bluuebunny/crossref_metadata_2025 huggingface dataset:
Manipulation of carrier concentration, crystallite size and density in polycrystalline anatase TiO2via amorphous-phase medium range atomic order
Authors: Eitan Barlaz D. , Seebauer Edmund G.
Published: February 2015

Deposition temperature and other growth conditions affect carrier concentration and other properties of thin-film polycrystalline anatase, yielding evidence for medium range atomic order in the initially amorphous films.
Syntheses and structures of two gold(i) coordination compounds derived from P–S hybrid ligands and their efficient catalytic performance in the photodegradation of nitroaromatics in water
Authors: Qi Hai-Xiao , Wang Jian-Feng , Ren Zhi-Gang , Ning Jin-Jiao , Lang Jian-Ping
Published: February 2015

Two Au–P–S complexes [Au2(dppatc)2]Cl2 and [Au(dppmt)]2 were prepared and they showed high catalytic activity toward the photodegradation of nitroaromatics in water.
The total synthesis of (−)-cryptocaryol A
Authors: Dias L. C. , Kuroishi P. K. , de Lucca E. C.
Published: February 2015

A stereoselective total synthesis of (−)-cryptocaryol A (1) is described. Key features of the 17-step route include the use of three boron-mediated aldol reaction–reduction sequences to control all stereocenters and an Ando modification of the Horner–Wadsworth–Emmons olefination that permitted the installation of the Z double bond of the α-pyrone ring.
Non-monotonous dependence of the electrical conductivity and chemical stability of a graphene freestanding film on the degree of reduction
Authors: Jo Yun Kyung , Kim In Young , Kim Su-jin , Shin Su In , Go Ara , Lee Youngmi , Hwang Seong-Ju
Published: February 2015

The controlled oxygenation of rG-O nanosheets is quite effective in controlling the chemical bonding nature and surface morphology of the graphene films and also in optimizing their electrical conductivity and stability.
N,N-Diarylamino end-capping as a new strategy for simultaneously enhancing open-circuit voltage, short-circuit current density and fill factor in small molecule organic solar cells
Authors: Yang Daobin , Zhu Youqin , Jiao Yan , Yang Lin , Yang Qianqian , Luo Qian , Pu Xuemei , Huang Yan , Zhao Suling , Lu Zhiyun
Published: February 2015

N,N-Diarylamino end-capping strategy for asymmetrical squaraines with simultaneously enhancedVoc,Jscand FF in solution-processed small molecule organic solar cells.
Copper doped ceria porous nanostructures towards a highly efficient bifunctional catalyst for carbon monoxide and nitric oxide elimination
Authors: Li Shanlong , Wang Nengli , Yue Yonghai , Wang Guangsheng , Zu Zhao , Zhang Yu
Published: February 2015

Cu2+doped CeO2porous nanomaterials were synthesized by calcining CeCu–MOF nanocrystals. They exhibited a superior bifunctional catalytic performance for CO oxidation and selective catalytic reduction of NO.
Correction: Tailor-made gemcitabine prodrug nanoparticles from well-defined drug–polymer amphiphiles prepared by controlled living radical polymerization for cancer chemotherapy
Authors: Wang Weiwei , Li Chen , Zhang Ju , Dong Anjie , Kong Deling
Published: February 2015

Correction for ‘Tailor-made gemcitabine prodrug nanoparticles from well-defined drug–polymer amphiphiles prepared by controlled living radical polymerization for cancer chemotherapy’ by Weiwei Wang et al., J. Mater. Chem. B, 2014, 2, 1891–1901.
The substituent group effect on the morphology and memory performance of phenazine derivatives
Authors: Gu Pei-Yang , Ma Yong , He Jing-Hui , Long Guankui , Wang Chengyuan , Chen Wangqiao , Liu Yi , Xu Qing-Feng , Lu Jian-Mei , Zhang Qichun
Published: February 2015

The memory devices based on ITO/2OHPz/Al exhibited excellent ternary memory behavior while devices based on ITO/1OHPz/Al displayed binary memory behavior.
Enhancing Engagement in the Classroom for Students with ASD
Authors: Steinbrenner Jessica Dykstra
Published: February 2015

Engagement is important for development and learning, and an area of need for children with autism spectrum disorder (ASD). Experts recommend that children with ASD should be actively engaged for at least 25 hours per week in effective interventions (National Research Council [NRC], 2001). There is a growing body of evidence-based practices and strategies that can be used in classroom settings to support the engagement of students with ASD, including instructional arrangements, instructional strategies, and adult interaction behaviors. This article will provide a summary of evidence-based practices that can be used with students with ASD in school settings.
Fourier‐Bessel transform and time–frequency‐based approach for detecting manoeuvring air target in sea‐clutter
Authors: Suresh Penamati , Thayaparan Thayananthan , Venkataramaniah Kamisetti
Published: February 2015

