Rational design of high performance conjugated polymers for organic solar cells

The research on the polymer based solar cells (PSCs) has attracted increasing amount of attention in recent years and great progresses have been made in the field of bulk heterojunction (BHJ) polymer solar cells since its inception in 1995. The power conversion efficiency (PCE) has increased from 1% in the 1990s to over 9% just recently. These great advances are mainly fueled by the development of conjugated polymers used as the electron-donating materials in BHJ solar cells. My research was focused on the rational design of those conjugated polymers. And first we investigated the positioning effect of alkyl side chains on the properties of conjugated polymers and find the best attaching position where high molecular weight and good solubility of conjugated polymers can be achieved without introducing large steric hindrance. Then, we proposed and demonstrated a weak donor-strong acceptor designing strategy to construct donor-acceptor type polymers with controlled energy levels. With those strategy to increase molecular weight, solubility and to control energy levels, we designed and synthesized several weak donor based conjugated polymers with solubilizing chains. Those polymers exhibited low HOMO levels, good solubility and molecular weight, thus high Voc and high PCE over 5% were obtained. Since most of the conjugated polymers developed so far have high-lying LUMO levels than desired LUMO, we developed some strong acceptor units to decrease the LUMO level of conjugated polymers. Combined with the methods we developed, conjugated polymers with high molecular weight, good solubility and near ideal energy levels were synthesized and they exhibit excellent PCE over 6%. In addition, by introducing fluorine atoms into conjugated backbone, we successfully created polymers with both low-lying HOMO and LUMO levels. Although band gap of this polymer is not ideal, large short circuit current (Jsc), open circuit voltage (Voc) and fill factor (FF) can still be obtained. Amazing PCE over 7% was demonstrated, which is among the best performances for polymer solar cells

An investigation of siloxane cross-linked hydroxyapatite–gelatin/copolymer composites for potential orthopedic applications

Causes of bone deficiency are numerous, but biomimetic alloplastic grafts provide an alternative to repair tissue naturally. Previously, a hydroxyapatite-gelatin modified siloxane (HAp-Gemosil) composite was prepared by cross-linking (N, N′-bis[(3-trimethoxysilyl)propyl]ethylene diamine (enTMOS) around the HAp-Gel nanocomposite particles, to mimic the natural composition and properties of bone. However, the tensile strength remained too low for many orthopedic applications. It was hypothesized that incorporating a polymer chain into the composite could help improve long range interaction. Furthermore, designing this polymer to interact with the enTMOS siloxane cross-linked matrix would provide improved adhesion between the polymer and the ceramic composite, and improve mechanical properties. To this end, copolymers of L-Lactide (LLA), and a novel alkyne derivatized trimethylene carbonate, propargyl carbonate (PC), were synthesized. Incorporation of PC during copolymerization affects properties of copolymers such as molecular weight, Tg, and % PC incorporation. More importantly, PC monomers bear a synthetic handle, allowing copolymers to undergo post-polymerization functionalization with graft monomers to specifically tailor the properties of the final composite. For our investigation, P(LLA-co-PC) copolymers were functionalized by an azido-silane (AS) via copper catalyzed azide-alkyne cycloaddition (CuAAC) through terminal alkyne on PC monomers. The new functionalized polymer, P(LLA-co-PC)(AS) was blended with HAp-Gemosil, with the azido-silane linking the copolymer to the silsesquioxane matrix within the final composite

Genetic diversity of three consecutive selective breeding generations in Pseudobagrus vachellii (Actinopterygii: Siluriformes: Bagridae)

Pseudobagrus vachellii (Richardson, 1846) is a commercially important freshwater fish species in China. To understand the effects of artificial breeding on the genetic diversity of three consecutive P. vachellii breeding populations (F1, F2, and F3) since 2012, a genetic analysis was conducted using polymorphic microsatellite markers. The mean allele number, expected heterozygosity, observed heterozygosity, and the polymorphic information content from generation F1 to F3 decreased from 7.75 to 5.63, from 0.77 to 0.63, from 0.83 to 0.77, and from 0.72 to 0.58, respectively. Analysis of molecular variance showed greater genetic divergence within the three generations (93.67%) than that among the generations (6.33%), and the overall differentiation level was moderate. Additionally, the lowest genetic differentiation was between F2 and F3 (Fst = 0.0484), and the highest was between F1 and F3 (Fst = 0.12864). Inbreeding occurred in each generation and was the highest in generation F3. Structural analysis showed that the three P. vachellii generations were most likely divided into two different genetic clusters. Although genetic diversity declined slightly in the mass selection lines after three breeding generations, overall genetic diversity was maintained at a relatively high level. To minimize the loss of genetic diversity and inbreeding in the subsequent breeding process, a moderate number of parents can be used for each generation. Information regarding the genetic diversity and structure of the selective P. vachellii breeding generations obtained in this study will be useful for future broodstock management and selective breeding programs

Genetic diversity of three consecutive selective breeding generations in Pseudobagrus vachellii (Actinopterygii: Siluriformes: Bagridae)

