Highly Efficient Wavelength-Resolved Electrochemiluminescence of Carbon Nitride Films for Ultrasensitive Multiplex MicroRNA Detection.

The development of electrochemiluminescence (ECL) emitters of different colors with high ECL efficiency (ΦECL) is appealing yet challenging for ultrasensitive multiplexed bioassays. Herein, we report the synthesis of highly efficient polymeric carbon nitride (CN) films with fine-tuned ECL emission from blue to green (410, 450, 470, and 525 nm) using the precursor crystallization method. More importantly, naked eye-observable and significantly enhanced ECL emission was achieved, and the cathodic ΦECL values were ca. 112, 394, 353, and 251 times those of the aqueous Ru(bpy)3Cl2/K2S2O8 reference. Mechanism studies showed that the density of surface-trapped electrons, the associated nonradiative decay pathways, and electron-hole recombination kinetics were crucial factors for the high ΦECL of CN. Based on high ΦECL and different colors of ECL emission, the wavelength-resolved multiplexing ECL biosensor was constructed to simultaneously detect miRNA-21 and miRNA-141 with superior low detection limits of 0.13 fM and 25.17 aM, respectively. This work provides a facile method to synthesize wavelength-resolved ECL emitters based on metal-free CN polymers with high ΦECL for multiplexed bioassays.

Carbon Nitride-Based Heterojunction Photoelectrodes with Modulable Charge-Transfer Pathways toward Selective Biosensing.

Photoelectrochemical (PEC) sensing enables the rapid, accurate, and highly sensitive detection of biologically important chemicals. However, achieving high selectivity without external biological elements remains a challenge because the PEC reactions inherently have poor selectivity. Herein, we report a strategy to address this problem by regulating the charge-transfer pathways using polymeric carbon nitride (pCN)-based heterojunction photoelectrodes. Interestingly, because of redox reactions at different semiconductor/electrolyte interfaces with specific charge-transfer pathways, each analyte demonstrated a unique combination of photocurrent-change polarity. Based on this principle, a pCN-based PEC sensor for the highly selective sensing of ascorbic acid in serum against typical interferences, such as dopamine, glutathione, epinephrine, and citric acid was successfully developed. This study sheds light on a general PEC sensing strategy with high selectivity without biorecognition units by engineering charge-transfer pathways in heterojunctions on photoelectrodes.

High-Strength, Freeze-Resistant, Recyclable, and Biodegradable Polyvinyl Alcohol/Glycol/Wheat Protein Complex Organohydrogel for Wearable Sensing Devices.

The application of flexible wearable sensing devices based on conductive hydrogels in human motion signal monitoring has been widely studied. However, conventional conductive hydrogels contain a large amount of water, resulting in poor mechanical properties and limiting their application in harsh environments. Here, a simple one-pot method for preparing conductive hydrogels is proposed, that is, polyvinyl alcohol (PVA), wheat protein (WP), and lithium chloride (LiCl) are dissolved in an ethylene glycol (EG)/water binary solvent. The obtained PVA/EG/WP (PEW) conductive organohydrogel has good mechanical properties, and its tensile strength and elongation at break reach 1.19 MPa and 531%, respectively, which can withstand a load of more than 6000 times its own weight without breaking. The binary solvent system composed of EG/water endows the hydrogel with good frost resistance and water retention. PEW organohydrogel as a wearable strain sensor also has good strain sensitivity (GF = 2.36), which can be used to detect the movement and physiological activity signals in different parts of the human body. In addition, PEW organohydrogels exhibit good degradability, reducing the environmental footprint of the flexible sensors after disposal. This research provides a new and viable way to prepare a new generation of environmentally friendly sensors.

Construction of Carbon Dots with Wavelength-Tunable Electrochemiluminescence and Enhanced Efficiency.

