bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure evolution of blast furnace slag with high Al2O3 Content and 5 mass% TiO2 via molecular dynamics simulation and fourier transform infrared spectroscopy
Authors: Yuelin Qin , Hao Liu , Yanhua Yang
Published: November 2017

The structure of a quenched blast furnace slag containing 5 mass% TiO2 was investigated via molecular dynamics simulation and Fourier transform infrared spectroscopy. The simulation and experimental results obtained revealed that the slag possesses a depolymerized network of [SiO4] and [AlO4] tetrahedra. At a fixed CaO/SiO2 mass fraction of 1.17 and 12 mass% Al2O3, increasing the amount of MgO decreased the bridging oxygen fraction in the slag system, thus resulting in silicate depolymerization. At a fixed CaO/SiO2 mass fraction of 1.17 and 8 mass% MgO, increasing Al2O3 content increased the bridging oxygen fraction because of the polymerization of aluminate structures. At a fixed 8 mass% MgO and 12 mass% Al2O3, increasing the CaO/SiO2 mass fraction from 1.07 to 1.50 decreased the bridging oxygen fraction because of the depolymerization of silicate and aluminate structures. Analyzing the slag structure via FT-IR spectroscopy verified these behaviors.
Allyl and 2-Cyclopropylethyl Rearrangements in the Reaction of 1-Alkenylaluminums with Diiodomethane/Triethylaluminum Reagent
Authors: Ramazanov Ilfir , Yaroslavova Alsu , Yaubasarov Niyaz , Dzhemilev Usein
Published: November 2017

The reaction of diiodomethane and triethylaluminum with substituted 1-alkenylaluminums obtained by the Zr-catalyzed carbo- or cycloalumination of mono- or dialkyl-substituted alkynes resulted in the selective formation of di- and tetrasubstituted cyclopropanes. 1-Alkenylaluminums prepared from substituted propargylamines reacted with diiodomethane and triethylaluminum to give substituted allylamines. A plausible mechanism for the reaction of the 1-alkenylaluminums with diiodomethane/triethylaluminum is proposed.
Short Synthesis of the Antidiabetic Octaketide Ethyl 2-(2,3,4-Trimethoxy-6-octanoylphenyl)acetate
Authors: Seo Seung-Yong , Sun Wei , Yuan Yue , Lee Bit , Jun Hee-Sook , Shin Dongyun
Published: November 2017

A facile and practical approach for the synthesis of ethyl 2-(2,3,4-trimethoxy-6-octanoylphenyl)acetate, an antidiabetic octaketide analogue of cytosporone B, is described. Unlike known approaches for the synthesis of cytosporones and their analogues, the key step of the developed route is a Friedel–Crafts alkylation of 1-(3,4,5-trimethoxyphenyl)octan-1-one with ethyl chloro(methylthio)acetate, followed by desulfurization.
Outcomes of Traumatic Pancreatic Injuries in Pediatric and Adult Patients: A Retrospective Study Involving Four Trauma Centers
Authors: Iurcotta Toni , Addison Poppy , Amodu Leo , Akerman Meredith , Rilo Horacio
Published: November 2017

Traumatic injuries of the pancreas are rare and affect both children and adults. Very little has been done to investigate differences in outcome between these two age groups. We performed a retrospective review of cases in four trauma hospitals to determine the differences in outcomes between pediatric and adult patients with traumatic pancreatic injuries. A retrospective chart review was performed for 69 pediatric and adult patients seen at four trauma centers in our health system between 1990 and 2014. The Mann–Whitney's U-test was used to compare continuous variables, while the chi-square and Fisher's exact tests were used for categorical variables. Mortality was determined using the Social Security Death Master File. In this study, 26 pediatric and 43 adult patients were included. Median ages were 11.4 and 42.3 years, respectively. There were significant differences in mechanism of blunt injury between pediatric and adults (motor vehicle collisions = 17.4 vs. 64.9%, bicycle accidents = 43.5 vs. 0.0%; p-value for both comparisons < 0.0001), median injury severity score (6.5 vs. 12; p = 0.030), surgical management (30.8 vs. 67.4%; p = 0.003), and postinjury pancreatitis (57.7 vs. 20.9%; p = 0.002). Median hospital length of stay was 5 versus 11 days (p = 0.005), respectively. There were no differences in mortality or other complications. In spite of significant differences in blunt injury type, injury severity, and the need for surgery, there were no significant differences in mortality or most postinjury complications between pediatric and adult patients with traumatic pancreatic injuries.
Ultrasound-Guided Cannulation of the Brachiocephalic Vein in Neonates and Preterm Infants: A Prospective Observational Study
Authors: Alonso-Quintela Paula , Terroba-Seara Sandra , Jiménez-González Aquilina , Rodríguez-Blanco Silvia , Vázquez-Martínez José , Oulego-Erroz Ignacio
Published: November 2017

Introduction Percutaneous central venous catheter (CVC) insertion is a challenging procedure in neonates, especially in preterm infants.

Objective This study aims to describe the technical success and safety profile of ultrasound (US)-guided brachiocephalic vein (BCV) cannulation in neonates.

Methods Prospective observational study. Neonates admitted to the neonatal intensive care unit (NICU) in whom US-guided cannulation of the BCV was attempted were eligible. Outcomes included first attempt success rate, the overall success rate, the number of attempts, the cannulation time, immediate mechanical complications, catheter indwelling days, and late complications.

