bluuebunny/crossref_metadata_2025 huggingface dataset:
Trap states in multication mesoscopic perovskite solar cells: A deep levels transient spectroscopy investigation
Authors: Polyakov A. Y. , Smirnov N. B. , Shchemerov I. V. , Saranin D. S. , Le T. S. , Didenko S. I. , Kuznetsov D. V. , Agresti A. , Pescetelli S. , Matteocci F. , Di Carlo A.
Published: December 2018

This work presents a study of trap levels in a mesoscopic multication lead halide perovskite solar cell structure. The investigation is performed by combining capacitance measurements, admittance measurements, Deep Level Transient Spectroscopy (DLTS), and Optical DLTS. We found a donor level with an energy of 0.2 eV below the conduction band of perovskite. The donor density reaches a concentration of 1018 cm−3 in the accumulation region present at the interface between the perovskite and transporting layers. Other two deep trap levels are found with energies of 0.57 eV and 0.74 eV. The first level is related to a hole trap while the second one to an electron trap.
Biocompatible and degradable gelatin dielectric based low-operating voltage organic transistors for ultra-high sensitivity NH3 detection
Authors: Zhuang Xinming , Zhang Dayong , Wang Xiaolin , Yu Xinge , Yu Junsheng
Published: December 2018

We developed an ultra-high sensitive ammonia (NH3) gas sensor that incorporates a biocompatible/degradable gelatin dielectric layer in a top-contact organic thin-film transistor. The sensitivity study of the gas sensor involves detecting the saturation current change with analyte concentrations, exhibiting a saturation current changing from 17.6% to 45.1% for the concentration of NH3 from 500 ppb to 30 ppm. Importantly, this type of sensing platform shows an excellent detecting limit of 174.0 ppb with a low operating voltage of 4 V. To understand the mechanism of this phenomenon, we fabricated another group of devices that incorporates an additional thin layer of polystyrene covered on top of the gelatin layer. The response sensitivity of this type of sensor is only 5.1% for the NH3concentration of 30 ppm. Systematic studies including morphology analysis of the organic films and electrical properties of the sensors were performed. The results indicate that the functional groups on the gelatin dielectric surface groups have ability to adsorb NH3 analyte, thereby leading to a superior sensing performance. This work demonstrates that the biocompatible/degradable gelatin with unique functional groups is applicable for readily manufacturable low-operating voltage and high-performance thin-film transistor-based gas sensors.
Stochastic electron heating in the laser and quasi-static electric and magnetic fields
Authors: Zhang Yanzeng , Krasheninnikov S. I. , Knyazev Alexey
Published: December 2018

The dynamics of relativistic electrons in the intense laser radiation and quasi-static electromagnetic fields both along and across the laser propagating direction are studied in the 3/2 dimensional (3/2D) Hamiltonian framework. It is shown that the unperturbed oscillations of the relativistic electron in these electric fields could exhibit a long tail of the amplitude of harmonics which makes an onset of stochastic electron motion be a primary candidate for electron heating. Chirikov-like mappings which describe the recurrence relations of electron energy and time passing through zero canonical momentum plane are derived, and then, the criteria for instability are obtained. It follows that for both transverse and longitudinal electric fields, there exist upper limits of the stochastic electron energy depending on the laser intensity and electric field strength. These maximum energies could be increased by a weak electric field. However, the maximum energy is reduced for the superluminal phase velocity in both cases. The impacts of the magnetic fields on the electron dynamics are different for these two cases and discussed qualitatively. These analytic results are confirmed by the numerical simulations of solving the 3/2D Hamiltonian equations directly.
Generalised Navier boundary condition for a volume of fluid approach using a finite-volume method
Authors: Boelens Arnout M. P. , de Pablo Juan J.
Published: December 2018

In this work, an analytical volume of fluid implementation of the generalised Navier boundary condition is presented based on the Brackbill surface tension model. The model is validated by simulations of droplets on a smooth surface in a planar geometry. Looking at the static behavior of the droplets, it is found that there is a good match between the droplet shape resolved in the simulations and the theoretically predicted shape for various values of the Young’s angle. Evaluating the spreading of a droplet on a completely wetting surface, the Voinov-Tanner-Cox law (θ ∝ Ca1/3) can be observed. In addition, the scaling of the droplet radius as a function of time follows r ∝ t1/2, suggesting that spreading is limited by inertia. These observations are made without any fitting parameters except the slip length.
Triangular lattice pattern with invisible Kagome lattice in dielectric barrier discharge system
Authors: Sun Haoyang , Dong Lifang , Fan Weili , Mi Yanlin , Liu Binbin , Huang Jiayu , Li Caixia , Pan Yuyang
Published: December 2018

We present the triangular lattice pattern with the invisible Kagome lattice in the dielectric barrier discharge system with two water electrodes for the first time. The spatio-temporal dynamics studied by an intensified charge-coupled device (ICCD) show that the complex pattern is composed of four different sublattices: Kagome lattice, halos, and big and small spots (B and S). The invisible Kagome lattice is similar to the dark discharge because of its spatio-temporal randomness. Based on the novel discharges (B and S) occurring at the falling edge of applied voltage, the dynamics of surface charges is investigated and demonstrated with a high speed video camera and photomultiplier tubes. Furthermore, the formation of restricted random structures is considered to be the effect of previous discharges which rearrange the surface charges.
Representing local atomic environment using descriptors based on local correlations
Authors: Samanta Amit
Published: December 2018

