bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suppression of Peroxisome Proliferator-Activated Receptor γ-Coactivator-1α Normalizes the Glucolipotoxicity-Induced Decreased BETA2/NeuroD Gene Transcription and Improved Glucose Tolerance in Diabetic Rats
Authors: Kim Ji-Won , You Young-Hye , Ham Dong-Sik , Cho Jae-Hyoung , Ko Seung-Hyun , Song Ki-Ho , Son Ho-Young , Suh-Kim Haeyoung , Lee In-Kyu , Yoon Kun-Ho 
Published: June 2009

Abstract
Peroxisome proliferator-activated receptor γ-coactivator-1α (PGC-1α) is significantly elevated in the islets of animal models of diabetes. However, the molecular mechanism has not been clarified. We investigated whether the suppression of PGC-1α expression protects against β-cell dysfunction in vivo and determined the mechanism of action of PGC-1α in β-cells. The studies were performed in glucolipotixicity-induced primary rat islets and INS-1 cells. In vitro and in vivo approaches using adenoviruses were used to evaluate the role of PGC-1α in glucolipotoxicity-associated β-cell dysfunction. The expression of PGC-1α in cultured β-cells increased gradually with glucolipotoxicity. The overexpression of PGC-1α also suppressed the expression of the insulin and β-cell E-box transcription factor (BETA2/NeuroD) genes, which was reversed by PGC-1α small interfering RNA (siRNA). BETA2/NeuroD, p300-enhanced BETA2/NeuroD, and insulin transcriptional activities were significantly suppressed by Ad-PGC-1α but were rescued by Ad-siPGC-1α. PGC-1α binding at the glucocorticoid receptor site on the BETA2/NeuroD promoter increased in the presence of PGC-1α. Ad-siPGC-1α injection through the celiac arteries of 90% pancreatectomized diabetic rats improved their glucose tolerance and maintained their fasting insulin levels. The suppression of PGC-1α expression protects the glucolipotoxicity-induced β-cell dysfunction in vivo and in vitro. A better understanding of the functions of molecules such as PGC-1α, which play key roles in intracellular fuel regulation, could herald a new era of the treatment of patients with type 2 diabetes mellitus by providing protection from glucolipotoxicity, which is an important cause of the development and progression of the disease.
A novel tilapia prolactin receptor is functionally distinct from its paralog
Authors: Fiol Diego F. , Sanmarti Enio , Sacchi Romina , Kültz Dietmar 
Published: June 2009

SUMMARY
A novel tilapia prolactin (PRL) receptor (OmPRLR2) was identified based on its induction during hyperosmotic stress. OmPRLR2 protein shows 28% identity to tilapia OmPRLR1 and 26% identity to human PRLR. Comparison of OmPRLR1 and OmPRLR2 revealed conserved features of cytokine class I receptors (CKR1): a WS domain and transmembrane domain, two pairs of cysteines and N-glycosylation motifs in the extracellular region, CKR1 boxes I and II, and three tyrosines in the intracellular region. However, OmPRLR2 lacked the ubiquitin ligase and 14-3-3 binding motifs. OmPRLR2 mRNA was present in all tissues analyzed, with highest expression in gills, intestine, kidney and muscle, similar to OmPRLR1. Transfer of fish from fresh water to sea water transiently increased gill OmPRLR2 mRNA levels within 4 h but decreased its protein abundance in the long term. OmPRLR2 is expressed in part as a truncated splice variant of 35 kDa in addition to the 55 kDa full-length protein. Cloning of the mRNA encoding the 35 kDa variant revealed that it lacks the extracellular region. It is expressed at significantly higher levels in males than in females. In stably transfected HEK293 cells over-expressing tetracycline-inducible OmPRLR1 and OmPRLR2, activation of these receptors by tilapia PRL177 and PRL188 triggered different downstream signaling pathways. Moreover, OmPRLR2 significantly increased HEK293 salinity tolerance. Our data reveal that tilapia has two PRLR genes whose protein products respond uniquely to PRL and activate different downstream pathways. Expression of a short PRLR2 variant may serve to inhibit PRL binding during osmotic stress and in male tissues.
Decoupling development and energy flow during embryonic diapause in the cricket,Allonemobius socius
Authors: Reynolds Julie A. , Hand Steven C. 
Published: June 2009

