In the era of multi-messenger astronomy, gamma-ray bursts (GRBs) with known redshifts, especially high-redshift GRBs, are a powerful tool for studying the structure and evolution of the early ...Universe. We review the background, the history, and the application of measurement methods of GRB redshifts in astronomy. Based on different observation targets, two measurement methods are mainly introduced. One is on GRB afterglow, the other is on GRB host galaxy. There are various processing methods belonging to measurement methods based on afterglow, including spectral measurement method of afterglow and afterglow spectral energy distribution fitting method with improved methods. There are also numerous measurement methods based on host galaxy, such as spectral measurement method of host galaxy, template matching method of host galaxy, some automatic spectroscopic redshift measurement methods, and machine learning methods. We subsequently introduce the principles, effects, and performance of these methods. We enumerate several detection and measurement instruments, which have been used in observation. The characteristics, advantages, disadvantages, and applicability of the GRB redshift measurement methods are summarized and analyzed. Furthermore, we provide a data set of 611 GRBs with measured redshift. The data set has been collected since 1997. Analysis and statistics are presented based on this data set. We summarize the characteristics of GRBs such as location, time, and accuracy. Finally, we introduce Space-based multi-band astronomical Variable Objects Monitor (SVOM) mission dedicated to searching high redshift GRBs. We also introduce the application prospect of various redshift measurement methods in SVOM mission.
In order to explore the types of diagenesis in Sudeerte area, through core and thin slice identification, it is clear that the Xing’anling oil layer is mainly affected by compaction, cementation, ...andrecrystallization. The compaction is mainly early compaction, late pressure dissolution is not obvious; cementation presents two forms of crystalline quartz and amorphous opal; recrystallization is manifested as the conversion process of opal t-ochalcedony quartz.
Heat treatment is widely used in food industry. Proteins and polysaccharides as important natural polymers in food, under heat treatment, the interactions between them could mediate the conformation ...and functional properties of proteins. Thermally induced β‐lactoglobulin‐gum arabic complexes (β‐Lg‐GA) were fabricated, and the effect of heat treatment on physicochemical properties of the complexes was systematically investigated. The average particle size of β‐Lg‐GA complexes decreased with temperature increased, at 85°C, a smaller size of 273 nm was obtained. A saturated adsorption of GA was found when mass ratio of β‐Lg/GA was <1:2. At pH = 4.2–7.0, electrostatic attraction between β‐Lg and GA was low and a fairly constant turbidity was observed, the formed composite particles had good stability to the pH value. Through UV, fluorescence, and FTIR spectroscopy, it was found that formation of the nanoparticles relied on thermal denaturation and aggregation of protein, the electrostatic, hydrophobic, and hydrogen bonding interactions between β‐Lg and GA were also important. Scanning electron microscope further indicated β‐Lg and GA had good compatibility, and the complexes had a spherical core–shell structure at molecular level. In addition, these prepared natural nanoparticles by heat treatment show significantly higher encapsulation efficiency for (‐)‐epigallocatechin‐3‐gallate (EGCG) than that of unheated, thus could be used as a promising carrier for biologically active substances.
Novel thermally induced β‐lactoglobulin‐gum arabic complexes (β‐Lg‐GA) were fabricated. A preferable size of 273 nm was obtained at 85°C. And our findings indicated that heating not only denatured β‐Lg, but also promoted structural rearrangement of β‐Lg and GA to form a more stable core‐shell structure. Moreover these prepared natural nanoparticles by heat treatment show significantly higher encapsulation efficiency for (‐)‐epigallocatechin‐3‐gallate (EGCG) than that of unheated, thus could be used as a promising carrier for biologically active substances.
A low-cost contact scanning microscope is presented which performs optical imaging of millimeter-scale samples with multiple sensory modalities at a spatial resolution better than the pixel size in ...both x and y dimensions. The 7.5 mm <inline-formula><tex-math notation="LaTeX">\times</tex-math></inline-formula> 3.2 mm 0.35 <inline-formula><tex-math notation="LaTeX">\mu</tex-math></inline-formula>m CMOS image sensor is comprised of 214 scanning lines of 256 pixels, each line horizontally shifted by 300 nm with respect to the adjacent lines. When scanning in the y dimension, this results in a staircase-like staggered-pixels organization with an effective spatial resolution in the x dimension of less than the pixel size, with a theoretical limit of 300 nm, subject to the light diffraction limit and to photodiode size-dependent spatial aliasing. The height of the resulting pixel "staircases" is capped at 2.5 mm by wrapping the 215th row back to the first row, yielding an approximately 2 mm <inline-formula><tex-math notation="LaTeX">\times</tex-math> </inline-formula> 2.5 mm instantaneous scanning window size. The spatial resolution in the y dimension is set by the sample scanning rate and the frame rate, subject to the same limitations. Integration of multiple scanning lines naturally lends itself to the inclusion of multiple sensory modalities, with five modalities included as an example: High-resolution (up to 300 nm), fluorescence-sensitive, and triple-orientation light polarization-sensitive pixels. The resulting modified scanning pattern is digitized by on-chip column-parallel 2nd order Delta-Sigma ADCs with ENOB of 9.1 and is reconstructed into a full-resolution image in software. Experimental measurements, where contact-scanning is emulated by the sample image moving on an LCD monitor and projected through a lens, support the validity of the presented concept.