Tuning the electrochemiluminescence (ECL) wavelength of carbon dots (CDs) with enhanced efficiency is essential for multiplexed biosensing, bioimaging, and energy applications but remains challenging. Herein, we reported a facile route to finely modulate the ECL wavelength of CDs from 425 to 645 nm, the widest range ever reported, along with a more than 5-fold enhancement of ECL efficiency via phosphorous (P) incorporation. The molecular mechanism was explored experimentally and theoretically, which revealed the unusual dual roles of P dopants in the form of P-C and P-O bonding, that is, importing shallow trapping states and promoting an effective intramolecular charge transfer. This work would allow unlocking the key factors of ECL kinetics for heteroatom-doped CDs appearing out of reach and open a new avenue for the rational design of nanocarbon for desirable applications.

All optical half-adder/subtractor using photonic-crystal-based nonlinear cavities.

In this paper, we aim to design a compact structure that can work both as an optical adder and subtractor. Also, as far as we know, one of the main disadvantages of previous optical adders or subtractors is that, inside a single structure, the levels of optical intensity for logic 1 at different output ports are different. In this work, we aim to solve this issue, too. For this purpose, two separate structures were designed for the half-adder and half-subtractor. The final structure was realized by combining these structures and adding an extra control port. When the control port is 0, the structure can work as an optical half-adder; however, when the control port is 1, the proposed structure can work as an all optical half-subtractor. The simulation results show that the rise time and ON/OFF contrast ratio are about 1.5 ps and 18.3 dB, respectively. Also the simulation results prove that the output levels for logic at all the output ports are at similar levels.

Extended Conjugation Tuning Carbon Nitride for Non-sacrificial H2 O2 Photosynthesis and Hypoxic Tumor Therapy.

Artificial photocatalysis offers a clean approach for producing H2 O2 . However, the poor selectivity and activity of H2 O2 production hamper traditional industrial applications and emerging photodynamic therapy (PDT)/chemodynamic therapy (CDT). Herein, we report a C5 N2 photocatalyst with a conjugated C=N linkage for selective and efficient non-sacrificial H2 O2 production in both normoxic and hypoxic systems. The strengthened delocalization of π-electrons by linkers in C5 N2 downshifted the band position, thermodynamically eliminating side H2 evolution reaction and kinetically promoting water oxidation. As a result, C5 N2 had a competitive solar-to-chemical conversion efficiency of 0.55 % in overall H2 O2 production and exhibited by far the highest activity under hypoxic conditions (698 µM h-1 ). C5 N2 was further applied to hypoxic PDT/CDT with outstanding performance in apparent cancer cell death and synchronous bioimaging. The study sheds light on the photosynthesis of H2 O2 by carbon nitrides for health applications.

Author Correction: AZD9291 inactivates the PRC2 complex to mediate tumor growth inhibition.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Use of Interferon-γ release assay for the diagnosis of female genital tuberculosis in Northwest China.

BACKGROUND: Female genital tuberculosis (FGTB) is one of the major causes of infertility. However, nonspecific manifestations and the lack of easy access to gold-standard diagnostic test render a diagnostic difficult for FGTB. The objective of this study was to determine T-SPOT.TB (an interferon-γ release assay, IGRA) performance in patients with FGTB. METHODS: A total of 213 female patients with validated T-SPOT.TB results were recruited in this retrospective study. Among which, 103 were confirmed FGTB, and 110 were excluded from tuberculosis (control). Of the confirmed FGTB patients, 52 were confirmed by microbiologically/histopathologically examination, while the remaining 51 were clinically confirmed (successfully responsive to anti-tuberculosis treatment). T-SPOT.TB test was performed in both FGTB and control group during the diagnostic procedure. RESULTS: The overall sensitivity and specificity of T-SPOT.TB were 86.41% and 75.45% respectively. Sensitivity of T-SPOT.TB was significantly higher when compared with conventional tuberculosis diagnostic tests. Moreover, T-SPOT.TB test using pelvic effusion (PE) showed higher sensitivity than using corresponding peripheral blood (PB) (94.44% vs 72.22%, P < 0.001). Mean value of spot forming cells (SFCs) of T-SPOT.TB using PE was significantly higher than that of PB in FGTB group (193 (IQR 105-280) SFCs/2.5 × 105 PEMCs vs 71 (IQR 36-107) SFCs/2.5 × 105 PBMCs, P = 0.01), while this was not detected in control group (11 (IQR 0-22) SFCs/2.5 × 105 PEMCs vs 9 (IQR 0-18) SFCs/2.5 × 105 PBMCs, P = 0.77). CONCLUSION: These results demonstrated that T-SPOT.TB, especially PE T-SPOT.TB, is an useful adjunct in FGTB diagnosis.

