bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple ion species plasmas with thermal ions in an oblique magnetic field
Authors: Hatami M. M.
Published: August 2013

Using a three-fluid model, the combined effects of an oblique magnetic field and finite temperature of positive ion species on the characteristics of the sheath region of multi-component plasmas are investigated numerically. It is assumed that the ion species are singly charged and have different masses. In the presence of an external magnetic field, it is shown that the density distribution of positive ion species (especially the lighter ion species) begins to fluctuate and does not decrease monotonically towards the wall. Also, it is shown that by increasing the magnetic field, the amplitude of fluctuation increases and its position moves towards the sheath edge. Moreover, it is illustrated that the presence of the magnetic field affects the sheath width and by increasing the magnetic field, the sheath width decreases. In addition, the results show that in the presence of the magnetic field, the increase of temperature of positive ion species has an infinitesimal effect on the sheath width and density distribution of positive ion species.
On the possibility of spontaneous generation of turbulent Alfvén waves in solar plasma by heavy ions
Authors: Wu C. S. , Zhao G. Q. , Chen L. , Wu D. J.
Published: August 2013

In this paper, we discuss spontaneous generation of Alfvén waves. The discussion is motivated by the study of the solar transition region. We show that the heavy ions in this region can play critical roles. A quasilinear theory is derived. On the basis of this theory, we can discuss the saturation level of the wave spectral energy associated with each species of ions. Several essential issues relevant to the transition region are also discussed.
Magnetic anisotropy modified by electric field in V/Fe/MgO(001)/Fe epitaxial magnetic tunnel junction
Authors: Rajanikanth A. , Hauet T. , Montaigne F. , Mangin S. , Andrieu S.
Published: August 2013

Single-crystalline V/Fe(0.7 nm)/MgO(1.2nm)/Fe(20 nm) magnetic tunnel junctions are studied to quantify the influence of an electric field on the Fe/MgO interface magnetic anisotropy. The thinnest Fe soft layer has a perpendicular magnetic anisotropy (PMA), whereas the thickest Fe layer acts as sensor for magnetic anisotropy changes. When electrons are added at the PMA Fe/MgO interface (negative voltage), no anisotropy changes are observed. For positive voltage, the anisotropy constant decreases with increasing bias voltage. A huge 1150 fJ V−1 m−1 anisotropy variation with field is observed and the magnetization is found to turn from out-of-plane to in-plane of the sample with the applied voltage.
Enhancement of programming speed on gate-all-around poly-silicon nanowire nonvolatile memory using self-aligned NiSi Schottky barrier source/drain
Authors: Ho Ching-Yuan , Chang Yaw-Jen , Chiou Y. L.
Published: August 2013

The programming characteristics of gate-all-around silicon-oxide-nitride-oxide silicon (SONOS) nonvolatile memories are presented using NiSi/poly-Si nanowires (SiNW) Schottky barrier (SB) heterojunctions. The non-uniform thermal stress distribution on SiNW channels due to joule heating affected the carrier transport behavior. Under a high drain voltage, impact ionization was found as a large lateral field enhances carrier velocity. As gate voltage (Vg) increased, the difference in the drain current within a range of various temperature conditions can be mitigated because a high gate field lowers the SB height of a NiSi source/SiNW/NiSi drain junction to ensure efficient hot-carrier generation. By applying the Fowler-Nordheim programming voltage to the SONOS nanowire memory, the SB height (Φn = 0.34 eV) could be reduced by image force; thus, hot electrons could be injected from SB source/drain electrodes into the SiN storage node. To compare both SiNW and Si nanocrystal SONOS devices, the SB SiNW SONOS device was characterized experimentally to propose a wider threshold-voltage window, exhibiting efficient programming characteristics.
Laser-driven 1 GeV carbon ions from preheated diamond targets in the break-out afterburner regime
Authors: Jung D. , Yin L. , Gautier D. C. , Wu H.-C. , Letzring S. , Dromey B. , Shah R. , Palaniyappan S. , Shimada T. , Johnson R. P. , Schreiber J. , Habs D. , Fernández J. C. , Hegelich B. M. , Albright B. J.
Published: August 2013

Experimental data are presented for laser-driven carbon C6+ ion-acceleration, verifying 2D-PIC studies for multi-species targets in the Break-Out Afterburner regime. With Trident's ultra-high contrast at relativistic intensities of 5 × 1020 W/cm2 and nm-scale diamond targets, acceleration of carbon ions has been optimized by using target laser-preheating for removal of surface proton contaminants. Using a high-resolution wide angle spectrometer, carbon C6+ ion energies exceeding 1 GeV or 83 MeV/amu have been measured, which is a 40% increase in maximum ion energy over uncleaned targets. These results are consistent with kinetic plasma modeling and analytic theory.
Macroscopic self ordering of solution processible poly(3,3″′-dialkylquaterthiophene) by floating film transfer method
Authors: Pandey Rajiv K. , Takashima Wataru , Nagamatsu Shuichi , Dauendorffer Arnaud , Kaneto K. , Prakash Rajiv
Published: August 2013

