bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Intraocular Tamponade in Patients with Peripheral Tear-Induced Retinal Detachment and Coexisting Macular Hole without High Myopia
Authors: Ozturk Yücel , Ağın Abdullah , Yucel Gencoglu Aysun , Talan Mustafa , Bulut Muhammed Nurullah
Published: October 2022

Introduction To introduce the surgical results and examine the effect of intraocular tamponades on surgical outcomes in patients with coexisting macular hole (MH) and rhegmatogenous retinal detachment (RRD) without high myopia.

Methods This retrospective, cross-sectional, two-center study was carried out with 29 eyes of 29 patients. The patients were divided into two groups according to the intraocular tamponade used in surgery: silicone oil (Group 1) and C3F8 gas (Group 2). In all patients, the internal limiting membrane was peeled during surgery. Exclusion criteria were determined as RRD with MH due to high myopia (≥ 6 D) without peripheral retinal tears and traumatic MH.

Results In Group 1, the median preoperative best-corrected visual acuity (BCVA) was 3.0 (M ± SD: 2.85 ± 0.27) logMAR, while the median postoperative BCVA was 1.0 (M ± SD: 1.39 ± 0.83) logMAR (p < 0.001). In Group 2, the median preoperative BCVA was 3.0 (M ± SD: 2.37 ± 0.93) logMAR, while the median postoperative BCVA was 0.76 (M ± SD: 1.06 ± 0.86) logMAR (p = 0.008). The retinal attachment success rate was 15/17 (89.3%) in Group 1, and 11/12 (91.7%) in Group 2 (p = 0.64). The MH closure rate was 12/17 (71.6%) in Group 1, and 10/12 (78.1%) in Group 2 (p = 0.52). No difference was determined between the groups in terms of preoperative and postoperative BCVA, preoperative and postoperative intraocular pressure, and BCVA improvement.

Conclusions The study results showed no significant difference between using silicone oil or C3F8 gas as an intraocular tamponade after internal limiting membrane peeling in patients with RRD due to peripheral tear with coexisting MH.
Use of Vasopressin as Rescue Therapy in Refractory Hypoxia and Refractory Systemic Hypotension in Term Neonates with Severe Persistent Pulmonary Hypertension—A Prospective Observational Study
Authors: Shah Sachin , Dhalait Saleha , Fursule Anurag , Khandare Jayant , Kaul Amita
Published: October 2022

Objective Persistent pulmonary hypertension of the newborn (PPHN) is a serious cardiorespiratory problem. PPHN is frequently associated with refractory hypoxia and hypotension, and optimal management has the potential to improve important clinical outcomes including mortality. The primary objective is to evaluate the efficacy and safety of rescue vasopressin (VP) therapy in the management of severe (refractory) hypoxia and refractory systemic hypotension in term neonates with severe PPHN.

Study Design Neonates with refractory hypoxia and refractory hypotension due to severe PPHN needing VP were prospectively enrolled in the study. Refractory hypoxia was defined as oxygenation index (OI) ≥ 25 for at least 4 hours after the commencement of high-frequency oscillatory ventilation and nitric oxide at 20 ppm. Refractory hypotension was defined as mean blood pressure lesser than mean gestational age lasting for more than 15 minutes in spite of dopamine infusion at 10 µg/kg/min, adrenaline infusion at 0.3 µg/kg/min, and noradrenaline infusion at 0.1 µg/kg/min.

Results Thirty-two neonates with PPHN were recruited. The baseline OI (mean ± standard deviation [SD]) before starting VP was 33.43 ± 16.54 which started decreasing significantly between 1 and 6 hours after the commencement of VP (p < 0.05). The mean blood pressure also increased concomitantly with a significant effect seen by 1 hour (p < 0.05). The vasoactive infusion score before the commencement of VP was mean 46.07 (SD = 25.72) and started decreasing after 12 to 24 hours of commencement of VP (p < 0.05). Lactate levels (mean ± SD) before starting VP were 7.8 ± 8.6 mmol/L and started decreasing between 6 and 12 hours (p < 0.05). Two neonates died due to refractory hypoxia and refractory hypotension (overall mortality 6.2%)

Conclusion Rescue VP therapy is a useful adjunct in the management of neonates with severe PPHN with refractory hypoxia and/or refractory hypotension. Improvement in oxygenation and hemodynamics with the use of VP results in reduced mortality.

Key Points
Neonatal and Obstetric Provider Perceptions and Management at 22 Weeks' Gestation
Authors: Nair Shah Nitya , Krishna Iris , Vyas-Read Shilpa , Patel Ravi Mangal
Published: October 2022

Objective Active treatment for periviable infants may be influenced by neonatal and obstetric provider perceptions of prognosis. The two aims of this study are to (1) quantify prognostic discordance between provider and data-driven survival estimates and (2) evaluate if prognostic discordance is associated with the threshold probability of survival at which neonatal providers recommend active treatment or obstetric providers recommend antenatal corticosteroids.

Study Design Provider survival estimates and threshold probabilities of survival for active treatment and antenatal steroid use were obtained from a case-based survey for an infant or pregnancy at 22 weeks' gestation that was administered at two Atlanta hospitals. Data-driven survival estimates, including ranges, were acquired through the National Institute of Child Health and Human Development Extremely Preterm Birth Outcomes Tool. Prognostic discordance was calculated as the difference between a provider and data-driven estimates and classified as pessimistic (provider estimate below data-driven estimate range), accurate (within range), or optimistic (above range). The association between prognostic discordance and the threshold probability of survival was evaluated using nonparametric tests.