In many applications, it may be desired to decompose a non‐stationary signal into its individual components. If spectral components of the non‐stationary signal do not overlap in the frequency domain then Fourier transform can be used to decompose the non‐stationary signal. Fourier transform fails to decompose the non‐stationary signal if its spectral components overlap in the frequency domain. In this study, the authors propose Fourier‐Bessel transform and the time–frequency analysis in conjunction with the fractional Fourier transform (FB‐TF) method for the separation of multi‐component non‐stationary signal whose components overlap in both time and/or frequency domains. The efficiency of the proposed method is compared with one of the traditional decomposition methods like EMD. The proposed approach is applied to both simulated and experimental radar data. Results demonstrate the effectiveness of the proposed method for non‐stationary signal separation and for detecting manoeuvring target in heavy sea‐clutter environments. The improvement factor and clutter attenuation are calculated and used to compare the performance of the EMD and the FB‐TF methods in suppressing the sea‐clutter and enhancing target detection. The proposed method can be used as a potential tool for detecting and enhancing the low observable manoeuvring air targets in the sea‐clutter environment.
Weak target detection in sea clutter background using local‐multifractal spectrum with adaptive window length
Authors: Fan Yifei , Luo Feng , Li Ming , Hu Chong , Chen Shuailin
Published: February 2015

Weak target detection based on fractal analysis is a hot research topic. The existing methods, using single fractal dimension and Hurst exponent, are not applicable under low signal clutter ratio (SCR) conditions. This study focuses on enhancing the performance of weak target detection by utilising the multifractal properties of sea clutter. The existing global multifractal spectrum based method has limited performance because of its non‐stability. Therefore this study proposes a weak target detection method by taking into account the local difference of multifractal spectrum between sea clutter with and without target. The local‐multifractal spectrum is obtained by adding a rectangle window to the multifractal spectrum, and the local difference is calculated by the local mean square summation algorithm. In addition, the window length, a key parameter for obtaining the local‐multifractal spectrum, is adaptively computed by the slope of the singularity intensity. In comparison with the existing multifractal spectrum based method, the experimental results of real S‐band and X‐band sea clutter data show that the proposed method is more stable, and could achieve a better detection performance under low SCR conditions.
Impact of annealing temperature on the mechanical and electrical properties of sputtered aluminum nitride thin films
Authors: Gillinger M. , Schneider M. , Bittner A. , Nicolay P. , Schmid U.
Published: February 2015

Aluminium nitride (AlN) is a promising material for challenging sensor applications such as process monitoring in harsh environments (e.g., turbine exhaust), due to its piezoelectric properties, its high temperature stability and good thermal match to silicon. Basically, the operational temperature of piezoelectric materials is limited by the increase of the leakage current as well as by enhanced diffusion effects in the material at elevated temperatures. This work focuses on the characterization of aluminum nitride thin films after post deposition annealings up to temperatures of 1000 °C in harsh environments. For this purpose, thin film samples were temperature loaded for 2 h in pure nitrogen and oxygen gas atmospheres and characterized with respect to the film stress and the leakage current behaviour. The X-ray diffraction results show that AlN thin films are chemically stable in oxygen atmospheres for 2 h at annealing temperatures of up to 900 °C. At 1000 °C, a 100 nm thick AlN layer oxidizes completely. For nitrogen, the layer is stable up to 1000 °C. The activation energy of the samples was determined from leakage current measurements at different sample temperatures, in the range between 25 and 300 °C. Up to an annealing temperature of 700 °C, the leakage current in the thin film is dominated by Poole-Frenkel behavior, while at higher annealing temperatures, a mixture of different leakage current mechanisms is observed.
Characterization of bismuth nanospheres deposited by plasma focus device
Authors: Ahmad M. , Al-Hawat Sh. , Akel M. , Mrad O.
Published: February 2015

A new method for producing thin layer of bismuth nanospheres based on the use of low energy plasma focus device is demonstrated. Various techniques such as scanning electron microscopy, Rutherford backscattering spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been used to characterize the morphology and the composition of the nanospheres. Experimental parameters may be adjusted to favour the formation of bismuth nanospheres instead of microspheres. Therefore, the formation of large surface of homogeneous layer of bismuth nanospheres with sizes of below 100 nm can be obtained. The natural snowball phenomenon is observed to be reproduced in nanoscale where spheres roll over the small nanospheres and grow up to bigger sizes that can reach micro dimensions. The comet-like structure, a reverse phenomenon to snowball is also observed.
An elastic-support model for enhanced bistable piezoelectric energy harvesting from random vibrations
Authors: Leng Y. G. , Gao Y. J. , Tan D. , Fan S. B. , Lai Z. H.
Published: February 2015

To overcome the defect of conventional nonlinear piezoelectric cantilever vibration energy harvesters, in this paper we conceive an elastic-support model to study the performance of energy converters under two types of variable-intensity excitation conditions: filtered Gaussian noises and pink noises. When excitation intensity is insufficient, thanks to the system's variable potential function, frequent bistable transition oscillations between two wells occur in elastic-support systems, while only weak oscillations in either well could be observed in rigid-support systems. In practical applications, the structural parameters of energy harvesters are not allowed to make real-time changes. If considered remaining the magnet interval and the spring's elastic stiffness unchanged while receiving stable maximum output voltage, elastic-support systems can be made full use toward variable-intensity filtered Gaussian noises. It has been proven that elastic-support systems are capable of adapting to random excitations with variable intensity, through which maximum power output and sufficient electromechanical energy conversion of the system can be accomplished.
Phase diagram and magnetocaloric effects in Ni1-xCrxMnGe1.05
Authors: Aryal Anil , Quetz Abdiel , Pandey Sudip , Eubank Michael , Samanta Tapas , Dubenko Igor , Stadler Shane , Ali Naushad
Published: February 2015