Timescale correlation of shallow trap states increases electrochemiluminescence efficiency in carbon nitrides.

Highly efficient interconversion of different types of energy plays a crucial role in both science and technology. Among them, electrochemiluminescence, an emission of light excited by electrochemical reactions, has drawn attention as a powerful tool for bioassays. Nonetheless, the large differences in timescale among diverse charge-transfer pathways from picoseconds to seconds significantly limit the electrochemiluminescence efficiency and hamper their broad applications. Here, we report a timescale coordination strategy to improve the electrochemiluminescence efficiency of carbon nitrides by engineering shallow electron trap states via Au-N bond functionalization. Quantitative electrochemiluminescence kinetics measurements and theoretic calculations jointly disclose that Au-N bonds endow shallow electron trap states, which coordinate the timescale of the fast electron transfer in the bulk emitter and the slow redox reaction of co-reagent at diffusion layers. The shallow electron trap states ultimately accelerate the rate and kinetics of emissive electron-hole recombination, setting a new cathodic electrochemiluminescence efficiency record of carbon nitrides, and empowering a visual electrochemiluminescence sensor for nitrite ion, a typical environmental contaminant, with superior detection range and limit.

Preparation of Nano-Sized C-S-H and Its Acceleration Mechanism on Portland Cement Hydration at Different Temperatures.

Nano-sized C-S-H, a promising early strength agent, can accelerate the hydration rate of Portland cement and increase the early compressive strength of cement-based composites effectively. Nano-sized C-S-H suspensions with different contents of effective constituent and size distributions were prepared by a convenient coprecipitation method and the microstructures were analyzed by Zeta potential, XRD and FT-IR. The exothermic heat, early mechanical properties, hydration degree and hydration products of cement with/without nano-sized C-S-H cured at different temperatures were studied by hydration exothermic, XRD, SEM and TG analysis. Nano-sized C-S-H with semi-crystalline structures was prepared, and the size of the nano-sized C-S-H seeds showed an obvious increase with an increase in theoretical concentration, and slight precipitation in the suspension was observed when the theoretical concentration was 2%. The XRD, TG and SEM analyses showed that nano-sized C-S-H expedites the reaction of C3S in the first 24 h; therefore, the hydration induction period is obviously shortened. The 8 h, 16 h and 24 h compressive strength of mortars containing nano-sized C-S-H increased by 176.0%, 145.6% and 43.9%, respectively, compared with the reference mortar. The enhancement effects of nano-sized C-S-H at 10 °C were lower than that at 20 °C.

Adaptable graphitic C6N6-based copper single-atom catalyst for intelligent biosensing.

Self-adaptability is highly envisioned for artificial devices such as robots with chemical noses. For this goal, seeking catalysts with multiple and modulable reaction pathways is promising but generally hampered by inconsistent reaction conditions and negative internal interferences. Herein, we report an adaptable graphitic C6N6-based copper single-atom catalyst. It drives the basic oxidation of peroxidase substrates by a bound copper-oxo pathway, and undertakes a second gain reaction triggered by light via a free hydroxyl radical pathway. Such multiformity of reactive oxygen-related intermediates for the same oxidation reaction makes the reaction conditions capable to be the same. Moreover, the unique topological structure of CuSAC6N6 along with the specialized donor-π-acceptor linker promotes intramolecular charge separation and migration, thus inhibiting negative interferences of the above two reaction pathways. As a result, a sound basic activity and a superb gain of up to 3.6 times under household lights are observed, superior to that of the controls, including peroxidase-like catalysts, photocatalysts, or their mixtures. CuSAC6N6 is further applied to a glucose biosensor, which can intelligently switch sensitivity and linear detection range in vitro.

