Typical Curve Research Articles

The Early Ultraviolet Light Curves of Type II Supernovae and the Radii of Their Progenitor Stars

We present a sample of 34 normal Type II supernovae (SNe II) detected with the Zwicky Transient Facility, with multiband UV light curves starting at t ≤ 4 days after explosion, and X-ray observations. We characterize the early UV-optical color, provide empirical host-extinction corrections, and show that the t > 2 day UV-optical colors and the blackbody evolution of the sample are consistent with shock cooling (SC) regardless of the presence of “flash ionization” features. We present a framework for fitting SC models that can reproduce the parameters of a set of multigroup simulations up to 20% in radius and velocity. Observations of 15 SNe II are well fit by models with breakout radii <1014 cm. Eighteen SNe are typically more luminous, with observations at t ≥ 1 day that are better fit by a model with a large >1014 cm breakout radius. However, these fits predict an early rise during the first day that is too slow. We suggest that these large-breakout events are explosions of stars with an inflated envelope or with confined circumstellar material (CSM). Using the X-ray data, we derive constraints on the extended (∼1015 cm) CSM density independent of spectral modeling and find that most SN II progenitors lose Ṁ<10−4M⊙yr−1 up to a few years before explosion. We show that the overall observed breakout radius distribution is skewed to higher radii due to a luminosity bias. We argue that the 66−22+11% of red supergiants (RSGs) explode as SNe II with breakout radii consistent with the observed distribution of RSGs, with a tail extending to large radii, likely due to the presence of CSM.

Assisting Directional Drilling by Calculating a Safe Operating Envelope

Summary Nowadays, complex 3D trajectories are executed with a succession of circular arcs (CAs). Although they have constant curvature, their tool face is not constant. Consequently, directional drillers must adjust the tool face regularly to reach the target entry within its tolerances. This paper investigates the use of the constant curvature and constant tool face (CTC in short) curve as an alternative to the CA to assist the directional drilling work to reach the target entry within its boundaries. The problem is addressed by calculating a safe operating envelope (SOE) to reach the boundaries of the target entry and provide a tolerance window for the curvature and tool face to support directional drilling decisions. The target entry tolerance is discretized as a polygon. From the current bit position and its direction, the possible choices of curvatures and tool faces are obtained to reach the edges of the target entry shape. The SOE can be calculated with the CA or with the CTC curve. It is, therefore, possible to compare the advantages and disadvantages of both types of curves to attain the target entry and stay within its boundaries. The CA is shorter than the CTC curve. However, it requires adjusting the tool face during the navigation, which is not the case with the CTC curve. As a result, the directional driller can control the bottomhole assembly (BHA) direction such that the well lands within the target entry limits by using set points for tool face and curvature inside the calculated SOE. Furthermore, a new way to represent the SOE is introduced. It makes use of a 3D cylindrical representation where the curvature is mapped as the height of a cylinder, while the tool face corresponds to the azimuth in the cylindrical coordinate system, and the length is linked to the radial distance. This provides a visual aid to understand the SOE. Moreover, this visualization helps to appreciate the relationship between the initial bit location and direction in the construction of the SOE and how the margins increase in a particular manner as the bit approaches the target entry polygon. The CTC curve is the natural one followed by directional positive displacement motors (PDMs) or rotary steerable systems (RSS). Potentially, the CTC curve may be a more straightforward solution to automated directional drilling control because it is easier to be followed by both PDM and RSS.

Damaged mortise–tenon joint strengthened using an assembled spring–steel hoop based on a design of similar rotational stiffness

