bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multivariate selection drives concordant patterns of pre- and postcopulatory sexual selection in a livebearing fish
Authors: Devigili Alessandro , Evans Jonathan P. , Di Nisio Andrea , Pilastro Andrea 
Published: September 2015

AbstractIn many species, females mate with multiple partners, meaning that sexual selection on male traits operates across a spectrum that encompasses the competition for mates (that is, before mating) and fertilizations (after mating). Despite being inextricably linked, pre- and postcopulatory sexual selection are typically studied independently, and we know almost nothing about how sexual selection operates across this divide. Here we bridge this knowledge gap using the livebearing fish Poecilia reticulata. We show that both selective episodes, as well as their covariance, explain a significant component of variance in male reproductive fitness. Moreover, linear and nonlinear selection simultaneously act on pre- and postcopulatory traits, and interact to generate multiple phenotypes with similar fitness.
How Leiomodin and Tropomodulin use a common fold for different actin assembly functions
Authors: Boczkowska Malgorzata , Rebowski Grzegorz , Kremneva Elena , Lappalainen Pekka , Dominguez Roberto 
Published: September 2015

AbstractHow proteins sharing a common fold have evolved different functions is a fundamental question in biology. Tropomodulins (Tmods) are prototypical actin filament pointed-end-capping proteins, whereas their homologues, Leiomodins (Lmods), are powerful filament nucleators. We show that Tmods and Lmods do not compete biochemically, and display similar but distinct localization in sarcomeres. Changes along the polypeptide chains of Tmods and Lmods exquisitely adapt their functions for capping versus nucleation. Tmods have alternating tropomyosin (TM)- and actin-binding sites (TMBS1, ABS1, TMBS2 and ABS2). Lmods additionally contain a C-terminal extension featuring an actin-binding WH2 domain. Unexpectedly, the different activities of Tmods and Lmods do not arise from the Lmod-specific extension. Instead, nucleation by Lmods depends on two major adaptations—the loss of pointed-end-capping elements present in Tmods and the specialization of the highly conserved ABS2 for recruitment of two or more actin subunits. The WH2 domain plays only an auxiliary role in nucleation.
Stacked bilayer phosphorene: strain-induced quantum spin Hall state and optical measurement
Authors: Zhang Tian , Lin Jia-He , Yu Yan-Mei , Chen Xiang-Rong , Liu Wu-Ming 
Published: September 2015

AbstractBilayer phosphorene attracted considerable interest, giving a potential application in nanoelectronics owing to its natural bandgap and high carrier mobility. However, very little is known regarding the possible usefulness in spintronics as a quantum spin Hall (QSH) state of material characterized by a bulk energy gap and gapless spin-filtered edge states. Here, we report a strain-induced topological phase transition from normal to QSH state in bilayer phosphorene, accompanied by band-inversion that changes "Equation missing" number from 0 to 1, which is highly dependent on interlayer stacking. When the bottom layer is shifted by 1/2 unit-cell along zigzag/armchair direction with respect to the top layer, the maximum topological bandgap 92.5 meV is sufficiently large to realize QSH effect even at room-temperature. An optical measurement of QSH effect is therefore suggested in view of the wide optical absorption spectrum extending to far infra-red, making bilayer phosphorene a promising candidate for opto-spintronic devices.
Animal movements in the Kenya Rift and evidence for the earliest ambush hunting by hominins
Authors: Kübler Simon , Owenga Peter , Reynolds Sally C. , Rucina Stephen M. , King Geoffrey C. P. 
Published: September 2015

AbstractAnimal movements in the Kenya Rift Valley today are influenced by a combination of topography and trace nutrient distribution. These patterns would have been the same in the past when hominins inhabited the area. We use this approach to create a landscape reconstruction of Olorgesailie, a key site in the East African Rift with abundant evidence of large-mammal butchery between ~1.2 and ~0.5 Ma BP. The site location in relation to limited animal routes through the area show that hominins were aware of animal movements and used the location for ambush hunting during the Lower to Middle Pleistocene. These features explain the importance of Olorgesailie as a preferred location of repeated hominin activity through multiple changes in climate and local environmental conditions and provide insights into the cognitive and hunting abilities of Homo erectus while indicating that their activities at the site were aimed at hunting, rather than scavenging.
The β-cell GHSR and downstream cAMP/TRPM2 signaling account for insulinostatic and glycemic effects of ghrelin
Authors: Kurashina Tomoyuki , Dezaki Katsuya , Yoshida Masashi , Sukma Rita Rauza , Ito Kiyonori , Taguchi Masanobu , Miura Rina , Tominaga Makoto , Ishibashi Shun , Kakei Masafumi , Yada Toshihiko 
Published: September 2015