Statistical learning of material properties is an emerging topic of research and has been tremendously successful in areas such as representing complex energy landscapes as well as in technologically relevant areas, like identification of better catalysts and electronic materials. However, analysis of large data sets to efficiently learn characteristic features of a complex energy landscape, for example, depends on the ability of descriptors to effectively screen different local atomic environments. Thus, discovering appropriate descriptors of bulk or defect properties and the functional dependence of such properties on these descriptors remains a difficult and tedious process. To this end, we develop a framework to generate descriptors based on many-body correlations that can effectively capture intrinsic geometric features of the local environment of an atom. These descriptors are based on the spectrum of two-body, three-body, four-body, and higher order correlations between an atom and its neighbors and are evaluated by calculating the corresponding two-body, three-body, and four-body overlap integrals. They are invariant to global translation, global rotation, reflection, and permutations of atomic indices. By systematically testing the ability to capture the local atomic environment, it is shown that the local correlation descriptors are able to successfully reconstruct structures containing 10-25 atoms which was previously not possible.
First principles studies of self-diffusion processes on metallic lithium surfaces
Authors: Gaissmaier Daniel , Fantauzzi Donato , Jacob Timo
Published: December 2018

Due to the theoretical high specific capacity (3860 mAh/g) and the low standard electrode potential (−3.040 V vs. standard hydrogen electrode), rechargeable lithium metal batteries are considered as excellent energy storage systems. Unfortunately, security concerns related to dendrite formation during charge/discharge cycles still hinder the commercial use of Li metal-based batteries. Using density functional theory, we have studied the bulk and surface properties of metallic lithium at an atomistic level. In this process, bcc Li(100) proved to be the most stable metallic lithium surface. Subsequently, possible self-diffusion mechanisms on perfect and imperfect Li(100) surfaces were examined. For this purpose, nudged elastic band calculations were performed to characterize the respective diffusion processes and to determine the relevant pre-exponential factors and activation barriers. On the basis of the acquired data, it became possible to derive activation temperatures and reaction rates for the respective processes, which are useful for experimental verification as well as for the implementation in long-scale kinetic Monte Carlo simulations.
Formation of hot hydrogen atoms from superexcited states of acetylene
Authors: Kumagai Yoshiaki , Odagiri Takeshi , Nakano Motoyoshi , Suzuki Isao H. , Hosaka Kouichi , Kitajima Masashi , Kouchi Noriyuki
Published: December 2018

The cross sections for the formation of the H(2p) and H(2s) atoms, σ2p and σ2s, respectively, in photoexcitation of C2H2 were obtained in an absolute scale for studying formation and decay of superexcited states in the extreme ultraviolet range. Several superexcited states of C2H2 including multiply excited states were found in the curve of the σ2p cross sections as a function of the incident photon energy. The same states seem to contribute to the variation in the σ2s cross sections as well, which can be ascribed to the non-adiabatic transitions between the 2p and 2s channels. The Σ/Π symmetry-resolved cross sections for the H(2s) atom formation, σ2sΣ and σ2sΠ, were also obtained on an absolute scale. The coupling between the Σu+1 and 1Πu states was found to be small.
Modulated heat conduction in a two-layer dielectric system with dynamical interface thermal resistance
Authors: Alaili Kamal , Ordonez-Miranda Jose , Ezzahri Younès
Published: December 2018

Heat conduction in a two-layer dielectric system excited with a laser beam of modulated intensity is studied in terms of a dynamical interface thermal resistance predicted by the phonon Boltzmann transport equation under the gray relaxation time approximation. This is done by using accurate expressions for both the modulated temperature and heat flux profiles, which describe both the diffusive and ballistic regimes of heat transport. It is shown that (i) for modulation frequencies much smaller than the phonon collision frequency f1 of the finite layer, the values of this dynamical resistance in the pure ballistic regime agree well with those of the diffuse mismatch model, while they differ by about 10% in the diffusive one. (ii) In the diffusive regime, the thermal resistance reaches a maximum at the characteristic modulation frequency fc≃(10/2π)(l1/L)2f1, where l1 and L are the phonon mean free path and thickness of the finite layer, respectively. This maximum thermal resistance is associated with the minimum of the modulated heat flux at the interface. The theoretical basis is used to establish a methodology to determine the dominant thermal relaxation time and phonon mean free path of the finite layer. The obtained results can thus be applied for describing the modulated heat conduction in dielectric thin films through the comparison of our theoretical model with experimental data measured by thermoreflectance or other relevant photothermal techniques.
Screen printed, large area bifacial N-type back junction silicon solar cells with selective phosphorus front surface field and boron doped poly-Si/SiOx passivated rear emitter
Authors: Ok Young-Woo , Tam Andrew M. , Huang Ying-Yuan , Yelundur Vijay , Das Arnab , Payne Adam M. , Chandrasekaran Vinodh , Upadhyaya Ajay D. , Jain Aditi , Rohatgi Ajeet
Published: December 2018

