bluuebunny/crossref_metadata_2025 huggingface dataset:
Perineal Lacerations: A Retrospective Study in a Habitual-Risk Public Maternity
Authors: Domenighi Lauro Henrique Heinsch , Weinmann Angela Regina Maciel , Haeffner Leris Salete Bonfanti , Feltrin Marcelo Lorensi
Published: September 2021

Objective In around 85% of vaginal births, the parturients undergo perineal lacerations and/or episiotomy. The present study aimed to determine the incidence of lacerations and episiotomies among parturients in 2018 in a habitual-risk public maternity hospital in southern Brazil, and to determine the risk and protective factors for such events.

Methodology A retrospective cross-sectional study. Data were obtained from medical records and analyzed using the Stata software. Univariate and multivariate logistic regressions were performed. Values of p < 0.05 were considered significant.

Results In 2018, there were 525 vaginal births, 27.8% of which were attended by obstetricians, 70.7% by obstetric nurses, and 1.5% evolved without assistance. Overall, 55.2% of the parturients had some degree of laceration. The professional who attended the birth was a significant variable: a greater number of first- and second-degree lacerations, as well as more severe cases, occurred in births attended by nurses (odds ratio [OR]: 2,95; 95% confidence interval [95%CI]: 1,74 to 5,03). Positions at birth that did not enable perineal protection techniques (expulsive period with the “hands-off” method), when analyzed in isolation, determined the risk; however, in the final regression model, this relationship was not confirmed. Although reported in the literature, there were no associations between the occurrence of laceration and age, skin color, or birth weight. In 24% of the births, episiotomy was performed, and doctors performed 63.5% of them.

Conclusion Births attended by nurses resulted in an increased risk of perineal lacerations, of varying degrees. In turn, those assisted by physicians had a higher occurrence of episiotomy.
Laser Doppler Measurements of Systolic Blood Pressure on the First and Second Toe in Patients with Peripheral Arterial Disease
Authors: Rosfors Stefan , Modin Agnes , Petrini Johan
Published: September 2021

Laser Doppler was used to measure toe blood pressure (TBP) in 40 consecutive patients with various degree of peripheral arterial disease. The aim of this methodological study was to increase the usefulness of TBP by exploring the interchangeability between TBP from the first and second toe and by investigating daily routine reproducibility and measurement variability. According to our study design pressure values were based on three measurements that were averaged. At simultaneous measurements, TBP of the first toe was 71 mm Hg (standard deviation [SD] 25) compared with 70 mm Hg (SD 25) on the second toe. The correlation (r) between first and second toe pressure measurements was 0.84 and intraclass correlation coefficient (ICC) was 0.84. The difference between TBP on the first and second toe was not related to gender, diabetes, or magnitude of the pressures. Repeated TBP measurements of the right first toe after disconnection of cuffs, 5 to 10 minutes rest, and reconnection of cuffs had a coefficient of variation (CV) of 9% and an ICC of 0.93. CV for toe-brachial index (TBI) was 8%. Our results show that measurements of TBP from the second toe to a large extent are interchangeable with those assessed from the first toe and can be used in clinical situations where measurements from the first toe are not feasible. Flow detection with three averaged laser Doppler measurements generates TBP and TBI with low variability.
Concordance Between Clinical and Laboratory Diagnosis of Abnormal Vaginal Discharge in Chilean Women
Authors: Melo Angélica , Ossa Ximena , Fetis Giselle , Lazo Lorena , Bustos Luis , Fonseca-Salamanca Flery
Published: September 2021

Objective To determine the concordance between the clinical diagnosis of women with abnormal vaginal discharge (AVD) and laboratory results using molecular detection and observation of the vaginal microbiota.

Methods Cross-sectional study conducted in 2018 in Temuco, Chile. A total of 25 midwives from 12 health centers participated. A total of 125 women > 18 years old, volunteers, were recruited. The sample of the posterior vaginal fornix was obtained by speculoscopy. Characteristics of the discharge and of the external and internal genitalia were observed. Gram staining was used to observe vaginal microbiota, blastoconidia and pseudohyphae, and polymerase chain reaction was used for the detection of Trichomonas vaginalis and Candida albicans. The Cohen kappa coefficient was used in the concordance analysis.

Results Out of a total of 125 women with AVD, 85.6% consulted spontaneously and 14.4% were diagnosed clinically during a routine check-up. Absolute concordance was significant (p = 0.0012), with an agreement of 13.6%. The relative concordance was significant, but fair for bacterial vaginosis (Kappa = 0.21; p = 0.003) and candidiasis (Kappa = 0.22; p = 0.001), and slight for trichomoniasis (Kappa = 0.14; p = 0.009). The percentage of coincidence of the diagnoses (single or mixed) by laboratory and midwives was: bacterial vaginosis 63.2% (12/19), candidiasis 36.5% (27/74), and trichomoniasis 12.5% (4/32). There was 20% coinfection. A total of 36% of the clinical diagnoses of AVD had negative laboratory tests.