Results We had 137 neonatal respondents (51% response rate) and 57 obstetric responses (23% response rate). The overall median prognostic discordance was 1.5% (interquartile range: 17, 13) and 52 (27%) of all respondents were pessimistic, 100 (52%) were accurate, and 42 (22%) were optimistic. The survival threshold above which neonatal and obstetric providers recommended active treatment or antenatal corticosteroids was 30% (20–45%) and 10% (0–20%), respectively. Thresholds did not significantly differ among the three prognostic discordance groups (p = 0.45 for neonatal and p = 0.53 for obstetric providers). There was also no significant correlation between the magnitude of prognostic discordance and thresholds.

Conclusion Prognostic discordance exists among both neonatal and obstetric providers. However, this discordance is not associated with the threshold probability of survival at which providers recommend active treatment or antenatal corticosteroids at 22 weeks' gestation.

Key Points
Synthesis and Reactivity of a Stable Prototropic Isomer of 2-Acetyl-3-methylpyrrole
Authors: Harran Patrick G. , Lotuzas Aleksandras , El Khoury Anton , Li Liubo
Published: October 2022

4-Isocyanobut-1-ene reacted rapidly with acetyl bromide to afford an unstable imidoyl bromide adduct. Subsequent in situ cyclization under Heck conditions generated a stable prototropic isomer of 2-acetyl-3-methylpyrrole. The reactivity of this molecule toward ­acids, bases, and oxidants was explored, and its conversion into an α-methylidene γ-lactam was demonstrated. In protonated form, the molecule functioned as a reactive dienophile in Diels–Alder reactions.
Subarachnoid Hemorrhage with Negative Initial Digital Subtraction Angiography: Subsequent Detection of Aneurysms and Complication Rates of Repeated Angiography
Authors: Nützel Regina , Brandt Silvio , Rampp Stefan , Leisz Sandra , Simmermacher Sebastian , Prell Julian , Strauss Christian , Scheller Christian
Published: October 2022

Background The data on handling of spontaneous, nontraumatic subarachnoid hemorrhage (SAH) with negative initial digital subtraction angiography (DSA) are still inconclusive. The intention of this study was to evaluate the requirement of repeat DSA in patients with negative initial DSA and to compare the clinical outcomes of these cases.

Methods In a retrospective study, we reviewed patients with SAH and negative initial DSA treated in our department from January 2006 until December 2017. The patients were divided according to an established radiographic classification into perimesencephalic (pm) and nonperimesencephalic (npm) SAH. An interventional neuroradiologist and a neurosurgeon reviewed all DSA scans.

Results In all, 52 patients with negative initial DSA, comprising 36 (69.2%) patients with pm and 16 (30.8%) patients with npm bleeding pattern, were included. All patients underwent a second and 23 of these patients underwent a third DSA. In these 23 patients, subarachnoid blood distribution in the initial computed tomography (CT) scan was suspicious for the presence of aneurysm. In total, two aneurysms were detected during the second DSA (diagnostic yield: 3.85%). Both were in the pm group (diagnostic yield: 5.6%). The second repeat DSA did not show any causative vascular lesion. Complications after the DSA occurred in only 2 of 127 patients (1.6%). The rate of complications concerning vasospasm (pm 52.8%, npm 56.3%), hydrocephalus (pm 47.2%, npm 50%), and the need for temporary or permanent shunt (pm 44.4%, npm 50%) was similar in both groups and there was no statistically significant difference.

Conclusion Repeat DSA after negative initial DSA in pm SAH had a diagnostic yield of 5.6%. However, a second repeat DSA cannot be recommended in case of SAH with initial negative DSA. The pm SAH should not be underrated concerning the occurrence of complications and cared with a high level of surveillance.
Postoperative Intracranial Hypotension-Associated Venous Congestion after Spinal Surgery Managed with Multiple Blood Patches: Case Report
Authors: Kurzbuch Arthur Robert , Bourlond Baudouin , García Martínez Juan José , Bonjour Thierry , Novaes Natalia P. , Tuleasca Constantin , Millán Diego San
Published: October 2022

Background Postoperative intracranial hypotension-associated venous congestion (PIHV) is a rare event. The authors report the case of a patient presenting with PIHV after spinal surgery following the sudden loss of cerebrospinal fluid (CSF) induced by suction drainage.

Methods A 69-year-old patient underwent uneventful revision surgery for wound dehiscence after lumbar surgery with placement of a subfascial suction drain.

Results Postoperatively, the patient presented with fluctuating consciousness and a generalized tonic–clonic seizure. Computed tomography (CT) and serial magnetic resonance imaging (MRI) were performed showing convexity subarachnoid hemorrhages (SAHs), diffuse swelling of the brain and thalami and striatum bilaterally without diffusion restriction, and signs of intracranial hypertension resulting in pseudohypoxic brain swelling in PIHV. A dural leak at L3–L4 was treated with several CT-guided patches combining autologous blood and fibrin glue injections. The patient recovered without neurologic deficit and follow-up MRI revealed progressive complete reversal of brain swelling, and re-expansion of CSF spaces.