Ordering and alignment of π-conjugated polymer chains are highly desirable for high performance and long life organic electronic devices. We report here self assembly of ordered and aligned solution processible Poly(3,3″′-dialkylquaterthiophene) (PQT-12) polymer at macroscopic level using Floating Film Transfer Method (FTM). PQT-12 polymer film is formed over solution of ethylene glycol and glycerol at different temperatures viz. 22, 26, 33, and 38 °C. PQT-12 films formed by FTM technique are further characterized for optical and morphological properties. UV-vis absorption (for polarize and unpolarize light) and surface topography/phase imaging are carried out by using UV-vis spectrometer and atomic force microscope (AFM), respectively. UV-vis spectra show the polymer chains alignment perpendicular to the film propagation direction and it is well supported by AFM images. The effect of temperature on ordering and alignment of PQT-12 shows 33 °C as an optimum temperature for alignment of polymer chains (a little compromise in ordering). The heating of polymer films at 110 °C for 2 h in ambient causes significant changes in UV-vis absorbance spectra, optical anisotropy, and AFM topography/phase imaging. Our studies provide better understanding of ordering and alignment of PQT-12 chains and also disordering on heating. This work further provides a facile and user-friendly technique for the long range ordered self assembly of PQT-12, which shows enormous potential for various electronic applications.
Dissociation and excitation coefficients of nitrogen molecules and nitrogen monoxide generation
Authors: Uhm Han S. , Na Young H. , Choi Eun H. , Cho Guangsup
Published: August 2013

The excitation coefficient αN2 is calculated for the excited metastable level of N2(A3∑u+) in nitrogen molecules. In addition, the dissociation coefficient of nitrogen molecules is investigated by making use of the Boltzmann distribution of the electrons in atmospheric plasmas. The excitation and electron-impact dissociation coefficients of nitrogen molecules are analytically expressed in terms of the electron temperature Te for evaluations of the reactive oxygen and nitrogen species in atmospheric plasmas. As an application example of these coefficients, the nitrogen monoxide generation through a microwave torch is carried out for a development of medical tool. The nitrogen monoxide concentration from a microwave plasma-torch can be easily controlled by the nitrogen flow rate, mole fraction of the oxygen gas, and the microwave power. A simple analytic expression of the nitrogen monoxide concentration is obtained in terms of the oxygen molecular density and gas flow rate. The experimental data agree remarkably well with the theoretical results from the analytical expression. A microwave nitrogen-torch can easily provide an appropriate nitrogen monoxide concentration for the wound healings.
Finite Mach number spherical shock wave, application to shock ignition
Authors: Vallet A. , Ribeyre X. , Tikhonchuk V.
Published: August 2013

A converging and diverging spherical shock wave with a finite initial Mach number Ms0 is described by using a perturbative approach over a small parameter Ms−2. The zeroth order solution is the Guderley's self-similar solution. The first order correction to this solution accounts for the effects of the shock strength. Whereas it was constant in the Guderley's asymptotic solution, the amplification factor of the finite amplitude shock Λ(t)∝dUs/dRs now varies in time. The coefficients present in its series form are iteratively calculated so that the solution does not undergo any singular behavior apart from the position of the shock. The analytical form of the corrected solution in the vicinity of singular points provides a better physical understanding of the finite shock Mach number effects. The correction affects mainly the flow density and the pressure after the shock rebound. In application to the shock ignition scheme, it is shown that the ignition criterion is modified by more than 20% if the fuel pressure prior to the final shock is taken into account. A good agreement is obtained with hydrodynamic simulations using a Lagrangian code.
On the classification of dielectric barrier discharge plasma actuators: A comprehensive performance evaluation study
Authors: Kriegseis J. , Duchmann A. , Tropea C. , Grundmann S.
Published: August 2013

The increasing popularity and maturity of plasma actuators for many flow control applications requires a common standard for plasma actuator performance evaluation. In the present work, a comprehensive comparative study of existing and new evaluation measures is presented, based on results from identical plasma-actuator configurations. A power-flow diagram is introduced that covers the entire range of power stages from the energy source to the flow-control success. All individual power stages are explained, existing controversial definitions are clarified, and an evaluation guideline is applied to previously obtained data. Finally, the defined systematic analysis is applied to the results of a recently conducted plasma-actuator in-flight experiment.
Plasmonic enhancement of spontaneous emission from wide-linewidth emitters with nanostrip metallic waveguide
Authors: Zhang Chao , Feng Xue , Cui Kaiyu , Huang Yidong
Published: August 2013

Purcell factor of a nanostrip plasmon waveguide is evaluated via a full integration form of Fermi's golden rule and power dissipation spectrum. Purcell factor is dramatically increased with narrower strip width, corresponding to the tight confinement in the ultrasmall gap region. Furthermore, inclusion of energy distribution among useful and lossy modes would reduce the Purcell factor severely, yet the enhancement range could be broadened and the tolerance of emission linewidth strengthened. Although the dissipation issue remains serious near the resonant frequency, it is shown that wide-linewidth emitters in the off-resonance region could also be effectively enhanced with nanostrip waveguide, suggesting a promising path to practical integrated emitters.
Effect of carbon doping on electronic transitions in Mn5Ge3
Authors: Stojilovic N. , Dordevic S. V. , Hu Rongwei , Petrovic C.
Published: August 2013