This paper reports on the effect of screen printed metallization on the passivation quality of a boron doped poly-Si/SiOx passivated contact (PC) structure composed of a very thin Si oxide (∼15 Å) capped with boron doped poly-Si. Our boron doped poly-Si/SiOx passivated contact (p-Poly Si/SiOx PC) with a SiNx capping layer gave excellent surface passivation with a very low saturation current density of ∼5 fA/cm2. After screen printed metallization on poly-Si with a metal coverage of ∼10%, this value increased to ∼17 fA/cm2. This paper also demonstrates the fabrication of screen printed, large area (239 cm2), high efficiency (∼21%) n-base bifacial back junction Si solar cells with p-Poly-Si/SiOx PC on the rear and a phosphorus implanted n++-n+ selective front surface field. Detailed analysis is performed to quantify recombination and extract the saturation current density contributions (J0) from each layer of the cell including the metallized front surface field and the tunnel oxide passivated contact. Finally, 2D device modeling of this back junction cell is performed by implementing a simple approach which replaces the p-Poly-Si/SiOx PC by an equivalent p-n junction with the same J0 and gives a good match between the measured and simulated cell parameters using the extracted J0 and recombination velocity values.
Communication: Gibbs phenomenon and the emergence of the steady-state in quantum transport
Authors: Zwolak Michael
Published: December 2018

Simulations are increasingly employing explicit reservoirs—internal, finite regions—to drive electronic or particle transport. This naturally occurs in simulations of transport via ultracold atomic gases. Whether the simulation is numerical or physical, these approaches rely on the rapid development of the steady state. We demonstrate that steady state formation is a manifestation of the Gibbs phenomenon well-known in signal processing and in truncated discrete Fourier expansions. Each particle separately develops into an individual steady state due to the spreading of its wave packet in energy. The rise to the steady state for an individual particle depends on the particle energy—and thus can be slow—and ringing oscillations appear due to filtering of the response through the electronic bandwidth. However, the rise to the total steady state—the one from all particles—is rapid, with time scale π/W, where W is the bandwidth. Ringing oscillations are now also filtered through the bias window, and they decay with a higher power. The Gibbs constant—the overshoot of the first ring—can appear in the simulation error. These results shed light on the formation of the steady state and support the practical use of explicit reservoirs to simulate transport at the nanoscale or using ultracold atomic lattices.
Reproduction of surface-enhanced resonant Raman scattering and fluorescence spectra of a strong coupling system composed of a single silver nanoparticle dimer and a few dye molecules
Authors: Itoh Tamitake , Yamamoto Yuko S.
Published: December 2018

The spectral changes in surface-enhanced resonant Raman scattering (SERRS) and surface enhanced fluorescence (SEF) of single silver nanoparticle dimers adsorbed by near-single dye molecules are reproduced under strong coupling regimes. For the reproduction, the enhancement and quenching factors in SERRS and SEF are derived from the Purcell factors including both radiative and nonradiative plasmon modes. The Purcell factors are estimated using the coupling energies obtained by analyzing the spectral changes in plasmon resonance during SERRS and SEF decay processes on the basis of a classical hybridization model. The model is composed of a plasmon and a molecular exciton with phonon replicas accurately representing the molecular multi-level system. The reproduced SERRS spectral changes are consistent with the experimental ones. Furthermore, the calculated SEF spectral changes can reproduce the experimental ones by phenomenologically assuming transitions from ultra-fast SEF to conventional SEF with decreasing coupling energies.
Implementation of full-area-deposited electron-selective TiOx layers into silicon solar cells
Authors: Titova Valeriya , Schmidt Jan
Published: December 2018

We examine two different silicon solar cell designs featuring full-area electron-selective contacts based on ultrathin (2–3 nm) titanium oxide (TiOx) films deposited by atomic layer deposition. The first cell design applies a layer stack to the cell front, which is composed of an ultrathin intrinsic amorphous silicon (i-a-Si:H) layer for interface passivation, the TiOx film and an indium tin oxide (ITO) layer to provide a good lateral conductance for electrons to the metal fingers. Whereas carrier lifetime measurements on test structures promise high implied open-circuit voltages Voc up to 726 mV, the realized solar cells achieve disappointingly low Voc values <400 mV. The J-V parameters of this cell type are negatively affected by a reverse diode occurring due to the contacting of the TiOx by the high-work function ITO layer. In the second cell type, we implement a layer stack to the cell rear, which is composed of an ultrathin silicon oxide (SiOy) layer, the TiOx film and a full-area-deposited aluminum (Al) layer. Initial Voc values of these cells are relatively low (<600 mV), but improve significantly after annealing at 350°C. The best cell featuring a SiOy/TiOx/Al rear contact achieves an open-circuit voltage of 661 mV and an efficiency of 20.3%. No reverse diode is observed, which is attributed to the lower work function of the Al compared to ITO in the first cell design. From internal quantum efficiency measurements, we extract a rear surface recombination velocity Srear of (52±20) cm/s for our best cell, which is well compatible with efficiencies exceeding 23%.
The interaction between lithium acceptors and gallium donors in zinc oxide
Authors: Sky T. N. , Johansen K. M. , Frodason Y. K. , Svensson B. G. , Vines L.
Published: December 2018

