Ultrasound-Assisted Hydrothermal Synthesis of Highly Fluorescent Sulfur Quantum Dots for Fe3+ Ion and Ascorbic Acid Detection in Real Samples.

In this work, the ultrasound-assisted hydrothermal synthesis method offers a facile method to synthesize highly efficient photoluminescence sulfur quantum dots (SQDs). Impressively, a switchable fluorescent "on-off-on" sensor was developed using the acquired SQDs, which are capable of sequentially detecting iron ions (Fe3+) and ascorbic acid (AA) with exceptional sensitivity and selectivity. Meanwhile, SQDs and Fe3+ formed complexes through coordination, causing the fluorescence quenching of SQDs because of the static quenching effect. Upon the addition of AA into the SQDs/Fe3+ system, a redox-reaction-mediated mechanism leads to the recovery of fluorescence. The fluorescence intensity of SQDs exhibits a linear relationship with the concentrations of Fe3+ and AA in the ranges 5-30 and 20-100 µM, respectively. Notably, the detection limits achieved are 14.31 nM for Fe3+ and 0.64 µM for AA. Moreover, the chemosensor was successfully employed for monitoring Fe3+ in real water samples and AA in fruits. These results demonstrate the excellent analysis and detection capabilities of SQDs in the complex environment.

Cell-Free DNA Fragmentomics: The Novel Promising Biomarker.

Cell-free DNA molecules are released into the plasma via apoptotic or necrotic events and active release mechanisms, which carry the genetic and epigenetic information of its origin tissues. However, cfDNA is the mixture of various cell fragments, and the efficient enrichment of cfDNA fragments with diagnostic value remains a great challenge for application in the clinical setting. Evidence from recent years shows that cfDNA fragmentomics' characteristics differ in normal and diseased individuals without the need to distinguish the source of the cfDNA fragments, which makes it a promising novel biomarker. Moreover, cfDNA fragmentomics can identify tissue origins by inferring epigenetic information. Thus, further insights into the fragmentomics of plasma cfDNA shed light on the origin and fragmentation mechanisms of cfDNA during physiological and pathological processes in diseases and enhance our ability to take the advantage of plasma cfDNA as a molecular diagnostic tool. In this review, we focus on the cfDNA fragment characteristics and its potential application, such as fragment length, end motifs, jagged ends, preferred end coordinates, as well as nucleosome footprints, open chromatin region, and gene expression inferred by the cfDNA fragmentation pattern across the genome. Furthermore, we summarize the methods for deducing the tissue of origin by cfDNA fragmentomics.

Design and experimental study of a fiber Bragg grating strain sensor with enhanced sensitivity.

A novel high-sensitivity fiber Bragg grating (FBG) strain sensor is reported, to the best of our knowledge. The sensitivity of the sensor is improved by fixing the FBG on an elastic substrate with a sensitization function. The sensitization principle of the designed sensor is introduced, and the mathematical model of the sensor is established. In the static and dynamic experiments of the sensor, the effect of adhesive between the sensor and the measured structure on the sensitivity of the FBG strain sensor is experimentally investigated. The experimental results show that the adhesive with high shear strength is beneficial to the realization of a high-sensitivity sensor. The sensor fixed with planting bar glue can achieve a sensitivity of 9.42 pm/µÎµ, a repeatability error of 4.79%, and a hysteresis error of 3.36%, which is consistent with theoretical and simulation results. The designed high-sensitivity strain sensor has a simple structure, small size, and convenient installation, so it has a good application prospect in micro-strain monitoring.

The risk of ovarian cancer in hormone replacement therapy users: a systematic review and meta-analysis.

Background: With the increasing use of hormone replacement therapy (HRT), there is a need to understand its impact on the occurrence of female malignant tumors. This systematic review and meta-analysis aimed to assess the risk of ovarian cancer associated with HRT and its related risk factors. Methods: PUBMED, OVID, Embase, Cochrane, and Web of Science were searched from 1980 to April 2022 to identify studies on the risk of ovarian cancer and hormone replacement therapy. The random-effects model was used to estimate the pooled risk of HRT in ovarian cancer, both in cohort studies and case-control studies. Additionally, the analysis examined the outcomes associated with different types of estrogen plus progesterone regimens. Meta-regression and sensitive analysis were performed to evaluate the heterogeneity. Results: 21 cohort studies (involving 15,313 cases and 4,564,785 participants) and 30 case-control studies (including 18,738 cases and 57,747 controls) were analyzed. The pooled risks of ovarian cancer for HRT users were 1.20 (95% confidence interval [CI] 1.01-1.44) from cohort studies and 1.13 (95%CI 1.04-1.22) from case-control studies. However, after restricting the study period to recent decades, the significant results indicating a higher risk disappeared in cohort studies conducted after 2010 and in case-control studies conducted after 2006. Furthermore, the continuous use of estrogen-progesterone replacement therapy (EPRT) was associated with a risk comparable to that of sequential use. Subgroup analysis showed that both estrogen replacement treatment (ERT) and EPRT had minor risks; The risk further increased with prolonged exposure time, particularly for durations exceeding 10 years. Additionally, serous ovarian cancer appeared to be more susceptible than other pathological types. Conclusion: The risk of ovarian cancer associated with HRT has been decreasing over time. However, ERT may increase this risk, particularly when used for an extended period. It is recommended that long-time users consider continuous EPRT as a safer alternative. Systematic review registration: www.crd.york.ac.uk/prospero/, identifier CRD42022321279.