SUMMARYRespiration rate increases 6.3-fold during 15 days of post-oviposition development in embryos of the Southern ground cricket, Allonemobius socius. This ontogenetic increase in metabolism of non-diapause insects is blocked during diapause, such that metabolic rate is only 36% of the rate measured for 15 days developing embryos. Surprisingly, however, there is not an acute metabolic depression during diapause entry at the point when developmental ceases (4–5 days post-oviposition), as measured by blockage of morphological change and DNA proliferation. The results indicate a decoupling of developmental arrest from metabolism. Both non-diapause and diapause embryos have unusually high [AMP]:[ATP] ratios and low [ATP]:[ADP]ratios during early embryogenesis, which suggests embryos may have experienced hypoxia as a result of an insect chorion that limits water loss but may restrict oxygen diffusion. The similar adenylate profiles for these two developmental states indicate the atypical energy status is not a specific feature of diapause. In addition embryos at day 3 have high levels of lactate that decrease as development proceeds up to day 7. Calorimetric-respirometric(CR) ratios of –353 (day 3) to –333 (day 7) kJ mol–1 O2 are consistent with embryos that are aerobically recovering from hypoxia, but are inconsistent with an ongoing anaerobic contribution to metabolism. Superfusing 3-day embryos with O2 enriched air (40% O2) forces these metabolic indicators toward a more aerobic poise, but only partially. Taken together these biochemical data indicate the metabolic poise of A. socius is only partly explained by hypoxia in early development, and that the atypical set points are also intrinsic features of this ontogenetic period in the life cycle.
Dynamics of goat distal hind limb muscle–tendon function in response to locomotor grade
Authors: McGuigan M. Polly , Yoo Edwin , Lee David V. , Biewener Andrew A. 
Published: June 2009

SUMMARYThe functional roles of the lateral gastrocnemius (LG), medial gastrocnemius (MG) and superficial digital flexor (SDF) muscle–tendon units (MTUs) in domestic goats (N=6) were studied as a function of locomotor grade, testing the hypothesis that changes in distal limb muscle work would reflect changes in mechanical work requirements while goats walked or trotted on the level, 15 deg. decline and 15 deg. incline. As steep terrain-adapted animals, changes in muscle work output are expected to be particularly important for goats. In vivo muscle–tendon forces,fascicle length changes and muscle activation were recorded viatendon force buckles, sonomicrometry and electromyography to evaluate the work performance and elastic energy recovery of the three distal MTUs. These recordings confirmed that fascicle strain and force within goat distal hind limb muscles are adjusted in response to changes in mechanical work demand associated with locomotor grade. In general, muscle work was modulated most consistently by changes in fascicle strain, with increased net shortening(P&lt;0.001) observed as goats switched from decline to level to incline locomotion. Peak muscle stresses increased as goats increased speed from a walk to a trot within each grade condition (P&lt;0.05), and also increased significantly with grade (P&lt;0.05 to P&lt;0.01). Due to the increase in net fascicle shortening and muscle force, net muscle work per cycle also increased significantly(P&lt;0.05 to P&lt;0.005) as goats switched from decline to level to incline conditions (LG work: 20 mJ to 56 mJ to 209 mJ; MG work:–7 mJ to 34 mJ to 179 mJ; SDF work: –42 mJ to 14 mJ to 71 mJ, at a 2.5 ms–1 trot). Although muscle work was modulated in response to changes in grade, the amount of work produced by these three distal pennate muscles was small (being &lt;3%) in comparison with the change in mechanical energy required of the limb as a whole. Elastic energy recovery in the SDF and gastrocnemius (GA) tendons was substantial across all three grades, with the SDF tendon recovering 2.4 times more energy, on average, than the GA tendon. In parallel with the increase in muscle–tendon force,tendon energy recovery also increased as goats increased speed and changed gait, reaching the highest levels when goats trotted on an incline at 2.5 ms–1 (GA: 173 mJ; SDF: 316 mJ). In general, tendon elastic energy exceeded net muscle work across all grade and gait conditions. These results demonstrate, for the first time in a quadruped, similar findings to those observed in ankle extensor muscles in humans, wallabies, turkeys and guinea fowl, suggesting that distal muscle–tendon architecture more generally favors a design for economic force production and tendon elastic energy recovery, with the majority of limb work during incline or decline running performed by larger proximal muscles.
Spider silk as a novel high performance biomimetic muscle driven by humidity
Authors: Agnarsson Ingi , Dhinojwala Ali , Sahni Vasav , Blackledge Todd A. 
Published: June 2009