Mn5Ge3 is a ferromagnetic compound with high Curie temperature (Tc = 293 K), high spin polarization, and a good lattice match to germanium. Doping Mn5Ge3 with carbon increases Tc above room temperature and makes these compounds promising candidates for spin injectors for potential spintronics applications. The resistivity and magnetic susceptibility measurements show anisotropic behavior of these compounds. Optical spectroscopy is employed to measure near-normal reflectance of Mn5Ge3C0.89 in the frequency range from far-infrared to ultraviolet at three different temperatures (10, 200, and 300 K), and results are compared with those on pure Mn5Ge3. Both Mn5Ge3 and Mn5Ge3C0.89 have weak temperature dependence of the optical properties in the 10–300 K range, and both have similar electrodynamics responses with similar temperature trends. However, important differences in the region of interband transitions, indicating the electronic nature of the increased ferromagnetic stability of carbon doped compound, are observed.
Mixed mode and sequential oscillations in the cerium-bromate-4-aminophenol photoreaction
Authors: Bell Jeffrey G. , Wang Jichang
Published: August 2013

Cerium was introduced to the bromate-aminophenol photochemical oscillator to implement coupled autocatalytic feedbacks. Mixed mode and sequential oscillations emerged in the studied system, making it one of the few chemical oscillators known to support consecutive bifurcations in a batch system. The complex reaction behavior showed a strong dependence on the intensity of illumination supplied to the system. Removal of illumination during an oscillatory window affected both the frequency and amplitude of the oscillation but did not fully extinguish them, indicating that the cerium-bromate-4-aminophenol oscillator was photosensitive rather than photo-controlled. A moderate light intensity allowed for a slow evolution of the system, which proved to be critical for the emergence of transient complex oscillations. Variation of individual reaction parameters was carried out, which indicated that the development of complex oscillations occur in a narrow region and a phase diagram in the 4-aminophenol and sulfuric acid plane demonstrated this. Simulations provide strong support that transient complex oscillations observed experimentally arise from the coupling of two autocatalytic cycles.
Ion irradiation synthesis of Ag–Au bimetallic nanospheroids in SiO2 glass substrate with tunable surface plasmon resonance frequency
Authors: Meng Xuan , Shibayama Tamaki , Yu Ruixuan , Takayanagi Shinya , Watanabe Seiichi
Published: August 2013

Ag–Au bimetallic nanospheroids with tunable localized surface plasmon resonance (LSPR) were synthesized by 100 keV Ar–ion irradiation of 30 nm Ag–Au bimetallic films deposited on SiO2 glass substrates. A shift of the LSPR peaks toward shorter wavelengths was observed up to an irradiation fluence of 1.0 × 1017 cm−2, and then shifted toward the longer wavelength because of the increase of fragment volume under ion irradiation. Further control of LSPR frequency over a wider range was realized by modifying the chemical components. The resulting LSPR frequencies lie between that of the pure components, and an approximate linear shift of the LSPR toward the longer wavelength with the Au concentration was achieved, which is in good agreement with the theoretical calculations based on Gans theory. In addition, the surface morphology and compositions were examined with a scanning electron microscope equipped with an energy dispersive spectrometer, and microstructural characterizations were performed using a transmission electron microscope. The formation of isolated photosensitive Ag–Au nanospheroids with a FCC structure partially embedded in the SiO2 substrate was confirmed, which has a potential application in solid-state devices.
Determination of gain in AlGaN cladding free nitride laser diodes
Authors: Muziol G. , Turski H. , Siekacz M. , Sawicka M. , Wolny P. , Perlin P. , Skierbiszewski C.
Published: August 2013

The optical gain spectra of InGaN-based multiple-quantum-well (MQW) laser diodes (LDs) grown by plasma-assisted molecular beam epitaxy are compared for different emission wavelengths. Two AlGaN cladding free LDs with similar epitaxial structures but with different In compositions in MQW were grown to study the dependence of material gain on lasing wavelength. As the emission wavelength increased from 432 to 458 nm, the differential modal gain decreased from 5.7 to 4.7 cm/kA, and the optical losses increased from 40 to 46 cm−1 resulting in an increase in threshold current density. This dependence is attributed to lower optical mode confinement of LD emitting at longer wavelength. We found a strong decrease of confinement factor with increasing wavelength.
Strain analysis of highly scalable single InAs/InP quantum dots in a stress-sensitive environment
Authors: Mnaymneh K. , Dalacu D. , Poole P. J. , Williams R. L.
Published: August 2013

We perform an experimental and computational study of the effects of external stress and intermixing on single site-selected InAs/InP quantum dots in a highly scalable stress-sensitive environment. While such effects are well known for their ability to tune emission spectra, little is known on how they influence emission shell spacing, electron-hole effective mass renormalization, and the physical size of the embedded quantum dot, which are all important parameters affecting the intended functionality. We show excellent agreement between experiment and finite-element solutions of the coupled Navier and Schrödinger equations, including recent atomistic pseudopotential calculations in the literature. These results indicate that using single self-assembled quantum dots in highly scalable, stress-sensitive settings as active elements in future bottom-up nanosystems offers greater versatility to not only quantum information systems where they serve as scalable single-photon sources but also to ultra-sensing capabilities in future nano-electro-mechanical architectures.
Field tested milliliter-scale blood filtration device for point-of-care applications
Authors: Gong Max M. , MacDonald Brendan D. , Vu Nguyen Trung , Van Nguyen Kinh , Sinton David
Published: August 2013