Conclusion The vulvovaginitis conditions candidiasis and trichomoniasis appear to be overdiagnosed, and bacterial vaginosis appears to be underdiagnosed by the clinical diagnosis when compared with the laboratory diagnosis. The low concordance obtained shows the importance of complementing the clinical diagnosis with a laboratory study of AVD, particularly in women with failed treatments and/or coinfections with unspecific and varying signs and symptoms.
Prophylactic Efficacy of Tibial Plateau Levelling Osteotomy for a Canine Model with Experimentally Induced Degeneration of the Cranial Cruciate Ligament
Authors: Shimada Masakazu , Kanno Nobuo , Ichinohe Tom , Suzuki Shuji , Harada Yasuji , Hara Yasushi
Published: September 2021

Objective The aim of this study was to clarify the histological effects of tibial plateau levelling osteotomy on cranial cruciate ligament degeneration induced by excessive tibial plateau angle.

Study Design Five female Beagles were used to bilaterally create excessive tibial plateau angle models surgically. A second tibial plateau levelling osteotomy was performed 11 months after the first surgery on the right stifle (tibial plateau levelling osteotomy group), and a sham operation that did not change the tibial plateau angle was performed on the left stifle (excessive tibial plateau angle group). At 6 months after the second surgery, the dogs were euthanatized. The cranial cruciate ligament was stained with haematoxylin–eosin to assess the cell density, Alcian-Blue to assess proteoglycans and Elastica-Eosin to assess elastic fibres, and immunohistochemically stained to assess type I (COL1) and type II collagen and SRY-type HMG box 9 (SOX9) expression.

Results In each group, the cranial cruciate ligament degeneration, especially on the tibial side, including the presence of Alcian-Blue- and Elastica-Eosin-positive regions, decreased in COL1-positive regions, and enhancement of SOX9 expression was observed. Besides, compared with the tibial plateau levelling osteotomy group, the excessive tibial plateau angle group showed increases in Alcian-Blue- and Elastica-Eosin-positive regions and a decrease in the COL1-positive regions.

Conclusion The results suggested that excessive tibial plateau angle-induced cranial cruciate ligament degeneration can be suppressed by reducing the biomechanical load on the cranial cruciate ligament by performing tibial plateau levelling osteotomy.
Cochlear Model for the Evaluation of MRI Sequences and Cochlear Implant Electrode Pattern at 3T
Authors: Scholtz Lars Uwe , Riemann Conrad , Gehl Hans Björn , Sudhoff Holger , Todt Ingo
Published: September 2021

Introduction Cochlear implant (CI) magnets and surgical techniques (e.g., positioning) have made an impact on the relationship between CI and magnetic resonance imaging (MRI) by solving the problem of pain and artifact. Recent investigations displayed the possibility to evaluate the CI electrode position by MRI in vivo. However, further improved perceptual quality is needed to allow an improved evaluation of the electrode.

Aims The aim of this study was to assess a cochlear model for the examination of CI electrode pattern and MRI sequences in vitro.

Materials and Methods We investigated CI electrodes in a fluid-filled three-dimensional artificial scala tympani model combined with a fluid package in a 3T MRI scanner. Different high-resolution T2 sequences (0.6–0.2 mm voxel size) were used for the visual electrode pattern evaluation for finding an optimized sequence.

Results Artificial models can be used to evaluate MRI characteristics of CI electrodes. In our scanner configuration, a 0.3 mm voxel and 0.9 mm slice thickness sequence showed the best compromise between resolution and scanning time.

Conclusion and Significance MRI model-based testing can be performed in vitro to evaluate CI electrodes’ pattern and to optimize sequences. An MRI model is a tool for in vitro testing of MRI sequences and might help for future in vivo applications.
Theoretical insights for CoNxC4-x-graphene (x = 0–4) materials as high performance low-cost electrocatalysts for oxygen reduction reactions
Authors: Li Lubing , Zhang Lei , Su Jinzhan , Li Mingtao
Published: September 2021

Transition metal-doped two-dimension carbon matrices have attracted particular interest as oxygen reduction reaction (ORR) catalysts because of their low-cost, good conductivity of electricity, and promising applications in fuel cells and metal-air batteries. Herein, a density functional theory study is performed on the CoNxC4-x (x = 0–4) embedded graphene to investigate the effect of N atoms doping number and doping configurations. The calculated formation energy and average bond length of Co–C/N drop off with the increase in N atoms of the CoNxC4-x graphene system. The most stable adsorption configurations and the relevant adsorption free energies of key ORR intermediates on Co–N sites toward the CoNxC4-x graphene system are obtained, indicating that N doping levels and doping configurations have a regular influence on this system. On this basis, scaling relations can be obtained among the adsorption free energies of *OH, *OOH, and *O. The volcano plot of ORR theoretical overpotential (ηth) using ΔG*OH−ΔG*O as a descriptor was further established, which revealed that ηth is influenced by the adsorption mode and the free energy change in the active site. For all studied systems, the ORR substeps are all downhill at zero potential from the plotted free energy diagrams. The density of states is employed to further illustrate that the hybridization between the Co atom and the O atom is a deterring factor on electrocatalyst activity. These calculations reveal the influence of nitrogen atom doping in Co–N-graphene catalysts and afterward point a direction for designing high-performance non-precious metal ORR electrocatalysts.
Fabrication of spectroscopic characterization techniques using an optical fiber-based spectrometer
Authors: S Satyanarayana Reddy , H. S Lokesha , K. R Nagabhushana
Published: September 2021