The structural and magnetic properties of the Ni1−xCrxMnGe1.05 system (for x = 0, 0.035, 0.070, 0.105) have been studied by x-ray diffraction (XRD), differential scanning calorimetry (DSC), and magnetization measurements. A change in crystal structure from orthorhombic to hexagonal was observed in the XRD data at chromium concentrations of x = 0.035, 0.070, and 0.105. The values of the cell parameters and volume of the unit cell for orthorhombic and hexagonal phase were determined. It was found that the partial substitution of Cr for Ni in Ni1−xCrxMnGe1.05 results in a first order magnetostructural transition from antiferromagnetic to ferromagnetic (FM) at TM = 132 K for x = 0.105. A FM to paramagnetic second order transition has been observed at TC = 204 K. A magnetic entropy change of |ΔSM| = 4.5 J/kg K for ΔH = 5 T was observed in the vicinity of TC and TM for x = 0.105. The values of the latent heat (L = 2.2 J/g) and corresponding total entropy changes (ΔST = 16 J/kg K) have been determined from DSC measurements. A concentration-dependent phase diagram of transition temperatures has been constructed using the magnetic and DSC data.
Single-phase quaternary MgxZn1−xO1−ySy alloy thin films grown by pulsed laser deposition
Authors: He Yunbin , Cheng Hailing , Tai Jiali , Li Lei , Zhang Lei , Li Mingkai , Lu Yinmei , Zhang Wei , Meyer Bruno K.
Published: February 2015

Quaternary-alloy MgxZn1−xO1−ySy thin films were grown quasi-epitaxially on c-plane sapphire substrates by pulsed laser deposition. Single-phase wurtzite MgxZn1−xO1−ySy films with compositions of 0.07 < x < 0.21 and y ≥ 0.8 were achieved using various ceramic targets. The S contents in the quaternary alloy films were far beyond the reported solid solubility limits of S in single-phase ternary alloy ZnO1−ySy films. The bandgap of MgxZn1−xO1−ySy, inferred from optical transmission measurements, was narrower than the bandgap of MgxZn1−xO while broadened compared with that of ZnO1−ySy. The broadening effect was enhanced with the increase of Mg content. The simultaneous substitution of cation (Zn2+) and anion (O2−) by isoelectronic elements (Mg2+ and S2−) offers further flexibility for the band-gap engineering and potentially facilitates the p-type doping of ZnO.
Misalign-dependent double plasmon modes “switch” of gold triangular nanoplate dimers
Authors: Zhang Chun-hong , Zhu Jian , Li Jian-jun , Zhao Jun-wu
Published: February 2015

The optical properties of the edge-to-edge gold triangular nanoplate dimers have been studied in theory by discrete dipole approximation method. Two clearly separated plasmon modes (low-energy and high-energy modes) are observed. Each of the double plasmon modes could be selectively turned on or off by modulating the misalign value of the dimer. When the misalign is <60 nm, the low-energy mode plays the dominant role in the spectra. In this case, the electric field intensities at the tips along the polarization direction fade down, whereas the intense electric field in the gap gets more concentrative, as the misalign increases. However, as the misalign is increased to 100 nm, the high-energy mode dominates the spectrum. And the intense electric fields concentrated around the outer tips become stronger as the misalign increases. The “switch” process is also accompanied by the inversion of the field vectors in the gap. In addition, the wavelength separation and positions of the double plasmon modes could be tuned flexibly by adjusting the gap value and the thickness of the dimer, respectively. These findings are promising for the nanophotonic switch, nanomotor, molecular ruler, surface enhanced fluorescence, surface enhanced Raman scattering, dual channel biosensor, and molecular imaging applications.
Analysis of vegetation change associated with human disturbance using MODIS data on the rangelands of the Qinghai-Tibet Plateau
Authors: Zhao Haidi , Liu Shiliang , Dong Shikui , Su Xukun , Wang Xuexia , Wu Xiaoyu , Wu Lei , Zhang Xiang
Published: February 2015

This paper evaluated changes in vegetation from 2000 to 2012, based on 1-km resolution 16-day composite Moderate Resolution Imaging Spectroradiometer (MODIS) Normalised Difference Vegetation Index (NDVI), and related them to changes in estimates of human disturbance on the rangelands of the Qinghai-Tibet Plateau. The main rangeland types studied were desert, steppe and meadow with the latter mainly found in the southern and eastern parts of the study area. The results indicated that human disturbance was distributed mainly in the southern and eastern parts of the study area and corresponded with high NDVI values. The NDVI values showed an upward trend over the study period, with 28.5% of the study area exhibiting a significant increase. The proportion of rangelands that experienced a downward trend in NDVI increased as the level of human disturbance increased. Of the different rangeland types, meadow had the highest NDVI values, the greatest human disturbance, and the highest proportion of rangelands that exhibited a significant decrease in NDVI. Compared with areas with no human disturbance, meadow and steppe rangelands that experienced an increase in human disturbance had lower rates of increase in their NDVI values but, conversely, desert rangelands showed the opposite trend. In addition, it was found that precipitation had the dominant influence on NDVI values and that higher precipitation and slighter lower temperatures over the period of the study were related to an increase in NDVI values.
Local perceptions of rangeland degradation and climate change in the pastoral society of Qinghai-Tibetan Plateau
Authors: Wu Xiaoyu , Zhang Xiangfeng , Dong Shikui , Cai Hong , Zhao Tianren , Yang Wenjun , Jiang Rong , Shi Yandan , Shao Junlin
Published: February 2015

