Chiral Phosphorescent Carbonized Polymer Dots Relayed Light-Harvesting System for Color-Tunable Circularly Polarized Room Temperature Phosphorescence.

Carbonized polymer dots (CPDs) with a circularly polarized fluorescence property have received increasing attention in recent years. However, it is still a great challenge to construct circularly polarized room-temperature phosphorescence (CPRTP) CPDs. Herein, a simple approach to the synthesis of intrinsically CPRTP CPDs for the first time by utilizing sodium alginate and l-/d-arginine as precursors under relatively mild reaction conditions is presented. Notably, the CPDs exhibit both chirality and green RTP in solid states. Furthermore, color-tunable CPRTP is successfully achieved by engineering chiral light-harvesting systems based on circularly polarized phosphorescence resonance energy transfer (C-PRET) where the CPDs with green RTP function as an initiator of chirality and light absorbance, and commercially available fluorescent dyes with different emission colors ranging from yellow to red serve as the terminal acceptors. Through one-step or sequential C-PRET, the light-harvesting systems can simultaneously furnish energy transfer and chirality transmission/amplification. Given the multicolor long afterglow, lifetime-tunable, and CPRTP properties, their potential applications in multiple information encryption are demonstrated.

Cell-cell communication inference and analysis in the tumour microenvironments from single-cell transcriptomics: data resources and computational strategies.

Carcinomas are complex ecosystems composed of cancer, stromal and immune cells. Communication between these cells and their microenvironments induces cancer progression and causes therapy resistance. In order to improve the treatment of cancers, it is essential to quantify crosstalk between and within various cell types in a tumour microenvironment. Focusing on the coordinated expression patterns of ligands and cognate receptors, cell-cell communication can be inferred through ligand-receptor interactions (LRIs). In this manuscript, we carry out the following work: (i) introduce pipeline for ligand-receptor-mediated intercellular communication estimation from single-cell transcriptomics and list a few available LRI-related databases and visualization tools; (ii) demonstrate seven classical intercellular communication scoring strategies, highlight four types of representative intercellular communication inference methods, including network-based approaches, machine learning-based approaches, spatial information-based approaches and other approaches; (iii) summarize the evaluation and validation avenues for intercellular communication inference and analyze the advantages and limitations for the above four types of cell-cell communication methods; (iv) comment several major challenges while provide further research directions for intercellular communication analysis in the tumour microenvironments. We anticipate that this work helps to better understand intercellular crosstalk and to further develop powerful cell-cell communication estimation tools for tumor-targeted therapy.

Room Temperature Phosphorescence Carbon Dots: Preparations, Regulations, and Applications.

Room temperature phosphorescence (RTP) materials have drawn considerable attention by virtue of their outstanding features. Compared with organometallic complexes and pure organic compounds, carbon dots (CDs) have emerged as a new type of RTP materials, which show great advantages, such as moderate reaction condition, low toxicity, low cost, and tunable optical properties. In this review, the important progress made in RTP CDs is summarized, with an emphasis on the latest developments. The synthetic strategies of RTP CDs will be comprehensively summarized, followed by detailed introduction of their performance regulation and potential applications in anti-counterfeiting, information encryption, sensing, light-emitting diodes, and biomedicine. Finally, the remaining major challenges for RTP CDs are discussed and new opportunities in the future are proposed.

Rational Design of the First Ammonium Magnesium Borate with Deep-Ultraviolet Cutoff Edge and Moderate Birefringence and Further Investigation into the Nature of Ammonium in the Borate System.

Through the rational design of the experimental method, the first combination of ammonium and magnesium in the borate system was successfully achieved. In this paper, a case of ammonium magnesium borate, (NH4)2{Mg(H2O)2[B6O7(OH)6]2}·2H2O, was successfully synthesized by a mild hydrothermal method at a relatively low temperature. A brief review was performed to show the participation of NH4+ in the recent development of optical materials. By discussing the optimum synthesis method of ammonium-containing borates and the main factors affecting the dimensionality of B-O anionic groups in their structures, the design strategy for synthesizing ammonium-containing borate and adjusting its structure has been put forward. Relevant experimental measurement results and the first-principles calculation results show that the title compound has a deep-UV cutoff edge (<200 nm) and moderate birefringence (Δncal. = 0.064 @546 nm), which indicates its potential application in the deep-UV region.

