bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Frequency and Duration of Interrupting Sitting on Cardiometabolic Risk Markers
Authors: Maylor Benjamin D. , Zakrzewski-Fruer Julia K. , Stensel David J. , Orton Charlie J. , Bailey Daniel P.
Published: September 2019

Interrupting prolonged sitting with short multiple bouts of moderate-intensity physical activity (PA) can improve postprandial cardiometabolic risk markers. This study examined the effect of high and low frequency PA bouts (matched for total PA duration and energy expenditure) on postprandial cardiometabolic responses when compared with prolonged sitting. In this three-condition randomised crossover trial, 14 sedentary, inactive females (33.8±13.4 years, BMI 27.1±6.3 kg/m2) completed 3, 7.5 h conditions: 1) prolonged sitting (SIT), 2) high-frequency PA breaks (HIGH-FREQ) consisting of 15 ×2 min bouts of moderate-intensity treadmill PA every 30 min, and 3) low-frequency PA breaks (LOW-FREQ) consisting of 3 ×10 min bouts of moderate-intensity treadmill PA every 180 min. The PA bouts were performed at 65% of peak oxygen uptake. Net incremental area under the curve (iAUC) for each 7.5 h condition was calculated for glucose, insulin and triacylglycerol (TAG) concentrations. Insulin iAUC was significantly (p<0.026) lower during HIGH-FREQ (mean [95%CI]; 82.86 [55.02, 110.70] µU/mL∙7.5 h) than LOW-FREQ (116.61 [88.50, 144.73] µU/mL∙7.5 h) and SIT (119.98 [92.42, 147.53] µU/mL∙7.5 h). Glucose and TAG iAUC did not differ between conditions. Engaging in higher-frequency PA breaks may be effective in attenuating postprandial insulin responses compared with lower-frequency PA breaks and prolonged sitting.
Contrasting Role of Concentration in Rivaroxaban Induced Toxicity and Oxidative Stress in Isolated Kidney Mitochondria
Authors: Samiei Fatemeh , Sajjadi Hanieh , Jamshidzadeh Akram , Seydi Enayatollah , Pourahmad Jalal
Published: September 2019

Rivaroxaban as a small molecule is able to directly and reversibly inhibit the factor Xa. This study was designed to figure out the evaluation effect of rivaroxaban on mitochondria obtained from rat kidneys. We isolated mitochondria from rat kidneys using gradient centrifugation. Then, the toxicity parameters including succinate dehydrogenase (SDH) activity, reactive oxygen species (ROS) formation, mitochondrial swelling, mitochondrial membrane potential (MMP) collapse and cytochrome c release were measured in kidneys mitochondria following the exposure to rivaroxaban. The results showed that rivaroxaban (1.4 and 2.8 mM) raised the reactive oxygen species (ROS) generation, swelling in the mitochondria, collapse in the mitochondrial membrane potential (MMP) and cytochrome c release in the mitochondria isolated from kidneys. While, rivaroxaban at a higher concentration of 5.6 mM showed the opposite effect compared to other lower concentrations. The results indicate that rivaroxaban may have antioxidant effects at high concentrations. The results suggest that rivaroxaban (5.6 mM) has protective effects against oxidative stress and mitochondrial toxicity.
Reliabilität und Validität des
Bregma-Tests
Authors: Best Norman , Senftleben Ulrike , Rottländer Kerstin , Lehmann Thomas , Loudovici-Krug Dana
Published: September 2019

Ziel der Studie Der Bregma-Test dient der Evaluation der posturalen
Funktion und damit der Einschätzung der physiologischen
Körperhaltung. Ziel der Studie war die Überprüfung
der Testgütekriterien „Reliabilität“ und
„Validität“ sowie die klinische bzw. praktische
Anwendbarkeit des Bregma-Tests.

Methodik Zweiteiliges Studiendesign mit n=20 Probanden und
n=61 Patienten zur Prüfung der Intra- bzw.
Interrater-Reliabilität. Unterscheidung zwischen erfahrenen und
unerfahrenen Untersuchern sowie Prüfung der Reliabilität
zwischen klinischer Auswertung und Auswertung angefertigter Videosequenzen.
Errechnung linear gewichteter Kappa-Werte. Prüfung der
Validität bei fehlendem Goldstandard über einen
Delphi-Prozess.

Ergebnisse Intrarater-Reliabilität mit fast vollkommener
Übereinstimmung, beachtliche Interrater-Reliabilität, auch
bei Auswertung der Videosequenzanalyse. Hohe Praktikabilität.
Vollkommene Zustimmung eines Expertengremiums im Delphi-Prozess.

Schlussfolgerung Der Bregma-Test ist ein reliables Instrument zur
Überprüfung allgemeiner sensomotorischer Fähigkeiten
im klinischen Setting und somit auch im Rehabilitationsprozess.
Clinical Impact of BioFire Film Array in Pediatric Sepsis
Authors: Moraru Gabriela M. , Chatani Brandon , Martinez Octavio , Scott Gwendolyn , Tamariz Leonardo , Mitchell Charles D.
Published: September 2019

Objective Rapid molecular tests are important components of antimicrobial stewardship programs (ASP) and for early and accurate diagnosis of sepsis etiology. Their utility in helping providers to de-escalate therapy remains a subject of debate, especially among patients with chronic conditions and indwelling devices.