AbstractGastric hormone ghrelin regulates insulin secretion, as well as growth hormone release, feeding behavior and adiposity. Ghrelin is known to exert its biological actions by interacting with the growth hormone secretagogue-receptor (GHSR) coupled to Gq/11-protein signaling. By contrast, ghrelin acts on pancreatic islet β-cells via Gi-protein-mediated signaling. These observations raise a question whether the ghrelin action on islet β-cells involves atypical GHSR and/or distinct signal transduction. Furthermore, the role of the β-cell GHSR in the systemic glycemic effect of ghrelin still remains to be defined. To address these issues, the present study employed the global GHSR-null mice and those re-expressing GHSR selectively in β-cells. We here report that ghrelin attenuates glucose-induced insulin release via direct interaction with ordinary GHSR that is uniquely coupled to novel cAMP/TRPM2 signaling in β-cells and that this β-cell GHSR with unique insulinostatic signaling largely accounts for the systemic effects of ghrelin on circulating glucose and insulin levels. The novel β-cell specific GHSR-cAMP/TRPM2 signaling provides a potential therapeutic target for the treatment of type 2 diabetes.
Speckle disturbance limit in laser-based cinema projection systems
Authors: Verschaffelt Guy , Roelandt Stijn , Meuret Youri , Van den Broeck Wendy , Kilpi Katriina , Lievens Bram , Jacobs An , Janssens Peter , Thienpont Hugo 
Published: September 2015

AbstractIn a multi-disciplinary effort, we investigate the level of speckle that can be tolerated in a laser cinema projector based on a quality of experience experiment with movie clips shown to a test audience in a real-life movie theatre setting. We identify a speckle disturbance threshold by statistically analyzing the observers’ responses for different values of the amount of speckle, which was monitored using a well-defined speckle measurement method. The analysis shows that the speckle perception of a human observer is not only dependent on the objectively measured amount of speckle, but it is also strongly influenced by the image content. The speckle disturbance limit for movies turns out to be substantially larger than that for still images and hence is easier to attain.
CD8+NKT-like cells regulate the immune response by killing antigen-bearing DCs
Authors: Wang Chao , Liu Xi , Li Zhengyuan , Chai Yijie , Jiang Yunfeng , Wang Qian , Ji Yewei , Zhu Zhongli , Wan Ying , Yuan Zhenglong , Chang Zhijie , Zhang Minghui 
Published: September 2015

AbstractCD1d-dependent NKT cells have been extensively studied; however, the function of CD8+NKT-like cells, which are CD1d-independent T cells with NK markers, remains unknown. Here, we report that CD1d-independent CD8+NKT-like cells, which express both T cell markers (TCRβ and CD3) and NK cell receptors (NK1.1, CD49b and NKG2D), are activated and significantly expanded in mice immunized with GFP-expressing dendritic cells. Distinct from CD1d-dependent NKT cells, CD8+NKT-like cells possess a diverse repertoire of TCRs and secrete high levels of IFN-gamma but not IL-4. CD8+NKT-like cell development is normal in CD1d−/− mice, which suggests that CD8+NKT-like cells undergo a unique development pathway that differs from iNKT cells. Further functional analyses show that CD8+NKT-like cells suppress T-cell responses through elimination of dendritic cells in an antigen-specific manner. Adoptive transfer of antigen-specific CD8+NKT-like cells into RIP-OVA mice prevented subsequent development of diabetes in the animals induced by activated OT-I CD8 T cells. Our study suggests that CD8+NKT-like cells can function as antigen-specific suppressive cells to regulate the immune response through killing antigen-bearing DCs. Antigen-specific down regulation may provide an active and precise method for constraining an excessive immune response and avoiding bypass suppression of necessary immune responses to other antigens.
Manifestation of a Second Dirac Surface State and Bulk Bands in THz Radiation from Topological Insulators
Authors: Tu Chien-Ming , Yeh Tien-Tien , Tzeng Wen-Yen , Chen Yi-Ru , Chen Hsueh-Ju , Ku Shin-An , Luo Chih-Wei , Lin Jiunn-Yuan , Wu Kaung-Hsiung , Juang Jenh-Yih , Kobayashi Takayoshi , Cheng Cheng-Maw , Tsuei Ku-Ding , Berger Helmuth , Sankar Raman , Chou Fang-Cheng 
Published: September 2015