The investigation of reduced field-of-view diffusion-weighted imaging (DWI) in patients with nasopharyngeal carcinoma: comparison with conventional DWI.

BACKGROUND: Field-of-view optimized and constrained undistorted single-shot imaging (FOCUS) is a new sequence that shows enhanced anatomical details, improving the diffusion-weighted (DW) images. PURPOSE: To investigate the value of FOCUS diffusion-weighted imaging (DWI) in the evaluation of nasopharyngeal carcinoma (NPC) and compare it with the single-shot echo planner imaging (SS-EPI) DWI approach. MATERIAL AND METHODS: A total of 87 patients with NPC underwent magnetic resonance imaging, including FOCUS and SS-EPI DWI sequences. The signal-to-noise ratio (SNR), signal-intensity ratio (SIR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC) values of the nasopharyngeal lesions were measured and compared. According to the clinical stages of patients, T and N were divided into early and advanced stage groups, respectively. The mean ADC values of the two techniques were computed, and the area under the curve (AUC) was estimated to calculate the diagnostic efficiency. RESULTS: Subjective and objective image qualitative values of FOCUS were significantly higher than those of SS-EPI. The ADC values for FOCUS of early T and N stages were significantly lower than those of the advanced stages. CONCLUSION: FOCUS provides significantly better image quality in NPC compared to SS-EPI, with lower ADC values for early-stage disease than late-stage disease.

Plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy induced by type 2 diabetes mellitus.

The glymphatic system is a recently discovered glial-dependent macroscopic interstitial waste clearance system that promotes the efficient elimination of soluble proteins and metabolites from the central nervous system. Its anatomic foundation is the astrocytes and aquaporin-4 (AQP4) water channels on the endfeet of astrocytes. The aim of this study is to evaluate the plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy (PDN) induced by type 2 diabetes mellitus. PDN rats were modeled under a high-fat and high-glucose diet with a low dose of streptozotocin. MRI was applied to observe the infiltration and clearance of contrast to indicate the functional variability of the glymphatic system at the spinal cord level. The paw withdrawal threshold was used to represent mechanical allodynia. The numerical change of glial fibrillary acidic protein (GFAP) positive astrocytes was assessed and the polarity reversal of AQP4 protein was measured by immunofluorescence. As a result, deceased contrast infiltration and clearance, enhanced mechanical allodynia, increased number of GFAP positive astrocytes, and reversed polarity of AQP4 protein were found in the PDN rats. The above molecular level changes may contribute to the impairment of the spinal glymphatic system in PDN rats. This study revealed the molecular and functional variations of the spinal glymphatic system in PDN rats and for the first time indicated that there might be a correlation between the impaired spinal glymphatic system and PDN rats.

Real-time X-ray imaging of mouse cerebral microvessels in vivo using a pixel temporal averaging method.

Rodents are used extensively as animal models for the preclinical investigation of microvascular-related diseases. However, motion artifacts in currently available imaging methods preclude real-time observation of microvessels in vivo. In this paper, a pixel temporal averaging (PTA) method that enables real-time imaging of microvessels in the mouse brain in vivo is described. Experiments using live mice demonstrated that PTA efficiently eliminated motion artifacts and random noise, resulting in significant improvements in contrast-to-noise ratio. The time needed for image reconstruction using PTA with a normal computer was 250 ms, highlighting the capability of the PTA method for real-time angiography. In addition, experiments with less than one-quarter of photon flux in conventional angiography verified that motion artifacts and random noise were suppressed and microvessels were successfully identified using PTA, whereas conventional temporal subtraction and averaging methods were ineffective. Experiments performed with an X-ray tube verified that the PTA method could also be successfully applied to microvessel imaging of the mouse brain using a laboratory X-ray source. In conclusion, the proposed PTA method may facilitate the real-time investigation of cerebral microvascular-related diseases using small animal models.

