Matching Design Research Articles

A 23–29.5 GHz three‐stage mm‐wave GaN power amplifier using arbitrary two‐port complex‐impedance matching method

SummaryThis paper presents a broadband monolithic millimeter‐wave integrated circuit GaN power amplifier (PA) with arbitrary two‐port complex‐impedance matching method. The proposed matching topology has been applied to interstage matching network design by modifying traditional coupling matrix and synthesizing a desired network. The optimum load traction technique is introduced to provide some more suitable Zopts. After continuous‐wave test, the three‐stage MMIC PA achieves a peak PAE of 39.1% with a 34.9 dBm output power from 23 to 29.5 GHz and the measured S21 is 32.5 dB with a ±2.5 dB gain variation. When driven by a 400 MHz OFDM modulation signal with a PAPR of 8.5 dB, the measured ACPR is improved to −40.6/−40.7 dBc with DPD. In this case, the PA achieves an average PAE of 11.7% and a 26.7 dBm average output power.

An Electromechanical Matching Design Method for Faceted Surface of Mesh Reflector

The faceted surface is used in mesh reflectors to reflect electromagnetic (EM) signals. The matching design method of surface geometry is developed by considering EM performance. The geometrical model of faceted surface is established to avoid the facets overlap by using the force density method, and the far-field scattered by mesh reflector is derived to reveal the relationship between the faceted surface and EM performance. To improve the computational efficiency, the double integral of the far-field is derived in a closed-form expression, and a refinement procedure of EM grids for facets is proposed to homogenize the grids. The electromechanical coupling optimization model is established, and the comparative analysis is carried out, respectively. Numerical results show that the proposed method can obtain the higher gain with a larger surface error of the mesh reflector by adjusting the distribution of the surface faceted error.

The penetration performance and matching design method of tandem warhead against ultra-high strength concrete

The penetration performance of the tandem warhead against ultra-high strength concrete and the matching relationship between the precursor shaped charge and the following kinetic energy warhead of the tandem warhead are researched to enhance the damage effect. For the precursor shaped charge, the formation and penetration properties of jet are studied in a combined experimental and numerical way. The value of kinetic energy/target borehole volume of C130 ultra-high strength concrete under the penetration of titanium alloy jet is obtained and the relationship of the depth and diameter of the precursory penetrating cavity is developed. For the following kinetic energy warhead, the numerical simulation of penetrating the pre-damage C130 ultra-high strength concrete is carried out and significant influence of the pre-damage crater’s depth and diameter on the relay penetration depth is observed. The matching method for the pre-damage crater resulting from the precursor shaped charge and the follow-through depth of the following kinetic energy warhead is set up on the basis of obtained penetration rules of two stages, which could provide helpful reference for the preliminary fast design of tandem warhead against ultra-high strength concrete.

SARS-CoV-2 pandemic as a model to assess the relationship between intercurrent viral infections and disease activity in Multiple Sclerosis: A propensity score matched case-control study.