The excessive enhancement of rotational stiffness leads to an uneven distribution of rotational stiffness across the entire timber frame. This uneven distribution concentrates the load effect on the strengthened mortise–tenon joints (MJs), causing localized failure in advance. To address this issue, a reversible and non-destructive strengthening method for the damaged MJs is devised, involving the utilization of an assembled spring-steel hoop. The rotational stiffness of a strengthened MJ is derived from the springs that link the steel hoop of the beam and column, resembling the rotational stiffness of an intact MJ. A comparison of the measured moment-rotation curves of various types of MJ reveals that the rotational stiffness similarity necessitates the strengthened MJ's yield moment and ultimate moment, along with the associated rotation angles, to closely resemble those of the intact MJ. Secondly, a design methodology is developed for the assembled spring-steel hoop, which involves determining the parameters of the connecting spring. The comparative analysis of the hysteretic test results on multiple strengthened and intact MJs indicates that the strengthened MJs exhibit rotational stiffness deviations of less than 12.2 % during the elasticity stage and 6.6 % during the plasticity stage, in comparison to the intact MJs. A spring exhibits a lower ultimate extension compared to timber, leading to a maximum discrepancy of 37.5 % in the ductility coefficients between the strengthened MJs and intact MJs. The strengthened and intact MJs display similar patterns of stiffness reduction and energy dissipation progression.

Rate Transient Analysis for Multi-Fractured Wells in Tight Gas Reservoirs Considering Multiple Nonlinear Flow Mechanisms

Making rate transient analysis (RTA) and formation evaluation for multi-fractured tight gas wells has always been a difficult problem. This is because the fluid flow in the formation has multiple nonlinear flow mechanisms, including gas-water two-phase flow, gas slippage, low-velocity non-Darcy flow, and stress-dependent permeability. In this paper, a novel RTA method is proposed for multi-fractured wells in tight gas reservoirs incorporating nonlinear flow mechanisms. The RTA method is based on an analytical model, which is modified from the classical trilinear flow model by considering all the nonlinear flow mechanisms. The concept of material balance time and normalized rate is used to process the production data for both water and gas phases. The techniques of approximate solutions in linear/bilinear flow regimes and type curve fitting are combined in the proposed RTA method. After that, the rate transient behaviors and influencing factors of multi-fractured tight gas wells are analyzed. A field case from Northwestern China is used to test the efficiency and practicability of the proposed RTA method. The results show that six flow regimes for both gas and water production performances are exhibited on the log-log plots of normalized production rate against material balance time. The rate transient responses are sensitive to the nonlinear flow mechanisms, and formation and fracture properties. The medium flow regimes are significantly affected by fracture number, fracture conductivity, fracture half-length, stress-dependent permeability, gas-water two-phase flow, and formation permeability, which should be considered in making RTA of fractured tight gas wells. The field case shows that both gas and water production performances can be well-fitted using the proposed RTA method. The major innovation of this paper is that a novel RTA method is proposed for fractured tight gas wells considering multiple nonlinear flow mechanisms, and it can be used to make reasonable formation and fracturing evaluations in the field.

Structural evolution during inverse vulcanization

Inverse vulcanization exploits S8 to synthesize polysulfides. However, evolution of products and its mechanism during inverse vulcanization remains elusive. Herein, inverse vulcanization curves are obtained to describe the inverse vulcanization process in terms of three stages: induction, curing and over-cure. The typical curves exhibit a moduli increment before declining or plateauing, reflecting the process of polysulfide network formation and loosing depending on monomers. For aromatic alkenes, in the over-cure, the crosslinked polysulfide evolves significantly into a sparse network with accelerated relaxation, due to the degradation of alkenyl moieties into thiocarbonyls. The inverse vulcanization product of olefins degrades slowly with fluctuated relaxation time and modulus because of the generation of thiophene moieties, while the inverse vulcanization curve of dicyclopentadiene has a plateau following curing stage. Confirmed by calculations, the mechanisms reveal the alkenyl groups react spontaneously into thiocarbonyls or thiophenes via similar sulfur-substituted alkenyl intermediates but with different energy barriers.

EVALUATION OF THE STRUCTURAL-MECHANICAL PROPERTIES OF COMPOSITE PEAR JELLIES PREPARED WITH DIFFERENT GELLING TIME AND CALCIUM SALTS

The aim was to investigate the influence of different calcium salts and gelation times on the structural-mechanical parameters of a pear composite jellies. Calcium citrate and calcium lactate with a concentration of 0.6 % and 1.2 % were used as sources of calcium ions for the gelling time of 24 and 48 h. The changes in the structural-mechanical properties of the jellies were determined from the obtained typical curves through a penetration test using a texture analyzer. The increase in the concentration of calcium ions led to the increasing values of the structuralmechanical parameters of the fruit jellies, except for adhesiveness and rupture deformation. The shape of the penetration curves was determined to a greater extent by the type and concentration of calcium salts and to a lesser extent by the gelation time. The Pearson correlation coefficients for the compressive stress, deformation force and firmness increased compared to the other structural-mechanical properties with an increase in the gelation time and the concentration of calcium salts.

