bluuebunny/crossref_metadata_2025 huggingface dataset:
Hierarchical carbon@Ni3S2@MoS2 double core–shell nanorods for high-performance supercapacitors
Authors: Li Laiquan , Yang Hongbin , Yang Jun , Zhang Liping , Miao Jianwei , Zhang Yufei , Sun Chencheng , Huang Wei , Dong Xiaochen , Liu Bin
Published: December 2015

Hierarchical carbon@Ni3S2@MoS2 (C@Ni3S2@MoS2) double core–shell nanorods have been synthesized by a facile hydrothermal method using highly conductive carbon/Ni (C/Ni) nanorods as both the precursor and template.
Organometal halide perovskite thin films and solar cells by vapor deposition
Authors: Ono Luis K. , Leyden Matthew R. , Wang Shenghao , Qi Yabing
Published: December 2015

Vapor based methods provide a promising alternative way to fabricate organometal halide perovskite solar cells.
Piezoelectric properties of CH3NH3PbI3perovskite thin films and their applications in piezoelectric generators
Authors: Kim Yun-Jeong , Dang Tran-Van , Choi Hyung-Jin , Park Byeong-Ju , Eom Ji-Ho , Song Hyun-A , Seol Daehee , Kim Yunseok , Shin Sung-Ho , Nah Junghyo , Yoon Soon-Gil
Published: December 2015

CH3NH3PbI3(MAPbI3) perovskite thin films were applied for piezoelectric generators under various applied pressures, poling field conditions, and switching polarity test.
Light-sensitive ruthenium complex-loaded cross-linked polymeric nanoassemblies for the treatment of cancer
Authors: Dickerson Matthew , Howerton Brock , Bae Younsoo , C. Glazer Edith
Published: December 2015

Cross-linked polymeric nanoassemblies are potential carrier systems for cytotoxic ruthenium complexes, and exhibit a combination of electrostatic and hydrophobic interactions with the metal complexes that impact release rates, release percentages, and biological activity.
Photo-induced chemistry for the design of oligonucleotide conjugates and surfaces
Authors: Vigovskaya Antonina , Abt Doris , Ahmed Ishtiaq , Niemeyer Christof M. , Barner-Kowollik Christopher , Fruk Ljiljana
Published: December 2015

A photocaged diene is introduced at the 5′-end of oligonucleotides using the H-phosphonate approach and subsequently employed for the light-induced conjugation to a protein and the spatially controlled immobilization onto surfaces.
Silk sericin microcapsules with hydroxyapatite shells: protection and modification of organic microcapsules by biomimetic mineralization
Authors: Li Wenhua , Cai Yurong , Zhong Qiwei , Yang Ying , Kundu Subhas C. , Yao Juming
Published: December 2015

Silk protein sericin based organic–inorganic hybrid microcapsules are fabricated by incubating sericin microcapsules with a supersaturated calcium phosphate solution containing citric acid.
Aggregation induced emission amphiphile with an ultra low critical micelle concentration: fabrication, self assembling, and cell imaging
Authors: Li Haiyin , Chang Jiafu , Hou Ting , Li Feng
Published: December 2015

An AIE-active amphiphile containing a tetraphenylethene moiety and a quarternary ammonium salt group, with an ultra low CMC, desirable optical properties, good water dispersibility and excellent biocompatibility, was prepared and investigated, and the as-prepared amphiphile was successfully applied in cell imaging.
Infrared-light induced curing of photosensitive resins through photon up-conversion for novel cost-effective luminescent 3D-printing technology
Authors: Méndez-Ramos J. , Ruiz-Morales J. C. , Acosta-Mora P. , Khaidukov N. M.
Published: December 2015

Cost-effective luminescent 3D-printing technology approach through infrared-laser-induced photon up-conversion in rare-earth-doped materials for “laser-writing” of luminescent 3D printed structures and envisioned applications in nano-photolithography.
Illuminating the electrolyte in light-emitting electrochemical cells
Authors: Mindemark J. , Edman L.
Published: December 2015

The role of the electrolyte in light-emitting electrochemical cells is reviewed, with a focus on how it influences key performance metrics.
Charge generation mechanism of tandem organic light emitting diodes with pentacene/C70 organic heterojunction as the connecting layer
Authors: Guo Qingxun , Sun Hengda , Wang Jiaxiu , Yang Dezhi , Chen Jiangshan , Ma Dongge
Published: December 2015

Charge generation mechanism of a pentacene/C70 planar organic heterojunction is discussed in detail to fabricate high performance tandem OLEDs.
Solution synthesis of GeS and GeSe nanosheets for high-sensitivity photodetectors
Authors: Ramasamy Parthiban , Kwak Dohyun , Lim Da-Hye , Ra Hyun-Soo , Lee Jong-Soo
Published: December 2015

High-sensitivity photodetectors are reported using solution synthesized GeS and GeSe nanosheets.
Autism-associated R451C mutation in neuroligin3 leads to activation of the unfolded protein response in a PC12 Tet-On inducible system
Authors: Ulbrich Lisa , Favaloro Flores Lietta , Trobiani Laura , Marchetti Valentina , Patel Vruti , Pascucci Tiziana , Comoletti Davide , Marciniak Stefan J. , De Jaco Antonella
Published: December 2015

