bluuebunny/crossref_metadata_2025 huggingface dataset:
Graphical and numerical diagnostic tools to assess suitability of multiple imputations and imputation models
Authors: Bondarenko Irina , Raghunathan Trivellore
Published: March 2016

Multiple imputation has become a popular approach for analyzing incomplete data. Many software packages are available to multiply impute the missing values and to analyze the resulting completed data sets. However, diagnostic tools to check the validity of the imputations are limited, and the majority of the currently available methods need considerable knowledge of the imputation model. In many practical settings, however, the imputer and the analyst may be different individuals or from different organizations, and the analyst model may or may not be congenial to the model used by the imputer. This article develops and evaluates a set of graphical and numerical diagnostic tools for two practical purposes: (i) for an analyst to determine whether the imputations are reasonable under his/her model assumptions without actually knowing the imputation model assumptions; and (ii) for an imputer to fine tune the imputation model by checking the key characteristics of the observed and imputed values. The tools are based on the numerical and graphical comparisons of the distributions of the observed and imputed values conditional on the propensity of response. The methodology is illustrated using simulated data sets created under a variety of scenarios. The examples focus on continuous and binary variables, but the principles can be used to extend methods for other types of variables. Copyright © 2016 John Wiley & Sons, Ltd.
Anodic Oxidation of Caffeine and Theophylline in Glacial Acetic Acid
Authors: Quintanilla Gloria , Usarralde Ángela , Pérez Iván , Gargiulo Maria L. , Yakupoglu Gökce , Martín Avelino , Barba Fructuoso
Published: March 2016

The anodic oxidation of caffeine and theophylline has been carried out at a controlled potential in a one compartment cell using glassy‐carbon as the anode, platinum as the cathode and glacial acetic acid/sodium acetate as solvent‐supporting‐electrolyte (SSE). The oxidation of caffeine yields 1,3,8‐trimethyl‐1,3,6,8‐tetrazaspiro[4.4]nonane‐2,4,7,9‐tetrone and (4‐acetoxy‐1,3,7‐trimethyl‐2,6,8‐trioxo‐9H‐purin‐5‐yl) acetate. Despite of the different structure, the oxidation of theophylline leads only to the same spiro compound 1,3,8‐trimethyl‐1,3,6,8‐tetrazaspiro[4.4]nonane‐2,4,7,9‐tetrone as in the case of caffeine. The structure of both compounds is described and the reaction mechanism is discussed.
Creating Pores on Graphene Platelets by Low‐Temperature KOH Activation for Enhanced Electrochemical Performance
Authors: Wu Shuilin , Chen Guanxiong , Kim Na Yeon , Ni Kun , Zeng Wencong , Zhao Yuan , Tao Zhuchen , Ji Hengxing , Lee Zonghoon , Zhu Yanwu
Published: March 2016

KOH activation of microwave exfoliated graphite oxide (MEGO) is investigated in detail at temperatures of 450–550 °C. Out of the activation temperature range conventionally used for the preparation of activated carbons (>600 °C), the reaction between KOH and MEGO platelets at relatively low temperatures allows one to trace the structural transition from quasi‐two‐dimensional graphene platelets to three‐dimensional porous carbon. In addition, it is found that nanometer‐sized pores are created in the graphene platelets at the activation temperature of around 450 °C, leading to a carbon that maintains the platelet‐like morphology, yet with a specific surface area much higher than MEGO (e.g., increased from 156 to 937 m2 g–1). Such a porous yet highly conducting carbon shows a largely enhanced electrochemical activity and thus improved electrochemical performance when being used as electrodes in supercapacitors. A specific capacitance of 265 F g–1 (185 F cm–3) is obtained at a current density of 1 A g–1 in 6 m KOH electrolyte, which remains 223 F g–1 (156 F cm–3) at the current density of 10 A g–1.
Ultrasound in the assessment of hepatomegaly: A simple technique to determine an enlarged liver using reliable and valid measurements
Authors: Childs Jessie T , Esterman Adrian J , Thoirs Kerry A , Turner Richard C
Published: March 2016

Introduction

Knowledge of the size of the liver is an important factor in diagnosing liver disease. Hepatomegaly is a term used to describe a liver that is enlarged beyond its normal dimensions, and ultrasound is often a front line investigation in the suspicion of hepatomegaly. This study sought to develop a reference range for the size of the normal liver using a simple, reliable and valid measurement technique.

Methods

Two ultrasound images of the liver and a blood test were taken from 126 participants. Three simple linear measurements were taken from these two images and converted to a liver volume using a published equation.

Results

The reference range for liver volume in adults without liver pathology was found to be 1060–2223 cm3.