Distribution and correlation analysis of typical features of electricity use profiles in non-residential buildings

Building electrical system will play a critical role in the demand response of future distributed energy systems. Understanding the distributive characteristics of the physical features of building electricity use profiles provides a useful reference for planning and designing building electrical systems. This study proposed a methodology and framework for analyzing the distribution and correlations of physical electricity use features. Five physical features were extracted from the electricity use profiles of the buildings. For value-based features, including the weekend ratio and variation factor, distribution fitting and feature regression were conducted to reveal correlations with attributes such as building types and sizes. For curve-based features, including the power-temperature curve, weekday and weekend schedules, clustering analysis was first used to identify several typical curves, and CART classification models were developed to establish correlations between typical curve types and building attributes. The proportions and distributions of all features were analyzed based on a dataset of 4168 non-residential buildings in Jiangsu Province, China. The K–S test p-values of the fitted distributions of weekend ratios and variation factors were 0.074 and 0.189, respectively. The overall accuracies of the CART classification model for power-temperature types, weekday schedule types and weekend schedule types were 62.7 %, 66.3 % and 56.7 % respectively. Potential application procedures and tools were provided for practical use. Variations in weekday and weekend schedules are discussed, and future research perspectives are outlined. The proposed methodology and results provide useful support for the planning and design of distributed building electrical systems.

Fay Identities of Pfaffian Type for Hyperelliptic Curves

We establish identities of Pfaffian type for the theta function associated with twice or half the period matrix of a hyperelliptic curve. They are implied by the large size asymptotic analysis of exact Pfaffian identities for expectation values of ratios of characteristic polynomials in ensembles of orthogonal or quaternionic self-dual random matrices. We show that they amount to identities for the theta function with the period matrix of a hyperelliptic curve, and in this form we reprove them by direct geometric methods.

Back pain in adolescent idiopathic scoliosis: frequency and risk factors

PurposeAlthough back pain is commonly reported in patients with adolescent idiopathic scoliosis (AIS), factors that influence the presence and severity of back pain in AIS, including curve-specific variables, have not been well studied. This study aims to describe the prevalence and severity of back pain in AIS patients and determine the extent to which patient characteristics, including curve-specific factors, are associated with a higher risk of back pain in AIS.MethodsThe study was a retrospective medical records review of adolescents (aged 10–17 years) diagnosed with AIS between 01/01/2018 and 12/31/2021 at an academic tertiary children’s hospital. Patients with previous spine surgery were excluded. Variables collected included demographics (age, sex, race, insurance), Lenke classification, major coronal curve, back pain-related information, Risser stage, vitamin D levels, post-diagnosis brace utilization, physical therapy or chiropractic treatment, and surgery.ResultsA total of 891 AIS patients were included in the analysis. The sample was predominantly female (73.3%) and insured by Medicaid (57.8) with a mean age of 12.8 years. The mean major coronal curve was 26.3 degrees. Most patients had Lenke type 1 (47%) and type 5 (41%) curves. Nearly half of patients reported back pain (48.5%) with average pain severity in the low-to-moderate range (4.7) on FACES pain scale (0–10). Among those who reported back pain, 63.2% specified a location with the majority reporting pain in the lumbar region (56%) and, less commonly, in the thoracic (39%) and scapular (8%) regions. Lumbar pain was associated with significantly higher pain intensity (p = 0.033). Additionally, the location of pain reported was associated with location of major coronal curve (p < 0.0001). No association was observed between pain presence and vitamin D deficiency (p = 0.571, n = 175), major coronal curve magnitude (p = 0.999), Lenke curve type (p = 0.577), and sex (p = 0.069). Older patients, those insured by Medicaid, and those with higher Risser scores were more likely to report pain scores (p = 0.001 for all).ConclusionNearly half (48%) of newly diagnosed AIS patients experience back pain which is higher than the prevalence of 33% seen in the general adolescent population. Pain was more prevalent among patients over the age of 13, with heavier body weight, and those insured by Medicaid. Pain was most commonly reported in the lumbar region, especially among patients with lumbar curves. This information can be helpful in counseling AIS patients, though further investigations are needed, especially to determine the underlying causes of back pain in AIS and to elucidate the discrepancy in pain between patients with Medicaid and commercial insurance.Level of evidence.Prognostic Study Level II.