Results A total of 40 procedures in 37 patients were included. Median weight and age at the time of cannulation were 1.85 kg (0.76–4.8) and 13 days (3–31), respectively. First attempt and overall success rates were 29 (72.5%) and 38 (95%), respectively. No major complications were observed. Catheter-associated infection rate was 2.4/1,000 catheter days. There were no difference in outcomes between low weight preterm infants (<1.5 kg) and the rest of the cohort. There was no linear relationship between weight at time of insertion and the number of puncture attempts (r = 0.250; p = 0.154) or cannulation time (r = 0.257; p = 0.142).

Conclusion US-guided cannulation of the BCV may be considered in acutely ill neonates, including small preterm infants, who need a large bore CVC.
Neonatal Outcomes Differ after Spontaneous and Indicated Preterm Birth
Authors: Demaree Devyn , Merfeld Emily , Tuuli Methodius , Wambach Jennifer , Cole F. , Cahill Alison , Stout Molly
Published: November 2017

Objective Preterm birth (PTB) at <37 weeks of gestation complicates 10% of pregnancies and requires accurate counseling regarding anticipated neonatal outcomes. PTB classification as spontaneous or indicated is commonly used to cluster PTB into subtypes, but whether neonatal outcomes differ by PTB subtype is unknown. We tested the hypothesis that neonatal morbidity differs based on subtype of PTB.

Methods We performed a retrospective cohort study of live-born, non-anomalous preterm infants from 2004 to 2008. Spontaneous PTB was defined as PTB from spontaneous preterm labor or preterm rupture of membranes. Indicated PTB was defined as PTB from any maternal or fetal medical complication necessitating delivery. The primary outcome was a composite of early respiratory morbidity. Secondary outcomes included late composite respiratory morbidity and other neonatal morbidities.

Results Of 1,223 preterm neonates, 60.9% were born after spontaneous PTB and 30.1% after indicated PTB. Composite early respiratory morbidity was significantly higher after indicated PTB versus spontaneous PTB (1.3, 95% confidence interval [CI] 1.2–1.4). Composite late respiratory morbidity (1.8, 95% CI 1.3–2.3) and neonatal death (2.8, 95% CI 1.5–5.1) were also significantly higher after indicated PTB versus spontaneous PTB.

Conclusion Neonatal respiratory outcomes and death differ according to PTB subtype. PTB subtype should be considered while counseling families and anticipating neonatal outcomes after PTB.
Impact of Intended Mode of Delivery on Outcomes in Preterm Growth-Restricted Fetuses
Authors: Kuper Spencer , Wang Michelle , Steele Robin , Biggio Joseph , Harper Lorie , Baalbaki Sima
Published: November 2017

Background Scheduled cesarean is frequently performed for fetal growth restriction due to concerns for fetal intolerance of labor.

Objective We compared neonatal outcomes in preterm growth-restricted fetuses by intended mode of delivery.

Study Design We performed a retrospective cohort study of indicated preterm births with prenatally diagnosed growth restriction from 2011 to 2014 at a single institution. Patients were classified by intended mode of delivery. The primary outcome was a composite of adverse neonatal outcomes, including perinatal death, cord blood acidemia, chest compressions during neonatal resuscitation, seizures, culture-proven sepsis, necrotizing enterocolitis, and grade III–IV intraventricular hemorrhage. Secondary analysis was performed examining the impact of umbilical artery Dopplers.

Results Of 101 fetuses with growth restriction, 75 underwent planned cesarean deliveries. Of those induced, 46.2% delivered vaginally. Delivery by scheduled cesarean was not associated with a decreased risk of the composite outcome (adjusted odds ratio [aOR], 1.61; 95% confidence interval [CI], 0.45–5.78), even when only those with abnormal umbilical artery Dopplers were considered (aOR, 2.8; 95% CI, 0.40–20.2).

Conclusion In this cohort, planned cesarean was not associated with a reduction in neonatal morbidity, even when considering only those with abnormal umbilical artery Dopplers. In otherwise appropriate candidates for vaginal delivery, fetal growth restriction should not be considered a contraindication to trial of labor.
Does Posterior Condylar Offset Affect Clinical Results following Total Knee Arthroplasty?
Authors: Degen Ryan , Matz Jacob , Teeter Matthew , Lanting Brent , Howard James , McCalden Richard
Published: November 2017

Total knee arthroplasty (TKA) is an effective, durable treatment for knee osteoarthritis. However, a subset of patients experiences incomplete pain relief and ongoing dysfunction. Posterior condylar offset (PCO) has previously been shown to be associated with postoperative range of motion (ROM) following TKA; however, an association with patient-reported outcome measures (PROMs) has not been established. The purpose of this study was to evaluate the association between PCO and postoperative ROM and PROMs. A retrospective review of 970 posterior-stabilized single design TKAs was performed. Preoperative and postoperative radiographs were analyzed to measure the change in PCO and anteroposterior (AP) femoral dimension. Clinical outcome measures, including Short Form-12 physical and mental component summaries, Western Ontario and McMaster Universities Arthritis Index, and Knee Society Score were reviewed to determine if these were influenced by changes in PCO and AP dimension. PCO was increased by more than 3 mm in 15.1%, maintained (within 3 mm) in 59.6%, and decreased by more than 3 mm in 25.3% of patients. Comparing between these groups, there were no significant differences in postoperative ROM or PROM. AP dimension increased in 24.4%, maintained in 47.8%, and decreased in 27.8%. Similarly, there were no significant differences in ROM or PROM between these groups. Spearman's correlation analyses failed to identify an association between PCO and ROM or PROMs. In conclusion, increasing or decreasing PCO or AP femoral dimension with this PS TKA design did not significantly affect postoperative ROM or PROM. Similarly, maintenance of PCO within one implant size with this system compared with optimal sizing had no deleterious effect on TKA outcomes.
Systematic Review of the Epidemiology and Natural History of the Metabolic Vascular Syndrome and its Coincidence with Type 2 Diabetes Mellitus and Cardiovascular Diseases in Different European Countries
Authors: Kwasny Caroline , Manuwald Ulf , Kugler Joachim , Rothe Ulrike
Published: November 2017

