bluuebunny/crossref_metadata_2025 huggingface dataset:
Tunable hard x-ray source from obliquely incident intense laser interacting with overdense solid targets
Authors: Pan K. Q. , Zheng C. Y. , Wu Dong , He X. T.
Published: August 2015

A tunable hard x-ray source from intense laser interacting with overdense solid targets is proposed. It is shown that the incident angle of the laser plays an important role in influencing the radiation quality, including the spectrum of the radiation, the energy conversion efficiency from laser to radiation, and the angular distribution of the radiation. The two dimensional relativistic particle-in-cell simulations shows that, to get the highest energy conversion efficiency, the optimal incident angle for the present simulation parameters is 30°, and the energy conversion efficiency from laser to radiation in the optimal incident angle is about 5%, which is far more efficient than other incidence condition using the same laser pulse. The intensity of the laser used in the simulation is 1.34×1022 W/cm2. Detailed analysis shows that the vacuum heating radiation mechanism is the dominant mechanism responsible for hard x-ray emission, and the radiation frequency spectrum is tunable when the incident angle changes.
Aspects of the Eckart frame ro-vibrational kinetic energy operator
Authors: Szalay Viktor
Published: August 2015

A most decisive part of developing the Eckart frame ro-vibrational kinetic energy operator (KEO) in terms of curvilinear internal coordinates is the introduction of vibrational displacements obeying the Eckart conditions. It is examined here, how such displacements may be constructed by orthogonal and nonorthogonal transformations, and how they can be employed in developing the KEO. In particular, it is shown analytically, by term by term comparison, that the Eckart KEOs obtained by employing Pickett’s method and the gateway Hamiltonian method are equivalent. That is, although it may appear in the form of very different expressions, the general, exact ro-vibrational Eckart frame KEO is unique. As side result, it has been shown that the simple formula of the pseudo-potential derived by Watson for the exact KEO given in normal coordinates applies to any Eckart frame KEO, irrespective of the choice of the vibrational coordinates.
Enhance the terahertz Smith-Purcell superradiant radiation by using dielectric loaded grating
Authors: Cao Miaomiao , Liu Wenxin , Wang Yong , Li Ke
Published: August 2015

A dielectric loaded grating (DLG) for terahertz Smith-Purcell (SP) device is proposed to enhance the radiation intensity. By using the theoretical analysis and particle-in-cell simulations, the dispersion characteristics and SP superradiant radiation are investigated. Compared with the general metal grating, the usage of DLG can improve the magnitude of electric field and, consequently, strengthen the interaction of the evanescent wave with electron beam, which can improve the growth rate, enhance the SP superradiant radiation, and lower the start current for the operation of SP free-electron laser.
Size, shape, and diffusivity of a single Debye-Hückel polyelectrolyte chain in solution
Authors: Soysa W. Chamath , Dünweg B. , Prakash J. Ravi
Published: August 2015

Brownian dynamics simulations of a coarse-grained bead-spring chain model, with Debye-Hückel electrostatic interactions between the beads, are used to determine the root-mean-square end-to-end vector, the radius of gyration, and various shape functions (defined in terms of eigenvalues of the radius of gyration tensor) of a weakly charged polyelectrolyte chain in solution, in the limit of low polymer concentration. The long-time diffusivity is calculated from the mean square displacement of the centre of mass of the chain, with hydrodynamic interactions taken into account through the incorporation of the Rotne-Prager-Yamakawa tensor. Simulation results are interpreted in the light of the Odjik, Skolnick, Fixman, Khokhlov, and Khachaturian blob scaling theory (Everaers et al., Eur. Phys. J. E 8, 3 (2002)) which predicts that all solution properties are determined by just two scaling variables—the number of electrostatic blobs X and the reduced Debye screening length, Y. We identify three broad regimes, the ideal chain regime at small values of Y, the blob-pole regime at large values of Y, and the crossover regime at intermediate values of Y, within which the mean size, shape, and diffusivity exhibit characteristic behaviours. In particular, when simulation results are recast in terms of blob scaling variables, universal behaviour independent of the choice of bead-spring chain parameters, and the number of blobs X, is observed in the ideal chain regime and in much of the crossover regime, while the existence of logarithmic corrections to scaling in the blob-pole regime leads to non-universal behaviour.
Electronic structure investigation of atomic layer deposition ruthenium(oxide) thin films using photoemission spectroscopy
Authors: Schaefer Michael , Schlaf Rudy
Published: August 2015

Analyzing and manipulating the electronic band line-up of interfaces in novel micro- and nanoelectronic devices is important to achieve further advancement in this field. Such band alignment modifications can be achieved by introducing thin conformal interfacial dipole layers. Atomic layer deposition (ALD), enabling angstrom-precise control over thin film thickness, is an ideal technique for this challenge. Ruthenium (Ru0) and its oxide (RuO2) have gained interest in the past decade as interfacial dipole layers because of their favorable properties like metal-equivalent work functions, conductivity, etc. In this study, initial results of the electronic structure investigation of ALD Ru0 and RuO2 films via photoemission spectroscopy are presented. These experiments give insight into the band alignment, growth behavior, surface structure termination, and dipole formation. The experiments were performed in an integrated vacuum system attached to a home-built, stop-flow type ALD reactor without exposing the samples to the ambient in between deposition and analysis. Bis(ethylcyclopentadienyl)ruthenium(II) was used as precursor and oxygen as reactant. The analysis chamber was outfitted with X-ray photoemission spectroscopy (LIXPS, XPS). The determined growth modes are consistent with a strong growth inhibition situation with a maximum average growth rate of 0.21 Å/cycle for RuO2 and 0.04 Å/cycle for Ru.0 An interface dipole of up to −0.93 eV was observed, supporting the assumption of a strongly physisorbed interface. A separate experiment where the surface of a RuO film was sputtered suggests that the surface is terminated by an intermediate, stable, non-stoichiometric RuO2/OH compound whose surface is saturated with hydroxyl groups.
Occurrence of magnetoelectric effect correlated to the Dy order in Dy2NiMnO6 double perovskite
Authors: Masud Md G. , Dey K. , Ghosh A. , Majumdar S. , Giri S.
Published: August 2015