Transient Pressure Behavior of CBM Wells during the Injection Fall-Off Test Considering the Quadratic Pressure Gradient.

Conventional coalbed methane (CBM) reservoir models for injection fall-off testing often disregard the quadratic pressure gradient's impact. This omission leads to discrepancies in simulating the transient behavior of formation fluids and extracting critical reservoir properties. Accurate determination of permeability, storability, and other properties is crucial for effective reservoir characterization and production forecasting. Inaccurate estimations can lead to suboptimal well placement, ineffective production strategies, and ultimately, missed economic opportunities. To address this shortcoming, we present a novel analytical model that explicitly incorporates the complexities of the quadratic pressure gradient and dual-permeability flow mechanisms, prevalent in many CBM formations where nanopores are rich, presenting a kind of natural nanomaterial. This model offers significant advantages over traditional approaches. By leveraging variable substitution, it facilitates the derivation of analytical solutions in the Laplace domain, subsequently converted to real-space solutions for practical application. These solutions empower reservoir engineers to generate novel type curves, a valuable tool for analyzing wellbore pressure responses during injection fall-off tests. By identifying distinct flow regimes within the reservoir based on these type curves, engineers gain valuable insights into the dynamic behavior of formation fluids. This model goes beyond traditional approaches by investigating the influence of the quadratic pressure gradient coefficient, inter-porosity flow coefficient, and storability ratio on the pressure response. A quantitative comparison with traditional models further elucidates the key discrepancies caused by neglecting the quadratic pressure gradient. The results demonstrate the proposed model's ability to accurately depict the non-linear flow behavior observed in CBM wells. This translates to more reliable pressure and pressure derivative curves that account for the impact of the quadratic pressure gradient.

RIGHT LEFT DISCRIMINATION PERFORMANCE OF BODY PARTS IN INDIVIDUALS WITH SCOLIOSIS

ABSTRACT This study aimed to examine the right-left discrimination of hands, feet and back in individuals with scoliosis. In the study, right-left discrimination performance was evaluated with the mobile application called Recognize, radiographic features of scoliosis were evaluated with X-ray, degree of rotation was evaluated with the mobile application called Scoliodetector, and back pain was evaluated with the Visual Analog Scale. 25 individuals with idiopathic scoliosis were included in the analysis. In the comparison made according to the thoracolumbar and lumbar curve, no difference was found between the groups in the lateralization performances (p&gt;0.05). In the comparison according to the type of curve, no significant difference was observed in the reaction time and accuracy rate between the groups (p&gt;0.05). When comparing the lateralization performance according to the direction of the curve, a significant difference was found between the groups in the left foot and back reaction times (p

Determination of Reservoir Parameter of Naturally Fractured Reservoir at SF Field using Rate Type Curve Analysis

This Naturally Fractured Reservoir (NFR) is become challenging to identify the behavior of performance in fluid flow in producing well at SF oil Field. Generally, this unique of mechanism that cannot be treated as homogenous reservoir, because has two porous media in this reservoir such as matrix and fracture, the dominantly fluid flow comes from the networks of fractures, but for matrix porous media as function of source that transfer fluid to the fractures. This complexity of reservoir needs deepest investigate the characteristic of this reservoir and estimating the reservoir parameter such as permeability fracture, storativity coefficient ratio (omega) and interporosity flow coefficient (lamda) of SF production wells at SF oil Field are the main objective of this study. There are two wells that are analyzed in this study, and the result of this study yields significant interpretation by analyzing the production data in order to approximate the characteristic of dual porosity in naturally fractured oil reservoir by applying the decline rate type curve matching.

