bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation and amplification of radiative far field heat transfer: Towards a simple radiative thermal transistor
Authors: Joulain Karl , Ezzahri Younès , Drevillon Jérémie , Ben-Abdallah Philippe
Published: April 2015

We show in this article that phase change materials (PCM) exhibiting a phase transition between a dielectric state and a metallic state are good candidates to perform modulation as well as amplification of radiative thermal flux. We propose a simple situation in plane parallel geometry where a so-called radiative thermal transistor could be achieved. In this configuration, we put a PCM between two blackbodies at different temperatures. We show that the transistor effect can be achieved easily when this material has its critical temperature between the two blackbody temperatures. We also see that the more the material is reflective in the metallic state, the more switching effect is realized, whereas the more PCM transition is stiff in temperature, the more thermal amplification is high. We finally take the example of VO2 that exhibits an insulator-metallic transition at 68 °C. We show that a demonstrator of a radiative transistor could easily be achieved in view of the heat flux levels predicted. Far-field thermal radiation experiments are proposed to back the results presented.
Effects of the fluctuation in a singly-connected conducting filament structure on the distribution of the reset parameters in unipolar resistance switching
Authors: Na Sang-Chul , Lee Keundong , Chun Min Chul , Kwon Young-Sun , Shin Hye-Jin , Lee Sangik , Park Bae Ho , Kang Bo Soo
Published: April 2015

The reset current (Ireset), voltage (Vreset), and resistance of the low resistance state, as functions of the compliance current (CC), were investigated in a Pt/NiO/Pt structure that showed unipolar resistance switching. Interestingly, the Ireset and the Vreset measured at low CCs were found to be widely distributed. In order to explain the behavior of the reset parameters for the singly-connected conducting filament (CF) structure, a simple model of CFs was employed whose width variation follows the Gaussian distribution. The wide distribution of the reset parameters can be attributed to the fluctuation in the number and/or the width of the CFs.
Terahertz spectral change associated with glass transition of poly-ε-caprolactone
Authors: Komatsu Marina , Mizuno Maya , Saito Shingo , Fukunaga Kaori , Ohki Yoshimichi
Published: April 2015

We measured absorption spectra of unidirectionally stretched poly-ε-caprolactone (PCL) film in a range from 0.3 to 3.6 THz at temperatures from 10 to 300 K. Several absorption peaks were observed, when the electric field of THz waves was set in directions parallel and perpendicular to the stretching direction. The absorption bandwidths became significantly broad at around 200 K and above at least in two specific peaks. This temperature is close to the glass transition temperature of PCL. Further, it is shown by quantum chemical calculations that all the peaks obtained experimentally originate in skeletal vibrations of PCL. Therefore, it has become clear that a specific feature appears in the THz absorption spectrum of PCL associated with its glass transition.
Performance analysis of higher mode spoof surface plasmon polariton for terahertz sensing
Authors: Yao Haizi , Zhong Shuncong , Tu Wanli
Published: April 2015

We investigated the spoof surface plasmon polaritons (SSPPs) on 1D grooved metal surface for terahertz sensing of refractive index of the filling analyte through a prism-coupling attenuated total reflection setup. From the dispersion relation analysis and the finite element method-based simulation, we revealed that the dispersion curve of SSPP got suppressed as the filling refractive index increased, which cause the coupling resonance frequency redshifting in the reflection spectrum. The simulated results for testing various refractive indexes demonstrated that the incident angle of terahertz radiation has a great effect on the performance of sensing. Smaller incident angle will result in a higher sensitive sensing with a narrower detection range. In the meanwhile, the higher order mode SSPP-based sensing has a higher sensitivity with a narrower detection range. The maximum sensitivity is 2.57 THz/RIU for the second-order mode sensing at 45° internal incident angle. The proposed SSPP-based method has great potential for high sensitive terahertz sensing.
Enhanced single-cell printing by acoustophoretic cell focusing
Authors: Leibacher I. , Schoendube J. , Dual J. , Zengerle R. , Koltay P.
Published: April 2015

Recent years have witnessed a strong trend towards analysis of single-cells. To access and handle single-cells, many new tools are needed and have partly been developed. Here, we present an improved version of a single-cell printer which is able to deliver individual single cells and beads encapsulated in free-flying picoliter droplets at a single-bead efficiency of 96% and with a throughput of more than 10 beads per minute. By integration of acoustophoretic focusing, the cells could be focused in x and y direction. This way, the cells were lined-up in front of a 40 μm nozzle, where they were analyzed individually by an optical system prior to printing. In agreement with acoustic simulations, the focusing of 10 μm beads and Raji cells has been achieved with an efficiency of 99% (beads) and 86% (Raji cells) to a 40 μm wide center region in the 1 mm wide microfluidic channel. This enabled improved optical analysis and reduced bead losses. The loss of beads that ended up in the waste (because printing them as single beads arrangements could not be ensured) was reduced from 52% ± 6% to 28% ± 1%. The piezoelectric transducer employed for cell focusing could be positioned on an outer part of the device, which proves the acoustophoretic focusing to be versatile and adaptable.
Vacuum-ultraviolet photoreduction of graphene oxide: Electrical conductivity of entirely reduced single sheets and reduced micro line patterns
Authors: Tu Yudi , Ichii Takashi , Utsunomiya Toru , Sugimura Hiroyuki
Published: April 2015

