Strain Effects on Flexible Perovskite Solar Cells.

Flexible perovskite solar cells (f-PSCs) as a promising power source have grabbed surging attention from academia and industry specialists by integrating with different wearable and portable electronics. With the development of low-temperature solution preparation technology and the application of different engineering strategies, the power conversion efficiency of f-PSCs has approached 24%. Due to the inherent properties and application scenarios of f-PSCs, the study of strain in these devices is recognized as one of the key factors in obtaining ideal devices and promoting commercialization. The strains mainly from the change of bond and lattice volume can promote phase transformation, induce decomposition of perovskite film, decrease mechanical stability, etc. However, the effect of strain on the performance of f-PSCs has not been systematically summarized yet. Herein, the sources of strain, evaluation methods, impacts on f-PSCs, and the engineering strategies to modulate strain are summarized. Furthermore, the problems and future challenges in this regard are raised, and solutions and outlooks are offered. This review is dedicated to summarizing and enhancing the research into the strain of f-PSCs to provide some new insights that can further improve the optoelectronic performance and stability of flexible devices.

Probiotic-fermented Qushi decoction alleviates reserpine-induced spleen deficiency syndrome by regulating spleen function and gut microbiota dysbiosis.

BACKGROUND: Spleen deficiency syndrome (SDS) is associated with elevated inflammatory factors and dysregulation of gastrointestinal motility hormones and intestinal microbiota. Qushi decoction (QD), a traditional formula, has not been reported using modern scientific research methods for changes in its probiotic fermented QD (FQD) composition and its potential mechanisms to alleviate SDS. Therefore, the aim of this study was to investigate the splenic protection of FQD in SDS rats by modulating gastrointestinal motility hormones and intestinal microbiota. RESULTS: The results showed that FQD increased total polysaccharides, total protein, total flavonoids and the other active ingredients compared to QD, effectively improved splenic inflammation and apoptosis in SDS rats, and modulated gastrointestinal motility hormones to alleviate diarrhea and other symptoms. In addition, the dysregulation of the gut microbiota was reversed by increasing the levels of Bifidobacterium and decreasing the levels of Escherichia-Shigella and Proteobacteria, which may be related to the regulation of bacterial metabolites to alleviate SDS. CONCLUSION: These results suggest that FQD is an effective formula for improving SDS. Our findings show that FQD beneficial to the implications for the treatment of SDS. © 2023 Society of Chemical Industry.

Analysis of the Induced Stress Fields Around Hydraulic Fractures Considering the Influence of Natural Fractures and Bedding Planes.

Natural fractures (NFs) and bedding planes (BPs) are well developed in shale reservoirs. The propagation of hydraulic fractures (HFs) and the opening of NFs and BPs can produce induced stress fields (ISFs) within the fracturing process, causing interference to the in situ stress field. Aiming at the "stress shadow" effect among HFs in horizontal wells, the calculation models of HFs, BPs, and NFs for induced stress distributions are established based on displacement discontinuity theory, which can quantitatively characterize the composite ISF of the three under different connecting states. In addition, the interference coefficient of stress intensity factor (ICSIF) is introduced to quantitatively evaluate the interference degree of the composite ISF to the propagation of HFs. The results show that: (1) the ISF forms a "tensile stress concentration zone" near the fracture surface to promote the HFs opening and a "compressive stress concentration zone" at the fracture tips to suppress the propagation of HFs; (2) the ISF forms an elliptical effective swept area around the fracture, which is affected by the propagation height of HFs, while NFs or BPs generate local disturbances to the ISF; (3) the in situ stress reverses in the swept area, and the stress reversal interval is related to the in situ stress difference, fracture propagation height, Poisson's ratio, fracture net pressure, and fracture spacing; (4) the reasonable fracture spacing and fracture propagation height of horizontal wells can be determined by the ICSIF. The study can provide theoretical guidance for optimizing the fracture spacing and promoting the uniform propagation of multiple fractures in staged fracturing of horizontal wells.

MXene-Boosted Imine Cathodes with Extended Conjugated Structure for Aqueous Zinc-Ion Batteries.