High-sensitive spectroscopy instruments have been developed to measure thermoluminescence emission (TLE), diffuse reflectance, and photoluminescence (PL). The key features of these instruments are low cost, high resolution, and compact size. For TLE measurement, A Kanthal resistive heating strip with a linear heating rate and Ocean Optics spectra suite software were used. Thermally stimulated emission of light was recorded using a USB4000+ES spectrophotometer in the UV-Vis region. In the TLE spectra, intensity vs wavelength was recorded as a function of temperature. In the high instance TLE spectrum of Al2O3, Tm3+ measured at 458 K shows peaks at 298, 355, 394, 466, 526, 658, 672, 696, and 713 nm. The UV-Vis DRS spectrum of the ZnO powder sample was measured at room temperature in the wavelength range 230–750 nm. The optical bandgap of ZnO was determined using Kubelka–Munk theory and found to be 3.22 eV. In the PL setup, a xenon lamp as the excitation source, direct-attach cuvette holder, visible light filter, IR filter, and adjustable UV bandpass linear variable filter were used. The excitation wavelength was fixed using a filter, and the emission spectra of samples were recorded. In the PL emission spectrum of Al2O3, Tb3+ shows bands at 382, 420, 438, 462, 487, 543, 586, and 623 nm, which are characteristic of Tb3+ ions. The obtained PL results are compared with data acquired using the Hitachi (F-2700) fluorescence spectrometer. This cost-effective spectroscopy instrument will be beneficial in materials science research in order to investigate the optical properties of the materials by study of TLE, PL, and diffuse reflectance.
In situ electrical conductivity measurements of porous water-containing rock materials under high temperature and high pressure conditions in an autoclave
Authors: Shan Shuangming , Xiao Chaoyi , Li Heping , Xu Liping , Lin Sen , Li Shengbin
Published: September 2021

This study presents a method for measuring the electrical conductivity of porous rock materials in situ under a shallow Earth crust environment simulated according to temperature, confining pressure, and liquid water saturation in a high-temperature autoclave. The sample was first encased within a poly tetra fluoroethylene container with two Pt wires leading out and was then placed into the high-temperature autoclave. The lead wires were connected to an external measurement system after passing through the autoclave sealing plug. The electrical conductivity of sandstone was measured under different temperatures (30, 60, 90, 120, 150 °C), liquid water saturation levels (36%, 51%, 100%), and 2 MPa by using this method. The electrical conductivity of the sandstone samples increased with increasing temperature and also increased as the level of water saturation increased. All the results agreed well with the Arrhenius relationship, Archie’s law, and previous experimental study. This method can be used to measure other kinds of porous water-containing rocks, and the results can be applied in geothermal/oil research.
Development of a flexure-based nano-actuator for high-frequency high-resolution directional sensing with atomic force microscopy
Authors: Payam Amir F. , Piantanida Luca , Voïtchovsky Kislon
Published: September 2021

Scanning probe microscopies typically rely on the high-precision positioning of a nanoscale probe in order to gain local information about the properties of a sample. At a given location, the probe is used to interrogate a minute region of the sample, often relying on dynamical sensing for improved accuracy. This is the case for most force-based measurements in atomic force microscopy (AFM) where sensing occurs with a tip oscillating vertically, typically in the kHz to MHz frequency regime. While this approach is ideal for many applications, restricting dynamical sensing to only one direction (vertical) can become a serious limitation when aiming to quantify the properties of inherently three-dimensional systems, such as a liquid near a wall. Here, we present the design, fabrication, and calibration of a miniature high-speed scanner able to apply controlled fast and directional in-plane vibrations with sub-nanometer precision. The scanner has a resonance frequency of ∼35 kHz and is used in conjunction with a traditional AFM to augment the measurement capabilities. We illustrate its capabilities at a solid–liquid interface where we use it to quantify the preferred lateral flow direction of the liquid around every sample location. The AFM can simultaneously acquire high-resolution images of the interface, which can be superimposed with the directional measurements. Examples of sub-nanometer measurements conducted with the new scanner are also presented.
Dust-acoustic waves in weakly coupled (gaseous) cryogenic dusty plasma
Authors: Trukhachev F. M. , Boltnev R. E. , Alekseevskaya A. A. , Vasiliev M. M. , Petrov O. F.
Published: September 2021

Experimental results on dust-acoustic wave study in a weakly coupled cryogenic dusty plasma within the DC glow discharge are discussed. Analysis of dust particle trajectories, their velocity distributions, and the pair correlation function allows us to conclude that the 3D dusty plasma structure studied at T = 83 K was most likely a gaseous structure.
Simulating the collision of a moving droplet against a moving particle: Impact of Bond number, wettability, size ratio, and eccentricity
Authors: Wu Guoqiang , Chen Sheng
Published: September 2021

