Choline Derivative as a Multifunctional Interfacial Bridge through Synergistic Effects for Improving the Efficiency and Stability of Perovskite Solar Cells.

The interfacial carrier non-radiative recombination caused by buried defects in electron transport layer (ETL) material and the energy barrier severely hinders further improvement in efficiency and stability of perovskite solar cells (PSCs). In this study, the effect of the SnO2 ETL doped with choline chloride (CC), acetylcholine chloride (AC), and phosphocholine chloride sodium salt (PCSS) are investigated. These dopants modify the interface between SnO2 ETL and perovskite layer, acting as a bridge through synergistic effects to form uniform ETL films, enhance the interface contact, and passivate defects. Ultimately, compared with CC (which with ─OH) and AC (which with C═O), the PCSS with P═O and sodium ions groups is more beneficial for improving performance. The device based on PCSS-doped SnO2 ETL achieves an efficiency of 23.06% with a high VOC of 1.2 V, which is considerably higher than the control device (20.55%). Moreover, after aging for 500 h at a temperature of 25 °C and relative humidity (RH) of 30-40%, the unsealed device based on SnO2 -PCSS ETL maintains 94% of its initial efficiency, while the control device only 80%. This study provides a meaningful reference for the design and selection of ideal pre-buried additive molecules.

The effect of perceived stress on social isolation in young and middle-aged maintenance haemodialysis patients: A polynomial regression and response surface analysis.

Patients on maintenance haemodialysis (MHD) face social isolation due to the far-reaching effects of their disease and treatment. Based on the Transactional Model of Stress and Coping, we analysed the relationship between perceived stress and social isolation in patients, and the mediating role of internal health-related locus of control (IHLC) from the perspective of co-existence of perceived helplessness (HEL) and perceived self-efficacy (SEL). We used structured questionnaires to investigate 332 cases of young and middle-aged MHD patients in four tertiary hospitals in Guangdong, China. Polynomial regression and response surface analysis were conducted, along with tests of mediating effects on the data. The research was based on STROBE guidelines. The results showed that perceived stress is significantly and positively associated with social isolation. When the HEL and SEL of perceived stress were congruent, the joint effect of the two was in a positive curvilinear relationship to social isolation, when the two were incongruent, the risk of social isolation was lower for "low HEL-high SEL" patients compared to the "high HEL-low SEL" combination. The more congruent in HEL -SEL, the lower the risk of social isolation for the patients, with the IHLC playing a mediating role in this association. This study reveals that the coexistence of perceived stress's HEL and SEL affects social isolation through congruent and incongruent matching mechanism, providing additional explanations for the mechanism of occurrence of patients' social isolation.

Heterologous expression and characterization of an M4 family extracellular metalloprotease for detergent application.

Proteolytic enzymes stand out as the most widely employed category utilized in manufacturing industry. A new protease was separated from Planococcus sp.11815 strain and named as nprS-15615 in this research. The gene of this protease has not been reported, and its enzymatic properties have been studied for the first time. To enhance enzyme production, the Planococcus sp. protease gene was expressed in Bacillus licheniformis 2709. The expression level of nprS-15615 was observed under the control of regulatory elements PaprE. nprS-15615 protease activity reached 1186.24±32.87 U/mL after 48 hours of cultivation in shake flasks which was nearly four times the output of the original bacteria (291.38±25.73U/mL). The optimum temperature and pH of the recombinant protease were 30 ℃ and 8.0, respectively.The enzyme exhibited the highest capacity for hydrolyzing casein and demonstrated resilience towards a NaCl concentration of 10.0% (wt/v). Furthermore, in the presence of 0.5% surfactants, the recombinant protease activity can maintain above 75%, and with the existence of 0.5% liquid detergents, there was basically no loss of enzyme activity which indicated that nprS-15615 had good compatibility with surfactants and liquid detergents. In addition, npS-15615 performed well in the washing experiment, and the washing effect at 20 ℃ can be significantly improved by adding crude enzyme solution in the washing process.

Synergistic Surface Defect Passivation of Ionic Liquids for Efficient and Stable MAPbI3-Based Inverted Perovskite Solar Cells.

