Construction of Carbon Dots with Color-Tunable Aggregation-Induced Emission by Nitrogen-Induced Intramolecular Charge Transfer

As one of the most promising fluorescent nanomaterials, the fluorescence of carbon dots (CDs) in solution is extensively studied. Nevertheless, the synthesis of multicolor solid-state fluorescence (SSF) CDs is rarely reported. Herein, CDs with multicolor aggregation-induced emission are prepared using amine molecules, all of them exhibiting dual fluorescence emission at 480 nm (Em-1) and 580-620 nm (Em-2), which is related to the SS bonds of dithiosalicylic acid and the conjugated structure attached to CO/CN bonds, respectively. As a strong electron-withdrawing group, the increase of CN content makes dual-fluorescent groups on the surface of CDs produce push and pull electrons, which determines intramolecular charge transfer (ICT) between the double emission. With the increase in CN content from 35.6% to 58.4%, the ICT efficiency increases from 8.71% to 45.94%, changing the fluorescence of CDs from green to red. The increase of ICT efficiency causes fluorescence quantum yield enhancement by nearly five times and redshift of the fluorescence peak. Finally, based on the multicolor luminescence properties induced by the aggregation of CDs, pattern encryption and white-LED devices are realized. Based on the fat solubility and strong ultraviolet absorption characteristics of CDs, fingerprint detection and leaf anti-UV hazards are applied.

Salvia miltiorrhiza Derived Carbon Dots and Their Heat Stress Tolerance of Italian Lettuce by Promoting Growth and Enhancing Antioxidant Enzyme Activity

With global warming, plants often suffer damage from high temperatures during the growth process, which inhibits their growth. In this work, carbon dots (CDs), synthesized by Salvia miltiorrhiza (S. miltiorrhiza) with a one-step hydrothermal method, were selected as heat-resistant enhancement agents for plants. Inspired by this background, this work studied Italian lettuce grown at 25, 35, and 45 °C and treated with CD and deionized water control (sprayed on leaves). The results showed that the biomass, chlorophyll content, net photosynthetic rate, activities of SOD (superoxide dismutase), POD (peroxidase), CAT (catalase), soluble sugar, and soluble protein contents of lettuce treated by CDs were increased while the contents of malondialdehyde (MDA) and proline (Pro) were decreased at 35 and 45 °C. The application of CDs at 35 and 45 °C could maintain the growth of plants by reducing oxidative damage and lipid peroxidation especially at the temperature of 35 °C, the growth status of lettuce treated by CDs was no different from that of lettuce grown naturally at the optimal temperature of 25 °C, or even better than the latter. This finding verified that the CDs could significantly improve the high-temperature tolerance of lettuce, thus alleviating the heat stress of plants.

Predicting haemodynamic significance of coronary stenosis with radiomics-based pericoronary adipose tissue characteristics

AIM

To investigate the diagnostic performance of the radiomics features of pericoronary adipose tissue (PCAT) in determining haemodynamically significant coronary artery stenosis as evaluated by fractional flow reserve (FFR).

MATERIALS AND METHODS

A total of 92 patients with clinically suspected coronary artery disease who underwent coronary computed tomography (CT) angiography (CCTA), invasive coronary angiography (ICA), and FFR examination within 1 month were included retrospectively, and 121 lesions were randomly assigned to the training and testing set. Based on manual segmentation of PCAT, 1,116 radiomics features were computed. After radiomics robustness assessment and feature selection, radiomics models were established using the different machine-learning algorithms. The area under the receiver operating characteristic (ROC) curve (AUC) and net reclassification index (NRI) were analysed to compare the discrimination and reclassification abilities of radiomics models.

RESULTS

Two radiomics features were selected after exclusions, and both were significantly higher in coronary arteries with FFR ≤0.8 than those with FFR >0.8. ROC analysis showed that the combination of CCTA and decision tree radiomics model achieved significantly higher diagnostic performance (AUC: 0.812) than CCTA alone (AUC: 0.599, p=0.015). Furthermore, the NRI of the combined model was 0.820 and 0.775 in the training and testing sets, respectively, suggesting the radiomics features of PCAT had were effective in classifying the haemodynamic significance of coronary stenosis.

