解一类结构变分不等式问题的非精确并行交替方向法

带线性约束的具有两分块结构的单调变分不等式问题, 出现在许多现代应用中, 如交通和经济问题等. 基于该问题良好的可分结构, 分裂型算法被广泛研究用于其求解. 提出新的带回代的非精确并行交替方向法解该类问题, 在每一步迭代中,首先以并行模式通过投影得到预测点, 然后对其校正得到下一步的迭代点. 在压缩型算法的理论框架下, 在适当条件下证明了所提算法的全局收敛性. 数值结果表明了算法的有效性. 此外, 该算法可推广到求解具有多分块结构的问题.     

Green Electrospun Silk Fibroin Nanofibers Loaded with Cationic Ethosomes for Transdermal Drug Delivery

Transdermal drug delivery system(TDDS) facilitates the controlled release of active ingredients penetrating through the skin, avoiding the liver first pass effect. Electrospinning is a simple process to fabricate ultrafine fibers with a higher specific surface area, making them excellent candidates for drug delivery. In current work, a novel silk fibroin(SF) nanofiber loaded with cationic ethosomes(CEs) was prepared via green electrospinning. The data of Fourier transform infrared spectroscopy(FTIR) and laser scanning confocal microscopy(LSCM) confirmed the existence of CEs in the SF nanofibers. The morphology of the nanofibers was not significantly affected by the incorporation of CEs as shown by scanning electron microscopy(SEM) images. The CEs-loaded SF nanofibrous patch (CEs-SFnP) showed good cytocompatibility as proved by both cell counting Kit-8(CCK-8) assay and SEM. Using doxorubicin hydrochloride(Dox) as a model drug, the transdermal performance of CEs-SFnP was evaluated through Franz diffusion cell against mouse skin. The results indicated that CEs-SFnP can effectively deliver drug into the skin, with a much higher permeation rate than the normal nanofibers without CEs. The as-spun CEs-SFnP in this study could find promising applications in TDDS.     

两类求解y″＝f（x，y）具有极小相位延迟的显式方法

本文提出了两类数值积分二阶周期性初值问题ｙ″＝ｆ（ｘ，ｙ），ｙ（ｘ０）＝ｙ０，ｙ＇（ｘ０）＝ｙ＇０具有极小相位延迟的显式两步法。这些方法推广和改进了文献［１］－［７］中的某些方法。数值试验表明本文中的某些方法优于［１］－［７］中的某些方法。     

Electrochemical detection of indole alkaloids of Catharanthus roseus in high-performance liquid chromatography

Hydrodynamic voltammograms for indole and five indole alkaloids with different amino functions were obtained in order to evaluate the applicability of high-performance liquid chromatography (HPLC) with coulometric detection to these compounds. With the exception of serpentine, which has a quaternary nitrogen in its structure, all the compounds were oxidised and gave net signals of greater than 25 nA pmol(-1) at potentials of between +0.2 and +0.85 V versus a solid Pd electrode in an acetate-buffered (pH 6.5) water-methanol-acetonitrile system. An HPLC assay for quantifying picomole amounts of catharanthine and ajmalicine in Catharanthus roseus cell culture samples is described.     

Virial relations in density embedding

The accuracy of charge-transfer excitation energies, solvatochromic shifts, and other environmental effects calculated via various density-embedding techniques depend critically on the approximations employed for the nonadditive noninteracting kinetic energy functional, . Approximating this functional remains an important challenge in electronic-structure theory. To assist in the development and testing of approximations for , we derive two virial relations for fragments in molecules. These establish separate connections between the nonadditive kinetic energies of the noninteracting and interacting systems of electrons, and quantities such as the electron-nuclear attraction forces, the partition (or embedding) energy and potential, and the Kohn-Sham potentials of the system and its parts. We numerically verify both relations on diatomic molecules.     

