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Background/Aims: Matrix metalloproteinase 9 (MMP9), a potent endopeptidase degrading extracellular matrix, plays a pivotal role in the pathogenesis of ischaemic stroke (IS). The present study was undertaken to determine the association of MMP9 gene polymorphisms and the risk of IS in a southern Chinese population. Methods: A cohort of 1274 patients and 1258 age-matched healthy controls were genotyped to detect the four MMP9 polymorphisms (rs17156, rs3787268, rs3918241 and rs3918242) using SNaPshot. Results: Our study demonstrated a significant difference in the genotype and allele frequencies of the MMP9 rs3918242 polymorphism between the IS patients and the controls (P = 0.012 for the genotype and P = 0.0092 for the allele). Stratification by smoking status showed statistically significant differences in the frequency and allele of the rs3918242 polymorphism between IS patients and the controls (P = 0.0052 for the genotype and P = 0.0019 for the allele). Further stratification by IS subtypes revealed that the presence of the T allele of the MMP9 rs3918242 polymorphism confers a higher risk of the large artery atherosclerosis subtype of IS (P = 0.017). Moreover, IS patients with the rs3918242 T allele of MMP9 presented with increased serum MMP9 production, and this increase was more significant in smokers with IS (P = 0.022). Patients carrying the variant T allele of the MMP9 rs3918242 polymorphism exhibited significantly higher infarct volumes than those with the major CC genotype (P = 0.036). Conclusion: Our study provides preliminary evidence that the MMP9 rs3918242 polymorphism is linked to a higher risk of IS, confirming the role of MMP9 in the pathophysiology of IS, with potentially important therapeutic implications. [ABSTRACT FROM AUTHOR]

Abstract: Due to the attraction of optimizing the electronic structure beyond chemical synthesis, molecular doping has recently aroused wide interest in the field of organic solar cells. However, the selection of limited dopants confines its successful application. Inspired by the Lewis base characteristics of the photovoltaic materials, the Lewis acid as novel dopant is introduced in organic solar cells. In both fullerene and nonfullerene based blends, Lewis acid doping leads to increased photovoltaic performance. Detailed experiments reveal that Lewis acid doping has a synergistic effect on modifying the polymer's electronic properties and the acceptor's nanostructure even at low doping concentration, and these are simultaneously responsible for the device improvements. Based on the mechanism studies, it is proposed that the Lewis acid‐doped polymers anions produce induced dipole on the acceptor, this increases the intermolecular interaction and facilitates the morphology optimization. It is believed that the synergistic effect by Lewis acid doping greatly expands the application of doped organic solar cells, in concert with other existing methods to yield higher efficiency values. [ABSTRACT FROM AUTHOR]

A novel diketopyrrolopyrrole (DPP)-based conjugated polymer (PCDPP) was designed, synthesized and used as a donor material for polymer solar cells (PSCs). By increasing the planarity of polymer chains and reducing the energy loss in devices, we have simultaneously acquired a high short-circuit current (Jsc) and a large open-circuit voltage (Voc) in PSCs based on PCDPP, which is a regular alternating ternary conjugated polymer. This polymer has a medium optical band gap (1.55 eV) with low-lying HOMO and LUMO energy levels. In addition, PCDPP exhibits a very good planarity from density functional theory (DFT) calculations and forms a fibrillar network in the active layer of solar cells. Because of these integrated favourable effects, PCDPP-based photovoltaic devices exhibit a high power conversion efficiency (PCE) of 9.02% which is among the highest values reported so far for devices based on DPP-containing polymers. More importantly, the Voc of our PCDPP-based devices can reach as high as 0.86 V, which is much higher than that (＜0.7 V) of high-efficiency solar cells based on other DPP polymers. These results provide a promising way to minimize the energy loss and to realize high Voc and Jsc values at the same time in devices to obtain high power conversion efficiencies. [ABSTRACT FROM AUTHOR]

The power conversion efficiency of polymer solar cells (PSCs) is strongly affected by active layer morphology. Here, two solvent additives (ODT: octance‐1,8‐dithiol; DIO: 1,8‐diiodooctane) are used to optimize the bulk heterojunction morphology of FTAZ:ITIC‐Th based PSCs and ≈11% efficiency is obtained, which is 10% higher than the untreated device. Based on the morphological characterizations, the influence of binary solvent additives on manipulating molecular packing and phase separation of blend films is successfully revealed. More importantly, in situ grazing incidence wide‐angle X‐ray scattering characterization is adopted to explore the crucial role played by these two solvent additives at different stages of the film‐forming process, that is, ODT influences the initial stage of the film‐forming process, while DIO later establishes the ultimate photoactive film formation. Due to the impacts of two additives at different film processing stages, an optimal ratio of ODT:DIO (0.375%:0.125%) is obtained, which helps in realizing the optimized morphology. The device with binary additive of octance‐1,8‐dithiol:1,8‐diiodooctane (ODT:DIO) (0.375%:0.125%) based on FTAZ:ITIC‐Th blends exhibits a higher power conversion efficiency of 10.93% than the devices processed with only 0.5% ODT, 0.5% DIO, or excess binary additive of ODT:DIO (0.5%:0.5%). The reason is that additives with different boiling point work in different stages during the whole filming process as in situ grazing incidence wide‐angle X‐ray scattering characterization indicates. [ABSTRACT FROM AUTHOR]

To explore the influence of fluoro substitution position and number on optical, electrochemical and photovoltaic properties, three novel donor-acceptor (D-A) alternative copolymers ( PHF , PFH and PFF ) were synthesized by Stille polycondensation of 2,3-diphenyl-5,8-di(thiophen-2-yl)quinoxaline (DTQx) acceptor unit and indacenodithiophene (IDT) donor unit. As films, PHF and PFF comprising two fluoro substituents on the lateral phenyl groups displayed a broad absorption ranging from 350 to 700 nm; whereas PFH containing two fluorine atoms on the polymer main chain exhibited a slightly narrower absorption ranging from 350 to 650 nm. In addition, fluoro substitution on the polymer main chain can lower the HOMO level of the resulted polymers. As expected, PFH and PFF possess deeper HOMO energy level than PHF . Polymer solar cells (PSCs) were fabricated with these three polymers as donor materials and PC 71 BM as acceptor material. PHF based PSCs gave a power conversion efficiency (PCE) of 7.2% with a V oc of 0.84 V, a J sc of 12.46 mA/cm 2 and an FF of 0.69. And PFH based PSCs showed a PCE of 6.19% with a V oc of 0.93 V, a J sc of 9.57 mA/cm 2 and an FF 0.70. However, a PCE of only 2.9% with a V oc of 0.92 V, a J sc of 4.61 mA/cm 2 and an FF of 0.68 was obtained for PFF based PSCs. Transmission electron microscopy (TEM) and resonant soft X-ray scattering (R-SoXS) studies indicated that the introduction of four fluorine atoms at each repeating unit can spoil the morphology of active layer. These results highlight the importance of fluorination position and number to the performance of PSCs. [ABSTRACT FROM AUTHOR]