The objectives of this systematic review were to estimate the incidence, prevalence and natural history of the metabolic (vascular) syndrome (MVS) among adults in different European countries. Furthermore, we assessed its co-incidence with type 2 diabetes (T2DM) and cardiovascular diseases (CVD). PubMed, MedLine, and EMBASE (via Ovid) were searched for relevant studies. After reading 116 full-text articles to find eligible ones, 66 publications met our inclusion criteria. Data for the incidence are based on a study from Portugal, in which the incidence rate for the MVS was 47.2/1000 person-years. Prevalence varied strongly depending on country and definition. The lowest was found in the United Kingdom (3%), the highest in Finland (71.7%). No article that deals with the natural history of the MVS was found. Considering the co-existence of MVS and T2DM, it ranged between 2% (United Kingdom) and 74.4% (Spain). The co-occurrence of MVS and CVD ranged from 2.8% (Italy) up to 52% (Netherlands). Coronary heart disease (CHD) varied between 1.2% and 44.2%. With regard to peripheral artery disease (PAD), values between 3.3% and 59.8% were found. Due to the many different definitions of the MVS, a comparison is very difficult. Overall prevalence ranged between 3% and 71.7% depending on definition, age, and country. An association between MVS and T2DM as well as several CVD can be assumed.
Angle and rotational direction dependent horizontal loop shift in epitaxial Co/CoO bilayers on MgO(100)
Authors: Ehrmann Andrea , Blachowicz Tomasz
Published: November 2017

Co/CoO belongs to the typical exchange bias systems which have been investigated for decades. Surprisingly, Co/CoO thin film systems epitaxially grown on MgO(100) substrates show a strong influence of the relative orientation of the average uncompensated antiferromagnetic magnetization with respect to the cooling field direction, giving rise to unexpected asymmetric angular dependencies of the horizontal loop shift as well as the sign of the transverse magnetization peaks in magneto-optical Kerr effect (MOKE) experiments. In this paper, we provide a broad overview of the influence of cooling field orientation and sample orientation on magnetization reversal processes in this system.
Stable azodye photo-alignment layer for liquid crystal devices achieved by “turning off” dye photosensitivity
Authors: McGinty C. , Finnemeyer V. , Reich R. , Clark H. , Berry S. , Bos P.
Published: November 2017

We have previously proposed a low cost, versatile process for stabilizing azodye photo-alignment layers for liquid crystal devices by utilizing a surface localized reactive mesogen (RM) layer. The RM is applied by dissolving the monomer in a liquid crystal material prior to filling the cell. In this paper, we show the significant effect of azodye layer thickness on the long term stability of these alignment layers when exposed to polarized light. We demonstrate, surprisingly, that thin azodye layers (∼3 nm) provide improved stability over thicker (∼40 nm) layers. Using this process, we show cells which have been stable to exposure with polarized light through one month. Additionally, we demonstrate the use of a photo-alignment layer to align the liquid crystals that afterwards can be rendered insensitive to polarized light. This was accomplished by using the process described above with the additional step of eliminating the photosensitivity of the azodye layer through photo-bleaching; the result is an RM alignment layer that will be stable when exposed to polarized light in the dye absorption band.
Anisotropic percolation conduction in elastomer-carbon black composites investigated by polarization-sensitive terahertz time-domain spectroscopy
Authors: Okano Makoto , Fujii Misako , Watanabe Shinichi
Published: November 2017

We investigated the draw ratio (DR) dependence of the anisotropic dielectric function and conductivity of styrene butadiene rubbers (SBRs) with different carbon black (CB) concentrations by polarization-sensitive terahertz time-domain spectroscopy. From the frequency dependence of the conductivity in the unstretched SBRs ranging from direct current to terahertz frequencies, it is found that the SBR with a CB concentration above 30 wt. % exhibits percolation conductivity. We investigated the spectral shape of the dielectric function and conductivity of the SBR samples below and above the percolation threshold for two representative DRs in the terahertz frequency region. We found that the DR dependence of the spectral shape is well explained by the effective medium approximation, except for the sample with the CB concentration above 30 wt. % under the unstretched condition. The conductivity in that sample remarkably changes in the low terahertz frequency region, which suggests a change in the CB network by deformation. The investigation of the dielectric anisotropy and percolation conductivity using our polarization technique can be applied to a wide range of elastomer composites.
Anomalous Nernst effect in Ir22Mn78/Co20Fe60B20/MgO layers with perpendicular magnetic anisotropy
Authors: Tu Sa , Hu Junfeng , Yu Guoqiang , Yu Haiming , Liu Chuanpu , Heimbach Florian , Wang Xiangrong , Zhang Jianyu , Zhang Youguang , Hamzić Amir , Wang Kang L. , Zhao Weisheng , Ansermet Jean-Philippe
Published: November 2017