CONCLUSIONS

Adding PCAT radiomics features to CCTA enabled identification of haemodynamically significant coronary artery stenosis.

Clinical progress and advanced research of red blood cells based drug delivery system

Red blood cells (RBCs) are biocompatible carriers that can be employed to deliver different bioactive substances. In the past few decades, many strategies have been developed to encapsulate or attach drugs to RBCs. Osmotic-based encapsulation methods have been industrialized recently, and some encapsulated RBC formulations have reached the clinical stage for treating tumors and neurological diseases. Inspired by the intrinsic properties of intact RBCs, some advanced delivery strategies have also been proposed. These delivery systems combine RBCs with other novel systems to further exploit and expand the application of RBCs. This review summarizes the clinical progress of drugs encapsulated into intact RBCs, focusing on the loading and clinical trials. It also introduces the latest advanced research based on developing prospects and limitations of intact RBCs drug delivery system (DDS), hoping to provide a reference for related research fields and further application potential of intact RBCs based drug delivery system.

Nitrogen and Sulfur Co-doped Carbon Dots Enhance Drought Resistance in Tomato and Mung Beans

Drought stress is widespread worldwide, which severely restricts world food production. The antioxidant property of carbon dots (CDs) is promising for inflammation and disease treatment. However, little is known about the functions of CDs in the abiotic stress of plants, especially in drought-resistant fields. In this study, CDs were synthesized using cysteine and glucose by the hydrothermal method. The in vitro antioxidant capacity of CDs and the reactive oxygen species (ROS) scavenging capacity were evaluated. We speculate on the antioxidant mechanism of CDs by comparing size distribution, fluorescence spectra, elements, and surface functional groups of CDs before and after oxidation. Besides, we evaluated the effects of CDs on seed germination and seedling physiology under drought stress. Also, the responses of antioxidant CDs to long-term drought stress and subsequent recovery metabolism in tomato plants were evaluated. The results show that CDs accelerated the germination rate and the germination drought resistance index by promoting the water absorption of seeds. CDs enhanced the drought resistance of seedlings by improving the activity of peroxidase (POD) and superoxide dismutase (SOD). Moreover, CDs can activate the antioxidant metabolism activity and upregulate the expression of aquaporin (AQP) genes SlPIP2;7, SlPIP2;12, and SlPIP1;7. All of these results render tomato plants distinguished resilience once rewatering after drought stress. These results facilitate us to design and fabricate CDs to meet the challenge of abiotic stress in food production.

A mild method to prepare nitrogen-rich interlaced porous carbon nanosheets for high-performance supercapacitors

In this work, a non-toxic and mild strategy was presented to efficiently fabricate porous and nitrogen-doped carbon nanosheets. Silkworm cocoon (SCs) acted as carbon source and original nitrogen source. Sodium carbonate (Na₂CO₃) could facilitate the SCs to expose silk protein and played a catalytic role in the subsequent activation of calcium chloride (CaCl₂). Calcium chloride served as pore-making agent. The as-obtained carbon materials with protuberant porous nanosheets exhibit high specific surface area of 731 m² g^-1, rich native nitrogen-doped of 7.91 atomic %, wide pore size distribution from 0.5 to 65 nm, and thus possessing high areal specific capacitances of 34 μF cm^-2 as well as excellent retention rate of 97% after 20 000 cycles at a current density of 20 A g^-1 in 6 M KOH electrolyte. The assembled carbon nanosheet-based supercapacitor displays a maximum energy density of 21.06 Wh kg^-1 at the power density of 225 W kg^-1 in 1 M Na₂SO₄ electrolyte. Experimental results show that a mild and non-toxic treatment of biomass can be an effective and extensible method for preparing optimal porous carbon for electrochemical energy storage.

