In Situ Study the Dynamics of Blade-Coated All-Polymer Bulk Heterojunction Formation and Impact on Photovoltaic Performance of Solar Cells

All-polymer solar cells (all-PSCs) have achieved impressive progress by employing acceptors polymerized from well performing small-molecule non-fullerene acceptors. Herein, the device performance and morphology evolution in blade-coated all-PSCs based on PBDBT:PF5–Y5 blends prepared from two different solvents, chlorobenzene (CB), and ortho-xylene (o-XY) are studied. The absorption spectra in CB solution indicate more ordered conformation for PF5–Y5. The drying process of PBDBT:PF5–Y5 blends is monitored by in situ multifunctional spectroscopy and the final film morphology is characterized with ex situ techniques. Finer-mixed donor/acceptor nanostructures are obtained in CB-cast film than that in o-XY-cast ones, corresponding to more efficient charge generation in the solar cells. More importantly, the conformation of polymers in solution determines the overall film morphology and the device performance. The relatively more ordered structure in CB-cast films is beneficial for charge transport and reduced non-radiative energy loss. Therefore, to achieve high-performance all-PSCs with small energy loss, it is crucial to gain favorable aggregation in the initial stage in solution

In situ interface engineering for probing the limit of quantum dot photovoltaic devices.

Quantum dot (QD) photovoltaic devices are attractive for their low-cost synthesis, tunable band gap and potentially high power conversion efficiency (PCE). However, the experimentally achieved efficiency to date remains far from ideal. Here, we report an in-situ fabrication and investigation of single TiO2-nanowire/CdSe-QD heterojunction solar cell (QDHSC) using a custom-designed photoelectric transmission electron microscope (TEM) holder. A mobile counter electrode is used to precisely tune the interface area for in situ photoelectrical measurements, which reveals a strong interface area dependent PCE. Theoretical simulations show that the simplified single nanowire solar cell structure can minimize the interface area and associated charge scattering to enable an efficient charge collection. Additionally, the optical antenna effect of nanowire-based QDHSCs can further enhance the absorption and boost the PCE. This study establishes a robust 'nanolab' platform in a TEM for in situ photoelectrical studies and provides valuable insight into the interfacial effects in nanoscale solar cells

Etiologic Diagnosis of Lower Respiratory Tract Bacterial Infections Using Sputum Samples and Quantitative Loop-Mediated Isothermal Amplification

Etiologic diagnoses of lower respiratory tract infections (LRTI) have been relying primarily on bacterial cultures that often fail to return useful results in time. Although DNA-based assays are more sensitive than bacterial cultures in detecting pathogens, the molecular results are often inconsistent and challenged by doubts on false positives, such as those due to system- and environment-derived contaminations. Here we report a nationwide cohort study on 2986 suspected LRTI patients across P. R. China. We compared the performance of a DNA-based assay qLAMP (quantitative Loop-mediated isothermal AMPlification) with that of standard bacterial cultures in detecting a panel of eight common respiratory bacterial pathogens from sputum samples. Our qLAMP assay detects the panel of pathogens in 1047(69.28%) patients from 1533 qualified patients at the end. We found that the bacterial titer quantified based on qLAMP is a predictor of probability that the bacterium in the sample can be detected in culture assay. The relatedness of the two assays fits a logistic regression curve. We used a piecewise linear function to define breakpoints where latent pathogen abruptly change its competitive relationship with others in the panel. These breakpoints, where pathogens start to propagate abnormally, are used as cutoffs to eliminate the influence of contaminations from normal flora. With help of the cutoffs derived from statistical analysis, we are able to identify causative pathogens in 750 (48.92%) patients from qualified patients. In conclusion, qLAMP is a reliable method in quantifying bacterial titer. Despite the fact that there are always latent bacteria contaminated in sputum samples, we can identify causative pathogens based on cutoffs derived from statistical analysis of competitive relationship

Bone marrow-derived cells in ocular neovascularization: contribution and mechanisms

Ocular neovascularization often leads to severe vision loss. The role of bone marrow-derived cells (BMCs) in the development of ocular neovascularization, and its significance, is increasingly being recognized. In this review, we discuss their contribution and the potential mechanisms that mediate the effect of BMCs on the progression of ocular neovascularization. The sequence of events by which BMCs participate in ocular neovascularization can be roughly divided into four phases, i.e., mobilization, migration, adhesion and differentiation. This process is delicately regulated and liable to be affected by multiple factors. Cytokines such as vascular endothelial growth factor, granulocyte colony-stimulating factor and erythropoietin are involved in the mobilization of BMCs. Studies have also demonstrated a key role of cytokines such as stromal cell-derived factor-1, tumor necrosis factor-α, as well as vascular endothelial growth factor, in regulating the migration of BMCs. The adhesion of BMCs is mainly regulated by vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and vascular endothelial cadherin. However, the mechanisms regulating the differentiation of BMCs are largely unknown at present. In addition, BMCs secrete cytokines that interact with the microenvironment of ocular neovascularization; their contribution to ocular neovascularization, especially choroidal neovascularization, can be aggravated by several risk factors. An extensive regulatory network is thought to modulate the role of BMCs in the development of ocular neovascularization. A comprehensive understanding of the involved mechanisms will help in the development of novel therapeutic strategies related to BMCs. In this review, we have limited the discussion to the recent progress in this field, especially the research conducted at our laboratory

A Coordinative Method for Interruptible Loads Management in an Electricity Market