Diffusion of lithium (Li) in uniformly gallium (Ga)-doped monocrystalline bulk zinc oxide (ZnO) is studied over a wide temperature range (500–1150°C) and is demonstrated to be dictated by the distribution of Ga. Below 800°C, the indiffusion of Li from a Li-doped ZnO sputtered film into n+ single crystalline ZnO yields an abrupt and compensated Li-doped box region with the Li concentration matching the free-electron concentration, in accordance with several previous experimental and theoretical reports. However, experimental observations of Li-diffusion at higher temperatures reveal a dissociative diffusion mechanism for heat treatments up to 1150°C. By employing a reaction-diffusion model that includes both Li and Ga, a dissociation energy of 4.6 eV is obtained from the experimental Li diffusion data. This is in excellent agreement with theoretical results for the dissociation of (LiZnGaZn)0 (4.8 eV) into Lii+ and (GaZnVZn)− and suggests that this neutral and stable acceptor-donor pair prevails in Li- and Ga-doped ZnO.
Carboxylic acids in aqueous solutions: Hydrogen bonds, hydrophobic effects, concentration fluctuations, ionization, and catalysis
Authors: Gailus Torsten , Krah Holger , Kühnel Volker , Rupprecht Andreas , Kaatze Udo
Published: December 2018

In the frequency range between 100 kHz and 2 GHz, ultrasonic absorption spectra have been measured for a series of carboxylic acids from formic to enanthic acid, including constitutional isomers. Also investigated have been the spectra for mixtures with water of short-chain formic, acetic, propionic, butyric, and isobutyric acid, in each case covering the complete composition range. The neat carboxylic acids feature two Debye-type relaxation terms with relaxation times between 5.6 and 260 ns as well as 0.14 and 1.4 ns, respectively, at room temperature. Depending on the composition, mixtures with water reveal an additional Debye relaxation term in the intermediate frequency range (acetic acid) or a term subject to a relaxation time distribution (propionic, butyric, and isobutyric acid). The relaxations of the neat acids are assigned to the equilibrium between monomers and single-hydrogen-bonded linear dimers and between linear and twofold-hydrogen-bonded cyclic dimers. The latter equilibrium is considerably catalyzed by hydronium and carboxylate ions. Several mixtures with water indicate one of the up to three Debye relaxations to reflect the protolysis of the organic acid. The term with underlying relaxation time distribution is due to noncritical fluctuations in the local concentrations. The Debye relaxations are evaluated to yield the parameters of the relevant elementary chemical reactions, such as the rate and equilibrium constants and the isentropic reaction volumes. A comparison of the correlation length of concentration fluctuations with data for other aqueous systems confirms the idea that the hydrophobic part of the organic constituent promotes the formation of a micro-heterogeneous liquid structure, whereas the hydrophilic moiety is of minor importance in this respect. The high-frequency limiting absorption suggests the equilibrium between conformers of linear dimers to contribute to the spectra well above the frequency range of measurements.
Characterization of magnetomechanical properties in FeGaB thin films
Authors: Dong Cunzheng , Li Menghui , Liang Xianfeng , Chen Huaihao , Zhou Haomiao , Wang Xinjun , Gao Yuan , McConney Michael E. , Jones John G. , Brown Gail J. , Howe Brandon M. , Sun Nian X.
Published: December 2018

Layered magnetic/piezoelectric heterostructures have drawn a great amount of interest for their potential use in ultra-sensitive magnetoelectric (ME) sensors, ME antennas, voltage tunable inductors, magnetic tunable resonators, etc. It is critically important to characterize the saturation magnetostriction, piezomagnetic coefficient, ΔE effect, and magnetomechanical coupling factor of magnetic thin films, which determine the performance of these ME devices. In this work, a sensitive system has been developed to measure these magnetomechanical properties, on which several different magnetostrictive thin films on the silicon substrate cantilever were characterized. A 0.015 ppm limit of detection of the magnetostriction tester and a frequency resolution of 0.01 Hz of the ΔE tester have been achieved. After magnetic anneal treatment, a record high piezomagnetic coefficient of 12 ppm/Oe, a giant magnetic field induced Young's modulus change of 153 GPa, and a high effective magnetomechanical coupling factor of 0.84 have been measured in FeGaB thin films.
First-order nonadiabatic couplings in extended systems by time-dependent density functional theory
Authors: Zhang Xu , Lu Gang
Published: December 2018

We propose an ab initio formulation that enables a rigorous calculation of the first-order nonadiabatic couplings (NAC) between electronic states based on time-dependent density functional theory in conjunction with planewave bases, projector augmented-wave pseudopotentials, and hybrid exchange-correlation functionals. The linear and quadratic time-dependent response theory is used to derive analytic expressions for the NAC matrix elements. In contrast to the previous formulation in atomic basis sets, the present formulation eliminates explicit references to Kohn-Sham virtual orbitals. With the introduction of Lagrangian functionals, the present formulation circumvents expensive derivative calculations of Kohn-Sham orbitals with respect to ionic coordinates. As a validation of the formulation, the NAC matrix elements of small molecules LiH and HeH+ are calculated and compared to previous results with the atomic orbital basis. This development paves the way for accurate ab initio nonadiabatic molecular dynamics in extended systems.
Perspective: Preservation of coherence in photophysical processes
Authors: Sølling Theis I. , Møller Klaus B.
Published: December 2018