[Analysis on prediction power of HIV infection risk assessment tool in men who have sex with men in Guizhou province]

Objective: To evaluate the prediction power of HIV infection risk assessment tool and the applicability in MSM in Guizhou province. Methods: MSM were recruited through snowball sampling method. Questionnaire surveys were conducted among the MSM using HIV infection risk assessment tool, and combined with HIV serologic test results, the risk prediction power of HIV infection risk assessment tool was evaluated. Results: A total of 3 379 MSM were recruited from January 2018 to December 2019 in Guizhou. The HIV infection rate was 3.3%(111/3 379). The mean risk scores of HIV positive and HIV negative MSM were (12.15±3.08) and (12.07±3.07), respectively. The difference in risk score was significant between MSM with different HIV status (t=8.69, P<0.001). According to the principle of decision tree, individual risk scores were divided into following three categories: ≤11.96, 11.97-14.80 and >14.80, the HIV infection rate was 0.8%, 4.3% and 8.6% respectively, suggesting that the higher the individual risk score was, the higher the HIV infection rate was (trend χ²=88.18, P<0.001). Multivariate logistic regression analysis showed that the higher the individual risk score was, the higher the risk of HIV infection was. Compared to the total score ≤11.96, the aOR values at total scores of 11.97-14.80 and >14.80 were 6.34 (95%CI: 3.38-11.88) and 14.07(95%CI: 7.44-26.61), respectively. The risk of HIV infection in Miao ethnic group was higher than that in Han ethnic group (aOR=1.83, 95%CI:1.04-3.21), and the risk of HIV infection in those with education level of primary school and below was higher than that in undergraduates or those with education level of junior college and above (aOR=2.50, 95%CI:1.06-5.88), and the risk of HIV infection was higher in those who had bisexual behaviors than in those who had homosexual behaviors (aOR=1.95, 95%CI:1.19-3.19). The risk of HIV infection was higher in those who had never received HIV testing (aOR=1.53, 95%CI:1.01-2.33). The area under the receiver operating characteristic (ROC) curve and area under ROC (AUC) for HIV infection prediction was 0.751 (95%CI:0.710-0.792, P<0.001). The maximum Youden's index was individual risk score of 12.56, and the sensitivity of the risk assessment tool was 0.838, and its specificity was 0.412. Conclusions: The results of HIV infection risk assessment tool in Guizhou indicated that in MSM the higher the individual risk score, the higher the risk of HIV infection is. The tool can be used to evaluate the risk of HIV infection in MSM, but the specificity should be improved.

Boosting zinc ion energy storage capability of inert MnO cathode by defect engineering

Aqueous zinc ion battery constitutes a safe, stable and promising next-generation energy storage device, but suffers the lack of suitable host compounds for zinc ion storage. Development of a facile way to emerging cathode materials is strongly requested toward superior electrochemical activities and practical applications. Herein, defect engineering, i.e., simultaneous introduction of nitrogen dopant and oxygen vacancy into commercial and low-cost MnO, is proposed as a positive strategy to activate the originally inert phase for kinetically propelling its zinc ion storage capability. Both experimental characterization and theoretical calculations demonstrate that the nitrogen dopant significantly improves the electric conductivity of electrochemical inert MnO. Simultaneously, the oxygen vacancy creates sufficient large inserted channels and available activated adsorption sites for zinc ions storage. These synergistic structural advantages obviously ameliorate the electrochemical performance of inert MnO. Therefore, even without any conductive agent additive, the as-prepared material shows high specific capacity, superb rate capability, prolonged cycling stability and attractive energy density, which are dramatically superior to those of the pristine MnO as well as many other host cathode materials. This work presents fresh insights on the role of defect engineering in the enhancement of the intrinsic electrochemical reactivity of inert cathode, and an effective strategy for scalable fabrication of high-performance cathode for zinc ion battery.