Several forms of monogenic heritable autism spectrum disorders are associated with mutations in the neuroligin genes. The autism-linked substitution R451C in neuroligin3 induces local misfolding of its extracellular domain, causing partial retention in the ER (endoplasmic reticulum) of expressing cells. We have generated a PC12 Tet-On cell model system with inducible expression of wild-type or R451C neuroligin3 to investigate whether there is activation of the UPR (unfolded protein response) as a result of misfolded protein retention. As a positive control for protein misfolding, we also expressed the mutant G221R neuroligin3, which is known to be completely retained within the ER. Our data show that overexpression of either R451C or G221R mutant proteins leads to the activation of all three signalling branches of the UPR downstream of the stress sensors ATF6 (activating transcription factor 6), IRE1 (inositol-requiring enzyme 1) and PERK [PKR (dsRNA-dependent protein kinase)-like endoplasmic reticulum kinase]. Each branch displayed different activation profiles that partially correlated with the degree of misfolding caused by each mutation. We also show that up-regulation of BiP (immunoglobulin heavy-chain-binding protein) and CHOP [C/EBP (CCAAT/enhancer-binding protein)-homologous protein] was induced by both mutant proteins but not by wild-type neuroligin3, both in proliferative cells and cells differentiated to a neuron-like phenotype. Collectively, our data show that mutant R451C neuroligin3 activates the UPR in a novel cell model system, suggesting that this cellular response may have a role in monogenic forms of autism characterized by misfolding mutations.
Combined features for face recognition under illumination variation
Authors: Choi Sang‐Il
Published: December 2015

A robust face recognition method that utilises a set of combined features is proposed to effectively conduct face recognition with images taken under diverse illumination variations. This method extracts discriminant features from different methods, both of which have different characteristics. To exploit the respective advantage of each method, the respective discriminability of the features extracted by each method is measured based on the discriminant distance criterion of each method. The experimental results show that the proposed features result in improved recognition performance under illumination variation.
Destination‐based cooperative jamming in untrusted amplify‐and‐forward relay networks: resource allocation and performance study
Authors: Kuhestani Ali , Mohammadi Abbas
Published: December 2015

In this study, the authors study the problem of secure transmission in two‐hop amplify‐and‐forward systems with an untrusted relay. To prevent the untrusted relay from intercepting the source message and to achieve positive secrecy rate, the destination‐based cooperative jamming technique is used. In this method, the destination sends an intended jamming signal to the relay. This jamming signal helps protecting the source message from being captured reliably at the untrusted relay, while the destination cancels itself intended jamming signal. The optimal power allocation (OPA) strategy is considered for the proposed system. They observe that the objective function is a quasi‐concave function at high signal‐to‐noise‐ratio regimes. Based on this OPA strategy, in the first step, the outage probability of the system is investigated. It is investigated for three cases. In the two cases, either of the source or the destination node is equipped with large‐scale antennas, and in the third case, both of them are equipped with large‐scale antenna arrays. In all the cases, the closed‐form expressions are derived. In the second step, they investigate the ergodic secrecy rate and present the closed‐form solutions for all the mentioned cases. Finally, simulation results indicate the accuracy of the derived equations.
Beam axis detection and alignment for uniform circular array‐based orbital angular momentum wireless communication
Authors: Tian Hui , Liu Ziqiang , Xi Wei , Nie Gaofeng , Liu Liu , Jiang Huiling
Published: December 2015

Orbital angular momentum (OAM) provides a new dimension for multiplexing and consequently can improve the link capacity remarkably. In the scope of radio communication, uniform circular array (UCA) is usually used to generate OAM signals, where beam axis detection and alignment is a key factor that influences the detection of OAM signal and directly determines the capacity of OAM links. This study analyses the beam axis detection and alignment issues under the ideal (noiseless) condition. The authors first clarify the fact that for single‐mode OAM transmission, the intensity of electric field in radial direction is characterised by the Bessel function of the first kind. Inspired by this property, they propose three practical methods for beam axis detection and alignment, that is, double parallelogram array method, double UCA method and single UCA method. Iterative translation and rotation strategy are applied to enhance the precision. Finally, the effectiveness of the proposed methods is justified by simulation.
Physical layer security using massive multiple‐input and multiple‐output: passive and active eavesdroppers
Authors: Al‐nahari Azzam
Published: December 2015

Physical layer security is considered as a promising technique that exploits the channel properties in order to send confidential messages to the legitimate receiver even in the presence of a powerful eavesdropper and the absence of its channel information. In this study, the authors consider the effect of massive multiple‐input and multiple‐output (MMIMO) system operating in TDD mode in improving the physical layer security in the presence of multi‐antennas eavesdropper. The channel state information (CSI) of the eavesdropper is assumed not known at the transmitter side, and also imperfect CSI of the legitimate receiver is assumed. The first important finding is that MMIMO is a valuable technique to combat passive eavesdropping, where it is shown that the achievable secrecy rate increases logarithmically with the number of transmit antennas. However, the eavesdropper can be active and attack the training phase of the legitimate transmitter. As a consequence, this dramatically reduces the achievable secrecy rate. The second contribution of this study is a simple protocol that can effectively detect this attack so that a countermeasure can be taken. Closed‐form expressions for the detection and false‐alarm probabilities are derived. Moreover, the authors analyse the intercept probability and show that asymptotically exponential diversity is achieved.
Discrete‐input continuous‐output memoryless channel capacity of cooperative hierarchical modulation
Authors: Sun Hua , Ng Soon Xin , Hanzo Lajos
Published: December 2015

