Using restored two-dimensional X-ray images to reconstruct the three-dimensional magnetopause

Astronomical imaging technologies are basic tools for the exploration of the universe, providing basic data for the research of astronomy and space physics. The Soft X-ray Imager (SXI) carried by the Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) aims to capture two-dimensional (2-D) images of the Earth’s magnetosheath by using soft X-ray imaging. However, the observed 2-D images are affected by many noise factors, destroying the contained information, which is not conducive to the subsequent reconstruction of the three-dimensional (3-D) structure of the magnetopause. The analysis of SXI-simulated observation images shows that such damage cannot be evaluated with traditional restoration models. This makes it difficult to establish the mapping relationship between SXI-simulated observation images and target images by using mathematical models. We propose an image restoration algorithm for SXI-simulated observation images that can recover large-scale structure information on the magnetosphere. The idea is to train a patch estimator by selecting noise–clean patch pairs with the same distribution through the Classification–Expectation Maximization algorithm to achieve the restoration estimation of the SXI-simulated observation image, whose mapping relationship with the target image is established by the patch estimator. The Classification–Expectation Maximization algorithm is used to select multiple patch clusters with the same distribution and then train different patch estimators so as to improve the accuracy of the estimator. Experimental results showed that our image restoration algorithm is superior to other classical image restoration algorithms in the SXI-simulated observation image restoration task, according to the peak signal-to-noise ratio and structural similarity. The restoration results of SXI-simulated observation images are used in the tangent fitting approach and the computed tomography approach toward magnetospheric reconstruction techniques, significantly improving the reconstruction results. Hence, the proposed technology may be feasible for processing SXI-simulated observation images

Cross-cultural adaptation and validation of the Mental Health Quality of Life (MHQoL) questionnaire in a Chinese-speaking population with chronic musculoskeletal pain

Abstract Background The Mental Health Quality of Life (MHQoL) questionnaire is concise and suitable for rapid assessment of CMP (chronic musculoskeletal pain) patients in primary care. However, there is a lack of Chinese versions of the MHQoL. Objective To cross-culturally translate the MHQoL into Chinese and to assess its psychometric properties in Chinese-speaking patients with CMP. Methods The MHQoL was translated into Chinese according to the International Guidelines for the Cross-Cultural Adaptation of Self-Report Measures. 171 CMP patients were recruited to receive the Chinese versions of the MHQoL, SF-36, and HADS tests, and the MHQoL was retested seven days later. Result The Chinese version of MHQoL had good retest reliability (MHQoL-7D: ICC = 0.971; MHQoL-VAS: ICC = 0.988) and internal consistency (Cronbach’s alpha = 0.829). It showed a moderate correlation with the SF-36 total score (r=-0.509); the MHQoL-VAS moderately correlated with the Hospital Anxiety Depression Scale (r=-0.548). The MHQoL-7D showed no correlations with the SF-36’s PF (r=-0.083) and BP (r=-0.170), weak correlations with RP (r=-0.284), RE (r=-0.298), and SF (r=-0.380), and moderate-to-strong correlations with GH (r=-0.638), VT (r=-0.480), and MH (r=-0.632). Conclusion The Chinese version of the MHQoL can be used in clinical practice and research in Chinese-speaking CMP patients

STARR-seq identifies active, chromatin-masked, and dormant enhancers in pluripotent mouse embryonic stem cells

Contains fulltext : 224964.pdf (publisher's version ) (Open Access

Generation of 8–20 μm mid-infrared ultrashort femtosecond laser pulses via difference frequency generation

Abstract Mid-infrared (MIR) ultrashort laser pulses have a wide range of applications in the fields of environmental monitoring, laser medicine, food quality control, strong-field physics, attosecond science, and some other aspects. Recent years have seen great developments in MIR laser technologies. Traditional solid-state and fiber lasers focus on the research of the short-wavelength MIR region. However, due to the limitation of the gain medium, they still cannot cover the long-wavelength region from 8 to 20 µm. This paper summarizes the developments of 8–20 μm MIR ultrafast laser generation via difference frequency generation (DFG) and reviews related theoretical models. Finally, the feasibility of MIR power scaling by nonlinear-amplification DFG and methods for measuring the power of DFG-based MIR are analyzed from the author’s perspective

Multiple regulation over growth direction, band structure, and dimension of monolayer WS2 by a quartz substrate

A substrate plays a crucial role in controlled growth and property modulation of two-dimensional (2D) transition-metal dichalcogenides (TMDCs). In this work, we report multiple regulation over growth direction, band structure, and dimension of an epitaxial monolayer (1L) WS2 by an m-plane quartz substrate. The as-grown WS2 is oriented on a 2-fold symmetric m-quartz based on an anisotropic lattice match, which is distinct from that on c-sapphire. Owing to the large thermal expansion coefficient, the m-quartz generates a large compressive thermal strain in the as-grown WS2. By manipulating this thermal strain, the band structure of 1L-WS2 can be in situ regulated and a direct–indirect band gap transition occurs when the thermal strain exceeds 0.5%. Moreover, the unique atom distribution of the m-plane quartz established an anisotropic diffusion barrier for adlayer monomers which restricted the growth of WS2 uniaxially. By exploiting this, the dimension of WS2 can be tailored from a 2D triangle to a one-dimensional ribbon with controlled growth time. This work not only deepens the understanding of the relationship between a substrate and a material but also provides an effective way to directly regulate the as-grown TMDCs with desirable structures and properties