Magnetic, dielectric, and ac conductivity as well as room temperature structural and Raman studies are performed on double perovskite Dy2NiMnO6. The crystal structure of the compound adopts monoclinic P21/n space group, where alternate Mn and Ni distorted octahedral are arranged in anti-phase a− a− b+ order in Glazer notation. Magnetization studies show two magnetic transitions around 100 K and 20 K which are related to the ordering of transition and rare earth cations moment, respectively. Temperature dependent dielectric permittivity shows Havriliak-Negami type thermally activated dielectric relaxation. The ac conductivity at different temperature is found to follow Jonscher power law behavior. Time-temperature scaling of the conductivity spectra reveals that the charge transport dynamics is independent of temperature. Intriguingly, an anomaly in the dielectric constant is observed close to the order of Dy moment which indicates intrinsic magnetoelectric coupling. The hybridization between Dy and Ni/Mn is suggested to be correlated with the magnetoelectric coupling.
Violation of adiabaticity in magnetic billiards due to separatrix crossings
Authors: Artemyev A. V. , Neishtadt A. I.
Published: August 2015

We consider dynamics of magnetic billiards with curved boundaries and strong inhomogeneous magnetic field. We investigate a violation of adiabaticity of charged particle motion in this system. The destruction of the adiabatic invariance is due to the change of type of the particle trajectory: particles can drift along the boundary reflecting from it or rotate around the magnetic field at some distance from the boundary without collisions with it. Trajectories of these two types are demarcated in the phase space by a separatrix. Crossings of the separatrix result in jumps of the adiabatic invariant. We derive an asymptotic formula for such a jump and demonstrate that an accumulation of these jumps leads to the destruction of the adiabatic invariance.
Ultra-sensitive pressure dependence of bandgap of rutile-GeO2 revealed by many body perturbation theory
Authors: Samanta Atanu , Jain Manish , Singh Abhishek K.
Published: August 2015

The reported values of bandgap of rutile GeO2 calculated by the standard density functional theory within local-density approximation (LDA)/generalized gradient approximation (GGA) show a wide variation (∼2 eV), whose origin remains unresolved. Here, we investigate the reasons for this variation by studying the electronic structure of rutile-GeO2 using many-body perturbation theory within the GW framework. The bandgap as well as valence bandwidth at Γ-point of rutile phase shows a strong dependence on volume change, which is independent of bandgap underestimation problem of LDA/GGA. This strong dependence originates from a change in hybridization among O-p and Ge-(s and p) orbitals. Furthermore, the parabolic nature of first conduction band along X-Γ-M direction changes towards a linear dispersion with volume expansion.
Coexistence of electric field controlled ferromagnetism and resistive switching for TiO2 film at room temperature
Authors: Ren Shaoqing , Qin Hongwei , Bu Jianpei , Zhu Gengchang , Xie Jihao , Hu Jifan
Published: August 2015

The Ag/TiO2/Nb:SrTiO3/Ag device exhibits the coexistence of electric field controlled ferromagnetism and resistive switching at room temperature. The bipolar resistive switching in Ag/TiO2/Nb:SrTiO3/Ag device may be dominated by the modulation of Schottky-like barrier with the electron injection-trapped/detrapped process at the interface of TiO2/Nb:SrTiO3. We suggest that the electric field-induced magnetization modulation originates mainly from the creation/annihilation of lots of oxygen vacancies in TiO2.
Compositional bowing of band energies and their deformation potentials in strained InGaAs ternary alloys: A first-principles study
Authors: Khomyakov Petr A. , Luisier Mathieu , Schenk Andreas
Published: August 2015

Using first-principles calculations, we show that the conduction and valence band energies and their deformation potentials exhibit a non-negligible compositional bowing in strained ternary semiconductor alloys such as InGaAs. The electronic structure of these compounds has been calculated within the framework of local density approximation and hybrid functional approach for large cubic supercells and special quasi-random structures, which represent two kinds of model structures for random alloys. We find that the predicted bowing effect for the band energy deformation potentials is rather insensitive to the choice of the functional and alloy structural model. The direction of bowing is determined by In cations that give a stronger contribution to the formation of the InxGa1−xAs valence band states with x ≳ 0.5, compared to Ga cations.
Optimizing design of irradiation uniformity of direct drive cone-in-shell target for fast ignition
Authors: Tian Chao , Shan Lianqiang , Zhou Weimin , Liu Dongxiao , Bi Bi , Zhang Feng , Wang Weiwu , Gu Yuqiu , Zhang Baohan
Published: August 2015