The anomalous Nernst effect in a perpendicularly magnetized Ir22Mn78/Co20Fe60B20/MgO thin film is measured using well-defined in-plane temperature gradients. The anomalous Nernst coefficient reaches 1.8 μV/K at room temperature, which is almost 50 times larger than that of a Ta/Co20Fe60B20/MgO thin film with perpendicular magnetic anisotropy. The anomalous Nernst and anomalous Hall results in different sample structures revealing that the large Nernst coefficient of the Ir22Mn78/Co20Fe60B20/MgO thin film is related to the interface between CoFeB and IrMn.
Triggering breakdown voltage of a high-current, two-electrode graphite gas switch assisted by ultraviolet pre-ionization
Authors: Chen Li , Yang Lanjun , Huang Dong , Liu Shuai , Lin Tianyu
Published: November 2017

A simple ultraviolet pre-ionization device designed to extend the lifetime of a high current, two-electrode graphite gas switch is described in this paper. The effects of UV-illumination on decreasing the triggering breakdown voltage were studied in theory and experiments. The results showed that UV-illumination can provide extra initial electrons on the cathode surface and make more air molecules in the excited state, which resulted in positive effects in reducing the triggering breakdown voltage and jitter. However, the effects became weak as the pressure increased; the reason of this phenomenon was that the ultraviolet absorption rate of the air molecules increased with the rising pressure, leading to a reduction of the ultraviolet intensity on the discharge gap. The largest value of the triggering breakdown voltage decreased was 13.5 kV under 100 kPa, and the reliable operation gap distance can extend another 1.2 mm, which was equivalent to 500 shots in our experiments.
Study of hydrogen-molecule guests in type II clathrate hydrates using a force-matched potential model parameterised from ab initio molecular dynamics
Authors: Burnham Christian J. , Futera Zdenek , English Niall J.
Published: November 2017

The force-matching method has been applied to parameterise an empirical potential model for water-water and water-hydrogen intermolecular interactions for use in clathrate-hydrate simulations containing hydrogen guest molecules. The underlying reference simulations constituted ab initio molecular dynamics (AIMD) of clathrate hydrates with various occupations of hydrogen-molecule guests. It is shown that the resultant model is able to reproduce AIMD-derived free-energy curves for the movement of a tagged hydrogen molecule between the water cages that make up the clathrate, thus giving us confidence in the model. Furthermore, with the aid of an umbrella-sampling algorithm, we calculate barrier heights for the force-matched model, yielding the free-energy barrier for a tagged molecule to move between cages. The barrier heights are reasonably large, being on the order of 30 kJ/mol, and are consistent with our previous studies with empirical models [C. J. Burnham and N. J. English, J. Phys. Chem. C 120, 16561 (2016) and C. J. Burnham et al., Phys. Chem. Chem. Phys. 19, 717 (2017)]. Our results are in opposition to the literature, which claims that this system may have very low barrier heights. We also compare results to that using the more ad hoc empirical model of Alavi et al. [J. Chem. Phys. 123, 024507 (2005)] and find that this model does very well when judged against the force-matched and ab initio simulation data.
Prediction of optically-active transitions in type-VIII guest-free silicon clathrate Si46: A comparative study of its physical properties with type-I counterpart through first-principles
Authors: Mahammedi Nassim Ahmed , Ferhat Marhoun , Tsumuraya Takao , Chikyow Toyohiro
Published: November 2017

We have systematically studied the structural, electronic, and optical properties of two types of guest-free Si46 silicon clathrates using first-principles density-functional theory calculations. The properties are compared between two different crystal structures with the same chemical formula of Si46, type-I, and type-VIII. We apply a hybrid functional approach with the Becke, Lee-Yang-Parr (BLYP) functional and compare the electronic properties with those by generalized gradient approximation (GGA-PBE). The band structures of both clathrates calculated within the GGA indicate semiconducting (insulating) properties with indirect bandgaps of 1.38 and 1.36 eV for type-I and type-VIII, respectively. These band gaps increase to 1.60 and 1.62 eV by using the BLYP hybrid functional. The calculated optical absorption of type-I clathrate is slightly larger than that of type-VIII. Lastly, we also performed a symmetry analysis of optical transitions for both Si46 clathrates. It is found that optical transitions are dipole-allowed at the band-edge located along the Γ–Η line for Si46-VIII, while the transitions for type-I Si46 are forbidden by symmetry. It is hoped that this finding will motivate further investigations of optical capabilities of the silicon based type-VIII clathrates for photovoltaic and photonic devices.
Light-erasable embedded charge-trapping memory based on MoS2 for system-on-panel applications
Authors: He Long-Fei , Zhu Hao , Xu Jing , Liu Hao , Nie Xin-Ran , Chen Lin , Sun Qing-Qing , Xia Yang , Wei Zhang David
Published: November 2017