An association between intercurrent viral respiratory infections and exacerbations of Multiple Sclerosis (MS) disease activity has been proposed by several studies. Considering the rapid spread of SARS-CoV2 worldwide and the systematic effort to immediately detect all incident cases with specific diagnostic tests, the pandemic can represent an interesting experimental model to assess the relationship between viral respiratory infections and MS disease activity. In this study, we have performed a propensity score matched case-control study with a prospective clinical/MRI follow-up, on a cohort of relapsing-remitting MS (RRMS) patients who tested positive for SARS-CoV2 in the period 2020-2022, with the aim to evaluate if the SARS-CoV2 infection influences the short-term risk of disease activity. Controls (RRMS patients not exposed to SARS-CoV-2, using 2019 as the reference period) were matched 1:1 with cases for age, EDSS, sex and disease-modifying treatment (DMT) (moderate efficacy vs high efficacy). Differences in relapses, MRI disease activity and confirmed disabilty worsening (CDW) between cases in the 6 months following the SARS-CoV-2 infection, and controls in a similar 6 months reference period in 2019 were compared. We identified 150 cases of SARS-CoV2 infection in the period March 2020 - March 2022, out of a total population of approximately 1500 MS patients, matched with 150 MS patients not exposed to SARS-CoV2 (controls). Mean age was 40.9±12.0 years in cases and 42.0±10.9 years in controls, mean EDSS was 2.54±1.36 in cases and 2.60±1.32 in controls. All patients were treated with a DMT, and a considerable proportion with a high efficacy DMT (65.3% in cases and 66% in controls), reflecting a typical real world RRMS population. 52.8% of patients in this cohort had been vaccinated with a mRNA Covid-19 vaccine. We did not observe a significant difference in relapses (4.0% cases, 5.3% controls; p=0.774), MRI disease activity (9.3% cases, 8.0% controls; p=0.838), CDW (5.3% cases, 6.7% controls; p=0.782) in the 6 months after SARS-CoV-2 infection between cases and controls. Using a propensity score matching design and including both clinical and MRI data, this study does not suggest an increased risk of MS disease activity following SARS-CoV-2 infection. All MS patients in this cohort were treated with a DMT, and a considerable number with a high efficacy DMT. These results therefore may not be applicable to untreated patients, for which the risk of increased MS disease activity after SARS-CoV-2 infection may not be excluded. A possible hypothesis explaining these results could be that SARS-CoV2 is less prone, compared to other viruses, to induce exacerbations of MS disease activity; another possible interpretation of these data might be that DMT is able to effectively suppress the increase of disease activity triggered by SARS-CoV2 infection.

Study on the influence of barrel venting on the overload waveform of projectile in bore

In order to evaluate the anti shock overload ability of electronic components and parts in explosive device launcher, half sine wave generator with certain amplitude and pulse width is often used to verify it. In this paper, gun launcher is used as the shock wave generator. Different charge structures are studied for the interior ballistics process of barrel with or without venting according to certain requirements of mechanical overload. The influence of different charge structure, chamber volume and vent hole size on the overload waveform of projectile in the process of interior ballistic is studied by numerical simulation. The simulation results show that the larger the vent diameter is, the closer it is to the standard waveform. The research results can provide references for the matching design of projectile and artillery, the research and development of intelligent ammunition and the assessment. The research results can provide for the matching design of new artillery projectile and artillery and the research and development of intelligent ammunition.

Research on fast matching method of suspension stiffness and damping based on unmanned special vehicle

At present, the domestic research on the matching of stiffness and damping of the suspension system of unmanned special vehicles mainly adopts the empirical method and experimental method. This method is time-consuming and laborious, which prolongs the development cycle of unmanned special vehicles. In order to improve the vehicle ride comfort and reduce the research and development time, based on the single wheel two degree of freedom driving vibration model, this paper analyzes the influence of suspension stiffness and damping on the acceleration response of vehicle body, deduces the general calculation formulas of acceleration, suspension dynamic deflection and root mean square value of wheel dynamic load, and establishes the mathematical model of the optimal damping ratio of suspension system based on driving safety and comfort, The damping ratio design of the suspension system of an unmanned special vehicle is completed. The results show that this method can quickly and accurately complete the stiffness and damping matching design of suspension system, and shorten the time of vehicle design and development.

Research on the Mechanism and Path of Rural Industry Revitalization Enabled by Digital Economy in Southwest China

Establishing a long-term mechanism for empowering rural industry revitalization through the digital economy is the key to comprehensively promoting rural revitalization during the 14th Five Year Plan period. This article analyzes the influencing factors and characteristics of different models of rural industry development in the southwest region, and identifies specific models that can match the digital economy’s empowerment of different industries in the southwest region. And from the perspective of supply side structural reform, the research on the development mechanism and implementation path of rural industry revitalization in Southwest China is placed under the national strategy of digital economy, aiming to provide scientific decision-making basis for the matching mode, mechanism design, and implementation path in the process of rural industry revitalization in Southwest China from the perspective of supply side structural reform.