Hierarchical modulation (HM) is a layered modulation scheme, which is widely employed by the telecommunication industry. The higher flexibility and lower complexity of the HM scheme has its dramatic benefits for wireless communications, hence the achievable performance of cooperation‐aided coded HM has drawn substantial research interests. In this study, a triple‐layer HM‐aided four‐node cooperative communication system is proposed, and its discrete‐input continuous‐output memoryless channel capacity is derived, which is used for finding the optimal position of the relay nodes as well as to design appropriate HM constellations. The authors’ simulation results show that if a rate‐1/2 ‘perfect’ channel code is assumed, the four‐node network becomes capable of conveying a coded HM‐64QAM signal in three time slots at an average signal‐to‐noise ratio of −0.71 dB.
An efficient hierarchical 16‐QAM dynamic constellation to obtain high PSNR reconstructed images under varying channel conditions
Authors: Gangadharappa Mandlem , Kapoor Rajiv , Dixit Hirdesh
Published: December 2015

Startling growth in multimedia services over wireless channels emphasizes the need for bandwidth and power efficient modulation techniques. This study investigates the suitability of hierarchical quadrature amplitude modulation (HQAM) for image transmission over erroneous wireless Gaussian channels. HQAM provides unequal error protection, to compressed and coded image data, transmitted without increasing the required bandwidth, unlike channel coding. A discrete cosine transform based image coder is used to divide the image data bit stream into high‐priority (HP) and low‐priority (LP) sub‐streams for significant and non‐significant data respectively. The ratios between the constellation distances are then dynamically adjusted with the objective to achieve an acceptable bit‐error rate (BER) for HP sub‐stream over varying channel conditions at the cost of increased BER for LP sub‐stream. The work highlights HQAM implementation using conventional quadrature amplitude modulation (QAM) demodulator at the receiver which does not require the knowledge of varying constellation distance ratios at the transmitter. An analysis of 16‐HQAM transmission for different values of distance ratios is presented to obtain high peak signal‐to‐noise ratio (PSNR) values of reconstructed images under poor as well as good channel conditions and the performance is compared qualitatively and quantitatively with 16‐QAM.
Implementation of minimisation techniques to construction optimisation of iron‐core inductor
Authors: Nedić Aleksandar B. , Simović Miodrag V. , Lazarević Zoran M. , Milić Saša D.
Published: December 2015

In this study, the authors propose a modelling algorithm of inductors that provides a powerful tool for solving a variety of engineering optimisation problems. The algorithm has been developed in accordance with desire to consolidate cost benefit, losses minimisation and inductance maximisation, and finding the best manufacturing solution. A non‐linear mathematical model for optimisation of three‐phase, dry type double‐E iron‐core inductor has been presented in this study. Its purpose is to show that design of three‐phase, air‐cooled, network frequency inductors can be obtained using of new, adopted non‐linear modelling algorithm‐MISP (mixed‐integer signomial programming), for minimising cost of materials (or inductor's mass) while ensuring the satisfaction of inductance value together with constraints imposed by overall measures, copper fill factor, maximum allowed induction, current density and temperature rise. The MISP is solved using branch‐and‐bound approach, specially implemented to inductor design problems. To confirm the result obtains by optimisation, inductor has been constructed according to the minimum loss criterion. The application is industry acceptable in cases if there are restrictions on the inductor weight. Also, where core dimensions are known, this approach can be used to design inductor by either maximising the inductance value or minimising total losses.
Sector nulling in planar irregular sub‐arrayed sparse array antennas
Authors: Khan Asim Ali , Brown Anthony Keith
Published: December 2015

This study concerns wide angular sector (higher order) null synthesis in planar irregular sparse antenna arrays when aperture distributed sub‐arrays are used to reduce the computational load. A hybrid optimisation tool has been used to find array element excitations to achieve as low as possible sector nulls for the desired sector width. Performance comparisons have been made for three sub‐array configurations based on the obtained numerical results. Various interference jamming scenarios have been considered including single and dual sectors for single‐dimensional (θ) (1D) and two‐dimensional (θ, ϕ) (2D) nulls. The proposed optimisation scheme has shown to be successful for the synthesis of 1D and 2D sector nulls with depths as low as −100 dB for the given configuration with reduced computational time when compared with the full array. The comparison of achieved null depths for different sub‐array sizes and convergence time has also been presented and discussed.
Temperature–humidity–bias testing on insulated‐gate bipolartransistor modules – failure modes and acceleration due to high voltage
Authors: Zorn Christian , Kaminski Nando
Published: December 2015