Methods We have conducted a retrospective cohort study of medical records from August 1, 2016 to July 31, 2018, following the implementation at our institution of the BioFire FilmArray blood culture identification panel (BioFire Diagnostics, Salt Lake City, Utah, United States). We have assessed the clinical impact of the assay looking at antimicrobial optimization and time needed to make this change in different pediatric wards.

Results Two hundred and twenty-nine patients were included in our analysis. We identified a significant statistical difference between different pediatric wards regarding antimicrobial therapy optimization (p < 0.001) and between the type of therapeutic attitude related to BioFire result, escalation versus de-escalation, or no change (p < 0.03). The likelihood for an infectious disease consult requested upon BioFire result to lead to an antimicrobial regimen optimization was also statistically significant (p < 0.01). The positive BioFire results were associated with antimicrobial escalation in 81.4% of cases, with approximately 75% of changes made within 12 hours of the assay result.

Conclusion Our study suggests that BioFire Film Array does not help de-escalating the therapy in patients with chronic disorders. Physician education and level of confidence in the assay remains an essential obstacle in maximizing the test performance in clinical practice. In recent years, the market for more sensitive and comprehensive rapid molecular diagnostic tests has evolved rapidly, requiring effective ASP to optimize the management of infectious diseases.
Total Knee Arthroplasty among Medicare Beneficiaries with Hemophilia A and B Is Associated with Increased Complications and Higher Costs
Authors: Rosas Samuel , Buller Leonard T. , Plate Johannes , Higuera Carlos , Barsoum Wael K. , Emory Cynthia
Published: September 2019

Operations on patients with hemophilia A and B are complex. Studies evaluating postoperative outcomes and costs following total knee arthroplasty (TKA) in patients with hemophilia are limited. A retrospective review of the entire Medicare dataset from 2005 to 2014 was performed. International Classification of Disease 9th revision codes were used to identify patients with hemophilia A and B and they were matched to controls using a 1:1 random matching process based on age, gender, Charlson Comorbidity Index (CCI), and select comorbidity burden. The 90-day preoperative period was evaluated for comorbidities and the 90-day postoperative period was analyzed for outcomes and reimbursements. Logistic regression models were generated to compare outcomes between cases and controls. A total of 4,034 patients with hemophilia were identified as having undergone TKA. About 44.8% were between the ages of 65 and 74 and 62.4% were female. Although the CCI was identical in both cohorts, individual comorbidities not controlled for varied significantly. Medical complications were more frequent among the patients with hemophilia: postoperative bleeding (odds ratio [OR]: 1.7; 95% confidence interval [CI]: 1.2–2.3), deep venous thrombosis (OR: 2.3; 95% CI: 1.8–2.8), pulmonary embolism (OR: 2.9; 95% CI: 2.1–3.9), and blood transfusions (OR: 1.8; 95% CI: 1.6–1.9). Hemophilia was associated with higher odds of periprosthetic infection (1.78 vs. 0.98%, OR: 1.8 95% CI: 1.2–2.7). The 90-day reimbursements were higher for patients with hemophilia (mean: $22,249 vs. $13,017, p < 0.001). Medicare beneficiaries with a diagnosis of hemophilia experience more frequent postoperative complications and incur greater 90-day costs than matched controls following TKA. Surgeons should consider this when optimizing patients for TKA and payors should consider this for risk-adjusting payment models.
Amputations versus Salvage: Reconciling the Differences
Authors: Black Cara K. , Ormiston Laurel D. , Fan Kenneth L. , Kotha Vikas S. , Attinger Christopher , Evans Karen Kim
Published: September 2019

Background There are many factors to consider when choosing between amputations versus salvage in lower extremity reconstructive surgery. Postoperative functionality and survival benefit are critical factors when deciding between limb salvage and amputation.

Methods In this review, we present the evidence and the risks and benefits between these two options in the setting of the acute, trauma population and the chronic, diabetes population.

Results The trauma population is on average young without significant comorbidities and with robust vasculature and core strength for recovery. Therefore, these patients can often recover significant function with anamputation and prosthesis. Amputation can therefore be the more desirable in this patient population, especially in the case of complete traumatic disruption, unstable patients, high risk of extensive infection, and significant nerve injury. However, traumatic lower extremity reconstruction is also a viable option, especially in the case of young patients and those with intact plantar sensation and sufficient available tissue coverage. The diabetic population with lower extremity insult has on average a higher comorbidity profile and often lower core strength. These patients therefore often benefit most from reconstruction to preserve limb length and improve survival. However, amputation may be favored for diabetics that have no blood flow to the lower extremity, recalcitrant infection, high-risk comorbidities that preclude multiple operations, and those with end stage renal disease.