We here report a scanning probe method to locally and directly research the electrical properties of vacuum-ultraviolet (VUV) reduced graphene oxide. The measured electrical conductivity of individual VUV-reduced GO (VUV-rGO) sheets by using conductive atomic force microscopy (CAFM) reached 0.20 S·m−1 after 64 min irradiation, which was clearly enhanced compared with the pristine GO. According to the X-ray photoelectron spectroscopy results, the recovered conductivity of VUV-rGO could be ascribed to the partial elimination of oxygen-containing functional groups and the rapid reconstruction of the C=C bonds. Heterogeneously distributed low- and high-conductivity domains (with a diameter of tens of nanometer to ca. 500 nm) were found from current mapping of the VUV-rGO sheet. By applying photomask lithography, rGO regions were drawn into single GO sheet and were researched by CAFM. The in-plane lateral conductivity of rGO regions increased obviously compared with pristine GO regions.
Electronic structure and magnetism in g-C4N3 controlled by strain engineering
Authors: Liu L. Z. , Wu X. L. , Liu X. X. , Chu Paul K.
Published: April 2015

Regulation of magnetism and half-metallicity has attracted much attention because of its potential in spintronics. The magnetic properties and electronic structure of graphitic carbon nitride (g-C4N3) with external strain are determined theoretically based on the density function theory and many-body perturbation theory (G0W0). Asymmetric deformation induced by uniaxial strain not only regulates the magnetic characteristics but also leads to a transformation from half-metallicity to metallicity. However, this transition cannot occur in the structure with symmetric deformation induced by biaxial strain. Our results suggest the use of strain engineering in metal-free spintronics applications.
Isothermal electric switching of magnetization in Cr2O3/Co thin film system
Authors: Ashida T. , Oida M. , Shimomura N. , Nozaki T. , Shibata T. , Sahashi M.
Published: April 2015

We investigated the magnetoelectric properties of Cr2O3/Co all-thin-film exchange coupling system with Cr spacer layer. In this system, significantly small coercivity (Hc < 50 Oe) was obtained by the Cr spacer layer insertion between Cr2O3 and Co layers. Owing to the small Hc, exchange bias field, Hex, larger than Hc was achieved. It enabled us to observe magnetization switching at a zero magnetic field, when Hex was reversed by magnetoelectric effect of Cr2O3 layer. Finally, we demonstrated the isothermal magnetoelectric switching of magnetization in the Cr2O3/Cr/Co all-thin-film system. By changing the direction of the electric field during the isothermal magnetoelectric switching process, both Hex and magnetization at a zero magnetic field were reversed back and forth, i.e., isothermal magnetization switching by an electric field was achieved.
Anisotropy of two-photon absorption and free-carrier effect in nonpolar GaN
Authors: Fang Yu , Zhou Feng , Yang Junyi , Wu Xingzhi , Xiao Zhengguo , Li Zhongguo , Song Yinglin
Published: April 2015

We reported a systematic study about the anisotropic optical nonlinearities in bulk m-plane and a-plane GaN crystals by Z-scan and pump-probe with phase object methods under picosecond at 532 nm. The two-photon absorption coefficient, which was measured as a function of polarization angle, exhibited oscillation curves with a period of π/2, indicating a highly polarized optical third-order nonlinearity in both nonpolar GaN samples. Furthermore, free-carrier absorption revealed stronger hole-related absorption for E⊥c than for E//c probe polarization. In contrast, free-carrier refraction was found almost isotropic due to electron-related refraction in the isotropic conduction bands.
Real-time sweat analysis via alternating current conductivity of artificial and human sweat
Authors: Liu Gengchen , Alomari Mahmoud , Sahin Bunyamin , Snelgrove Samuel E. , Edwards Jeffrey , Mellinger Axel , Kaya Tolga
Published: April 2015

Dehydration is one of the most profound physiological challenges that significantly affects athletes and soldiers if not detected early. Recently, a few groups have focused on dehydration detection using sweat as the main biomarker. Although there are some proposed devices, the electrical and chemical characteristics of sweat have yet to be incorporated into the validations. In this work, we have developed a simple test setup to analyze artificial sweat that is comprised the main components of human sweat. We provide theoretical and experimental details on the electrical and chemical behavior of the artificial sweat for various concentration values within a temperature range of 5 °C to 50 °C. We have also developed an efficient sweat collecting and detection system based on 3D printing. Human studies were conducted and this particular protocol has shown that dehydration starts to take effect as early as 40 min into the physical activity if there is no fluid intake during the exercise. We believe that our device will lead to developing viable real-time sweat analysis systems.
A review on the processing accuracy of two-photon polymerization
Authors: Zhou Xiaoqin , Hou Yihong , Lin Jieqiong
Published: April 2015

Two-photon polymerization (TPP) is a powerful and potential technology to fabricate true three-dimensional (3D) micro/nanostructures of various materials with subdiffraction-limit resolution. And it has been applied to microoptics, electronics, communications, biomedicine, microfluidic devices, MEMS and metamaterials. These applications, such as microoptics and photon crystals, put forward rigorous requirements on the processing accuracy of TPP, including the dimensional accuracy, shape accuracy and surface roughness and the processing accuracy influences their performance, even invalidate them. In order to fabricate precise 3D micro/nanostructures, the factors influencing the processing accuracy need to be considered comprehensively and systematically. In this paper, we review the basis of TPP micro/nanofabrication, including mechanism of TPP, experimental set-up for TPP and scaling laws of resolution of TPP. Then, we discuss the factors influencing the processing accuracy. Finally, we summarize the methods reported lately to improve the processing accuracy from improving the resolution and changing spatial arrangement of voxels.
The future of electron microscopy
Authors: Zhu Yimei , Dürr Hermann
Published: April 2015