SUMMARY
The abrupt halt of a bumble bee's flight when it impacts the almost invisible threads of an orb web provides an elegant example of the amazing strength and toughness of spider silk. Spiders depend upon these properties for survival, yet the impressive performance of silk is not limited solely to tensile mechanics. Here, we show that silk also exhibits powerful cyclic contractions, allowing it to act as a high performance mimic of biological muscles. These contractions are actuated by changes in humidity alone and repeatedly generate work 50 times greater than the equivalent mass of human muscle. Although we demonstrate that this response is general and occurs weakly in diverse hydrophilic materials, the high modulus of spider silk is such that it generates exceptional force. Furthermore, because this effect already operates at the level of single silk fibers, only 5 μm in diameter,it can easily be scaled across the entire size range at which biological muscles operate. By contrast, the most successful synthetic muscles developed so far are driven by electric voltage, such that they cannot scale easily across large ranges in cross-sectional areas. The potential applicability of silk muscles is further enhanced by our finding that silkworm fibers also exhibit cyclic contraction because they are already available in commercial quantities. The simplicity of using wet or dry air to drive the biomimetic silk muscle fibers and the incredible power generated by silk offer unique possibilities in designing lightweight and compact actuators for robots and micro-machines, new sensors, and green energy production.
How super is supercontraction? Persistent versus cyclic responses to humidity in spider dragline silk
Authors: Blackledge Todd A. , Boutry Cecilia , Wong Shing-Chung , Baji Avinash , Dhinojwala Ali , Sahni Vasav , Agnarsson Ingi 
Published: June 2009

SUMMARY
Spider dragline silk has enormous potential for the development of biomimetic fibers that combine strength and elasticity in low density polymers. These applications necessitate understanding how silk reacts to different environmental conditions. For instance, spider dragline silk`supercontracts' in high humidity. During supercontraction, unrestrained dragline silk contracts up to 50% of its original length and restrained fibers generate substantial stress. Here we characterize the response of dragline silk to changes in humidity before, during and after supercontraction. Our findings demonstrate that dragline silk exhibits two qualitatively different responses to humidity. First, silk undergoes a previously unknown cyclic relaxation–contraction response to wetting and drying. The direction and magnitude of this cyclic response is identical both before and after supercontraction. By contrast, supercontraction is a `permanent' tensioning of restrained silk in response to high humidity. Here, water induces stress,rather than relaxation and the uptake of water molecules results in a permanent change in molecular composition of the silk, as demonstrated by thermogravimetric analysis (TGA). Even after drying, silk mass increased by∼1% after supercontraction. By contrast, the cyclic response to humidity involves a reversible uptake of water. Dried, post-supercontraction silk also differs mechanically from virgin silk. Post-supercontraction silk exhibits reduced stiffness and stress at yield, as well as changes in dynamic energy storage and dissipation. In addition to advancing understanding supercontraction, our findings open up new applications for synthetic silk analogs. For example, dragline silk emerges as a model for a biomimetic muscle, the contraction of which is precisely controlled by humidity alone.
Fingerprints are unlikely to increase the friction of primate fingerpads
Authors: Warman Peter H. , Ennos A. Roland 
Published: June 2009

SUMMARYIt is generally assumed that fingerprints improve the grip of primates, but the efficiency of their ridging will depend on the type of frictional behaviour the skin exhibits. Ridges would be effective at increasing friction for hard materials, but in a rubbery material they would reduce friction because they would reduce contact area. In this study we investigated the frictional performance of human fingertips on dry acrylic glass using a modified universal mechanical testing machine, measuring friction at a range of normal loads while also measuring the contact area. Tests were carried out on different fingers, fingers at different angles and against different widths of acrylic sheet to separate the effects of normal force and contact area. The results showed that fingertips behaved more like rubbers than hard solids;their coefficients of friction fell at higher normal forces and friction was higher when fingers were held flatter against wider sheets and hence when contact area was greater. The shear stress was greater at higher pressures,suggesting the presence of a biofilm between the skin and the surface. Fingerprints reduced contact area by a factor of one-third compared with flat skin, however, which would have reduced the friction; this casts severe doubt on their supposed frictional function.
Hearing ability in three clownfish species
Authors: Parmentier Eric , Colleye Orphal , Mann David 
Published: June 2009