Conclusion Many patient-specific factors should be considered when deciding between amputation vs. salvage in the lower extremity reconstruction population.
Observation of thermoacoustic chaotic oscillations in a looped tube
Authors: Delage Rémi , Takayama Yusuke , Hyodo Hiroaki , Biwa Tetsushi
Published: September 2019

This study presents experimental observations of chaotic thermoacoustic oscillations induced in a looped tube with respect to both temporal and spatial dimensions and compares them with those in a resonance tube system. The wave propagation directions observed in thermoacoustic systems showing periodic behaviors are confirmed in the chaotic case, from cold to hot sides in the stack in a looped system, and with reflections at the ends of a resonance tube system. Although both systems are similar in their route to chaos and correlation dimensions of the chaotic attractor, a recurrence visualization method reveals differences in the distribution of temporal patterns resulting from the mode competition between the natural frequencies of the systems.
A piezoelectric stick-slip linear actuator with a rhombus-type flexure hinge mechanism by means of parasitic motion
Authors: Gao Qi , Li Yikang , Lu Xiaohui , Zhang Chi , Zhang Xiaosong , Cheng Tinghai
Published: September 2019

In order to obtain the high velocity in compact size, a piezoelectric stick-slip linear actuator is proposed in this paper. The proposed actuator adopts rhombus-type flexure hinge mechanism which can be used as a displacement amplifier which can easily produce a parasitic motion. The working principle of the proposed actuator is discussed, and the finite element method is adopted to verify the generation of parasitic motion of the flexure hinge mechanism. A prototype is manufactured to investigate the working performance. The prototype achieves a maximum velocity of 13.08 mm/s at a frequency of 570 Hz under the sawtooth wave exciting voltage of 100 Vp-p. The maximum efficiency is about 1.26% with a load of 135 g and velocity of 7.12 mm/s.
One-dimensional nonlinear analysis of sine waveguide traveling-wave tubes
Authors: Lei Xia , Zhao Yue , Fang Shuanzhu , Li Qian , Wu Gangxiong , Yin Pengcheng , Jiang Xuebing , Yin Hairong , Xu Jin , Yue Lingna , Wei Yanyu , Liu Wenxin
Published: September 2019

A 1D frequency-domain nonlinear model for illustrating the beam-wave interactions of sine waveguide (SWG) traveling-wave tubes (TWTs) was studied. Our model considered space-charge fields and Ohmic losses to make the model closer to practical situations. The sheet beam was split into a series of rectangular electron plates in the axial direction, and the space-charge field was calculated by solving Green's function. The dynamic equations and relativistic equations of motion were solved self-consistently to obtain the nonlinear characteristics of the power saturation, as well as the electron velocity, phase space distributions, etc. A 0.22 THz SWG TWT was used to illustrate and verify the validity of the theoretical model. The output power and gain results were in good agreement with those from the Computer Simulation Technology (CST) 3D particle-in-cell simulation. In addition, the code developed based upon the theoretical model produced faster results than the CST simulation.
Proton acceleration due to laser plasma interactions from mass-limited spherical targets
Authors: Bhagawati Ankita , Kuri Deep Kumar , Das Nilakshi
Published: September 2019

The proton acceleration processes involved in the interaction of an ultrashort circularly polarized laser with a near-critical density spherical target are investigated in this paper using three dimensional particles in cell simulations. Both the target size and the target density are varied to understand their influence on the accelerated beam of protons. The target is efficiently heated by relativistic transparency, and a complicated interplay is observed between the participating interaction processes. The electron heating and recirculations help in the formation of shocks which exert a further push to the protons accelerated by the electrostatic sheath formed due to the ponderomotive force. A maximum peak proton energy of about 40 MeV is observed, which is the result of the cumulative effects of various acceleration mechanisms. Electron jets are observed in the forward laser direction for the larger target size, which suppresses the energy of the proton beams.
Propagation of circularly polarized laser in strongly magnetized over-dense collisional plasma
Authors: Li K. , Yu W.
Published: September 2019

Permittivity of a circularly polarized (CP) laser in magnetized collisional plasma is obtained in simplified form. The propagation of a CP laser in magnetized homogeneous over-dense collisional plasma was investigated, and characteristics such as attenuation length, specific energy deposition and blue shift are obtained. Potential applications in fields such as inertial confined fusion are discussed.
Approximating dynamic proximity with a hybrid geometry energy-based kernel for diffusion maps
Authors: Tan Qingzhe , Duan Mojie , Li Minghai , Han Li , Huo Shuanghong
Published: September 2019

The diffusion map is a dimensionality reduction method. The reduction coordinates are associated with the leading eigenfunctions of the backward Fokker–Planck operator, providing a dynamic meaning for these coordinates. One of the key factors that affect the accuracy of diffusion map embedding is the dynamic measure implemented in the Gaussian kernel. A common practice in diffusion map study of molecular systems is to approximate dynamic proximity with RMSD (root-mean-square deviation). In this paper, we present a hybrid geometry-energy based kernel. Since high energy-barriers may exist between geometrically similar conformations, taking both RMSD and energy difference into account in the kernel can better describe conformational transitions between neighboring conformations and lead to accurate embedding. We applied our diffusion map method to the β-hairpin of the B1 domain of streptococcal protein G and to Trp-cage. Our results in β-hairpin show that the diffusion map embedding achieves better results with the hybrid kernel than that with the RMSD-based kernel in terms of free energy landscape characterization and a new correlation measure between the cluster center Euclidean distances in the reduced-dimension space and the reciprocals of the total net flow between these clusters. In addition, our diffusion map analysis of the ultralong molecular dynamics trajectory of Trp-cage has provided a unified view of its folding mechanism. These promising results demonstrate the effectiveness of our diffusion map approach in the analysis of the dynamics and thermodynamics of molecular systems. The hybrid geometry-energy criterion could be also useful as a general dynamic measure for other purposes.
A new method for detecting thermal characteristics of slow-wave structure of helix traveling-wave tube using external heat source
Authors: He X. , Feng S. W. , Yang F. , Zhang Y. M.
Published: September 2019