This paper presents a direct numerical simulation for the collision of a moving droplet against a moving particle under gravity, based on the pseudopotential lattice Boltzmann model. The effects of Bond number (Bo), particle surface wettability, particle–droplet size ratio (α), and eccentricity ratio (B) on the collision processes are investigated comprehensively. Six findings are reported and analyzed for the first time: (1) an agglomeration process is observed for the collision with a very small Bond number. During the agglomeration process, the vertical velocity of the particle will experience a deceleration, and the deceleration will become weak against the increase in the Bond number. (2) The wettability will influence the variation of the vertical velocity of the moving particle remarkably. The vertical velocity of the neutral particle is nearly linearly accelerated, but the lyophilic particle experiences an obvious deceleration. In addition, the velocity history of the lyophobic particle shows a nonlinear acceleration. (3) The increase in the particle–droplet size ratio will postpone the emergence of the deceleration process. Therefore, the appearance of the peak vertical velocity is delayed against the increase in the particle–droplet size ratio. (4) For different eccentricity ratios, the differences of the velocities (e.g., the horizontal, vertical, and angular velocity) are very small in the beginning of collision, while a big difference appears with time elapses. Besides, the variation of velocities becomes very obvious. (5) There is a critical value for B, where the horizontal velocity, vertical velocity, and angular velocity of the particle investigated in the work all will reach their maximum values. (6) A rebound regime is observed when a moving droplet collides vertically against a moving particle. In the available literature, a rebound regime was observed only when a droplet colliding against a fixed particle, but never for a vertically moving particle. The present research reveals when a rebound process will appear. The finding here may shed some light on the mechanism of the collision of a moving droplet against a moving particle.
Viscoelastic response of impact process on dense suspensions
Authors: Pradipto  , Hayakawa Hisao
Published: September 2021

We numerically study impact processes on dense suspensions using the lattice Boltzmann method to elucidate the connection between the elastic rebound of an impactor and relations among the impact speed u0, maximum force acting on the impactor Fmax, and elapsed time tmax to reach Fmax. We find that tmax emerges in the early stage of the impact, while the rebound process takes place in the late stage. We find a crossover of Fmax from the u0 independent regime for low u0 to a power law regime satisfying Fmax∝u0α with α≈1.5 for high u0. Similarly, tmax satisfies tmax∝u0β with β≈−0.5 for high u0. Both power-law relations for Fmax and tmax vs u0 for high u0 are independent of the system size, but the rebound phenomenon strongly depends on the depth of the container for suspensions. Thus, we indicate that the rebound phenomenon is not directly related to the relations among u0, Fmax and tmax. We propose a floating + force chain model, where the rebound process is caused by an elastic term that is proportional to the number of the connected force chains from the impactor to the bottom plate. On the other hand, there are no elastic contributions in the relations for Fmax and tmax against u0 because of the absence of percolated force chains in the early stage. This phenomenology predicts Fmax∝u03/2 and tmax∝u0−1/2 for high u0 and also recovers the behavior of the impactor quantitatively even if there is the rebound process.
Tailoring broadband Kerr soliton microcombs via post-fabrication tuning of the geometric dispersion
Authors: Moille Gregory , Westly Daron , Orji Ndubuisi George , Srinivasan Kartik
Published: September 2021

Geometric dispersion in integrated microresonators plays a major role in nonlinear optics applications, especially at short wavelengths, to compensate the natural material normal dispersion. Tailoring of geometric confinement allows for anomalous dispersion, which, in particular, enables the formation of microcombs that can be tuned into the dissipative Kerr soliton (DKS) regime. Due to processes like soliton-induced dispersive wave generation, broadband DKS combs are particularly sensitive to higher-order dispersion, which, in turn, is sensitive to the ring dimensions at the nanometer-level. For microrings exhibiting a rectangular cross section, the ring width and thickness are the two main control parameters to achieve the targeted dispersion. The former can be easily varied through parameter variation within the lithography mask, yet the latter is defined by the film thickness during growth of the starting material stack and can show a significant variation (few percent of the total thickness) over a single wafer. In this Letter, we demonstrate that controlled dry-etching allows for fine tuning of the device layer (silicon nitride) thickness at the wafer level, allowing multi-project wafers targeting different wavelength bands and post-fabrication trimming in air-clad ring devices. We demonstrate that such dry etching does not significantly affect either the silicon nitride surface roughness or the optical quality of the devices, thereby enabling fine tuning of the dispersion and the spectral shape of the resulting DKS states.
Symmetry-breaking bifurcations in two-dimensional square vortex flows
Authors: Suri Balachandra
Published: September 2021

We present a theoretical study of spatial symmetries and bifurcations in a laterally bounded two-dimensional flow composed of approximately square vortices. The numerical setting simulates a laboratory experiment wherein a shallow electrolyte layer is driven by a plane-parallel force that is nearly sinusoidal in both extended directions. Choosing an integer or half-integer number of forcing wavelengths along each direction, we generate square vortex flows invariant under different spatial symmetries. We then map out the sequence of symmetry-breaking bifurcations leading to the formation of fully asymmetric flows. Our analysis reveals a gallery of pitchfork and Hopf bifurcations, both supercritical and subcritical in nature, resulting in either steady or time-dependent asymmetric flows. Furthermore, we demonstrate that different types of flows (steady, periodic, pre-periodic, or quasi-periodic), at times with twofold multiplicity, emerge as a result of symmetry-breaking bifurcations. Our results also provide new theoretical insights into previous experimental observations in quasi-two-dimensional square vortex flows.
Effective medium model for a suspension of active swimmers
Authors: Dhar A. , Burada P. S. , Raja Sekhar G. P.
Published: September 2021