The temperature–humidity–bias (THB) test is the standard for accelerated stress testing with respect to corrosion and other humidity driven degradation mechanisms. Usually, 1000 h tests at 85°C and 85% relative humidity are used to predict up to 25 years of operation. The bias is usually limited to 80 V in order to fulfil the respective standards. Nevertheless, THB tests on 1700 V insulated‐gate bipolar transistor (IGBT)‐modules have shown that higher bias is a more severe test condition. The failure analysis confirmed Cu‐ and Ag‐dendrites and corrosion of the aluminium (Al)‐chip‐metallisation as the relevant failure mechanisms. To determine the acceleration factor due to voltage, 1200 V IGBT modules were tested in THB at 780 V (65% of VCES) and 1080 V (90% of VCES). A characteristic degradation consisting of three phases has been identified. The second phase seems to be determined by Al corrosion and an acceleration factor of about two has been estimated from 780 to 1080 V. Within the third phase, the devices stabilised probably due to localised self‐heating. Thus, this degradation mechanism is kind of self‐limiting, but the higher leakage also increases the risk of thermal runaway especially when biased close to the rated collector–emitter voltage.
Impact of route length on the performance of routing and flow admission control algorithms in wireless sensor networks
Authors: Farooq Muhammad Omer , Kunz Thomas
Published: December 2015

In this study, the impact of route length on the performance of a routing protocol and flow admission control is analysed. First, the authors present an end‐to‐end available‐bandwidth‐based proactive routing protocol for ad‐hoc wireless sensor networks. The routing protocol maintains the best data forwarding path in terms of the end‐to‐end available bandwidth. Second, to determine the impact of route length on a routing protocol's performance, they modify the routing protocol. The modified available‐bandwidth‐based protocol trades‐off the end‐to‐end available bandwidth against the route length. Third, they integrate a state‐of‐the‐art flow admission control algorithm with the proposed protocols and a shortest hop‐count‐based protocol. Through simulations they evaluate the following: (i) performance of the proposed protocols and a state‐of‐the‐art available‐bandwidth‐based opportunistic protocol and (ii) the effectiveness of a state‐of‐the‐art flow admission control algorithm over proposed protocols and a shortest hop‐count‐based protocol. The simulation results demonstrate the following drawbacks of not considering the hop‐count metric: longer data forwarding paths, higher number of retransmissions, and reduced effectiveness of the admission control algorithm. The modified available‐bandwidth‐based proactive protocol provides the best overall performance. Therefore, using their results they conclude that route length impacts the performance of routing and flow admission control algorithms, but is not a singularly decisive factor.
Data collection using miniature aerial vehicles in wireless sensor networks
Authors: Mathur Prateek , Nielsen Rasmus H. , Prasad Neeli R. , Prasad Ramjee
Published: December 2015

Energy constraints of sensor nodes in wireless sensor networks (WSNs) is a major challenge and minimising the overall data transmitted across a network using data aggregation, distributed source coding, and compressive sensing have been proposed as mechanisms for energy saving. Similarly, use of mobile nodes capable of relocating within the network has been widely explored for energy saving. In this study, the authors propose a novel method for using miniature aerial vehicles for data collection instead of actively sensing from a deployed network. The proposed mechanism is referred as data collection fly (DCFly). It is suitable for data collection from WSNs deployed in harsh‐undulating terrain with the base station located far from the sensing region. The DCFly is compared with data collection based on multi‐hop data aggregation and data collection with mobile sinks. The numerical results justify that the proposed data collection mechanism is effective and efficient for use in WSNs.
Inadequate Surgical Decompression in Patients with Cervical Myelopathy: A Retrospective Review
Authors: Bhalla Amandeep , Rolfe Kevin W.
Published: December 2015

Study Design

Retrospective study.

Objective

We reviewed cases of surgically treated cervical spondylotic myelopathy (CSM) or chronic, degenerative myelopathy of the subaxial cervical spine to study the incidence of inadequate surgical decompression.

Methods

We included all persons treated at our institution after a first surgical decompression for CSM over a 3-year period. Inadequate original surgical decompression was defined as neurologic decline within 12 months postoperatively and ongoing impingement of the spinal cord with <1-mm change in anteroposterior canal dimension from pre- to postoperative magnetic resonance imaging (MRI) leading to revision decompressive surgery. Revisions for other reasons were not counted as inadequate.

Results

Of 50 patients, 5 (10%) required revision decompression for neurologic decline and inadequate change in space available for the cord on postoperative imaging; 4 patients declined within the first 6 months and 1 patient at 8 months postoperatively. None of the 5 declined further after posterior revision, but none recovered from the interval loss. All 5 had undergone anterior approaches, for an anterior inadequacy rate of 23% (5 of 22). None of the 28 patients having posterior or combined approach declined at 2 years or had <1-mm change on postoperative MRI. The difference between anterior and posterior approaches was statistically significant ( p = 0.018).