In this paper, we present a low cost and equipment-free blood filtration device capable of producing plasma from blood samples with mL-scale capacity and demonstrate its clinical application for hepatitis B diagnosis. We report the results of in-field testing of the device with 0.8–1 ml of undiluted, anticoagulated human whole blood samples from patients at the National Hospital for Tropical Diseases in Hanoi, Vietnam. Blood cell counts demonstrate that the device is capable of filtering out 99.9% of red and 96.9% of white blood cells, and the plasma collected from the device contains lower red blood cell counts than plasma obtained from a centrifuge. Biochemistry and immunology testing establish the suitability of the device as a sample preparation unit for testing alanine transaminase (ALT), aspartate transaminase (AST), urea, hepatitis B “e” antigen (HBeAg), hepatitis B “e” antibody (HBe Ab), and hepatitis B surface antibody (HBs Ab). The device provides a simple and practical front-end sample processing method for point-of-care microfluidic diagnostics, enabling sufficient volumes for multiplexed downstream tests.
64 μW pulsed terahertz emission from growth optimized InGaAs/InAlAs heterostructures with separated photoconductive and trapping regions
Authors: Dietz Roman J. B. , Globisch Björn , Gerhard Marina , Velauthapillai Ajanthkrishna , Stanze Dennis , Roehle Helmut , Koch Martin , Göbel Thorsten , Schell Martin
Published: August 2013

We present results on optimized growth temperatures and layer structure design of high mobility photoconductive Terahertz (THz) emitters based on molecular beam epitaxy grown In0.53Ga0.47As/In0.52Al0.48As multilayer heterostructures (MLHS). The photoconductive antennas made of these MLHS are evaluated as THz emitters in a THz time domain spectrometer and with a Golay cell. We measured a THz bandwidth in excess of 4 THz and average THz powers of up to 64 μW corresponding to an optical power-to-THz power conversion efficiency of up to 2 × 10−3.
Magnonic crystals composed of Ni80Fe20 film on top of Ni80Fe20 two-dimensional dot array
Authors: Liu X. M. , Ding J. , Kakazei G. N. , Adeyeye A. O.
Published: August 2013

Modulated structures consisting of square arrays of 60 nm thick Ni80Fe20 circular dots underneath a continuous Ni80Fe20 film were fabricated using multi-level process based on deep ultraviolet lithography at 248 nm exposure wavelength. We observed a drastic change in both the static and dynamic properties of the modulated structures by varying the Ni80Fe20 film thickness t in the range from 5 to 60 nm. It was revealed via comparison between experimental results and micromagnetic simulations that the dots create perturbations of internal fields in the neighbor regions of the film which can be controlled by magnetic field and film thickness.
Optimizing the light absorption of graphene-based organic solar cells by tailoring the weak microcavity with dielectric/graphene/dielectric multilayer
Authors: Chen Yi , Long Yongbing , Liu Yangtian , Shen Liang , Zhang Yangdong , Deng Qiguang , Zheng Zhuoshen , Yu Wenjuan , Ruan Shenping
Published: August 2013

Investigation into the organic solar cells (OSCs) with graphene electrode demonstrates that the weak-microcavity (WMC) constructed between the transparent electrode and top metal electrode plays an important role in the absorption properties of the devices. If the WMC structure is not optimized, the absorption of the graphene-based devices cannot surpass that of OSC devices with indium tin oxide electrode. By employing dielectric/graphene/dielectric multilayer to optimize the WMC, the absorption can be improved by a maximum value of 21.1% within a broad wavelength range of 410–636 nm. Correspondingly, an improvement of 12.1% in total absorbed photons is achieved for the device.
Infrared photoconductivity of Er-doped Si nanoclusters embedded in a slot waveguide
Authors: Anopchenko A. , Prtljaga N. , Tengattini A. , Fedeli J.-M. , Pavesi L.
Published: August 2013

Infrared photoconductive and photovoltaic effects are observed in Er-doped Si nanoclusters incorporated in a silicon p-i-n slot-waveguide device. These effects are ascribed to deep gap states of Si nanoclusters. The room temperature open circuit voltage of the devices is 290 mV under transmission of guided light at 1.5 μm. A power dependence, with the exponent close to 0.5 and 1 for forward and reverse bias, respectively, has been observed for the photocurrent versus light intensity characteristic. The former is attributed to bimolecular recombination (empty deep gap states) and the latter to linear recombination with the states being populated with electrons.
Comparative study of deep defects in ZnO microwires, thin films and bulk single crystals
Authors: Schmidt F. , Müller S. , von Wenckstern H. , Dietrich C. P. , Heinhold R. , Kim H.-S. , Allen M. W. , Grundmann M.
Published: August 2013

Electrical properties of a ZnO microwire grown by carbo-thermal evaporation, a ZnO thin film grown by pulsed-laser deposition and a hydrothermally grown ZnO bulk crystal are compared. Deep defects were investigated by means of deep-level transient spectroscopy. The defect level E3 was observed in all samples investigated. Additionally, a defect labelled T2 that preferentially forms under Zn-rich condition was detected in the microwire, the thin film and the bulk sample. Our results indicate that VZn is likely involved in this defect.
Optimizing TaOx memristor performance and consistency within the reactive sputtering “forbidden region”
Authors: Lohn Andrew J. , Stevens James E. , Mickel Patrick R. , Marinella Matthew J.
Published: August 2013