Modern transmission electron microscopes can image individual atoms and molecules. But to unlock new science, the next generation of instruments must look beyond just higher spatial resolution.
The top quark, 20 years after its discovery
Authors: Denisov Dmitri , Vellidis Costas
Published: April 2015

The heaviest of nature’s elementary particles plays an outsized role in many fundamental processes. But because the top quark is so massive, it eluded experimental detection for nearly two decades.
Fiscal decentralization and internal conflict: an empirical investigation
Authors: Ezcurra Roberto
Published: April 2015

This paper examines the relationship between fiscal decentralization and internal conflict in seventy-seven countries during the period 1972–2000. The results show that the devolution of fiscal power to subnational tiers of government reduces the incidence of civil conflict. This finding is robust to the inclusion in the analysis of the degree of political decentralization and of a number of control variables commonly employed in the literature. Likewise, the observed relationship does not depend on the estimation strategy or the specific measures used to quantify the degree of fiscal decentralization and the incidence of civil conflicts within the various countries.
Metabolic indicators for retention of fetal membranes in Zebu and crossbred dairy cattle
Authors: Kumari Susavi , Prasad Shiv , Patbandha T. K. , Pathak R. , Kumaresan A. , Boro P. , Manimaran A. , Mohanty T. K.
Published: April 2015

The present study assessed the peripartum metabolic profile of Karan Fries crossbred (Holstein Friesian × Tharparkar) and Zebu (Sahiwal) cows in relation to expulsion of fetal membranes. Peripheral blood concentrations of glucose, total protein, total cholesterol, blood urea nitrogen, non-esterified fatty acid (NEFA) and β-hydroxy butyric acid (BHBA) were determined (from 30 days before and 2 days after calving) in cows that expelled fetal membranes normally (n = 13; 7 crossbred and 6 Zebu cows) and in cows that developed retention of fetal membranes (RFM; n = 13; 7 crossbred and 6 Zebu cows). In both breeds, the cows that developed RFM had significantly lower concentrations of cholesterol, glucose and total protein, while the concentrations of NEFA, BHBA and blood urea nitrogen were significantly (P < 0.05) higher than those in cows that normally expelled the fetal membranes. In crossbred cows affected with RFM, the concentrations of NEFA increased significantly (P < 0.05) from Day 14 prepartum to Day 2 postpartum and the concentrations of BHBA increased from Day 7 prepartum to Day 2 after calving. Similarly, in Zebu cows, NEFA and BHBA concentrations increased significantly (P < 0.05) between Day 5 prepartum and Day 2 postpartum in RFM cows. Using receiver operator characteristic analysis, we observed that the concentrations of NEFA and BHBA before calving were highly related to the RFM. It may be inferred that monitoring the levels of NEFA and BHBA during prepartum period would help in identifying the cows at the risk of developing RFM.
Simultaneous Observation of Triplet and Singlet Cyclopentane-1,3-diyl Diradicals in the Intersystem Crossing Process
Authors: Mizuno Takemi , Abe Manabu , Ikeda Noriaki
Published: April 2015

Intersystem crossing is an important chemical process. In this study, the rate constant of intersystem crossing, kISC ~3 × 107 s–1, for cyclopentane-1,3-diyl diradicals was unequivocally determined by the simultaneous observation of the decay process of the triplet diradical (λobs = 320 nm) and the growth process of the corresponding singlet diradical (λobs = 560 nm). The two spin states were directly observed using a long-lived singlet 2,2-dimethoxy-1,3-diphenylcyclopentane-1,3-diyl diradical.
Performance of spring cereal genotypes under defoliation on the Eyre Peninsula, South Australia
Authors: Latta R. A.
Published: April 2015

In mixed cropping and livestock dryland farming systems in southern Australia, grazing of cereals during their vegetative growth stages (typically during winter) can provide a valuable contribution of high-quality feed during a period of low pasture growth. This paper reports results from a series of experiments investigating the impact of defoliation on the grain production of cereals in the Eyre Peninsula region of South Australia. The comparative dry matter production and grain yield of wheat, barley and oats cultivars, with and without defoliation, at a range of growth stages were measured in four experiments over three growing seasons, two of which were water-deficient. The barley varieties evaluated produced up to twice the dry matter of the wheat or oats cultivars to the time of defoliation. Mowing following stem elongation more than halved grain yield (1.9 to 0.9 t ha–1) relative to no defoliation in an early-maturing variety, but with less reduction in later maturing varieties. Defoliation before stem elongation in two seasons of very low growing-season rainfall (<100 mm) caused no or very little loss in grain yields, which were generally <1 t ha–1. A long-season winter wheat produced similar grain yields irrespective of defoliation and timing, but with no yield advantage over the defoliated spring cereals. The results suggest opportunities to incorporate the grazing of cereals to fill a winter feed-gap in the low-rainfall zone of southern Australia.
Optimising grain yield and grazing potential of crops across Australia’s high-rainfall zone: a simulation analysis. 2. Canola
Authors: Lilley Julianne M. , Bell Lindsay W. , Kirkegaard John A.
Published: April 2015