Conclusion PIHV is a rare but potentially fatal entity. Awareness of PIHV after cranial or spinal surgery leads to early treatment of CSF hypovolemia and possibly better clinical outcome. Following acute CSF volume loss, an acute elevation of cerebral blood volume overcoming autoregulatory mechanisms seems a likely explanation for diffuse cerebral vasogenic edema and SAH in PIHV.
Cardiac Effects of COVID-19 Infection, MIS-C, and the Vaccine in Infants and Children: What Is Known and Future Implications
Authors: Schwartz Bryanna N. , Harahsheh Ashraf S. , Krishnan Anita , Martin Gerard R.
Published: October 2022

The cardiac effects of novel coronavirus disease 2019 (COVID-19) infection on the pediatric heart has become an area of particular interest as elevated cardiac enzymes and abnormalities on echocardiogram and electrocardiogram were seen in a portion of children affected by the virus. In this article, we review the cardiac manifestations of acute COVID-19 infection, multisystem inflammatory syndrome in children, and postvaccine myocarditis. The limited research on the effects of COVID-19 on neonates and infants is also reported.

Key Points
Numerical methods for free—free radiative transition matrix elements
Authors: Gao Bo , Starace Anthony F.
Published: October 2022

Increasing interest in multiphoton absorption processes above the ionization threshold has led theorists to reexamine numerical techniques for calculating radiative transition matrix elements between states of a continuum electron moving at large radial distances in the field of an atom or an ion. Here it is shown that accurate free—free radial matrix elements may be obtained using the usual dipole length formula by means of a rotation at finite distance in the complex coordinate plane together with solution of the free-electron wave function's phase and amplitude at finite distance in the complex coordinate plane. The procedure is designed for use with numerically calculated wave functions for many electron atoms and ions. It avoids the use of analytic asymptotic formulas as well as transformation to the dipole acceleration formula and is accurate even for matrix elements between electron stales that are close in energy, which is the case for which the alternative integration-by-parts method is inaccurate. We present comparisons of our numerical procedure with both analytic results and results of the integration-by-parts procedure for the case of free—free electron transitions in a pure Coulomb field.
Analysis on the crimping quality of overhead transmission line conductors considering equivalent cross-sectional stiffness
Authors: Zhang Wei , Liu Yangsheng , Li Shan , Tang Jie
Published: October 2022

Approximately 58% of wire failures are caused by slippage and fracture of electrical connectors, and the crimping quality analysis of connectors is based on equivalent cross-sectional stiffness. First, a JL/GLA 400/35 steel cord aluminum strand and NY-400/35 strain clamp are selected to fabricate 26 groups of specimens with different pipe penetration depths, opposite edge distances, inner diameters of the aluminum tube, and die widths. Then, through crimping tests on the aluminum tube and conductor and the steel core and steel anchor, five main crimping failures, namely, the slip at the outlet of the clamp, the slip at the outlet of the clamp with some broken aluminum strands, fracture of the aluminum tube in the non-pressure area, wire fracture at the outlet of the clamp, and separation of steel anchors, are observed. Finally, a failure analysis method for conductor crimping is proposed based on equivalent cross-sectional stiffness. Through the analysis of grip force and crimping quality, four failure modes and simplified curves of the load–displacement curve are obtained, and the failure principle of the conductor crimping is further elaborated. The results show that the stress release caused by the steel core and steel anchor of the crimping wire and the crimping aluminum tube and wire is the main reason for the slippage and fracture of the transmission line conductors and that it is also the key to improve the installation quality of the transmission line.
Combined spectroscopy and electrical characterization of La:BaSnO3 thin films and heterostructures
Authors: Nono Tchiomo Arnaud P. , Carleschi Emanuela , Prinsloo Aletta R. E. , Sigle Wilfried , van Aken Peter A. , Mannhart Jochen , Ngabonziza Prosper , Doyle Bryan P.
Published: October 2022

For La-doped BaSnO3 thin films grown by pulsed laser deposition, we combine chemical surface characterization and electronic transport studies to probe the evolution of electronic states in the band structure for different La-doping contents. Systematic analyses of spectroscopic data based on fitting the core electron line shapes help to unravel the composition of the surface as well as the dynamics associated with increasing doping. These dynamics are observed with a more pronounced signature in the Sn 3d core level, which exhibits an increasing asymmetry to the high binding energy side of the peak with increasing electron density. The present results expand the current understanding of the interplay between the doping concentration, electronic band structure, and transport properties of epitaxial La:BaSnO3 films.
Unsupervised learning of ferroic variants from atomically resolved STEM images
Authors: Valleti S. M. P. , Kalinin Sergei V. , Nelson Christopher T. , Peters Jonathan J. P. , Dong Wen , Beanland Richard , Zhang Xiaohang , Takeuchi Ichiro , Ziatdinov Maxim
Published: October 2022

