62 research outputs found
Traveling Wave Solution to Two-Dimensional Burgers-Korteweg-De Vries Equation
In this thesis, we study the Two-Dimensional Burgers-Korteweg-de Vries (2D-BKdV) equation by analyzing the equivalent Abel equation, which indicates that under some particular conditions, the 2D-BKdV equation has a unique bounded traveling wave solution. By using the theorem of contractive mapping, a traveling wave solution to the 2D-BKdV equation is expressed explicitly. In the end, the behavior of the proper solution of the 2D-BKdV equation is established by applying the comparison theorem of differential equations
Socioeconomic inequalities in human papillomavirus knowledge and vaccine uptake: evidence from a cross-sectional study in China
ObjectiveProviding the human papillomavirus (HPV) vaccine is effective to eliminate the disparity in HPV-related cancers. It is unknown regarding inequality in the distribution of HPV vaccination in China since the vaccine was licensed and approved for use in 2016. This study aimed to examine socioeconomic inequalities in HPV-related knowledge and vaccination and identified factors associated with such inequalities.MethodsSelf-administered questionnaires measuring HPV-related knowledge and vaccine uptake were completed by 1,306 women through online survey platform. HPV knowledge was assessed using a 12-item question stem that covered the hazards of HPV infection, HPV vaccine dosage, benefits, and protection. Cluster analysis by combining monthly household income, educational level, and employment status was used to identify socioeconomic status (SES) class. The concentration index (CI) was employed as a measure of socioeconomic inequalities in HPV-related knowledge and vaccination. Linear regression and logistic regression were established to decompose the contributions of associated factors to the observed inequalities.ResultsThe CI for HPV-related knowledge and vaccine uptake was 0.0442 and 0.1485, respectively, indicating the higher knowledge and vaccination rate were concentrated in groups with high SES. Education and household income made the largest contribution to these inequalities. Age, residency and cervical cancer screening were also important contributors of observed inequalities.ConclusionSocioeconomic inequalities in HPV-related knowledge and vaccination uptake are evident in China. Interventions to diffuse HPV-related information for disadvantaged groups are helpful to reduce these inequalities. Providing low or no-cost HPV vaccination and ensuring accessibility of vaccines in rural areas are also considered to be beneficial
Halogen Bonding Increases the Potency and Isozyme-selectivity of Protein Arginine Deiminase 1 Inhibitors
Protein Arginine Deiminases (PADs) hydrolyze the side chain of arginine to form citrulline. Aberrant PAD activity is associated with rheumatoid arthritis, multiple sclerosis, lupus, and certain cancers. These pathologies established the PADs as therapeutic targets and multiple PAD inhibitors are known. Herein, we describe the first highly potent PAD1-selective inhibitors (1 and 19). Detailed structure-activity relationships indicate that their potency and selectivity is due to the formation of a halogen bond with PAD1. Importantly, these inhibitors inhibit histone H3 citrullination in HEK293TPAD1 cells and mouse zygotes with excellent potency. Based on this scaffold, we also developed a PAD1-selective activity-based probe that shows remarkable cellular efficacy and proteome selectivity. Based on their potency and selectivity we expect that 1 and 19 will be widely used chemical tools to understand PAD1 biology
Limitations and Improvements of the Intelligent Driver Model (IDM)
This contribution analyzes the widely used and well-known "intelligent driver
model" (briefly IDM), which is a second order car-following model governed by a
system of ordinary differential equations. Although this model was intensively
studied in recent years for properly capturing traffic phenomena and driver
braking behavior, a rigorous study of the well-posedness of solutions has, to
our knowledge, never been performed. First it is shown that, for a specific
class of initial data, the vehicles' velocities become negative or even diverge
to in finite time, both undesirable properties for a car-following
model. Various modifications of the IDM are then proposed in order to avoid
such ill-posedness. The theoretical remediation of the model, rather than post
facto by ad-hoc modification of code implementations, allows a more sound
numerical implementation and preservation of the model features. Indeed, to
avoid inconsistencies and ensure dynamics close to the one of the original
model, one may need to inspect and clean large input data, which may result
practically impossible for large-scale simulations. Although well-posedness
issues occur only for specific initial data, this may happen frequently when
different traffic scenarios are analyzed, and especially in presence of
lane-changing, on ramps and other network components as it is the case for most
commonly used micro-simulators. On the other side, it is shown that
well-posedness can be guaranteed by straight-forward improvements, such as
those obtained by slightly changing the acceleration to prevent the velocity
from becoming negative.Comment: 29 pages, 23 Figure
High-resolution myelin-water fraction and quantitative relaxation mapping using 3D ViSTa-MR fingerprinting
Purpose: This study aims to develop a high-resolution whole-brain
multi-parametric quantitative MRI approach for simultaneous mapping of
myelin-water fraction (MWF), T1, T2, and proton-density (PD), all within a
clinically feasible scan time.