Coherence is one of the most important phenomena in ultrafast sciences. We give our perspective on the terminology, observation, and preservation of coherence in photophysical processes with some glimpses to the past and some looking-head to what may pave the way for scaling one of the last bastions in ultrafast science, namely, that of mode specific chemistry where it will be possible to break any specific bond by tailoring the pulse, an accomplishment that obviously would be the dream of any chemist.
Detection of nonmagnetic metal thin film using magnetic force microscopy
Authors: Wakaya Fujio , Oosawa Kenta , Kajiwara Masahiro , Abo Satoshi , Takai Mikio
Published: December 2018

Magnetic force microscopy (MFM) allows detection of stray magnetic fields around magnetic materials and the two-dimensional visualization of these fields. This paper presents a theoretical analysis of the oscillations of an MFM tip above a thin film of nonmagnetic metal. The results show good agreement with experimental data obtained by varying the tip height. The phenomenon analyzed here can be applied as a “metal detector” at the nanometer scale and for contactless measurements of sheet resistivity. The detection sensitivity is obtained as a function of oscillation frequency, thus allowing the determination of the best frequency for the phase-shift measurement. The shift in resonance frequency due to the presence of a nonmagnetic metal is also discussed.
Probing the importance of ECM alignment on cell migration
Authors: Bardi Jason Socrates
Published: December 2018

Screening for the influence of size, density and alignment of ECM fibrils in fibrous tissues shows that highly aligned adhesions are correlated with rapid migration.
Variable past-time expression across multiple tasks in Tucumán, Argentina
Authors: Terán Virginia , Kanwit Matthew
Published: December 2018

We examine variable past-time expression in urban Tucumán, Argentina, an understudied region representative of the set of Andean varieties included in Northwestern Argentinean Spanish. We analyze the present perfect (PP) and preterit in two contexts of data collection: a sociolinguistic interview and a contextualized preference task across a range of linguistic and social factors, such as temporal reference and speaker age. Oral results indicate that Tucumán has a higher frequency of use of the PP than has yet been documented in Latin American varieties and even Peninsular Spanish, previously argued to have the highest rate. Preference task results yielded somewhat lower PP rates, confirming that the PP is preferred in speech, whereas the preterit is more viable in written language. The current study documents the highest rate of use of the PP to date across a number of linguistic contexts, contributing to our knowledge of the processes of grammaticalization and task-related differences.
A cytogenetic analysis of male meiosis inAsparagus officinalis
Authors: Yuan Jinhong , Yuan Jiaojiao , Zhou Huihui , Su Qiaoqiao , Ji Shuai , Li Yuqing , Guo Siyi , Li Junhua
Published: December 2018

Asparagus (Asparagus officinalis) has several traits that make it a useful model for cytogenetic studies, however, few studies of the meiosis process have been made in asparagus. Here, we present in detail an atlas of male meiosis in asparagus, from preleptotene to telophase II. The meiosis process in asparagus is largely similar to those of the well-characterized model plants Arabidopsis thaliana, Zea mays, and Oryza sativa. However, most asparagus prophase I meiotic chromosomes show a strongly aggregated morphology, and this phenotype persists through the pachytene stage, highlighting a property in the control of chromosome migration and distribution in asparagus. Further, we observed no obvious banding of autofluorescent dots between divided nuclei of asparagus meiocytes, as one would expect in Arabidopsis. This description of wild-type asparagus meiosis will serve as a reference for the analyses of meiotic mutants, as well as for comparative studies among difference species.

Abbreviations: DAPI: 4’,6-diamidino-2-phenylindole; FISH: fluorescence in situ hybridization; PBS: phosphate-buffered saline; PMC: pollen mother cell; SEM: Scanning Electron Microscope
Production of prostaglandin F2α by molecular breeding of an oleaginous fungus Mortierella alpina
Authors: Farida Asras Mohd Fazli , Shimada Yoshimi , Nagano Hideaki , Munesato Kei , Takeuchi Michiki , Takemura Miho , Ando Akinori , Ogawa Jun
Published: December 2018

Cyclooxygenases are responsible for the production of prostaglandin H2 (PGH2) from arachidonic acid. PGH2 can be converted into some bioactive prostaglandins, including prostaglandin F2α (PGF2α), a potent chemical messenger used as a biological regulator in the fields of obstetrics and gynecology. The chemical messenger PGF2α has been industrially produced by chemical synthesis. To develop a biotechnological process, in which PGF2α can be produced by a microorganism, we transformed an oleaginous fungus, Mortierella alpina 1S-4, rich in triacylglycerol consisting of arachidonic acid using a cyclooxygenase gene from a red alga, Gracilaria vermiculophylla. PGF2α was accumulated not only in the mycelia of the transformants but also in the extracellular medium. After 12 days of cultivation approximately 860 ng/g and 6421 µg/L of PGF2α were accumulated in mycelia and the extracellular medium, respectively. The results could facilitate the development of novel fermentative methods for the production of prostanoids using an oleaginous fungus.
ER-to-Golgi trafficking of procollagen in the absence of large carriers
Authors: McCaughey Janine , Stevenson Nicola L. , Cross Stephen , Stephens David J.
Published: December 2018