Recent expansion of cropping into Australia’s high-rainfall zone (HRZ) has involved dual-purpose crops suited to long growing seasons that produce both forage and grain. Early adoption of dual-purpose cropping involved cereals; however, dual-purpose canola (Brassica napus) can provide grazing and grain and a break crop for cereals and grass-based pastures. Grain yield and grazing potential of canola (up until bud-visible stage) were simulated, using APSIM, for four canola cultivars at 13 locations across Australia’s HRZ over 50 years. The influence of sowing date (2-weekly sowing dates from early March to late June), nitrogen (N) availability at sowing (50, 150 and 250 kg N/ha), and crop density (20, 40, 60, 80 plants/m2) on forage and grain production was explored in a factorial combination with the four canola cultivars. The cultivars represented winter, winter × spring intermediate, slow spring, and fast spring cultivars, which differed in response to vernalisation and photoperiod.
Overall, there was significant potential for dual-purpose use of winter and winter × spring cultivars in all regions across Australia’s HRZ. Mean simulated potential yields exceeded 4.0 t/ha at most locations, with highest mean simulated grain yields (4.5–5.0 t/ha) in southern Victoria and lower yields (3.3–4.0 t/ha) in central and northern New South Wales. Winter cultivars sown early (March–mid-April) provided most forage (>2000 dry sheep equivalent (DSE) grazing days/ha) at most locations because of the extended vegetative stage linked to the high vernalisation requirement. At locations with Mediterranean climates, the low frequency (<30% of years) of early sowing opportunities before mid-April limited the utility of winter cultivars. Winter × spring cultivars (not yet commercially available), which have an intermediate phenology, had a longer, more reliable sowing window, high grazing potential (up to 1800 DSE-days/ha) and high grain-yield potential. Spring cultivars provided less, but had commercially useful grazing opportunities (300–700 DSE-days/ha) and similar yields to early-sown cultivars. Significant unrealised potential for dual-purpose canola crops of winter × spring and slow spring cultivars was suggested in the south-west of Western Australia, on the Northern Tablelands and Slopes of New South Wales and in southern Queensland. The simulations emphasised the importance of early sowing, adequate N supply and sowing density to maximise grazing potential from dual-purpose crops.
The influence of ignition technique on fire behaviour in spinifex open woodland in semiarid northern Australia
Authors: Williams Paul R. , Collins Eleanor M. , Blackman Mick , Blackman Clare , McLeod Jackie , Felderhof Leasie , Colless Lauren , Masters Kate , Coates Simon , Sturgess Andrew , Martin Graeme
Published: April 2015

Unplanned, unmanaged wildfires are a significant threat to people, infrastructure and ecosystems around the world. Managed, planned burning is widely used for reducing the incidence, extent or intensity of wildfires. Fire weather and the season of burning are recognised as crucial factors influencing fire behaviour but the demonstrated influence of ignition technique on fire behaviour is not as prominently discussed in relation to planned fires. We found wildfires, irrespective of season, burnt the ground layer more completely (i.e. were less patchy) and produced greater crown scorch severity than did planned fires in a spinifex (Triodia spp.)-dominated open woodland. Fires ignited with a 50-m line burning with the wind produced significantly higher intensities than did line ignition against the wind, and spot ignitions with or against the wind. These data suggest that the higher severity of wildfires in spinifex-dominated habitats is strongly influenced by long fire fronts, in addition to fire season and weather conditions. This study supports the value of planned burning for reducing fire severity and highlights the value of spot ignitions in ecological burning to create a patchily burnt landscape, with limited canopy severity.
Unraveling the association between mRNA expressions and mutant phenotypes in a genome-wide assessment of mice
Authors: Liao Ben-Yang , Weng Meng-Pin
Published: April 2015

Significance

The general perception that mRNA transcription of a gene is regulated by the functional requirements of the cell or tissue has never been systematically tested using genome-wide data. To assess the functional implications of mRNA transcription in mice directly, we analyzed gene expression data and phenotype data of mouse mutants as a proxy of gene function at the tissue level. Our results confirmed the important role transcriptional regulation has in maintaining the gene’s proper spatial and temporal functions. In addition, we found that mutations resulting in phenotypic defects in expressed tissues are more likely to occur in highly transcribed genes, tissue-specific genes, genes expressed during early embryonic stages, or genes with evolutionarily conserved mRNA expression.
Experimental ocean acidification alters the allocation of metabolic energy
Authors: Pan T.-C. Francis , Applebaum Scott L. , Manahan Donal T.
Published: April 2015

Significance

Anthropogenic emission of CO2is causing global ocean acidification. For many species, biological responses to acidification often show limited impact at the level of the whole animal. Our integrative studies of whole-organism growth and metabolic rates, rates of protein synthesis and ion transport, enzyme activity, and gene expression show that although the organismal-level impact of acidification on developing sea urchins was minimal, dramatic compensation occurred at the cellular level. Increased rates of synthesis and ion transport resulted in 84% of available energy being allocated to those processes under acidification. Defining the limits of differential energy allocation for the maintenance of critical physiological functions in response to compounding stressors will help provide a mechanistic understanding of resilience potential to environmental change.
RoR2 functions as a noncanonical Wnt receptor that regulates NMDAR-mediated synaptic transmission
Authors: Cerpa Waldo , Latorre-Esteves Elena , Barria Andres
Published: April 2015