Study on Carbonation Resistance of Polymer-Modified Sulphoaluminate Cement-Based Materials.

The use of tricyclic copolymer latex (AMPS) can effectively improve the carbonation resistance of sulphoaluminate cement. This paper investigated polymer AMPS and polycarboxylic acid to modify sulphoaluminate cement materials by exploring the carbonation level of sulphoaluminate cement paste and mortar and the strength before and after carbonation. Then, the optimal dosage of polymer and polycarboxylic acid was obtained so that the carbonation resistance of sulphoaluminate cement reached the best state. The compressive strength was significantly improved by adding AMPS for sulphoaluminate cement paste and mortar. After carbonation, the strength decreased and combined with the carbonation level; it was concluded that the carbonation resistance of sulphoaluminate cement materials was the best when the optimal dosage of AMPS and polycarboxylic acid was 5% and 1.8%, respectively. Due to the addition of AMPS, the hydrated calcium aluminosilicate (C-A-S-H) and hydrated calcium silicate (C-S-H) gels, generated by the hydration of sulphoaluminate cement and the surface of unreacted cement particles, are wrapped by AMPS particles. The water is discharged through cement hydration. The polymer particles on the surface of the hydration product merge into a continuous film, which binds the cement hydration product together to form an overall network structure, penetrating the entire cement hydration phase and forming a polymer cement mortar with excellent structural sealing performance. To prevent the entry of CO2 and achieve the effect of anti-carbonation, adding polycarboxylic acid mainly improves the sample's internal density to achieve the anti-carbonation purpose.

Oxygen-regulated carbon quantum dots as an efficient metal-free electrocatalyst for nitrogen reduction.

An electrocatalytic nitrogen reduction reaction under ambient conditions provides a wonderful blueprint for the conversion of nitrogen to ammonia. However, current research on ammonia synthesis is mainly focused on metal-based catalysts. It is still a great challenge to realize the effective activation of N2 on non-metallic catalysts. Herein, carbon quantum dots are reported to reduce dinitrogen to ammonia under ambient conditions. Benefiting from its numerous defect sites, this metal-free catalyst shows excellent catalytic performance in 0.1 M HCl with a faradaic efficiency of 17.59%. In addition, both experimental and theoretical results confirm that the catalytic performance of the catalyst can be improved by appropriately controlling the oxygen content of samples at different temperatures, and the utmost ammonia yield is 134.08 µg h-1 mg-1cat., which is almost three times higher than that of a reported metal-free material. The proposed oxygen regulation provides a new method to optimize the surface properties of metal-free catalysts for ammonia synthesis.

Photoelectron Storages in Functionalized Carbon Nitrides for Colorimetric Sensing of Oxygen.

Colorimetric sensors have been widely used for centuries across diverse fields, thanks to their easy operation and uncompromisingly high sensitivity with no need for electricity. However, it is still a great challenge for conventional chromogenic systems to perform multiple measurements meanwhile maintaining high robustness. Here, we reported that carbon nitrides (CNs), the raw materials that are abundant, structure-tunable, and stable semiconductors with photoelectron storage capability, can be developed as a chromogenic system for colorimetric sensors. Beyond conventional metal oxides that only demonstrated a single blue-color switch after photoelectron storage, CN exhibited a multicolor switch under identical conditions owing to the unusual multiple photoelectron storage pathways. Mechanism studies revealed cyano and carbonyl groups in CN crucially elongated the centroid distance of electrons/holes, which exclusively stabilized the specific excited states that have different light absorption; meanwhile, the counter cations strengthened these processes. As a result, O2, a proof-of-concept analyte, was quantitatively detected by the CN-derived colorimetric sensor, showing high reversibility in hundreds of cycles and adaptable sensitivity/detection range, outperforming most reported and commercial oxygen sensors. These intriguing features of CN are highly envisioned for the next generation of colorimetric sensors, especially in developing countries or fieldworks, to improve the detection reliability and lower the sensing cost.