AbstractTopological insulators (TIs) are interesting quantum matters that have a narrow bandgap for bulk and a Dirac-cone-like conducting surface state (SS). The recent discovered second Dirac surface state (SS) and bulk bands (BBs) located ~1.5 eV above the first SS are important for optical coupling in TIs. Here, we report on the time-domain measurements of THz radiation generated from TIs n-type Cu0.02Bi2Se3 and p-type Bi2Te3 single crystals by ultrafast optical pulse excitation. The observed polarity-reversal of the THz pulse originated from transient current is unusual and cannot be reconciled with the photo-Dember effect. The second SS and BBs are found to be indispensable for the explanation of the unusual phenomenon. Thanks to the existence of the second SS and BBs, TIs manifest an effective wide band gap in THz generation. The present study demonstrates that time-domain THz spectroscopy provide rich information of the optical coupling and the electronic structure of TIs.
Supramolecular One-Dimensional n/p-Nanofibers
Authors: Insuasty Alberto , Atienza Carmen , Luis López Juan , Marco-Martínez Juan , Casado Santiago , Saha Avishek , Guldi Dirk M. , Martín Nazario 
Published: September 2015

AbstractCurrently, there is a broad interest in the control over creating ordered electroactive nanostructures, in which electron donors and acceptors are organized at similar length scales. In this article, a simple and efficient procedure is reported en-route towards the construction of 1D arrays of crystalline pristine C60 and phenyl-C61-butyric acid methyl ester (PCBM) coated onto supramolecular fibers based on exTTF-pentapeptides. The resulting n/p-nanohybrids have been fully characterized by a variety of spectroscopic (FTIR, UV-Vis, circular dichroism, Raman and transient absorption), microscopic (AFM, TEM and SEM) and powder diffraction (X-ray) techniques. Our experimental findings document the tendency of electroactive exTTF-fibers to induce the crystallization of C60 and PCBM, on one hand and to afford 1D n/p-nanohybrids, on the other hand. Furthermore, photogenerated radical ion pairs, formed upon visible light irradiation of the n/p-nanohybrids, feature lifetimes on the range of 0.9–1.2 ns.
Large difference in carbon emission – burial balances between boreal and arctic lakes
Authors: Lundin E. J. , Klaminder J. , Bastviken D. , Olid C. , Hansson S. V. , Karlsson J. 
Published: September 2015

AbstractLakes play an important role in the global carbon (C) cycle by burying C in sediments and emitting CO2and CH4to the atmosphere. The strengths and control of these fundamentally different pathways are therefore of interest when assessing the continental C balance and its response to environmental change. In this study, based on new high-resolution estimates in combination with literature data, we show that annual emission:burial ratios are generally ten times higher in boreal compared to subarctic – arctic lakes. These results suggest major differences in lake C cycling between biomes, as lakes in warmer boreal regions emit more and store relatively less C than lakes in colder arctic regions. Such effects are of major importance for understanding climatic feedbacks on the continental C sink – source function at high latitudes. If predictions of global warming and northward expansion of the boreal biome are correct, it is likely that increasing C emissions from high latitude lakes will partly counteract the presumed increasing terrestrial C sink capacity at high latitudes.
Variable telomere length across post-mortem human brain regions and specific reduction in the hippocampus of major depressive disorder
Authors: Mamdani F , Rollins B , Morgan L , Myers R M , Barchas J D , Schatzberg A F , Watson S J , Akil H , Potkin S G , Bunney W E , Vawter M P , Sequeira P A 
Published: September 2015