Several active organisms in nature tend to reside as a community in viscous fluid media. We analyze the variation of the swimming characteristics of an active swimmer present in a dilute and disperse suspension, modeled as an effective Brinkman medium. This idealized representation of a collection of active swimmers allows one to distinguish the impact of the interior domain available to an individual swimmer as well as the contribution of its neighbors. Darcy's law along with an analytical solution enable the effective resistivity to be predicted as a function of the volume fraction, which is in close agreement with the well-known Carman–Kozeny equation. This facilitates the successive analysis of the propulsion speed, power dissipation, and swimming efficiency of the targeted swimmer—which are decisive in nutrient transport and uptake or reproduction in a collective environment—as a function of the volume fraction. A stress-jump condition is also imposed across a cell to indicate the mean effective force due to nearby swimmers. For suitable values of this stress-jump coefficient, the relative increase in migration velocity and swimming efficiency is noticeably higher at an optimum occupancy. To highlight the rheological characteristics, we have analyzed the effective viscosity of the active suspension, which varies distinctively from a random suspension and alludes to self-assembly.
A multiconfiguration pair-density functional theory-based approach to molecular junctions
Authors: Sand Andrew M. , Malme Justin T. , Hoy Erik P.
Published: September 2021

Due to their small size and unique properties, single-molecule electronics have long seen research interest from experimentalists and theoreticians alike. From a theoretical standpoint, modeling these systems using electronic structure theory can be difficult due to the importance of electron correlation in the determination of molecular properties, and this electron correlation can be computationally expensive to consider, particularly multiconfigurational correlation energy. In this work, we develop a new approach for the study of single-molecule electronic systems, denoted NEGF-MCPDFT, which combines multiconfiguration pair-density functional theory (MCPDFT) with the non-equilibrium Green’s function formalism (NEGF). The use of MCPDFT with NEGF allows for the efficient inclusion of both static and dynamic electron correlations in the description of the junction’s electronic structure. Complete active space self-consistent field wave functions are used as references in the MCPDFT calculation, and as with any active space method, effort must be made to determine the proper orbital character to include in the active space. We perform conductance and transmission calculations on a series of alkanes (predominantly single-configurational character) and benzyne (multiconfigurational character), exploring the role that active space selection has on the computed results. For the alkane junctions explored (where dynamic electron correlation dominates), the MCPDFT-NEGF results agree well with the DFT-NEGF results. For the benzyne junction (which has a significant static correlation), we see clear differences in the MCPDFT-NEGF and DFT-NEGF results and evidence that NEGF-MCPDFT is capturing additional electron correlation effects beyond those provided by the Perdew–Burke–Ernzerhof functional.
Fractal permeability model for a complex tortuous fracture network
Authors: Xia Binwei , Luo Yafei , Hu Huarui , Wu Mingyang
Published: September 2021

The complex fracture network in unconventional oil and gas reservoirs is the main channel for the fluid flow, and effective prediction of fracture network permeability is the basis for further accurate assessment of oil and gas productivity. On the basis of the traditional parallel-plate cube law, we introduce the tortuosity fractal dimension DTf to characterize the tortuosity of fractures. Then, combined with fractal theory, a permeability model is derived for a complex tortuous discrete fracture network (DFN). A pixel probability decomposition algorithm is used to generate ten random DFNs that conform to the fractal scale relationship, and the effectiveness of the proposed model is verified by numerical simulation. The fracture geometry parameters are further analyzed and their effect on permeability discussed. The results show that the permeability K of a fracture network increases with an increase in porosity ϕ (0.117–0.292), fractal dimension Df (1.635–1.824), maximum fracture length lmax (3.337–7.472 m), and proportionality coefficient β (0.00108–0.0164), but decreases with the increasing tortuosity fractal dimension DTf (1.0018–1.0196) and fracture dip angle θ (10°–80°). Among these parameters, Df, DTf, and β have the greatest influence on the permeability of the fracture network, followed by θ, lmax, and ϕ.
Multi-bifurcation behaviors of stability regimes in a centrally staged swirl burner
Authors: Wang Xinyao , Han Xiao , Song Heng , Yang Dong , Sung Chih-Jen
Published: September 2021