Conclusion

This new measurement technique and reference range is simple and easy to perform in the clinical environment. It has the potential to discriminate a liver normal in size to one with hepatomegaly.
The molecular basis of craniofacial placode development
Authors: Singh Sunita , Groves Andrew K.
Published: March 2016

The sensory organs of the vertebrate head originate from simple ectodermal structures known as cranial placodes. All cranial placodes derive from a common domain adjacent to the neural plate, the preplacodal region, which is induced at the border of neural and non‐neural ectoderm during gastrulation. Induction and specification of the preplacodal region is regulated by the fibroblast growth factor, bone morphogenetic protein,WNT, and retinoic acid signaling pathways, and characterized by expression of theEYAandSIXfamily of transcriptional regulators. Once the preplacodal region is specified, different combinations of local signaling molecules and placode‐specific transcription factors, including competence factors, promote the induction of individual cranial placodes along the neural axis of the head region. In this review, we summarize the steps of cranial placode development and discuss the roles of the main signaling molecules and transcription factors that regulate these steps during placode induction, specification, and development.WIREs Dev Biol2016, 5:363–376. doi: 10.1002/wdev.226

This article is categorized under:

Gene Expression and Transcriptional Hierarchies > Cellular Differentiation

Early Embryonic Development > Gastrulation and Neurulation

Early Embryonic Development > Development to the Basic Body Plan
Mixed Alkali Neodymium Orthoborates: K9Li3Nd3(BO3)7 and A2LiNd(BO3)2 (A = Rb, Cs)
Authors: Chen Pengyun , Xia Mingjun , Li Rukang
Published: March 2016

Crystals of mixed alkali neodymium orthoborates, K9Li3Nd3(BO3)7 and A2LiNd(BO3)2 (A = Rb, Cs) were obtained by spontaneous crystallization. K9Li3Nd3(BO3)7 crystallizes in space group P2/c with cell parameters of a = 11.4524(7) Å, b = 10.1266(6) Å, c = 12.3116 (10) Å, β = 122.0090(10)°. In the structure, NdO8 polyhedra share corners and connect with planer BO3 groups to form infinite [Nd3B3O21]n chains. These chains are linked by additional BO3 groups to produce a double layer of [Nd6B6O38]n blocks in the ac plane with K and Li ions filled into the cavities. A2LiNd(BO3)2 (A = Rb, Cs) crystallizes in space group Pbcm, with cell parameters of a = 7.113(2) Å, b = 9.691(3) Å and c = 10.135(3) Å for Rb2LiNd(BO3)2, and a = 7.2113(3) Å, b = 9.9621(4) Å, and c = 10.3347(4) Å for Cs2LiNd(BO3)2. In the structure, NdO8 polyhedra are corner‐sharing with each other and further interlinked by BO3 groups to comprise the infinite [Nd4B4O24] sheets in the bc plane, with Rb/Cs and Li ions occupying the interlayered space. The compounds show effective near‐IR emission and their associated lifetimes are obtained by fluorescence spectra.
An analytical assessment of finite element and isogeometric analyses of the whole spectrum of Timoshenko beams
Authors: Cazzani Antonio , Stochino Flavio , Turco Emilio
Published: March 2016

The theoretical results relevant to the vibration modes of Timoshenko beams are here used as benchmarks for assessing the correctness of the numerical values provided by several finite element models, based on either the traditional Lagrangian interpolation or on the recently developed isogeometric approach. Comparison of results is performed on both spectrum error (in terms of the detected natural frequencies) and on the l2 relative error (in terms of the computed eigenmodes): this double check allows detecting for each finite element model, and for a discretization based on the same number of degrees‐of‐freedom, N, the frequency threshold above which some prescribed accuracy level is lost, and results become more and more unreliable. Hence a quantitative way of measuring the finite element performance in modeling a Timoshenko beam is proposed. The use of Fast Fourier Transform is finally employed, for a selected set of vibration modes, to explain the reasons of the accuracy decay, mostly linked to a poor separation of the natural frequencies in the spectrum, which is responsible of some aliasing of modes.
Predicting progression from mild cognitive impairment to Alzheimer's disease using longitudinal callosal atrophy
Authors: Lee Sang Han , Bachman Alvin H. , Yu Donghyeon , Lim Johan , Ardekani Babak A. ,   Alzheimer's Disease Neuroimaging Initiative
Published: March 2016

Introduction

We investigate whether longitudinal callosal atrophy could predict conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD).

Methods

Longitudinal (baseline + 1‐year follow‐up) MRI scans of 132 MCI subjects from the Alzheimer's Disease Neuroimaging Initiative were used. A total of 54 subjects did not convert to AD over an average (±SD) follow‐up of 5.46 (±1.63) years, whereas 78 converted to AD with an average conversion time of 2.56 (±1.65) years. Annual change in the corpus callosum thickness profile was calculated from the baseline and 1‐year follow‐up MRI. A logistic regression model with fused lasso regularization for prediction was applied to the annual changes.

Results

We found a sex difference. The accuracy of prediction was 84% in females and 61% in males. The discriminating regions of corpus callosum differed between sexes. In females, the genu, rostrum, and posterior body had predictive power, whereas the genu and splenium were relevant in males.

Discussion

Annual callosal atrophy predicts MCI‐to‐AD conversion in females more accurately than in males.
A symbolic characterization of the horseshoe locus in the Hénon family
Authors: BEDFORD ERIC , SMILLIE JOHN
Published: March 2016

We consider the family of quadratic Hénon diffeomorphisms of the plane $\mathbb{R}^{2}$. A map will be said to be a ‘horseshoe’ if its restriction to the non-wandering set is hyperbolic and conjugate to the full 2-shift. We give a criterion for being a horseshoe based on an auxiliary coding which describes positions of points relative to the stable manifold of one of the fixed points. In addition we describe the topological conjugacy type of maps on the boundary of the horseshoe locus. We use complex techniques and we work with maps in a parameter region which is a two-dimensional analog of the familiar ‘$1/2$-wake’ for the quadratic family $p_{c}(z)=z^{2}$.
Lebesgue orbit equivalence of multidimensional Borel flows: A picturebook of tilings
Authors: SLUTSKY KONSTANTIN
Published: March 2016