SUMMARYClownfish live in social groups in which there is a size-based dominance hierarchy. In such a context, sonic cues could play a role in social organisation because dominant frequency and pulse length of sounds are strongly correlated with fish size. Data on the hearing ability of these fish are, however, needed to show that they have the sensory ability to detect the frequencies in their sounds. The present study determines the hearing sensitivity in three different anemonefish species (Amphiprion frenatus,Amphiprion ocellaris and Amphiprion clarkii), and compares it with the frequencies in their calls. The frequency range over which the three species can detect sounds was between 75 and 1800 Hz, and they were most sensitive to frequencies below 200 Hz. During sound production, dominant frequency is clearly related (R=0.95) to the fish size, whatever the species. Dominant frequency extends from 370 to 900 Hz for specimens having a size between 55 and 130 mm. The best hearing sensitivity of small specimens were found to be lower than the dominant frequency of their own calls. However, they were found to be close to the dominant frequency of larger fish calls. The interest of juveniles lies in localising the adults and thus their location on the reef.
Phthalocyanine, Porphyrin, Cyclodextrin, and Polymer Systems Suitable for Studying by Circular Dichroism, Magnetic Circular Dichroism, and/or Electrochemistry
Authors: Kobayashi Nagao , Fukuda Takamitsu 
Published: June 2009

Abstract
We introduce some representative studies from our laboratory, mostly from the 21st Century. We are interested in the synthesis, optical spectroscopy, such as magnetic circular dichroism (MCD), circular dichroism (CD), and electrochemistry of large aromatic molecules such as porphyrins and phthalocyanines, as well as cyclodextrin and polymer systems showing CD activity.
Effect of Hydration on the Very Slow Droplet–Lamellar Transition in Dioleylsulfosuccinate/Decane/Water System: A Small Angle X-ray Scattering Study
Authors: Ghosh Swapan K , Ichiyanagi Naoki , Okabayashi Hiro-Fumi , Yoshino Aki-Hiro , Takeda Takayoshi , O’Connor Charmian J 
Published: June 2009

Abstract
Time- and temperature-dependence of the small angle X-ray scattering (SAXS) profiles for homogeneous and transparent solutions of the sodium dioleylsulfosuccinate (SDOleS)–decane–water system with various molar ratios of [H2O]/[SDOleS] have been examined. The time-dependence of the SAXS profiles has provided evidence that the droplet–lamellar transition occurs spontaneously but very slowly at 298 K. This behavior depends upon the quantity of water solubilized into the SDOleS microemulsions. Some microstructural models have been proposed to explain this very slow transition.
Aromaticity and Conjugation in Sapphyrin and Orangarin
Authors: Aihara Jun-ichi , Makino Masakazu 
Published: June 2009

Abstract
We analyzed aromatic and magnetic properties of two typical expanded porphyrins, sapphyrin and orangarin, using our theory of aromaticity and ring-current diamagnetism and confirmed that, as in the case of free-base porphine, global aromaticity and macrocyclic circulation are associated primarily with five pyrrolic rings and the macrocyclic annulenoid pathway, respectively. For orangarin, the main pathway of macrocyclic circulation is different from the [20]annulene pathway so far proposed as a main macrocyclic conjugation pathway. A new method was proposed for associating the main macrocyclic conjugation pathway with the π-current density pattern.
Purity Effects on the Charge-Transport Properties in One-Dimensional TPP[CoIII(Pc)(CN)2]2 (TPP = Tetraphenylphosphonium and Pc = Phthalocyaninato) Conductors
Authors: Yamashita Satoshi , Naito Toshio , Inabe Tamotsu 
Published: June 2009

Abstract
Purity effects on the temperature dependence of electrical resistivity in TPP[Co(Pc)(CN)2]2 with a typical one-dimensional metallic electronic system have been examined. In this system, no dependence on the impurity content has been observed, suggesting that the apparent thermally activated behavior is dominated by charge disproportionation.
Chloride Complexation of Zr and Hf in HCl Investigated by Extended X-ray Absorption Fine Structure Spectroscopy: Toward Characterization of Chloride Complexation of Element 104, Rutherfordium (Rf)
Authors: Haba Hiromitsu , Akiyama Kazuhiko , Tsukada Kazuaki , Asai Masato , Toyoshima Atsushi , Yaita Tsuyoshi , Hirata Masaru , Sueki Keisuke , Nagame Yuichiro 
Published: June 2009

