Mitochondrial DNA has a special structure that is prone to damage resulting in many serious diseases, such as genetic diseases and cancers. Therefore, the rapid and specific monitoring of mitochondrial DNA damage is urgently needed for biological recognition. Herein, we constructed an in situ hydrophobic environment-triggering reactive fluorescence probe named MBI-CN. The fluorophore was 2-styrene-1H-benzo[d]imidazole, and malononitrile was introduced as a core into a molecule to initiate the hydrolysis reaction in the specific environment containing damaged mitochondrial DNA. In this design, MBI-CN conjugates to mitochondrial DNA without causing additional damages. Thus, MBI-CN can be hydrolyzed to generate MBI-CHO in an in situ hydrophobic environment with mitochondrial DNA damage. Meanwhile, MBI-CHO immediately emitted a significative fluorescence signal changes at 437 and 553 nm within 25 s for the damaged mitochondria DNA. Give that the specific and rapid response of MBI-CN does not cause additional damages to mitochondrial DNA, it is a potentially effective detection tool for the real-time monitoring of mitochondrial DNA damage during cell apoptosis and initial assessment of cell apoptosis.
The conceptual process design of novel bioprocesses in biorefinery setups is an important task, which remains yet challenging due to several limitations. We propose a novel framework incorporating superstructure optimization and simulation-based optimization synergistically. In this context, several approaches for superstructure optimization based on different surrogate models can be deployed. By means of a case study, the framework is introduced and validated, and the different superstructure optimization approaches are benchmarked. The results indicate that even though surrogate-based optimization approaches alleviate the underlying computational issues, there remains a potential issue regarding their validation. The development of appropriate surrogate models, comprising the selection of surrogate type, sampling type, and size for training and cross-validation sets, are essential factors. Regarding this aspect, satisfactory validation metrics do not ensure a successful outcome from its embedded use in an optimization problem. Furthermore, the framework’s synergistic effects by sequentially performing superstructure optimization to determine candidate process topologies and simulation-based optimization to consolidate the process design under uncertainty offer an alternative and promising approach. These findings invite for a critical assessment of surrogate-based optimization approaches and point out the necessity of benchmarking to ensure consistency and quality of optimized solutions.
Production cost, capacitance, and electrode materials safety are the key factors to be concerned about for supercapacitors. In this work, a type of carbon nanosheets was produced through the carbonization of tripotassium citrate monohydrate and nitric acidification. Subsequently, a well-designed manganese dioxide/carbon nanosheets composite was synthesized through hydrothermal treating. The carbon nanosheets served as the substrate for growing the manganese dioxide, regulating its distribution, and preventing it from inhomogeneous dimensions and severe agglomeration. Many manganese dioxide nanosheets grew vertically on the numerous functional groups generated on the surface of the carbon nanosheets during acidification. The synergistic combination of carbon nanosheets and manganese dioxide tailors the electrochemical performance of the composite, which benefits from the excellent conductivity and stability of carbon nanosheets. The carbon nanosheets derived from tripotassium citrate monohydrate are conducive to the remarkable performance of manganese dioxide/carbon nanosheets electrode. Finally, an asymmetric supercapacitor with active carbon as the cathode and manganese dioxide/carbon nanosheets as the anode was assembled, achieving an outstanding energy density of 54.68 Wh·kg–1 and remarkable power density of 6399.2 W·kg–1 superior to conventional lead-acid batteries. After 10000 charge-discharge cycles, the device retained 75.3% of the initial capacitance, showing good cycle stability. Two assembled asymmetric supercapacitors in series charged for 3 min could power a yellow light emitting diode with an operating voltage of 2 V for 2 min. This study may provide valuable insights for applying carbon materials and manganese dioxide in the energy storage field.
Copper(I) selenide-nanocrystalline semiconductor was synthesized via one-step mechanochemical synthesis after 5 min milling in a planetary ball mill. The kinetics of synthesis was followed by X-ray powder diffraction analysis and specific surface area measurements of milled 2Cu/Se mixtures. The X-ray diffraction confirmed the orthorhombic crystal structure of Cu2Se with the crystallite size ~25 nm. The surface chemical structure was studied by X-ray photoelectron spectroscopy, whereby the binding energy of the Cu 2p and Se 3d signals corresponded to Cu+ and Se2– oxidation states. Transmission electron microscopy revealed agglomerated nanocrystals and confirmed their orthorhombic structure, as well. The optical properties were studied utilizing ultraviolet-visible spectroscopy and photoluminescence spectroscopy. The direct bandgap energy 3.7 eV indicated a blue-shift phenomenon due to the quantum size effect. This type of Cu2Se synthesis can be easily adapted to production dimensions using an industrial vibratory mill. The advantages of mechanochemical synthesis represent the potential for inexpensive, environmentally-friendly, and waste-free manufacturing of Cu2Se.
Surface functionalization or modification to introduce more oxygen-containing functional groups to biochar is an effective strategy for tuning the physicochemical properties and promoting follow-up applications. In this study, non-thermal plasma was applied for biochar surface carving before being used in contaminant removal and energy storage applications. The results showed that even a low dose of plasma exposure could introduce a high number density of oxygen-functional groups and enhance the hydrophilicity and metal affinity of the pristine biochar. The plasma-treated biochar enabled a faster metal-adsorption rate and a 40% higher maximum adsorption capacity of heavy metal ion Pb2+. Moreover, to add more functionality to biochar surface, biochar with and without plasma pre-treatment was activated by KOH at a temperature of 800 °C. Using the same amount of KOH, the plasma treatment resulted in an activated carbon product with the larger BET surface area and pore volume. The performance of the treated activated carbon as a supercapacitor electrode was also substantially improved by>30%. This study may provide guidelines for enhancing the surface functionality and application performances of biochar using non-thermal-based techniques.