Organic-inorganic hybrid perovskite solar cells are fabricated using polycrystalline perovskite thin films, which possess high densities of point and surface defects. The surface defects of perovskite thin films are the key factors that affect the device performance. Therefore, the reduction of harmful defects is the primary task for improving device performance. Therefore, in this study, high-quality perovskite thin films are prepared using an ionic liquid, dithiocarbamate diethylamine (DADA), to passivate the interface. The electron-rich sulfur atom in the DADA molecule chelates with the uncoordinated lead ion in the perovskite films, and the diethylammonium cation forms a hydrogen bond with the free iodine ion, which further improves the passivation. The synergistic passivation and improved morphology of the perovskite thin films substantially reduce the number of charged defects on the film surface and prolong the carrier lifetime. In addition, the DADA surface treatment increases the work function of the perovskite film, which is beneficial for carrier transport. Under standard solar-lighting conditions, the power conversion efficiency (PCE) of the device increases from 19.13 to 21.36%, and the fill factor is as high as 83.17%. Owing to both the hydrophobicity of DADA molecules and the passivation of ion defects, the PCE of the device remains above 80%, even for the device stored for 500 h in air at a relative humidity of 65%, and the device stability is substantially improved.

Electrochemical degradation of acrylic acid using Ti/Ta2O5-IrO2 electrode.

Acrylic acid (AA) is widely used as a raw material in the industrial production of various chemicals. Its extensive use has produced environmental problems that need to be solved. The Ti/Ta2O5-IrO2 electrode, a type of dimensionally stable anode, was used to investigate the electrochemical deterioration of AA. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis showed that IrO2 existed as an active rutile crystal and as a TiO2-IrO2 solid solution in Ti/Ta2O5-IrO2 electrode with a corrosion potential of 0.212 V and chlorine evolution potential of 1.30 V. The effects of current density, plate spacing, electrolyte concentration, and initial concentration on the electrochemical degradation of AA were investigated. Response surface methodology (RSM) was used to determine the ideal degradation conditions: current density 22.58 mA cm-2, plate spacing 2.11 cm, and electrolyte concentration 0.07 mol L-1, and the highest degradation rate reached was 95.6%. Free radical trapping experiment verified that reactive chlorine played a dominant role in the degradation of AA. The degradation intermediates were analyzed by GC-MS.

Multifunctional Molecule Assists Passivate Method to Simultaneously Improve the Efficiency and Stability of Perovskite Solar Cells.

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has been greatly improved recently. However, in organic-inorganic polycrystalline perovskite films many defects inevitably exist, which limits the PCE and stability of PSCs. Herein, a small organic molecule 2-chlorothiazole-4-carboxylic acid (SN) is spin coated on a perovskite film to enhance the performance of PSCs. We find that the multifunctional molecule SN reacts with under-coordinated Pb2+ ions and I- vacancies because of the presence of the sulfur and nitrogen donor atoms, and the -COOH groups, which are conducive to suppressing charge recombination and passivating defects. Even more, the introduction of the SN layer can effectively adjust the energy level alignment, which is conducive to the separation and extraction of charge carriers in PSCs. Therefore, devices with SN modification show a champion PCE of 22.55 %. Besides, PSCs with SN show impressive stability, retaining 96 % of its initial PCE after storage in ambient air for 500 h.

Potential for selective oxidation of aniline in soil washing effluent by active chlorine and testing its practicality.

Recovery of surfactants in the soil washing effluent (SWE) can significantly reduce the cost of the soil washing (SW) technology. This paper consists of two parts experiments. The first part constructed a selective oxidation system of active chlorine by electrochemical technology to treat SWE. Three factors, current density, NaCl concentration and TW 80 to aniline concentration ratio (T/A), were set up for a total of nine sets of experiments after orthogonal design. The results of ANOVA analysis and visual analysis showed that the NaCl concentration greatly affected the aniline removal efficiency (ARE) and the TW 80 retention efficiency (TW 80 RE), and the effects were in opposite directions. The biotoxicity of the SWE decreased as the experiment progressed, and at the end of the experiment, 30%-45% of TW 80 was still present in each set. And the oxidation group quenching experiments determined that the degradation of aniline was mainly contributed by active chlorine. Because active chlorine slowed the loss rate of TW 80, the electrochemical treatment of SWE + soil in-situ sequential batch recirculation washing method was designed, and 50% of aniline in the soil was washed out after 125h. At the end of the experiment, the less biotoxic SWE was collected where no aniline and TW 80 were present, and only small organic acids were present after the GC-MS test. The method has a great potential to be applied as it shows good results in the treatment of soil pollution incidents.