Methods: We developed 3D ViSTa-MRF, which combined Visualization of Short
Transverse relaxation time component (ViSTa) technique with MR Fingerprinting
(MRF), to achieve high-fidelity whole-brain MWF and T1/T2/PD mapping on a
clinical 3T scanner. To achieve fast acquisition and memory-efficient
reconstruction, the ViSTa-MRF sequence leverages an optimized 3D
tiny-golden-angle-shuffling spiral-projection acquisition and joint
spatial-temporal subspace reconstruction with optimized preconditioning
algorithm. With the proposed ViSTa-MRF approach, high-fidelity direct MWF
mapping was achieved without a need for multi-compartment fitting that could
introduce bias and/or noise from additional assumptions or priors.
Results: The in-vivo results demonstrate the effectiveness of the proposed
acquisition and reconstruction framework to provide fast multi-parametric
mapping with high SNR and good quality. The in-vivo results of 1mm- and
0.66mm-iso datasets indicate that the MWF values measured by the proposed
method are consistent with standard ViSTa results that are 30x slower with
lower SNR. Furthermore, we applied the proposed method to enable 5-minute
whole-brain 1mm-iso assessment of MWF and T1/T2/PD mappings for infant brain
development and for post-mortem brain samples.
Conclusions: In this work, we have developed a 3D ViSTa-MRF technique that
enables the acquisition of whole-brain MWF, quantitative T1, T2, and PD maps at
1mm and 0.66mm isotropic resolution in 5 and 15 minutes, respectively. This
advancement allows for quantitative investigations of myelination changes in
the brain.Comment: 38 pages, 12 figures and 1 tabl
The succession of rhizosphere microbial community in the continuous cropping soil of tobacco
Introduction: Flue-cured tobacco is an important economic crop that is not tolerant of continuous cropping and can be influenced by planting soil conditions including rhizosphere microbial communities and soil physicochemical properties. The relationship between rhizosphere microbial communities and soil physicochemical properties under continuous cropping conditions is unclear.Methods: This study investigated the succession of rhizosphere microbial community in continuous tobacco cropping soil for 1, 3, 5, 8, 10, 15, and 30Â years. The physicochemical properties of the soil were measured, high-throughput sequencing was performed on the rhizosphere microbial community, and correlation analysis was conducted.Results: The results suggested that continuous cropping could significantly enrich soil available nitrogen, available phosphorus, available potassium, and organic matter. Meanwhile, the alpha diversity of the bacterial community was significantly reduced with continuous cropping, indicating significant changes in the structure of bacterial and fungal communities. Based on linear discriminant analysis effect size (LEfSe), 173 bacterial and 75 fungal genera were identified with significant differences. The bacterial genera, Sphingomonas, Streptomyces, and Microvirga, were significantly positively correlated with continuous cropping years. The fungal genera, Tausonia, Solicocozyma, Pseudomycohila, and Fusarium, also showed significant positive correlation with continuous cropping years. Meanwhile, the fungal genera, Olpidium, Cephaliophora, and Cercophora, presented an opposite correlation. However, there are differences in the correlation between these bacterial and fungal genera related to continuous cropping years and other different soil physicochemical properties.Discussion: In summary, this work could provide a reference for soil management and scientific fertilization of tobacco under continuous cropping conditions
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