Multi-bifurcation behaviors of staged swirl flames fueled with methane at atmospheric pressure are experimentally investigated by varying the global equivalence ratio (ϕglo). Based on the characteristics of measured pressure oscillations and the associated results of phase space reconstruction, recurrence plots, and synchrosqueezing-transform-based time-frequency analysis, the multi-bifurcation behaviors of this thermoacoustic system with four different stability regimes have been identified. With incremental increase in ϕglo from 0.55 to 0.79, these four stability regimes follow the sequence of a quiet mode (Regime I), the first limit cycle with moderate oscillations (Regime II), an intermediate state with intermittent bursts of multi-modes (Regime III), and the second limit cycle with much stronger oscillations (Regime IV). The flame dynamics in Regimes II and IV undergoing limit cycle oscillations are compared. The flame structure in Regime II displays an attached twin-flame structure, the same as that observed in Regime I. However, a large-scale periodic convective motion is found in Regime IV, which is identified to be the main thermoacoustic driving factor in the local Rayleigh index maps. Further experiments are carried out by continuously increasing ϕglo to examine the synchrosqueezing-transform spectra of transient processes during the two bifurcations. The present investigation is instrumental in obtaining a fundamental understanding of nonlinearity and multi-bifurcation of thermoacoustic instabilities in centrally staged swirl combustors, which is vital in guiding the early stage design and developing detection/control strategies in practical low-emission combustion systems.
Structural and transport properties of Y1-x(Dy)xPdBi (0 ≤ x ≤ 1) topological semi-metallic thin films
Authors: Bhardwaj Vishal , Banerjee Niladri , Chatterjee Ratnamala
Published: September 2021

We report the effect of 4f electron doping on structural, electrical, and magneto-transport properties of Dy doped half Heusler Y1-x(Dy)xPdBi (x = 0, 0.2, 0.5, and 1) thin films grown by pulsed laser deposition. The electrical transport measurements show a typical semi-metallic behavior in the temperature range of 3 K ≤ T ≤ 300 K and a sharp drop in resistivity at low temperatures (<3 K) for all the samples. Magneto-transport measurements and Shubnikov de-Hass oscillations at high magnetic fields demonstrate that for these topologically non-trivial samples, Dy doping induced variation of spin–orbit coupling strength and lattice density plays an active role in modifying the Fermi surface, carrier concentration, and the effective electron mass of massless carriers. There is a uniform suppression of the onset of superconductivity-like phenomena with increased Dy doping, which is possibly related to the increasing local exchange field arising from the 4f electrons in Dy. Our results indicate that we can tune various band structure parameters of YPdBi by f electron doping, and strained thin films of Y1-x(Dy)xPdBi show surface dominated relativistic carrier transport at low temperatures.
Improved ferroelectricity in Hf0.5Zr0.5O2 by inserting an upper HfOxNy interfacial layer
Authors: Kim Beom Yong , Kim Se Hyun , Park Hyeon Woo , Lee Yong Bin , Lee Suk Hyun , Oh Minsik , Ryoo Seung Kyu , Lee In Soo , Byun Seungyong , Shim Doosup , Park Min Hyuk , Hwang Cheol Seong
Published: September 2021

In this study, the influence of the HfOxNy interfacial layer (IL), interposed between the atomic layer deposited ferroelectric (FE) Hf0.5Zr0.5O2 thin film and TiN top electrode, on the FE properties of such a film was examined. The HfOxNy IL decreased the relative proportion of the non-FE monoclinic phase, possibly due to the N-doping effect. Furthermore, the oxidation of the TiN top electrode was also suppressed by the sacrificial oxidation of the HfOxNy IL during the rapid thermal process. As a result, the double remanent polarization of a Hf0.5Zr0.5O2 thin film could be enhanced from 40.2 to 48.2 μC/cm2 by the positive-up-negative-down test, and its degradation by fatigue during the endurance test can also be decreased. This result demonstrates the significance of interfacial engineering to optimize the FE properties of Hf0.5Zr0.5O2 films.
Molecular characterization of a complex of apoptosis-inducing factor 1 with cytochrome c oxidase of the mitochondrial respiratory chain
Authors: Hevler Johannes F. , Zenezeni Chiozzi Riccardo , Cabrera-Orefice Alfredo , Brandt Ulrich , Arnold Susanne , Heck Albert J. R.
Published: September 2021

Significance

Apoptosis-inducing factor 1 (AIFM1) resides within the intermembrane space of mitochondria and upon programmed cell death was found to induce chromatin condensation and DNA fragmentation. While the apoptosis-related role of AIFM1 is well understood, recent findings pointed to additional, not well-characterized functional roles of AIFM1 in oxidative phosphorylation. Using cross-linking mass spectrometry and complexome profiling, we uncover that a substantial amount of dimeric AIFM1 is engaged with ∼10% of monomeric cytochromecoxidase (COX). Further structural modeling and restraint-driven docking structurally characterize a COX-AIFM12complex, not only highlighting how AIFM1 might be N-terminally inserted into the inner mitochondrial membrane but also providing clues on potential functional implications including an involvement in promoting apoptosis.
Design of proteasome inhibitors with oral efficacy in vivo against
Plasmodium falciparum
and selectivity over the human proteasome
Authors: Xie Stanley C. , Metcalfe Riley D. , Mizutani Hirotake , Puhalovich Tanya , Hanssen Eric , Morton Craig J. , Du Yawei , Dogovski Con , Huang Shih-Chung , Ciavarri Jeffrey , Hales Paul , Griffin Robert J. , Cohen Lawrence H. , Chuang Bei-Ching , Wittlin Sergio , Deni Ioanna , Yeo Tomas , Ward Kurt E. , Barry Daniel C. , Liu Boyin , Gillett David L. , Crespo-Fernandez Benigno F. , Ottilie Sabine , Mittal Nimisha , Churchyard Alisje , Ferguson Daniel , Aguiar Anna Caroline C. , Guido Rafael V. C. , Baum Jake , Hanson Kirsten K. , Winzeler Elizabeth A. , Gamo Francisco-Javier , Fidock David A. , Baud Delphine , Parker Michael W. , Brand Stephen , Dick Lawrence R. , Griffin Michael D. W. , Gould Alexandra E. , Tilley Leann
Published: September 2021