The main result of the paper is classification of free multidimensional Borel flows up to Lebesgue orbit equivalence, by which we mean an orbit equivalence that preserves the Lebesgue measure on each orbit. Two non-smooth $\mathbb{R}^{d}$-flows are shown to be Lebesgue orbit equivalent if and only if they admit the same number of invariant ergodic probability measures.
Four-cycle free graphs, height functions, the pivot property and entropy minimality
Authors: CHANDGOTIA NISHANT
Published: March 2016

Fix $d\geq 2$. Given a finite undirected graph ${\mathcal{H}}$ without self-loops and multiple edges, consider the corresponding ‘vertex’ shift, $\text{Hom}(\mathbb{Z}^{d},{\mathcal{H}})$, denoted by $X_{{\mathcal{H}}}$. In this paper, we focus on ${\mathcal{H}}$ which is ‘four-cycle free’. There are two main results of this paper. Firstly, that $X_{{\mathcal{H}}}$ has the pivot property, meaning that, for all distinct configurations $x,y\in X_{{\mathcal{H}}}$, which differ only at a finite number of sites, there is a sequence of configurations $x=x^{1},x^{2},\ldots ,x^{n}=y\in X_{{\mathcal{H}}}$ for which the successive configurations $x^{i},x^{i+1}$ differ exactly at a single site. Secondly, if ${\mathcal{H}}$ is connected ,then $X_{{\mathcal{H}}}$ is entropy minimal, meaning that every shift space strictly contained in $X_{{\mathcal{H}}}$ has strictly smaller entropy. The proofs of these seemingly disparate statements are related by the use of the ‘lifts’ of the configurations in $X_{{\mathcal{H}}}$ to the universal cover of ${\mathcal{H}}$ and the introduction of ‘height functions’ in this context.
Impact of a high-speed train of microdrops on a liquid pool
Authors: Bouwhuis Wilco , Huang Xin , Chan Chon U , Frommhold Philipp E. , Ohl Claus-Dieter , Lohse Detlef , Snoeijer Jacco H. , van der Meer Devaraj
Published: March 2016

A train of high-speed microdrops impacting on a liquid pool can create a very deep and narrow cavity, reaching depths more than 1000 times the size of the individual drops. The impact of such a droplet train is studied numerically using boundary integral simulations. In these simulations, we solve the potential flow in the pool and in the impacting drops, taking into account the influence of liquid inertia, gravity and surface tension. We show that for microdrops the cavity shape and maximum depth primarily depend on the balance of inertia and surface tension and discuss how these are influenced by the spacing between the drops in the train. Finally, we derive simple scaling laws for the cavity depth and width.
Heat flux correlation for high-speed flow in the transitional regime
Authors: Singh Narendra , Schwartzentruber Thomas E.
Published: March 2016

An analytical correlation is developed for stagnation-point heat flux on spherical objects travelling at high velocity which is accurate for conditions ranging from the continuum to the free-molecular flow regime. Theoretical analysis of the Burnett and super-Burnett equations is performed using simplifications from shock-wave and boundary-layer theory to determine the relative contribution of higher-order heat flux terms compared with the Fourier heat flux (assumed in the Navier–Stokes equations). A rarefaction parameter ($W_{r}\equiv M_{\infty }^{2{\it\omega}}/Re_{\infty }$), based on the free-stream Mach number ($M_{\infty }$), the Reynolds number ($Re_{\infty }$) and the viscosity–temperature index (${\it\omega}$), is identified as a better correlating parameter than the Knudsen number in the transition regime. By studying both the Burnett and super-Burnett equations, a general form for the entire series of higher-order heat flux contributions is obtained. The resulting heat flux expression includes terms with dependence on gas properties, stagnation to wall-temperature ratio and a main dependence on powers of the rarefaction parameter$W_{r}$. The expression is applied as a correction to the Fourier heat flux and therefore can be combined with any continuum-based correlation of choice. In the free-molecular limit, a bridging function is used to ensure consistency with well-established free-molecular flow theory. The correlation is then fitted to direct simulation Monte Carlo (DSMC) solutions for stagnation-point heat flux in high-speed nitrogen flows. The correlation is shown to accurately capture the variation in heat flux predicted by the DSMC method in the transition flow regime, while limiting to both continuum and free-molecular values.
Numerical investigation of a honeycomb liner grazed by laminar and turbulent boundary layers
Authors: Zhang Qi , Bodony Daniel J.
Published: March 2016

Direct numerical simulations are used to study the interaction of a cavity-backed circular orifice with grazing laminar and turbulent boundary layers and incident sound waves. The flow conditions and geometry are representative of single degree-of-freedom acoustic liners applied in the inlet and exhaust ducts of aircraft engines and are the same as those from experiments conducted at NASA Langley. The simulations identify the fluid mechanics of how the sound field and state of the grazing boundary layer impact the in-orifice flow and suggest a simple flow analogy that enables scaling estimates. From the scaling estimates the simulations are then used to develop reduced-order models for the in-orifice flow and a time-domain impedance model is constructed. The liner is found to increase drag at all conditions studied by an amount that increases with the incident sound pressure amplitude.
A nonlinear and semi-analytical actuator disk method accounting for general hub shapes. Part 1. Open rotor
Authors: Bontempo R. , Manna M.
Published: March 2016