The continuous scaling and challenges in device integrations in modern portable electronic products have aroused many scientific interests, and a great deal of effort has been made in seeking solutions towards a more microminiaturized package assembled with smaller and more powerful components. In this study, an embedded light-erasable charge-trapping memory with a high-k dielectric stack (Al2O3/HfO2/Al2O3) and an atomically thin MoS2 channel has been fabricated and fully characterized. The memory exhibits a sufficient memory window, fast programming and erasing (P/E) speed, and high On/Off current ratio up to 107. Less than 25% memory window degradation is observed after projected 10-year retention, and the device functions perfectly after 8000 P/E operation cycles. Furthermore, the programmed device can be fully erased by incident light without electrical assistance. Such excellent memory performance originates from the intrinsic properties of two-dimensional (2D) MoS2 and the engineered back-gate dielectric stack. Our integration of 2D semiconductors in the infrastructure of light-erasable charge-trapping memory is very promising for future system-on-panel applications like storage of metadata and flexible imaging arrays.
Superbanana transport in the collisional heating of a plasma column forced across a squeeze potential
Authors: Dubin Daniel H. E.
Published: November 2017

When weakly collisional plasmas have locally trapped particle populations, perturbations to the plasma equilibrium (such as waves or static field-errors) can induce phase-space discontinuities in the particle distribution function that strongly enhance entropy production, plasma loss, and wave damping via superbanana transport. This paper presents a simple version of this superbanana transport process, wherein a plasma is heated as it is slowly forced back and forth across a squeeze potential (at a frequency ω that is small compared with the particle bounce frequency). The squeeze potential traps low-energy particles on either side of the squeeze, but particles with higher energy can pass through it. Trapped and passing particles have different responses to the forcing, causing a collisionless discontinuity in the distribution function at the separatrix between the trapped and passing particles. Expressions for both the adiabatic and non-adiabatic distribution functions are presented, and the heating rate caused by collisional broadening of the separatrix discontinuity is derived. The heating rate is proportional to νω, provided that ν≪ω, where ν is the collision rate (i.e., the ν regime of superbanana theory).
Competition-free second harmonic mode THz orbital angular momentum gyrotron with dual-mode operation by a perturbed cavity
Authors: Sawant A. , Choi E. M.
Published: November 2017

We propose a dual-mode orbital angular momentum (OAM) scheme at 400 GHz that uses a gyrotron. A conventional gyrotron with two modes of operation has a second harmonic resonance that competes with the fundamental mode. We used a perturbed cavity to reduce the fundamental mode competition in a second harmonic gyrotron by allowing higher-order axial mode operation. Based on a simulation using an in-house self-consistent gyrotron code, we demonstrated that the operating dual second harmonic modes TE6,4(+)/TE12,2(+) of the OAM source in the perturbed cavity at around 400 GHz can be excited without competition from the fundamental mode TE4,2(−).
Pure radiation in space-time models that admit integration of the eikonal equation by the separation of variables method
Authors: Osetrin Evgeny , Osetrin Konstantin
Published: November 2017

We consider space-time models with pure radiation, which admit integration of the eikonal equation by the method of separation of variables. For all types of these models, the equations of the energy-momentum conservation law are integrated. The resulting form of metric, energy density, and wave vectors of radiation as functions of metric for all types of spaces under consideration is presented. The solutions obtained can be used for any metric theories of gravitation.
Effects of partial substitution of cations on electrical properties of Mn-Co-Ni-O thin films
Authors: Zhang Fei , Huang ZhiMing
Published: November 2017

Mn-Co-Ni-O thin films have important usage values, and their extensive applications require further improvement of the electrical properties. The cations of Mn-Co-Ni-O thin films were partially substituted by Sb, Rh, Sc, and Cu elements individually, and the Cu-incorporated thin film was found to have the best electrical property to be applicable. In order to improve the anti-aging property of the Cu-incorporated thin film, the Sc element was added into it, which effectively slowed down the aging rate, and the mechanisms were explained. According to the analysis of XPS spectra, it was found that the conduction mechanism was still the electron hopping conductance between Mn3+ and Mn4+ ions after the additional substitution of Cu or Cu/Sc elements in Mn-Co-Ni-O thin films. The Raman spectral analysis indicated that the incorporated Sc element was mainly Sc3+ ions distributed in the octahedron. However, the incorporated Cu element was mainly Cu1+ ions distributed in the tetrahedron.
Effects of various conditions in cold-welding of copper nanowires: A molecular dynamics study
Authors: Zhou Hongjian , Wu Wen-ping , Wu Runni , Hu Guoming , Xia Re
Published: November 2017

Cold-welding possesses such desirable environment as low temperature and low applied stress, thus becoming the prime candidate for nanojointing and nanoassembly techniques. To explore the welding mechanism of nanoscale structures, here, molecular dynamics was performed on copper nanowires under different welding conditions and various original characteristics to obtain an atomic-level depiction of their cold-welding behavior. By analyzing the mechanical properties of as-welded nanowires, the relations between welding quality and welding variables are revealed and identified. This comparison study will be of great importance to future mechanical processing and structural assembly of metallic nanowires.
Electron parallel transport for arbitrary collisionality
Authors: Ji Jeong-Young , Yun Gunsu S. , Na Yong-Su , Held Eric D.
Published: November 2017

Integral (nonlocal) closures [J.-Y. Ji and E. D. Held, Phys. Plasmas 21, 122116 (2014)] are combined with the momentum balance equation to derive electron parallel transport relations. For a single harmonic fluctuation, the relations take the same form as the classical Spitzer theory (with possible additional terms): The electric current and heat flux densities are connected to the modified electric field and temperature gradient by transport coefficients. In contrast to the classical theory, the dimensionless coefficients depend on the collisionality quantified by a Knudsen number, the ratio of the collision length to the angular wavelength. The key difference comes from the proper treatment of the viscosity and friction terms in the momentum balance equation, accurately reflecting the free streaming and collision terms in the kinetic equation. For an arbitrary fluctuation, the transport relations may be expressed by a Fourier series or transform. For low collisionality, the electric resistivity can be significantly larger than that of classical theory and may predict the correct timescale for fast magnetic reconnection.
Deduced elasticity of sp3-bonded amorphous diamond
Authors: Ballato J. , Ballato A.
Published: November 2017