This paper presents a method for detecting the heat-dissipation capability of the slow-wave structure (SWS) in a helix traveling wave tube (TWT) using an external heat source. This method utilizes transient temperature rise detection technology and structure function method to nondestructively detect the heat-dissipation capability of SWS. An analytical model is built, and the method is verified by using the simulation tool ANSYS. Furthermore, a dedicated test probe is designed based on this method, and a 2.5-mm diameter helix TWT is measured. The results reveal that the method can effectively detect parts with large thermal resistance in SWS, thereby providing the basis for eliminating the failure products and improving the production process of SWS.
High-sensitivity hydraulic pressure sensor based on Fabry-Perot interferometer filled with polydimethylsiloxane film
Authors: Zhao Chunliu , Hou Leyi , Kang Juan , Mao Bangning , Shen Changyu , Jin Shangzhong
Published: September 2019

A high-sensitivity hydraulic pressure sensor is proposed, which consists of a Fabry–Perot interferometer (FPI) filled with a polymer film of polydimethylsiloxane (PDMS). The FPI structure is fabricated by splicing a section of hollow core fiber (HCF) to the end-face of a lead-in single mode fiber (SMF). Then, the PDMS is filled into the HCF which acts as a light reflector and a diaphragm to detect external pressure variation. As a result, the length of the FPI cavity and the thickness of the PDMS are 137.8 µm and 33.8 µm, respectively. Experimental results indicate that the sensor’s wavelength exhibits a linear response to the hydraulic pressure, which function is described as y = −7.35 × 10−3x + 1536.395. Here, x and y represent the hydraulic pressure and the wavelength, respectively. The pressure sensitivity is up to −7.35 nm/kPa. Besides, a temperature compensation method based on a fiber Bragg grating is proposed to eliminate the influence of temperature. Experiments show that the scheme can effectively eliminate the influence of temperature and achieve accurate measurement of hydraulic pressure.
Performance limits of vertical GaN of conventional doped pn and natural polarization superjunction devices
Authors: Zhou X. , Howell-Clark J. R. , Guo Z. , Hitchcock C. W. , Chow T. P.
Published: September 2019

We have determined and evaluated the specific on-resistance (Ron,sp) vs breakdown voltage (BV) trade-off limits of vertical GaN-based conventional doped pn superjunction (SJ) and natural polarization superjunction (PSJ) devices using analytical models and numerical simulations. We have obtained much better performance on the vertical natural polarization superjunction devices based on the AlGaN/GaN and AlInN/GaN heterostructures instead of the conventional superjunction devices with alternating doped p/n pillars. Our results show that the drift-region Ron,sp of vertical GaN-based superjunction devices is one to more than four orders of magnitude lower than the 1D limit of GaN conventional unipolar devices at the same BV. For 1 and 10 kV devices, the optimized specific on-resistance of the drift region is about 10 and 300 times lower for conventional superjunction devices, but 1000 and 20 000 times lower for natural polarization superjunction devices.
Flapping dynamics of a flexible plate with Navier slip
Authors: Ryu Jaeha , Byeon Hyeokjun , Lee Sang Joon , Sung Hyung Jin
Published: September 2019

Seaweed and fish have slippery outer surfaces because of the secretion of a layer of mucus. Navier slip arises when the component of the tangential velocity at a wall is proportional to the strain. The hydrodynamics of a three-dimensional flexible plate with Navier slip was explored by using the immersed boundary method in an effort to scrutinize the effects on plate hydrodynamics of a slip boundary mimicking the mucus layers of seaweed and fish. For comparison, simulations with the no-slip condition were also performed. Two cases were chosen for simulation: a flexible plate with a fixed leading edge and a flexible plate with a heaving leading edge in a uniform flow. For the fixed plate, the velocity gradient and the total drag were determined to examine the influence of the slip surface. Drag was significantly reduced by the slip. The slip surface lessens the velocity gradient near the wall and suppresses the flapping motion. The drag reduction process was characterized by using the distributions of vorticity and pressure. The hydrodynamics of the heaving flexible plate with Navier slip was explored in terms of thrust generation. The flapping motion was mainly governed by the input heaving condition and a large form drag was exerted on the flexible plate. The net thrust, input power, and Froude efficiency were determined as a function of the bending rigidity. A large net thrust for the heaving plate was generated by the slip. The velocity ratio was employed to interpret the correlation between the slip velocity and the flapping motion.
Evolution of structure and dynamics of thermo-reversible nanoparticle gels—A combined XPCS and rheology study
Authors: Bahadur Divya , Zhang Qingteng , Dufresne Eric M. , Grybos Pawel , Kmon Piotr , Leheny Robert L. , Maj Piotr , Narayanan Suresh , Szczygiel Robert , Swan James W. , Sandy Alec , Ramakrishnan Subramanian
Published: September 2019