The paper presents a newly developed method for the analysis of the flow around open rotors characterised by hubs of general shape. The exact and implicit solution of the axysimmetric, inviscid and incompressible flow is represented as the superposition of infinite ring vortices properly arranged along the hub surface and the rotor wake. The solution is made explicit through a semi-analytical and iterative procedure. The proposed semi-analytical approach can deal with hubs of arbitrary shape and with quite general rotor load distributions. The method strongly couples the flow induced by the rotor and the hub. Moreover, the contraction/divergence and the rotation of the wake can be fully taken into account. The results of the semi-analytical method are also compared with those obtained with a widely diffused actuator disk model based on computational fluid dynamics (CFD) techniques. Finally, in comparison with more advanced methods, such as those relying on a CFD approach, this method is characterised by an extremely reduced computational cost. The computer code is freely available on contacting the authors.
Lifetime prevalence of non-suicidal self-injury in patients with eating disorders: a systematic review and meta-analysis
Authors: Cucchi A. , Ryan D. , Konstantakopoulos G. , Stroumpa S. , Kaçar A. Ş. , Renshaw S. , Landau S. , Kravariti E.
Published: March 2016

Background

Against a backdrop of increasing research, clinical and taxonomic attention in non-suicidal self-injury (NSSI), evidence suggests a link between NSSI and eating disorders (ED). The frequency estimates of NSSI in ED vary widely. Little is known about the sources of this variation, and no meta-analysis has quantified the association between ED and NSSI.

Method

Using random-effects meta-analyses, meta-regression analyses, and 1816–6466 unique participants with various ED, we estimated the weighted average percentage of individuals with ED, those with anorexia nervosa (AN) and those with bulimia nervosa (BN) who are reported to have a lifetime history of NSSI across studies. We further examined predictors of NSSI in ED.

Results

The weighted average percentage of patients with a lifetime history of NSSI was 27.3% [95% confidence interval (CI) 23.8–31.0%] for ED, 21.8% (95% CI 18.5–25.6%) for AN, and 32.7% (95% CI 26.9–39.1%) for BN. The difference between BN and AN was statistically significant [odds ratio (OR) 1.77, 95% CI 1.14–2.77, p = 0.013]. The odds of NSSI increased by 24% for every 10% increase in the percentage of participants with histories of suicide attempts (OR 1.24, 95% CI 1.04–1.48, p = 0.020) and decreased by 26% for every 10% increase in the percentage of participants with histories of substance abuse (OR 0.74, 95% CI 0.58–0.95, p = 0.023).

Conclusions

In the specific context of ED, NSSI is highly prevalent and correlates positively with attempted suicide, urging for NSSI-focused treatments. A novel finding is that NSSI is potentially antagonized by substance abuse.
Proposed OFDM Modulation for Future Generations of GNSS Signal System
Authors: He Ting , Ma Zherui
Published: March 2016

Modulation design has a significant effect on the accuracy of a navigation system. Two problems exist in current modulations for Global Navigation Satellite Systems (GNSS). One is the extremely low transmission rate of navigation messages. The other is the pseudorange error caused by multipath. To solve the restrictions, a novel GNSS signal system is proposed in this paper. In the new signal system, navigation messages are modulated by Orthogonal Frequency Division Multiplexing (OFDM) modulation for high transmission rate as well as excellent anti-multipath performance and conventional ranging code is still transmitted by Phase Shift Keying-Rectangular (PSK-R) or Binary Offset Carrier (BOC) modulation for precise ranging. Both the signal components supplement each other. Simulation results show that using the proposed GNSS signal system, stable and high transmission quality along with high transmission efficiency for navigation data are achieved. Also, the anti-multipath performance is significantly improved with less computational complexity.
Cerebellar Atrophy in Adult Survivors of Childhood Cerebellar Tumor
Authors: Ailion Alyssa S. , King Tricia Z. , Wang Liya , Fox Michelle, E. , Mao Hui , Morris Robin M. , Crosson Bruce
Published: March 2016

Objectives: The cerebellum (CB) is known for its role in supporting processing speed (PS) and cognitive efficiencies. The CB often sustains damage from treatment and resection in pediatric patients with posterior fossa tumors. Limited research suggests that CB atrophy may be associated with the radiation treatment experienced during childhood. The purpose of the study was to measure cerebellar atrophy to determine its neurobehavioral correlates. Methods: Brain magnetic resonance images were collected from 25 adult survivors of CB tumors and age- and gender-matched controls (Mage=24 years (SD=5), 52% female). Average age at diagnosis was 9 years (SD=5) and average time since diagnosis was 15 years (SD=5). PS was measured by the Symbol Digit Modality Test. To quantify atrophy, an objective formula was developed based on prior literature, in which Atrophy=[(CB White+CB Gray Volume)/Intracranial Vault (ICV)]controls-[(CB White+CB Gray+Lesion Size Volume)/ICV]survivors. Results: Regression analyses found that the interaction term (age at diagnosis*radiation) predicts CB atrophy; regression equations included the Neurological Predictor Scale, lesion size, atrophy, and the interaction term and accounted for 33% of the variance in oral PS and 48% of the variance in written PS. Both interactions suggest that individuals with smaller CB lesion size but a greater degree of CB atrophy had slower PS, whereas individuals with a larger CB lesion size and less CB atrophy were less affected. Conclusion: The results of the current study suggest that young age at diagnosis and radiation is associated with CB atrophy, which interacts with lesion size to impact both written and oral PS. (JINS, 2016, 23, 1–11)
Microstructural Characterization of Aluminum-Carbon Nanotube Nanocomposites Produced Using Different Dispersion Methods
Authors: Simões Sónia , Viana Filomena , Reis Marcos A. L. , Vieira Manuel F.
Published: March 2016