Amorphous diamond was recently synthesized using high temperature and pressure techniques [Z. Zeng, L. Yang, Q. Zeng, H. Lou, H. Sheng, J. Wen, D. J. Miller, Y. Meng, W. Yang, W. L. Mao, and H. K. Mao, Nat. Commun. 8, 322 (2017)]. Here, selected physical properties of this new phase of carbon are deduced using an extension of the Voigt-Reuss-Hill (VRHx) methodology whereby single crystal values are averaged over all orientations to yield values for the amorphous analog. Specifically, the elastic constants were deduced to be c11 = 1156.5 GPa, c12 = 87.6 GPa, and c44 = 534.5 GPa, whereas the Young's modulus, bulk modulus, and Poisson's ratio were also estimated to be 1144.2 GPa, 443.9 GPa, and 0.0704, respectively. These numbers are compared with experimental and theoretical literature values for other allotropic forms, specifically, Lonsdaleite, and two forms each of graphite and amorphous carbon. It is unknown at this time how the high temperature and pressure synthesis approach employed influences the structure, hence properties, of amorphous diamond at room temperature. However, the values provided herein constitute a baseline against which future structure/property/processing analyses can be compared.
Communication: Coordinate-dependent diffusivity from single molecule trajectories
Authors: Berezhkovskii Alexander M. , Makarov Dmitrii E.
Published: November 2017

Single-molecule observations of biomolecular folding are commonly interpreted using the model of one-dimensional diffusion along a reaction coordinate, with a coordinate-independent diffusion coefficient. Recent analysis, however, suggests that more general models are required to account for single-molecule measurements performed with high temporal resolution. Here, we consider one such generalization: a model where the diffusion coefficient can be an arbitrary function of the reaction coordinate. Assuming Brownian dynamics along this coordinate, we derive an exact expression for the coordinate-dependent diffusivity in terms of the splitting probability within an arbitrarily chosen interval and the mean transition path time between the interval boundaries. This formula can be used to estimate the effective diffusion coefficient along a reaction coordinate directly from single-molecule trajectories.
X-ray source on the basis of the piroelectric crystal Sr0.61Ba0.39Nb2O6
Authors: Andrianov V. A. , Erzinkian A. L. , Ivleva L. I. , Lykov P. A.
Published: November 2017

The properties of X-ray source based on Sr0.61Ba0.39Nb2O6 crystals (SBN-61) having a large pyroelectric coefficient γ = 85 nC/(cm2K) was studied. When the crystal was heated to 60 ° C, X-rays from a tungsten target with energy of 8.4 keV were detected. The maximum energy of the electron beam was 52 keV. The visualization of the electron beam with a grid electrode and a fluorescent screen showed that the electron beam was inhomogeneous in the polar plane of the crystal and varied during heating.The radiation intensity was unstable in time. The work of the X-ray source was limited to electrical breakdowns between the polar faces of the crystal. When the crystal was cooled, there was no X-ray emission, which could be due to the depolarization of the crystal by the total electric field or as a result of electrical breakdowns. The crystals SBN-61 and LiNbO3 are compared.
Geodesics in nonexpanding impulsive gravitational waves with Λ. II
Authors: Sämann Clemens , Steinbauer Roland
Published: November 2017

We investigate all geodesics in the entire class of nonexpanding impulsive gravitational waves propagating in an (anti-)de Sitter universe using the distributional metric. We extend the regularization approach of part I [Sämann, C. et al., Classical Quantum Gravity 33(11), 115002 (2016)] to a full nonlinear distributional analysis within the geometric theory of generalized functions. We prove global existence and uniqueness of geodesics that cross the impulsive wave and hence geodesic completeness in full generality for this class of low regularity spacetimes. This, in particular, prepares the ground for a mathematically rigorous account on the “physical equivalence” of the continuous form with the distributional “form” of the metric.
Multiplexed fluctuation-dissipation-theorem calibration of optical tweezers inside living cells
Authors: Yan Hao , Johnston Jessica F. , Cahn Sidney B. , King Megan C. , Mochrie Simon G. J.
Published: November 2017

In order to apply optical tweezers-based force measurements within an uncharacterized viscoelastic medium such as the cytoplasm of a living cell, a quantitative calibration method that may be applied in this complex environment is needed. We describe an improved version of the fluctuation-dissipation-theorem calibration method, which has been developed to perform in situ calibration in viscoelastic media without prior knowledge of the trapped object. Using this calibration procedure, it is possible to extract values of the medium’s viscoelastic moduli as well as the force constant describing the optical trap. To demonstrate our method, we calibrate an optical trap in water, in polyethylene oxide solutions of different concentrations, and inside living fission yeast (S. pombe).
Catalytic activity and mechanism of ordered mesoporous iron oxides on hydrogen peroxide for degradation of norfloxacin in water at neutral pH
Authors: Yuan Zhen , Sui Minghao , Yang Jianrui , Li Pan , Liu Zhiran , Sheng Li
Published: November 2017