The irradiation uniformity of a cone-in-shell target directly driven by laser beams has been considered. First, a model is established to include the influence of the cone on laser beam propagation. Then, the irradiation uniformity on the target surface outside the cone during the initial imprinting phase is analyzed, and highly uniform irradiation on the target surface outside the cone is achieved by optimizing the intensity distribution within laser beams, as well as the polar direct drive displacement. As an illustrative example, direct drive irradiation uniformity of a typical cone-in-shell target is improved for Shenguang III laser facility, the illumination non-uniformity is reduced from 5.8% to 1.1%. Irradiation on the cone surface outside the target is also analyzed, and it is found that for the laser-target configuration considered in this work, a gold cone thicker than 50μm is needed to avoid shock breakout. Moreover, sensitivity to beam uncertainties (power imbalance and pointing error) is analyzed, indicating that this scheme can tolerate a certain amount of beam errors.
Maximal charge injection of consecutive electron pulses with uniform temporal pulse separation
Authors: Liu Y. L. , Zhang P. , Chen S. H. , Ang L. K.
Published: August 2015

A charge sheet model is proposed for the study of the space-charge limited density of consecutive electron pulses injected to in a diode with uniform temporal pulse separation. Based on the model, an analytical formula is derived for expressing the dependency of the charge density limit on the gap spacing, gap voltage, and pulse separation. The theoretical results are verified by numerical solutions up to electron energy of a few MeV, including relativistic effects. The model can be applied to the design of multiple-pulse electron beams for time resolved electron microscopy and free electron lasers.
Influence of coherent optical phonon on ultrafast energy relaxation
Authors: Wang J. L. , Guo L. , Liu C. H. , Xu X. , Chen Y. F.
Published: August 2015

Ultrafast energy relaxation process in Bi2Te3 thin films is studied using a collinear two color pump-probe technique. The coherent optical phonon is enhanced and destroyed by changing the separation times of double pump pulses. The non-oscillatory component of the reflectivity trace after the second pump pulse shows a distinct difference with and without the presence of coherent optical phonons, thus providing a direct evidence of the effect of optical phonon on the hot carrier relaxation process. The deduced characteristic times are systematically smaller when coherent optical phonons are involved in the energy transfer process. Comparatively, the conventional relaxation process is relatively slow, which is explained by the screening effect of the incoherent optical phonon. This work suggests that the energy relaxation can be manipulated through the excitation of coherent optical phonons.
Tracking the formation of methylammonium lead triiodide perovskite
Authors: Liu Lijia , McLeod John A. , Wang Rongbin , Shen Pengfei , Duhm Steffen
Published: August 2015

The formation mechanism of perovskite methylammonium lead triiodide (CH3NH3PbI3) was studied with in situ X-ray photoelectron spectroscopy (XPS) on successive depositions of thermally evaporated methylammonium iodide (CH3NH3I) on a lead iodide (PbI2) film. This deposition method mimics the “two-step” synthesis method commonly used in device fabrication. We find that several competing processes occur during the formation of perovskite CH3NH3PbI3. Our most important finding is that during vapour deposition of CH3NH3I onto PbI2, at least two carbon species are present in the resulting material, while only one nitrogen species is present. This suggests that CH3NH3I can dissociate during the transition to a perovskite phase, and some of the resulting molecules can be incorporated into the perovskite. The effect of partial CH3NH3 substitution with CH3 was evaluated, and electronic structure calculations show that CH3 defects would impact the photovoltaic performance in perovskite solar cells. The possibility that not all A sites in the APbI3 perovskite are occupied by CH3NH3 is therefore an important consideration when evaluating the performance of organometallic trihalide solar cells synthesized using typical approaches.
Thermal and strain-stiffening effects on the electromechanical breakdown strength of dielectric elastomers
Authors: Liu Lei , Chen Hualing , Li Bo , Wang Yanjie , Li Dichen
Published: August 2015

The electromechanical breakdown strength determines the limit of a dielectric elastomer for its use in actuators and energy harvesters. We investigated experimentally and theoretically the thermal and strain-stiffening effects on the electromechanical breakdown strength. The stain-stiffening induced by large stretch highly enhance the maximum energy density and breakdown strength. A temperature dependence of breakdown strength is consistent with the electromechanical breakdown model by taking into account of the strain-stiffness effect of dielectric elastomer. Furthermore, the stain-stiffening also increases the thermal sensitivity of breakdown strength.
Scalable synthesis of sequence-defined, unimolecular macromolecules by Flow-IEG
Authors: Leibfarth Frank A. , Johnson Jeremiah A. , Jamison Timothy F.
Published: August 2015

Significance

Automated chemical processes, such as DNA sequencing and nucleic acid and peptide synthesis, have transformed the fields of genetics and biotechnology. There is no analogous automated or semiautomated process, however, to provide unimolecular, sequence-defined synthetic polymers to those interested in studying them. The combination of multistep continuous flow chemistry and polymer synthesis by iterative exponential growth (Flow-IEG) enables the semiautomated synthesis of perfect polymers reported herein. The user-friendly nature, scalability, and modularity of Flow-IEG provides a general strategy for the automated synthesis of sequence and architecturally defined, uniform macromolecules. We envision this polymer synthesis machine will serve as an enabling tool for both fundamental explorations and advanced applications in biotechnology, medicinal chemistry, and materials science.
Association of Brachial–Ankle Pulse Wave Velocity With Cardiovascular
Events in Atrial Fibrillation
Authors: Chen Szu-Chia , Lee Wen-Hsien , Hsu Po-Chao , Lin Ming-Yen , Lee Chee-Siong , Lin Tsung-Hsien , Voon Wen-Chol , Lai Wen-Ter , Sheu Sheng-Hsiung , Su Ho-Ming
Published: August 2015

BACKGROUND

Atrial fibrillation (AF) and increased arterial stiffness share several risk factors and the 2 diseases often coexist. However, the prognostic value of increased arterial stiffness remains uncertain in the AF population. We evaluated whether brachial–ankle pulse wave velocity (baPWV), a marker of arterial stiffness, can predict cardiovascular events, and determined that the baPWV is a more favorable prognostic marker compared with conventional clinical and echocardiographic markers in patients with AF.