This research focuses on characterization of the impact of dispersion methods on aluminum-carbon nanotubes (Al-CNTs) nanocomposite structure. Nanocomposites were produced by a conventional powder metallurgy process after the dispersion of the CNTs on the Al powders, using two approaches: (1) the dispersion of CNTs and mixture with Al powders were performed in a single step by ultrasonication; and (2) the CNTs were previously untangled by ultrasonication and then mixed with Al powders by ball milling. Microstructural characterization of Al-CNT nanocomposites was performed by optical microscopy, scanning and transmission electron microscopy, electron backscatter diffraction, and high-resolution transmission electron microscopy (HRTEM). Microstructural characterization revealed that the use of ball milling for mixing CNTs with Al powders promoted the formation of CNT clusters of reduced size, more uniformly dispersed in the matrix, and a nanocomposite of smaller grain size. However, the results of HRTEM and Raman spectroscopy show that ball milling causes higher damage to the CNT structure. The strengthening effect of the CNT is attested by the increase in hardness and tensile strength of the nanocomposites.
Genetic polymorphisms among and between blast disease resistant and susceptible finger millet,Eleusine coracana(L.) Gaertn.
Authors: Saha Dipnarayan , Rana Rajeev Singh , Arya Lalit , Verma Manjusha , Gowda M. V. Channabyre , Upadhyaya Hari D.
Published: March 2016

Fungal blast disease is one of the major constraints in finger millet production. Breeding for disease resistance in finger millet, needs characterization of genetic polymorphism among and between the resistant and susceptible genotypes. In total, 67 finger millet genotypes, which are resistant or susceptible to fungal blast disease, were analysed using sequence-related amplified polymorphism (SRAP) and simple sequence repeat (SSR) markers to assess genetic variations and select diverse parents. Twelve each of SRAP and SSR primers produced 95.1 and 93.1% polymorphic bands and grouped them into unweighted pair-group method with arithmetic average clusters. Two of the finger millet genotypes, IE 4709 (blast resistant) and INDAF 7 (susceptible) were distinguished as most diverse genotypes as parents. Several genotype-specific bands observed with SSR primers are potential in developing genotype-specific markers. A high genetic diversity within the resistant and susceptible genotypes, rather than between them, was revealed through Nei's gene diversity (h) index and analysis of molecular variance. The finding helps us to understand the extent of genetic polymorphism between blast disease resistant and susceptible finger millet genotypes to exploit in resistance breeding programs.
Factors shaping the legal implications of increasingly autonomous military systems
Authors: McFarland Tim
Published: March 2016

This article identifies five factors that will shape the legal implications of the use of autonomous military systems. It contends that the systems which present legal challenges are those programmed to “make decisions” that are regulated by law. In so doing, they transfer control of, and responsibility for, those decisions away from those who have been traditionally seen as decision-makers to persons responsible for developing and deploying the system. The article also suggests that there may be limits to the extent to which the rules of international humanitarian law can appropriately regulate the altered relationship between soldiers and their increasingly autonomous weapon systems.
Depressivität und Kognition in der neuropsychologischen Rehabilitation nach Schlaganfall
Authors: Friedrich Melanie , Zimmermann Petra , Privou Caroline , Preier Michael , Kathrin Sackewitz-Barth  , Kauth Joachim , Gollas Margarete , Schubert Tanja , Lautenbacher Stefan
Published: March 2016

Zusammenfassung. Das Ziel der vorliegenden Untersuchung bestand darin, die Ausprägung und rehabilitative Relevanz von Depressivität nach Schlaganfall in der neuropsychologischen Versorgung prototypischer deutscher Neurorehabilitationseinrichtungen genauer zu beleuchten. Hierzu wurden 105 Schlaganfallpatienten aus zwei Kliniken untersucht. Der Depressivitätsgrad der Probanden wurde mit der Hamilton-Depressions-Skala erfasst, weiterhin wurden umfangreiche neuropsychologische Testbatterien durchgeführt. Etwa 15 % der Schlaganfallpatienten zeigten Hinweise auf eine leichte depressive Verstimmung. Der kognitive Status der Probanden konnte als für Schlaganfallpatienten typisch beschrieben werden, es ergaben sich jedoch keine Hinweise auf einen bei Poststroke Depression zu erwartenden kognitiven Status. Zudem zeigten sich sehr geringe Korrelationen der Hamilton-Depressions-Scores mit den Testleistungsparametern. Insgesamt legen die Studienergebnisse nahe, dass das Störungsbild der Poststroke Depression im Rahmen der stationären, neuropsychologischen Rehabilitation von eher untergeordneter Bedeutung ist.
Conserved regulators of Rag GTPases orchestrate amino acid-dependent TORC1 signaling
Authors: Powis Katie , De Virgilio Claudio
Published: March 2016