Secretion and assembly of collagen are fundamental to the function of the extracellular matrix. Defects in the assembly of a collagen matrix lead to pathologies including fibrosis and osteogenesis imperfecta. Owing to the size of fibril-forming procollagen molecules it is assumed that they are transported from the endoplasmic reticulum to the Golgi in specialized large COPII-dependent carriers. Here, analyzing endogenous procollagen and a new engineered GFP-tagged form, we show that transport to the Golgi occurs in the absence of large (>350 nm) carriers. Large GFP-positive structures were observed occasionally, but these were nondynamic, are not COPII positive, and are labeled with markers of the ER. We propose a short-loop model of COPII-dependent ER-to-Golgi traffic that, while consistent with models of ERGIC-dependent expansion of COPII carriers, does not invoke long-range trafficking of large vesicular structures. Our findings provide an important insight into the process of procollagen trafficking and reveal a short-loop pathway from the ER to the Golgi, without the use of large carriers.
Gustavo Silva: Translating the ubiquitin code
Authors: O’Donnell Marie Anne
Published: December 2018

Silva investigates how ribosomal protein complexes are regulated by K63 ubiquitination.
Toward a better understanding of folate metabolism in health and disease
Authors: Zheng Yuxiang , Cantley Lewis C.
Published: December 2018

Folate metabolism is crucial for many biochemical processes, including purine and thymidine monophosphate (dTMP) biosynthesis, mitochondrial protein translation, and methionine regeneration. These biochemical processes in turn support critical cellular functions such as cell proliferation, mitochondrial respiration, and epigenetic regulation. Not surprisingly, abnormal folate metabolism has been causally linked with a myriad of diseases. In this review, we provide a historical perspective, delve into folate chemistry that is often overlooked, and point out various missing links and underdeveloped areas in folate metabolism for future exploration.
Repeatable Battery for the Assessment of Neuropsychological Status (RBANS): Normative Data for Older Adults
Authors: Olaithe Michelle , Weinborn Michael , Lowndes Talitha , Ng Amanda , Hodgson Erica , Fine Lara , Parker Denise , Pushpanathan Maria , Bayliss Donna , Anderson Mike , Bucks Romola S
Published: December 2018

Objective

Provide updated older adult (ages 60+) normative data for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Form A, using regression techniques, and corrected for education, age, and gender.

Method

Participants (aged 60–93 years; N = 415) were recruited through the Healthy Ageing Research Program (HARP), University of Western Australia, and completed Form A of the RBANS as part of a wider neuropsychological test battery. Regression-based techniques were used to generate normative data rather than means-based methods. This methodology allows for the control of demographic variables using continuous data. To develop norms, the data were assessed for: (1) normality; (2) associations between each subtest score and age, education, and gender; (3) the effect of age, education, and gender on subtest scores; and (4) residual scores which were converted to percentile distributions.

Results

Differences were noted between the three samples, some of which were small and may not represent a clinically meaningful difference. Younger age, more years of education, and female gender were associated with better scores on most subtests. Frequency distributions, means, and standard deviations were produced using unstandardized residual scores to remove the effects of age, education, and gender.

Conclusions

These normative data expand upon past work by using regression-based techniques to generate norms, presenting percentiles, as well as means and standard deviations, correcting for the effect of gender, and providing a free-to-use Excel macro to calculate percentiles.
Towards a better diagnosis and treatment of Rett syndrome: a model synaptic disorder
Authors: Banerjee Abhishek , Miller Meghan T , Li Keji , Sur Mriganka , Kaufmann Walter E
Published: December 2018

Fifty years after the first publication on Rett syndrome, Banerjee et al. review the molecular, cellular and circuit neurobiology of the disorder. They summarize recent advances in therapeutic interventions explored in preclinical models, as well as lessons learnt from past clinical trials and how these might inform future therapeutic approaches.
Can snakes use yolk reserves to maximize body size at hatching?
Authors: Qu Yan-Fu , Zhao Shu-Zhan , Jiang Xu-Fei , Lin Long-Hui , Ji Xiang
Published: December 2018

We experimentally miniaturized freshly laid eggs of the Chinese cobra Naja atra (Elapidae) by removing ∼10% and ∼20% of original yolk. We tested if yolk-reduced eggs would produce 1) normal-sized hatchlings with invariant yolk-free body mass (and thus invariant linear size) but dramatically reduced or even completely depleted residual yolk, 2) smaller hatchlings with normal-sized residual yolk but reduced yolk-free body mass, or 3) smaller hatchlings of which both yolk-free body mass and residual yolk are proportionally reduced. Yolk quantity affected hatchling linear size (both snout-vent length and tail length) and body mass. However, changes in yolk quantity did not affect incubation length or any hatchling trait examined after accounting for egg mass at laying (for control and sham-manipulated eggs) or after yolk removal (for manipulated eggs). Specifically, yolk-reduced eggs produced hatchlings of which all major components (carcass, residual yolk, and fat bodies) were scaled down proportionally. We show that snakes cannot use yolk reserves to maximize their body size at hatching. Furthermore, our data also suggest that the partitioning of yolk in embryonic snakes is species-specific.
Residual left ventricular hypertrophy with adverse clinical outcomes in patients with severe aortic stenosis and asymmetric septal hypertrophy after aortic valve replacement
Authors: Xu Haitao , Duan Yabing , Yuan Xin , Wu Hengchao , Song Yunhu , Xu Jianping , Sun Hansong
Published: December 2018

OBJECTIVES

The aim of this study is to describe the temporal pattern of left atrial (LA) and left ventricular (LV) reverse remodelling and to evaluate the impact of residual LV hypertrophy on the prognosis of patients with severe aortic stenosis and asymmetric septal hypertrophy undergoing aortic valve replacement (AVR).