There are two compensation methods for interruptible loads (ILs), namely low price compensation before supply unavailability and high price compensation after supply unavailability. Low price compensation is independent of power supply unavailability, while the high compensation is performed only after actual power supply unavailability. However, the IL with low price (ILL) and the IL with high price compensation (ILH) have only been studied separately till now. Based on risk management, this paper analyzes the different economic properties of the two compensation methods and concludes that their coordination is beneficial to restrain market power and reduce the cost of reserve capacity. The authors propose the coordination models and optimization algorithms by taking the sum of the deterministic reduction of revenue resulting from ILL and the risk of compensating ILH as the objective function. Simulation results are presented to validate the effectiveness of the proposed method

Hybrid Optimization of System Adequacy Management in an Electricity Market

System adequacy has been recognized as one of the essential properties of a power market; however, there is no research work to date specifically on integrating demand-side management, demand-side reserve market and supply-side reserve market. To ensure system adequacy and improve the performance of reserve control, the time-of-use (TOU) power price can be employed as a preventive control. Dispatching the supply-side reserve, shedding interruptible loads with low and high price compensation in the demand-side reserve market are considered as emergency or corrective controls after a system event. Based on the different technical and economic properties of the emergency and preventive controls, this paper proposes to quantitatively analyze the performance of different control schemes using an integrated system model. An optimization algorithm is applied to individual emergency controls, preventive controls and the combination of these two controls. Simulation results are presented to validate the effectiveness of the proposed method

Energy Sources Part A-Recovery Util. Environ. Eff.

In this study, sorbent for flue gas desulfurization is prepared using metallurgical dusts (MD) abundant in iron oxides as the main active component, lime as promoter, and amylum as special additive. The reactivity of the sorbent is conducted in a quartz fixed-bed reactor within the medium temperature range of 300 degrees C-750 degrees C under heating and isothermal conditions, while the physical and chemical properties of the sorbent are measured using ICP-AAS, SEM, XRD, and so on. The experimental results indicate that with temperature increasing from 300 degrees C to 750 degrees C, breakthrough sulfur capacity of the sorbent increases from 0.0257 gS/gSorbent at 300 degrees C to 0.1391 gS/gSorbent at 650 degrees C, then decreases to 0.0836 gS/gSorbent at 750 degrees C, and that the removal efficiency of SO2 and breakthrough sulfur capacity of the sorbent depend on the chemical kinetics of Fe2O3 and CaO in the temperature range of lower than 600 degrees C, but on the thermodynamic equilibrium of sulfuration of Fe2O3, the thermal stability of the Fe-2(SO4)(3) and content of CaO in the range of higher than 650 degrees C. Physical and chemical analyses of the fresh and reacted sorents further verify that the effective and dominating component of the sorbent is Fe2O3 within the temperature range of lower than 650 degrees C, while is CaO in higher than 650 degrees C.In this study, sorbent for flue gas desulfurization is prepared using metallurgical dusts (MD) abundant in iron oxides as the main active component, lime as promoter, and amylum as special additive. The reactivity of the sorbent is conducted in a quartz fixed-bed reactor within the medium temperature range of 300 degrees C-750 degrees C under heating and isothermal conditions, while the physical and chemical properties of the sorbent are measured using ICP-AAS, SEM, XRD, and so on. The experimental results indicate that with temperature increasing from 300 degrees C to 750 degrees C, breakthrough sulfur capacity of the sorbent increases from 0.0257 gS/gSorbent at 300 degrees C to 0.1391 gS/gSorbent at 650 degrees C, then decreases to 0.0836 gS/gSorbent at 750 degrees C, and that the removal efficiency of SO2 and breakthrough sulfur capacity of the sorbent depend on the chemical kinetics of Fe2O3 and CaO in the temperature range of lower than 600 degrees C, but on the thermodynamic equilibrium of sulfuration of Fe2O3, the thermal stability of the Fe-2(SO4)(3) and content of CaO in the range of higher than 650 degrees C. Physical and chemical analyses of the fresh and reacted sorents further verify that the effective and dominating component of the sorbent is Fe2O3 within the temperature range of lower than 650 degrees C, while is CaO in higher than 650 degrees C

Protective effect of low molecular weight heparin on experimental colitis: role of neutrophil recruitment and TNF-alpha production.

OBJECTIVE: The purpose of this study was to examine the impact and mechanism of action of low molecular weight heparin (LMWH) in a model of murine colitis. MATERIALS AND METHODS: Balb/c mice were exposed to 5% dextran sodium sulfate (DSS) in the drinking water for five days. LMWH (500 units/kg/day) was administered by subcutaneous injection prior to and throughout the treatment period with DSS. Clinical disease activity index (DAI), including body weight loss, stool consistency and blood in feces were examined daily. Moreover, crypt height (CH), mucosal damage score (MDS), myeloperoxidase (MPO) activity and tumor necrosis factor-alpha (TNF-alpha) content in the colon were determined. RESULTS: DSS increased DAI, MDS, MPO activity and TNF-alpha production and decreased CH. Administration of LMWH markedly reduced DAI, MDS and reversed the CH-reduction. Moreover, in LMWH-treated animals, the MPO activity was reduced by more than 67% whereas mucosal levels of TNF-alpha was similar compared to DSS control mice. CONCLUSIONS: These findings suggest that LMWH inhibits murine colitis by interference with neutrophil recruitment and that LMWH may provide a novel pharmacological approach to treatment of inflammatory bowel disease