Effects of dynamic individualized PEEP guided by driving pressure in laparoscopic surgery on postoperative atelectasis in elderly patients: a prospective randomized controlled trial.

BACKGROUND: Driving pressure (ΔP = Plateau pressure-PEEP) is highly correlated with postoperative pulmonary complications (PPCs) and appears to be a promising indicator for optimizing ventilator settings. We hypothesized that dynamic, individualized positive end-expiratory pressure (PEEP) guided by ΔP could reduce postoperative atelectasis and improve intraoperative oxygenation, respiratory mechanics, and reduce the incidence of PPCs on elderly patients undergoing laparoscopic surgery. METHODS: Fifty-one elderly patients who were subject to laparoscopic surgery participated in this randomized trial. In the PEEP titration group (DV group), the PEEP titration was decremented to the lowest ΔP and repeated every 1 h. Additional procedures were also performed when performing predefined events that may be associated with lung collapse. In the constant PEEP group (PV group), a PEEP of 6 cmH2O was used throughout the surgery. Moreover, zero PEEP was applied during the entire procedure in the conventional ventilation group (CV group). The primary objective of this study was lung ultrasound score noted at the end of surgery and 15 min after admission to the post-anesthesia care unit (PACU) at 12 lung areas bilaterally. The secondary endpoints were perioperative oxygenation function, expiratory mechanics, and the incidence of the PPCs. RESULTS: The lung ultrasound scores of the DV group were significantly lower than those in the PV group and CV group (P < 0.05), whereas there was no significant difference between the PV group and CV group (P > 0.05). The lung static compliance (Cstat) and ΔP at all the intraoperative time points in the DV group were significantly better compared to the PV group and the CV group (p < 0.05). CONCLUSIONS: Intraoperative titrated PEEP reduced postoperative lung atelectasis and improved respiratory mechanics in elderly patients undergoing laparoscopic surgery. Meanwhile, standard PEEP strategy is not superior to conventional ventilation in reducing postoperative pulmonary atelectasis in laparoscopic surgery.

Pelvic Injury Discriminative Model Based on Data Mining Algorithm.

OBJECTIVES: To reduce the dimension of characteristic information extracted from pelvic CT images by using principal component analysis (PCA) and partial least squares (PLS) methods. To establish a support vector machine (SVM) classification and identification model to identify if there is pelvic injury by the reduced dimension data and evaluate the feasibility of its application. METHODS: Eighty percent of 146 normal and injured pelvic CT images were randomly selected as training set for model fitting, and the remaining 20% was used as testing set to verify the accuracy of the test, respectively. Through CT image input, preprocessing, feature extraction, feature information dimension reduction, feature selection, parameter selection, model establishment and model comparison, a discriminative model of pelvic injury was established. RESULTS: The PLS dimension reduction method was better than the PCA method and the SVM model was better than the naive Bayesian classifier (NBC) model. The accuracy of the modeling set, leave-one-out cross validation and testing set of the SVM classification model based on 12 PLS factors was 100%, 100% and 93.33%, respectively. CONCLUSIONS: In the evaluation of pelvic injury, the pelvic injury data mining model based on CT images reaches high accuracy, which lays a foundation for automatic and rapid identification of pelvic injuries.

Endobronchial Ultrasound Improves Evaluation of Recurrent Laryngeal Nerve Lymph Nodes in Esophageal Squamous Cell Carcinoma Patients.