The highly conserved target of rapamycin complex 1 (TORC1) is the central component of a signaling network that couples a vast range of internal and external stimuli to cell growth, proliferation and metabolism. TORC1 deregulation is associated with a number of human pathologies, including many cancers and metabolic disorders, underscoring its importance in cellular and organismal growth control. The activity of TORC1 is modulated by multiple inputs; however, the presence of amino acids is a stimulus that is essential for its activation. Amino acid sufficiency is communicated to TORC1 via the highly conserved family of Rag GTPases, which assemble as heterodimeric complexes on lysosomal/vacuolar membranes and are regulated by their guanine nucleotide loading status. Studies in yeast, fly and mammalian model systems have revealed a multitude of conserved Rag GTPase modulators, which have greatly expanded our understanding of amino acid sensing by TORC1. Here we review the major known modulators of the Rag GTPases, focusing on recent mechanistic insights that highlight the evolutionary conservation and divergence of amino acid signaling to TORC1.
Regulatory (pan-)genome of an obligate intracellular pathogen in the PVC superphylum
Authors: de Barsy Marie , Frandi Antonio , Panis Gaël , Théraulaz Laurence , Pillonel Trestan , Greub Gilbert , Viollier Patrick H
Published: March 2016

Like other obligate intracellular bacteria, the Chlamydiae feature a compact regulatory genome that remains uncharted owing to poor genetic tractability. Exploiting the reduced number of transcription factors (TFs) encoded in the chlamydial (pan-)genome as a model for TF control supporting the intracellular lifestyle, we determined the conserved landscape of TF specificities by ChIP-Seq (chromatin immunoprecipitation-sequencing) in the chlamydial pathogen Waddlia chondrophila. Among 10 conserved TFs, Euo emerged as a master TF targeting >100 promoters through conserved residues in a DNA excisionase-like winged helix-turn-helix-like (wHTH) fold. Minimal target (Euo) boxes were found in conserved developmentally-regulated genes governing vertical genome transmission (cytokinesis and DNA replication) and genome plasticity (transposases). Our ChIP-Seq analysis with intracellular bacteria not only reveals that global TF regulation is maintained in the reduced regulatory genomes of Chlamydiae, but also predicts that master TFs interpret genomic information in the obligate intracellular α-proteobacteria, including the rickettsiae, from which modern day mitochondria evolved.
The microbiome of coral surface mucus has a key role in mediating holobiont health and survival upon disturbance
Authors: Glasl Bettina , Herndl Gerhard J , Frade Pedro R
Published: March 2016

Microbes are well-recognized members of the coral holobiont. However, little is known about the short-term dynamics of mucus-associated microbial communities under natural conditions and after disturbances, and how these dynamics relate to the host’s health. Here we examined the natural variability of prokaryotic communities (based on 16S ribosomal RNA gene amplicon sequencing) associating with the surface mucus layer (SML) of Porites astreoides, a species exhibiting cyclical mucus aging and shedding. Shifts in the prokaryotic community composition during mucus aging led to the prevalence of opportunistic and potentially pathogenic bacteria (Verrucomicrobiaceae and Vibrionaceae) in aged mucus and to a twofold increase in prokaryotic abundance. After the release of aged mucus sheets, the community reverted to its original state, dominated by Endozoicimonaceae and Oxalobacteraceae. Furthermore, we followed the fate of the coral holobiont upon depletion of its natural mucus microbiome through antibiotics treatment. After re-introduction to the reef, healthy-looking microbe-depleted corals started exhibiting clear signs of bleaching and necrosis. Recovery versus mortality of the P. astreoides holobiont was related to the degree of change in abundance distribution of the mucus microbiome. We conclude that the natural prokaryotic community inhabiting the coral SML contributes to coral health and that cyclical mucus shedding has a key role in coral microbiome dynamics.
Drift transport of helical spin coherence with tailored spin–orbit interactions
Authors: Kunihashi Y. , Sanada H. , Gotoh H. , Onomitsu K. , Kohda M. , Nitta J. , Sogawa T.
Published: March 2016

Most future information processing techniques using electron spins in non-magnetic semiconductors will require both the manipulation and transfer of spins without their coherence being lost. The spin–orbit effective magnetic field induced by drifting electrons enables us to rotate the electron spins in the absence of an external magnetic field. However, the fluctuations in the effective magnetic field originating from the random scattering of electrons also cause undesirable spin decoherence, which limits the length scale of the spin transport. Here we demonstrate the drift transport of electron spins adjusted to a robust spin structure, namely a persistent spin helix. We find that the persistent spin helix enhances the spatial coherence of drifting spins, resulting in maximized spin decay length near the persistent spin helix condition. Within the enhanced distance of the spin transport, the transport path of electron spins can be modulated by employing time-varying in-plane voltages.
Extinction of fish-shaped marine reptiles associated with reduced evolutionary rates and global environmental volatility
Authors: Fischer Valentin , Bardet Nathalie , Benson Roger B. J. , Arkhangelsky Maxim S. , Friedman Matt
Published: March 2016

Despite their profound adaptations to the aquatic realm and their apparent success throughout the Triassic and the Jurassic, ichthyosaurs became extinct roughly 30 million years before the end-Cretaceous mass extinction. Current hypotheses for this early demise involve relatively minor biotic events, but are at odds with recent understanding of the ichthyosaur fossil record. Here, we show that ichthyosaurs maintained high but diminishing richness and disparity throughout the Early Cretaceous. The last ichthyosaurs are characterized by reduced rates of origination and phenotypic evolution and their elevated extinction rates correlate with increased environmental volatility. In addition, we find that ichthyosaurs suffered from a profound Early Cenomanian extinction that reduced their ecological diversity, likely contributing to their final extinction at the end of the Cenomanian. Our results support a growing body of evidence revealing that global environmental change resulted in a major, temporally staggered turnover event that profoundly reorganized marine ecosystems during the Cenomanian.
Anomalous correlation effects and unique phase diagram of electron-doped FeSe revealed by photoemission spectroscopy
Authors: Wen C. H. P. , Xu H. C. , Chen C. , Huang Z. C. , Lou X. , Pu Y. J. , Song Q. , Xie B. P. , Abdel-Hafiez Mahmoud , Chareev D. A. , Vasiliev A. N. , Peng R. , Feng D. L.
Published: March 2016