METHODS

We enrolled 167 patients with persistent AF. Arterial stiffness was assessed using baPWV. Cardiovascular events were defined as cardiovascular death, nonfatal stroke, nonfatal myocardial infarction, and hospitalization for heart failure. The relative risk of cardiovascular events was analyzed using Cox regression models. An improvement in model prediction was determined using the –2 log likelihood ratio statistic.

RESULTS

During a median 26-month follow-up, 42 (24.9%) cardiovascular events were observed. The baPWV emerged as an independent predictor of cardiovascular events (adjusted hazard ratio: 1.152; 95% confidence interval: 1.054–1.259; P = 0.002) in the multivariate analysis. Furthermore, the addition of baPWV to a Cox model comprising standard clinical, biochemical, and echocardiographic parameters improved the prediction of adverse cardiovascular events ( P < 0.001).

CONCLUSIONS

In patients with AF, a high baPWV is associated with increased cardiovascular events and improve the prediction of adverse cardiovascular events. Hence, baPWV might be included when examining patients with AF for prediction of adverse cardiovascular outcomes.
The Stress and Mood Management Program for Individuals With Multiple Sclerosis
Authors: Mohr David
Published: August 2015

Multiple Sclerosis presents not only physical challenges, but emotional challenges as well. Many people with MS suffer from depression, anxiety and stress. Problems with mood and stress can interfere with relationships with others, reduce ability to meet obligations at work and at home, and substantially worsen overall quality of life. The stress and mood management program described in this book is backed by research and has proven effective in clinical trials. Based on the principles of cognitive-behavioral therapy (CBT), one of the most effective therapeutic techniques available for combating depression and anxiety, this program can help manage stress and improve well-being. It provides ways to learn skills for identifying and challenging your unhelpful thoughts, as well as how to motivate to reengage in pleasant activities. It also covers treatment modules that can be modified to specific MS-related problems. Choices include modules on managing symptoms like fatigue, pain, and cognitive problems, and improving communication and assertiveness skills, among others. It also provides a module on self-injection anxiety.
Introduction to Stress and Mood Management
Authors: Mohr David C.
Published: August 2015

Chapter 1 outlines the introductory session of the stress and mood management program for MS, including rating stress levels, goals and structure for the program, the collaborative relationship in therapy, rationale for stress and mood management for MS, where distress, mood problems, and stress come from, and the stress and mood management model.
Positive Activities
Authors: Mohr David C.
Published: August 2015

Chapter 3 discusses positive activities, the importance of including positive activities in plans, the relationship between activities and mood, activity diaries, scheduling positive activities, and noticing positive events.
Identifying and Evaluating your Unhelpful Thoughts
Authors: Mohr David C.
Published: August 2015

Chapter 4 discusses the identification and evaluation of unhelpful thoughts. It describes automatic thoughts, the importance of awareness, the use of an unhelpful thought diary (UTD), the strength of emotions and physical symptoms, as well as negative thought patterns and how to identify them.
Module 2: Fatigue and Energy Conservation
Authors: Mohr David C.
Published: August 2015

This chapter describes an optional treatment module on fatigue and energy conservation. It discusses MS fatigue, types of fatigue (normal fatigue, fatigue from depression and stress, disability fatigue, deconditioning fatigue, fatigue from sleep disturbance, heat-related fatigue, fatigue from diet problems, and primary MS fatigue), and methods for coping with fatigue.
Module 3: Reducing Anxiety and Worry
Authors: Mohr David C.
Published: August 2015

This chapter describes an optional treatment module on reducing anxiety and worry. It explores signs of excessive worry, the risk/resource ratio, real alarms versus false alarms, and techniques to manage anxiety and worry (determining the real risk, evaluate coping resources, estimate probability, reduce physical tension, postponing worry and scheduling worry time).
Module 6: Planning and Organization
Authors: Mohr David C.
Published: August 2015

This chapter describes an optional treatment module on planning and organization. It discusses why planning and organization are important, cognitive problems in MS, using an organizer, to-do lists, realistic daily goals and planning for bigger jobs, obstacles that interfere with planning and organization (attention and concentration problems, negative emotional reactions) and other organizational tips.
Module 8: Ending Treatment and Maintaining Gains
Authors: Mohr David C.
Published: August 2015

This chapter describes an optional treatment module on ending treatment and maintaining gains. This includes a review of the strategies and techniques that have been learned, common reactions to ending the weekly meetings and therapy overall, developing a stress management plan, and useful resources.
Prognostic Value of Ki-67 Labeling Index and Postoperative Radiotherapy in WHO Grade II Meningioma
Authors: Choi Yunseon , Lim Do Hoon , Yu Jeong Il , Jo Kyungil , Nam Do-Hyun , Seol Ho Jun , Lee Jung-Il , Kong Doo-Sik , Suh Yeon-Lim , Nam Heerim
Published: August 2015

Objective:

This study was performed to determine the clinical significance of the Ki-67 labeling index (LI) for local control (LC) in patients with World Health Organization (WHO) grade II meningioma. We also tried to discern the effect of postoperative radiotherapy (PORT) on LC depending upon the Ki-67 LI value.