Conclusions

The rate of inadequate surgical decompression for CSM was greater than expected in this series and directly associated with an anterior approach. No cases of inadequacy occurred for posterior or combined approaches. Postoperative neuroradiographic imaging such as MRI should be entertained routinely for this entity or at least for anterior-only approaches.
Communication: Investigation of the electron momentum density distribution of nanodiamonds by electron energy-loss spectroscopy
Authors: Feng Zhenbao , Yang Bing , Lin Yangming , Su Dangsheng
Published: December 2015

The electron momentum distribution of detonation nanodiamonds (DND) was investigated by recording electron energy-loss spectra at large momentum transfer in the transmission electron microscope (TEM), which is known as electron Compton scattering from solid (ECOSS). Compton profile of diamond film obtained by ECOSS was found in good agreement with prior photon experimental measurement and theoretical calculation that for bulk diamond. Compared to the diamond film, the valence Compton profile of DND was found to be narrower, which indicates a more delocalization of the ground-state charge density for the latter. Combining with other TEM characterizations such as high-resolution transmission electron spectroscopy, diffraction, and energy dispersive X-ray spectroscopy measurements, ECOSS was shown to be a great potential technique to study ground-state electronic properties of nanomaterials.
Förster resonant energy transfer from an inorganic quantum well to a molecular material: Unexplored aspects, losses, and implications to applications
Authors: Itskos G. , Othonos A. , Choulis S. A. , Iliopoulos E.
Published: December 2015

A systematic investigation of Förster resonant energy transfer (FRET) is reported within a hybrid prototype structure based on nitride single quantum well (SQW) donors and light emitting polymer acceptors. Self-consistent Schrödinger-Poisson modeling and steady-state and time-resolved photoluminescence experiments were initially employed to investigate the influence of a wide structural parameter space on the emission quantum yield of the nitride component. The optimized SQW heterostructures were processed into hybrid structures with spin-casted overlayers of polyfluorenes. The influence of important unexplored aspects of the inorganic heterostructure such as SQW confinement, content, and doping on the dipole-dipole coupling was probed. Competing mechanisms to the FRET process associated with interfacial recombination and charge transfer have been studied and their implications to device applications exploiting FRET across heterointerfaces have been discussed.
Bulk universality of sparse random matrices
Authors: Huang Jiaoyang , Landon Benjamin , Yau Horng-Tzer
Published: December 2015

We consider the adjacency matrix of the ensemble of Erdős-Rényi random graphs which consists of graphs on N vertices in which each edge occurs independently with probability p. We prove that in the regime pN ≫ 1, these matrices exhibit bulk universality in the sense that both the averaged n-point correlation functions and distribution of a single eigenvalue gap coincide with those of the GOE. Our methods extend to a class of random matrices which includes sparse ensembles whose entries have different variances.
Magnetic characteristics of a high-layer-number NiFe/FeMn multilayer
Authors: Paterson G. W. , Gonçalves F. J. T. , McFadzean S. , O'Reilly S. , Bowman R. , Stamps R. L.
Published: December 2015

We report the static and dynamic magnetic characteristics of a high-layer-number NiFe/FeMn multilayer test structure with potential applications in broadband absorber and filter devices. To allow fine control over the absorption linewidths and to understand the mechanisms governing the resonances in a tailored structure similar to that expected to be used in real world applications, the multilayer was intentionally designed to have layer thickness and interface roughness variations. Magnetometry measurements show that the sample has complex hysteresis loops with features consistent with single ferromagnetic film reversals. Characterisation by transmission electron microscopy allows us to correlate the magnetic properties with structural features, including the film widths and interface roughnesses. Analysis of resonance frequencies from broadband ferromagnetic resonance measurements as a function of field magnitude and orientation provide values of the local exchange bias, rotatable anisotropy, and uniaxial anisotropy fields for specific layers in the stack and explain the observed mode softening. The linewidths of the multilayer are adjustable around the bias field, approaching twice that seen at larger fields, allowing control over the bandwidth of devices formed from the structure.
A portable molecular-sieve-based CO2 sampling system for radiocarbon measurements
Authors: Palonen V.
Published: December 2015

We have developed a field-capable sampling system for the collection of CO2 samples for radiocarbon-concentration measurements. Most target systems in environmental research are limited in volume and CO2 concentration, making conventional flask sampling hard or impossible for radiocarbon studies. The present system captures the CO2 selectively to cartridges containing 13X molecular sieve material. The sampling does not introduce significant under-pressures or significant losses of moisture to the target system, making it suitable for most environmental targets. The system also incorporates a significantly larger sieve container for the removal of CO2 from chambers prior to the CO2 build-up phase and sampling. In addition, both the CO2 and H2O content of the sample gas are measured continuously. This enables in situ estimation of the amount of collected CO2 and the determination of CO2 flux to a chamber. The portable sampling system is described in detail and tests for the reliability of the method are presented.
Cryogenic distillation facility for isotopic purification of protium and deuterium
Authors: Alekseev I. , Arkhipov Ev. , Bondarenko S. , Fedorchenko O. , Ganzha V. , Ivshin K. , Kammel P. , Kravtsov P. , Petitjean C. , Trofimov V. , Vasilyev A. , Vasyanina T. , Vorobyov A. , Vznuzdaev M.
Published: December 2015

Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products.
Influence of a magnetic field on the viscosity of a dilute gas consisting of linear molecules
Authors: Hellmann Robert , Vesovic Velisa
Published: December 2015