Auricular Acupressure for Hemodialysis Patients with Insomnia: A Multicenter Double-Blind Randomized Sham-Controlled Trial.

Background and objectives: The effect of auricular acupressure (AA) for maintenance hemodialysis (MHD) patients with insomnia has been controversial. This study assessed the efficacy and safety of AA for MHD patients with chronic insomnia. Design, setting, participants, and measurements: This was a multicenter, double-blind (participant and assessor), randomized sham-controlled trial. A total of 133 subjects were randomized to receive AA on active points (AA group, n = 64) or on sham auricular acupressure (SAA) points (SAA group, n = 69) for 8 weeks and followed up for 12 weeks. AA was provided by assigned qualified nurses who were not involved in assessment. The primary outcome was the clinical response rate, which was defined as the percentage of participants who reached a reduction of Pittsburgh Sleep Quality Index (PSQI) global score ≥3 in each group. Secondary outcomes included changes in PSQI scores over time, PSQI scores and hypnotics use at each visit, and changes in the weekly dose of hypnotics for drug-dependent subjects. Results: At week 8, the AA group yielded a higher clinical response rate than the SAA group (AA: 55% vs. SAA: 36%, odds ratio: 1.5, 95% confidence interval: 1.0-2.2, p = 0.033). Both groups showed a reduction in PSQI global scores during treatment and follow-up, compared with the baseline, respectively. A significant change of PSQI global score was observed over time (F = 28.387, p < 0.001). PSQI global score of the AA group was relatively lower than that of the SAA group at each visit (p < 0.05 at week 16 and 20). For those depending on hypnotics, AA reduced their consumption of hypnotics. The intervention was safe, and its adherence was satisfactory. Conclusion: AA could serve as a complementary or alternative therapy for MHD patients with insomnia by improving their sleep quality and reducing their use of hypnotics. Clinical trial registration: Clinicaltrials.gov, Identifier: NCT03015766.

Multi-cation hybrid stannic oxide electron transport layer for high-efficiency perovskite solar cells.

The performance of perovskite solar cells (PSCs) can be improved by optimizing the perovskite film quality and electron transfer layers (ETLs). In this study, high-efficient PSCs with multi-cation hybrid electron transport layer (SnO2@Na:Cs ETL) were fabricated using continuous spin-coating. Compared to the pristine SnO2, the power conversion efficiency (PCE) of device based on SnO2@Na:Cs ETL have reached 22.06% (with an open circuit voltage of 1.13 V), up approximately 21%. The photovoltaic performance of the device is enhanced due to the increase in the transmission rate, electrical conductivity, electron mobility and surface state owing to the multi-cation hybrid. In addition, because SnO2@Na:Cs ETL can significantly improve interface contact with the perovskite film and improve its crystallinity, the transport defect state and carrier transport efficiency are significantly improved at the ETL/Perovskite interface. Therefore, the open circuit voltage (Voc) and fill factor (FF) of PSCs was significantly increased. The application of SnO2@Na:Cs ETL provides a simple and efficient method to obtain highly-efficient PSCs.

Interface Regulation by an Ultrathin Wide-Bandgap Halide for Stable and Efficient Inverted Perovskite Solar Cells.