Solvent-based post-combustion capture technologies have great potential for CO2 mitigation in traditional coal-fired power plants. Modelling and simulation provide a low-cost opportunity to evaluate performances and guide flexible operation. Composed by a series of partial differential equations, first-principle post-combustion capture models are computationally expensive, which limits their use in real time process simulation and control. In this study, we propose a first-principle approach to develop the basic structure of a reduced-order model and then the dominant factor is used to fit properties and simplify the chemical and physical process, based on which a universal and hybrid post-combustion capture model is established. Model output at steady state and trend at dynamic state are validated using experimental data obtained from the literature. Then, impacts of liquid-to-gas ratio, reboiler power, desorber pressure, tower height and their combination on the absorption and desorption effects are analyzed. Results indicate that tower height should be designed in conjunction with the flue gas flow, and the gas-liquid ratio can be optimized to reduce the reboiler power under a certain capture target.
Chemical industry is always seeking opportunities to efficiently and economically convert raw materials to commodity chemicals and higher value-added chemical-based products. The life cycles of chemical products involve the procedures of conceptual product designs, experimental investigations, sustainable manufactures through appropriate chemical processes and waste disposals. During these periods, one of the most important keys is the molecular property prediction models associating molecular structures with product properties. In this paper, a framework combining quantum mechanics and quantitative structure-property relationship is established for fast molecular property predictions, such as activity coefficient, and so forth. The workflow of framework consists of three steps. In the first step, a database is created for collections of basic molecular information; in the second step, quantum mechanics-based calculations are performed to predict quantum mechanics-based/derived molecular properties (pseudo experimental data), which are stored in a database and further provided for the developments of quantitative structure-property relationship methods for fast predictions of properties in the third step. The whole framework has been carried out within a molecular property prediction toolbox. Two case studies highlighting different aspects of the toolbox involving the predictions of heats of reaction and solid-liquid phase equilibriums are presented.
To realize renewable energy conversion, it is important to develop low-cost and high-efficiency electrocatalyst for oxygen evolution reaction. In this communication, a novel bijunction CoS/CeO2 electrocatalyst grown on carbon cloth is prepared by the interface engineering. The interface engineering of CoS and CeO2 facilitates a rapid charge transfer from CeO2 to CoS. Such an electrocatalyst exhibits outstanding electrocatalytic activity with a low overpotential of 311 mV at 10 mA∙cm−2 and low Tafel slope of 76.2 mV∙dec–1, and is superior to that of CoS (372 mV) and CeO2 (530 mV) counterparts. And it has long-term durability under alkaline media.
Many scientific efforts have been made to penetrate the blood-brain barrier and target glioblastoma cells, but the outcomes have been limited. More attention should be given to local inhibition of recurrence after glioblastoma resection to meet real medical needs. A biodegradable wafer containing the chemotherapeutics carmustine (1,3-bis(2-chloroethyl)-1-nitrosourea, BCNU) was the only local drug delivery system approved for clinical glioblastoma treatment, but with a prolonged survival time of only two months and frequent side effects. In this study, to improve the sustained release and prolonged therapeutic effect of drugs for inhibiting tumor recurrence after tumor resection, both free BCNU and BCNU- poly (lactic-co-glycolic acid) (the ratio of lactic acid groups to glycolic acid groups is 75/25) nanoparticles were simultaneously loaded into natural extracellular matrix hydrogel from pigskin to prepare BCNU gels. The hydrogel was injected into the resection cavity of a glioblastoma tumor immediately after tumor removal in a fully characterized resection rat model. Free drugs were released instantly to kill the residual tumor cells, while drugs in nanoparticles were continuously released to achieve a continuous and effective inhibition of the residual tumor cells for 30 days. These combined actions effectively restricted tumor growth in rats. Thus, this strategy of local drug implantation and delivery may provide a reliable method to inhibit the recurrence of glioblastoma after tumor resection in vivo.
Uridine diphosphate (UDP)-glucuronosyltransferases (UGTs) are enzymes involved in the biotransformation of important endogenous compounds such as steroids, bile acids, and hormones as well as exogenous substances including drugs, environmental toxicants, and carcinogens. Here, a novel fluorescent probe BDMP was developed based on boron-dipyrromethene (BODIPY) with high sensitivity for the detection UGT1A8. The glucuronidation of BDMP not only exhibited a red-emission wavelength (λex/λem = 500/580 nm), but also displayed an excellent UGT1A8-dependent fluorescence signal with a good linear relationship with UGT1A8 concentration. Based on this perfect biocompatibility and cell permeability, BDMP was successfully used to image endogenous UGT1A8 in human cancer cell lines (LoVo and HCT15) in real time. In addition, BDMP could also be used to visualize UGT1A8 in tumor tissues. These results suggested that BDMP is a promising molecular tool for the investigation of UGT1A8-mediated physiological function in humans.