METHODS

We retrospectively reviewed 59 consecutive patients who underwent AVR for severe aortic stenosis and asymmetric septal hypertrophy. They were divided into the normal LV mass group and the residual LV hypertrophy group according to the LV mass index (LVMI) 2 years after AVR. Thirty patients were eligible for analysis of the time-dependent changes in LA and LV reverse remodelling.

RESULTS

The interventricular septal thickness and LVMI gradually decreased and reached their lowest points 2 years after operation, whereas the LA dimension rapidly decreased in the early postoperative period and plateaued at 3 months. The multivariable analysis revealed a higher preoperative LVMI [odds ratio 6.36 (1.678–24.11); P = 0.007] as an independent predictor of residual hypertrophy 2 years after operation. The Cox proportional hazards model showed that a higher postoperative peak velocity [hazard ratio 6.715 (1.405–32.104); P = 0.017] was an independent predictor of long-term non-fatal cardiovascular hospitalization. Patients with residual hypertrophy 2 years after AVR had a higher rate of non-fatal cardiovascular hospitalization (P = 0.014).

CONCLUSIONS

For patients with severe aortic stenosis and asymmetric septal hypertrophy, maximum LA recovery occurred 3 months after AVR, whereas maximum LV recovery occurred 2 years thereafter. A higher preoperative LVMI may lead to postoperative residual hypertrophy, which is associated with adverse clinical outcomes.
Prominin-like Regulates Longevity and Glucose Metabolism via Insulin Signaling in Drosophila
Authors: Ryu Tae Hoon , Yeom Eunbyul , Subramanian Manivannan , Lee Kyu-Sun , Yu Kweon
Published: December 2018

CD133, also called Prominin-1, is a biomarker for mammalian stem cells. It is involved in cell growth, development, and tumor biology. However, the function of CD133 at the organismal level has not been investigated. In this study, we found that prominin-like (promL) loss-of-function mutant flies show an extended life span and metabolic defects such as increased circulating carbohydrates, lipid storage, and starvation resistance. The messenger RNA expression levels of Drosophila insulin-like peptides (Dilps) were reduced in loss-of-function promL mutants. Furthermore, the level of phosphorylated AKT, a downstream component of insulin signaling, was lower in promL loss-of-function mutants than in the w− control flies. Importantly, the PromL protein is predominantly expressed in the pars intercerebralis region with insulin-producing cells of the adult brain. When we inhibited promL in insulin-producing cells, these flies showed an extended life span, metabolic defects, and reduced insulin signaling. These results indicate that the promL gene regulates longevity and glucose metabolism by controlling insulin signaling in Drosophila.
Reproductions of super-orbital X-ray light-curves with the precessing accretion ring model and implications on accretion flows through accretion rings
Authors: Inoue Hajime
Published: December 2018

X-ray light-curves of three X-ray pulsars, SMC X-1, LMC X-4, and Her X-1, folded with their respective super-orbital periods, are shown to be well reproduced by a model in which X-rays from a compact object towards us are periodically obscured by a precessing ring at the outermost part of an accretion disk around the central object. A situation is considered in which matter from a companion star flows into a gravitational field of a compact star carrying a certain amount of specific angular momentum and first forms a geometrically thick ring-tube along the Keplerian circular orbit. For the model to well fit to the observations, it is necessary that the optical depth of the ring-tube for Compton scattering, τ ≃ 1 ∼ 2, the ring matter temperature, T ≃ 105 ∼ 106 K, and the ionization parameter, ξ ≃ 102 erg cm s−1 due to X-ray heating from the central X-ray source.From simple energetics- and perturbation-arguments, we find that a precession of such a ring is rather stable and can be excited in the T and ξ ranges. The time during which matter accumulates in the ring is estimated to be ∼106 s, and is shown to be comparable to the time for an accretion disk to extend from the ring. It is discussed that in the above T and ξ ranges, the ring-tube matter could become thermally unstable. Then, relatively high density regions in the ring-tube further cool down and tend to shrink to the tube center. The flow across the ring circulating flow should excite turbulent motions, and angular momenta of the matter would be effectively transferred across the tube. Finally, a steady flow should be established from the companion star through the accretion ring to the accretion disk towards the central compact star.
Evidence on factors influencing contraceptive use and sexual behavior in South Africa
Authors: Hlongwa Mbuzeleni , Mashamba-Thompson Tivani , Hlongwana Khumbulani
Published: December 2018

Background:

Contraceptive use and sexual health behavior remain a prominent public health concern in South Africa. Despite many government interventions, unplanned pregnancies, number of abortions, and maternal mortality remain relatively high. Due to high pregnancy levels and the stigma associated with termination of pregnancy, more women turn to unsafe and illegal abortions despite the risks involved. Risky sexual behavior pose a serious risk of contracting HIV/AIDS. The main objective of this study is to map evidence on factors influencing contraceptive use and sexual behavior in South Africa.

