that with high 1,4‐PIp content in cationic initiating stage. The yields of star‐branched PIB were remarkably dependent on the reaction time of TMP+ with SIpS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Ultrathin Organically Modified Silica Layer Coated Carbon Nanotubes: Fabrication, Characterization and Electrical Insulating Properties
Authors: Pumera Martin , Sasaki Toshio , Šmíd Břetislav 
Published: March 2009

AbstractNice coat! Organically modified silica (ormosil) is used for the ultrathin nanoprecise coating of individual multiwall carbon nanotubes using a soft‐chemistry approach. The coating layer has a uniform thickness of about 3 nm. The ormosil coating demonstrates the favorable electrical insulating properties of individual multiwall carbon nanotubes.magnified imageThis paper describes the use of organically modified silica (ormosil) for the ultrathin nanoprecise coating of individual multiwall carbon nanotubes using a soft‐chemistry approach. Hybrid organic/inorganic ormosil nanocoated carbon nanotubes were successfully prepared by in‐situ deposition of 3‐aminopropyltrimethoxysilane or N‐methylaminopropyltrimethoxysilane in an aqueous suspension by means of their electrostatic interactions with carboxylic group functionalized multiwall carbon nanotubes. The coating layer was found to have a uniform thickness of about 3 nm. The products were characterized by high‐angle annular dark field scanning transmission electron microscopy, high‐resolution transmission electron microscopy (HR‐TEM), TEM/energy‐dispersive X‐ray spectroscopy, TEM/electron energy loss spectroscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy, and current–voltage measurements. The ormosil coatings demonstrated the favorable electrical insulating properties of individual multiwall carbon nanotubes. We also show that the resistance of the insulating thin layer can be tuned by altering the substituents of alkylmethoxysilanes.
Projected mature technology scenarios for conversion of cellulosic biomass to ethanol with coproduction thermochemical fuels, power, and/or animal feed protein
Authors: Laser Mark , Jin Haiming , Jayawardhana Kemantha , Dale Bruce E. , Lynd Lee R. 
Published: March 2009

AbstractSeven process designs for producing ethanol and several coproducts from switchgrass are evaluated: four involving combinations of ethanol, thermochemical fuels (including Fischer‐Tropsch liquids, hydrogen, and methane) and/or power, and three coproducing animal feed protein. Material and energy balances – resulting from detailed Aspen Plus models – are reported and used to estimate processing costs and perform discounted cash flow analysis to assess plant profitability. In these mature technology designs, fossil fuel displacement is decidedly positive and production costs competitive with gasoline. © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd
Directed Biosynthesis of Phytotoxic Alkaloids in the Cyanobacterium Nostoc 78–12A
Authors: Portmann Cyril , Prestinari Cora , Myers Theresa , Scharte Judith , Gademann Karl 
Published: March 2009

AbstractOut of the green! Precursor‐directed biosynthesis allowed for the production of new nostocarboline derivatives that display phytotoxic and algicidal properties—in a phototrophic organism. The mechanism of action includes downregulation of photosynthesis, as demonstrated by chlorophyll‐a fluorescence imaging.magnified imageNostocarboline, a chlorinated and N‐methylated carbolinium alkaloid, displays potent and selective inhibition of photoautotrophic organisms as well as the malaria parasite Plasmodium falciparum, while showing very low toxicity to bacterial and fungal pathogens, rat myoblasts and crustaceans. New derivatives of nostocarboline incorporating Br, F or methyl substituents have been obtained through precursor‐directed biosynthesis in Nostoc 78–12A (identical to Nostoc sp. ATCC 43238) by feeding this cyanobacterium with differently substituted tryptophan derivatives or 6‐Br‐norharmane (eudistomin N). These experiments substantiate the biosynthetic hypothesis and validate the inherent flexibility of the corresponding enzymes for metabolic engineering. The new derivatives inhibit the growth of the toxic‐bloom‐forming cyanobacterium Microcystis aeruginosa PCC 7806 above 1 μM. The mode of action of nostocarboline was investigated by using chlorophyll‐a fluorescence imaging, and it was demonstrated that a decrease in photosynthesis precedes cell death, thus establishing the phytotoxic properties of this alkaloid.
Benzenoid and Quinonoid Nitrogen‐Containing Heteropentacenes
Authors: Tang Qin , Liu Jing , Chan Hoi Shan , Miao Qian 
Published: March 2009