Lymphocyte blood levels that remain low can predict the death of patients with COVID-19.

ABSTRACT: The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been rapidly spreading on a global scale and poses a great threat to human health. However, efficient indicators for disease severity have not been fully investigated. Here, we aim to investigate whether dynamic changes of lymphocyte counts can predict the deterioration of patients with COVID-19.We collected data from 2923 patients with laboratory-confirmed COVID-19. Patients were then screened, and we focused on 145 severe cases and 60 critical cases (29 recovered cases, 31 deaths). The length of hospitalization was divided into five time points, namely admission, 25%, 50%, 75% and discharge or death, according to the principle of interquartile distance. A series of laboratory findings and clinical data were collected and analyzed during hospitalization. The results showed that there were differences in levels of leukocytes, neutrophils and lymphocytes at almost every time point in the severe cases and 60 critical cases (29 recovered cases, 31 deaths). Further analysis showed that 70.2% of the COVID-19 cases had low circulating lymphocyte count, of which 64.1% were severe cases and 85.0% were critical cases (75.9% recovered cases and 93.5% died). Moreover, the lymphocyte count in dead cases was significantly lower than that of critical cases who recovered, at almost every time point in the critical groups. We also divided critical patients into group A (<1.1 × 109/L) and group B (>1.1 × 109/L) according to number of lymphocytes. Through survival analysis, we found that there was no significant difference in survival between group A and group B at admission (P = .3065). However, the survival rate according to lymphocyte levels in group A was significantly lower than that of group B at 25% hospital stay (on average day 6.5), 50% and 75% time points (P < .001).Lymphocyte counts that remain lower after the first week following symptom onset are highly predictive of in-hospital death of adults with COVID-19. This predictor may help clinicians identify patients with a poor prognosis and may be useful for guiding clinical decision-making at an early stage.

Comparison in efficacy and safety of forceps biopsy for peripheral lung lesions guided by endobronchial ultrasound-guided sheath (EBUS-GS) and electromagnetic navigation bronchoscopy combined with EBUS (ENB-EBUS).

Endobronchial ultrasound-guided sheath (EBUS-GS) and electromagnetic navigation bronchoscopy combined with EBUS (ENB-EBUS) are two diagnostic methods used to obtain lung tissue for biopsy of peripheral lung lesions. This study retrospectively summarized the case data of patients who underwent EBUS-GS or ENB-EBUS, both procedures performed at the respiratory endoscopy center of Tangdu Hospital, and the study compared the diagnostic efficacy and complications of the two methods. The study included 93 patients who underwent EBUS-GS and 26 who underwent ENB-EBUS. The diagnostic rates of EBUS-GS and ENB-EBUS were 71.1% and 65.4%, respectively, with no statistical difference (P=0.581). Furthermore, 89.2% of patients in the EBUS-GS group were diagnosed with malignant disease, which was significantly higher than 23.5% diagnosed with malignant disease in the ENB-EBUS group (P=0.00). An analysis of the factors influencing the diagnosis rate showed that the diagnosis rate of EBUS-GS in cases with bronchial signs was 82.5%, which was significantly higher than the 42.9% in the cases in the ENB-EBUS group with bronchial signs (P<0.05). An analysis of the complications showed that the incidence of complications in the EBUS-GS group was 8.4%, and the incidence of complications in the ENB-EBUS group was 3.8%, with no statistical difference (P>0.05). Both EBUS-GS and ENB-EBUS can be used for the diagnosis of peripheral pulmonary disease. However, the diagnostic rate of EBUS-GS is significantly higher than ENB-EBUS in cases with bronchial signs associated with the lesion, and the diagnostic rate of ENB-EBUS in cases with no bronchial signs was higher than that of EBUS-GS with no statistical difference.