Rangelands provide several valuable ecological services and provide for the livelihoods of local herders on the Qinghai-Tibetan Plateau (QTP). However, rangelands are being degraded due to overgrazing, policy changes and climate change. In this context, a survey was conducted in Zhuaxixiulong township of Gansu Province, China to examine the rangeland management systems and identify problems herders are facing in terms of livestock production and livelihoods using a Participatory Rural Appraisal approach. The results indicated that local herders perceived recent trends in rangeland degradation, climatic change, and political changes, and had developed management practices to adapt to these changes, such as adjusting transhumance patterns, cooperating with local institutions and adopting more collective actions in production practices. This study suggests that, to promote a sustainable rangeland management system in the QTP, policy-makers should recognise indigenous knowledge systems of grazing practices and rangeland management, as well as the need for more advanced technical methods. More attention should be paid to recent changes in climate, social transformations and economic changes to enhance the viability of such a pastoral society. To ensure the sustainability of the social–ecological system, there is a need to strengthen public participation and cooperation with all types of institutions to formulate appropriate policies and improve public services.
Enhancing the resilience of coupled human and natural systems of alpine rangelands on the Qinghai-Tibetan Plateau
Authors: Dong Shikui , Sherman Ruth
Published: February 2015

This special issue covers a wide range of topics on the protection and sustainable management of alpine rangelands on the Qinghai-Tibetan Plateau (QTP), including Indigenous knowledge of sustainable rangeland management, science-policy interface for alpine rangeland biodiversity conservation, adaptations of local people to social and environmental changes and policy design for managing coupled human-natural systems of alpine rangelands.
Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae
Authors: Deng Junjing , Vine David J. , Chen Si , Nashed Youssef S. G. , Jin Qiaoling , Phillips Nicholas W. , Peterka Tom , Ross Rob , Vogt Stefan , Jacobsen Chris J.
Published: February 2015

Significance

X-ray fluorescence microscopy provides unparalleled sensitivity for measuring the distribution of trace elements in many-micrometer-thick specimens, whereas ptychography offers a path to the imaging of weakly fluorescing biological ultrastructure at beyond-focusing-optic resolution. We demonstrate here for the first time, to our knowledge, the combination of fluorescence and ptychography for imaging frozen-hydrated specimens at cryogenic temperatures, with excellent structural and chemical preservation. This combined approach will have significant impact on studies of the intracellular localization of nanocomposites with attached therapeutic or diagnostic agents, help elucidate the roles of trace metals in cell development, and further the study of diseases where trace metal misregulation is suspected (including neurodegenerative diseases).
Tetrahydrobiopterin and alkylglycerol monooxygenase substantially alter the murine macrophage lipidome
Authors: Watschinger Katrin , Keller Markus A. , McNeill Eileen , Alam Mohammad T. , Lai Steven , Sailer Sabrina , Rauch Veronika , Patel Jyoti , Hermetter Albin , Golderer Georg , Geley Stephan , Werner-Felmayer Gabriele , Plumb Robert S. , Astarita Giuseppe , Ralser Markus , Channon Keith M. , Werner Ernst R.
Published: February 2015

Significance

We have recently identified the sequence of the ether lipid-cleaving enzyme alkylglycerol monooxygenase. Like nitric oxide synthases and aromatic amino acid hydroxylases, alkylglycerol monooxygenase needs tetrahydrobiopterin as cofactor. Whereas the former enzymes have well-established roles in the cell, the physiology of alkylglycerol monooxygenase is still not clear. Here we show its regulation in murine macrophage differentiation and its dependence on the cofactor tetrahydrobiopterin in live murine macrophage-like RAW264.7 cells. Upon modulation of the activity of alkylglycerol monooxygenase and the key enzyme in tetrahydrobiopterin biosynthesis, we observe extensive changes in various lipid classes ranging from ether lipids to far more complex lipids. These findings point to an important role of tetrahydrobiopterin in cellular lipid homeostasis.
Contribution of reactive oxygen species to cerebral amyloid angiopathy, vasomotor dysfunction, and microhemorrhage in aged Tg2576 mice
Authors: Han Byung Hee , Zhou Meng-liang , Johnson Andrew W. , Singh Itender , Liao Fan , Vellimana Ananth K. , Nelson James W. , Milner Eric , Cirrito John R. , Basak Jacob , Yoo Min , Dietrich Hans H. , Holtzman David M. , Zipfel Gregory Joseph
Published: February 2015

Significance

One of the hallmarks of Alzheimer’s disease (AD) is cerebral amyloid angiopathy (CAA), which is a strong and independent risk factor for cerebral hemorrhage, ischemic stroke, and dementia. However, the mechanisms by which CAA contributes to these conditions are poorly understood. Results from the present study provide strong evidence that vascular oxidative stress plays a causal role in CAA-induced cerebrovascular dysfunction, CAA-induced cerebral hemorrhage, and CAA formation, itself. They also suggest that NADPH oxidase is the source of this oxidative stress and that strategies to inhibit NADPH oxidase may have therapeutic potential in patients with AD and CAA.
Correlation between ground state and orbital anisotropy in heavy fermion materials
Authors: Willers Thomas , Strigari Fabio , Hu Zhiwei , Sessi Violetta , Brookes Nicholas B. , Bauer Eric D. , Sarrao John L. , Thompson J. D. , Tanaka Arata , Wirth Steffen , Tjeng Liu Hao , Severing Andrea
Published: February 2015