VO2 thin films: various microstructures for hysteresis manipulations

Vanadium dioxide reveals a phase change transition at 68 °C associated to typical hysteresis curves with strong variations in physico-chemical properties. The study presented here aims to investigate the influence of the structure and the microstructure of VO2 condensed matter on optical transmittance and electrical resistivity hysteresis curves during the metal-insulator transition. The characteristics of VO2 thin films synthesized through conventional laser ablation and of VO2 nanoparticle stacks generated via a laser vaporization cluster source are investigated. This study reveals the capability to modulate the transition temperature by as much as 20 °C, the transition width within the range of 4–30 °C, and the resistivity dynamics across the semiconducting-to-metallic phase transition by more than two orders of magnitude. These effects appear to arise because of the change of microstructure, the physical percolation of nanoparticles and associated collective effects.More complex hysteresis behaviors, taking benefit of the fabrication processes presented in this paper, and coupling the two previous distinct VO2 architectures (thin film and nanoparticles stack) lead to optical transmittance curves with three transition levels. This approach offers flexibility beyond binary responses, facilitating the design of innovative optoelectronic devices with n-stages modulation capabilities. Near room temperature applications of VO2 metal-insulator transition are underscored, highlighting opportunities for tailored architectures to exploit its properties effectively.

Precursor-Confined Chemical Vapor Deposition of 2D Single-Crystalline SexTe1-x Nanosheets for p-Type Transistors and Inverters.

Two-dimensional (2D) tellurium (Te) is emerging as a promising p-type candidate for constructing complementary metal-oxide-semiconductor (CMOS) architectures. However, its small bandgap leads to a high leakage current and a low on/off current ratio. Although alloying Te with selenium (Se) can tune its bandgap, thermally evaporated SexTe1-x thin films often suffer from grain boundaries and high-density defects. Herein, we introduce a precursor-confined chemical vapor deposition (CVD) method for synthesizing single-crystalline SexTe1-x alloy nanosheets. These nanosheets, with tunable compositions, are ideal for high-performance field-effect transistors (FETs) and 2D inverters. The preformation of Se-Te frameworks in our developed CVD method plays a critical role in the growth of SexTe1-x nanosheets with high crystallinity. Optimizing the Se composition resulted in a Se0.30Te0.70 nanosheet-based p-type FET with a large on/off current ratio of 4 × 105 and a room-temperature hole mobility of 120 cm2·V-1·s-1, being eight times higher than thermally evaporated SexTe1-x with similar composition and thickness. Moreover, we successfully fabricated an inverter based on p-type Se0.30Te0.70 and n-type MoS2 nanosheets, demonstrating a typical voltage transfer curve with a gain of 30 at an operation voltage of Vdd = 3 V.

A Data-Driven Method for Parametric PDE Eigenvalue Problems Using Gaussian Process with Different Covariance Functions

Abstract We use a Gaussian Process Regression (GPR) strategy to analyze different types of curves that are commonly encountered in parametric eigenvalue problems. We employ an offline-online decomposition method. In the offline phase, we generate the basis of the reduced space by applying the proper orthogonal decomposition (POD) method on a collection of pre-computed, full-order snapshots at a chosen set of parameters. Then we generate our GPR model using four different Matérn covariance functions. In the online phase, we use this model to predict both eigenvalues and eigenvectors at new parameters. We then illustrate how the choice of each covariance function influences the performance of GPR. Furthermore, we discuss the connection between Gaussian Process Regression and spline methods and compare the performance of the GPR method against linear and cubic spline methods. We show that GPR outperforms other methods for functions with a certain regularity.