Significance

NMDA receptors (NMDARs) are key components of excitatory synapses. Here we report that Wnt signaling via activation of tyrosine kinase-like orphan receptor 2 can regulate synaptic NMDARs. Understanding what controls number and subunit composition is central to understand neuropathologies associated with dysfunction of synaptic NMDARs, including Alzheimer’s disease and schizophrenia. Our data indicate a previously unidentified role for Wnt signaling in the regulation of established synaptic connections and provides a mechanism for Wnt ligands to modulate basal synaptic transmission, synaptic plasticity, and brain functions acutely.
Response of seafloor ecosystems to abrupt global climate change
Authors: Moffitt Sarah E. , Hill Tessa M. , Roopnarine Peter D. , Kennett James P.
Published: April 2015

Significance

This investigation presents the first record to our knowledge of the disturbance and recovery of seafloor ecosystem biodiversity in response to abrupt climate change. Ocean sediments have been extensively studied using geochemical and microfaunal (e.g., Foraminifera) analyses; however, these traditional approaches produce limited interpretations of ecological and community-scale responses. We demonstrate here that ocean sediments harbor metazoan fossil material that can be used to reconstruct the response of seafloor biodiversity to global-scale climate events. We show that the last deglaciation, the most recent episode of climate warming, was accompanied by abrupt reorganizations of continental margin seafloor ecosystems through expansions and contractions of the subsurface low-oxygen zones. This archive reveals that global climate change disturbs seafloor ecosystems on continental margins and commits them to millennia of ecological recovery.
Whole-genome sequencing is more powerful than whole-exome sequencing for detecting exome variants
Authors: Belkadi Aziz , Bolze Alexandre , Itan Yuval , Cobat Aurélie , Vincent Quentin B. , Antipenko Alexander , Shang Lei , Boisson Bertrand , Casanova Jean-Laurent , Abel Laurent
Published: April 2015

Significance

Whole-exome sequencing (WES) is gradually being optimized to identify mutations in increasing proportions of the protein-coding exome, but whole-genome sequencing (WGS) is becoming an attractive alternative. WGS is currently more expensive than WES, but its cost should decrease more rapidly than that of WES. We compared WES and WGS on six unrelated individuals. The distribution of quality parameters for single-nucleotide variants (SNVs) and insertions/deletions (indels) was more uniform for WGS than for WES. The vast majority of SNVs and indels were identified by both techniques, but an estimated 650 high-quality coding SNVs (∼3% of coding variants) were detected by WGS and missed by WES. WGS is therefore slightly more efficient than WES for detecting mutations in the targeted exome.
Amplitude of the actomyosin power stroke depends strongly on the isoform of the myosin essential light chain
Authors: Guhathakurta Piyali , Prochniewicz Ewa , Thomas David D.
Published: April 2015

Significance

Myosin is an enzyme that uses energy from ATP to exert force on another protein, actin, resulting in muscle contraction. Force is generated in the power stroke, when the actin–myosin complex transitions from a weak-binding structure (ATP bound to myosin) to a strong-binding structure (ADP). We detected the amplitude of the power stroke directly by measuring fluorescence resonance energy transfer from actin to myosin, with high time resolution following excitation with a pulsed laser. We found that the amplitude of the power stroke is strongly dependent on the form of the essential light chain that is bound to myosin. This provides a structural explanation for previous functional observations, with implications for muscle pathophysiology and therapeutic design.
Autoinhibition of MDMX by intramolecular p53 mimicry
Authors: Chen Lihong , Borcherds Wade , Wu Shaofang , Becker Andreas , Schonbrunn Ernst , Daughdrill Gary W. , Chen Jiandong
Published: April 2015

Significance

MDMX protein is a critical regulator of p53 and a novel drug target. The current generation of MDM2 inhibitors does not inhibit MDMX. Therefore, their therapeutic efficacy will be influenced by poorly characterized MDMX functional status in tumors. Efforts to develop MDMX inhibitors have been largely unsuccessful, indicating gaps in our understanding of the structure and regulation of MDMX. This study provides evidence that MDMX-p53 binding is regulated by an autoinhibitory mechanism that involves intramolecular interaction in MDMX through p53 mimicry. The results suggest a mechanism by which DNA damage signaling inhibits MDMX and activates p53.
Zinc as chaperone-mimicking agent for retardation of amyloid β peptide fibril formation
Authors: Abelein Axel , Gräslund Astrid , Danielsson Jens
Published: April 2015

Significance

One histologic hallmark of Alzheimer’s disease is the self-assembly of amyloid β peptide (Aβ) into insoluble amyloid aggregates. This aggregation process is strongly dependent on environmental conditions and metal ions, such as zinc, have been shown to modulate Aβ aggregation. To understand the underlying molecular mechanism of how zinc affects fibril formation we analyzed the aggregation kinetics and could conclude that zinc causes a significant reduction in elongation rate (i.e., monomer addition to the fibril ends). We used NMR methods to elucidate the details of zinc binding and we found that the N terminus of Aβ transiently folds around the zinc ion, forming a metastable dynamic complex.
Characterization of global loss of imprinting in fetal overgrowth syndrome induced by assisted reproduction
Authors: Chen Zhiyuan , Hagen Darren E. , Elsik Christine G. , Ji Tieming , Morris Collin James , Moon Laura Emily , Rivera Rocío Melissa
Published: April 2015