A combined X-ray photon correlation spectroscopy and rheology study is carried out to capture the evolution of structure, fast particle-scale dynamics, and moduli (elastic and loss) at early times of gel formation near the fluid–gel boundary of a suspension of nanoparticles. The system is comprised of moderately concentrated suspensions of octadecyl silica in decalin (ϕ = 0.2) undergoing thermoreversible gelation. Near the gel boundary, the rate of gel formation is very sensitive to changes in attraction strength. However, we find that at different attraction strengths, the system goes through identical intermediate states of microscopic and macroscopic behavior, even though the absolute time needed to form a gel varies by orders of magnitude. We identify a single dimensionless time parameter, tw/tg, where tw is the wait time following the quench and tg is the rheologically determined gel time, that captures the similarity in gel formation at a range of attraction strengths. Following a temperature quench below the gel boundary, the system is initially fluidlike and forms diffusive clusters (∼8.5 times the particle diameter). After a lag-time, tL, clusters aggregate to form a network like structure which is characterized by the onset of mechanical rigidity and a rapid growth in microscopic relaxation times. At tg, the Baxter parameter obtained from adhesive hard sphere fits of the structure factor attains a constant value corresponding to the theoretical percolation boundary, thus demonstrating that gelation is percolation driven.
Impact of electric potential and magnetic drift on microtearing modes stability
Authors: Hamed M. , Muraglia M. , Camenen Y. , Garbet X. , Agullo O.
Published: September 2019

The stability of a microtearing mode (MTM) as a function of collisionality is investigated by means of a linear reduced model and numerical simulations using the gyrokinetic code GKW. This study is focused on the role of the electric potential and the magnetic drift, which are potential candidates for explaining the destabilization of MTM observed at low collisionality in some recent gyrokinetic simulations. In the simulations, the magnetic drift and electric potential are found to be destabilizing in the presence of a finite collisionality. This destabilizating role is captured in the analytical calculation, which further highlights the requirement for a finite collisionality.
Why does adding a poor thermal conductor increase propagation rate in solid propellants?
Authors: Kline Dylan J. , Rehwoldt Miles C. , Wang Haiyang , Eckman Noah E. , Zachariah Michael R.
Published: September 2019

Solid propellant additives have a long history of modulating burning rate by introducing materials with high thermal diffusivities to better concentrate and transfer heat to nearby areas. However, recent studies have demonstrated a counterintuitive result in that additives with thermally insulating properties—notably SiO2 particles—can also enhance the propagation rate in solid propellants. In this work, high-speed microscopy and thermometry were performed on 3D printed solid propellant films containing both thermally conducting (graphite) and insulating (SiO2) particles to investigate the role of these additives on film propagation rate. It was found that addition of SiO2 particles increased the effective surface area of the reaction front through inhomogeneous heat transfer in the films, and that such corrugation of the reaction front area on the micrometer scale manifests itself as a global increase in the propagation rate on the macro scale. Graphite additive was observed to have a substantially lower burning surface area and propagation rate, suggesting that the effect of reaction front surface area is larger than the effect of thermal diffusivity for low-weight percent additives in solid propellants.
Density-dependent finite system-size effects in equilibrium molecular dynamics estimation of shear viscosity: Hydrodynamic and configurational study
Authors: Kim Kang-Sahn , Kim Changho , Karniadakis George Em , Lee Eok Kyun , Kozak John J.
Published: September 2019

We study the intrinsic nature of the finite system-size effect in estimating shear viscosity of dilute and dense fluids within the framework of the Green–Kubo approach. From extensive molecular dynamics simulations, we observe that the size effect on shear viscosity is characterized by an oscillatory behavior with respect to system size L at high density and by a scaling behavior with an L−1 correction term at low density. Analysis of the potential contribution in the shear-stress autocorrelation function reveals that the former is configurational and is attributed to the inaccurate description of the long-range spatial correlations in finite systems. Observation of the long-time inverse-power decay in the kinetic contribution confirms its hydrodynamic nature. The L−1 correction term of shear viscosity is explained by the sensitive change in the long-time tail obtained from a finite system.
Modeling of streamer dynamics in helium plasma jets driven by modulated voltage pulses
Authors: Naidis G. V. , Babaeva N. Yu.
Published: September 2019

The results of simulation of guided streamers driven by modulated voltage pulses are presented. It is shown that, in qualitative accordance with recently obtained experimental data, modulation of the applied voltage can lead to oscillations of the streamer propagation velocity and provide stepwise character of streamer propagation. A comparison of streamer characteristics upon application of modulated and constant voltages, showing the effects of modulation on plasma jet characteristics, is given.
Probing gaseous molecular structure by molecular-frame photoelectron angular distributions
Authors: Fukuzawa Hironobu , Yamada Syuhei , Sakakibara Yuta , Tachibana Tetsuya , Ito Yuta , Takanashi Tsukasa , Nishiyama Toshiyuki , Sakai Tsukasa , Nagaya Kiyonobu , Saito Norio , Oura Masaki , Stener Mauro , Decleva Piero , Ueda Kiyoshi
Published: September 2019

Carbon 1s photoelectron angular distributions of an iodomethane molecule were measured relative to the recoil-frame determined by the momentum correlation between I+ and CH3+ at photoelectron energies of 3, 6.1, and 12 eV. The energy dependent behavior of the recoil-frame photoelectron angular distributions is reproduced reasonably well by the time-dependent density functional theory with B-spline methods. We discuss potential applications of the fully differential photoelectron angular distribution measurements in the molecular frame to three-dimensional molecular structural determinations identifying the directions and lengths of the bonds.
Very low activation energy for carrier generation of surface doped organic single crystals observed by Hall effects
Authors: Kikuchi Mitsuru , Izawa Seiichiro , Rai Nitish , Hiramoto Masahiro
Published: September 2019