Dynamic subsidence in the Colorado basin, offshore Argentina, South Atlantic

The Colorado basin in the SW Atlantic is one of the key exploratory frontier basins along the Argentine shelf. The stratigraphy shows a typical rift basin, divided into two major seismic successions, a Jurassic-Lower Cretaceous synrift followed by an Upper Cretaceous to Cenozoic postrift. They represent, respectively, the breakup of Gondwana and passive margin evolution. While the synrift basin formation was associated with the development of structural grabens, the preservation of thick (thousands of meters) postrift sequences are still debated because they cannot be accounted for only by thermal subsidence. In this work, we conducted a multimethodological subsidence analysis across the Colorado basin, including part of the continental slope. We performed a 1D backstripping analysis on 10 hydrocarbon exploration wells and 32 pseudo-wells, covering the whole basin area and a uniform stretching model, which were supported using dynamic topography data from the study region. From the backstripping analyses, considering the six major postrift sedimentary successions described in the literature, we could recognize three subsidence stages. An initial rapid subsidence stage during the post-rift (125–83 Ma), which is restricted to the main depocenters, followed by a stage of generalized and low subsidence focused on the main axis of the basin (83–33 Ma), with an increase in the last 33 my (33–0 Ma). The stretching models exhibit a typical asymptotic curve, depicting significant subsidence at the onset of the postrift stage, gradually diminishing to minimal values within a few tens of millions of years. Upon comparing the backstripping curves with the stretching subsidence models, particularly during the final flat segments, a residual negative value emerges over time (locally exceeding −500 m), indicating considerable residual subsidence during the Cenozoic postrift evolution along the Colorado Basin. This could be interpreted as dynamic subsidence. This residual sinking in the Argentina shelf matches with dynamic topography numerical models in the study region as well as the occurrence of accumulated slabs in the mantle detected by seismic tomography studies. We propose that the accumulation of slabs along this segment of the South American subduction zone might be the drivers of dynamic subsidence, which assisted to the preservation of a large thickness of post-rift strata along the SW Atlantic margin.

Soil–water contamination assessment due to dumpsite-impacted leachates in a metamorphic environment

Environmental contamination is a complex issue that significantly impacts human health and ecological systems, especially in developing countries like Nigeria. This study explores the interplay between surface-subsurface soil-rock resistivity and subsurface geotechnical properties, along with multiple soil-water pollution indices at and around the Old Owo-Ikare road (OOIR) dumpsite in southwestern Nigeria. Water samples from five wells and one stream were collected and analyzed, alongside twelve soil samples from four trial pits at varied depths for geoenvironmental assessment. Analyzed hydrogeochemical parameters include Na, Ca, Mg, K, Cr, Pb, Zn, Ni, Mn, Fe, and cations (NO, SO4, Cl) in the water samples. Nine dipole-dipole electrical resistivity tomography (ERT) profiles and six Schlumberger vertical electrical sounding (VES) points were used to determine surface–subsurface resistivity distribution. Water analysis results showed elevated levels of K, Ni, Cr, and Pb concentrations. Geotechnical tests indicated that most dumpsite soil meets good landfill material criteria with low permeability (5.92×10−6 to 1.49×10−4cm/s). ERT and VES inverted models revealed four lithologic layers with two main curve types (HA and QA). Elevated heavy metal levels in the dumpsite soil and inverted resistivity models suggested leachate contamination in the topsoil and weathered bedrock units. Despite relatively lower heavy metal concentrations compared to other Nigerian and Ghanaian dumpsites, multi-pollution indices indicated significant contamination in both water and soil samples, posing moderate to very high environmental risks based on World Health Organisation standards. Additionally, human health risk assessment suggested a risk of cancer and non-cancer-related diseases from prolonged well water consumption. Therefore, ongoing monitoring and remediation efforts are essential to forestall imminent pollution in uncovered areas.

Correlation properties of complete code of binary spread spectrum phase-shift keyed signals with polarization coding

Problem statement. Investigation of correlation properties of complete code of binary spread spectrum phase-shift keyed signals as the limiting case of large systems is a topical task for building large systems of binary spread spectrum phase-shift keyed signals with polarization coding with optimal correlation properties. Also, this task is of independent academic interest due to the fact that the alphabet of symbols for these signals lacks multicasting properties unlike the familiar cases of complete codes of spread spectrum phase-shift keyed signals. Objective. To accurately define the distribution laws as well as the moments about zero and the mean for the n-th order of presented values of aperiodic and periodic correlation functions of the complete code of binary spread spectrum phase-shift keyed signals with polarization coding. To offer approximations of accurate distribution laws suitable for engineering applications. Results. The accurate distribution laws for presented values of aperiodic and periodic correlation functions of the complete code of binary spread spectrum phase-shift keyed signals with polarization coding were found in the form of the related distribution series. The analytic expressions for the n-th order of presented values of these functions for the complete code of the specified signals were assigned. The calculation example for the distribution series of presented values of aperiodic and periodic correlation functions for the complete code of the specified signals with the length of vector code sequences N=4 was given. The values of the relative frequencies of the correlation functions values for this case were found by the means of direct computing and their exact match with the corresponding predicted probability values was demonstrated. The approximations of the accurate distribution laws were given: for periodic correlation functions case – by Gaussian probability density, and for the aperiodic functions case – by the Pearson curve of VII type. Practical relevance. The found accurate laws for presented values of aperiodic and periodic correlation functions of the complete code of binary spread spectrum phase-shift keyed signals with polarization coding and their approximations allow to assess the correlation properties of large systems of such signals.