Pseudobagrus vachellii (Richardson, 1846) is a commercially important freshwater fish species in China. To understand the effects of artificial breeding on the genetic diversity of three consecutive P. vachellii breeding populations (F1, F2, and F3) since 2012, a genetic analysis was conducted using polymorphic microsatellite markers. The mean allele number, expected heterozygosity, observed heterozygosity, and the polymorphic information content from generation F1 to F3 decreased from 7.75 to 5.63, from 0.77 to 0.63, from 0.83 to 0.77, and from 0.72 to 0.58, respectively. Analysis of molecular variance showed greater genetic divergence within the three generations (93.67%) than that among the generations (6.33%), and the overall differentiation level was moderate. Additionally, the lowest genetic differentiation was between F2 and F3 (Fst = 0.0484), and the highest was between F1 and F3 (Fst = 0.12864). Inbreeding occurred in each generation and was the highest in generation F3. Structural analysis showed that the three P. vachellii generations were most likely divided into two different genetic clusters. Although genetic diversity declined slightly in the mass selection lines after three breeding generations, overall genetic diversity was maintained at a relatively high level. To minimize the loss of genetic diversity and inbreeding in the subsequent breeding process, a moderate number of parents can be used for each generation. Information regarding the genetic diversity and structure of the selective P. vachellii breeding generations obtained in this study will be useful for future broodstock management and selective breeding programs

Lenvatinib as First-Line Treatment for Unresectable Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

Lenvatinib was approved in 2018 as a first-line treatment for patients with unresectable hepatocellular carcinoma (HCC). This systematic review and meta-analysis aimed to provide the most updated evidence about the efficacy and safety of lenvatinib as a first-line treatment for unresectable HCC. An electronic search of the PubMed database, Web of Science, Embase, and Cochrane Library was undertaken to identify all relevant studies up to May 2022. The pooled effect sizes were calculated based on the random-effects model. One phase III randomized controlled trial and 23 retrospective studies of 2438 patients were eligible for analysis. For patients treated with lenvatinib as first-line treatment, the pooled median overall survival (OS), median progression-free survival (PFS), 1-year OS rate, 1-year PFS rate, objective response rate (ORR), and disease control rate (DCR) were 11.36 months, 6.68 months, 56.0%, 27.0%, 36.0% and 75.0%, respectively. Lenvatinib showed a significantly superior efficacy compared with sorafenib (HR for OS, 0.85 and HR for PFS, 0.72; OR for ORR, 4.25 and OR for DCR, 2.23). The current study demonstrates that lenvatinib can provide better tumor responses and survival benefits than sorafenib as a first-line treatment for unresectable HCC, with a comparable incidence of adverse events

Relationship between Soil Characteristics and Stand Structure of Robinia pseudoacacia L. and Pinus tabulaeformis Carr. Mixed Plantations in the Caijiachuan Watershed: An Application of Structural Equation Modeling

In order to study the multi-factor coupling relationships between typical Robinia pseudoacacia L. and Pinus tabulaeformis Carr. mixed plantations in the Caijiachuan basin of the Loess Plateau of Shanxi Province, West China, 136 sample plots were selected for building a structural equation model (SEM) of three potential variables: terrain, stand structure, and soil characteristics. Additionally, the indicators (also known as observed variables) were studied in this paper, including slope, altitude, diameter at breast height (DBH), tree height (TH), tree crown area, canopy density, stand density, leaf area index (LAI), soil moisture content, soil maximum water holding capacity (WHC), soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), ammonia-nitrogen (NH3-N), nitrate-nitrogen (NO3-N), and available phosphorus (AP). The results showed that terrain was the most important factor influencing soil moisture and nutrients, with a total impact coefficient of 1.303 and a direct path coefficient of 0.03, which represented mainly positive impacts; while correspondingly stand structure had a smaller negative impact on soil characteristics, with a total impact coefficient of −0.585 and a direct path coefficient of −0.01. The terrain also had a positive impact on the stand structure, with a total impact coefficient of 0.487 and a direct path coefficient of 0.63, indicating that the topography factors were more suitable for site conditions and both the stand structure and the soil moisture and nutrient conditions were relatively superior. By affecting the stand structure, terrain could restrict some soil, water, and nutrient functions of soil and water conservation. The influence coefficients of the four observed variables of DBH, stand density, soil water content, and organic matter, and potential variable topography reached 0.686, −0.119, 1.117, and 0.732, respectively; and the influence coefficients of soil moisture, organic matter and stand structure were −0.502 and −0.329, respectively. Therefore, besides observing the corresponding latent variables, the observed variables had a considerable indirect influence on other related latent variables. These relationships showed that the measures, such as changing micro-topography and adjusting stand density, should effectively maintain or enhance soil moisture and nutrient content so as to achieve improved soil and water conservation benefits in the ecologically important Loess Area

A new species of Kaloula (Amphibia: Anura: Microhylidae) from southern Guangxi, China

Mo, Yunming, Zhang, Wei, Zhou, Shichu, Chen, Tianbo, Tang, Huaxing, Meng, Yuanjun, Chen, Weicai (2013): A new species of Kaloula (Amphibia: Anura: Microhylidae) from southern Guangxi, China. Zootaxa 3710 (2): 165-178, DOI: 10.11646/zootaxa.3710.2.