The viscomagnetic effect for two linear molecules, N2 and CO2, has been calculated in the dilute-gas limit directly from the most accurate ab initio intermolecular potential energy surfaces presently available. The calculations were performed by means of the classical trajectory method in the temperature range from 70 K to 3000 K for N2 and 100 K to 2000 K for CO2, and agreement with the available experimental data is exceptionally good. Above room temperature, where no experimental data are available, the calculations provide the first quantitative information on the magnitude and the behavior of the viscomagnetic effect for these gases. In the presence of a magnetic field, the viscosities of nitrogen and carbon dioxide decrease by at most 0.3% and 0.7%, respectively. The results demonstrate that the viscomagnetic effect is dominated by the contribution of the jj¯ polarization at all temperatures, which shows that the alignment of the rotational axes of the molecules in the presence of a magnetic field is primarily responsible for the viscomagnetic effect.
Surface phonon dispersion on hydrogen-terminated Si(110)-(1 × 1) surfaces studied by first-principles calculations
Authors: Matsushita Stephane Yu , Hu Chunping , Kawamoto Erina , Kato Hiroki , Watanabe Kazuyuki , Suto Shozo
Published: December 2015

We studied the lattice constants, surface-phonon dispersion curves, spectral densities, and displacement vectors of the hydrogen-terminated Si(110)-(1 × 1) [H:Si(110)-(1 × 1)] surface using the first-principles calculations within the framework of density functional theory (DFT). The symmetry of the H:Si(110)-(1 × 1) surface belongs to the two-dimensional space group p2mg, which has two highly symmetric and orthogonal directions, ΓX¯ and ΓX′¯, with the glide planes along the ΓX¯ direction. Because glide symmetry separates the even and odd surface phonon modes, we mapped the even surface modes in the first surface Brillouin zone (SBZ) and the odd surface modes in the second SBZ using the spectral densities and displacement vectors. The surface phonon modes were analyzed with respect to their physical origin, spatial localization properties, polarization, and the charge density of their electronic states. Our calculated surface phonon modes were in good agreement with recent high-resolution electron-energy-loss spectroscopy data in the first and second SBZs of the ΓX¯ direction. In the SBZ of the ΓX′¯ direction, our calculated surface phonon modes agree well with the data in the energy region below 65 meV but are not satisfactorily compatible with those in the stretching and bending modes. In addition, we discuss the microscopic nature of the surface phonon dispersion of the H:Si(110)-(1 × 1) surface using the phonon eigen modes.
Charge movement in a GaN-based hetero-structure field effect transistor structure with carbon doped buffer under applied substrate bias
Authors: Pooth Alexander , Uren Michael J. , Cäsar Markus , Martin Trevor , Kuball Martin
Published: December 2015

Charge trapping and transport in the carbon doped GaN buffer of a GaN-based hetero-structure field effect transistor (HFET) has been investigated under both positive and negative substrate bias. Clear evidence of redistribution of charges in the carbon doped region by thermally generated holes is seen, with electron injection and capture observed during positive bias. Excellent agreement is found with simulations. It is shown that these effects are intrinsic to the carbon doped GaN and need to be controlled to provide reliable and efficient GaN-based power HFETs.
Size effects in the magnetic properties of ε-Fe2O3 nanoparticles
Authors: Dubrovskiy A. A. , Balaev D. A. , Shaykhutdinov K. A. , Bayukov O. A. , Pletnev O. N. , Yakushkin S. S. , Bukhtiyarova G. A. , Martyanov O. N.
Published: December 2015

We report the results of comparative analysis of magnetic properties of the systems based on ε-Fe2O3, nanoparticles with different average sizes (from ∼3 to 9 nm) and dispersions. The experimental data for nanoparticles higher than 6–8 nm in size are consistent with the available data, specifically, the transition to the magnetically ordered state occurs at a temperature of ∼500 K and the anomalies of magnetic properties observed in the range of 80–150 K correspond to the magnetic transition. At the same time, Mőssbauer and ferromagnetic resonance spectroscopy data as well as the results of static magnetic measurements show that at room temperature all the investigated samples contain ε-Fe2O3 particles that exhibit the superparamagnetic behavior. It was established that the magnetic properties of nanoparticles significantly change with a decrease in their size to ∼6 nm. According to high-resolution electron microscopy and Mőssbauer spectroscopy data, the particle structure can be attributed to the ε–modification of trivalent iron oxide; meanwhile, the temperature of the magnetic order onset in these particles is increased, the well-known magnetic transition in the range of 80–150 K does not occur, the crystallographic magnetic anisotropy constant is significantly reduced, and the surface magnetic anisotropy plays a decisive role. This is apparently due to redistribution of cations over crystallographic positions with decreasing particle size, which was established using Mössbauer spectra. As the particle size is decreased and the fraction of surface atoms is increased, the contribution of an additional magnetic subsystem formed in a shell of particles smaller than ∼4 nm becomes significant, which manifests itself in the static magnetic measurements as paramagnetic contribution.
Two planar polishing methods by using FIB technique: Toward ultimate top-down delayering for failure analysis
Authors: Wang D. D. , Huang Y. M. , Tan P. K. , Feng H. , Low G. R. , Yap H. H. , He R. , Tan H. , Dawood M. K. , Zhao Y. Z. , Lam J. , Mai Z. H.
Published: December 2015