Organic molecules have been considered promising energy-storage materials in aqueous zinc-ion batteries (ZIBs), but are plagued by poor conductivity and structural instability because of the short-range conjugated structure and low molecular weight. Herein, an imine-based tris(aza)pentacene (TAP) with extended conjugated effects along the CN backbones is proposed, which is in situ injected into layered MXene to form a TAP/Ti3 C2 Tx cathode. Theoretical and electrochemical analyses reveal a selective H+ /Zn2+ co-insertion/extraction mechanism in TAP, which is ascribed to the steric effect on the availability of active CN sites. Moreover, Ti3 C2 Tx , as a conductive scaffold, favors fast Zn2+ diffusion to boost the electrode kinetics of TAP. Close electronic interactions between TAP and Ti3 C2 Tx preserve the structural integrity of TAP/Ti3 C2 Tx during the repeated charge/discharge. Accordingly, the TAP/Ti3 C2 Tx cathode delivers a high reversible capacity of 303 mAh g-1 at 0.04 A g-1 in aqueous ZIBs, which also realizes an ultralong lifetime over 10 000 cycles with a capacity retention of 81.6%. Furthermore, flexible Zn||TAP/Ti3 C2 Tx batteries with a quasi-solid-state electrolyte demonstrate potential application in wearable electronic devices. This work offers pivotal guidance to create highly stable organic electrodes for advanced ZIBs.

Population Pharmacokinetics and Dosing Regimen of Lithium in Chinese Patients With Bipolar Disorder.

Background: Lithium is an effective medication approved for the treatment of bipolar disorder (BD). It has a narrow therapeutic index (TI) and requires therapeutic drug monitoring. This study aimed to conduct a population pharmacokinetics (PPK) analysis of lithium and investigate the appropriateness of the dosing regimen according to different patient characteristics. Methods: A total of 476 lithium concentrations from 268 patients with bipolar disorder were analyzed using nonlinear mixed-effects modeling. Monte Carlo simulations were employed to investigate the influence of covariates, such as weight, creatinine clearance, and daily doses of lithium concentrations, and to determine the individualized dosing regimens for patients. Results: Lithium PK was described by a one-compartment model with first-order absorption and elimination processes. The typical estimated apparent clearance was 0.909 L/h-1 with 16.4% between-subject variability in the 62 kg patients with 116 ml/min creatinine clearance and 600 mg daily doses. To achieve a target trough concentration (0.4-0.8 mmol/L) in the maintenance phase, the regimen of 500 mg than 750 mg daily dose was recommended for patients with renal insufficiency and weighing 100 kg. Conclusion: A PPK model for lithium was developed to determine the influence of patient characteristics on lithium pharmacokinetics. Weight, creatinine clearance, and total daily dose of lithium can affect the drug's clearance. These results demonstrate the nonlinear renal excretion of lithium; hence, dosage adjustments are recommended for patients with renal insufficiency.

Exploring Neurofeedback Training for BMI Power Augmentation of Upper Limbs: A Pilot Study.

Electroencephalography neurofeedback (EEG-NFB) training can induce changes in the power of targeted EEG bands. The objective of this study is to enhance and evaluate the specific changes of EEG power spectral density that the brain-machine interface (BMI) users can reliably generate for power augmentation through EEG-NFB training. First, we constructed an EEG-NFB training system for power augmentation. Then, three subjects were assigned to three NFB training stages, based on a 6-day consecutive training session as one stage. The subjects received real-time feedback from their EEG signals by a robotic arm while conducting flexion and extension movement with their elbow and shoulder joints, respectively. EEG signals were compared with each NFB training stage. The training results showed that EEG beta (12-40 Hz) power increased after the NFB training for both the elbow and the shoulder joints' movements. EEG beta power showed sustained improvements during the 3-stage training, which revealed that even the short-term training could improve EEG signals significantly. Moreover, the training effect of the shoulder joints was more obvious than that of the elbow joints. These results suggest that NFB training can improve EEG signals and clarify the specific EEG changes during the movement. Our results may even provide insights into how the neural effects of NFB can be better applied to the BMI power augmentation system and improve the performance of healthy individuals.