AbstractStress can be a predisposing factor to psychiatric disorders and has been associated with decreased neurogenesis and reduced hippocampal volume especially in depression. Similarly, in white blood cells chronic psychological stress has been associated with telomere shortening and with mood disorders and schizophrenia (SZ). However, in previous post-mortem brain studies from occipital cortex and cerebellum, no difference in telomere length was observed in depression. We hypothesized that in psychiatric disorders, stress-driven accelerated cellular aging can be observed in brain regions particularly sensitive to stress. Telomere length was measured by quantitative-PCR in five brain regions (dorsolateral prefrontal cortex, hippocampus (HIPP), amygdala, nucleus accumbens and substantia nigra (SN)) in major depressive disorder (MDD), bipolar disorder, SZ and normal control subjects (N=40, 10 subjects per group). We observed significant differences in telomere length across brain regions suggesting variable levels of cell aging, with SN and HIPP having the longest telomeres and the dorsolateral prefrontal cortex the shortest. A significant decrease (P<0.02) in telomere length was observed specifically in the HIPP of MDD subjects even after controlling for age. In the HIPP of MDD subjects, several genes involved in neuroprotection and in stress response (FKBP5, CRH) showed altered levels of mRNA. Our results suggest the presence of hippocampal stress-mediated accelerated cellular aging in depression. Further studies are needed to investigate the cellular specificity of these findings.
Mechanistic understanding of molecular initiating events (MIEs) using NMR spectroscopy
Authors: Sanderson Paul N. , Simpson Wendy , Cubberley Richard , Aleksic Maja , Gutsell Stephen , Russell Paul J. 
Published: September 2015

Abstract
Toxicological risk assessments in the 21st century are increasingly being driven by the Adverse Outcome Pathways (AOP) conceptual framework in which the Molecular Initiating Event (MIE) is of fundamental importance to pathway progression. For those MIEs that involve covalent chemical reactions, such as protein haptenation, determination of relative rates and mechanisms of reactions is a prerequisite for their understanding. The utility of NMR spectroscopy as an experimental technique for effectively providing reaction rate and mechanistic information for early assessment of likely MIE(s) has been demonstrated. To demonstrate the concept, model systems exemplifying common chemical reactions involved in the covalent modification of proteins were utilized; these involved chemical reactions of electrophilic species (representing different mechanistic classes) with simple amine and thiol nucleophiles acting as surrogates for the reactive groups of lysine and cysteine protein side chains respectively. Such molecular interactions are recognized as critical mechanisms in a variety of chemical and drug toxicities, including respiratory and skin sensitization and liver toxicity as well as being the key mechanism of action for a number of therapeutic agents.
Solution NMR characterization of chemokine CXCL8/IL-8 monomer and dimer binding to glycosaminoglycans: structural plasticity mediates differential binding interactions
Authors: Joseph Prem Raj B. , Mosier Philip D. , Desai Umesh R. , Rajarathnam Krishna 
Published: September 2015

Chemokine CXCL8/interleukin-8 (IL-8) plays a crucial role in directing neutrophils and oligodendrocytes to combat infection/injury and tumour cells in metastasis development. CXCL8 exists as monomers and dimers and interaction of both forms with glycosaminoglycans (GAGs) mediate these diverse cellular processes. However, very little is known regarding the structural basis underlying CXCL8–GAG interactions. There are conflicting reports on the affinities, geometry and whether the monomer or dimer is the high-affinity GAG ligand. To resolve these issues, we characterized the binding of a series of heparin-derived oligosaccharides [heparin disaccharide (dp2), heparin tetrasaccharide (dp4), heparin octasaccharide (dp8) and heparin 14-mer (dp14)] to the wild-type (WT) dimer and a designed monomer using solution NMR spectroscopy. The pattern and extent of binding-induced chemical shift perturbation (CSP) varied between dimer and monomer and between longer and shorter oligosaccharides. NMR-based structural models show that different interaction modes coexist and that the nature of interactions varied between monomer and dimer and oligosaccharide length. MD simulations indicate that the binding interface is structurally plastic and provided residue-specific details of the dynamic nature of the binding interface. Binding studies carried out under conditions at which WT CXCL8 exists as monomers and dimers provide unambiguous evidence that the dimer is the high-affinity GAG ligand. Together, our data indicate that a set of core residues function as the major recognition/binding site, a set of peripheral residues define the various binding geometries and that the structural plasticity of the binding interface allows multiplicity of binding interactions. We conclude that structural plasticity most probably regulates in vivo CXCL8 monomer/dimer–GAG interactions and function.
Dietary change among hominins and cercopithecids in Ethiopia during the early Pliocene
Authors: Levin Naomi E. , Haile-Selassie Yohannes , Frost Stephen R. , Saylor Beverly Z. 
Published: September 2015