Presently two major limiting factors are hindering the failure analysis (FA) development during the semiconductor manufacturing process and technology improvement: (1) Impossibility of manual polishing on the edge dies due to the amenability of layer peeling off; (2) Abundant demand of multi-locations FA, especially focusing different levels of layers simultaneously. Aiming at resolving these limitations, here we demonstrate two unique high precision polishing methods by using focused ion beam (FIB) technique. One is the vertical top down chemical etching at the aimed location; the other one is the planar top down slicing. Using the FIB for delayering not only solves these problems mentioned above, but also offers significant advantages over physical planar polishing methods such as: (1) having a better control of the delayering progress, (2) enabling precisely milling at a region of interest, (3) providing the prevention of over-delayering and (4) possessing capability to capture images at the region of interest simultaneously and cut into the die directly to expose the exact failure without damaging other sections of the specimen.
Physics Nobel Prize honors the discovery of neutrino flavor oscillations
Authors: Miller Johanna L.
Published: December 2015

The hard-won result that the elusive particles can change their identities has far-reaching implications.
Diatomic molecules, a window onto fundamental physics
Authors: DeMille David
Published: December 2015

Thanks to the rich structure of their energy levels, molecules can be exquisite probes of time-reversal-symmetry violation, the constancy of the proton-to-electron mass ratio, and more.
Quantum memory for photons
Authors: Afzelius Mikael , Gisin Nicolas , de Riedmatten Hugues
Published: December 2015

The quantum state of a photon can be transferred to a single trapped atom or to a bunch of atoms in a gas or solid and be stored for later release on demand.
History of the ribosome and the origin of translation
Authors: Petrov Anton S. , Gulen Burak , Norris Ashlyn M. , Kovacs Nicholas A. , Bernier Chad R. , Lanier Kathryn A. , Fox George E. , Harvey Stephen C. , Wartell Roger M. , Hud Nicholas V. , Williams Loren Dean
Published: December 2015

Significance

The ribosome, in analogy with a tree, contains a record of its history, spanning 4 billion years of life on earth. The information contained within ribosomes connects us to the prehistory of biology. Details of ribosomal RNA variation, observed by comparing three-dimensional structures of ribosomes across the tree of life, form the basis of our molecular-level model of the origins and evolution of the translational system. We infer many steps in the evolution of translation, mapping out acquisition of structure and function, revealing much about how modern biology originated from ancestral chemical systems.
Neural evidence that three dimensions organize mental state representation: Rationality, social impact, and valence
Authors: Tamir Diana I. , Thornton Mark A. , Contreras Juan Manuel , Mitchell Jason P.
Published: December 2015

Significance

This study uses advanced functional neuroimaging analyses to test both existing and novel psychological theories about how we understand others’ minds. Analyses show that three dimensions—rationality, social impact, and valence—account for almost half of the variation in the neural representation of mental states, the most comprehensive theory to date regarding our ability to think about others’ minds. These findings both inform long-standing debates within social psychology about theory of mind and generate testable predictions about how our neural hardware supports our ability to mentalize.
ClpB N-terminal domain plays a regulatory role in protein disaggregation
Authors: Rosenzweig Rina , Farber Patrick , Velyvis Algirdas , Rennella Enrico , Latham Michael P. , Kay Lewis E.
Published: December 2015

Significance

ClpB/Hsp100 chaperones protect cells from the devastating effects of protein inactivation and aggregation arising from extreme stress. This function is accomplished first by binding to the aggregates and then forcibly unraveling individual proteins by passing them through the central channel in the hexameric chaperones. Here, we investigate the role of the ClpB/Hsp100 N-terminal domain (NTD) in protein disaggregation. Our results demonstrate that ClpB recognizes exposed hydrophobic stretches in unfolded or aggregated client proteins via a substrate-binding groove in its NTD. We further show that the NTD has regulatory roles that include blocking the translocation channel in the absence of substrate and destabilizing client proteins upon binding, thus priming them for subsequent unfolding and disaggregation.
Direct mapping of local director field of nematic liquid crystals at the nanoscale
Authors: Xia Yu , Serra Francesca , Kamien Randall D. , Stebe Kathleen J. , Yang Shu
Published: December 2015

Significance

It has been challenging to directly probe the molecular-scale organization of nonglassy nematic liquid crystal (LC) molecules without altering the LC directors. Here, we design and synthesize a new type of stable nematic liquid crystal monomer (LCM) system with strong dipole–dipole interactions. The new LCMs can achieve faithful anchoring and alignment control at various boundaries, analogous to that of small molecule LCs. Upon photo-cross-linking, the orientational order of mesogens is effectively and faithfully locked, allowing for direct visualization of the LC director field and defect structures by scanning electron microscopy (SEM) with 100-nm resolution. Further, we use SEM imaging to calculate the extrapolation length of the LCM for planar and homeotropic anchoring.
ADP-stimulated contraction: A predictor of thin-filament activation in cardiac disease
Authors: Sequeira Vasco , Najafi Aref , Wijnker Paul J. M. , dos Remedios Cristobal G. , Michels Michelle , Kuster Diederik W. D. , van der Velden Jolanda
Published: December 2015