The nonradiative recombination between hole transport layers (HTLs) and perovskites generally leads to obvious energy losses. The trap states at the HTL/perovskite interface directly influence the improvement of the power conversion efficiency (PCE) and stability. Interface regulation is a simple and commonly used method to decrease nonradiative recombination in inverted perovskite solar cells (PSCs). Here, a wide-bandgap halide was used to regulate the PTAA/MAPbI3 interface, in which n-hexyltrimethylammonium bromide (HTAB) was used to modify the upper surface of poly[bis(4-phenyl)-(2,4,6-trimethylphenyl)amine] (PTAA). Upon introduction of the HTAB layer, the contact between PTAA and MAPbI3 is strengthened, the defect state density in PSCs is reduced, the MAPbI3 crystallinity is improved, and the nonradiative recombination loss is suppressed. The device with HTAB delivers the highest PCE of 21.01% with negligible hysteresis, which is significantly higher than that of the control device (17.71%), and it maintains approximately 87% of its initial PCE for 1000 h without encapsulation in air with a relative humidity of 25 ± 5%. This work reveals an effective way of using a wide-bandgap halide to regulate the PTAA/MAPbI3 interface to simultaneously promote the PCE and stability of PSCs.

High-efficiency planar heterojunction perovskite solar cell produced by using 4-morpholine ethane sulfonic acid sodium salt doped SnO2.

Perovskite solar cells (PSCs) have become a promising photovoltaic (PV) technology. Meanwhile, developing an electron transport layer (ETL) has been an effective way to promote the power conversion efficiency (PCE) of PSCs. Here, a 4-morpholine ethane sulfonic acid sodium salt (MES Na+) doped SnO2 ETL is utilized in planar heterojunction PSCs. The results show that the MES Na+ doped ETL can improve the crystallinity, and absorbance of perovskite films, and passivate interface defects between the perovskite film and SnO2 ETL. The doping effect accounts for the enhancement of conductivity and the decreasing work function of SnO2. When 10 mg mL-1 MES Na+ was added to the SnO2 precursor solution, the device showed the best performance Jsc, Voc, and FF of the PSCs values, which were 23.88 mA cm-2, 1.12 V and 78.69%, respectively, and the PCE was increased from 17.43% to 21.05%. This doping ETL strategy provides an avenue for defect passivation to further increase the efficiency of perovskite solar cells.

Late-onset Hearing Loss From Congenital Cytomegalovirus Infection After Newborn Period in a Highly Immune Population in China.

After following 141 children with likely asymptomatic congenital cytomegalovirus infection in a highly immune population in China, four children (2.8%) were found to have late-onset hearing loss. No maternal or childhood factors, except higher saliva cytomegalovirus viral load at birth (P = 0.03), were associated with increased risk of developing a hearing loss.

Dielectrophoresis Separation of Platelets Using a Novel Zigzag Microchannel.

Platelet separation and purification are required in many applications including in the detection and treatment of hemorrhagic and thrombotic diseases, in addition to transfusions and in medical research. In this study, platelet separation was evaluated using a novel zigzag microchannel fluidic device while leveraging a dielectrophoresis (DEP) electric field using the COMSOL multiphysics software package and additional experimentation. The zigzag-shaped microchannel was superior to straight channel devices for cell separation because the sharp corners reduced the required horizontal distance needed for separation and also contributed to an asymmetric DEP electric field. A perfect linear relationship was observed between the separation distance and the corner angles. A quadratic relationship (R2 = 0.99) was observed between the driving voltage and the width and the lengths of the channel, allowing for optimization of these properties. In addition, the voltage was inversely proportional to the channel width and proportional to the channel length. An optimal velocity ratio of 1:4 was identified for the velocities of the two device inlets. The proposed device was fabricated using laser engraving and lithography with optimized structures including a 0.5 mm channel width, a 120° corner angle, a 0.3 mm channel depth, and a 17 mm channel length. A separation efficiency of 99.4% was achieved using a voltage of 20 V and a velocity ratio of 1:4. The easy fabrication, lower required voltage, label-free detection, high efficiency, and environmental friendliness of this device make it suitable for point-of-care medicine and biological applications. Moreover, it can be used for the separation of other types of compounds including lipids.

A hybrid electrically-and-piezoelectrically driven micromixer built on paper for microfluids mixing.