Standard deposition processes for depositing ReRAM oxides utilize mass flow of reactive gas to control stoichiometry and have difficulty depositing a precisely defined sub-stoichiometry within a “forbidden region” where film properties are discontinuous with mass flow. We show that by maintaining partial pressure within this discontinuous “forbidden region,” instead of by maintaining mass flow, we can optimize tantalum oxide device properties and reduce or eliminate the electroforming step. We also show that defining the partial pressure set point as a fraction of the “forbidden region” instead of as an absolute value can be used to improve wafer-to-wafer consistency with minimal recalibration efforts.
Theoretical Studies for Ozonide Formation During the Ozonolysis of Bicyclic Endoperoxides
Authors: Cain Nicole M. , Hixson Josh L. , Taylor Dennis K.
Published: August 2013

Theoretical investigations on the treatment of bicyclic endoperoxides (1,2-dioxines) with ozone at the HF/6–31G*, MP2/6–31G* or 6–311G*, and DFT(B3LYP)/6–31G* levels of theory indicate that the estimated activation energies for formation of the possible endo-endo, endo-exo, exo-endo, or exo-exo transition states along with the formation of the primary ozonides and product ozonides are very sensitive to effects of electron correlation and basis set. This study suggests that MP2/6–311G* is the best level of theory for evaluating such systems. At the MP2/6–311G* level of theory it was found that the transition state for primary ozonide formation was lowest in energy when ozone approaches in an endo facial fashion with a further 3 kJ mol–1 stabilisation seen when the central oxygen within the primary ozonide protrudes outwards (exo) as opposed to inwards (endo). The product ozonides are predicted to be more stable than the combined starting materials by some 380–580 kJ mol–1 depending on the level of theory, clearly highlighting the substantive exothermic nature of this type of ozonolysis reaction.
Youth Labour Market Integration Across Europe
Authors: de Lange Marloes , Gesthuizen Maurice , Wolbers Maarten H.J.
Published: August 2013

Young people in Europe face great difficulties nowadays when entering the labour market. Unemployment and temporary employment are high among youth, although considerable differences exist between European countries. In this article, we study to what extent cyclical, structural, and institutional factors explain cross-national variation in youth labour market integration. In addition, we examine educational differences in the impact of these macro-characteristics. To answer these questions, we use data on young people from 29 countries who were interviewed in the European Social Survey of 2002, 2004, 2006, or 2008 and left day-time education in the period 1992–2008. Both unemployment and temporary employment are regarded as a lack of labour market integration, compared to the situation of permanent employment. The empirical results first of all show that high unemployment hinders young people to smoothly integrate into the labour market. In addition, economic globalisation positively affects youth labour market integration. We also demonstrate that young people experience less difficulties with labour market integration as the educational system is more vocationally specific. Intermediate and higher educated particularly profit from the positive effect of the vocational specificity of the educational system. Finally, as the employment protection legislation of incumbent workers is stricter, young people experience more difficulties with labour market integration, especially higher educated youth.
The state and identity: the relationship between religion and politics – Tunisia as an example
Authors: Jourchi Salaheddine
Published: August 2013

This paper presents the discourse, or more often the struggle, between secularists and Islamists in Tunisia relating religion and the state within the desired democratic system. The movement of 18 October is a landmark in the efforts for constructive work between different political constituents which emphasized that the relationship between religion and the state is not expected to have a ready-made formula; instead, it is the product of a social pact that interacts with politics, culture and economics. The paper looks into the basis or foundation for cooperation, the feasibility of the merger between religion and the state, the timing – before or after democracy takes hold – the focus on form and substance of democracy, its connection to laws, etc. Whereas it may be possible to separate religion from the state, it is not possible to separate it from politics as this requires a dissociation of some devout believers from their system of belief, thus denying their basic rights. There are no guarantees that within a democratic system some groups and parties basing themselves on religion will be against democracy. These groups should remain part of the political system, the solution being to honour a social pact that is based on respecting constitutional institutions, national identity, principles of the republican system and human rights.
Microtubule severing by the katanin complex is activated by PPFR-1–dependent MEI-1 dephosphorylation
Authors: Gomes José-Eduardo , Tavernier Nicolas , Richaudeau Bénédicte , Formstecher Etienne , Boulin Thomas , Mains Paul E. , Dumont Julien , Pintard Lionel
Published: August 2013

Katanin is an evolutionarily conserved microtubule (MT)-severing complex implicated in multiple aspects of MT dynamics. In Caenorhabditis elegans, the katanin homologue MEI-1 is required for meiosis, but must be inactivated before mitosis. Here we show that PPFR-1, a regulatory subunit of a trimeric protein phosphatase 4 complex, enhanced katanin MT-severing activity during C. elegans meiosis. Loss of ppfr-1, similarly to the inactivation of MT severing, caused a specific defect in meiosis II spindle disassembly. We show that a fraction of PPFR-1 was degraded after meiosis, contributing to katanin inactivation. PPFR-1 interacted with MEL-26, the substrate recognition subunit of the CUL-3 RING E3 ligase (CRL3MEL-26), which also targeted MEI-1 for post-meiotic degradation. Reversible protein phosphorylation of MEI-1 may ensure temporal activation of the katanin complex during meiosis, whereas CRL3MEL-26-mediated degradation of both MEI-1 and its activator PPFR-1 ensure efficient katanin inactivation in the transition to mitosis.
Cryo-electron tomography: The challenge of doing structural biology in situ
Authors: Lučić Vladan , Rigort Alexander , Baumeister Wolfgang
Published: August 2013