Materials and Methods:

The medical records and values of Ki-67 LIs were retrospectively reviewed for 50 patients who underwent surgical resection of intracranial WHO grade II meningiomas at Samsung Medical Center from May 2001 to December 2012. Forty-three patients (86%) were treated with immediate PORT. The median total radiation dose was 60 Gy (range, 54 to 60 Gy).

Results:

The median follow-up was 47.4 months. The mean Ki-67 LI was 13% (range, 1% to 47%). Twelve patients (24.0%) showed local failure, and 8 patients (16.0%) experienced local failure even after PORT. The mean Ki-67 LI was 15% in patients with local failure (n=12) and 12% in patients without local failure (n=38). The 3-year actuarial LC was 80.5%. The 3-year overall survival was 89.5%. Ki-67 LI>13% and PORT were significant prognostic factors for LC (P=0.015 and 0.009, respectively). In patients with Ki-67 LI>13% (n=17), PORT (n=14) improved LC (P<0.001). However, PORT (n=29) did not affect LC (P=0.412) for patients with Ki-67 LI≤13% (n=33).

Conclusions:

Ki-67 LI can be a useful prognostic factor for LC in WHO grade II meningioma. In patients with Ki-67 LI>13%, PORT should be recommended to improve LC.
Plasmid carriage can limit bacteria–phage coevolution
Authors: Harrison Ellie , Truman Julie , Wright Rosanna , Spiers Andrew J. , Paterson Steve , Brockhurst Michael A.
Published: August 2015

Coevolution with bacteriophages is a major selective force shaping bacterial populations and communities. A variety of both environmental and genetic factors has been shown to influence the mode and tempo of bacteria–phage coevolution. Here, we test the effects that carriage of a large conjugative plasmid, pQBR103, had on antagonistic coevolution between the bacterium
Pseudomonas fluorescens
and its phage, SBW25
ϕ
2. Plasmid carriage limited bacteria–phage coevolution; bacteria evolved lower phage-resistance and phages evolved lower infectivity in plasmid-carrying compared with plasmid-free populations. These differences were not explained by effects of plasmid carriage on the costs of phage resistance mutations. Surprisingly, in the presence of phages, plasmid carriage resulted in the evolution of high frequencies of mucoid bacterial colonies. Mucoidy can provide weak partial resistance against SBW25
ϕ
2, which may have limited selection for qualitative resistance mutations in our experiments. Taken together, our results suggest that plasmids can have evolutionary consequences for bacteria that go beyond the direct phenotypic effects of their accessory gene cargo.
Phenotype–environment matching in sand fleas
Authors: Stevens Martin , Broderick Annette C. , Godley Brendan J. , Lown Alice E. , Troscianko Jolyon , Weber Nicola , Weber Sam B.
Published: August 2015

Camouflage is perhaps the most widespread anti-predator strategy in nature, found in numerous animal groups. A long-standing prediction is that individuals should have camouflage tuned to the visual backgrounds where they live. However, while several studies have demonstrated phenotype–environment associations, few have directly shown that this confers an improvement in camouflage, particularly with respect to predator vision. Here, we show that an intertidal crustacean, the sand flea (Hippa testudinaria), has coloration tuned to the different substrates on which it occurs when viewed by potential avian predators. Individual sand fleas from a small, oceanic island (Ascension) matched the colour and luminance of their own beaches more closely than neighbouring beaches to a model of avian vision. Based on past work, this phenotype–environment matching is likely to be driven through ontogenetic changes rather than genetic adaptation. Our work provides some of the first direct evidence that animal coloration is tuned to provide camouflage to prospective predators against a range of visual backgrounds, in a population of animals occurring over a small geographical range.
Building a ninefold symmetrical barrel: structural dissections of centriole assembly
Authors: Dong Gang
Published: August 2015

Centrioles are short microtubule-based organelles with a conserved ninefold symmetry. They are essential for both centrosome formation and cilium biogenesis in most eukaryotes. A core set of five centriolar proteins has been identified and their sequential recruitment to procentrioles has been established. However, structures at atomic resolution for most of the centriolar components were scarce, and the underlying molecular mechanisms for centriole assembly had been a mystery—until recently. In this review, I briefly summarize recent advancements in high-resolution structural characterization of the core centriolar components and discuss perspectives in the field.
Optimal reconstruction of inviscid vortices
Authors: Danaila Ionut , Protas Bartosz
Published: August 2015

We address the question of constructing simple inviscid vortex models that optimally approximate realistic flows as solutions of an inverse problem. Assuming the model to be incompressible, inviscid and stationary in the frame of reference moving with the vortex, the ‘structure’ of the vortex is uniquely characterized by the functional relation between the streamfunction and vorticity. It is demonstrated how the inverse problem of reconstructing this functional relation from data can be framed as an optimization problem which can be efficiently solved using variational techniques. In contrast to earlier studies, the vorticity function defining the streamfunction–vorticity relation is reconstructed in the continuous setting subject to a minimum number of assumptions. To focus attention, we consider flows in three-dimensional axisymmetric geometry with vortex rings. To validate our approach, a test case involving Hill's vortex is presented in which a very good reconstruction is obtained. In the second example, we construct an optimal inviscid vortex model for a realistic flow in which a more accurate vorticity function is obtained than produced through an empirical fit. When compared with available theoretical vortex-ring models, our approach has the advantage of offering a good representation of both the vortex structure and its integral characteristics.
Oxygen changes drive non-uniform scaling inDrosophila melanogasterembryogenesis
Authors: Kuntz Steven G. , Eisen Michael B.
Published: August 2015