Rapid Preparation of MWCNTs/Epoxy Resin Nanocomposites by Photoinduced Frontal Polymerization.

Due to their excellent mechanical and thermal properties and medium resistance, epoxy/carbon nanotubes and nanocomposites have been widely used in many fields. However, the conventional thermosetting process is not only time- and energy-consuming, but also causes the agglomeration of nanofillers, which leads to unsatisfactory properties of the obtained composites. In this study, multi-walled carbon nanotubes (MWCNTs)/epoxy nanocomposites were prepared using UV photoinduced frontal polymerization (PIFP) in a rapid fashion. The addition of MWCNTs modified by a surface carboxylation reaction was found to enhance the impact strength and heat resistance of the epoxy matrix effectively. The experimental results indicate that with 0.4 wt % loading of modified MWCNTs, increases of 462.23% in the impact strength and 57.3 °C in the glass transition temperature Tg were achieved. A high-performance nanocomposite was prepared in only a few minutes using the PIFP approach. Considering its fast, energy-saving, and environmentally friendly production, the PIFP approach displays considerable potential in the field of the fast preparation, repair, and deep curing of nanocomposites and coatings.

Functional Evaluation of a Force Sensor-Controlled Upper-Limb Power-Assisted Exoskeleton with High Backdrivability.

A power-assisted exoskeleton should be capable of reducing the burden on the wearer's body or rendering his or her work improved and efficient. More specifically, the exoskeleton should be easy to wear, be simple to use, and provide power assistance without hindering the wearer's movement. Therefore, it is necessary to evaluate the backdrivability, range of motion, and power-assist capability of such an exoskeleton. This evaluation identifies the pros and cons of the exoskeleton, and it serves as the basis for its subsequent development. In this study, a lightweight upper-limb power-assisted exoskeleton with high backdrivability was developed. Moreover, a motion capture system was adopted to measure and analyze the workspace of the wearer's upper limb after the exoskeleton was worn. The results were used to evaluate the exoskeleton's ability to support the wearer's movement. Furthermore, a small and compact three-axis force sensor was used for power assistance, and the effect of the power assistance was evaluated by means of measuring the wearer's surface electromyography, force, and joint angle signals. Overall, the study showed that the exoskeleton could achieve power assistance and did not affect the wearer's movements.

Preparation of UV-Curable Low Surface Energy Polyurethane Acrylate/Fluorinated Siloxane Resin Hybrid Coating with Enhanced Surface and Abrasion Resistance Properties.

Low surface energy coatings have gained considerable attention due to their superior surface hydrophobic properties. However, their abrasion resistance and sustainability of surface hydrophobicity are still not very satisfactory and need to be improved. In this work, a series of utraviolet (UV)-curable fluorosiloxane copolymers were synthesized and used as reactive additives to prepare polyurethane acrylate coatings with low surface energy. The effect of the addition of the fluorinated graft copolymers on the mechanical durability and surface hydrophobicity of the UV-cured hybrid films during the friction-annealing treatment cycles was investigated. The results show that introducing fluorosiloxane additives can greatly enhance surface hydrophobicity of the hybrid film. With addition of 2 wt.% fluorosiloxane copolymers, the water contact angle (WCA) value of the hybrid film was almost tripled compared to that of the pristine PU film, increasing from 58° to 144°. The hybrid film also showed enhanced abrasion resistance and could withstand up to about 60 times of friction under a pressure of 20 kPa. The microstructure formed in the annealed film was found to contribute much to achieve better surface hydrophobicity. The polyurethane acrylate/fluorinated siloxane resin hybrid film prepared in this study exhibits excellent potential for applications in the low surface energy field.

A non-enzymatic glucose sensor with enhanced anti-interference ability based on a MIL-53(NiFe) metal-organic framework.