Significance

The ground state of materials with strong electronic correlations depends on a delicate balance among competing interactions. The strongly correlated compounds Ce
M
In
5
, with
M
= Co, Rh, and Ir, exhibit superconducting and magnetic ground states as well as Fermi surface changes upon substituting one
M
element for another and become even higher temperature superconductors when Ce is substituted by Pu. They are therefore recognized as important model systems in which a search for parameters correlating with the occurrence of these ground states could be successful. The present X-ray absorption study of CeRh

1−
x

Ir

x

In
5
reveals that anisotropy of the Ce 4
f
-wave function is a significant parameter that is highly sensitive to the ground-state formation and should be taken into account when modeling these systems.
Brain 5-HT deficiency increases stress vulnerability and impairs antidepressant responses following psychosocial stress
Authors: Sachs Benjamin D. , Ni Jason R. , Caron Marc G.
Published: February 2015

Significance

The biological factors that determine whether an individual develops mental illness, such as depression or posttraumatic stress disorder, or responds adequately to pharmacotherapy remain almost completely unknown. Using genetically modified mice, we demonstrate that low levels of brain serotonin lead to increased vulnerability to psychosocial stress and prevent the antidepressant-like effects of fluoxetine following stress exposure. Our data also show that inhibiting the lateral habenula can reverse stress-induced behavioral avoidance in serotonin-deficient animals, which fail to respond to fluoxetine. Our results provide additional insight into the serotonin deficiency hypothesis of depression and highlight the potential of targeting the lateral habenula to treat depression and anxiety disorders in patients who fail to respond to selective serotonin reuptake inhibitors.
Highly efficient conversion of superoxide to oxygen using hydrophilic carbon clusters
Authors: Samuel Errol L. G. , Marcano Daniela C. , Berka Vladimir , Bitner Brittany R. , Wu Gang , Potter Austin , Fabian Roderic H. , Pautler Robia G. , Kent Thomas A. , Tsai Ah-Lim , Tour James M.
Published: February 2015

Significance

Mechanistic studies of nontoxic hydrophilic carbon cluster nanoparticles show that they are able to accomplish the direct conversion of superoxide to dioxygen and hydrogen peroxide. This is accomplished faster than in most single-active-site enzymes, and it is precisely what dioxygen-deficient tissue needs in the face of injury where reactive oxygen species, particularly superoxide, overwhelm the natural enzymes required to remove superoxide. We confirm here that the hydrophilic carbon clusters are unreactive toward nitric oxide radical, which is a potent vasodilator that also has an important role in neurotransmission and cytoprotection. The mechanistic results help to explain the preclinical efficacy of these carbon nanoparticles in mitigating the deleterious effects of superoxide on traumatized tissue.
Automated analysis of high-throughput B-cell sequencing data reveals a high frequency of novel immunoglobulin V gene segment alleles
Authors: Gadala-Maria Daniel , Yaari Gur , Uduman Mohamed , Kleinstein Steven H.
Published: February 2015

Significance

High-throughput sequencing of B-cell immunoglobulin receptors is providing unprecedented insight into adaptive immunity. A key step in analyzing these data involves assignment of the germline variable (V), diversity (D), and joining (J) gene-segment alleles that comprise each immunoglobulin sequence by matching them against a database of known V(D)J alleles. However, this process will fail for sequences that use previously undetected alleles, whose frequency in the population is unclear. Here we describe TIgGER, a computational method that significantly improves V(D)J allele assignments by first determining the complete set of gene segments carried by a subject, including novel alleles. The application of TIgGER identifies a surprisingly high frequency of novel alleles, highlighting the critical need for this approach.
Critical and maximally informative encoding between neural populations in the retina
Authors: Kastner David B. , Baccus Stephen A. , Sharpee Tatyana O.
Published: February 2015

Significance

It is unknown what functional properties influence the number of cell types in the brain. Here we show how one can use a powerful framework from physics that describes the transitions between different phases of matter, such as between liquid and gas, to specify under what conditions it becomes optimal to split neural populations into new subtypes to maximize information transmission. These results outline a conceptual framework that spans both physical and biological systems and can be used to explain the emergence of different functional classes of neuronal types.
Greedy scheduling of cellular self-replication leads to optimal doubling times with a log-Frechet distribution
Authors: Pugatch Rami
Published: February 2015

Significance

In production scheduling, a temporal assignment of tasks to their respective processing units is sought, such that precedence and resource constraint are satisfied and an optimization goal is minimized. So how is bacterial self-replication scheduled? Scarcity of resources creates a hard-to-solve scheduling problem in the worst case. Here, we show that proper loading of metabolic and catalytic reservoirs results in optimal scheduling, provided that the catalytic processing units are “greedy,” i.e., do not idle if they can perform a task. The distribution of doubling times of optimally scheduled self-replication has a universal form—the log-Frechet distribution. Recent measurements of doubling times of
Escherichia coli
in different media well fit this distribution, suggesting that
E. coli
optimally scheduled its replication in these experiments.
Visualization of a radical B
12
enzyme with its G-protein chaperone
Authors: Jost Marco , Cracan Valentin , Hubbard Paul A. , Banerjee Ruma , Drennan Catherine L.
Published: February 2015

