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X-ray detection plays a vital role in medical imaging, industrial defect detection, security screening and scientific research. Direct X-ray detectors are of greater interest to researchers because they offer the advantages of faster imaging, higher resolution and simpler construction than indirect detectors. Due to their intrinsic properties, traditional materials have inherent problems that limit their performance in detector applications. Perovskite is a new material with excellent properties that has great potential in the field of X-ray detectors. This paper summaries the research progress of perovskite materials in the field of X-ray detectors. First, the problems of traditional materials are listed according to the principle and material requirements of X-ray detectors. Then, the problems and challenges of different types of perovskite materials are divided from the classification of perovskite materials, from organic to inorganic materials, and from halide perovskites to lead-free perovskites. The intention is to provide ideas for the development of more environmentally friendly and higher-performance X-ray detectors. [ABSTRACT FROM AUTHOR]

Cs3Bi2I9 (CBI) is a promising material for direct X‐ray detectors. However, for the solution method, due to the difference in the chemical potential of Cs+, Bi3+, I− ions in the solvent, the composition of CBI single crystals (SCs) prepared by the solution method often deviates from the stoichiometric ratio, resulting in the formation of many defects in the material, which degrades the quality of the SC. Herein, Br− and Cl− are used as dopants to produce CBI SCs by the top seed solution method. It can be speculated that the dopant ions can reduce the VI defects in the CBI by means of density functional theory calculations. The carrier lifetimes of CBI SCs doped with Br− and Cl− have been increased to 41.7 and 13.0 ns, respectively. Meanwhile, the defect densities of the SCs are reduced to 1.02 × 109 and 1.85 × 109 cm−3, respectively. X‐ray detectors based on Br‐doped CBI and Cl‐doped CBI SCs exhibit high X‐ray sensitivity of 23071.3 and 18525.3 μC Gyair−1 cm−2 at an electric field of 40 V mm−1, respectively. In addition, the X‐ray detection limit reaches 1.07 and 1.35 nGyairs−1 at an electric field of 2.5 V mm−1, respectively. [ABSTRACT FROM AUTHOR]

Direct X‐ray detectors require high‐quality and large‐size materials to reduce radiation hazards. As an all‐inorganic lead‐free perovskite, Cs3Bi2I9 has good prospects for research and applications in the field of X‐ray detection. A refined evaporation method is proposed for the growth of Cs3Bi2I9 single crystals (SCs), and a high‐quality SC with a size of 18 × 20.5 × 3 mm3 is obtained. Due to the anisotropy of Cs3Bi2I9 SCs, two different device structures, vertical and coplanar, are designed. The coplanar device has a higher sensitivity of 59 464.4 µC Gyair−1 cm−2, while the vertical device performs better on the limit of detection (LoD), with an LodD as low as 1.27 nGyair s−1. [ABSTRACT FROM AUTHOR]

We study a phase-field model, which describes the transformations for the austenite-martensite and the multiple twinning in Martensite. The model consists of two nonlinear parabolic equations of second order. We first show the existence of local solutions to an initial-boundary value problem by utilizing the Banach fixed-point theorem. Then we verify the solutions is global. Finally we investigate the regularity and uniqueness of the solution. [ABSTRACT FROM AUTHOR]

A supramolecular nanoprodrug (DOX@GP5⊃Pro-NFA) was constructed based on the host–guest complexation of chloride channel blocker prodrug (Pro-NFA) and glycosylated pillar[5]arene (GP5), which could target tumor cells via galactose and release DOX/NFA responsively under esterase stimulation. In vitro studies revealed that this supramolecular nanoprodrug can overcome drug resistance through inhibiting chloride channels as well as inhibiting the migration of HepG2/ADR cells. This strategy can therefore achieve enhanced potency in chemotherapy through reverse chemoresistance. [ABSTRACT FROM AUTHOR]

We introduce a mesoscale model capable of describing transformations between martensitic variants as well as twinning. The model consists of two nonlinear parabolic equations of second order, and one of equations is degenerate. We prove the existence of global‐in‐time solutions to an initial‐boundary value problem in one space dimension of this model. [ABSTRACT FROM AUTHOR]

Loss of estrogen receptor α (ERα) expression and gain of TWIST (TWIST1) expression in breast tumors correlate with increased disease recurrence and metastasis and poor disease-free survival. However, the molecular and functional regulatory relationship between TWIST and ERα are unclear. In this study, we found TWIST was associated with a chromatin region in intron 7 of the human ESR1 gene coding for ERα. This association of TWIST efficiently recruited the nucleosome remodeling and deacetylase (NuRD) repressor complex to this region, which subsequently decreased histone H3K9 acetylation, increased histone H3K9 methylation and repressed ESR1 expression in breast cancer cells. In agreement with these molecular events, TWIST expression was inversely correlated with ERα expression in both breast cancer cell lines and human breast ductal carcinomas. Forced expression of TWIST in TWIST-negative and ERα-positive breast cancer cells such as T47D and MCF-7 cells reduced ERα expression, while knockdown of TWIST in TWIST-positive and ERα-negative breast cancer cells such as MDA-MB-435 and 4T1 cells increased ERα expression. Furthermore, inhibition of histone deacetylase (HDAC) activity including the one in NuRD complex significantly increased ERα expression in MDA-MB-435 and 4T1 cells. HDAC inhibition together with TWIST knockdown did not further increase ERα expression in 4T1 and MDA-MB-435 cells. These results demonstrate that TWIST/NuRD represses ERα expression in breast cancer cells. Therefore, TWIST may serve as a potential molecular target for converting ERα-negative breast cancers to ERα-positive breast cancers, allowing these cancers to restore their sensitivity to endocrine therapy with selective ERα antagonists such as tamoxifen and raloxifene.