FeSe layer-based superconductors exhibit exotic and distinctive properties. The undoped FeSe shows nematicity and superconductivity, while the heavily electron-doped KxFe2−ySe2 and single-layer FeSe/SrTiO3 possess high superconducting transition temperatures that pose theoretical challenges. However, a comprehensive study on the doping dependence of an FeSe layer-based superconductor is still lacking due to the lack of a clean means of doping control. Through angle-resolved photoemission spectroscopy studies on K-dosed thick FeSe films and FeSe0.93S0.07 bulk crystals, here we reveal the internal connections between these two types of FeSe-based superconductors, and obtain superconductivity below ∼46 K in an FeSe layer under electron doping without interfacial effects. Moreover, we discover an exotic phase diagram of FeSe with electron doping, including a nematic phase, a superconducting dome, a correlation-driven insulating phase and a metallic phase. Such an anomalous phase diagram unveils the remarkable complexity, and highlights the importance of correlations in FeSe layer-based superconductors.
Manipulation of prenylation reactions by structure-based engineering of bacterial indolactam prenyltransferases
Authors: Mori Takahiro , Zhang Lihan , Awakawa Takayoshi , Hoshino Shotaro , Okada Masahiro , Morita Hiroyuki , Abe Ikuro
Published: March 2016

Prenylation reactions play crucial roles in controlling the activities of biomolecules. Bacterial prenyltransferases, TleC from Streptomyces blastmyceticus and MpnD from Marinactinospora thermotolerans, catalyse the ‘reverse’ prenylation of (−)-indolactam V at the C-7 position of the indole ring with geranyl pyrophosphate or dimethylallyl pyrophosphate, to produce lyngbyatoxin or pendolmycin, respectively. Using in vitro analyses, here we show that both TleC and MpnD exhibit relaxed substrate specificities and accept various chain lengths (C5–C25) of the prenyl donors. Comparisons of the crystal structures and their ternary complexes with (−)-indolactam V and dimethylallyl S-thiophosphate revealed the intimate structural details of the enzyme-catalysed ‘reverse’ prenylation reactions and identified the active-site residues governing the selection of the substrates. Furthermore, structure-based enzyme engineering successfully altered the preference for the prenyl chain length of the substrates, as well as the regio- and stereo-selectivities of the prenylation reactions, to produce a series of unnatural novel indolactams.
Using mutability landscapes of a promiscuous tautomerase to guide the engineering of enantioselective Michaelases
Authors: van der Meer Jan-Ytzen , Poddar Harshwardhan , Baas Bert-Jan , Miao Yufeng , Rahimi Mehran , Kunzendorf Andreas , van Merkerk Ronald , Tepper Pieter G. , Geertsema Edzard M. , Thunnissen Andy-Mark W. H. , Quax Wim J. , Poelarends Gerrit J.
Published: March 2016

The Michael-type addition reaction is widely used in organic synthesis for carbon–carbon bond formation. However, biocatalytic methodologies for this type of reaction are scarce, which is related to the fact that enzymes naturally catalysing carbon–carbon bond-forming Michael-type additions are rare. A promising template to develop new biocatalysts for carbon–carbon bond formation is the enzyme 4-oxalocrotonate tautomerase, which exhibits promiscuous Michael-type addition activity. Here we present mutability landscapes for the expression, tautomerase and Michael-type addition activities, and enantioselectivity of 4-oxalocrotonate tautomerase. These maps of neutral, beneficial and detrimental amino acids for each residue position and enzyme property provide detailed insight into sequence–function relationships. This offers exciting opportunities for enzyme engineering, which is illustrated by the redesign of 4-oxalocrotonate tautomerase into two enantiocomplementary ‘Michaelases’. These ‘Michaelases’ catalyse the asymmetric addition of acetaldehyde to various nitroolefins, providing access to both enantiomers of γ-nitroaldehydes, which are important precursors for pharmaceutically active γ-aminobutyric acid derivatives.
A general approach to visualize protein binding and DNA conformation without protein labelling
Authors: Song Dan , Graham Thomas G. W. , Loparo Joseph J.
Published: March 2016

Single-molecule manipulation methods, such as magnetic tweezers and flow stretching, generally use the measurement of changes in DNA extension as a proxy for examining interactions between a DNA-binding protein and its substrate. These approaches are unable to directly measure protein–DNA association without fluorescently labelling the protein, which can be challenging. Here we address this limitation by developing a new approach that visualizes unlabelled protein binding on DNA with changes in DNA conformation in a relatively high-throughput manner. Protein binding to DNA molecules sparsely labelled with Cy3 results in an increase in fluorescence intensity due to protein-induced fluorescence enhancement (PIFE), whereas DNA length is monitored under flow of buffer through a microfluidic flow cell. Given that our assay uses unlabelled protein, it is not limited to the low protein concentrations normally required for single-molecule fluorescence imaging and should be broadly applicable to studying protein–DNA interactions.
Lithium Protects Against Anaesthesia Neurotoxicity In The Infant Primate Brain
Authors: Noguchi Kevin K. , Johnson Stephen A. , Kristich Lauren E. , Martin Lauren D. , Dissen Gregory A. , Olsen Emily A. , Olney John W. , Brambrink Ansgar M.
Published: March 2016