Significance

Here, we describe inhibitors of the
Plasmodium
proteasome, an enzymatic complex that malaria parasites rely on to degrade proteins. Starting from inhibitors developed to treat cancer, derivatives were designed and synthesized with the aim of increasing potency against the
Plasmodium
proteasome and decreasing activity against the human enzyme. Biochemical and cellular assays identified compounds that exhibit selectivity and potency, both in vitro and in vivo, at different stages of the parasite’s lifecycle. Cryo-electron microscopy revealed that the inhibitors bind in a hydrophobic pocket that is structurally different in the human proteasome—underpinning their selectivity. The work will help develop antimalarial therapeutics, which are desperately needed to treat a disease that kills nearly half a million people annually.
Task adapted reconstruction for inverse problems
Authors: Adler Jonas , Lunz Sebastian , Verdier Olivier , Schönlieb Carola-Bibiane , Öktem Ozan
Published: September 2021

The paper considers the problem of performing a post-processing task defined on a model parameter that is only observed indirectly through noisy data in an ill-posed inverse problem. A key aspect is to formalize the steps of reconstruction and post-processing as appropriate estimators (non-randomized decision rules) in statistical estimation problems. The implementation makes use of (deep) neural networks to provide a differentiable parametrization of the family of estimators for both steps. These networks are combined and jointly trained against suitable supervised training data in order to minimize a joint differentiable loss function, resulting in an end-to-end task adapted reconstruction method. The suggested framework is generic, yet adaptable, with a plug-and-play structure for adjusting both the inverse problem and the post-processing task at hand. More precisely, the data model (forward operator and statistical model of the noise) associated with the inverse problem is exchangeable, e.g., by using neural network architecture given by a learned iterative method. Furthermore, any post-processing that can be encoded as a trainable neural network can be used. The approach is demonstrated on joint tomographic image reconstruction, classification and joint tomographic image reconstruction segmentation.
A new ternary pentagonal monolayer based on Bi with large intrinsic Dzyaloshinskii–Moriya interaction
Authors: Debbichi M , Saïd H , Garbouj H , El Hog S , An Dinh Van
Published: September 2021

We systematically investigate the structural, electronic, and magnetic properties of a new pentagonal CoBiS monolayer using first-principles and Monte Carlo simulations. We find that Penta-CoBiS is stable mechanically, dynamically, and thermally and is an antiferromagnetic semiconductor with an indirect band gap of 0.5 eV with HSE functional. In addition, the band-gap increased by applying in-plane biaxial strain. We further show that this monolayer has an in-plane easy axis and possesses large intrinsic Dzyaloshinskii–Moriya interaction because of the broken inversion symmetry, and strong spin–orbit coupling originated from the Bi atoms. Moreover, the Néel temperature is also predicted using Monte Carlo simulations. An out-of-plane magnetic field B is then applied to compensate the in-plane anisotropy. It is found that for B = 1.72 T the spins are fully polarized to the out-of-plane direction. Our results demonstrate that Penta-CoBiS monolayer may find numerous applications in flexible spintronics and electronics.
Electrochemical methods for neural interface electrodes
Authors: Weltin Andreas , Kieninger Jochen
Published: September 2021

Objective. Neural interfaces often rely on charge transfer processes between electrodes and the tissue or electrolyte. Electrochemical processes are at the core of electrode function and, therefore, the key to neural interface stability, electrode performance characterization, and utilization of electrodes as chemical sensors. Electrochemical techniques offer a variety of options to investigate the charge transfer and electrocatalytic properties of electrodes. Approach. In this tutorial, we present various experiments to illustrate the power of electrochemical methods, serve as a reference and guideline, and stimulate deeper understanding of the subject. Main results. As a basis for the following experiments, we discuss the platinum cyclic voltammogram and focus on understanding surface processes and roughness determination. We highlight the importance of appropriate instrumentation using potentiostats and how strongly it can influence results. We then discuss a number of potential-controlled and current-controlled methods for electrode characterization, including chronocoulometry, chronoamperometry, (active) potentiometry, and chronopotentiometry. They illustrate charge transfer caused by both electrode surface processes and the presence of redox-active species, such as dissolved oxygen and hydrogen, or hydrogen peroxide. We also discuss the electrode potential with respect to a reference electrode under various conditions and how it affects its electrochemical properties like surface state, catalytic properties and capability to transfer charge. Significance. Electrochemical methods are still underutilized in neural engineering, and valuable information is therefore often not accessed. Many studies on electrode characterization would benefit from a more consistent and target-oriented electrochemical methodology and instrumentation. That ranges from the investigation of new materials and processes, over electrode performance assessment to the development of more long-term stable and biocompatible neural interfaces. Ultimately, standardization, consistency and comparability will play a key role in the translation of microtechnology into biomedical and clinical applications.
Influence of Waste Engine Oil Addition on the Properties of Natural Asphalt
Authors: Mahmood Bashar Abdulazeez
Published: September 2021

Disposal of waste engine oil (WEO) from vehicles is one of the significant problems that should be solved. One of the possible solution to this problem is to recycle WEOs in effective way. Therefore, in the current research, the WEO from the maintenance workshops of vehicles (in particular cars’ type) were used as an additive material (filler) to enhance the physical and chemical properties of local natural asphalt from Heet city-Al Anbar governorate. Different weight ratios 0%, 2 %, 4%, 6%, 8% were used to investigate their effect on the improvement of natural asphalt.