An approach for the analysis of atomically resolved scanning transmission electron microscopy data with multiple ferroic variants in the presence of imaging non-idealities and chemical variabilities based on a rotationally invariant variational autoencoder (rVAE) is presented. We show that an optimal local descriptor for the analysis is a sub-image centered at specific atomic units, since materials and microscope distortions preclude the use of an ideal lattice as a reference point. The applicability of unsupervised clustering and dimensionality reduction methods is explored and is shown to produce clusters dominated by chemical and microscope effects, with a large number of classes required to establish the presence of rotational variants. Comparatively, the rVAE allows extraction of the angle corresponding to the orientation of ferroic variants explicitly, enabling straightforward identification of the ferroic variants as regions with constant or smoothly changing latent variables and sharp orientational changes. This approach allows further exploration of the chemical variability by separating the rotational degrees of freedom via rVAE and searching for remaining variability in the system. The code used in this article is available at https://github.com/saimani5/ferroelectric_domains_rVAE.
On the enhanced attractive load capacity of resonant flexural squeeze-film levitators
Authors: Ramanarayanan S. , Sánchez A. L.
Published: October 2022

This paper uses numerical and asymptotic methods to investigate the fluid dynamics underlying the anomalously large attractive forces that were recently observed in squeeze-film levitation systems driven by resonant vibrations of a flexible oscillator. Namely, in a recent experimental study, a thin plastic disk driven near one of its natural frequencies attractively levitated, for the first time, an object weighing several hundred grams. This behavior is in stark contrast with that of rigid-body systems, which produce attractive forces thousands of times weaker and only within a limited range of operating conditions. Flexural systems driven by standing-wave deformations of the oscillator are addressed in this paper in a unifying matched-asymptotic analysis that accounts for effects of fluid viscosity, inertia, and compressibility, as well as pressure variations beyond the outer boundary of the squeeze film. While the weak attractive forces produced by rigid-body systems are known to depend critically on the existence of a net pressure drop across this peripheral region, the present analysis reveals that the augmented attractive load capacity of resonant flexural systems is associated instead with spikes of underpressure near the nodes of the standing wave. Furthermore, the wavenumber, which represents the number of nodes in the waveform, is found to correlate strongly with the attractive load capacity as well as the range of frequencies and oscillator surface areas for which attractive forces can be produced.
Method for reconstruction of axisymmetric capillary wave surface topography using inverse ray-tracing of refracted laser sheet
Authors: Mukim V. V. , Time R. W. , Kanade U. R. , Rabenjafimanantsoa A. H.
Published: October 2022

Capillary waves can be used to measure the fundamental fluid properties such as surface tension as well as, potentially, the viscosity of Newtonian fluids. This requires the measurement of various wave parameters, mainly wavelength, amplitude, and decay coefficient. However, the different scales of magnitudes make it a challenging task. Optical methods are well suited to analyze such problems due to their non-intrusive nature and high dynamic measurement resolution in both space and time. These methods are further categorized as point methods for a single probe measurement and space–time methods for transient measurement of the complete surface. Dynamic space–time methods are preferred despite the associated complex post-processing since they enable reconstruction of the wave surface. Some existing methods are discussed, and an improved method is then proposed to actually solve the associated inverse optics problem. In the method, an axisymmetric wave surface is re-constructed by analyzing the refracted laser sheet. The assumptions, simplifications, and constraints are taken to be compatible with experimental aspects for future validation. It is derived using the fundamental concepts in physics and the only major assumption of the axisymmetric nature of wave surface. The method exploits the underlying symmetry in the topography, making it more versatile, and suited for linear and non-linear capillary waves and waves with planar wavefront. The impact of parameters on the final result is determined through numerical simulations. Very low error (average and maximum) values are observed between reference and reconstructed topography for damped and undamped wave surfaces with a wide range of curvatures. Optimum values of critical parameters and associated reasoning are presented.
An improved mayfly algorithm and its application
Authors: Zhao Mengling , Yang Xinlu , Yin Xinyu
Published: October 2022

An improved version of the mayfly algorithm called the golden annealing crossover-mutation mayfly algorithm (GSASMA) is proposed to address the low convergence efficiency and insufficient search capability of existing mayfly algorithms. First, the speed of individual mayflies is optimized using a simulated annealing algorithm to improve the update rate. The position of individuals is improved using the golden sine algorithm. Second, the impact of using different crossover and mutation methods in the algorithm is compared, and the optimal strategy is selected from the algorithm. To evaluate the performance of the algorithm, simulation experiments were carried out for 10 different test functions, and the results were compared with those of existing algorithms. The simulation results show that the algorithm developed in this paper converges faster and the solutions obtained are closer to the global optimum. Finally, GSASMA was used to optimize a support vector machine (SVM) that was used to identify the P300 signal for five subjects. The experimental results show that the SVM optimized by the algorithm proposed in this paper has higher recognition accuracy than an extreme learning machine.
Influence of donor doping on dielectric properties of calcium copper titanate ceramics
Authors: Cheng Pengfei , Wang Dan , Dang Ziyan , Luo Qiuni , Zhou Min
Published: October 2022