Very low activation energy for hole generation reaching 5.7 meV to realize the ionization rate of 100% at room temperature by surface doping of molybdenum oxide on rubrene single crystals was observed from the temperature dependence of the hole concentration directly measured by the Hall effect. Hole mobility having band-conductive nature was maintained after surface doping. Very low activation energy can be explained by the overlap of shielded Coulomb potentials. By increasing the concentration of charge transfer states at the interface between the crystal and the dopant, high doping efficiency can be achieved.
Vectorial, non-destructive magnetic imaging with scanning tunneling microscopy in the field emission regime
Authors: Ramsperger U. , Pescia D.
Published: September 2019

When a scanning tunneling microscope is operated at tip-target distances ranging from few nanometers to few tens of nanometers (Fowler-Nordheim or field emission regime), a new electronic system appears, consisting of electrons that escape the tip-target junction. If the target is ferromagnetic, this electronic system is spin polarized. Here, we use these spin polarized electrons to image magnetic domains in thin films. As two components of the spin polarization vector are detected simultaneously, the imaging of the local magnetization has vectorial character. The tip is nonmagnetic, i.e., the magnetic state of the target is not perturbed by the act of probing. We expect this spin polarized technology, which scales down scanning electron microscopy with polarization analysis by bringing the source of primary electrons in close proximity to the target, to find its main applications in the imaging of noncollinear, weakly stable spin excitations.
Phase-field model of graphene aerogel formation by ice template method
Authors: Yang Chao , Zhu Xiangyu , Wang Xitao , Wang Junsheng , Huang Houbing
Published: September 2019

A phase-field model is exploited to simulate the microstructure of graphene aerogel formation during the water freezing process. The nucleation of ice grains and the graphene redistribution play significant roles in preparation of graphene aerogel by the ice template method. Our simulation clarifies the process of polycrystalline ice nucleation, the graphene redistribution between the ice-water interface and the anisotropic growth process of ice grains. The result shows that the morphology and size of the graphene wall structure in aerogel are derived from the comprehensive effects of ice nucleation, polycrystalline growth, and graphene diffusion. The present study therefore contributes to the understanding of graphene aerogel formation and provides guidance for experiments to design a high specific surface area, light weight, and high strength three-dimensional porous structure.
Generation of high-current pulses by a magnetized squeezed electron beam
Authors: Leopold J. G. , Bliokh Y. P. , Siman-Tov M. , Krasik Ya. E.
Published: September 2019

The space charge limited current of an electron beam generated in a magnetically insulated foil-less diode by a cylindrical or hollow cathode and injected into a cylindrical drift tube depends on the energy of the electrons and on the ratio of the beam radius to the tube radius. When this beam drifts into a tube of larger radius, it exceeds the corresponding space charge limit. This leads to the formation of a virtual cathode and to the reduction of the energy of the beam. The latter is known as a squeezed beam state. When the cylindrical tube consists of more segments of different radii and lengths, the dynamics of the beam can be manipulated. We propose a simple configuration resulting in the production of a high-frequency periodic train of high-current electron beam pulses.
Intertextuality in Practice
Authors: Mason Jessica
Published: September 2019

The books we’ve read, the films we’ve seen, the stories we’ve heard - and just as importantly the ones we haven’t – form an integral part of our identity. Recognising a reference to a text can result in feelings of pleasure, expertise and even smugness; being lost as to a reference’s possible significance can lead to alienation from a text or conversation. Intertextuality in Practice offers readers a cognitively-grounded framework for hands-on analysis of intertextuality, both in written texts and spoken discourse. The book offers a historical overview of existing research, highlighting that most of this work focuses on what intertextuality ‘is’ conceptually, rather than how it can be identified, described and analysed. Drawing on research from literary criticism, neuroscience, linguistics and sociology, this book proposes a cognitive stylistic approach, presenting the ‘narrative interrelation framework’ as a way of operationalising the concept of intertextuality to enable close practical analysis.
Glucose-conjugated chicken myofibrillar proteins derived from random-centroid optimization present potent hydroxyl radical scavenging activity
Authors: Nishimura Kimio , Suzuki Momoka , Saeki Hiroki
Published: September 2019

The optimal conditions for the preparation of glucose-conjugated chicken myofibrillar proteins (Mfs) via the Maillard reaction, presenting strong antioxidant activity against hydroxyl radicals (･OH) and high solubility in low ionic strength medium, were sought using random-centroid optimization (RCO). Four parameters of temperature, relative humidity (RH), reaction time, and glucose-to-Mfs mixing ratio, were examined, resulting in a total of 24 vertices. Evaluations were carried out relatively to each individual vertex, and the optimal preparatory conditions to obtain the highest antioxidant activity were determined as follows: temperature of 52 °C, RH of 38%, reaction time of 6.79 h, and a glucose to Mfs mixing ratio of 11.7 (w/w). The resulting glucose-conjugated chicken Mfs gained thermal gel-forming ability and its ･OH averting capacity reached 9.7 ± 0.7 μmol of gallic acid equivalent/g of protein.