Significance

Large offspring syndrome (LOS) is a fetal overgrowth condition that mimics the human syndrome Beckwith–Wiedemann. These conditions have been observed with higher incidence in offspring conceived with the use of assisted reproductive technologies and are believed to be the result of misregulation of a set of genes that are expressed only from the maternally or paternally inherited chromosomes. These genes are known as imprinted genes. In our study, we demonstrate that the kidney, brain, muscle, and liver of LOS fetuses show misregulation of multiple imprinted genes when compared with controls. Furthermore, we show that the magnitude of overgrowth in LOS fetuses correlates with the number of misregulated imprinted genes. Our results may help create diagnostics for these fetal syndromes.
αIIbβ3 variants defined by next-generation sequencing: Predicting variants likely to cause Glanzmann thrombasthenia
Authors: Buitrago Lorena , Rendon Augusto , Liang Yupu , Simeoni Ilenia , Negri Ana ,   ThromboGenomics Consortium, Filizola Marta , Ouwehand Willem H. , Coller Barry S. , Alessi Marie-Christine , Ballmaier Matthias , Bariana Tadbir , Bellissimo Daniel , Bertoli Marta , Bray Paul , Bury Loredana , Carrell Robin , Cattaneo Marco , Collins Peter , French Deborah , Favier Remi , Freson Kathleen , Furie Bruce , Germeshausen Manuela , Ghevaert Cedric , Gomez Keith , Goodeve Anne , Gresele Paolo , Guerrero Jose , Hampshire Dan J. , Hadinnapola Charaka , Heemskerk Johan , Henskens Yvonne , Hill Marian , Hogg Nancy , Johnsen Jill , Kahr Walter , Kerr Ron , Kunishima Shinji , Laffan Michael , Natwani Amit , Neerman-Arbez Marguerite , Nurden Paquita , Nurden Alan , Ormiston Mark , Othman Maha , Ouwehand Willem , Perry David , Vilk Shoshana Ravel , Reitsma Pieter , Rondina Matthew , Simeoni Ilenia , Smethurst Peter , Stephens Jonathan , Stevenson William , Szkotak Artur , Turro Ernest , Van Geet Christel , Vries Minka , Ward June , Waye John , Westbury Sarah , Whiteheart Sidney , Wilcox David , Zhang Bi
Published: April 2015

Significance

Next-generation sequencing is identifying millions of novel gene variants, presenting challenges to researchers and clinicians. Variations in the genes
ITGA2B
and
ITGB3
affect integrin αIIbβ3, leading to the bleeding disorder Glanzmann thrombasthenia. We analyzed novel missense variants on ∼32,000 alleles of
ITGA2B
and
ITGB3
and found missense variants affecting ∼10% of the amino acids in each protein in ∼1.3% of the population. Almost all variants are rare, indicating recent entry into the population. Two novel variants we predicted would be deleterious profoundly affected recombinant protein expression. At cut-off values that correctly predicted at least 69% of the known Glanzmann thrombasthenia mutations as deleterious, three variant prediction algorithms predicted that at least 27% of the novel variants are deleterious.
Amygdala lesions do not compromise the cortical network for false-belief reasoning
Authors: Spunt Robert P. , Elison Jed T. , Dufour Nicholas , Hurlemann René , Saxe Rebecca , Adolphs Ralph
Published: April 2015

Significance

Humans use a so-called “theory-of-mind” to reason about the beliefs of others. Neuroimaging studies of belief reasoning suggest it activates a specific cortical network. The amygdala is interconnected with this network and plays a fundamental role in social behavior. For the first time, to our knowledge, we test whether amygdala lesions compromise the cortical implementation of theory-of-mind. Two patients with bilateral amygdala lesions performed a belief reasoning test while undergoing functional MRI. Remarkably, both patients showed typical test performance and cortical activity when compared with nearly 500 healthy controls. This result shows that the amygdala is not a necessary part of theory-of-mind function in adulthood and forces a reevaluation of the amygdala’s role in social cognition.
Multiple mechanisms limit meiotic crossovers: TOP3α and two BLM homologs antagonize crossovers in parallel to FANCM
Authors: Séguéla-Arnaud Mathilde , Crismani Wayne , Larchevêque Cécile , Mazel Julien , Froger Nicole , Choinard Sandrine , Lemhemdi Afef , Macaisne Nicolas , Van Leene Jelle , Gevaert Kris , De Jaeger Geert , Chelysheva Liudmilla , Mercier Raphael
Published: April 2015

Significance

During meiosis, crossovers (COs) reshuffle homologous chromosomes, generating genetic diversity on which natural or human selection can act. However, CO numbers typically are very low, raising questions about the evolutionary forces that impose this constraint and limiting the efficiency of breeding programs. Here, we identified anti-CO factors in
Arabidopsis
and showed that several mechanisms actively antagonize CO formation in parallel. Disrupting these anti-CO factors provokes a large increase in CO frequency without affecting meiotic progression. These results suggest that COs are restrained not because a high number would impair chromosome segregation but because excessive recombination could break favorable genetic combinations built by past selection. These findings hold great promise for improving the efficiency of plant breeding programs.
Reconstitution of a prokaryotic minus end-tracking system using TubRC centromeric complexes and tubulin-like protein TubZ filaments
Authors: Fink Gero , Löwe Jan
Published: April 2015

Significance

Bacteria carry large extrachromosomal circular DNA molecules, called plasmids, that contain specific genes causing virulence and drug resistance. An active molecular machine based on actin- or tubulin-like filaments ensures proper inheritance of these low-copy-number plasmids. Tubulin-like filaments are involved in the maintenance of virulence plasmids in pathogens such as
Bacillus thuringiensis
,
Bacillus anthraxis
, and
Bacillus cereus
. We discovered that filaments of tubulin-like TubZ protein and TubRC centromeric complexes, containing TubR protein and
tubC
DNA, encoded on plasmid pBtoxis, self-assemble into a prokaryotic minus end-tracking system. Filament depolymerization and processive TubRC binding to shrinking minus ends cause directed DNA motility, most likely through pulling forces.
Quantitative analysis of vesicle recycling at the calyx of Held synapse
Authors: Qiu Xufeng , Zhu Qianwen , Sun Jianyuan
Published: April 2015