InDrosophilaembryogenesis, increasing either oxygen concentration or temperature accelerates development. Having previously investigated temperature’s impact on embryogenesis, we characterized developmental response to oxygen levels using time-lapse imaging. Changing oxygen concentrations greatly impact survival, with developmental rate changes that are dwarfed by those induced by temperature. While extreme temperatures increase early embryo mortality, mild hypoxia increases arrest and death during mid-embryogenesis and mild hyperoxia increases survival over normoxia. Though not independent, the reactions to temperature and oxygen are fundamentally different, with developmental time being inversely proportional to oxygen concentration but logarithmically related to temperature. Most notably, while development scales uniformly with temperature, oxygen changes drive developmental heterochrony. Morphological processes change with oxygen concentration at different rates. Gut formation is more severely slowed by decreases in oxygen, while head involution and syncytial development are less impacted than the rest of development. These data reveal that uniform scaling, seen with changes in temperature, is not the default result of adjusting developmental rate.
Fuzzy-FishNet: A highly precise distribution-free network approach for feature selection in clinical proteomics
Authors: Bin Goh Wilson Wen
Published: August 2015

Network-based analysis methods can help resolve coverage and inconsistency issues in proteomics data. Previously, it was demonstrated that a suite of rank-based network approaches (RBNAs) provides unparalleled consistency and reliable feature selection. However, reliance on the t-statistic/t-distribution and hypersensitivity (coupled to a relatively flat p-value distribution) makes feature prioritization for validation difficult. To address these concerns, a refinement based on the fuzzified Fisher exact test, Fuzzy-FishNet was developed. Fuzzy-FishNet is highly precise (providing probability values that allows exact ranking of features). Furthermore, feature ranks are stable, even in small sample size scenario. Comparison of features selected by genomics and proteomics data respectively revealed that in spite of relative feature stability, cross-platform overlaps are extremely limited, suggesting that networks may not be the answer towards bridging the proteomics-genomics divide.
Clinical metagenomic identification ofBalamuthia mandrillarisencephalitis and assembly of the draft genome: the critical need for reference strain sequencing
Authors: Greninger Alexander L. , Messacar Kevin , Dunnebacke Thelma , Naccache Samia N. , Federman Scot , Bouquet Jerome , Mirsky David , Nomura Yosuke , Yagi Shigeo , Glaser Carol , Vollmer Michael , Press Craig A. , Klenschmidt-DeMasters Bette K. , Dominguez Samuel R. , Chiu Charles Y.
Published: August 2015

Primary amoebic meningoencephalitis (PAM) is a rare, often lethal cause of encephalitis, for which early diagnosis and prompt initiation of combination antimicrobials may improve clinical outcomes. In this study, we present the first draft assembly of theBalamuthia mandrillarisgenome recovered from a rare survivor of PAM, in total comprising 49 Mb of sequence. Comparative analysis of the mitochondrial genome and high-copy number genes from 6 additionalBalamuthia mandrillarisstrains demonstrated remarkable sequence variation, with the closest homologs corresponding to other amoebae, hydroids, algae, slime molds, and peat moss,. We also describe the use of unbiased metagenomic next-generation sequencing (NGS) and SURPI bioinformatics analysis to diagnose an ultimately fatal case ofBalamuthia mandrillarisencephalitis in a 15-year old girl. Real-time NGS testing of a hospital day 6 CSF sample detectedBalamuthiaon the basis of high-quality hits to 16S and 18S ribosomal RNA sequences present in the National Center for Biotechnology Information (NCBI) nt reference database. Retrospective analysis of a day 1 CSF sample revealed that more timely identification ofBalamuthiaby metagenomic NGS, potentially resulting in a better outcome, would have required availability of the complete genome sequence. These results underscore the diverse evolutionary origins underpinning this eukaryotic pathogen, and the critical importance of whole-genome reference sequences for microbial detection by NGS.
Effect of multifaceted interventions on reducing return visits within 72 h after non‐traumatic emergency department visits
Authors: Lee Soo Hoon , Kim Kyuseok , Kim Hooyoung , Jeong Jin Hee , Kang Changwoo , Rhee Joong Eui , Byeon Young Im , Im Yeon Sook , Park Chanjong , Kim Joonghee , Hwang Seung Sik
Published: August 2015

Objective

The objective of the present study is to develop new multifaceted interventions to reduce return visits (RVs) based on identified risk factors related to RVs in the ED and to compare the RV rate before and after the implementation of the intervention.

Methods

The present study was a controlled before and after study that was conducted in the ED of a 900‐bed tertiary hospital in an urban area. The primary outcome was the rate of unplanned RVs to the ED and hospital admission after RV. The risk and predictive factors of RVs were identified by a retrospective study of all unscheduled RVs to the ED within 72 h in 2011. We developed five new multifaceted interventions based on the results: (i) daily RV feedback; (ii) prescription set of drugs; (iii) creation of a discharge instruction sheet; (iv) early follow‐up appointments of outpatient department (OPD); and (v) enhancement of referral system. A prospective interventional study in which the interventions were implemented was then conducted over 10 months, from 1 June 2012 to 31 March 2013.