Significance

Diastolic dysfunction is characteristic of patients with cardiomyopathy. Evidence indicates that diseased hearts show basal sarcomeric activation capable of impairing diastolic performance. By activating human cardiomyopathy muscle in ADP-containing solutions without Ca
2+
, we showed that actin–myosin blockade is disrupted. This may be caused by the presence of mutations and/or the reduced phosphorylation of myofilament proteins. Our mechanistic study supports the novel idea that protein kinase A-target phosphorylation and myosin-binding protein C regulate the OFF–ON transition of the thin filaments. ADP increased myofilament force and stiffness in the presence of Ca
2+
in cardiomyopathy samples, suggesting this condition limits muscle relaxation through increased actin–myosin interactions. We conclude that ADP-stimulated contraction can be used to reveal conformational changes in the three-state model of thin-filament activation.
Non-bee insects are important contributors to global crop pollination
Authors: Rader Romina , Bartomeus Ignasi , Garibaldi Lucas A. , Garratt Michael P. D. , Howlett Brad G. , Winfree Rachael , Cunningham Saul A. , Mayfield Margaret M. , Arthur Anthony D. , Andersson Georg K. S. , Bommarco Riccardo , Brittain Claire , Carvalheiro Luísa G. , Chacoff Natacha P. , Entling Martin H. , Foully Benjamin , Freitas Breno M. , Gemmill-Herren Barbara , Ghazoul Jaboury , Griffin Sean R. , Gross Caroline L. , Herbertsson Lina , Herzog Felix , Hipólito Juliana , Jaggar Sue , Jauker Frank , Klein Alexandra-Maria , Kleijn David , Krishnan Smitha , Lemos Camila Q. , Lindström Sandra A. M. , Mandelik Yael , Monteiro Victor M. , Nelson Warrick , Nilsson Lovisa , Pattemore David E. , de O. Pereira Natália , Pisanty Gideon , Potts Simon G. , Reemer Menno , Rundlöf Maj , Sheffield Cory S. , Scheper Jeroen , Schüepp Christof , Smith Henrik G. , Stanley Dara A. , Stout Jane C. , Szentgyörgyi Hajnalka , Taki Hisatomo , Vergara Carlos H. , Viana Blandina F. , Woyciechowski Michal
Published: December 2015

Significance

Many of the world’s crops are pollinated by insects, and bees are often assumed to be the most important pollinators. To our knowledge, our study is the first quantitative evaluation of the relative contribution of non-bee pollinators to global pollinator-dependent crops. Across 39 studies we show that insects other than bees are efficient pollinators providing 39% of visits to crop flowers. A shift in perspective from a bee-only focus is needed for assessments of crop pollinator biodiversity and the economic value of pollination. These studies should also consider the services provided by other types of insects, such as flies, wasps, beetles, and butterflies—important pollinators that are currently overlooked.
Conservatives negatively evaluate counterstereotypical people to maintain a sense of certainty
Authors: Stern Chadly , West Tessa V. , Rule Nicholas O.
Published: December 2015

Significance

People often evaluate others in a negative manner when they do not fit the stereotypes that are generally believed about their group. Here, we not only show that political conservatives are more likely to negatively evaluate people who deviate from stereotypes than are liberals, but also explain why. Previous research has heavily emphasized that people endorse stereotypes because they hold negative attitudes toward members of minority groups and because doing so helps to maintain the current structure of society. In contrast to these perspectives, we demonstrate that conservatives negatively evaluate and economically penalize people who deviate from stereotypes because those stereotypes help them to efficiently categorize people into groups, which provides a greater sense of certainty about the world.
Nck influences preosteoblastic/osteoblastic migration and bone mass
Authors: Aryal A.C Smriti , Miyai Kentaro , Izu Yayoi , Hayata Tadayoshi , Notomi Takuya , Noda Masaki , Ezura Yoichi
Published: December 2015

Significance

Osteoporosis is a major health problem worldwide, as the aging population is soaring. However, molecules involved in the regulation of bone remodeling are still incompletely understood. Nck (noncatalytic region of tyrosine kinase) is an adaptor molecule linking cytoskeleton and cell motility. We now identify that Nck regulates cell migration in vitro as well as in vivo and regulates bone mass via bone formation activity. Nck positively regulates repair of bone injury. This discovery provides a unique insight into the understanding of bone remodeling.
Human genetic basis of interindividual variability in the course of infection
Authors: Casanova Jean-Laurent
Published: December 2015

Significance

Pasteur’s germ theory of disease initially seemed to have resolved the long-standing antagonism between the proponents of intrinsic and extrinsic disease mechanisms. However, by the turn of the 20th century, it had become clear that each microbe killed only a small minority of infected individuals. Infectious diseases killed half of all children before the age of 15 y, but this enormous burden was caused by the dazzling diversity of pathogens rather than by the potency of individual pathogens. The key problem concerning pediatric infectious diseases thus was identified: their pathogenesis. A human genetic theory of infectious diseases has emerged gradually from clinical and epidemiological studies, building on many elegant studies in plants and animals.