Surface chemical functionality of carbon dots: influence on the structure and energy storage performance of the layered double hydroxide

As a kind of zero-dimensional material, carbon dots (CDs) have become a kind of promising novel material due to their incomparable unique physical and chemical properties. Despite the optical properties of CDs being widely studied, their surface chemical functions are rarely reported. Here we propose an interesting insight into the important role of surface chemical properties of CDs in adjusting the structure of the layered double hydroxide (LDH) and its energy storage performance. It was demonstrated that CDs with positive charge (p-CDs) not only reduce the size of the flower-like LDH through affecting the growth of LDH sheets, but also act as a structure stabilizer. After calcination, the layered double oxide (LDO) maintained the morphology of the LDH and prevented the stacking of layers. And the superiority of the composite in lithium-ion batteries (LIBs) was demonstrated. When used as an anode of LIBs, composites possess outstanding specific capacity, cycle stability and rate performance. It presents the discharge capacity of 1182 mA h g-1 and capacity retention of 94% at the current density of 100 mA g-1 after 100 cycles. Our work demonstrates the important chemical functions of CDs and expands their future applications.

KCl-assisted activation: Moringa oleifera branch-derived porous carbon for high performance supercapacitor

Porous carbons with a high specific surface area (2314–3470 m² g⁻¹) are prepared via a novel KCl-assisted activation strategy for high-performance supercapacitor.

MiR-503 Contributes to Glucocorticoid Sensitivity in Acute Lymphoblastic Leukaemia via Targeting WNT3A

Abnormal accumulation of lymphoblasts in the blood and bone marrow is the main characteristic of acute lymphoblastic leukaemia (ALL). Glucocorticoids are effective drugs for ALL, while glucocorticoid resistance is an obstacle to ALL therapy. MicroRNAs (miRNAs) are implicated in the drug resistance and modulate the response of ALL to glucocorticoids. The role of miR-503 in glucocorticoid sensitivity of ALL was investigated in this study. Firstly, T-leukaemic cells were isolated from patients with ALL. The human ALL cell line (CCRF/CEM) was incubated with dexamethasone to establish a glucocorticoid- resistant ALL cell line (CCRF/CEM-R). Data from MTT showed that IC⁵⁰ (50% inhibitory concentration) of dexamethasone in T-leukaemic cells isolated from glucocorticoid-resistant ALL patients or CCRF/CEM-R was increased compared with IC50 in T-leukaemic cells isolated from glucocorticoid- sensitive ALL patients or CCRF/CEM. MiR- 503 was down-regulated in glucocorticoid-resistant leukaemic cells and CCRF/CEM-R. Secondly, overexpression of miR-503 sensitized CCRF/CEM-R to dexamethasone. Moreover, over-expression of miR- 503 also promoted the sensitivity of ALL cells to dexamethasone. Thirdly, miR-503 bound to WNT3A mRNA and negatively regulated the expression of WNT3A. Over-expression of miR-503 reduced protein expression of nuclear β-catenin, and over-expression of WNT3A attenuated the miR-503 overexpression- induced decrease in nuclear β-catenin. Lastly, the over-expression of miR-503-induced increased sensitivity of ALL-resistant cells and CCRF/ CEM-R to dexamethasone was attenuated by overexpression of WNT3A. In conclusion, miR-503 targeted WNT3A mRNA to sensitize ALL cells to glucocorticoids through inactivation of the Wnt/β-catenin pathway.

Quantitative material analysis using secondary electron energy spectromicroscopy

This paper demonstrates how secondary electron energy spectroscopy (SEES) performed inside a scanning electron microscope (SEM) can be used to map sample atomic number and acquire bulk valence band density of states (DOS) information at low primary beam voltages. The technique uses an electron energy analyser attachment to detect small changes in the shape of the scattered secondary electron (SE) spectrum and extract out fine structure features from it. Close agreement between experimental and theoretical bulk valance band DOS distributions was obtained for six different test samples, where the normalised root mean square deviation ranged from 2.7 to 6.7%. High accuracy levels of this kind do not appear to have been reported before. The results presented in this paper point towards SEES becoming a quantitative material analysis companion tool for low voltage scanning electron microscopy (LVSEM) and providing new applications for Scanning Auger Microscopy (SAM) instruments.