Achieving Purely Organic Room-Temperature Phosphorescence Mediated by a Host-Guest Charge Transfer State.

Strategies for developing purely organic materials exhibiting both high efficiency and persistent room-temperature phosphorescence (RTP) have remained ambiguous and challenging. Herein, we propose that introducing an intermediate charge transfer (CT) state into the donor-acceptor binary molecular system holds promise for accomplishing this goal. Guest materials showing gradient ionization potentials were selected to fine-tune the intermolecularly formed CT state when doped into the same host material with a large electron affiliation potential. Such a CT intermediate state accelerates the population of the triplet exciton to benefit phosphorescent emission and decreases the phosphorescence lifetime via quenching the long-lived triplet excitons. As a result, a "trade-off" between a long phosphorescence lifetime (595 ms) and a high phosphorescent quantum yield (27.5%) can be obtained by tuning the host-guest energy gap offset. This finding highlights the key role of CT in RTP emission and provides new guidance for developing novel RTP systems.

Boosting purely organic room-temperature phosphorescence performance through a host-guest strategy.

The host-guest doping system has aroused great attention due to its promising advantage in stimulating bright and persistent room-temperature phosphorescence (RTP). Currently, exploration of the explicit structure-property relationship of bicomponent systems has encountered obstacles. In this work, two sets of heterocyclic isomers showing promising RTP emissions in the solid state were designed and synthesized. By encapsulating these phosphors into a robust phosphorus-containing host, several host-guest cocrystalline systems were further developed, achieving highly efficient RTP performance with a phosphorescence quantum efficiency (ϕ P) of ∼26% and lifetime (τ P) of ∼32 ms. Detailed photophysical characterization and molecular dynamics (MD) simulation were conducted to reveal the structure-property relationships in such bicomponent systems. It was verified that other than restricting the molecular configuration, the host matrix could also dilute the guest to avoid concentration quenching and provide an external heavy atom effect for the population of triplet excitons, thus boosting the RTP performance of the guest.

The Prevalence of Osteoporosis Tested by Quantitative Computed Tomography in Patients With Different Glucose Tolerances.

AIM: The objectives of the present study were to compare bone characteristics with quantitative computed tomography (QCT) and other metabolic factors relevant to bone health in subjects with normal glucose tolerance, impaired glucose tolerance (IGT), and diabetes mellitus (DM) and to evaluate the association of various laboratory factors with bone characteristics qualified by QCT. METHODS: This cross-sectional population-based survey of diabetes and metabolic syndrome was conducted in Pinggu, China. The oral glucose tolerance test was conducted and QCT was tested. The volumetric bone mineral density (vBMD) of lumbar vertebrae 2 through 4 was measured. RESULTS: Among the 4001 eligible participants, the average age was 47.41 ± 11.86 years. The prevalence of osteoporosis evaluated by QCT was 10.6% in the normal glucose tolerance group, 14.8% in the IGT group, and 16.9% in the DM group. Multivariate linear regression analysis showed that age was negatively associated with vBMD, whereas body mass index and waist-hip ratio were positively associated with vBMD across all participants. However, the levels of hemoglobin A1c, fasting plasma glucose, and postprandial glucose were not associated with vBMD after adjusting for sex, age, systolic and diastolic blood pressure, body mass index, total cholesterol, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, FT4, FT3, thyroid-stimulating hormone, urine albumin-to-creatinine ratio, creatinine, and serum uric acid. CONCLUSIONS: We found that the prevalence of osteoporosis evaluated by QCT was 10.6% in the normal glucose tolerance group, 14.8% in the IGT group, and 16.9% in the DM group. The levels of hemoglobin A1c, fasting plasma glucose, and postprandial glucose were not associated with vBMD after adjusting for metabolic factors in a Chinese sample.

Pyridine-Based Bipolar Hosts for Solution-Processed Bluish-Green Thermally Activated Delayed Fluorescence Devices: A Subtle Regulation of Chemical Stability and Carrier Transportation.