Methods:

We will conduct a scoping review guided by framework by Arksey and O’Malley. This study will search for eligible literature from peer-reviewed articles and grey literature. Databases such as PubMed/MEDLINE, American Doctoral Dissertations via EBSCO host, Union Catalogue of Theses and Dissertations (UCTD) and SA ePublications via SABINET Online and World Cat Dissertations, Theses via OCLC, and Google Scholar will be searched. Websites such as the World Health Organization (WHO) and governmental websites and statistics institutions will be explored for policies and guidelines on contraceptive use and sexual behavior. The review will be conducted on studies that were published from January 1990 to 2018. The PCC framework will be employed in this study to determine the eligibility of research question. The PRISMA chart will be utilized to report the screening of results. The MMAT Tool version 11 will be used to determine the quality of the included primary studies.

Results:

We anticipate finding a considerable number of published articles presenting evidence on contraceptive use and sexual health behavior in South Africa. Findings of this scoping review will be disseminated electronically, in print, and through peer presentation, conferences, and congresses.
Association between indication for therapy by nutrition support team and nutritional status
Authors: Shin Byung Chul , Chun In Ae , Ryu So Yeon , Oh Ji Eun , Choi Pahn Kyu , Kang Hyun Goo
Published: December 2018

The nutrition support team is a multidisciplinary team composed of medical doctors, registered nurses, pharmacists, and nutritionists, who evaluate the nutritional status of patients. The objective of this study was to determine the relationship between indications for nutrition support team therapy and the nutritional status of patients hospitalized in local major hospitals.

Patients who were referred to a nutrition support team from January to December 2016 were enrolled. Patients were classified into 4 age groups, and the weight categories were determined using body mass index (BMI). Four of 6 indications were used for referral to a nutrition support team. The required calories were estimated, and the nutritional status was classified into malnutrition or eutrophia, based on the estimation.

The proportion of elderly patients (37.0%) was higher than that of younger ones (28.3%). Patients with higher BMI had a relatively lower proportion of malnutrition. Patients receiving enteral nutrition had greater risk of malnutrition (adjusted odds ratio [aOR] = 3.77, 95% confidence interval [CI] = 2.71–5.24). Patients receiving parenteral nutrition (aOR = 0.38, 95% CI = 0.30–0.47) and treated in the intensive care unit (aOR = 0.70, 95% CI = 0.54–0.91) had lower risk of malnutrition. Patients with >3 indications for nutrition support team therapy had a lower risk of malnutrition than those with only 1 indication (aOR = 0.54, 95% CI = 0.37–0.77).

Parenteral nutrition was the most common indication for referral to nutrition support team therapy; however, enteral nutrition had the poorest nutritional status. Patients receiving enteral nutrition who are referred to a nutrition support team need an intensive nutrition support strategy.
Herbal medicine (zhishi xiebai guizhi decoction) for unstable angina
Authors: Tang Yong , Cai Hairong , Zhan Zhenye , Luo Yajie , Huang Yonglian , Chen Dongjie , Chen Bojun
Published: December 2018

Background:

Unstable angina (UA) is a clinically common coronary heart disease. Zhishi xiebai guizhi decoction (ZXGD) has been widely used in the management of UA, although its effective evidence is not clear and there is no systematic review regarding its efficacy and safety. Therefore, we conduct this systematic review protocol to evaluate the efficacy and safety of ZXGD in the treatment of UA.

Methods:

We will search the following electronic databases: Cochrane Library, Web of Science, PubMed, EBASE, Springer, WHO International Clinical Trial Registration Platform, China Biomedical Literature Database, China National Knowledge Infrastructure, Chinese Scientific Journal Database (VIP), and Wan-fang database from their inception to October 2018. Only randomized controlled trials (RCTs) published in English and Chinese will be included. Continuous data will be expressed as mean difference or standard mean difference, and dichotomous data relative as risk. Study selection, data extraction, and assessment with risk of bias and data analysis will be performed by two independent authors. RevMan software version 5.3 will be used for meta-analysis.

Results:

This study will provide high-quality evidence of ZXGD in the treatment of UA from the following aspects, including clinical efficacy, blood lipids, Seattle angina scale, electrocardiogram improvement, ST-segment depression, left ventricular ejection fraction, angina duration, and adverse events.

Conclusion:

This systematic review will provide a basis for judging whether ZXGD is an effective intervention for UA or not.

PROSPERO registration number:

PROSPERO CRD 42018115528.
Quality Improvement Initiative Reduces the Occurrence of Complications in Peripherally Inserted Central Catheters
Authors: Walters Beth , Price Chelsey
Published: December 2018

Peripherally inserted central catheters (PICCs) are commonly used to access the central venous system. However, central vascular access devices are associated with a risk of complications, which may include infection, thrombosis, occlusion, or malposition. The vascular access team of 1 midwestern hospital used a quality improvement initiative to reduce the occurrence of complications associated with PICCs. A secondary aim was to reduce the number of alteplase (Cathflo Activase; Genentech, South San Francisco, CA) doses administered. After reviewing current evidence, the vascular access team employed the Plan-Do-Study-Act cycle to document and implement changes in practice. By using a team initiative to investigate this issue, complication rates decreased and patient satisfaction improved. The thrombosis rate decreased by 67%, occlusions by 75%, and alteplase use by 87%. No infections occurred during this study.