Exposure of infant animals, including non-human primates (NHPs), to anaesthetic drugs causes apoptotic death of neurons and oligodendrocytes (oligos) and results in long-term neurodevelopmental impairment (NDI). Moreover, retrospective clinical studies document an association between anaesthesia exposure of human infants and significant increase in NDI. These findings pose a potentially serious dilemma because millions of human infants are exposed to anaesthetic drugs every year as part of routine medical care. Lithium (Li) at clinically established doses is neuroprotective in various cerebral injury models. We therefore investigated whether Li also protects against anaesthesia neurotoxicity in infant NHPs. On postnatal day 6 NHPs were anaesthetized with the widely used anaesthetic isoflurane (ISO) for 5 h employing the same standards as in a human pediatric surgery setting. Co-administration of Li completely prevented the acute ISO-induced neuroapoptosis and significantly reduced ISO-induced apoptosis of oligodendroglia. Our findings are highly encouraging as they suggest that a relatively simple pharmacological manipulation might protect the developing primate brain against the neurotoxic action of anaesthetic drugs while not interfering with the beneficial actions of these drugs. Further research is needed to determine Li’s potential to prevent long-term NDI resulting from ISO anaesthesia and to establish its safety in human infants.
Tropical secondary forests regenerating after shifting cultivation in the Philippines uplands are important carbon sinks
Authors: Mukul Sharif A. , Herbohn John , Firn Jennifer
Published: March 2016

In the tropics, shifting cultivation has long been attributed to large scale forest degradation, and remains a major source of uncertainty in forest carbon accounting. In the Philippines, shifting cultivation, locally known as kaingin, is a major land-use in upland areas. We measured the distribution and recovery of aboveground biomass carbon along a fallow gradient in post-kaingin secondary forests in an upland area in the Philippines. We found significantly higher carbon in the aboveground total biomass and living woody biomass in old-growth forest, while coarse dead wood biomass carbon was higher in the new fallow sites. For young through to the oldest fallow secondary forests, there was a progressive recovery of biomass carbon evident. Multivariate analysis indicates patch size as an influential factor in explaining the variation in biomass carbon recovery in secondary forests after shifting cultivation. Our study indicates secondary forests after shifting cultivation are substantial carbon sinks and that this capacity to store carbon increases with abandonment age. Large trees contribute most to aboveground biomass. A better understanding of the relative contribution of different biomass sources in aboveground total forest biomass, however, is necessary to fully capture the value of such landscapes from forest management, restoration and conservation perspectives.
Quantitative proteomics study of the neuroprotective effects of B12 on hydrogen peroxide-induced apoptosis in SH-SY5Y cells
Authors: Zhong Lijun , Zhou Juntuo , Chen Xi , Lou Yaxin , Liu Dan , Zou Xiajuan , Yang Bin , Yin Yuxin , Pan Yan
Published: March 2016

B12 belongs to the coumarin class of compounds that have been shown to have various physiological and pharmacological activities including anti-inflammatory, antibacterial and antioxidant. In the present study, we characterised the neuroprotective effects of B12 against H2O2-induced neuronal cell damage in SH-SY5Y cells. Protein expression profiling in combination with pathway analysis was deployed to investigate the molecular events associated with the neuroprotective effects in human neuronal cells using a label-free quantitative proteomics approach. A total of 22 proteins were significantly differentially expressed in H2O2-damaged cells with or without B12 treatment. Bioinformatics analysis using the Cytoscape platform indicated that poly pyrimidine tract binding protein 1 (PTBP1) was highly associated with the protective effect and western blotting verified that PTBP1 was up-regulated in H2O2 + B12 treatment group, compared with the H2O2 treated group. PTBP RNAi experiments knocked down PTBP expression, which cancelled out the protective effect of B12 on cell viability. Thus, we infer that B12 neuroprotective activity involves up-regulation of PTBP1 and its associated signalling networks following H2O2-induced apoptosis in SH-SY5Y cells. B12 or related compounds may prove to be useful therapeutic agents for the treatment of neurodegenerative diseases such as Alzheimer’s and Parkinson’s.
Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives
Authors: Wang Hongdong , Liu Yuhong , Chen Zhe , Wu Bibo , Xu Sailong , Luo Jianbin
Published: March 2016

High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application.
Evolutionary Dynamics of Homophily and Heterophily
Authors: Ramazi Pouria , Cao Ming , Weissing Franz J.
Published: March 2016

Most social interactions do not take place at random. In many situations, individuals choose their interaction partners on the basis of phenotypic cues. When this happens, individuals are often homophilic, that is, they tend to interact with individuals that are similar to them. Here we investigate the joint evolution of phenotypic cues and cue-dependent interaction strategies. By a combination of individual-based simulations and analytical arguments, we show that homophily evolves less easily than earlier studies suggest. The evolutionary interplay of cues and cue-based behaviour is intricate and has many interesting facets. For example, an interaction strategy like heterophily may stably persist in the population even if it is selected against in association with any particular cue. Homophily persisted for extensive periods of time just in those simulations where homophilic interactions provide a lower (rather than a higher) payoff than heterophilic interactions. Our results indicate that even the simplest cue-based social interactions can have rich dynamics and a surprising diversity of evolutionary outcomes.