Abbreviations: GA: gallic acid; HORAC: hydroxyl radical averting capacity; IC50: half-maximal inhibitory concentration; 2-ME, 2-mercaptoethanol; Mfs: myofibrillar proteins; MHC: myosin heavy chain; ･OH: hydroxyl radical; PAGE: polyacrylamide gel electrophoresis; RCO: random-centroid optimization; RH: relative humidity; RLU: relative light units; SDS: sodium dodecyl sulfate; SEM: scanning electron microscope; SS: disulfide
Modelling hierarchical flocking
Authors: Jia Yongnan , Vicsek Tamas
Published: September 2019

We present a general framework for modeling a wide selection of flocking scenarios under free boundary conditions. Several variants have been considered—including examples for the widely observed behavior of hierarchically interacting units. The models we have simulated correspond to classes of various realistic situations. Our primary goal was to investigate the stability of a flock in the presence of noise. Some of our findings are counter-intuitive in the first approximation, e.g. if the hierarchy is based purely on dominance (an uneven contribution of the neighbors to the decision about the direction of flight of a given individual) the flock is more prone to loose coherence due to perturbations even when a comparison with the standard egalitarian flock is made. Thus, we concentrated on building models based on leader-follower relationships. And, indeed, our findings support the concept that hierarchical organization can be very efficient in important practical cases, especially if the leader-follower interactions (corresponding to an underlying directed network of interactions) have several levels. Efficiency here is associated with remaining stable (coherent and cohesive) even in cases when collective motion is destroyed by random perturbations. The framework we present allows allows the study of several further complex interactions among the members of flocking agents.
The role of CALYPSO in the discovery of high-Tc hydrogen-rich superconductors*
Authors: Cui Wenwen , Li Yinwei
Published: September 2019

Hydrogen-rich compounds are promising candidates for high-T
c or even room-temperature superconductors. The search for high-T
c hydrides poses a major experimental challenge because there are many known hydrides and even more unknown hydrides with unusual stoichiometries under high pressure. The combination of crystal structure prediction and first-principles calculations has played an important role in the search for high-T
c hydrides, especially in guiding experimental synthesis. Crystal structure AnaLYsis by Particle Swarm Optimization (CALYPSO) is one of the most efficient methods for predicting stable or metastable structures from the chemical composition alone. This review summarizes the superconducting hydrides predicted using CALYPSO. We focus on two breakthroughs toward room-temperature superconductors initiated by CALYPSO: the prediction of high-T
c superconductivity in compressed hydrogen sulfide and lanthanum hydrides, both of which have been confirmed experimentally and have set new record T
c values. We also address the challenges and outlook in this field.
Selection of right-circular-polarized harmonics from p orbital of neon atom by two-color bicircular laser fields*
Authors: Xia Chang-Long , Lan Yue-Yue , Li Qian-Qian , Miao Xiang-Yang
Published: September 2019

The polarization properties of high-order harmonic generation (HHG) in the two-color circularly polarized laser fields are investigated by numerically solving the two-dimensional time-dependent Schrödinger equation. By adding a wavelength of 1600-nm right-circular-polarized field to an 800-nm left-circular-polarized field, HHG is simulated from a real model of neon atom with p orbital, but not from a hydrogen-like atom model with s orbital. The orders of 3n+1 can be selected while the orders of 3n+2 are suppressed by adjusting the intensities of the two pulses. The physical mechanism is analyzed by time–frequency analysis and semiclassical model.
Hubbard model on an anisotropic checkerboard lattice at finite temperatures: Magnetic and metal–insulator transitions
Authors: Liu Hai-Di
Published: September 2019

We study magnetic and Mott transitions of the Hubbard model on the geometrically frustrated anisotropic checkerboard lattice at half filling using cellular dynamical mean-field theory. Phase diagrams over a wide area of the parameter space are obtained by varying the interparticle interaction strength, geometric frustration strength, and temperature. Our results show that frustration and thermal fluctuations play a competing role against the interactions and in general favor a metallic phase without antiferromagnetic order. Due to their interplay, the system exhibits competition between antiferromagnetic insulator, antiferromagnetic metal, paramagnetic insulator, and paramagnetic metal phases in the intermediate-interaction regime. In the strong-interaction limit, which reduces to the Heisenberg model, our result is consistent with previous studies.
Major scientific accomplishments of Prof. Kun Huang
Authors: Xia Jianbai
Published: September 2019

The 100th anniversary of the birth of Prof. Kun Huang is in this year. Prof. Huang is a paragon of the older generation of Chinese scientists. He had made great achievements in solid state physics. After the founding of the People’s Republic of China, he returned to China immediately, and devoted himself to education. He and Prof. Xide Xie initiated the research of semiconductors in China, and established the solid state physics major at Peking University, which has trained a large number of talents for China. In 1977, he became the director of the Institute of Semiconductors of the Chinese Academy of Sciences. Led by Prof. Huang, together with Prof. Shouwu Wang, Prof. Lanying Lin and Prof. Shoujue Wang, the semiconductor institute independently overcomes many difficulties and created a group of critical devices which were on international embargo but urgently needed by China. Furthermore, he also made new contributions in the field of semiconductor superlattices. Under his leadership, the State Key Laboratory of Semiconductor Superlattices became one of the internationally leading laboratories. The following are the major scientific contributions of Prof. Kun Huang.
Lattice vibration and Raman scattering of two-dimensional van der Waals heterostructure
Authors: Cong Xin , Lin Miaoling , Tan Ping-Heng
Published: September 2019