Evolocumab attenuate pericoronary adipose tissue density via reduction of lipoprotein(a) in type 2 diabetes mellitus: a serial follow-up CCTA study

BackgroundPericoronary adipose tissue (PCAT) density is a biomarker of vessel inflammation, which is supposed to be increased in patients with type 2 diabetes mellitus (T2DM). However, whether the coronary inflammation revealed by this novel index could be alleviated after evolocumab treatment in T2DM remains unknown.MethodsFrom January 2020 to December 2022, consecutive T2DM patients with low-density lipoprotein cholesterol ≥ 70 mg/dL on maximally tolerated statin and taking evolocumab were prospectively included. In addition, patients with T2DM who were taking statin alone were recruited as control group. The eligible patients underwent baseline and follow-up coronary CT angiography with an interval of 48-week. To render patients with evolocumab as comparable to those controls, a propensity-score matching design was used to select the matched pairs with a 1:1 ratio. Obstructive lesion was defined as the extent of coronary artery stenosis ≥ 50%; the numbers inside the brackets were interquartile ranges.ResultsA total of 170 T2DM patients with stable chest pain were included [(mean age 64 ± 10.6 [range 40–85] years; 131 men). Among those patients, 85 were in evolocumab group and 85 were in control group. During follow-up, low-density lipoprotein cholesterol (LDL-C) level (2.02 [1.26, 2.78] vs. 3.34 [2.53, 4.14], p < 0.001), and lipoprotein(a) (12.1 [5.6, 21.8] vs. 18.9 [13.2, 27.2], p = 0.002) were reduced after evolocumab treatment. The prevalence of obstructive lesions and high-risk plaque features were significantly decreased (p < 0.05 for all). Furthermore, the calcified plaque volume were significantly increased (188.3 [115.7, 361.0] vs. 129.3 [59.5, 238.3], p = 0.015), while the noncalcified plaque volume and necrotic volume were diminished (107.5 [40.6, 180.6] vs. 125.0 [65.3, 269.7], p = 0.038; 0 [0, 4.7] vs. 0 [0, 13.4], p < 0.001, respectively). In addition, PCAT density of right coronary artery was significantly attenuated in evolocumab group (− 85.0 [− 89.0, − 82.0] vs. − 79.0 [− 83.5, − 74.0], p < 0.001). The change in the calcified plaque volume inversely correlated with achieved LDL-C level (r = − 0.31, p < 0.001) and lipoprotein(a) level (r = − 0.33, p < 0.001). Both the changes of noncalcified plaque volume and necrotic volume were positively correlated with achieved LDL-C level and Lp(a) (p < 0.001 for all). However, the change of PCATRCA density only positively correlated with achieved lipoprotein(a) level (r = 0.51, p < 0.001). Causal mediation analysis revealed Lp(a) level mediated 69.8% (p < 0.001) for the relationship between evolocumab and changes of PCATRCA.ConclusionsIn patients with T2DM, evolocumab is an effective therapy to decrease noncalcified plaque volume necrotic volume, and increase calcified plaque volume. Furthermore, evolocumab could attenuate PCAT density, at least in part, via the reduction of lipoprotein(a).

Application Research of PVT in Solar House R-CELLS

The application of PVT (Photovoltaic-thermal) technology is discussed based on R-CELLS, which is a zero-energy solar energy house at Solar Decathlon China 2021. Combined with the actual data, the simulation model of the PVT system, which supplies domestic hot water and heating bathroom, is established in TRNSYS, and the performance evaluation of the whole year and heating season and economic analysis of the whole life cycle is carried out at the same time. Comparing and analyzing the system with or without auxiliary heating in the water tank, the simulation results show that the annual average electrical efficiency of the system is 15.35% and 15.52%, the annual average thermal efficiency is 3.36% and 9.52%, and the payback period is 13.87 years and 12.12 years. By increasing the number of PVT panels, 4 PVT panels can achieve zero energy consumption of the system, and the payback period of the PVT system can be reduced to 6.5 years after continuing to increase. The small-scale PVT system is systematically analyzed based on a case, and the importance of water tank auxiliary heating design and supply-demand matching design in the PVT energy supply system is found through data comparison, which has reference significance for the promotion of PVT building energy supply system in the future.