Dynamic Perviousness: A Novel Imaging Marker for Predicting Mechanical Thrombectomy Outcomes in Acute Ischemic Stroke.

The predictive value of thrombus standard perviousness (SP) in acute ischemic stroke (AIS) for the technical success rates of mechanical thrombectomy (MT) or functional outcomes is not yet conclusive. We investigated the relationship between dynamic perviousness (DP) and revascularization results using time-dependent enhancement curve types determined with computed tomography (CT). A retrospective analysis of 137 AIS patients was performed. DP was calculated as the thrombus attenuation increase (TAI) using three time points and categorized into four groups: (1) no enhancement (CNE); (2) late enhancement (CLE); (3) early enhancement with washout (CW); (4) early enhancement without washout (CNW). Associations with the technical success rate and functional outcomes were assessed. Late enhancement (CLE) had approximately two times higher odds for successful MT as compared to clots with other enhancement dynamics. The odds ratios (logistic regression model with CNW as the reference) for the TICI III scores were 4.04 (p = 0.067), 1.82 (p = 0.3), and 1.69 (p = 0.4) for CLE, CW, and CNE, respectively. The NIHSS scores at discharge and mRS scores at three months showed regression coefficients (linear regression model with CNW as reference) of -3.05 (p = 0.10), -1.17 (p = 0.51), and -1.24 (p = 0.47); and -1.30 (p = 0.097), -0.85 (p = 0.25), and -0.15 (p = 0.83) for CLE, CW, and CNE, respectively. Thrombi with late enhancement patterns showed a higher revascularization rate and better outcomes as compared to clots with early uptake or no washout.

Traffic safety comprehensive evaluation of urban tunnel visual guiding system based on extension matter-element model: a case study in tunnel curves

Objective The visual guiding system, as a tunnel traffic safety improvement method by using visual guiding facilities to actively guide driving safely, has been widely used in countries with many tunnels, in recent years. This paper aims to quantitatively study the comprehensive evaluation of traffic safety of the visual guiding system in tunnels, which has certain engineering application value and can provide support for the quantitative evaluation and optimal design of tunnel traffic safety. Methods Based on the analysis of the relevant factors of urban tunnel traffic safety, a multi-factor comprehensive evaluation system with 5 upper-level indicators and 12 basic-level indicators was proposed. Considering the independent and incompatible indicators, a comprehensive evaluation method of traffic safety of the visual guiding system in urban tunnels was constructed by using the extension matter-element model. Taking the scene of 4 types of tunnel curves, such as no facilities, horizontal stripe, chevron alignment sign, and LED arch, as examples, the comprehensive evaluation of various schemes were carried out by using simulation tests. Results The traffic safety comprehensive evaluation system of visual guiding system in urban tunnels can be analyzed from five aspects: perception reaction, guidance ability, driver factor, driving task, and facility appearance. The results demonstrated significant the comprehensive evaluation result of the target level of scene 1 was L4, scene 2 was L3, scene 3 was L2, and scene 4 was L1. That is, the final results of the comprehensive evaluation of the four scenes were poor, medium, good, and very good, respectively. Conclusions In the scheme of visual guiding system for urban tunnel curves, the effectiveness of the three types of designs, from high to low, was the LED arch, chevron alignment sign, and horizontal stripe, and the safety of the scene without facilities was the lowest. Hence, setting the LED arch in the urban tunnel curve has a good effect in the aspects of guidance ability, sight distance, and sight zone, and is conducive to the driver’s perception reaction and driving task.