This study aims to explore the channel patterns and the characteristic parameters of the zigzag microchannel based on microfluidic paper-based analytical devices (µPADs), in which the mixing efficiency and speed can be greatly enhanced. Better mixing of the solutions was obtained by adding a simple directing electric field to the optimized structure of the zigzag microchannel on paper-based chips instead of the traditional complex devices. A higher mixing efficiency was reached when the direct-current (DC) power supply reached 20 V. Meanwhile, a piezoelectric transducer (PZT) driver was used in the mixing experiment with the paper-based zigzag microchannel. The results show that the mixing efficiency reached a maximum value when the input voltage and frequency were 30 V and 150 Hz, respectively. These paper-based devices meet the requirements of the biochemical analysis field because they are low cost, easy to operate, and have high efficiencies, giving them good prospects for future applications. Graphical Abstract.

Single network double cross-linker (SNDCL) hydrogels with excellent stretchability, self-recovery, adhesion strength, and conductivity for human motion monitoring.

Hydrogels, as a kind of soft materials, are good candidates for smart skin-like materials. A double network is usually fabricated to improve the mechanical properties of hydrogels, and involves two different kinds of networks. In this work, a novel strategy for preparing single network double cross-linker (SNDCL) hydrogels was proposed and the prepared hydrogels exhibited excellent mechanical properties, including stretchability, compressibility, self-recovery, adhesion, shape memory and mechanical strength. N,N'-Methylenebisacrylamide forms covalent bonds with the network, while citric acid can form multiple weak interactions due to the polycarboxylic structure. This improves the tensile properties (6564%) and compressive properties of the hydrogel, and the hydrogels also exhibit long-lasting self-adhesion ability on various substrates. In addition, the hydrogels with multiple properties can be used as flexible strain sensors, allowing the monitoring of body movements. The hydrogels can hopefully be used in wearable electronic sensor devices and for healthcare monitoring.

An integrated platform for fibrinogen quantification on a microfluidic paper-based analytical device.

Fibrinogen (FIB) plays a key role in blood coagulation and thrombosis and its concentration in blood can directly reflect health conditions, thus efficient detection of FIB would benefit the treatments of certain diseases such as liver and heart diseases. However, there is a lack of sensitive, simple, rapid and cheap FIB detection device currently, in lieu of expensive and sophisticated approaches in laboratories. Here, we propose a novel plasma separation and FIB detection platform based on a microfluidic paper-based analytical device (µPAD). It is the first time that dielectrophoretic (DEP) force is combined with capillary force on paper for plasma separation, and the separation efficiency of plasma reaches about 95%, ensuring reliable downstream FIB detection, for which we also propose a new method called the resistance-fibrinogen detection (RFD) method. It not only avoids the use of large-scale instruments for detection, but also possesses high precision and simplicity. The method is found to be reliable in FIB detection for various concentrations ranging from 127.0 to 508.0 mg dL-1. Moreover, the results obtained from the proposed µPAD show an excellent agreement (R2 = 0.9985) with those obtained from an automatic coagulation analyzer with natural human blood samples. Overall, the proposed platform provides a low-cost and reliable approach for FIB detection, especially for clinical use in resource-limited areas.

Auricular acupressure for insomnia in hemodialysis patients: study protocol for a randomized controlled trial.