BACKGROUND: The bilateral recurrent laryngeal nerve (RLN) lymph nodes are the most common metastatic site for esophageal squamous cell carcinoma (ESCC); however, the RLNs are susceptible to injury during dissection. Clinically, there is an urgent need to determine an effective diagnostic method for RLN nodes to help achieve selective nodal dissection and avoid potential serious complications by performing more conservative surgery for those with nonmetastatic nodes. Here, we innovatively applied endobronchial ultrasonography (EBUS) and investigated its diagnostic performance for preoperative evaluation of RLN nodes in ESCC patients. PATIENTS AND METHODS: All 81 enrolled ESCC patients underwent preoperative EBUS and CT examinations. The ability of EBUS and CT to detect RLN node metastasis was evaluated based on the resulting sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV). RESULTS: The diagnostic performance of EBUS was superior to that of CT; in particular, EBUS of the left RLN (L-RLN) nodes presented the best sensitivity, specificity, PPV, NPV, and accuracy compared with EBUS evaluations of the right RLN (R-RLN) nodes, CT of the L-RLN and R-RLN nodes. Moreover, EBUS combined with CT increased the NPV relative to that of EBUS or CT alone, promoting the ability to identify true-negative RLN nodes. In particular, the NPVs of the combined modality were 100% for both the L- and R-RLN nodes in early-T-stage (T1-T2) ESCC. CONCLUSIONS: EBUS is an efficient tool for RLN node evaluation, and the combination with CT may provide better guidance for selective RLN node dissection in ESCC patients.

First Report of Diaporthe hongkongensis Causing Fruit rot on Peach (Prunus persica) in China.

Peach [Prunus persica (L.) Batsch] is an important deciduous fruit tree in the family Rosaceae and is a widely grown fruit in China (Verde et al., 2013). In July and August 2018, a fruit rot disease was observed in a few peach orchards in Zhuzhou city, the Hunan Province of China. Approximately 30% of the fruit in more than 400 trees was affected. Symptoms displayed were brown necrotic spots that expanded, coalesced, and lead to fruit being rotten. Symptomatic tissues excised from the margins of lesions were surface sterilized in 70% ethanol for 10 s, 0.1% HgCl2 for 2 min, rinsed with sterile distilled water three times, and incubated on potato dextrose agar (PDA) at 26°C in the dark. Fungal colonies with similar morphology developed, and eight fungal colonies were isolated for further identification. Colonies grown on PDA were grayish-white with white aerial mycelium. After an incubation period of approximately 3 weeks, pycnidia developed and produced α-conidia and ß-conidia. The α-conidia were one-celled, hyaline, fusiform, and ranged in size from 6.0 to 8.4 × 2.1 to 3.1 µm, whereas the ß-conidia were filiform, hamate, and 15.0 to 27.0 × 0.8 to 1.6 µm. For molecular identification, total genomic DNA was extracted from the mycelium of a representative isolate HT-1 and the internal transcribed spacer region (ITS), ß-tubulin gene (TUB), translation elongation factor 1-α gene (TEF1), calmodulin (CAL), and histone H3 gene (HIS) were amplified and sequenced (Meng et al. 2018). The ITS, TUB, TEF1, CAL and HIS sequences (GenBank accession nos. MT740484, MT749776, MT749778, MT749777, and MT749779, respectively) were obtained and in analysis by BLAST against sequences in NCBI GenBank, showed 99.37 to 100% identity with D. hongkongensis or D. lithocarpus (the synonym of D. hongkongensis) (Gao et al., 2016) (GenBank accession nos. MG832540.1 for ITS, LT601561.1 for TUB, KJ490551.1 for HIS, KY433566.1 for TEF1, and MK442962.1 for CAL). Pathogenicity tests were performed on peach fruits by inoculation of mycelial plugs and conidial suspensions. In one set, 0.5 mm diameter mycelial discs, which were obtained from an actively growing representative isolate of the fungus on PDA, were placed individually on the surface of each fruit. Sterile agar plugs were used as controls. In another set, each of the fruits was inoculated by application of 1 ml conidial suspension (105 conidia/ml) by a spray bottle. Control assays were carried out with sterile distilled water. All treatments were maintained in humid chambers at 26°C with a 12-h photoperiod. The inoculation tests were conducted twice, with each one having three fruits as replications. Six days post-inoculation, symptoms of fruit rot were observed on inoculated fruits, whereas no symptoms developed on fruits treated with agar plugs and sterile water. The fungus was re-isolated and identified to be D. hongkongensis by morphological and molecular methods, thus fulfilling Koch's Postulates. This fungus has been reported to cause fruit rot on kiwifruit (Li et al. 2016) and is also known to cause peach tree dieback in China (Dissanayake et al. 2017). However, to our knowledge, this is the first report of D. hongkongensis causing peach fruit rot disease in China. The identification of the pathogen will provide important information for growers to manage this disease.