Significance

Compared with vesicle exocytosis and endocytosis, relatively little is known about vesicle recycling. Here, we developed a novel methodological approach, potentially applicable to all axosomatic synapses, to quantify the kinetics of vesicle recycling with exquisite signal and temporal resolution. Using this approach combined with electron-microscopic observations, we estimated that ∼80% of synaptic vesicles participate in recycling and provided an explanation to reconcile the discrepancies in previous reports. We kinetically dissected vesicle recycling in the calyceal terminal, defined a new concept of the readily priming pool, and proposed a realistic kinetic model to quantify the basic properties of vesicle recycling. These findings contribute to filling the gap in understanding vesicle recycling, particularly postendocytotic vesicle trafficking.
CD14-expressing cancer cells establish the inflammatory and proliferative tumor microenvironment in bladder cancer
Authors: Cheah Ming T. , Chen James Y. , Sahoo Debashis , Contreras-Trujillo Humberto , Volkmer Anne K. , Scheeren Ferenc A. , Volkmer Jens-Peter , Weissman Irving L.
Published: April 2015

Significance

Our study defines the crucial role of CD14-high bladder cancer (BC) cells in orchestrating multiple hallmarks of cancer in the early stages of BC. Inflammatory factors produced by this subpopulation of tumor cells activate angiogenesis to support establishment and maintenance of an immune-suppressive, inflammatory tumor microenvironment. Additionally, this subpopulation is able to drive tumor growth by producing factors that drive autocrine and paracrine proliferative stimulation. Here we show that a tumor-cell subpopulation establishes a tumor microenvironment orchestrating tumor-promoting inflammation and tumor-cell proliferation. Collectively, this study highlights the need to explore the broader role of CD14-expressing neoplastic cells in other solid tumors. It is noteworthy that CD14 expression is critical for IL6 secretion by these cells. Therefore, therapeutic targeting of CD14 might represent a strategy for treating cancer.
Four hundred million years of silica biomineralization in land plants
Authors: Trembath-Reichert Elizabeth , Wilson Jonathan Paul , McGlynn Shawn E. , Fischer Woodward W.
Published: April 2015

Significance

Amorphous silica (SiO
2
) phases produced by plants are principal mass fluxes in the global silica cycle. The study of silica biomineralization in plants has largely focused on angiosperms, leaving open questions about its early evolution. To address the effect of early plants on the silica cycle, we measured the silica contents of extant members of plant groups known from fossils to have been major components of the terrestrial landscape in the past, as grasses are today. Most of these early-diverging plant lineages accumulate substantial amounts of silica. We compared these observations with the distribution and evolution of plant silica transport proteins, suggesting convergent evolution of silica use. Results presented here outline an extensive evolutionary history of silica biomineralization in plants.
Linked topological colloids in a nematic host
Authors: Martinez Angel , Hermosillo Leonardo , Tasinkevych Mykola , Smalyukh Ivan I.
Published: April 2015

Significance

Colloidal dispersions are abundant in nature, fundamental science, and technology, with examples ranging from fog and milk to colloidal models of atomic crystals and glasses and colloidal quantum dots used in fabricating the third-generation solar cells. Despite the recent progress in exquisite control of geometric shape and topology of constituent colloidal particles, thus far only single-component colloidal building blocks have been fabricated or found occurring in nature. We develop multicomponent linked colloidal particles lacking connectivity of their surfaces, with each component behaving as a genus-one colloidal particle itself but being topologically linked with the other components within a colloidal building block. We uncover topological property-defining behavior of such colloidal particles when dispersed in a nematic liquid crystal medium.
Large-scale recoding of an arbovirus genome to rebalance its insect versus mammalian preference
Authors: Shen Sam H. , Stauft Charles B. , Gorbatsevych Oleksandr , Song Yutong , Ward Charles B. , Yurovsky Alisa , Mueller Steffen , Futcher Bruce , Wimmer Eckard
Published: April 2015

Significance

Arboviruses (arthropod-borne viruses), a large group of RNA viruses, replicate in insects that transmit them to mammals, their second host. Insects and mammals have evolved different protein encoding strategies (codon pair bias); hence, arboviruses must delicately balance their encodings between two phyla. Using dengue virus (DENV), the most important human arbovirus pathogen, as a model, we have, by computer design and chemical synthesis, undone this balance in codon pair bias in favor of insects. Recoded DENVs grow well in insect cells but are highly attenuated in mammalian cells and in suckling mice. This unique approach offers a previously unidentified possibility to rapidly develop new vaccine candidates against DENV and perhaps against many different human arboviruses.
Candidate ionotropic taste receptors in the
Drosophila
larva
Authors: Stewart Shannon , Koh Tong-Wey , Ghosh Arpan C. , Carlson John R.
Published: April 2015