Improved texture and magnetic properties in thin-gauge strip-cast non-oriented electrical steel through matching design of hot-cold rolling

In this study, an optimized matching design of hot rolling and one-stage cold rolling was adopted to prepare thin-gauge strip-cast non-oriented electrical steel. The microstructure and texture evolution of the whole processing process were studied. The results indicated that the deformed microstructure after direct cold rolling was dominated by fibrous bands, and the annealed sheet exhibited strong γ-fiber and {114}<841> texture. However, after introducing appropriate hot rolling with reduction of 40–55%, the shear bands substructure in the cold rolled sheet were effectively increased. The unfavorable γ-fiber texture in the annealed sheets was weakened, and the favorable Goss texture was significantly enhanced. In addition, compared to direct cold rolling, the combined processing of hot rolling and cold rolling reduced the dislocation density of the cold rolled microstructure, resulting in the increase in the average grain size of annealed microstructure. Moreover, the homogeneity of microstructure was improved. Finally, the magnetic properties of the thin-gauge non-oriented electrical steel were significantly improved.

The Association Between COVID-19 and Febrile Seizure: A Retrospective Case-Control Study.

Throughout the pandemic, febrile seizures have resulted from infection secondary to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The objective of this study is to determine if there is an increased association between COVID-19 and febrile seizures as compared with other causes of febrile seizures. This was a retrospective case control study. Data were collected from the National Institute of Health (NIH) supported National COVID Cohort Collaborative (N3C). Patients from 6 to 60 months who were tested for COVID-19 were included; cases were defined as COVID-19-positive patients whereas controls were defined as COVID-19-negative patients. Febrile seizures diagnosed within 48 hours of the COVID-19 test were considered to be associated with the test result. Patients were subjected to a stratified gender and date matching design followed by a logistic regression controlling for age and race. During the study period, 27,692 patients were included. Of those, 6923 patients were COVID-19-positive, among which 189 had febrile seizures (2.7%). After logistic regression, the likelihood of having febrile seizures concurrently with COVID-19 as compared with other causes was 0.96 ( P = 0.949; confidence interval, 0.81, 1.14). There were 2.7% of the patients with COVID-19 that were diagnosed with a febrile seizure. However, when subjected to a matched case control design with logistic regression controlling for confounding variables, there does not appear to be an increased risk of febrile seizures secondary to COVID-19 as compared with other causes.

Multi-Objective Optimization Design and Performance Comparison of Magnetorheological Torsional Vibration Absorbers of Different Configurations.

The purpose of this study is to provide a convenient optimization design method for magnetorheological torsional vibration absorbers (MR-TVA) suitable for automotive engines, which is a damper matching design method that takes into account the needs of the engine operating conditions. In this study, three kinds of MR-TVA with certain characteristics and applicability are proposed: axial single-coil configuration, axial multi-coil configuration and circumferential configuration. The magnetic circuit model, damping torque model and response time model of MR-TVA are established. Then, under the constraints of weight, size and inertia ratio, according to different torsional vibration conditions, the MR-TVA mass, damping torque and response time are multi-objective optimized in two directions. The optimal configurations of the three configurations are obtained from the intersection of the two optimal solutions, and the performance of the optimized MR-TVA is compared and analyzed. The results show that the axial multi-coil structure has large damping torque and the shortest response time (140 ms), which is suitable for complex working conditions. The damping torque of the axial single coil structure is generally large (207.05 N.m), which is suitable for heavy load conditions. The circumferential structure has a minimum mass (11.03 kg) and is suitable for light load conditions.