AbstractBenzenoid or quinonoid—that is the question? In connection with the debate on the structure of dihydro‐5,7,12,14‐tetraazapentacene, both benzenoid and quinonoid nitrogen‐containing heteropentacenes were successfully isolated and investigated (see picture). This report presents an exploratory study of the molecular and electronic structures, molecular packing, and semiconductor properties of the two compounds. These findings may lead to useful implications for the interesting ladder polymers.magnified image
Morphological properties of chick retinal ganglion cells in relation to their central projections
Authors: Chen Yaoxing , Naito Jumpei 
Published: March 2009

AbstractMorphological properties of chick retinal ganglion cells (RGCs) were studied in relation to their central projections in 23 chicks. A total of 217 RGCs were retrogradely labeled by applying a carbocyanine dye (DiI) to the thalamus and optic tectum. The labeled RGCs were classified into six groups on the basis of their somal areas, dendritic fields, and branching patterns. The dendrites of these RGCs extended horizontally in the inner plexiform layer (IPL) forming eight dendritic strata. The RGCs in each group showed certain specificities in their central projections. Group Ic predominantly projected to the tectum. Groups IIs and IIIs showed a high thalamic dominance. Groups Is and IIc were nonspecific with regard to their tectal and thalamic projections. Group IVc showed tectal‐specific projections. Occurrence rates of the dendritic strata increased progressively toward the inner part of the IPL, i.e., DSs (dendritic strata) 1–4 were scantily distributed, DSs 5 and 6 were moderately distributed, and DSs 7 and 8 were the most frequently distributed. A total of 42 dendritic stratification patterns were identified, and of these, 18 patterns were common to the tectal RGCs (tec‐RGCs) and thalamic RGCs (tha‐RGCs). The common patterns were detected very frequently in the tec‐ and tha‐RGCs (≈85%), and the dendritic strata were largely distributed in the inner part of the IPL (DSs 5–8). In contrast, the remaining 24 noncommon stratification patterns showed low occurrence rates (≈15%); however, these dendritic strata were widely distributed in both the outer (DSs 1–4) and inner (DSs 5–8) IPL. J. Comp. Neurol. 514:117–130, 2009. © 2009 Wiley‐Liss, Inc.
Chiral Induction, Memory, and Amplification in Porphyrin Homoaggregates Based on Electrostatic Interactions
Authors: Zeng LiXi , He Yujian , Dai Zhifeng , Wang Jian , Cao Qian , Zhang Yuliang 
Published: March 2009

AbstractSupramolecular chirality in two configurational homoaggregates of anionic meso‐tetrakis(4‐sulfonatophenyl)porphyrin (TPPS) can be induced by D‐ and L‐alanine in acidic water (see picture). The chirality can be further memorized and enforced through strong electrostatic interactions between TPPS aggregates and achiral poly(allylamine) [PAA].magnified imageSupramolecular chirality in two configurational homoaggregates of anionic meso‐tetrakis(4‐sulfonatophenyl)porphyrin (TPPS) can be induced by D‐ and L‐alanine (Ala) in acidic water, respectively. The induced supramolecular chirality can be further memorized and enforced, even after complete removal of Ala or in the presence of excess Ala with the opposite configuration, through strong electrostatic interactions with achiral poly(allylamine) [PAA]. The ionic chiral interactions between TPPS and Ala or PAA are characterized by means of UV/Vis absorption and circular dichroism spectrometry. Fluorescence spectroscopy and atomic force microscopy are used as complementary techniques. On the basis of the comprehensive experimental results, a possible mechanism for chiral induction, memory, and amplification of TPPS homoaggregates by chiral amino acids and achiral PAA is proposed. Thus, we demonstrate a novel strategy to realize chiral memory in supramolecular systems by polyelectrolytes through hierarchical electrostatic self‐assembly.