Identification and functional analysis of spermatogenesis-associated gene modules in azoospermia by weighted gene coexpression network analysis.

Nonobstructive azoospermia (NOA) or testicular failure is the most severe form of male infertility. A variety of conditions, both acquired and congenital, can cause azoospermia. However, in a large number of azoospermia patients who are classified as idiopathic cases, the etiology remains poorly understand mainly due to the lack of knowledge of all the genetic causes and molecular mechanisms responsible for spermatogenesis failure. Identification of the key gene modules and pathways-related spermatogenesis failure might help to reveal the mechanisms of idiopathic azoospermia. Therefore, the expression patterns of spermatogenesis-associated genes in NOA were analyzed by weighted gene coexpression network analysis (WGCNA) based on two public microarray data sets (GSE45885 and GSE45887), which included 51 samples and 32,321 genes. We identified a module (turquoise) that was significantly related to the Johnsen score of the testicular samples. In addition, the results of function and pathway enrichment analyses based on the online bioinformatics database Metascape revealed that genes in the turquoise module were mainly related to the process of spermatogenesis and spermatid development. To further identify spermatogenesis-associated genes, a microarray data set (GSE926) of murine testis at different developmental time points was analyzed by WGCNA. The blue module in GSE926 was significantly related to the time of murine testis development. The overlap study and k-core analysis based on protein-protein interaction network revealed that spermatogenesis- and spermatid development-associated genes, including glyceraldehyde-3-phosphate dehydrogenase, ADAM metallopeptidase domain 2, transition protein 1, testis-specific serine kinase 2, transition protein 2, and germ cell-associated 1 (GSG1), were further identified in the selected modules. The expression profile of GSG1 in human testis was chosen for further study using immunochemistry staining. Taken together, these screened gene modules and pathways provided a more detailed genetic and molecular mechanism underlying spermatogenesis failure occurrence and holds promise as potential diagnosis biomarkers and therapeutic targets.

Sudden death from an epileptic seizure due to capillary telangiectasias in the hippocampus.

Cerebral capillary telangiectasia (CCT) is a type of vascular malformation that is incidentally encountered in clinical practice. Diseased vessels are small and usually clinically benign over the course of a patient's life. Although most CCT patients are asymptomatic, the situation becomes complicated when trauma is encountered. A case of sudden death due to an epileptic episode after very mild head trauma is reported, including a retrospective study of 12 cases, to remind peers to pay close attention to CCT especially when located in important functional regions of the brain. After immunohistochemical staining and pathological examination, we speculated that the epileptogenic mechanism of CCT may be similar to that of hippocampal sclerosis. As the definite epileptogenic mechanism of CCT in the hippocampus is still elusive, we suggest that more research should be conducted on CCT.

Dental pulp stem cells promote regeneration of damaged neuron cells on the cellular model of Alzheimer's disease.