Research on configuration and performance of water ramjet pressurized water intake system

Water ramjet is the most ideal power propulsion device for high-speed underwater weapons. However, failure to start it at low-speed makes it hard for the engine to be widely used. In order to solve the problem of starting water ramjet at low-speed, a configuration scheme of water ramjet pressurized water intake system of the micro-turbine driving micro-mixed-flow pump is proposed. The design method of micro-turbine and micro-mixed-flow pump is perfected. And the simulation model of turbine and mixed-flow pump is established. The rationality of the design results was verified by numerical simulation. The matching design of the turbine and the mixed-flow pump is completed. And the working performance of the pressurized water inlet system is analyzed. The results show that the maximum relative deviation between the design results of the turbine and the pump and the target value is less than 3.2%, and the booster system can increase the fluid pressure by 2.0 MPa, reducing the starting speed of the ramjet from 90 to 63 m/s. The research results of this paper have reference value for the engineering application of water ramjet technology.

Far ultraviolet mirrors for aurora imaging: design and fabrication.

The emission lines of 140-180nm are auroral bands of N 2 Lyman-Birge-Hopfield, and they have been imaging targets of many satellites that need reflective mirrors. To obtain good imaging quality, the mirrors also should have excellent out-of-band reflection suppression as well as high reflectance at working wavelengths. We designed and fabricated non-periodic multilayer L a F 3/M g F 2 mirrors with working wave bands of 140-160nm and 160-180nm, respectively. We used a match design method and deep search method to design the multilayer. Our work has been utilized in the new wide-field auroral imager of China, and the application of these notch mirrors with excellent out-of-band suppression reduces the utilization of corresponding transmissive filters in the optical system of space payload. Furthermore, our work provides new routes for the design of other reflective mirrors in the far ultraviolet region.

Using a Data Mining Method to Explore Strategies for Improving the Social Interaction Environment Quality of Urban Neighborhood Open Spaces

With the intensification of population aging and the increasing awareness of public health protection in the post-epidemic era, the renewal of the old urban community neighborhood space is facing many new challenges and problems. Neighborhood Public Open Space (POS) is the main place for people to carry out various social activities in community life. The quality of the social interaction environment that a neighborhood POS can provide can have a vital impact on people’s well-being, as well as their physical and mental health. Therefore, the purpose of this research is to identify and clarify the key physical environmental design attributes/features of the old urban community neighborhood POS, and to explore the relationship between them from the perspective of creating a high-quality social environment. Through the investigation of relevant cases in Shenzhen and Guangzhou, China, the classification performance of each case on the key physical and environmental elements is used as the conditional attribute, and the quality of the social interaction environment in the current situation of each case is used as the decision making attribute to conduct a data mining analysis. Using rough set theory, this study screened out four important elements: greenbelt form planning (C1); ped and bike system (C2); space organization and zoning planning (C6); Public facilities (C8). Moreover, this study also presents a set of hierarchical decision rules to describe the classification status of the matching physical environmental design elements when the social interaction environment reaches a high quality in the neighborhood POS. This study provides local policy makers with key current situation assessment and diagnostic tools in urban-built environmental renewal projects. The results of this study can help designers draw up the renovation design plans of neighborhood POS on the basis of efficiently obtaining the practical experience of relevant cases, and then create a high-quality social interaction environment.

A Fast Design Method of Anisotropic Dielectric Lens for Vortex Electromagnetic Wave Based on Deep Learning

Orbital angular momentum (OAM) has made it possible to regulate classical waves in novel ways, which is more energy- or information-efficient than conventional plane wave technology. This work aims to realize the transition of antenna radiation mode through the rapid design of an anisotropic dielectric lens. The deep learning neural network (DNN) is used to train the electromagnetic properties of dielectric cell structures. Nine variable parameters for changing the dielectric unit structure are present in the input layer of the DNN network. The trained network can predict the transmission phase of the unit cell structure with greater than 98% accuracy within a specific range. Then, to build the corresponding relationship between the phase and the parameters, the gray wolf optimization algorithm is applied. In less than 0.3 s, the trained network can predict the transmission coefficients of the 31 × 31 unit structure in the arrays with great accuracy. Finally, we provide two examples of neural network-based rapid anisotropic dielectric lens design. Dielectric lenses produce the OAM modes +1, -1, and -1, +2 under TE and TM wave irradiation, respectively. This approach resolves the difficult phase matching and time-consuming design issues associated with producing a dielectric lens.