SignificanceDietary change among hominins is a critical aspect of human evolution. Here we use carbon isotope data from fossil teeth of hominins, monkeys, and other mammals from Ethiopia to document C4food consumption by both hominins and the baboon,Theropithecus oswaldi, during the early Pliocene. The expansion of hominin diet and the appearance of theTheropithecus oswaldilineage as early as 3.76 Ma mark a major ecological change within African primate communities. The ability to eat a range of C3and C4foods indicates that early Pliocene hominins were likely generalists who could thrive in different and perhaps varying environments.
Melting of iron determined by X-ray absorption spectroscopy to 100 GPa
Authors: Aquilanti Giuliana , Trapananti Angela , Karandikar Amol , Kantor Innokenty , Marini Carlo , Mathon Olivier , Pascarelli Sakura , Boehler Reinhard 
Published: September 2015

Significance
There is a long-standing controversy over the melting curve of Fe at high pressure as determined from static laser heated diamond anvil cell and dynamic compression studies. X-ray absorption spectroscopy measurements are used here as a criterion to detect melting under pressure. Confronted with a diversity of obtained melting curves, this technique, used at such pressure and temperature conditions, is eligible to be at the forefront to probe Earth's deep interior. Furthermore, the experiment reported here holds promise for addressing important issues related to the structure and phase diagram of compressed melts, such as the existence of structural complexity (polyamorphism) in the liquid phase or the extent of icosahedral ordering whose investigation has been limited until now to ambient conditions.
Complex constraints on allometry revealed by artificial selection on the wing ofDrosophila melanogaster
Authors: Bolstad Geir H. , Cassara Jason A. , Márquez Eladio , Hansen Thomas F. , van der Linde Kim , Houle David , Pélabon Christophe 
Published: September 2015

SignificanceMany traits scale precisely with size, but it is unknown whether this is due to selection for optimal function or due to evolutionary constraint. We use artificial selection to demonstrate that wing-shape scaling in fruit flies can respond to selection. This evolved response in scaling was lost during a few generations after selection ended, but other selected changes in wing shape persisted. Shape–size scaling in fly wings is therefore evolvable, but adaptation is apparently constrained by selection that may not be on wings. This may explain why scaling relationships are often evolutionarily conserved.
Signal strength regulates antigen-mediated T-cell deceleration by distinct mechanisms to promote local exploration or arrest
Authors: Moreau Hélène D. , Lemaître Fabrice , Garrod Kym R. , Garcia Zacarias , Lennon-Duménil Ana-Maria , Bousso Philippe 
Published: September 2015

Significance
To mount an efficient immune response, T cells need to recognize foreign antigen to become activated, proliferate, and acquire their effector functions. We show that T cells can adopt two behaviors depending on the strength of the antigen stimulation. Upon suboptimal stimulation, T cells adopt a scanning behavior that promotes local exploration of the microenvironment. Stronger stimulation triggers specific mechanisms that induce complete T-cell arrest. We propose that these distinct behaviors may represent an optimal strategy for T cells to find the strongest antigenic stimulation.
Lhx2 regulates the timing of β-catenin-dependent cortical neurogenesis
Authors: Hsu Lea Chia-Ling , Nam Sean , Cui Yi , Chang Ching-Pu , Wang Chia-Fang , Kuo Hung-Chih , Touboul Jonathan D. , Chou Shen-Ju 
Published: September 2015

Significance
The cerebral cortex is the most highly evolved structure in the human brain. Generating the correct number and types of neurons is crucial for brain function. We show a central role of the Lhx2 homeoprotein in this task: deleting Lhx2 in cortical progenitors leads to a temporal shift of neurogenesis initiation, resulting in a much smaller cortex with decreased numbers of neurons in all cortical layers. Further, we found that Lhx2 is required for the Wnt/β-catenin pathway to maintain progenitor proliferation. Using a parsimonious mathematical model, we demonstrated that such disruptions of neurogenesis timing are enough to explain the cortical size and thickness modifications observed. Our findings enlighten how neurogenesis timing is regulated molecularly and how it affects cortical size and organization.