Alzheimer's disease (AD) is an incurable neurodegenerative disease and many types of stem cells have been used in AD therapy with some favorable effects. In this study, we investigated the potential therapeutical effects of human dental pulp stem cells (hDPSCs) on AD cellular model which established by okadaic acid (OA)-induced damage to human neuroblastoma cell line, SH-SY5Y, in vitro for 24 h. After confirmed the AD cellular model, the cells were co-culture with hDPSCs by transwell co-culture system till 24 h for treatment. Then the cytomorphology of the hDPSCs-treated cells were found to restore gradually with re-elongation of retracted dendrites. Meanwhile, Cell Counting Kit-8 assay and Hoechst 33258 staining showed that hDPSCs caused significant increase in the viability and decrease in apoptosis of the model cells, respectively. Observation of DiI labeling also exhibited the prolongation dendrites in hDPSCs-treated cells which were obviously different from the retraction dendrites in AD model cells. Furthermore, specific staining of α-tubulin and F-actin demonstrated that the hDPSCs-treated cells had the morphology of restored neurons, with elongated dendrites, densely arranged microfilaments, and thickened microtubular fibrils. In addition, results from western blotting revealed that phosphorylation at Ser 396 of Tau protein was significantly suppressed by adding of hDPSCs. These results indicate that hDPSCs may promote regeneration of damaged neuron cells in vitro model of AD and may serve as a useful cell source for treatment of AD.

Metformin Inhibits NLRP3 Inflammasome Expression and Regulates Inflammatory Microenvironment to Delay the Progression of Colorectal Cancer.

BACKGROUND: Colorectal cancer is a common malignant tumor, with about one million people diagnosed with it worldwide each year. Recent studies have found that metformin can inhibit the production of inflammatory factors and regulate the polarization of immune cells. However, whether metformin can regulate the inflammatory microenvironment and delay the progression of colorectal cancer by inhibiting the inflammatory response has not been deeply studied yet. OBJECTIVE: This study aimed to explore the molecular mechanism by which metformin inhibits the expression of NLRP3 inflammasome, regulates the inflammatory microenvironment, and delays the progression of colorectal cancer through in vitro cell experiments. METHODS: In this research, NLRP3 was knocked down in human colorectal cancer cells, and metformin was added to them. Cell proliferation ability was detected by CCK8, and cell migration and invasion abilities were assessed by Transwell assay. The apoptosis rate was determined by flow cytometry. In addition, the expression of NLRP3 inflammatory vesicles and inflammatory factors in each group of cells was studied by qRT-PCR and Western blotting. Finally, clinical colorectal cancer samples were analyzed by immunohistochemistry. RESULTS: The results of the study showed that NLRP3 expression was significantly increased in colorectal cancer cell lines and human colorectal cancer tissues. Knockdown of NLRP3 significantly inhibited tumor cell proliferation, migration, and invasion. In addition, the proliferation, migration and invasion of tumor cells were also significantly reduced by the addition of metformin intervention. Furthermore, qRT-PCR and WB results demonstrated that the expression of IL-1ß, IL-6, TNF- α, TGF-ß, and IL-10 was down-regulated in LS1034 tumor cells after NLRP3 knockdown. In addition, metformin intervention also resulted in different degrees of downregulation of NLRP3 and inflammatory factor expression (p <0.05). Notably, the reduction in inflammatory factors was more pronounced after the combination of NLRP3 knockdown and metformin intervention. CONCLUSION: Metformin can inhibit the expression of NLRP3 inflammasome, thereby suppressing the expression of inflammation-related factors, reducing the damage of the inflammatory microenvironment to normal cells, and delaying the progression of colorectal cancer.

Identification of prognostic m6A modification patterns and score system in melanoma patients.

N6-methyladenosine (m6A) is the most common modification on RNAs and LncRNAs. It plays an important role in cancer stem cell differentiation, T cell differentiation, and immune homeostasis. In this study, we explored the potential roles of m6A modification of RNA in melanoma and investigated the immune cell infiltration in tumor microenvironment in diverse m6Aclusters and different m6Ascore groups. A consensus clustering algorithm determined m6A modification patterns based on 14 m6A regulators, and further explored the biological functions and the connection with TME. An m6A-related gene signature (m6Ascore) was constructed based on m6A-related genes using principal component analysis. Three m6A modification patterns were identified based on 14 m6A regulators, named as m6Aclusters A-C. The prognosis of m6Acluster A was more favorable than m6Aclusters B and C, and it was more closely associated with immune regulation. To quantify the m6A modification patterns of individual tumor, an m6Ascore was constructed, and patients were classified into high and low m6Ascore groups. The low m6Ascore group, which had a favorable prognosis, was more relevant to immunology. The expression of PD-L1 was higher and the immunophenoscore (IPS) revealed stronger response to immunotherapy in the low m6Ascore group. This study identified 3 m6A modification patterns with different immune characteristics and constructed an m6Ascore system to predict prognosis and immunogenicity of patients, which is conducive to clinical prognosis judgment and individual treatment.