Results

The five new multifaceted interventions significantly reduced the mean early RV rate and RV admission rate after ED discharge by an average of approximately 25%, with a maximum of approximately 55% and 47%, respectively, compared with the pre‐intervention period (RV rate: P < 0.001, RV admission rate: P < 0.001).

Conclusions

Multifaceted interventions based on identified risk factors for early RV after ED discharge had a positive effect on reducing RVs and the admission rate after RVs for adult patients within 72 h of non‐traumatic ED visits.
Review article: Potential of medical scribes to allay the burden of documentation and enhance efficiency in Australian emergency departments
Authors: Cabilan Cara J , Eley Robert M
Published: August 2015

The increasing burden of documentation experienced by doctors threatens the efficiency in EDs and increases the likelihood of documentation errors. Medical scribes afford the opportunity to allay this burden by removing a large component of the doctors' documentation task. Scribes have been embedded successfully in US EDs, and the effects have been mostly advantageous. The present paper provides a brief overview of the function of scribes and their potential contribution to Australian EDs.
Growth hormone modulates hypothalamic inflammation in long‐lived pituitary dwarf mice
Authors: Sadagurski Marianna , Landeryou Taylor , Cady Gillian , Kopchick John J. , List Edward O. , Berryman Darlene E. , Bartke Andrzej , Miller Richard A.
Published: August 2015

Mice in which the genes for growth hormone (GH) or GH receptor (GHR−/−) are disrupted from conception are dwarfs, possess low levels of IGF‐1 and insulin, have low rates of cancer and diabetes, and are extremely long‐lived. Median longevity is also increased in mice with deletion of hypothalamic GH‐releasing hormone (GHRH), which leads to isolated GH deficiency. The remarkable extension of longevity in hypopituitary Ames dwarf mice can be reversed by a 6‐week course of GH injections started at the age of 2 weeks. Here, we demonstrate that mutations that interfere with GH production or response, in the Snell dwarf, Ames dwarf, or GHR−/− mice lead to reduced formation of both orexigenic agouti‐related peptide (AgRP) and anorexigenic proopiomelanocortin (POMC) projections to the main hypothalamic projection areas: the arcuate nucleus (ARH), paraventricular nucleus (PVH), and dorsomedial nucleus (DMH). These mutations also reduce hypothalamic inflammation in 18‐month‐old mice. GH injections, between 2 and 8 weeks of age, reversed both effects in Ames dwarf mice. Disruption of GHR specifically in liver (LiGHRKO), a mutation that reduces circulating IGF‐1 but does not lead to lifespan extension, had no effect on hypothalamic projections or inflammation, suggesting an effect of GH, rather than peripheral IGF‐1, on hypothalamic development. Hypothalamic leptin signaling, as monitored by induction of pStat3, is not impaired by GHR deficiency. Together, these results suggest that early‐life disruption of GH signaling produces long‐term hypothalamic changes that may contribute to the longevity of GH‐deficient and GH‐resistant mice.
An insight into current concepts and techniques in resin bonding to high strength ceramics
Authors: Luthra R , Kaur P
Published: August 2015

Background

Reliable bonding between high strength ceramics and resin composite cement is difficult to achieve because of their chemical inertness and lack of silica content. The aim of this review was to assess the current literature describing methods for resin bonding to ceramics with high flexural strength such as glass‐infiltrated alumina and zirconia, densely sintered alumina and yttria‐partially stabilized tetragonal zirconia polycrystalline ceramic (Y‐TZP) with respect to bond strength and bond durability.

Methods

Suitable peer reviewed publications in the English language were identified through searches performed in PubMed, Google Search and handsearches. The keywords or phrases used were ‘resin‐ceramic bond’, ‘silane coupling agents’, ‘air particle abrasion’, ‘zirconia ceramic’ and ‘resin composite cements’. Studies from January 1989 to June 2015 were included.

Results

The literature demonstrated that there are multiple techniques available for surface treatments but bond strength testing under different investigations have produced conflicting results.

Conclusions

Within the scope of this review, there is no evidence to support a universal technique of ceramic surface treatment for adhesive cementation. A combination of chemical and mechanical treatments might be the recommended solution. The hydrolytic stability of the resin ceramic bond should be enhanced.
Benign melanocytic lymph node deposits in the setting of giant congenital melanocytic nevi: the large congenital nodal nevus
Authors: Bowen Anneli R. , Duffy Keith L. , Clayton Frederic C. , Andtbacka Robert H.I. , Florell Scott R.
Published: August 2015

Background

Benign melanocytic rests are a frequent finding in superficial lymph nodes removed during sentinel lymph node biopsies for melanoma. Whereas the histopathology of these deposits is well understood, very little is known regarding melanocytic lymph node deposits in the setting of giant congenital melanocytic nevi.

Methods

We analyzed lymph nodes removed from the drainage basin of giant congenital melanocytic nevi in three patients who had developed melanoma within their giant congenital nevi.