Significance

Metalloproteins are ubiquitous, accounting for about 30–50% of all proteins. Their functions are wide-ranging, but metalloproteins are frequently used to carry out challenging molecular transformations. Metalloprotein reactivity comes at a price, however, often requiring specialized molecular machinery for holoenzyme assembly. G-protein metallochaperones are an important part of this assembly apparatus, but an understanding of their molecular mechanisms has been hindered by a lack of structural data. Here, we describe crystal structures of a G-protein metallochaperone together with a target enzyme, in this case an adenosylcobalamin-dependent radical enzyme, thereby providing a visualization of the molecular architecture of the G-protein:target enzyme complex.
Extensive tissue-related and allele-related mtDNA heteroplasmy suggests positive selection for somatic mutations
Authors: Li Mingkun , Schröder Roland , Ni Shengyu , Madea Burkhard , Stoneking Mark
Published: February 2015

Significance

Heteroplasmy is the existence of different mtDNA sequences within an individual due to somatic or inherited mutations, and it has been implicated in many mtDNA-related diseases, other diseases, cancer, and aging. However, little is known about how heteroplasmy varies across different tissues from the same individual; here, we analyzed heteroplasmy variation across the entire mtDNA genome in 12 tissues obtained at autopsy from each of 152 individuals. Our results suggest that in addition to neutral processes and negative selection, positive selection has an important influence on heteroplasmy: As individuals get older, specific alleles are selected for at specific nucleotide positions in specific tissues. The functional consequences of these positively selected somatic mutations may play a role in human health and disease.
Localizing a gate in CFTR
Authors: Gao Xiaolong , Hwang Tzyh-Chang
Published: February 2015

Significance

Cystic fibrosis transmembrane conductance regulator (CFTR), albeit a bona fide member of the ATP-binding cassette (ABC) transporter superfamily, is an ATP-gated chloride channel. However, phylogenetic analysis has led to a popular conjecture that CFTR evolves from a primordial ABC exporter by simply degenerating the cytoplasmic gate. This degraded transporter hypothesis predicts that CFTR’s gate is located at the external end of the substrate translocation pathway as the one documented in the crystal structures of ABC exporters. Here we provide experimental data supporting the presence of a gate in CFTR at a segment that may also serve as the selectivity filter. This functional duality of a restrictive segment close to the middle of the pore axis distinguishes CFTR from its myriad brethren in the ABC protein family.
Arabidopsis
OR proteins are the major posttranscriptional regulators of phytoene synthase in controlling carotenoid biosynthesis
Authors: Zhou Xiangjun , Welsch Ralf , Yang Yong , Álvarez Daniel , Riediger Matthias , Yuan Hui , Fish Tara , Liu Jiping , Thannhauser Theodore W. , Li Li
Published: February 2015

Significance

Carotenoids are indispensable to plants and humans. Despite significant achievements in carotenoid research, we still lack the fundamental knowledge of the regulatory mechanisms underlying carotenogenesis in plants. Phytoene synthase (PSY) and ORANGE (OR) are the two key proteins for carotenoid biosynthesis and accumulation in plastids. This study shows that OR family proteins interact directly with PSY and function as the major regulators of active PSY protein abundance in mediating carotenoid biosynthesis. The findings establish posttranscriptional regulation of PSY as a novel way to control carotenoid biosynthesis in plants and provide strategies for crop nutritional quality improvement.
Toward link predictability of complex networks
Authors: Lü Linyuan , Pan Liming , Zhou Tao , Zhang Yi-Cheng , Stanley H. Eugene
Published: February 2015

Significance

Quantifying a network's link predictability allows us to (i) evaluate predictive algorithms associated with the network, (ii) estimate the extent to which the organization of the network is explicable, and (iii) monitor sudden mechanistic changes during the network's evolution. The hypothesis of this paper is that a group of links is predictable if removing them has only a small effect on the network's structural features. We introduce a quantitative index for measuring link predictability and an algorithm that outperforms state-of-the-art link prediction methods in both accuracy and universality. This study provides fundamental insights into important scientific problems and will aid in the development of information filtering technologies.
Lack of exercise leads to significant and reversible loss of scale invariance in both aged and young mice
Authors: Gu Changgui , Coomans Claudia P. , Hu Kun , Scheer Frank A. J. L. , Stanley H. Eugene , Meijer Johanna H.
Published: February 2015

Significance

Healthy systems are characterized by scale invariance across multiple timescales. We investigated whether loss of scale invariance that occurs with aging and disease can be counteracted by exercise, in four age groups of mice. Surprisingly, we observed that lack of exercise was detrimental not only in old but also in young mice, raising the possibility of an unforeseen role of behavioral activity for health in aged and young subjects alike. Moreover, we show that scale invariance could be restored by high levels of exercise, even in old animals. The World Health Organization has pinpointed lack of exercise and a sedentary lifestyle as a major risk factor for various diseases. Our measures may guide health programs.
Glucagon receptor antibody completely suppresses type 1 diabetes phenotype without insulin by disrupting a novel diabetogenic pathway
Authors: Wang May-Yun , Yan Hai , Shi Zhiqing , Evans Matthew R. , Yu Xinxin , Lee Young , Chen Shiuhwei , Williams Annie , Philippe Jacques , Roth Michael G. , Unger Roger H.
Published: February 2015