Non-enzymatic glucose sensors are attracting significant attention owing to their low cost, storage convenience and reusability; however, their poor anti-interference caused by their weak selectivity towards glucose limits their practicability. In the present study, a MIL-53(NiFe) metal-organic framework (MOF) was prepared on Ni foam to serve as a self-supported electrode for non-enzymatic glucose detection. Due to the abundant active sites in the MIL-53(NiFe) MOF and its good stability in an alkaline solution, the sensors exhibited a high sensitivity (41.95 mA mM-1 cm-2) and a low detection limit (0.67 µM). Moreover, the molecular sieve effect of the MIL-53(NiFe) MOF led to a remarkable anti-interference ability, even at the interference concentrations of up to 20% glucose, a higher value than that in human serum. In addition, a heat treatment was carried out to remove the residual terephthalic acid in the MOF tunnels, and this promoted the detection linear range to 2-1600 µM. The reusability, reproducibility and long-term stability of the sensors were also studied, and the results implied good practicability of the MIL-53(NiFe) MOF-based sensors. Furthermore, the good practicability of the sensors was verified by testing human serum samples. The results showed the relative standard deviation of 2.73% from the hospital results, and the standard recovery was nearly 100%.

Efficient chiral synthesis by Saccharomyces cerevisiae spore encapsulation of Candida parapsilosis Glu228Ser/(S)-carbonyl reductase II and Bacillus sp. YX-1 glucose dehydrogenase in organic solvents.

BACKGROUND: Saccharomyces cerevisiae AN120 osw2∆ spores were used as a host with good resistance to unfavorable environment. This work was undertaken to develop a new yeast spore-encapsulation of Candida parapsilosis Glu228Ser/(S)-carbonyl reductase II and Bacillus sp. YX-1 glucose dehydrogenase for efficient chiral synthesis in organic solvents. RESULTS: The spore microencapsulation of E228S/SCR II and GDH in S. cerevisiae AN120 osw2∆ catalyzed (R)-phenylethanol in a good yield with an excellent enantioselectivity (up to 99%) within 4 h. It presented good resistance and catalytic functions under extreme temperature and pH conditions. The encapsulation produced several chiral products with over 70% yield and over 99% enantioselectivity in ethyl acetate after being recycled for 4-6 times. It increased substrate concentration over threefold and reduced the reaction time two to threefolds compared to the recombinant Escherichia coli containing E228S and glucose dehydrogenase. CONCLUSIONS: This work first described sustainable enantioselective synthesis without exogenous cofactors in organic solvents using yeast spore-microencapsulation of coupled alcohol dehydrogenases.

Feature Extraction of Shoulder Joint's Voluntary Flexion-Extension Movement Based on Electroencephalography Signals for Power Assistance.

Brain-Machine Interface (BMI) has been considered as an effective way to help and support both the disabled rehabilitation and healthy individuals' daily lives to use their brain activity information instead of their bodies. In order to reduce costs and control exoskeleton robots better, we aim to estimate the necessary torque information for a subject from his/her electroencephalography (EEG) signals when using an exoskeleton robot to perform the power assistance of the upper limb without using external torque sensors nor electromyography (EMG) sensors. In this paper, we focus on extracting the motion-relevant EEG signals' features of the shoulder joint, which is the most complex joint in the human's body, to construct a power assistance system using wearable upper limb exoskeleton robots with BMI technology. We extract the characteristic EEG signals when the shoulder joint is doing flexion and extension movement freely which are the main motions of the shoulder joint needed to be assisted. Independent component analysis (ICA) is used to extract the source information of neural components, and then the average method is used to extract the characteristic signals that are fundamental to achieve the control. The proposed approach has been experimentally verified. The results show that EEG signals begin to increase at 300⁻400 ms before the motion and then decrease at the beginning of the generation of EMG signals, and the peaks appear at about one second after the motion. At the same time, we also confirmed the relationship between the change of EMG signals and the EEG signals on the time dimension, and these results also provide a theoretical basis for the delay parameter in the linear model which will be used to estimate the necessary torque information in future. Our results suggest that the estimation of torque information based on EEG signals is feasible, and demonstrate the potential of using EEG signals via the control of brain-machine interface to support human activities continuously.