Calcium Copper Titanate ceramics (CaCu3Ti4O12) doped with Yb were prepared by the traditional solid–state reaction method. It is found by x-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, and X-ray photoelectron spectroscopy that Yb prefers to locate at the A site as a donor, which gives rise to the inhibition of oxygen vacancies in the grains and the segregation of Cu to the grain boundaries. Dielectric properties of the samples and electronic structure at grain boundary were investigated further by dielectric spectroscopy and specific impedance spectroscopy, respectively. It is revealed that medium frequency dielectric relaxation is restrained obviously for the decrease of oxygen vacancy, while giant dielectric permittivity (higher than 104) is maintained for the decrease of depleted layer thickness after donor doping. Therefore, the research of this paper offers an effective way to improve the dielectric properties of CaCu3Ti4O12 based on the modulation of intrinsic point defects.
Vibration and stability analysis of a tensioned moving printed electronic laminated membrane under multiple working conditions
Authors: Shao Mingyue , Zhang Miao , Wu Jimei , Guo Xuxia , Wu Qiumin , Qing Jiajuan
Published: October 2022

This paper investigated the vibration of a printed electronic laminated membrane subjected to pretension and air resistance in thermal environments. First, a mathematical model for the moving printed electronic laminated membrane is established, which considers the inhomogeneity of the tension at both ends of the membrane. The model equilibrium governing differential equation is obtained according to the classical laminate plate theory and Hamilton’s principle. The differential quadrature method is used for numerical calculation, and the effects of the aspect ratio, x-axis tension, thermoelastic coupling coefficient, dimensionless air resistance, and other parameters on the vibration of simply supported opposite sides and free opposite sides of a printed electronic laminated membrane are analyzed. The model’s accuracy is verified by comparison with the results reported in the literature. This study can provide theoretical guidance for setting printing equipment parameters and improving the transport stability of roll-to-roll printed flexible electronic laminated membranes.
First principles calculation to investigate the structural, electronic, elastic, mechanical, and optical properties of K2NiP2 ternary compound
Authors: Mbilo Mwende , Musembi Robinson
Published: October 2022

First-principles calculations of the structural, electronic, elastic, mechanical, and optical properties of the K2NiP2 ternary compound using density functional theory as implemented in the quantum espresso package have been performed. The calculations have been done using the generalized gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE, PBEsol) exchange-correlation functionals and the local density approximation (LDA). The lattice parameters have been found to agree with the available experimental results. Direct bandgaps have been obtained as 0.630, 0.588, and 0.525 eV when using the GGA-PBE, GGA-PBEsol, and LDA approximations, respectively. In all three scenarios, the valence bands have been noted to be majorly formed by Ni-3d and P-2p states with little contribution from the other states, whereas the conduction bands have been observed to be mainly formed by P-2p states with a small contribution from the other states. The K2NiP2 has been found to be mechanically stable, ductile, and ionic. The optical properties showed that the compound under investigation has a high refractive index and absorption coefficients covering the ultraviolet–visible regions, thus indicating its potential for photovoltaic applications. The bandgaps obtained using LDA were smaller than those obtained using GGA. This is because LDA underestimates the bandgaps.
Features of gate-tunable and photon-field-controlled optoelectronic processes in a molecular junction: Application to a ZnPc-based transistor
Authors: Petrov Elmar G. , Shevchenko Yevgen V. , Gorbach Victor V. , Lyubchik Svetlana , Lyubchik Andriy
Published: October 2022

Taking into account the fact that the transitions between the states of a molecular junction are carried out against the background of much faster relaxation processes in molecular terms and the conduction bands of electrodes, kinetic equations for integral occupancies of the molecular terms, as well as expressions for the time-dependent electronic current and radiation power of the fluorophore molecule, are obtained. Using the example of a molecular junction based on a ZnPc fluorophore, the transformation of a transient optoelectronic process into a stationary one is demonstrated. Corresponding analytical expressions are derived, including overall rates, which determine the characteristic times of establishing equilibrium current and light emission. The temporary process of the reorganization of the transmission channels dependently on the magnitude and polarity of the gate voltage as well as an external optical field is also demonstrated. The dependence of the overall rates on the elementary rates characterizing the recharge of the molecule, as well as radiation and nonradiative transitions in the molecule, is obtained. Estimates show that in a ZnPc-based transistor, the characteristic transition time is 10–100 ps if the current is in the range of 0.1–10 nA.
Study on the mechanism and load characteristics of secondary cavitation near free surface in underwater explosion
Authors: Yu Jun , Wu Wen-Wei , Yan Bo , Dong Jiu-Ting , Zhang Xian-Pi
Published: October 2022

Although the cavitation phenomenon in underwater explosion has been researched for more than 100 years, the phase transition models based on mass and heat exchange between liquid and its vapor phases have only been established in the past decade. In this study, the secondary cavitation phenomenon was first captured by phase transition based on a four-equation system. The bulk cavitation near the free surface induced by underwater explosion was numerically investigated, and three typical bulk cavitation cases were investigated to explore their motion mechanisms and load characteristics on hydrodynamics and phase transition generation. It was found that secondary bulk cavitation will occur only under the condition that both the initial shock wave intensity and the distance between the water surface and the explosion bubble are satisfied in a specific relationship. Producing bulk cavitation was difficult at a relatively deep detonation depth because of the weak rarefaction wave reflected from the water surface by smaller charges. The statistical data under the condition of small charge indicated that the duration of cavitation increases with the increase in charge weight but the growth trend slows down gradually. However, the maximum volume of cavitation increased linearly with an increase in the charge weight. The present results can expand the currently limited database of underwater explosion multiphase fluids and provide insight into the interactions between the shock wave, bulk cavitation, explosion bubble, and water surface.
Fluid mechanism analysis on the interaction between natural laminar flow nacelle and wingbody on a transonic aircraft
Authors: Zhang M. H. , Meng X. X. , Wang M. L. , Wang H. , Bai J. Q. , Nie S. Y.
Published: October 2022