Significance

Subcutaneous injections of insulin sustain life in mammals unable to produce insulin (type 1 diabetes) but do not prevent hyperglycemic and hypoglycemic swings or decrease hemoglobin A1c levels to normal amounts. In mice treated with insulin alone, repeated episodes of transient elevated blood glucose cause long-term damage. We show that in mice with type 1 diabetes treated with insulin, the transient high blood glucose levels require production of glucagon, a hormone that will cause the liver to produce more glucose. Blocking the action of glucagon with an antibody to the glucagon receptor completely normalizes blood glucose and hemoglobin A1c in the complete absence of insulin therapy. Suppressing glucagon action in combination with low-dose insulin would be a superior treatment for type 1 diabetes.
Calorimetric glass transition in a mean-field theory approach
Authors: Mariani Manuel Sebastian , Parisi Giorgio , Rainone Corrado
Published: February 2015

Significance

Understanding the properties of glasses is one of the major open challenges of theoretical physics. Making analytical predictions is usually very difficult for the known glassy models. Moreover, in experiments and numerical simulations thermalization of glasses cannot be achieved without sophisticated procedures, such as the vapor deposition technique. In this work we study a glassy model that is simple enough to be analytically solved and that can be thermalized in the glassy phase with a simple numerical method, opening the door to an intensive comparison between replica theory predictions and numerical outcomes.
Transplantation of bovine adrenocortical cells encapsulated in alginate
Authors: Balyura Mariya , Gelfgat Evgeny , Ehrhart-Bornstein Monika , Ludwig Barbara , Gendler Zohar , Barkai Uriel , Zimerman Baruch , Rotem Avi , Block Norman L. , Schally Andrew V. , Bornstein Stefan R.
Published: February 2015

Significance

Adrenal insufficiency is a life-threatening disorder that requires a complex and permanent hormone replacement strategy. All current replacement schemes suffer from numerous problems, as they fail to restore circadian variations in hormone secretion. Therefore, adrenal cell transplantation could be a preferable therapeutic alternative for patients suffering from primary adrenal dysfunction. This strategy is critically limited, however, by the lack of suitable donors of human organs and the requirement of chronic immunosuppression. Transplantation of immunoisolated xenogeneic adrenal cells could and would be a promising alternative for these patients. The most significant accomplishment of this study is the creation of long-term functional and immunoisolated artificial adrenals and their transplantation into animal models of adrenal insufficiency.
Mechanism of initiation of aggregation of p53 revealed by Φ-value analysis
Authors: Wang GuoZhen , Fersht Alan R.
Published: February 2015

Significance

The tumor suppressor p53 is inactivated by aggregation in a substantial number of tumors, and those oncogenic mutants coaggregate with WT protein and other tumor suppressors. Inhibition of aggregation by small molecules is a possible drug therapy. p53 aggregation appears to have much simpler kinetics than commonly encountered in fibrillation, with two rate-determining sequential, apparently first-order, steps. We showed by combining mutagenesis and kinetics that the rate determining steps involve two molecules of p53 extensively unfolding and reacting in a bimolecular process that can appear first order. The mechanism provides a basis for understanding the progress of aggregation and coaggregation and points to the most effective drug targeting sites.
Propagation of aggregated p53: Cross-reaction and coaggregation vs. seeding
Authors: Wang GuoZhen , Fersht Alan R.
Published: February 2015

Significance

Aggregation of tumor suppressor p53 oncogenic mutants not only loses their activity but may also lead to gain of oncogenic function, possibly by coaggregation with other proteins. We explored how a destabilized p53 mutant may coaggregate with WT p53 and its homologs p63 and p73. The results are explained by the simple two-step initiation mechanism we proposed. Rather than the oncogenic mutant seeding coaggregation by a prion-like process, coaggregation results from the simultaneous unfolding and cross-reaction of WT and mutant molecules. Consequently, preformed p53 aggregate displays little seeding of aggregation of p53, and high concentrations of p53 mutants are required to trap WT p53 into aggregate. Coaggregation is predominantly by trapping rather than seeding and induced propagation.
Dysregulation ofEscherichia coliα-hemolysin expression alters the course of acute and persistent urinary tract infection
Authors: Nagamatsu Kanna , Hannan Thomas J. , Guest Randi L. , Kostakioti Maria , Hadjifrangiskou Maria , Binkley Jana , Dodson Karen , Raivio Tracy L. , Hultgren Scott J.
Published: February 2015

Significance

The majority of urinary tract infections (UTIs) are caused by uropathogenicEscherichia coli(UPEC). Upon UPEC infection, exfoliation of host bladder epithelial (urothelial) cells leads to sloughing of bacteria-laden cells into the urine for expulsion. However, it can also facilitate bacterial dissemination into deeper tissues. Thus, the balance and timing of exfoliation are important in determining disease outcomes. Here, we investigate host–pathogen dynamics in human urothelial cells in vitro and in murine model of acute cystitis. We discovered that the CpxR response regulator-CpxA sensor kinase two-component system regulates the expression of the pore-forming toxin α-hemolysin (HlyA) in response to environmental conditions. HlyA, in turn, is critical for fine-tuning the dynamics of host cell exfoliation and enhancing UPEC fitness during acute UTI.
Silencing LRH-1 in colon cancer cell lines impairs proliferation and alters gene expression programs
Authors: Bayrer James R. , Mukkamala Sridevi , Sablin Elena P. , Webb Paul , Fletterick Robert J.
Published: February 2015