Surface matching error evaluation system design based on QT

Based on the analysis of existing assembly simulation positioning error evaluation methods, a visualization evaluation system of surface matching error was developed in this paper. The software can read the point cloud data measured by the CMM. And then, the software can fit the data to the surface and then visualize the surface. At the same time, the software can automatically match different parts in the database, display the best matching solution, and evaluate the matching error.

Abstract P5-03-13: Circular RNAs express heterogeneously across different breast cancer subtypes and correlate with invasive disease-free survival

Abstract Background: Circular RNAs (circRNAs) are a large class of RNAs derived from back splicing and subsequent circularization of precursor mRNAs. Due to their circular structures, circRNAs are protected from exonuclease-induced degradation and are thereby comparatively more stable than linear RNAs. circRNAs have been implicated in the progression of multiple types of cancers but few studies have systematically examined how circRNAs associate with different subtypes of breast cancer and prognosis. Methods: We conducted a nested case-control study of prospectively ascertained participants in the Chicago Multiethnic Breast Cancer Cohort (ChiMEC), in which patients without recurrence were matched with patients with recurrence on time to recurrence, age of diagnosis, tumor stage, and clinical subtype. We performed whole exome capture RNA sequencing on tumor samples that passed quality control. We then used CIRIquant to identify circRNAs by aligning back-splice junction (BSJ) reads to pseudo-circular reference sequences and retained circRNAs that had a BSJ read count of 2 or greater in at least 5 patients. After normalization using the trimmed mean of M-values method, we used edgeR to model circRNA expression via a negative binomial distribution and performed differential expression (DE) analyses of circRNAs by ER and HER2 status, as well as between Black (self-reported) and White patients. Furthermore, we conducted survival analyses for each circRNA using Cox proportional hazards models to assess how the expression of each circRNA associated with survival outcomes of invasive disease-free survival (IDFS) and overall survival, while adjusting for age at diagnosis, stage, and HER2 status. Results: A total of 123 of 126 sequenced patients were included in the analysis, including 56 Black patients, 59 White patients, and 8 patients from other racial groups. The mean age of diagnosis was 51.9 years of age (SD 13.2) with 68% ER+, 48% PR+, and 30% HER2+ patients. We identified 16,927 high-confidence circRNAs. In the crude DE analysis, we found 489 circRNAs differentially expressed between patients with ER+ compared to patients with ER- tumors and 33 circRNAs between HER2+ vs. HER2- at a false discovery rate of 0.05. After adjusting for race and grade, we discovered 187 circRNAs differentially expressed by ER status and 38 by HER2 status. In the DE analysis by race, we found 88 circRNAs that were differentially expressed between Blacks and Whites. After adjusting for grade, ER, PR, and HER2 status, 14 circRNAs remained significantly different between racial groups. After a median of follow up of 8 years, 41 patients died, 41 patients had invasive recurrent diseases, and 2 patients had second primary breast cancers, for a total of 57 events in the IDFS analysis. Because of the matching study design to limit the impact of known prognostic factors, none of known prognostic factors (stage, ER, PR, HER2, grade, and race) were statistically associated with IDFS. In the survival analyses, we discovered two circRNAs (hsa-GSK3B_0001 and hsa-CMPK1_0006) that met the Bonferroni threshold for significance for their associations with IDFS but did not detect any circRNAs that were significantly associated with overall survival after correction for multiple testing. Discussion: This preliminary study demonstrates that multiple candidate circRNAs were differentially expressed between BC subtypes and racial groups, and several circRNAs were associated with IDFS. Future studies are warranted to validate our findings and cement the portability of these circRNAs as prognostic biomarkers across populations. Citation Format: James L. Li, Toshio F. Yoshimatsu, Julian C. McClellan, Fangyuan Zhao, Yonglan Zheng, Olufunmilayo I. Olopade, Dezheng Huo. Circular RNAs express heterogeneously across different breast cancer subtypes and correlate with invasive disease-free survival [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-03-13.