Results

Two of three patients showed widespread, capsular and parenchymal melanocytic deposits in multiple nodes (9 of 11 nodes in one patient and 6 of 8 in the other). Melanocytes were small, non‐mitotically active and resembled those in the associated giant congenital melanocytic nevus. Melanocytes were arranged singly and in small nests ∼0.05 mm in diameter, with some larger sheets up to 1 mm. Nodal melanocytes stained for Melan A and S100 on immunohistochemical evaluation, but showed negative or minimal HMB‐45 reactivity.

Conclusions

Evaluation of lymph nodes in the setting of giant congenital melanocytic nevi is complicated by the presence of often numerous, parenchymal melanocytic nevic deposits. Bland cytology and minimal or absent HMB‐45 staining may be helpful in differentiating these nodal melanocytic nevi from metastatic melanoma. We term this phenomena large congenital nodal nevus.
A histopathological study of melanocytic and pigmented skin lesions in patients with albinism
Authors: van der Westhuizen Gerhard , Beukes Catherine A. , Green Brent , Sinclair Werner , Goedhals Jacqueline
Published: August 2015

Background

Oculocutaneous albinism (OCA) is a group of genetic disorders characterized by diminished pigmentation of the skin, hair and eyes. Individuals with OCA are at increased risk to develop sun‐induced skin malignancies. The incidence of malignant melanoma in OCA individuals is, however, very low. The aim of this study was to document pigmented and melanocytic skin lesions occurring in patients with OCA.

Methods

A prospective study was performed. Sixteen patients with OCA presenting at the Oncology and Dermatology Departments at Universitas Academic Hospital Annex in Bloemfontein, South Africa, were included. Selected clinically pigmented and/or melanocytic lesions were biopsied and studied by light microscopy.

Results

Twenty‐four punch biopsies were taken. Ten dendritic freckles and 10 melanocytic nevi were confirmed histologically. The nevi, which occurred in eight patients, were found on sun‐protected skin. All the freckles occurred on sun‐exposed skin. Twelve patients had current or previous skin malignancies. No melanomas were present in the study population. Other skin lesions ranged from solar keratoses to squamous cell carcinomas.

Conclusion

The majority of pigmented lesions were dendritic freckles that occurred on sun‐exposed skin. None of the patients had a current or previous diagnosis of malignant melanoma.
Prior knowledge of the clinical picture does not introduce bias in the histopathologic diagnosis of melanocytic skin lesions
Authors: Ferrara Gerardo , Annessi Giorgio , Argenyi Zsolt , Argenziano Giuseppe , Beltraminelli Helmut , Cerio Rino , Cerroni Lorenzo , Cota Carlo , Simonetti Stefano , Stefanato Catherine M. , Zalaudek Iris , Kittler Harald , Soyer H. Peter
Published: August 2015

A common debate among dermatopathologists is that prior knowledge of the clinical picture of melanocytic skin neoplasms may introduce a potential bias in the histopathologic examination. Histologic slides from 99 melanocytic skin neoplasms were circulated among 10 clinical dermatologists, all of them formally trained and board‐certified dermatopathologists: 5 dermatopathologists had clinical images available after a ‘blind’ examination (Group 1); the other 5 had clinical images available before microscopic examination (Group 2). Data from the two groups were compared regarding ‘consensus’ (a diagnosis in agreement by ≥4 dermatopathologists/group), chance‐corrected interobserver agreement (Fleiss' k) and level of diagnostic confidence (LDC: a 1–5 arbitrary scale indicating ‘increasing reliability’ of any given diagnosis). Compared with Group 1 dermatopathologists, Group 2 achieved a lower number of consensus (84 vs. 90) but a higher k value (0.74 vs. 0.69) and a greater mean LDC value (4.57 vs. 4.32). The same consensus was achieved by the two groups in 81/99 cases. Spitzoid neoplasms were most frequently controversial for both groups. The histopathologic interpretation of melanocytic neoplasms seems to be not biased by the knowledge of the clinical picture before histopathologic examination.
Low‐grade cylindromatous adnexal carcinoma with unusual histopathological features: report of a case with comparative immunohistochemical study and meta‐analysis of the literature
Authors: Hayashi Toshitetsu , Haba Reiji , Katsuki Naomi , Kushida Yoshio , Kadota Kyuichi , Bando Kenji , Moriue Junko , Yokoi Ikumi , Izumi Miki , Kubota Yasuo
Published: August 2015

We present an extremely rare case of low‐grade cylindromatous adnexal carcinoma (CAC) on the right chest wall of a 77‐year‐old man. Histopathologically, the neoplasm was initially diagnosed as a cylindroma that developed over the course of 13 years. A diagnosis of low‐grade CAC was rendered after the documentation of a local recurrence and histopathology of the recurrent tumor. To further assess the evolution of low‐grade CAC over time, we compared the morphology, mitotic account, proliferative markers and adhesion molecule immunoreactivity among paired primary and recurrent tumors. Unlike those earlier reported, our case showed the maintenance of tumor morphology after a recurrence without areas of obvious malignant transformation or metaplastic change. We showed here for the first time the expression of adhesion molecules of CAC/spiradenoma and a comparison of proliferation indices between a primary tumor and its local recurrence. This peculiar tumor differs from previously reported cases and harbors a malignant potential although the histopathological features of malignancy are subtle. Our meta‐analysis of the literature provided background information regarding this rare entity. Alterations of E‐cadherin and GCDFP‐15 expression may provide additional helpful clues in differential diagnosis and determining the clinical behavior of this unusual neoplasm. Further studies are warranted to confirm the potential discriminative role of these markers.