Propelling electrochemical kinetics of transition metal oxide for high-rate lithium-ion battery through in situ deoxidation

To engineer advanced anodes for high-rate lithium-ion battery, rational structural design with insightful understanding of rapid reaction kinetics is important and still highly desirable. In this work, a high-temperature in situ deoxidation strategy is used to propel electrochemical kinetics of NiO through incorporating an intrinsic Ni component. Both theoretical calculation and experimental study demonstrate that the Ni-NiO heterojunction significantly enhances the electronic conductivity and ion diffusion properties. Accordingly, the lithium-ion battery modified with the heterostructured Ni-NiO shows remarkably improved charge transfer efficiency and rate performance, substantially outperforming many reported NiO-based anodes. This work opens up the exploration of heterostructured metal compounds as kinetic regulators for high-rate lithium-ion battery and also enlightens the understanding of defect chemistry in propelling electrochemical reactions.

[A survey on sexual needs and factors of HIV risky sexual behaviors among elderly men at different ages in two communities of Qiandongnan Miao and Dong autonomous prefecture]

Objective: To understand sexual needs and factors of risky sexual behaviors among elderly men at different ages in two communities of Qiandongnan Miao and Dong autonomous prefecture and provide basis for targeted HIV prevention and intervention. Methods: Two communities in the prefecture were selected as study sites. Questionnaire surveys were carried out among elderly men aged 50 and over who visited or consulted in the communities from June to December 2018, and they were tested for HIV and syphilis antibodies. Results: Among 400 elderly men, 209 (52.2%) were 50-64 years old, and 191(47.8%) were above 65 years old. They were mainly Miao people, accounting for 66.3% (265/400), and 235 (58.8%) had an education no more than 6 years. HIV awareness of the two age groups were only 25.8% (54/199) and 26.2% (50/191), respectively. Among those aged 50-64, 142 (68.0%) felt normal sexual desire, and 153 (73.6%) reported penile erections or erections in most cases whenever sex, and 52.9% (110) ejaculated most of the time. HIV prevalence was 1.0% (4/400). Compared with the over 65-year-old group, the proportion of having sex with spouse/stable partners (89.5%, 179/200), proportion of no condom use with their spouse/stable sexual partners during the most recent sex (93.8%, 168/179), proportion of having casual sex (11.0%, 23/209) and commercial sex (3.8%, 8/209) were all higher among 50-64 age group. In comparison to those aged over 65 years old, average monthly income>3 000, and use of sex helper, aged 50-64 (OR=2.70, 95%CI: 1.22-5.95), average monthly income ≤1 000 yuan (OR=2.79, 95%CI: 1.25-6.21), and no use of sex helper (OR=3.78) (95%CI: 1.65-8.67) were related factors of HIV risky sexual behavior last time. Conclusion: Elderly men in the minority prefecture had low HIV awareness. Compared with those≥65 years old, the 50-64 age group had more active sexual behaviors and higher sexual needs. Those from 50-64 age group, with lower economic level and good sexual ability were more likely to have HIV risky sexual behaviors.

Ultralong lifetime and efficient room temperature phosphorescent carbon dots through multi-confinement structure design

Room temperature phosphorescence materials have inspired extensive attention owing to their great potential in optical applications. However, it is hard to achieve a room temperature phosphorescence material with simultaneous long lifetime and high phosphorescence quantum efficiency. Herein, multi-confined carbon dots were designed and fabricated, enabling room temperature phosphorescence material with simultaneous ultralong lifetime, high phosphorescence quantum efficiency, and excellent stability. The multi-confinement by a highly rigid network, stable covalent bonding, and 3D spatial restriction efficiently rigidified the triplet excited states of carbon dots from non-radiative deactivation. The as-designed multi-confined carbon dots exhibit ultralong lifetime of 5.72 s, phosphorescence quantum efficiency of 26.36%, and exceptional stability against strong oxidants, acids and bases, as well as polar solvents. This work provides design principles and a universal strategy to construct metal-free room temperature phosphorescence materials with ultralong lifetime, high phosphorescence quantum efficiency, and high stability for promising applications, especially under harsh conditions.

For room temperature phosphorescence (RTP) materials to reach their potential for optical applications, new materials with improved performance must be realized. Here, the authors report multi-confined carbon dots as high stability RTP materials with long afterglow lifetime & high efficiency.