A transonic natural laminar flow (NLF) nacelle, which is a streamlined fairing used to contain a turbofan engine and mounted under the wing of civil aircraft, can reduce friction drag. Because the fluid mechanism of the interaction between an NLF nacelle and a wingbody is not clear, laminar flow at high Reynolds numbers in the transonic regime is maintained difficultly. In this work, such interaction on a civil aircraft is investigated. Three NLF nacelles with different pressure distribution characteristics and a baseline nacelle with the turbulent flow are examined. These are installed under the wing of a widebody aircraft to investigate the fluid mechanism between a natural laminar flow nacelle and wingbody. The results show that the influence of the wingbody on the fluid characteristics of the nacelle should be considered in the NLF nacelle design. A well-designed isolated NLF nacelle is different from the one that considers the effect of the wingbody. A favorable pressure gradient in the front part of the nacelle is a key factor in drag reduction. An installed NLF nacelle owning a large pressure peak with a weak favorable pressure gradient and a strong shock wave in front of the nacelle is recommended to be applied in civil aircraft.
Coupled fluid–thermal analysis of the reduction mechanism for the drag and heat flux induced by jet interaction in a hypersonic reusable launch vehicle
Authors: Meng Yu-shan , Wang Zhong-wei , Huang Wei , Niu Yao-bin , Yan Li
Published: October 2022

The analysis of heat transfer is crucial to hypersonic vehicles that operate under high pressure and aerodynamic heat flux due to severe aero-heating. The jet concept has been applied to reduce drag and increase thermal protection. In this paper, a flow control mechanism introduced through a jet strategy equipped on the blending area with a freestream Mach number of 6 is analyzed numerically. The thermal response of the hypersonic vehicle is numerically investigated with a three-dimensional fluid–thermal coupling approach based on a loosely coupled fluid–thermal analysis. The results indicate that, throughout the coupling process, the reduced temperature growth inside the structure contributes to lowered fluid temperature gradient, thus depressing external aerodynamic heating and gradually decreasing the rate of variation in heat flux as a consequence. The calculations focus on the influence of drag reduction on the aerodynamic characteristics of the hypersonic vehicle, and the thermal protection effects of different methods are compared. The study finds that manipulating the shock structure through jet interaction is practical and promising for alleviating high flight resistance and severe aero-heating, and the jet strategy is an advantageous means of reducing drag and thermal protection for the blending area. A maximum 2.22% increase in lift coefficient and 1.98% decrease in drag coefficient are obtained, and the lift-to-drag ratio of the vehicle is improved by 4.23% with the porous jet strategy. Moreover, this strategy remarkably reduces overall heat flux to less than 108 kW/m2 along the characteristic centerline of the jet orifices.
Developing a national primary care research network: a qualitative study of stakeholder views
Authors: Pigden Abigail , Stokes Tim , Crengle Sue , Dowell Tony , Hudson Ben , Toop Les , McBain Lynn , Arroll Bruce , Gill Emily , Betty Bryan , Atmore Carol
Published: October 2022

Introduction Primary care research is critical to address Aotearoa New Zealand’s (NZ) health sector challenges. These include health inequities, workforce issues and the need for evaluation of health system changes. Internationally, primary care data are routinely collected and used to understand these issues by primary care research and surveillance networks (PCRN). NZ currently has no such infrastructure. Aim To explore health sector stakeholders’ views on the utility of, and critical elements needed for, a national PCRN in NZ. Methods Twenty semi-structured interviews and a focus group were conducted with key stakeholders, representing different perspectives within the health sector, including Hauora Māori providers. Data were analysed thematically. Results Six themes were identified that included both challenges within current primary care research and ideas for a future network. The themes were: disconnection between research, practice and policy; desire for better infrastructure; improving health equity for Māori and other groups who experience inequity; responding to the research needs of communities; reciprocity between research and practice; and the need for data to allow evidence-informed decision-making. Improving health equity for Māori was identified as a critical function for a national PCRN. Discussion Stakeholders identified challenges in conducting primary care research and translating research into practice and policy in NZ. Stakeholders from across the health sector supported a national PCRN and identified what its function should be and how it could operate. These views were used to develop a set of recommendations to guide the development of a national PCRN.
Effects of verb and construction frequency in sentence comprehension
Authors: Kim Hyunwoo , Shin Gyu-Ho
Published: October 2022