A CuNi/C Nanosheet Array Based on a Metal-Organic Framework Derivate as a Supersensitive Non-Enzymatic Glucose Sensor.

Bimetal catalysts are good alternatives for non-enzymatic glucose sensors owing to their low cost, high activity, good conductivity, and ease of fabrication. In the present study, a self-supported CuNi/C electrode prepared by electrodepositing Cu nanoparticles on a Ni-based metal-organic framework (MOF) derivate was used as a non-enzymatic glucose sensor. The porous construction and carbon scaffold inherited from the Ni-MOF guarantee good kinetics of the electrode process in electrochemical glucose detection. Furthermore, Cu nanoparticles disturb the array structure of MOF derived films and evidently enhance their electrochemical performances in glucose detection. Electrochemical measurements indicate that the CuNi/C electrode possesses a high sensitivity of 17.12 mA mM-1 cm-2, a low detection limit of 66.67 nM, and a wider linearity range from 0.20 to 2.72 mM. Additionally, the electrode exhibits good reusability, reproducibility, and stability, thereby catering to the practical use of glucose sensors. Similar values of glucose concentrations in human blood serum samples are detected with our electrode and with the method involving glucose-6-phosphate dehydrogenase; the results further demonstrate the practical feasibility of our electrode.

A Novel Synthetic UV-Curable Fluorinated Siloxane Resin for Low Surface Energy Coating.

Low surface energy materials have attracted much attention due to their properties and various applications. In this work, we synthesized and characterized a series of ultraviolet (UV)-curable fluorinated siloxane polymers with various fluorinated acrylates-hexafluorobutyl acrylate, dodecafluoroheptyl acrylate, and trifluorooctyl methacrylate-grafted onto a hydrogen-containing poly(dimethylsiloxane) backbone. The structures of the fluorinated siloxane polymers were measured and confirmed by proton nuclear magnetic resonance and Fourier transform infrared spectroscopy. Then the polymers were used as surface modifiers of UV-curable commercial polyurethane (DR-U356) at different concentrations (1, 2, 3, 4, 5, and 10 wt %). Among three formulations of these fluorinated siloxane polymers modified with DR-U356, hydrophobic states (91°, 92°, and 98°) were obtained at low concentrations (1 wt %). The DR-U356 resin is only in the hydrophilic state at 59.41°. The fluorine and siloxane element contents were investigated by X-ray photoelectron spectroscopy and the results indicated that the fluorinated and siloxane elements were liable to migrate to the surface of resins. The results of the friction recovering assays showed that the recorded contact angles of the series of fluorinated siloxane resins were higher than the original values after the friction-annealing progressing.

[Glass transition of Chinese medicine extract powder and its application].

Glass transition theory is an important theory in polymer science, which is used to characterize the physical properties. It refers to the transition of amorphous polymer from the glassy state to the rubber state due to heating or the transition from rubber state to glassy state due to cooling. In this paper, the glassy state and glass transition of food and the similar relationship between the composition of Chinese medicine extract powder and food ingredients were described; the determination method for glass transition temperature (Tg) of Chinese medicine extract powder was established and its main influencing factors were analyzed. Meanwhile, the problems in drying process, granulation process and Chinese medicine extract powder and solid preparation storage were analyzed and investigated based on Tg, and then the control strategy was put forward to provide guidance for the research and production of Chinese medicine solid preparation.

Quantitative analysis of gadoxetic acid-enhanced magnetic resonance imaging predicts histological grade of hepatocellular carcinoma.

OBJECTIVE: To confirm the histological grade of hepatocellular carcinoma (HCC) by gadoxetic acid-enhanced MRI. METHODS: Ninety-five HCC patients underwent gadoxetic acid-enhanced MRI before surgical intervention. The correlations among the signal absolute enhancement, contrast enhancement ratio (CER) and tumor histological grade were analyzed. RESULTS: The correlation between CER of tumor-to-liver and the grades of tumor differentiation is the most significant negative. The k-value for the CER of tumor-to-liver and histopathologic analysis is 0.62, which gives evidence of good agreement. CONCLUSION: The quantitative analysis of gadoxetic acid-enhanced MRI can predict the histological grades of small HCCs.