Significance

The coding of taste is based on the activity of taste receptors. We examine in
Drosophila
the expression of a group of ∼35 ionotropic receptors (IRs), the IR20a clade, about which remarkably little is known. We find evidence that 11 are expressed in the larva. Most are expressed in neurons of the pharynx, a taste organ. Others are expressed in body-wall neurons that may be chemosensory. The organization of
IR
gene expression differs from the organization of expression of
Gustatory receptor
taste receptor genes. Among neurons expressing IR20a receptors in the pharynx, two projection patterns in the CNS can be distinguished, perhaps representing cues with different valence. Our results suggest that the IR20a clade encodes a class of larval taste receptors.
Lag threads organize the brain’s intrinsic activity
Authors: Mitra Anish , Snyder Abraham Z. , Blazey Tyler , Raichle Marcus E.
Published: April 2015

Significance

It is well known that slow intrinsic activity, as measured by resting-state fMRI in a variety of animals including humans, is organized into temporally synchronous networks. The question of whether intrinsic activity contains reproducible temporal sequences has received far less attention. We have previously shown that human resting-state fMRI contains a highly reproducible lag structure. Here, we demonstrate that this lag structure is of high dimensionality and consists of multiple highly reproducible temporal sequences, which we term “lag threads.” Moreover, we demonstrate that the well-known zero-lag temporal correlation structure of intrinsic activity emerges as a consequence of lag structure. Thus, lag threads may represent a fundamental and previously unsuspected level of organization in resting-state activity.
RING E3 mechanism for ubiquitin ligation to a disordered substrate visualized for human anaphase-promoting complex
Authors: Brown Nicholas G. , VanderLinden Ryan , Watson Edmond R. , Qiao Renping , Grace Christy R. R. , Yamaguchi Masaya , Weissmann Florian , Frye Jeremiah J. , Dube Prakash , Ei Cho Shein , Actis Marcelo L. , Rodrigues Patrick , Fujii Naoaki , Peters Jan-Michael , Stark Holger , Schulman Brenda A.
Published: April 2015

Significance

The anaphase-promoting complex/cyclosome (APC) is a multisubunit RING E3 ubiquitin (Ub) ligase that regulates mitosis, meiosis, and numerous facets of neurobiology by targeting key regulatory proteins for Ub-mediated degradation. Despite great importance, it remains unclear how APC, or most of the other 600 RING E3s in humans, targets Ub to lysines in disordered substrates. Here, we report the structural and molecular basis for substrate ubiquitination by APC and its partner E2, UBCH10. UBCH10 is recruited to APC, activated for ubiquitination, and positioned for substrate targeting through multisite interactions with the APC cullin–RING core. We propose that many RING E3–E2 assemblies work similarly, with multisite interactions establishing specificity, harnessing ubiquitination machineries to accelerate searching for target lysines, and facilitating regulation.
Cis and trans interactions between atlastin molecules during membrane fusion
Authors: Liu Tina Y. , Bian Xin , Romano Fabian B. , Shemesh Tom , Rapoport Tom A. , Hu Junjie
Published: April 2015

Significance

The membrane-anchored GTPase atlastin (ATL) mediates the fusion of endoplasmic reticulum membranes into a network of tubules and sheets, but the mechanism of ATL function is still poorly understood. Here we show that vesicle fusion is preceded by GTP hydrolysis-dependent tethering, caused by the interaction of ATL molecules in opposing membranes. GTP hydrolysis also dissociates ATL dimers sitting in the same membrane (cis dimers), generating a pool of ATL monomers that can dimerize with molecules on a different (trans) membrane. Multiple rounds of GTP hydrolysis and the cooperation of several ATL molecules in each membrane are required for a successful fusion event. These results lead to a model of ATL-mediated fusion that also may have implications for SNARE-mediated fusion.
The circadian oscillator in
Synechococcus elongatus
controls metabolite partitioning during diurnal growth
Authors: Diamond Spencer , Jun Darae , Rubin Benjamin E. , Golden Susan S.
Published: April 2015

Significance

Cyanobacteria are increasingly being considered for use in large-scale outdoor production of fuels and industrial chemicals. Cyanobacteria can anticipate daily changes in light availability using an internal circadian clock and rapidly alter their metabolic processes in response to changes light availability. Understanding how signals from the internal circadian clock and external light availability are integrated to control metabolic shifts will be important for engineering cyanobacteria for production in natural outdoor environments. This study has assessed how “knowing” the correct time of day, via the circadian clock, affects metabolic changes when a cyanobacterium goes through a dark-to-light transition. Our data show that the circadian clock plays an important role in inhibiting activation of the oxidative pentose phosphate pathway in the morning.
Clustering of mammalian
Hox
genes with other H3K27me3 targets within an active nuclear domain
Authors: Vieux-Rochas Maxence , Fabre Pierre J. , Leleu Marion , Duboule Denis , Noordermeer Daan
Published: April 2015

Significance

The development of an embryo from a single fertilized cell is orchestrated by a large set of key regulatory genes whose activities need to be precisely controlled. Proteins from the Polycomb group (PcG) family maintain the inactive state of these genes by modifying the surrounding histone H3 tails. Here we report that these inactive genes contact other PcG-rich regions within otherwise active environments in the cell nucleus, suggesting the presence of repressive microenvironments. PcG positive genes interact independently from neighboring genes, depending on their linear distance and more global chromosome folding characteristics, with only moderate changes during embryonic development.
The partial 𝐶⁰-estimate along the continuity method
Authors: Székelyhidi Gábor
Published: April 2015

We prove that the partial

C
0

C^0

-estimate holds for metrics along Aubin’s continuity method for finding Kähler-Einstein metrics, confirming a special case of a conjecture due to Tian. We use the method developed in recent work of Chen-Donaldson-Sun on the analogous problem for conical Kähler-Einstein metrics.