To study the achieved improvement, the properties of natural asphalt before and after the addition have been studied by conducting physical and chemical measurements such as penetration, viscosity, degree of flicker, solubility, and ductility. The chemical tests are also conducted such as Infrared spectroscopy and ultraviolet spectroscopy. This study proved that it is possible to get rid of polluting wastes such as oil waste which are harmful to the environment and can be recycled as a useful material in improving the properties of natural asphalt to be used for flattening purposes according to Iraqi specifications (1196-88) of the first type and the international standards (ASTM D312 type A). The chemical composition of asphalt extracted from the springs before addition is very similar to the model in which the oil is added being hydrocarbons, which indicates that no chemical reaction occurred but rather a process of mixing the components through a spectral survey in the ultraviolet and infrared regions where the same beams appeared chemical bonds and transitions, with only different density.
Preparation and Investigation of some Physical Properties and Photocatalytic Activity of a co-Catalyst CoO-V2O5
Authors: Idrees H. , Halbus Ahmed F. , Athab Zahraa H. , Saddam Nahlah Salman , Kahdum Salih H. , Atiyah Abbas J.
Published: September 2021

The current work involves preparation of neat vanadium oxide and cobalt oxide. Likewise, various percentage from their mixed forms were prepared in various ratios: 25%, 50%, 75% and 100% from CoO were precipitated with fixed weight of V2O5 2.0 g. In addition, the above percentage from V2O5 were precipitated with fixed weight of CoO, 2.0 g. The individual metal oxides and their mixtures with various ratios were prepared from the solution of sulphate and nitrate of both metals respectively by co-precipitation process by adding sodium carbonate. All metals carbonates transfer to corresponding oxides by calcification at 773 K. Spectroscopic studies for metal oxides and their mixtures with various ratios using X-rays diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Some of physical properties of these oxides and their mixtures were studies such as pore size, density, porosity and electrical conductivity. The activity of these materials were investigated by following photocatalytic oxidation of 1-octanol over a suspension of these materials. The obtained results showed that photocaatalytic oxidation of alcohol was achieved when using each of catalyst, light, air and 1-octanol.
Azo Dyes on the ligand(5-MeTAQ) Thin Films for Dye Sensitized Solar Cells Applications
Authors: kadam Zeina mohammed , Jeber Raheem Abed , Ali Alaa Hussein
Published: September 2021

This Include search the preparation of a new ligand from heterogeneous azo organic derivatives derived from Thiazolyl ligand (5-MeTAQ) and the identification of ligand (5-MeTAQ) were identification and analyzed by using 1H-NMR, mass spectrum, XRD SEM and EDX. Thin films of ligand dye prepared of concentration of (0.05,0.1,0.3) M membrane pure and doped of 10% hexaferrite (SrFe12O19) of concentration (0.05M) was prepared of thin films with thikness (1000 ±15) nm the preparation of membranes by method spray pyrolysis.

The study of optical properties of thin films pure and doped study spectral of absorbance and transmittance within the wavelength (200-800)nm the Results shows of the transmittance decrease of the molar concentration Increase and doped and the absorbance increase with increase molar concentration and doped and energy band gap decrease with increase molar concentration and doping the study of structure properties of the Thin films prepared through(XRD) where the results show membranes multiple crystallization and preferred trend of growth is (101) particle.
Removal of reactive blue dye from simulated wastewater by electrocoagulation using bipolar connection mode
Authors: Hadi Doaa Riyadh , AlJaberi Forat Yasir , Ajjam Sata Kazem
Published: September 2021

The present study aims to remove reactive blue dye (RBD) from simulated wastewater using a batch electrocoagulation reactor connected to a power source in a bipolar-parallel mode. The aluminum electrodes used in this work have been configured to be the interior two as perforated-plates while the outer two plates as not perforated. This investigation have conducted under the effect of the reaction time, voltage applied, and pH according to the ranges (2-80 min), (15-25 volt), and (4-12), respectively. The experimental design and the analysis of results obtained have done using response surface methodology (RSM) type central composite design (CCD) and Minitab-statistical program. The core findings revealed the treatability of the present configuration of electrodes to achieve higher removal efficiency of RBD. The complete RBD-removal was attained at the optimum values of the operating variables which were 43.75 min, 17.62 volt, and 4 of the reaction time, voltage applied, and pH, respectively. The mathematical models were significant according to the ANOVA test (p<0.001). This study proved the ability of the electrocoagulation technology to remove RBD from wastewater using the present configuration of electrodes.