Significance

This work addresses a key question in the field of liver receptor homolog-1 (LRH-1) pathophysiology in colorectal cancer (CRC)—namely, does LRH-1 contribute exclusively to tumorigenesis, or does LRH-1 also drive established CRC tumor growth? These two models have widely different implications for pharmaceutical targeting in CRC. To our knowledge, our work is the first to demonstrate that silencing of LRH-1 in established human CRC cell lines impairs proliferation though G0/G1 phase prolongation. Our microarray gene expression analysis shows that loss of LRH-1 expression yields alterations in diverse cellular pathways consistent with the critical role of LRH-1 in CRC. Taken together, our study suggests that a subset of CRC patients could benefit from selective antagonism of LRH-1.
Convergence of ion channel genome content in early animal evolution
Authors: Liebeskind Benjamin J. , Hillis David M. , Zakon Harold H.
Published: February 2015

Significance

The early evolution of animal nervous systems is poorly understood, but comparative genomics provides a new window into the past. One important controversy is about whether nervous systems evolved just once or independently in different animal lineages. In this work, we explore the history of the gene families most central to nervous system function: ion channels. We track when these gene families expanded in animal evolution and find that these gene families radiated on several occasions and, in some cases, underwent periods of contraction. The multiple origins of these gene families may signify large-scale convergent evolution of nervous system complexity.
Expanding horizons in the study of World Englishes with the 1.9 billion word Global Web-based English Corpus (GloWbE)
Authors: Davies Mark , Fuchs Robert
Published: February 2015

In this paper, we provide an overview of the new GloWbE Corpus — the Corpus of Global Web-based English. GloWbE is based on 1.9 billion words in 1.8 million web pages from 20 different English-speaking countries. Approximately 60 percent of the corpus comes from informal blogs, and the rest from a wide range of other genres and text types. Because of its large size, its architecture and interface, the corpus can be used to examine many types of variation among dialects, which might not be possible with other corpora — including variation in lexis, morphology, (medium- and low-frequency) syntactic constructions, variation in meaning, as well as discourse and its relationship to culture.
Response to Davies and Fuchs
Authors: Mair Christian
Published: February 2015

Commentary to: Davies, Mark, and Robert Fuchs. 2015. "Expanding horizons in the study of World Englishes with the 1.9 billion word Global Web-based English Corpus (GloWbE)". English World-Wide 36:1–28 (This issue). DOI:10.1075/eww.36.1.01dav
Response to Davies and Fuchs
Authors: Peters Pam
Published: February 2015

Commentary to: Davies, Mark, and Robert Fuchs. 2015. "Expanding horizons in the study of World Englishes with the 1.9 billion word Global Web-based English Corpus (GloWbE)". English World-Wide 36:1–28 (This issue). DOI:10.1075/eww.36.1.01dav
A reply
Authors: Davies Mark , Fuchs Robert
Published: February 2015

A reply to the commentaries by Christian Mair (DOI:10.1075/eww.36.1.02mai), Joybrato Mukherjee (DOI:10.1075/eww.36.1.02muk), Gerald Nelson (DOI:10.1075/eww.36.1.02nel), and Pam Peters (DOI:10.1075/eww.36.1.02pet).
β-Thujaplicin modulates estrogen receptor signaling and inhibits proliferation of human breast cancer cells
Authors: Ko Jiwon , Bao Cheng , Park Hyun-Chang , Kim Minchae , Choi Hyung-Kyoon , Kim Young-Suk , Lee Hong Jin
Published: February 2015

β-Thujaplicin, one of the major constituents in Chamaecyparis obtusa, has been demonstrated to exert different health beneficial efficacy, but the role of β-thujaplicin in regulating mammary tumorigenesis has not been investigated. In this study, we found that β-thujaplicin significantly suppressed the proliferation through arresting the cell cycle transition from G1 to S phase as well as inhibited the expression of cell cycle-related proteins, cyclin D1, and cyclin-dependent kinase 4 (CDK4) in MCF-7 and T47D luminal subtype breast cancer cells. In addition, estrogen receptor α (ER-α) was down-regulated by β-thujaplicin via enhanced proteolysis by ubiquitination, which led to cell growth inhibition. These results suggest that β-thujaplicin may be considered as a potent agent regulating the hormone sensitive mammary tumorigenesis.
Rapid Communication: Response cost to repeated displays—When previous distractors become targets
Authors: Yang Yingying , Merrill Edward C.
Published: February 2015

A varied-target search task was used to evaluate the response cost of previous distractors becoming current targets in repeated visual search. We compared the relative contributions of distractor identity and location to producing response cost. During an exposure phase, half of the items were possible targets in each repeated display, and the other half were always distractors. Participants searched for a different target from the set of potential targets when the search displays were repeated. In the test phase of Experiments 1a and 1b, the roles of targets and distractors were reversed while the overall configuration was unchanged. Results indicated significant contextual costs after the switch of identities/locations between distractors and targets. In the test phase of Experiments 2a and 2b, target identities were changed again but the target locations remained the same. Less response cost was observed in this condition relative to when both identities and locations were changed. Proximity between target and distractors in the repeated displays also influenced response cost. The mechanisms responsible for the various response cost effects and the interplay between identity, location, and proximity in the production of response cost were discussed.