In situ expression of (R)-carbonyl reductase rebalancing an asymmetric pathway improves stereoconversion efficiency of racemic mixture to (S)-phenyl-1,2-ethanediol in Candida parapsilosis CCTCC M203011.

BACKGROUND: Candida parapsilosis (R)-carbonyl reductase (RCR) and (S)-carbonyl reductase (SCR) are involved in the stereoconversion of racemic (R,S)-1-phenyl-1,2-ethanediol (PED) to its (S)-isomer. RCR catalyzes (R)-PED to 2-hydroxyacetophenone (2-HAP), and SCR catalyzes 2-HAP to (S)-PED. However, the stereoconversion efficiency of racemic mixture to (S)-PED is not high because of an activity imbalance between RCR and SCR, with RCR performing at a lower rate than SCR. To realize the efficient preparation of racemic mixture to (S)-PED, an in situ expression of RCR and a two-stage control strategy were introduced to rebalance the RCR- and SCR-mediated pathways. RESULTS: An in situ expression plasmid pCP was designed and RCR was successfully expressed in C. parapsilosis. With respect to wild-type, recombinant C. parapsilosis/pCP-RCR exhibited over four-fold higher activity for catalyzing racemic (R,S)-PED to 2-HAP, while maintained the activity for catalyzing 2-HAP to (S)-PED. The ratio of k cat /K M for SCR catalyzing (R)-PED and RCR catalyzing 2-HAP was about 1.0, showing the good balance between the functions of SCR and RCR. Based on pH and temperature preferences of RCR and SCR, a two-stage control strategy was devised, where pH and temperature were initially set at 5.0 and 30 °C for RCR rapidly catalyzing racemic PED to 2-HAP, and then adjusted to 4.5 and 35 °C for SCR transforming 2-HAP to (S)-PED. Using these strategies, the recombinant C. parapsilosis/pCP-RCR catalyzed racemic PED to its (S)-isomer with an optical purity of 98.8 % and a yield of 48.4 %. Most notably, the biotransformation duration was reduced from 48 to 13 h. CONCLUSIONS: We established an in situ expression system for RCR in C. parapsilosis to rebalance the functions between RCR and SCR. Then we designed a two-stage control strategy based on pH and temperature preferences of RCR and SCR, better rebalancing RCR and SCR-mediated chiral biosynthesis pathways. This work demonstrates a method to improve chiral biosyntheses via in situ expression of rate-limiting enzyme and a multi-stage control strategy to rebalance asymmetric pathways.

[Application of three-dimensional laparoscopic cholecystectomy for complicated gallstone disease].

OBJECTIVE: To investigate the clinical value of three-dimensional (3D) laparoscopic cholecystectomy in the treatment of complicated gallstone disease. METHODS: From March 2014 to March 2015, 46 patients underwent cholecystectomy for complicated gallstone disease under 3D laparoscopy (3D group) and 43 received 2D laparoscopic cholecystectomy (2D group). The surgical data including the operative time, intraoperative blood loss, the rate of conversion to open laparotomy, recovery time of postoperative bowel motion and hospital stay were compared between the 2 groups. RESULTS: Laparoscopic cholecystectomy was successfully completed in 43 patients in 3D group and in 39 patients in 2D group, and the rates of conversion to open laparotomy were similar between the two groups (P>0.05). The median operation time was significantly shorter in 3D group than in 2D group (50.5∓15.2 vs 65.4∓18.1 min, P<0.05), and the median volume of intraoperative blood loss was significantly smaller in 3D group (34.1∓13.6 vs 44.5∓22.3 mL, P>0.05). No significant differences were found in the recovery time of postoperative bowel motion and postoperative hospital stays between the two groups (P>0.05). CONCLUSION: 3D laparoscopy, which provides three-dimensional vision with a good sense of depth to allow precise surgical manipulation, can shorten the operation time and reduce the rate of conversion to open laparotomy for patients undergoing 3D laparoscopic cholecystectomy for complicated gallstone disease.