Environmental contextNorfloxacin is widely used as a human and veterinary medicine for its broad-spectrum antibacterial activity. It is chemically stable, rendering it difficult to remove from water using the traditional water and wastewater treatment techniques. We investigate the use of iron oxide catalysts for the degradation of norfloxacin in water prior to its release into the environment. AbstractThe catalytic activity of ordered mesoporous Fe2O3 (om-Fe2O3) on H2O2 oxidation of norfloxacin (NOR) under neutral pH conditions in water was investigated. Using non-ordered-mesoporous Fe2O3 as a reference (nom-Fe2O3), om-Fe2O3 with high specific surface area of 176.4m2g−1 and a uniform pore structure exhibited high catalytic activity in the decomposition of H2O2 as well as the degradation of NOR at neutral pH. Compared with nom-Fe2O3, om-Fe2O3 promoted the decomposition of H2O2 differently. The adsorption capacity of om-Fe2O3 for NOR was much higher than that of nom-Fe2O3. The adsorption efficiency of NOR on om-Fe2O3 accounted for 60.2–64.9% of the degradation efficiency in om-Fe2O3/H2O2. tert-Butanol (TBA), which is resistant to adsorption by om-Fe2O3, had no effect on the degradation of NOR by om-Fe2O3/H2O2. However, the presence of tromethamine (TMA), which was favourable to adsorption by om-Fe2O3, inhibited the degradation of NOR significantly. Based on the different effects of TBA and TMA on the degradation of NOR, it is proposed that the catalytic degradation of NOR may occur on the surface of om-Fe2O3. Hydroxyl radicals (·OH) generated may be bound on the surface of om-Fe2O3 without diffusing into aqueous solution. It is proposed that the adsorption of target organic pollutants must be considered when assessing the suitability of the om-Fe2O3/H2O2 process. The mechanism of om-Fe2O3 in promoting H2O2 decomposition into OH was also investigated.
Using deep learning and Google Street View to estimate the demographic makeup of neighborhoods across the United States
Authors: Gebru Timnit , Krause Jonathan , Wang Yilun , Chen Duyun , Deng Jia , Aiden Erez Lieberman , Fei-Fei Li
Published: November 2017

Significance

We show that socioeconomic attributes such as income, race, education, and voting patterns can be inferred from cars detected in Google Street View images using deep learning. Our model works by discovering associations between cars and people. For example, if the number of sedans in a city is higher than the number of pickup trucks, that city is likely to vote for a Democrat in the next presidential election (88% chance); if not, then the city is likely to vote for a Republican (82% chance).
Equilibration of energy in slow–fast systems
Authors: Shah Kushal , Turaev Dmitry , Gelfreich Vassili , Rom-Kedar Vered
Published: November 2017

Significance

Do partial energies in slow–fast Hamiltonian systems equilibrate? This is a long-standing problem related to the foundation of statistical mechanics. Altering the traditional ergodic assumption, we propose that nonergodicity in the fast subsystem leads to equilibration of the whole system. To show this principle, we introduce a set of mechanical toy models—the springy billiards—and describe stochastic processes corresponding to their adiabatic behavior. We expect that these models and this principle will play an important role in the quest to establish and study the underlying postulates of statistical mechanics, one of the long-standing scientific grails.
Inequality in nature and society
Authors: Scheffer Marten , van Bavel Bas , van de Leemput Ingrid A. , van Nes Egbert H.
Published: November 2017

Significance

Inequality is one of the main drivers of social tension. We show striking similarities between patterns of inequality between species abundances in nature and wealth in society. We demonstrate that in the absence of equalizing forces, such large inequality will arise from chance alone. While natural enemies have an equalizing effect in nature, inequality in societies can be suppressed by wealth-equalizing institutions. However, over the past millennium, such institutions have been weakened during periods of societal upscaling. Our analysis suggests that due to the very same mathematical principle that rules natural communities (indeed, a “law of nature”) extreme wealth inequality is inevitable in a globalizing world unless effective wealth-equalizing institutions are installed on a global scale.
Proteomics of phosphorylation and protein dynamics during fertilization and meiotic exit in the
Xenopus
egg
Authors: Presler Marc , Van Itallie Elizabeth , Klein Allon M. , Kunz Ryan , Coughlin Margaret L. , Peshkin Leonid , Gygi Steven P. , Wühr Martin , Kirschner Marc W.
Published: November 2017

Significance

Protein phosphorylation and degradation drive critical events in early embryogenesis and the cell cycle; however, comprehensive and accurate analysis of these changes is currently difficult. Using a mass-spectrometric approach, we present a quantitative view of the protein and posttranslational economy of the fertilization response in the frog egg. Protein degradation affects a small but very important class of proteins, while regulatory phosphorylation and protein release occur on a far larger scale. We have developed broadly applicable analytical methods for phosphorylation that provide absolute quantification with confidence intervals for improved interpretability of posttranslational modification analysis.
Precision genome editing using synthesis-dependent repair of Cas9-induced DNA breaks
Authors: Paix Alexandre , Folkmann Andrew , Goldman Daniel H. , Kulaga Heather , Grzelak Michael J. , Rasoloson Dominique , Paidemarry Supriya , Green Rachel , Reed Randall R. , Seydoux Geraldine
Published: November 2017