Two theoretical viewpoints provide different explanations about how people extract statistical regularities from
input to assess the felicity of verb usage in a sentence. The lexical approach emphasizes the role of verb frequency in
determining a verb’s distributional bias within a sentence, whereas the entrenchment hypothesis highlights the conjoined roles of the frequency information from both a verb and an argument structure construction. The present study tests these accounts by
investigating Korean speakers’ interpretation of two dative patterns in Korean (Dative–Accusative and Accusative–Accusative).
Through the analysis of a large-scale corpus, we calculated the frequency of each dative pattern as well as the frequency of
dative verbs occurring therein. Using this information, we conducted an acceptability judgment task with Korean speakers by
manipulating the dative type and the verb frequency. The results showed that the speakers’ acceptability rating behavior was
affected by the interaction between the verb and construction frequency such that highly entrenched verb–construction
combinations were evaluated to be more acceptable. Our finding supports the entrenchment hypothesis that emphasizes the conjoined
roles of usage frequency of verbs and constructions in sentence comprehension.
Platelet-derived TLT-1 promotes tumor progression by suppressing CD8+ T cells
Authors: Tyagi Tarun , Jain Kanika , Yarovinsky Timur O. , Chiorazzi Michael , Du Jing , Castro Cecilia , Griffin Jules , Korde Asawari , Martin Kathleen A. , Takyar Shervin S. , Flavell Richard A. , Patel Abhijit A. , Hwa John
Published: October 2022

Current understanding of tumor immunosuppressive mechanisms forms the basis for modern day immunotherapies. Immunoregulatory role of platelets in cancer remains largely elusive. Platelets from non-small cell lung cancer (NSCLC) patients revealed a distinct activation phenotype. TREM-like transcript 1 (TLT-1), a platelet protein, was increased along with enhanced extracellular release from NSCLC platelets. The increased platelet TLT-1 was also evident in humanized mice with patient-derived tumors. In immunocompetent mice with syngeneic tumors, TLT-1 binding to T cells, in vivo, led to suppression of CD8 T cells, promoting tumor growth. We identified direct interaction between TLT-1 and CD3ε on T cells, implicating the NF-κB pathway in CD8 T cell suppression. Anti–TLT-1 antibody rescued patients’ T cells from platelet-induced suppression ex vivo and reduced tumors in mice in vivo. Clinically, higher TLT-1 correlated with reduced survival of NSCLC patients. Our findings thus identify TLT-1 as a platelet-derived immunosuppressor that suppresses CD8 T cells and demonstrate its therapeutic and prognostic significance in cancer.
The funny current If is essential for the fight-or-flight response in cardiac pacemaker cells
Authors: Peters Colin H. , Rickert Christian , Morotti Stefano , Grandi Eleonora , Aronow Kurt A. , Beam Kurt G. , Proenza Catherine
Published: October 2022

The sympathetic nervous system fight-or-flight response is characterized by a rapid increase in heart rate, which is mediated by an increase in the spontaneous action potential (AP) firing rate of pacemaker cells in the sinoatrial node. Sympathetic neurons stimulate sinoatrial myocytes (SAMs) by activating β adrenergic receptors (βARs) and increasing cAMP. The funny current (If) is among the cAMP-sensitive currents in SAMs. If is critical for pacemaker activity, however, its role in the fight-or-flight response remains controversial. In this study, we used AP waveform analysis, machine learning, and dynamic clamp experiments in acutely isolated SAMs from mice to quantitatively define the AP waveform changes and role of If in the fight-or-flight increase in AP firing rate. We found that while βAR stimulation significantly altered nearly all AP waveform parameters, the increase in firing rate was only correlated with changes in a subset of parameters (diastolic duration, late AP duration, and diastolic depolarization rate). Dynamic clamp injection of the βAR-sensitive component of If showed that it accounts for ∼41% of the fight-or-flight increase in AP firing rate and 60% of the decrease in the interval between APs. Thus, If is an essential contributor to the fight-or-flight increase in heart rate.
Gravitational waves induced from primordial black hole fluctuations: the effect of an extended mass function
Authors: Papanikolaou Theodoros
Published: October 2022

The gravitational potential of initially Poisson distributed primordial black holes (PBH) can induce a stochastic gravitational-wave background (SGWB) at second order in cosmological perturbation theory. This SGWB was previously studied in the context of general relativity (GR) and modified gravity setups by assuming a monochromatic PBH mass function. Here we extend the previous analysis in the context of GR by studying the aforementioned SGWB within more physically realistic regimes where PBHs have different masses. In particular, starting from a power-law cosmologically motivated primordial curvature power spectrum with a running spectral index we extract the extended PBH mass function and the associated to it PBH gravitational potential which acts as the source of the scalar induced SGWB. At the end, by taking into account the dynamical evolution of the PBH gravitational potential during the transition from the matter era driven by PBHs to the radiation era we extract the respective GW signal today. Interestingly, in order to trigger an early PBH-dominated era and avoid the GW constraints at BBN we find that the running of the spectral indexαsof our primordial curvature power spectrum should be within the narrow rangeαs⋲ [3.316,3.355] × 10-3while at the same time the GW signal is found to be potentially detectable by LISA.
Half-disk lasers with active region based on InGaAs/GaAs quantum well-dots
Authors: Zubov Fedor I , Moiseev Eduard I , Maximov Mikhail V , Vorobyev Alexandr A , Mozharov Alexey M , Shernyakov Yuri M , Kalyuzhnyy Nikolay A , Mintairov Sergey A , Kulagina Marina M , Dubrovskii Vladimir G , Kryzhanovskaya Natalia V , Zhukov Alexey E
Published: October 2022