Abstract
Chloride complexation of the group-4 elements Zr and Hf in 8.0–11.9 M HCl is investigated by extended X-ray absorption fine structure (EXAFS) spectroscopy to characterize chloro complexes of the transactinide element, rutherfordium (Rf). The complexes of Zr and Hf successively vary with the concentration of HCl from a hydrated complex [M(H2O)8]4+ at 8.0 M to a hexachloro complex [MCl6]2− at 11.9 M (M = Zr and Hf). The present structural changes of the Zr and Hf complexes well reflect the previously studied anion-exchange behavior of Zr and Hf in HCl. From both the EXAFS and anion-exchange results, we suggest that Rf forms the same complexes as those of Zr and Hf in HCl, and that the complexation strength of the hexachloro complexes of the group-4 elements, [MCl6]2− (M = Zr, Hf, and Rf), is in the sequence of Rf &gt; Zr &gt; Hf.
Synthesis and Photochemical Characteristics of Amphiphilic Enediyne Dendrimers
Authors: Yoshimura Nao , Momotake Atsuya , Shinohara Yoshihiro , Takahashi Kayori , Nagahata Ritsuko , Nishimura Yoshinobu , Arai Tatsuo 
Published: June 2009

Abstract
Amphiphilic enediyne-cored dendrimers were prepared as pure cis and trans isomers. All dendrimers were fluorescent to give fluorescence quantum yield of 0.10–0.64, and they underwent efficient photochemical isomerization with quantum yields of 0.22–0.50 in THF. In water, other photochemical reactions took place. Fluorescence or triplet lifetimes were also strongly affected by dendrimer generation and solvent polarity. The structure–photochemical property relationship of new photoresponsive dendrimers is discussed.
Photolysis of 1,2-Naphthoquinone in Oxygen-Doped Argon Matrix at Low Temperature
Authors: Itoh Takayoshi , Tatsugi Jiro , Tomioka Hideo 
Published: June 2009

Abstract
Photolysis of 1,2-naphthoquinone (1) in argon matrix either with or without oxygen at 10 K was investigated by IR spectroscopy in combination with DFT calculations. The results indicate that 1 gave bis(ketene) 2 as a main product along with a small amount of inden-1-one (4), most probably as a result of Type I cleavage, followed by electron reorganization and decarbonylation in the resulting diacyl radical, respectively. Bis(ketene) 2 was shown to transform to isomeric ketene 3 upon continued irradiation under these conditions. When the irradiation was carried out in argon matrix doped with 20% oxygen, 1 decomposed much more efficiently than that in argon matrix and six- and eight-membered cyclic peroxides presumably formed by trapping of initial diradical originating from α-cleavage by molecular oxygen were detected at complete expense of 3 and 4. The formation of 2 even in the presence of oxygen suggested that 2 may partly be formed by a concerted pathway in the singlet excited state. The present observation reveals that photolysis of α-diketones in oxygen-doped matrix at low temperature provides useful information concerning the reaction pathway of the diketone upon photoexcitation.
A Stable Electroactive Monolayer Composed of Soluble Single-Walled Carbon Nanotubes on ITO
Authors: Wang Qiguan , Moriyama Hiroshi 
Published: June 2009

Abstract
Self-assembled monolayers (SAMs) of single-walled carbon nanotubes (SWNTs) covalently attached to a (3-aminopropyl)trimethoxysilane-modified ITO surface (SAM–ITO) were prepared by the coupling reaction of the amine groups with the carboxyl groups from the soluble SWNTs, which were safely obtained via a two-step process assisted by microwave irradiation. The surface composition of the SAM–ITO was examined using X-ray photoelectron spectroscopy. The cyclic voltammetry (CV) behavior of the SAM–ITO in an organic system showed a higher capacitor charging current, which indicated the presence of a tethered SWNT monolayer. However, the CV behavior of the SAM–ITO in acidic aqueous solutions showed unexpected oxidation signals because of redox reactions involving the defects and sidewalls of soluble functionalized SWNTs. To make the CVs of the resulting SWNT monolayers more stable in acidic aqueous solutions, a conductive oligomer of tetramer aniline was additionally incorporated onto the residual carboxyl groups on the SWNTs. The UV–vis spectrum showed that the SWNT monolayer was successfully endcapped by the conductive oligomer, and atomic force microscopy images showed that the SWNTs from the self-assembled monolayer were thickened and the SWNT surfaces were roughened. The CV data showed a single reversible redox couple, which indicated a more stable state.