The progressive iterative approximation (PIA) is a versatile method for interpolating or fitting a given data set. The convergence behavior of PIA plays a pivotal role in determining the ...computational efficiency of data interpolation or fitting. This paper introduces an accelerated iterative approach, GS-PIA, derived from the Gauss-Seidel splitting, specifically designed for interpolating data points. The convergence and computational cost of the proposed iterative method are discussed. Numerical results underscore the superiority of GS-PIA in data interpolation when compared to other existing methods.
To improve the computational efficiency of data interpolation, we have exploited the diagonally compensated splitting iteration for the collocation matrix equation. The proposed splitting iteration ...is the matrix form of the preconditioned progressive iterative approximation (PPIA). Therefore, the proposed iteration format is convergent. Moreover, the proposed iteration involves only BLAS-3 operations, and we can expect that the proposed iteration would perform better than the PPIA regarding computational efficiency. The numerical results also show that the proposed splitting iteration outperforms the PPIA regarding computational time and stability.
Zein as a kind of carrier material has attracted extensive interest, while the interaction mechanism between zein and nutrients is still elusive. In this work, the binding mechanism of zein with ...epigallocatechin-3-gallate (EGCG) was investigated via multi-spectroscopy and molecular dynamics (MD) simulation. The quenching of zein by EGCG is mainly static quenching, and the secondary structure of zein is slightly changed after the binding of EGCG to zein. The formation of Zein-EGCG complexes was confirmed by ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Molecular dynamics (MD) simulation clarified that the EGCG prefers to bind to the pocket of zein formed by residues Y171, Q174, L176 and L205. Electrostatic and van der Waals interactions played a dominant role for the binding of EGCG to zein, which was consistent with the results by fourier transform infrared spectroscopy (FTIR) and thermodynamic analysis. This study provides new insights into the interaction mechanism between zein and EGCG, which is very important to develop plant protein as tea polyphenol delivery system.
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•Interaction mechanism between zein and EGCG was studied.•The quenching of zein by EGCG is mainly static quenching.•The formation of Zein-EGCG complexes was confirmed.•The van der Waals and electrostatic interactions played an important role in binding of EGCG to zein.
In this paper, we aim to improve the order of the continuity to smooth two connected Bézier curves and surfaces when they satisfy lower-order continuity. It is necessary to adjust their control ...points to smooth two connected Bézier curves and surfaces. Because each adjusted control point is always expected not to be far from the original position, we use the approximate distance functions to optimize the control points that need to be changed. Based on solving bi-objective minimizations, we give the methods for smoothing two connected Bézier curves from Cr-1 to Cr (r=1, 2). Then we extend the approaches to the cases of surfaces, which include smoothing two connected Bézier surfaces in the u direction, in the u and v, and in the v direction. Some numerical examples show that the proposed methods are effective and easy to implement, so they can be used to smooth complex curves and surfaces connected by Bézier curves and surfaces.
Vibrio parahaemolyticus is a major cause of seafood-associated food poisoning. It is of great significance to develop an accurate, simple and cost-effective method to identify infected seafood, ...especially for on-site application. Polymerase chain reaction (PCR) remains the golden standard for nucleic acid detection. But traditional methods heavily reply on sophisticated instrument and specialized operators, which limits the application for on-site detections. Here we developed a novel, specific and visualized detection method for PCR based on CRISPR/Cas12a system. On a low-cost thermal cycler, amplification reaction can be conducted easily. The CRISPR/Cas12a system was specifically designed to evaluate amplicons, eliminating false positive results. Besides the negative samples remained colorless, the positive samples generated obvious green fluorescence, which could be easily distinguished by the naked eye using a homemade UV device. The presented detection method was verified by detecting shrimp samples. The limit of detection is 1.02 × 102 copies/μL. This presented method provided a new strategy for specific endpoint detection of PCR and advanced its application in field for food safety assurance.
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•CRISPR/Cas12a system was first used in PCR to develop a method for visualized detection of Vibrio parahaemolyticus.•CRISPR/Cas12a assisted PCR can be carried out by using a mini thermal cycler, having the potential for on-site application.•Amplicons can be specifically identified by the naked eye under UV light in 5 min.•Carryover contamination can be eliminated by requiring no uncapping operation and substituting dUTP for dTTP in PCR system.
In this paper, we propose a preconditioned progressive iterative approximation for triangular Bézier patches. Firstly, the diagonally compensated reduction is used in designing the preconditioner. ...Some properties of the preconditioner are shown. The validity of the presented iterative method by using LU factorization of the preconditioner is discussed. Then the preconditioned progressive iterative approximation is used to approximate rational triangular Bézier patches. The given numerical examples show that the proposed method achieves a great improvement on the convergence rate compared to the existing progressive iterative approximation.
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