Research on two-dimensional (2D) materials and related van der Waals heterostructures (vdWHs) is intense and remains one of the leading topics in condensed matter physics. Lattice vibrations or phonons of a vdWH provide rich information, such as lattice structure, phonon dispersion, electronic band structure and electron–phonon coupling. Here, we provide a mini review on the lattice vibrations in vdWHs probed by Raman spectroscopy. First, we introduced different kinds of vdWHs, including their structures, properties and potential applications. Second, we discussed interlayer and intralayer phonon in twist multilayer graphene and MoS2. The frequencies of interlayer and intralayer modes can be reproduced by linear chain model (LCM) and phonon folding induced by periodical moiré potentials, respectively. Then, we extended LCM to vdWHs formed by distinct 2D materials, such as MoS2/graphene and hBN/WS2 heterostructures. We further demonstrated how to calculate Raman intensity of interlayer modes in vdWHs by interlayer polarizability model.
Applications of Huang–Rhys theory in semiconductor optical spectroscopy
Authors: Zhang Yong
Published: September 2019

A brief review of Huang–Rhys theory and Albrechtos theory is provided, and their connection and applications are discussed. The former is a first order perturbative theory on optical transitions intended for applications such as absorption and emission involving localized defect or impurity centers, emphasizing lattice relaxation or mixing of vibrational states due to electron–phonon coupling. The coupling strength is described by the Huang–Rhys factor. The latter theory is a second order perturbative theory on optical transitions intended for Raman scattering, and can in-principle include electron–phonon coupling in both electronic states and vibrational states. These two theories can potentially be connected through the common effect of lattice relaxation – non-orthonormal vibrational states associated with different electronic states. Because of this perceived connection, the latter theory is often used to explain resonant Raman scattering of LO phonons in bulk semiconductors and further used to describe the size dependence of electron–phonon coupling or Huang–Rhys factor in semiconductor nanostructures. Specifically, the A term in Albrechtos theory is often invoked to describe the multi-LO-phonon resonant Raman peaks in both bulk and nanostructured semiconductors in the literature, due to the misconception that a free-exciton could have a strong lattice relaxation. Without lattice relaxation, the A term will give rise to Rayleigh or elastic scattering. Lattice relaxation is only significant for highly localized defect or impurity states, and should be practically zero for either single particle states or free exciton states in a bulk semiconductor or for confined states in a semiconductor nanostructure that is not extremely small.
Broadband polarized photodetector based on p-BP/n-ReS2 heterojunction
Authors: Zhu Wenkai , Wei Xia , Yan Faguang , Lv Quanshan , Hu Ce , Wang Kaiyou
Published: September 2019

Two-dimensional (2D) atomic crystals, such as graphene, black phosphorus (BP) and transition metal dichalcogenides (TMDCs) are attractive for use in optoelectronic devices, due to their unique crystal structures and optical absorption properties. In this study, we fabricated BP/ReS2 van der Waals (vdWs) heterojunction devices. The devices realized broadband photoresponse from visible to near infrared (NIR) (400–1800 nm) with stable and repeatable photoswitch characteristics, and the photoresponsivity reached 1.8 mA/W at 1550 nm. In addition, the polarization sensitive detection in the visible to NIR spectrum (532–1750 nm) was demonstrated, and the photodetector showed a highly polarization sensitive photocurrent with an anisotropy ratio as high as 6.44 at 1064 nm. Our study shows that van der Waals heterojunction is an effective way to realize the broadband polarization sensitive photodetection, which is of great significance to the realization and application of multi-functional devices based on 2D vdWs heterostructures.
Students’ Intuition Characteristics in Solve Mathematical Problem In Stage Planning
Authors: Arwanto  , Ketut Budayasa I , Teguh Budiarto Mega
Published: September 2019

This research is descriptive explorative with a qualitative approach, aims to know the characteristics of student intuition in making the mathematical problem-solving plan. Data collection methods triangulate data through tests,/and documentation. The subject of the research is a mathematics education student of the Muhammadiyah University of Cirebon. The population of the subjects was fifty students and then selected who had the initial ability of mathematics was twenty five students, after that selected one female student whose TPMM and IPK is medium and has good mathematical delivery. The results of this study indicate that the intuition of students in solving mathematical problems at the stage of understanding Polya problem: First, Subjec using intuition is self-evident intuition, that is, statement, representation, or interpretation is considered the subject right by itself, the subject feels no need to show/prove formally the truth of such statements, representations, or interpretations. Second, Subjects use certainty’s intrinsic intuition, ie the subject assumes a statement, its representation, or its interpretation, a certainty, no external support (formal or empirical to obtain it). Third, the subject uses intuition perseverance, ie the interpretation and the resulting representation of the subject tend to be difficult to change. It is proved by the tendency to not use something new beyond its mathematical comprehension. Fourth, Subject use extrapolative ness intuition, ie, subject to certain interpretations, decisions or conclusions based on insufficient information or data. It is proved that the subject is not intact in making problem-solving plans based on the Polya stage.