Electron microscopy played a key role in establishing cell biology as a discipline, by producing fundamental insights into cellular organization and ultrastructure. Many seminal discoveries were made possible by the development of new sample preparation methods and imaging modalities. Recent technical advances include sample vitrification that faithfully preserves molecular structures, three-dimensional imaging by electron tomography, and improved image-processing methods. These new techniques have enabled the extraction of high fidelity structural information and are beginning to reveal the macromolecular organization of unperturbed cellular environments.
Bob Goldstein: Cell biology by way of development
Authors: Sedwick Caitlin
Published: August 2013

Goldstein is studying the cell biology of how organisms develop.
Peak flow as a predictor of cause-specific mortality in China: results from a 15-year prospective study of ∼170 000 men
Authors: Smith Margaret , Zhou Maigeng , Wang Lijun , Peto Richard , Yang Gonghuan , Chen Zhengming
Published: August 2013

Background Forced expiratory volume in one second (FEV1) is inversely associated with mortality in Western populations, but few studies have assessed the associations of peak expiratory flow (PEF) with subsequent cause-specific mortality, or have used populations in developing countries, including China, for such assessments.

Methods A prospective cohort study followed ∼170 000 Chinese men ranging in age from 40–69 years at baseline (1990–1991) for 15 years. In the study, height-adjusted PEF (h-PEF), which was uncorrelated with height, was calculated by dividing PEF by height. Hazard ratios (HR) for cause-specific mortality and h-PEF, adjusted for age, area of residence, smoking, and education, were calculated through Cox regression analyses.

Results Of the original study population, 7068 men died from respiratory causes (non-neoplastic) and 22 490 died from other causes (including 1591 from lung cancer, 5469 from other cancers, and 10 460 from cardiovascular disease) before reaching the age of 85 years. Respiratory mortality was strongly and inversely associated with h-PEF. For h-PEF ≥ 250 L/min, the association was log-linear, with a hazard ratio (HR) of 1.29 (95% CI: 1.25–1.34) per 100 L/min reduction in h-PEF. The association was stronger but not log-linear for lower values of h-PEF. Mortality from combined other causes was also inversely associated with h-PEF, and the association was log-linear for all values of h-PEF, declining with follow-up, with HRs per 100 L/min reduction in h-PEF of 1.13 (1.10–1.15), 1.08 (1.06–1.11), and 1.06 (1.03–1.08) in three consecutive 5-year follow-up periods. Specifically, lower values of h-PEF were associated with higher mortality from cardiovascular disease and lung cancer, but not from other cancers.

Conclusions A lower value of h-PEF was associated with increased mortality from respiratory and other causes, including lung cancer and cardiovascular disease, but its associations with the other causes of death declined across the follow-up period.
Chemical defensive symbioses in the marine environment
Authors: Lopanik Nicole B.
Published: August 2013

Marine organisms are a prolific source of natural products, many of which have become the target of pharmacological investigations. As well as being bioactive, these compounds can play an important role in the survival of the organisms and potentially affect community structure. Sessile invertebrates such as sponges, cnidarians, bryozoans and tunicates, in particular, are an especially rich source of ecologically relevant compounds. These organisms are typically soft‐bodied and unable to escape predators, and as such, they rely on chemical defence for their persistence. These invertebrates are also frequently hosts for microbial symbionts.

Marine microbes are a prolific source of bioactive natural products, many of which can be allelopathic and prevent the growth of pathogens. For sessile marine invertebrates, which often have both bioactive natural products and microbial symbionts, it is logical to hypothesize that microbial symbionts may produce the secondary metabolites.

While symbionts are often thought to be responsible for producing bioactive natural products that play a role in host defence, relatively few studies have experimentally demonstrated that symbiont‐produced compounds defend the hosts. One reason for this is the difficulty of manipulating the host–symbiont relationship, which is often obligate for one or both partners. Given the importance of natural products to marine invertebrates for defence, the prevalence of symbiosis in the marine environment and the diverse metabolic capabilities of micro‐organisms, symbiont‐mediated host chemical defence may be more prevalent than currently understood.

In this review, I document evidence supporting chemical defensive symbioses in marine organisms, discuss commonalities and differences among the diverse relationships, and provide future research directions. Epibiont‐produced defensive compounds would seem to result in the most efficient manner of protection, as the compounds are most accessible to the predators. By contrast, endosymbiont‐produced compounds may need to be transported to exposed tissues. Elucidating mechanisms to transport symbiont‐produced defensive compounds within the host will provide greater insight into the breadth and complexity of host–symbiont interactions. Another important unexplored issue is how the hosts are able to tolerate symbiont‐produced metabolites that are often eucaryotic cell effectors. A greater understanding of defensive symbiosis will result from detailed studies of the co‐evolution of predator, host and symbiont, and if or how predators can influence the production of defensive metabolites.
Genetic vs. non‐genetic responses of leaf morphology and growth to elevation in temperate tree species
Authors: Vitasse Yann , Lenz Armando , Kollas Chris , Randin Christophe F. , Hoch Günter , Körner Christian
Published: August 2013

At high elevation, temperate trees generally exhibit adaptive genetic differentiation in their morphological and physiological traits. On account of this directional selection, we hypothesized that tree populations growing near their upper cold elevational limits exhibit lower phenotypic plasticity of growth and leaf morphological traits in response to temperature changes than populations growing at lower elevations.