Versatile host materials with good chemical stability and carrier-transporting ability are quite responsible for achieving stable solution-processed thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs). Herein, we reported three bipolar dendritic hosts with or without the electron-withdrawing pyridine moiety via 6-site-linkages, namely, 3,3'-bis(3,3″,6,6″-tetra-tert-butyl-9'H-[9,3':6',9″-tercarbazol]-9'-yl)-1,1'-biphenyl (mCDtCBP), 3,3″,6,6″-tetra-tert-butyl-9'-(6-(3-(3,3″,6,6″-tetra-tert-butyl-9'H-[9,3':6',9″-tercarbazol]-9'-yl)phenyl)pyridine-2-yl)-9'H-9,3':6',9″-tercarbazole (mCDtCBPy), and 6,6'-bis(3,3″,6,6″-tetra-tert-butyl-9'H-[9,3':6',9″-tercarbazol]-9'-yl)-2,2'-bipyridine (mCDtCBDPy), exhibiting outstanding solubility, thermal stability as well as electrochemical stability. According to the calculation of bond dissociation energy (BDE), photodegradation results, and carrier dynamics evaluation, a significant relationship between device stability and the pyridine-based dendritic hosts was uncovered. Using mCDtCDPy with the highest electron mobility as the host, the solution-processed bluish-green TADF-OLED showed the shortest operational lifetime due to the unbalanced charge fluxes despite its highest anionic BDE for good chemical stability. However, the device based on mCDtCBPy exhibited twice longer lifetime than that based on mCDtCBP in spite of their similar balanced charge transportation, highlighting the importance of higher anionic BDE of the C-N bond in the device degradation process. Our findings unveiled a potential approach to achieve a subtle regulation of chemical stability and carrier transportation for realizing stable solution-processed TADF-OLEDs.

Achieving high-efficiency purely organic room-temperature phosphorescence materials by boronic ester substitution of phenoxathiine.

The effect of boronic ester substitution on the room-temperature phosphorescence properties of phenoxathiine-based derivatives was thoroughly investigated. A significantly improved phosphorescence quantum efficiency of up to 20% in the crystalline state was achieved by delicate molecular manipulation for both enhanced spin-orbital coupling and compact intermolecular packing.

Achieving Enhanced Thermally Activated Delayed Fluorescence Rates and Shortened Exciton Lifetimes by Constructing Intramolecular Hydrogen Bonding Channels.

A fast radiative rate, highly suppressed nonradiation, and a short exciton lifetime are key elements for achieving efficient thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) with reduced efficiency roll-off at a high current density. Herein, four representative TADF emitters are designed and synthesized based on the combination of benzophenone (BP) or 3-benzoylpyridine (BPy3) acceptors, with dendritic 3,3″,6,6″-tetra-tert-butyl-9'H-9,3':6',9″-tercarbazole (CDTC) or 10H-spiro(acridine-9,9'-thioxanthene) (TXDMAc) donors, respectively. Density functional theory simulation and X-ray diffraction analysis validated the formation of CH···N intramolecular hydrogen bonds regarding the BPy3-CDTC and BPy3-TXDMAc compounds. Notably, the construction of intramolecular hydrogen bonding within TADF emitters significantly enhances the intramolecular charge transfer (ICT) strength while reducing the donor-acceptor (D-A) dihedral angle, resulting in accelerated radiative and suppressed nonradiative processes. With short TADF exciton lifetimes (τTADF) and high photoluminescence quantum yields (ϕPL), OLEDs employing BPy3-CDTC and BPy3-TXDMAc dopants realized maximum external quantum efficiencies (EQEs) up to 18.9 and 25.6%, respectively. Moreover, the nondoped device based on BPy3-TXDMAc exhibited a maximum EQE of 18.7%, accompanied by an extremely small efficiency loss of only 4.1% at the luminance of 1000 cd m-2. In particular, the operational lifetime of the sky-blue BPy3-CDTC-based device was greatly extended by 10 times in contrast to the BP-CDTC-based counterpart, verifying the idea that the in-built intramolecular hydrogen bonding strategy was promising for the realization of efficient and stable TADF-OLEDs.

Fluorene-Based Two-Dimensional Covalent Organic Framework with Thermoelectric Properties through Doping.

Organic semiconductors have great potential as flexible thermoelectric materials. A fluorene-based covalent organic framework (FL-COF-1) was designed with the aim of creating an enhanced π-π interaction among the crystalline backbones. By the introduction of fluorene units into the frameworks, the FL-COF-1 had high thermal stability with a BET surface area over 1300 m2 g-1. The open frameworks were favorable for doping with iodine and followed with the improved charge carrier mobility. The compressed pellet of I2@FL-COF-1 exhibited a high Seebeck coefficient of 2450 µV K-1 and power factor of 0.063 µW m-1 K-2 at room temperature, giving the first example of COFs' potential application as thermoelectric materials.

Immobilization of ionic liquids to covalent organic frameworks for catalyzing the formylation of amines with CO2 and phenylsilane.

We presented the immobilization of ionic liquids on the channel walls of COFs using a post-synthetic strategy. The ionic [Et4NBr]50%-Py-COF afforded a high CO2 adsorption capacity of 164.6 mg g(-1) (1 bar, 273 K) and was developed as an effective heterogeneous catalyst for the transformation of CO2 into value-added formamides under ambient conditions.