Ti3C2Tx MXene-derived TiO2/C-QDs as oxidase mimics for the efficient diagnosis of glutathione in human serum.

Nanozyme-based colorimetry was suggested to be a rapid method for biomarker (e.g. glutathione) detection, but this method suffers from lack of efficiency and low-toxicity nanozymes till now. Herein, quantum dots of TiO2 loaded on carbon (TiO2/C-QDs) oxidase-like nanozymes were prepared via a hydrothermal treatment of tiny and few-layered Ti3C2Tx MXene nanosheets, which possess abundant thermodynamic metastable Ti atoms on MXene margins as raw materials for the preparation of TiO2/C-QDs. The oxygen vacancy in TiO2 on the surface of the carbon matrix can facilitate O2 adsorption in the solution and generate reactive oxygen species (ROS), thereby quickly oxidizing 3,3',5,5'-tetramethylbenzidine (TMB) to its oxidized form (TMBox) in the absence of H2O2. After adding glutathione (GSH), TMBox was able to be restored to TMB, which resulted in a corresponding decrease in the UV-vis absorbance value at 652 nm. Furthermore, this assay possesses good selectivity, excellent specificity and high sensitivity (limit of detection: 0.2 µM), which made it possible to efficiently detect GSH in complex biological samples such as human serum.

Ultra-efficient electromagnetic wave absorption with ethanol-thermally treated two-dimensional Nb2CTx nanosheets.

Nb2CTx, an emerging type of MXene, should be a promising electromagnetic wave (EMW) absorbing material to overcome the EMW pollution nowadays due to its unique layered structure and extremely thin monolayer thickness, but was lack of systematic study till now. Meanwhile, Nb2CTx nanosheets obtained upon HF etching of Nb2AlC MAX was unfortunately found with limited absorption performance due to its mainly dielectric loss mechanism herein. Therefore, the Nb2CTx nanosheets were further treated with solvothermal strategy in various solvents. As a result, the absorption performance of the as-treated Nb2CTx nanosheets could be significantly improved, while the ones in ethanol showed much more superior absorption capability, especially in the low-frequency band (2.0-4.0 GHz). The minimum reflection loss value could reach -52.2 dB at 3.93 GHz with the thickness of only 2.90 mm, indicating more than 99.999% EMW was absorbed. These should be due to the multi-loss mechanism including dielectric, interfacial, and multiple reflection ones resulting from the enlarged interlayer spacing, and increased surface functional groups on the Nb2CTx nanosheets upon the ethanol-based solvothermal treatment.

Autophagy contributes to dasatinib-induced myeloid differentiation of human acute myeloid leukemia cells.

A breakthrough in clinical oncology was achieved as All-trans-retinoic acid (ATRA) sparked intensive differentiation therapy research. However, differentiation therapy is limited because ATRA is the sole efficient agent. Dasatinib is reported to induce myeloid differentiation of acute myeloid leukemia (AML) cells in vitro, but its mechanism remains unclear. Furthermore, the ability of dasatinib to cause differentiation of AML cells has not yet been proven. We assessed the contribution of autophagy to dasatinib-induced differentiation of AML cells. We found that dasatinib induces myeloid differentiation of AML cells accompanied with autophagy induction. Pharmacological inhibition of autophagy by 3-MA, Wortmannin, LY294002 and chloroquine block dasatinib-induced AML cell differentiation, whereas the induction of autophagy by rapamycin enhances AML cell differentiation. Our results suggest that retinoic acid receptors alpha (RARα) may not be involved in dasatinib-induced differentiation. In addition, we further illustrated that even low concentration of dasatinib can enhance ATRA-induced differentiation capability through initiation of autophagy. Taken together, we conclude that autophagy enhances the dasatinib-induced differentiation, which may provide theoretical support for developing dasatinib as a promising strategy for future differentiation therapy in AML patients.