Seedlings of six common deciduous tree species originating from low and high elevations were transplanted into eight common gardens along two elevational gradients in the Swiss Alps. The aim of the experiment was to evaluate the genetic differentiation in growth and leaf morphology between populations from low and high elevations and to quantify the phenotypic plasticity of these traits to temperature changes.

In contrast to growth that decreased with increasing elevation, leaf mass per area (LMA) showed no significant change with elevation of common garden, except for a decrease inLaburnum alpinumfor both low‐ and high‐elevation provenances. Interestingly, leaf density was found to decrease with elevation of the gardens for all species. Genetic differentiation between low‐ and high‐elevation populations was found in both leaf morphology and growth: high‐elevation populations tended to have slower growth rate than low‐elevation populations, while no consistent trend was found forLMAacross species. Interestingly, forAcer pseudoplatanusandFraxinus excelsiorhigh‐elevation populations exhibited a lower phenotypic plasticity of growth in response to temperature compared to lower populations, whereas no interactions between the elevation of a provenance and the elevation of the garden was detected for the four other species.

Hence, during young life stages, the expected increase in tree growth in future warmer climates might be lower in populations living in the coldest part of the species distribution range in temperate species such asAcer pseudoplatanusandFraxinus excelsior, but similar in other tree species, disregarding other environmental changes.
Facilitating early activities of daily living retraining to prevent functional decline in older adults
Authors: Shearer Tania , Guthrie Sarah
Published: August 2013

Background/aim

Older people admitted to acute hospitals are at risk of functional decline. There is limited research into strategies that reduce such risks. The aim of this study was to investigate whether individualised activities of daily living retraining programmes improve functional outcomes, influence the choice of discharge destinations and reduce length of stay for older people in acute care.

Methods

A pilot non‐randomised controlled study (pre‐test/post‐test) with block allocation to control and intervention groups was undertaken in an acute geriatric unit at a large teaching hospital. The study was conducted over a six‐month period in two consecutive blocks. The intervention group received activities of daily living retraining three times per week for up to one hour per session. The control group received standard, mainly assessment‐based occupational therapy services. The Modified Barthel Index was used to measure functional status on admission and discharge.

Results

At discharge, there was no statistical difference in the change of total Modified Barthel Index score between control and intervention groups. Of the 10 items scored on the Modified Barthel Index, ambulation and chair/bed transfers approached significance (P = 0.0603 and P = 0.0547 respectively). No evidence was found for a difference in length of stay between intervention and control groups (mean length of stay 15.2 vs. 11.7 days respectively, P = 0.19). Raw data suggested that retraining programmes may reduce the level of care patients required on discharge.

Conclusions

Trends from this study indicate that functional retraining programmes could be effective in preventing functional decline. Further research is needed to reach more definite conclusions.
Home as a hybrid centre of medication practice
Authors: Dew Kevin , Chamberlain Kerry , Hodgetts Darrin , Norris Pauline , Radley Alan , Gabe Jonathan
Published: August 2013

This article presents research that explores how medications are understood and used by people in everyday life. An intensive process of data collection from 55 households was used in this research, which included photo‐elicitation and diary‐elicitation interviews. It is argued that households are at the very centre of complex networks of therapeutic advice and practice and can usefully be seen as hybrid centres of medication practice, where a plethora of available medications is assimilated and different forms of knowledge and expertise are made sense of. Dominant therapeutic frameworks are tactically manipulated in households in order for medication practices to align with the understandings, resources and practicalities of households. Understanding the home as a centre of medication practice decentralises the role of health advisors (whether mainstream or alternative) in wellness practices.
Prediction of Sweetness by Multilinear Regression Analysis and Support Vector Machine
Authors: Zhong Min , Chong Yang , Nie Xianglei , Yan Aixia , Yuan Qipeng
Published: August 2013

The sweetness of a compound is of large interest for the food additive industry. In this work, 2 quantitative models were built to predict the logSw (the logarithm of sweetness) of 320 unique compounds with a molecular weight from 132 to 1287 and a sweetness from 22 to 22500000. The whole dataset was randomly split into a training set including 214 compounds and a test set including 106 compounds, represented by 12 selected molecular descriptors. Then, logSw was predicted using a multilinear regression (MLR) analysis and a support vector machine (SVM). For the test set, the correlation coefficients of 0.87 and 0.88 were obtained by MLR and SVM, respectively. The descriptors found in our quantitative structure–activity relationship models are prone to a structural interpretation and support the AH/B System model proposed by Shallenberger and Acree.
Significance of XRCC1 Codon399 polymorphisms in Chinese patients with locally advanced nasopharyngeal carcinoma treated with radiation therapy
Authors: Zhai Xiao‐Ming , Hu Qun‐Chao , Gu Ke , Wang Jian‐Ping , Zhang Jun‐Ning , Wu Yi‐Wei
Published: August 2013

Aim

Little is known about the relationship between XRCC1 Codon399 polymorphisms and radiotherapy (RT) outcomes in patients with nasopharyngeal carcinoma (NPC). We aimed to investigate whether XRCC1 Codon399 polymorphisms were correlated to treatment efficacy and normal tissue toxicity in Chinese patients with locally advanced NPC after RT.