Significance

Genome editing, the introduction of precise changes in the genome, is revolutionizing our ability to decode the genome. Here we describe a simple method for genome editing in mammalian cells that takes advantage of an efficient mechanism for gene conversion that utilizes linear donors. We demonstrate that PCR fragments containing edits up to 1 kb require only 35-bp homology sequences to initiate repair of Cas9-induced double-stranded breaks in human cells and mouse embryos. We experimentally determine donor DNA design rules that maximize the recovery of edits without cloning or selection.
Metagenomics-guided analysis of microbial chemolithoautotrophic phosphite oxidation yields evidence of a seventh natural CO
2
fixation pathway
Authors: Figueroa Israel A. , Barnum Tyler P. , Somasekhar Pranav Y. , Carlström Charlotte I. , Engelbrektson Anna L. , Coates John D.
Published: November 2017

Significance

Phosphite (HPO
3
2−
) is the most energetically favorable biological electron donor known, but only one organism capable of growing by phosphite oxidation has been previously identified. Here, we describe a phosphite-oxidizing bacterium that can grow with CO
2
as its sole electron acceptor, and we propose a metabolic model in which inorganic carbon is assimilated via the reductive glycine pathway. Although the reductive glycine pathway has previously been identified as a “synthetic” carbon fixation pathway, this study provides evidence that it may actually function as a natural autotrophic pathway. Our results suggest that phosphite may serve as a driver of microbial growth and carbon fixation in energy-limited environments, particularly in aphotic environments lacking alternative terminal electron acceptors.
Catch bond drives stator mechanosensitivity in the bacterial flagellar motor
Authors: Nord Ashley L , Gachon Emilie , Perez-Carrasco Ruben , Nirody Jasmine A. , Barducci Alessandro , Berry Richard M. , Pedaci Francesco
Published: November 2017

Significance

The bacterial flagellar motor (BFM) is the rotary motor powering swimming of many motile bacteria. Many of the components of this molecular machine are dynamic, a property which allows the cell to optimize its behavior in accordance with the surrounding environment. A prime example is the stator unit, a membrane-bound ion channel that is responsible for applying torque to the rotor. The stator units are mechanosensitive, with the number of engaged units dependent on the viscous load on the motor. We measure the kinetics of the stators as a function of the viscous load and find that the mechanosensitivity of the BFM is governed by a catch bond: a counterintuitive type of bond that becomes stronger under force.
Contrasting pronominal subjects
Authors: Pisanski Peterlin Agnes , Mikolič Južnič Tamara
Published: November 2017

Pronominal subject use constitutes a potential challenge in translation because of cross-linguistic differences: while the subject must be expressed in non-null subject languages, this is not necessary in null subject languages. The aim of the paper is twofold: first, to show that the type of source language influences the frequency of personal pronouns in translation, and second, to establish whether translations into a null subject language differ from comparable target language originals in terms of pronominal subject use. The study is based on the analysis of a 625,000-word corpus comprising original and translated popular science texts in Slovene and the corresponding source texts in English and Italian. The results confirm that pronominal subjects are more frequent in translations from English, a non-null subject language; furthermore, they are more frequent in translations than in comparable originals. Untypical cohesive patterns are identified in translations and possible reasons for their presence are explored.
Suppressive effect of nobiletin and epicatechin gallate on fructose uptake in human intestinal epithelial Caco-2 cells
Authors: Satsu Hideo , Awara Sohei , Unno Tomonori , Shimizu Makoto
Published: December 2017

Inhibition of excessive fructose intake in the small intestine could alleviate fructose-induced diseases such as hypertension and non-alcoholic fatty liver disease. We examined the effect of phytochemicals on fructose uptake using human intestinal epithelial-like Caco-2 cells which express the fructose transporter, GLUT5. Among 35 phytochemicals tested, five, including nobiletin and epicatechin gallate (ECg), markedly inhibited fructose uptake. Nobiletin and ECg also inhibited the uptake of glucose but not of L-leucine or Gly-Sar, suggesting an inhibitory effect specific to monosaccharide transporters. Kinetic analysis further suggested that this reduction in fructose uptake was associated with a decrease in the apparent number of cell-surface GLUT5 molecules, and not with a change in the affinity of GLUT5 for fructose. Lastly, nobiletin and ECg suppressed the permeation of fructose across Caco-2 cell monolayers. These findings suggest that nobiletin and ECg are good candidates for preventing diseases caused by excessive fructose intake.
Subcellular localization of aphidicolin biosynthetic enzymes heterologously expressed in Aspergillus oryzae
Authors: Ban Akihiko , Tanaka Mizuki , Fujii Ryuya , Minami Atsushi , Oikawa Hideaki , Shintani Takahiro , Gomi Katsuya
Published: December 2017

The secondary metabolite aphidicolin has previously been produced by Aspergillus oryzae after the heterologous expression of four biosynthetic enzymes isolated from Phoma betae. In this study, we examined the subcellular localization of aphidicolin biosynthetic enzymes in A. oryzae. Fusion of green fluorescent protein to each enzyme showed that geranylgeranyl diphosphate synthase and terpene cyclase are localized to the cytoplasm and the two monooxygenases (PbP450-1 and PbP450-2) are localized to the endoplasmic reticulum (ER). Protease protection assays revealed that the catalytic domain of both PbP450s was cytoplasmic. Deletion of transmembrane domains from both PbP450s resulted in the loss of ER localization. Particularly, a PbP450-1 mutant lacking the transmembrane domain was localized to dot-like structures, but did not colocalize with any known organelle markers. Aphidicolin biosynthesis was nearly abrogated by deletion of the transmembrane domain from PbP450-1. These results suggest that ER localization of PbP450-1 is important for aphidicolin biosynthesis.