Measurement of mass force field driving water refilling of cuttage.

Cuttage is a common plant cultivation method, and the key to its survival is the restoration of water refilling, which remains unclear up to now. We report 3D dynamic imaging of water refilling of cuttage without resorting to any contrast agent. Hydrodynamics of the refilled water flow over time reveals the existence of a unit mass force field with a gradient along the refilling direction, which means that cutting plants also have a gradient force field to drive the recovery of water refilling, as predicted by Cohesion-Tension theory in normal plants. We found that force fields of different functional regions are isolated and independently distributed, which is conducive to ensure the safety of water transmission. At the same time, we also found that there is a so-called "inchworm effect" in the mass force field, which contributes to the force transfer inside the cutting through local force accumulation. Results of this paper demonstrate that the developed method for the measurement of mass force field in-vivo is applicable to help decipher the mechanism of plant water refilling.

Achieving long-lived white circularly polarized luminescence from carbonized polymer dots via phosphorescence resonance energy transfer.

Achieving white-light emission, especially long-lived white circularly polarized luminescence, is challenging. Herein, chiral phosphorescent carbonized polymer dots (CPDs) have been prepared by using chiral polymer sodium alginate and chiral small molecule L-lysine as precursors. Benefiting from the efficient triplet-to-singlet phosphorescence resonance energy transfer (PRET), CPD-based long-lived warm white CPL has been achieved for the first time. This study provides a universal strategy for the convenient and efficient preparation of CPD-based long-lived white CPL materials.

Chiral Aggregation-Induced Emission Carbon Dot-Based Multicolor and Near-Infrared Circularly Polarized Delayed Fluorescence via a Light-Harvesting System.

Circularly polarized luminescence (CPL) materials are the research frontier of chiral luminescence. As a kind of luminescent carbon material, carbon dots (CDs) are expected to become excellent candidates for the construction of CPL materials. However, the construction of CD-based circularly polarized afterglow emission, especially multicolor and near-infrared emission, remains a great challenge due to aggregation-caused quenching and the instability of triplet excitons. In this work, we synthesized chiral CDs with aggregation-induced emission using dithiosalicylic acid and l/d-arginine as precursors through a one-step solvothermal method. Notably, the CDs exhibit green delayed fluorescence (DF) in poly(vinyl alcohol) films. Furthermore, multicolor and near-infrared circularly polarized delayed fluorescence is successfully realized via engineering a chiral light-harvesting system in which the CDs with green DF emission act as energy donors and fluorescent dyes with emission colors ranging from yellow to the near infrared serve as energy acceptors.

Dynamic X-ray speckle-tracking imaging with high-accuracy phase retrieval based on deep learning.

Speckle-tracking X-ray imaging is an attractive candidate for dynamic X-ray imaging owing to its flexible setup and simultaneous yields of phase, transmission and scattering images. However, traditional speckle-tracking imaging methods suffer from phase distortion at locations with abrupt changes in density, which is always the case for real samples, limiting the applications of the speckle-tracking X-ray imaging method. In this paper, we report a deep-learning based method which can achieve dynamic X-ray speckle-tracking imaging with high-accuracy phase retrieval. The calibration results of a phantom show that the profile of the retrieved phase is highly consistent with the theoretical one. Experiments of polyurethane foaming demonstrated that the proposed method revealed the evolution of the complicated microstructure of the bubbles accurately. The proposed method is a promising solution for dynamic X-ray imaging with high-accuracy phase retrieval, and has extensive applications in metrology and quantitative analysis of dynamics in material science, physics, chemistry and biomedicine.