Methods

Sixty eligible patients with NPC stage III–IVa were recruited. Patients received definitive RT, 66–76 Gy. One cycle neoadjuvant chemotherapy with docetaxel and cisplatin regimen was used before RT, two or three cycles for concurrent chemo‐RT followed by two to four cycles adjuvant chemotherapy with the same regimen. Before the treatment, XRCC1 Codon399 polymorphisms were determined by polymerase chain reaction based ligase detection reaction methods.

Results

Six of 60 NPC patients were homozygous for XRCC1 Codon399 Gln/Gln and 35% were heterozygous. The expressions of genotypes were unrelated to gender, age, clinical stage, T stage or N stage. Codon399 Gln/Gln allele correlated with a higher medium‐term tumor regression ratio after RT for primary nasopharyngeal neoplasm and metastatic lymph nodes (>80% vs 40–60%, P < 0.01). Compared with other two genotypes, patients with XRCC1 Codon399 Gln/Gln allele were more likely to obtain complete remission of tumor (100% vs 76 and 67%, P > 0.05). No correlation between XRCC1 Codon399 polymorphisms and acute or late radiation‐induced injury of normal tissues was observed.

Conclusions

The XRCC1 Codon399 Gln/Gln allele may be associated with better tumor regression, and is suggested as a promising predictive factor for outcome for locally advanced NPC. Further study with larger samples and long‐time follow‐up is needed for accurate assessment.
Familial transmission of parental mood disorders: unipolar and bipolar disorders in offspring
Authors: Oquendo Maria A , Ellis Steven P , Chesin Megan S , Birmaher Boris , Zelazny Jamie , Tin Adrienne , Melhem Nadine , Burke Ainsley K , Kolko David , Greenhill Laurence , Stanley Barbara , Brodsky Beth S , Mann J John , Brent David A
Published: August 2013

Objectives

Offspring of depressed parents are at increased risk for psychiatric disorders. Although bipolar disorder (BD) and major depressive disorder (MDD) are both found in the same families, it is not clear whether transmission to offspring of BD or MDD tends to occur from parents with the same mood disorder subtype. Our primary hypothesis was that the offspring of parents with BD would be at increased risk for BD and other comorbid disorders common to BD, such as anxiety and substance use, relative to the offspring of parents with MDD. The offspring of parents with BD versus those with MDD were also hypothesized to be at greater risk for externalizing disorders (i.e., conduct disorder, attention‐deficit hyperactivity disorder, or antisocial personality disorder).

Methods

Parents (n = 320) with mood disorders and their offspring (n = 679) were studied. Adult offspring were administered the Structured Clinical Interview for DSM‐IV Axis I Disorders to establish the presence of psychopathology. Offspring aged 10–18 years were assessed using the School Aged Schedule for Affective Disorders and Schizophrenia, Present and Lifetime version, and parents of children under the age of ten completed the Child Behavioral Checklist. Data were examined using Cox proportional hazard regression.

Results

There was no difference in hazard of mood disorders in the offspring of parents with BD as compared to the offspring of parents with MDD. However, a number of other parent and offspring characteristics increased the risk of mood, anxiety, externalizing, and substance use disorders in the offspring, including self‐reported childhood abuse in the parent or offspring, offspring impulsive aggression, and the age at onset of parental mood disorder.

Conclusions

Mood disorders are highly familial, a finding that appears independent of whether the parent's condition is unipolar or bipolar, suggesting considerable overlap in the heritability of MDD and BD. Although parental characteristics had a limited influence on the risk of offspring psychopathology, reported childhood adversity, be it in the parent or child, is a harbinger of negative outcomes. These risk factors extend previous findings, and are consistent with diathesis–stress conceptualizations.
53BP1 is a novel regulator of angiogenesis in breast cancer
Authors: Li Xiaoyan , Kong Xiangnan , Wang Yang , Yang Qifeng
Published: August 2013

In our previous study, we found that 53BP1 was a tumor suppressor and was associated with prognosis in breast cancer. However, little is known about its role in angiogenesis. In the present study, we aimed to reveal the role of 53BP1 in angiogenesis of breast cancer. With RNA interference and ectopic expression strategies to elucidate the detailed function of 53BP1 in angiogenesis, we observed that ectopic expression of 53BP1 inhibited cellular angiogenesis and 53BP1 RNA interference led to an increase in angiogenesis both in vitro and in vivo. In clinical breast cancer samples, 53BP1 was inversely correlated with CD31, MMP‐2 and MMP‐9 by immunohistochemistry analysis. Furthermore, we showed that the Akt pathway was involved in the antiangiogenesis function of 53BP1. Overall, our findings demonstrate that 53BP1 plays a vital role in inhibiting angiogenesis. These findings suggest that 53BP1 might provide a viable target therapy for breast cancer.