BACKGROUND: Patients on maintenance hemodialysis (MHD) frequently complain of insomnia. Poor sleep quality impairs their quality of life and adversely affects long-term outcome. Previously we applied auricular acupressure therapy (AAT) for MHD patients with insomnia and yielded favorable results. AAT probably improves sleep quality by stimulating the vagus nerve and inhibiting sympathetic overactivity. However, the efficacy of AAT for insomnia in this population is still lacking. The proposed randomized controlled trial (RCT) will evaluate the efficacy and safety of AAT for improvement of sleep quality in MHD patients with insomnia. METHODS/DESIGN: The proposed study is a multi-center, double-blind (participants and assessors), parallel-group RCT. A total of 112 participants with insomnia will be recruited from six hemodialysis centers in Guangzhou, China, and randomly allocated in a 1:1 ratio to receive auricular acupressure on either active points (AA group) or control points (points irrelevant to insomnia management, SAA group). The treatment will last for 8 weeks prior to a follow-up period of 12 weeks. Evaluation by blinded assessors at baseline, at 8 weeks (end of treatment) as well as at 4-week, 8-week and 12-week follow-ups (after intervention) will include Pittsburgh Sleep Quality Index (PSQI) scores and average weekly dose of hypnotics. The primary endpoint is clinical response rate (percentage of participants who reach a reduction of PSQI global score ≥ 3 in each group) at 8 weeks from baseline. Secondary endpoints include the changes in PSQI scores over time from baseline, as well as the changes in weekly dose of hypnotics. DISCUSSION: This paper describes the rationale and design of a double-blind RCT that aims to determine the efficacy and safety of AAT for insomnia of hemodialysis patients. If successful, this project will provide evidence of the efficacy and safety of AAT for insomnia of hemodialysis patients. TRIAL REGISTRATION: ClinicalTrials.gov , Identifier: NCT03015766 . Registered on 22 December 2016.

Let-7 inhibits self-renewal of hepatocellular cancer stem-like cells through regulating the epithelial-mesenchymal transition and the Wnt signaling pathway.

BACKGROUND: Tumor suppressive let-7 miRNAs are universally down-regulated in human hepatocellular carcinoma (HCC) versus normal tissues; however, the roles and related molecular mechanisms of let-7 in HCC stem cells are poorly understood. METHODS: We examined the inhibitory effect of let-7 miRNAs on the proliferation of MHCC97-H and HCCLM3 hepatic cancer cells by using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, which was further confirmed by apoptosis and cell cycle studies. The sphere-forming assay was used to study the effects of let-7a on stem like cells. Through western blot, immunofluorescence and the luciferase-reporter assay, we explored the activity of epithelial-mesenchymal transition (EMT) signaling factors in HCC cells. qRT-PCR was applied to detect miRNA expression levels in clinical tissues. RESULTS: Let-7a effectively repressed cell proliferation and viability, and in stem-like cells, also let-7a decreased the efficiency of sphere formation.in stem-like cells. The suppression of EMT signaling factors in HCC cells contributed to let-7's induced tumor viability repression and Wnt activation repression. Besides, Wnt1 is critical and essential for let-7a functions, and the rescue with recombinant Wnt1 agent abolished the suppressive roles of let-7a on hepatospheres. In clinical HCC and normal tissues, let-7a expression was inversely correlated with Wnt1 expression. CONCLUSIONS: Let-7 miRNAs, especially let-7a, will be a promising therapeutic strategy in the treatment of HCC through eliminating HCC stem cells, which could be achieved by their inhibitory effect on the Wnt signaling pathway.

Synthesis and immobilization of micro-scale drug particles in presence of ß-cyclodextrins.

The anti-solvent synthesis in presence of cyclodextrins (CDs) of the drug Griseofulvin (GF) is presented. This was followed by immobilization into cellulosic polymer films suitable for drug delivery. The results show that 72% of the GF precipitated in presence of CD, while the rest led to the formation of a water soluble GF/CD complex. The cyclodextrins were effective in inhibiting particle growth and stabilizing the drug suspensions. Among the CDs tested here, hydroxypropyl-ß-cyclodextrin (HPBCD) was found to be most effective in reducing the particle size. The release profiles from the cyclodextrin stabilized GF particles showed improvement in release rate, which indicated effective drug/cyclodextrin interactions.

Synthesis and immobilization of micro-scale drug particles in cellulosic films.

The anti-solvent synthesis of micron-scale particles, their stabilization, and subsequent self-assembly into polymer films suitable for drug delivery is presented. The colloidal particles were stabilized using low molecular weight hydroxypropyl methylcellulose (HPMC), while drug encapsulation was carried out with high molecular weight HPMC and polyvinylpyrrolidone (PVP). Griseofulvin (GF) was used as the model drug compound, and the polymer films were evaluated in terms of their surface morphology, mechanical properties and in vitro drug release. In general, the release rates were best described by first-order and Hixson-Crowell kinetic models, and in a typical film containing 57% HPMC, 100% of GF was released within 50 min.