Click and Release: A Chemical Strategy toward Developing Gasotransmitter Prodrugs by Using an Intramolecular Diels–Alder Reaction

Prodrug strategies have been proven to be a very effective way of addressing delivery problems. Much of the chemistry in prodrug development relies on the ability to mask an appropriate functional group, which can be removed under appropriate conditions. However, developing organic prodrugs of gasotransmitters represent unique challenges. This is especially true with carbon monoxide, which does not have an easy “handle” for bioreversible derivatization. By taking advantage of an intramolecular Diels–Alder reaction, we have developed a prodrug strategy for preparations of organic CO prodrugs that are stable during synthesis and storage, and yet readily release CO with tunable release rates under near physiological conditions. The effectiveness of the CO prodrug system in delivering a sufficient quantity of CO for possible therapeutic applications has been studied using a cell culture anti‐inflammatory assay and a colitis animal model. These studies fully demonstrate the proof of concept, and lay a strong foundation for further medicinal chemistry work in developing organic CO prodrugs.     

Highly Selective Catalytic Oxi-upcycling of Polyethylene to Aliphatic Dicarboxylic Acid under a Mild Hydrogen-Free Process

A low-temperature hydrogen-free process for upcycling polyethylene (PE) plastics into aliphatic dicarboxylic acid is developed using a heterogeneous catalyst Ru/TiO₂. The low-density PE (LDPE) conversion can reach 95 % in 24 h under a pressure of 1.5 MPa air at 160 °C with 85 % of the liquid product yield, which mainly is low molecular weight aliphatic dicarboxylic acid. Excellent performances can be also achieved for different PE feedstocks. This catalytic oxi-upcycling process paving a new way of upcycling polyethylene waste.     

A simple method to synthesize single-crystalline β-wollastonite nanowires

The single-crystalline β-wollastonite (β-CaSiO₃) nanowires were prepared via a simple hydrothermal method, in the absence of any template or surfactant using cheap and simple inorganic salts as raw materials. Xonotlite [Ca₆(Si₆O₁₇)(OH)₂] nanowires were first obtained after hydrothermal treatment at a lower temperature of 200 °C for 24 h, and after being calcinated at 800 °C for 2 h, xonotlite nanowires completely transformed into β-wollastonite nanowires and the wire-like structure was preserved. The synthesized β-wollastonite nanowires had a diameter of 10–30 nm, and a length up to tens of micrometers, and the single-crystalline monoclinic parawollastonite structured β-wollastonite was identified by XRD with the space group of P2₁/a and cell constants of a=15.42 Å, b=7.325 Å, c=7.069 Å and β=95.38°. A possible growth mechanism of β-wollastonite nanowires was also proposed. The advantages of this method for the nanowire synthesis lie in the high yield, low temperature and mild reaction conditions, which will allow large-scale production at low cost.     

Modifying the morphology via employing rigid phenyl side chains achieves efficient nonfullerene polymer solar cells

As a promising electron-deficient (acceptor) unit, fluorinated benzotriazole (TAZ) was used widely to construct wide bandgap polymers for nonfullerene polymer solar cells (NF-PSCs). However, due to the S…F noncovalent interaction, the unit show good planarity and strong aggregation, which was not beneficial for the blend with the elongated nonfullerene acceptors. Here, we tried to choose new donor polymers to match with TAZ unit, which was expected to destroy the interchain aggregation of polymer and form favorable morphology of blends. Two new wide-bandgap polymers PBDTsPhPh-T1 and PBDTsThPh-T1 based on the unsymmetrical benzodithiophene (BDT) units with a benzene ring as lever arms were synthesized. As a result, these two polymers blend well with nonfullerene acceptor (ITIC). And then, PBDTsPhPh-T1 and PBDTsThPh-T1-based devices exhibit the decent photovoltaic properties with high power conversion efficiencies of 8.85 and 9.34%, respectively. The work demonstrates that the unsymmetrical BDT units could be outstanding for building donor materials toward high-performance NF-PSCs. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2762–2770