Development of rejuvenator using waste vegetable oil and its influence on pavement performance of asphalt binder under ultraviolet aging

With the development of road engineering, the shortage of resources and road damage are becoming increasingly serious. In this research, The regeneration effect of a rejuvenator on the ultraviolet (UV)-aged asphalt is tested. The rejuvenator is composed of base oil, plasticizer, toughener and petroleum resin. The recovery performance of aged asphalt inareas with strong UV light is compared using indoor asphalt aging tests. A representative UV aged asphalt is selected for experiments. The basic performance of regenerated asphalt with the mixed ratio of different materials is measured using penetration, softening point, and ductility tests. The orthogonal test design (OTD) and analytic hierarchy process (AHP) model are established, and the optimal match design of a rejuvenator is obtained. The performance of UV aged asphalt before and after regeneration is tested by dynamic shear rheology (DSR) and the Fourier Transform Infrared Spectroscopy (FTIR) test. The results show a strong link between the asphalt from the areas with intense UV light and the asphalt after indoor 50 h UV aging. Waste vegetable oil (WVO) is selected as the base oil for the rejuvenator. The proportion of plasticizer in the WVO was determined to 30% based on OTD-AHP model optimization, the toughening agent is 4%, and petroleum resin is 9%. The high-temperature performance of asphalt can be improved with a reasonable regenerative agent dosage. The FTIR test shows that the rejuvenator can dilute carbonyl and sulfoxide groups in aged asphalt, soften asphalt and restore asphalt pavement performance. The results of this study can be applied to the asphalt regeneration to provide road remediation measures for asphalt deterioration in high UV areas.

Prediabetes as a risk factor for new-onset atrial fibrillation: the propensity-score matching cohort analyzed using the Cox regression model coupled with the random survival forest

BackgroundThe glycemic continuum often indicates a gradual decline in insulin sensitivity leading to an increase in glucose levels. Although prediabetes is an established risk factor for both macrovascular and microvascular diseases, whether prediabetes is independently associated with the risk of developing atrial fibrillation (AF), particularly the occurrence time, has not been well studied using a high-quality research design in combination with statistical machine-learning algorithms.MethodsUsing data available from electronic medical records collected from the National Taiwan University Hospital, a tertiary medical center in Taiwan, we conducted a retrospective cohort study consisting 174,835 adult patients between 2014 and 2019 to investigate the relationship between prediabetes and AF. To render patients with prediabetes as comparable to those with normal glucose test, a propensity-score matching design was used to select the matched pairs of two groups with a 1:1 ratio. The Kaplan–Meier method was used to compare the cumulative risk of AF between prediabetes and normal glucose test using log-rank test. The multivariable Cox regression model was employed to estimate adjusted hazard ratio (HR) for prediabetes versus normal glucose test by stratifying three levels of glycosylated hemoglobin (HbA1c). The machine-learning algorithm using the random survival forest (RSF) method was further used to identify the importance of clinical factors associated with AF in patients with prediabetes.ResultsA sample of 14,309 pairs of patients with prediabetes and normal glucose test result were selected. The incidence of AF was 11.6 cases per 1000 person-years during a median follow-up period of 47.1 months. The Kaplan–Meier analysis revealed that the risk of AF was significantly higher in patients with prediabetes (log-rank p < 0.001). The multivariable Cox regression model indicated that prediabetes was independently associated with a significant increased risk of AF (HR 1.24, 95% confidence interval 1.11–1.39, p < 0.001), particularly for patients with HbA1c above 5.5%. The RSF method identified elevated N-terminal natriuretic peptide and altered left heart structure as the two most important risk factors for AF among patients with prediabetes.ConclusionsOur study found that prediabetes is independently associated with a higher risk of AF. Furthermore, alterations in left heart structure make a significant contribution to this elevated risk, and these structural changes may begin during the prediabetes stage.