Half-disk lasers fabricated by cleaving initial full-disk lasers have an advantage of directional light outcoupling as well as increased output power and efficiency as compared to full-disk lasers of the same diameter. The continuous wave output power of a 200 µm diameter half-disk laser exceeds 70 mW. Quasi single-mode lasing with a high side-mode suppression ratio more than 20 dB is demonstrated for half-disk lasers of various diameters. A maximum 3 dB small signal modulation frequency of 4.9 GHz was measured for a 100 µm in diameter half-disk laser.
Process Optimization of Non-Holonomic Surface Milling for Al-Si7Mg Component
Authors: Qin Bo , Wu Hao , Li Peilu
Published: October 2022

Milling process enhancement for an aluminium alloy component with a large bore and variable wall thickness for incomplete circular surfaces, research on the optimization of milling process parameters based on machining stability and machining deformation control was carried out. Analysis of the formation mechanism of the regeneration effect caused by casting defects in cast aluminium parts, the stability lobe diagrams are plotted by the zero-order frequency domain analysis method, and the effects of radial depth of cut, cis-reverse milling and the dynamics parameters of the milling system on the boundary range of the stability lobe diagram were investigated. By orthogonal simulation analysis of milling deformation, determine the primary and secondary relationship between the influence of each process parameter on the machining deformation and the optimal combination of each process parameter in the test range. The results show that in the milling process, reducing the radial depth of cut, using a more rigid milling cutter and reverse milling can all be effective in improving the stability of the process; The significant influence of process parameters on the amount of machining distortion is: radial depth of cut > feed rate > cutter’s speed, the optimal combination of process parameters is: cutter’s speed 600 r/min, radial depth of cut 0.2 mm, feed rate 150 mm/min.The process parameters are used for machining verification, the surface roughness of the annular hole was improved from 6.3 to 3.2 before the optimization, and the coaxiality was improved from 0.12mm to 0.05mm before the optimization. The results show that Optimised milling process parameters improve part quality.
Analysis of surface blackening defects on hot-rolled pickled steel
Authors: Li Yan , Wang Ke-qiang , Sun Rong-sheng , Liu Ren-dong , Tian Yu-ting , Cai Shun-da , Song Li-wei
Published: October 2022

There are many blackening defects on the steel surface after the pickling of the hot-rolled strip. The microstructure and roughness of the picked steel surface were analyzed using SEM and LEXT OLS4000 laser scanning confocal microscope, XPS, and surface roughness measure. The experiment result shows that the blackening defects of the hot-rolled pickled steel sheet surface are aging of anti-rust oil film to the strip steel surface. In order to improve the surface quality of the hot rolling pickled sheet, the anti-rust oil coating process is improved, the thickness and uniformity of the oil film are controlled, and the management in the course of packing, storage and transportation are strengthened.
Weldability of Nickel/Aluminum Dissimilar Materials Laser Welding Part II: Microstructure Development, Solidification Behavior and Mechanical Properties of Polycrystalline Aluminum Alloy
Authors: Gao Zhiguo
Published: October 2022

The weldability and fabricability of nonheat treatable Aluminum-Magnesium alloy 5083H116 in shipbuilding industry by attractive laser welding are progressively assessed in this paper. The response of crack-resistant microstructure development, phase transformation and mechanical properties to energy input is very sensitive and distinguishable during laser welding process. Supersaturation of α-Al solid solution is prominently released by granular Al3Mg2 β phase during rapid solidification. Keyhole weld profile leads to parabolic-shaped distributions of alloying components and nonequilibrium β phase. Heat flow and solute elements are thermometallurgically accumulated in neck region, where maximum β phase and alloying element cluster are located. Asymmetrically, amount of Magnesium-rich β phase in the left portion of weld is the largest, dispersive β phase nearby weld center softening region is the lowest, where mechanical properties are worst, and diffusion-limited β phase in the right side is intermediate. There is significant discrepancy between left side, right side and center part of weld in solute redistribution and β/α eutectic phase transformation, which substantially contribute to obvious tensile properties fluctuation. Nucleation and growth of a few β phase particles in the dimple heterogeneously weaken weld integrity and are detrimental to weld strength and ductility. Weld specimens ductilely fracture in the center part, and plastically experience much deformation. Fracture surface morphologies show plenty of large and deep dimples after intense plastic deformation. Loss of strengthening elements and hydrogen-related porosity are attributed to evaporation-dependent weld pool instability. Additionally, the eutectic-driven microstructure analysis results are in consonance with mechanical behavior. The internal temperature development, molten pool duration, solid/liquid interface location, heat dissipation and weld quality should be appositely balanced by processing variables rearrangement.
FEM simulation investigation of ultrasonic vibration-assisted grinding of SiCf/SiC composites
Authors: Zhang Zikang , Yuan Songmei , An Wenzhao , Xu Weiwei
Published: October 2022

In this study, a finite element model (FEM) of a single diamond grinding SiCf/SiC composites was established, and the process of ultrasonic vibration-assisted grinding was simulated and investigated from a microscopic perspective. The damage behavior and removal mechanism of ultrasonic vibration-assisted grinding along across fibers, longitudinal fibers, and transverse fibers were analyzed, respectively. Simulation results show that brittle fracture is the main removal mechanism of the matrix. The damage behavior of fibers mainly includes fiber breakage, fiber fracture, fiber pull-out, and fiber debonding. There are large differences in the removal mechanism of materials ground in different fiber directions. The simulation results provide important guidance for a better understanding of the damage behavior and removal mechanism of ultrasonic vibration-assisted grinding of SiCf/SiC composites.