Photoregulation of Gene Expression with Ligand-Modified Caged siRNAs through Host/Guest Interaction

Small interfering RNA (siRNA) can effectively silence target genes through Argonate 2 (Ago2)-induced RNA interference (RNAi). It is very important to control siRNA activity in both spatial and temporal modes. Among different masking strategies, photocaging can be used to regulate gene expression through light irradiation with spatiotemporal and dose-dependent resolution. Many different caging strategies and caging groups have been reported for light-activated siRNA gene silencing. Herein, we describe a novel caging strategy that increases the blocking effect of RISC complex formation/process through host/guest (including ligand/receptor) interactions, thereby enhancing the inhibition of caged siRNA activity until light activation. This strategy can be used as a general approach to design caged siRNAs for the photomodulation of gene silencing of exogenous and endogenous genes.     

Host/guest complex of Me-β-CD/2,2-dimethoxy-2-phenyl acetophenone for initiation of aqueous photopolymerization: Kinetics and mechanism

Methylated-β-cyclodextrin (Me-β-CD) was used to complex the photoinitiator, 2,2-dimethoxy-2-phenyl acetophenone (DMPA), yielding a water-soluble host/guest complex. The comparative studies demonstrated that the Me-β-CD complexed DMPA exhibited a high photoreactivity identical to the uncomplexed DMPA, while the CD complex obviously influenced the products of primary photolysis of DMPA and the photopolymerization kinetics due to the steric effect of CD on the subsequent initiation reactions. The photopolymerization rate of acrylamide can be described by the equation: R_p=K[2a]^0.62[M]^1.37[I]^0.5[Me-β-CD]⁰. The mechanism of polymerization was also discussed.     

Femtochemistry of Guest Molecules Hosted in Colloidal Zeolites

The ultrafast deprotonation of 2‐(2′‐hydroxyphenyl)benzothiazole (HBT) hosted in nanometer‐sized FAU and MFI zeolites is reported. Samples are prepared via in‐situ incorporation of HBT in the precursor colloidal solutions resulting in the formation of nanometer‐sized zeolites under hydrothermal treatment. The diameter of the zeolite particles formed in the crystalline suspensions is determined by dynamic light scattering and high‐resolution transmission microscopy to lie in the range 40–100 nm. It is shown that the HBT loading does not influence the degree of the zeolite crystallinity but does change the size and the morphology of the individual zeolite nanoparticles. Colloidal suspensions containing the crystalline nanoparticles are well suited for optical investigations since they are sufficiently transparent and clear. The photochemical properties of the HBT guest in the zeolite‐host systems are studied with femtosecond transient transmission spectroscopy. Depending on the acid–base properties either the enol or the keto tautomer of HBT is found to be hosted in the internal voids of the zeolites; upon UV excitation, the HBT‐keto tautomer is converted to the enol form in both MFI‐ and FAU‐type hosts. The HBT photoconversion takes place via an ultrafast deprotonation within 1.5 ps as detected by femtosecond transient absorption spectroscopy.     

Humidity sensitivity of polypyrrole and polypyrrole/SBA‐15 host–guest composite materials

Polypyrrole (PPY) and PPY/SBA‐15 host–guest composite materials have been prepared using chemical synthesis route and characterized by XRD, IR, N₂ adsorption–desorption isotherms, and SEM. The humidity sensitive properties (HSP) of this kind of materials have been studied by analyzing the variation curve of impedance as a function of relative humidity. It was found that the PPY/SBA‐15 host–guest composites materials exhibit better HSP than that of the corresponding pure PPY. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3301–3305, 2006     

Encapsulation and controlled release in polyacrylamide hydrogels

A novel host–guest system was developed by the encapsulation of simple organic guest molecules in the hydrophilic molecular architecture of crosslinked polyacrylamide hydrogels. The crosslinking agents used for the preparation of the host systems were hexanediol dimethacrylate (HDDMA) and divinyl benzene (DVB). This enabled us to construct hydrogels with different hydrophobic–hydrophilic equilibria. The model guest system used for the studies was benzoic acid. The selections gave simple but excellent host–guest systems with fine polar–apolar balancing. Polyacrylamide hydrogels with encapsulated benzoic acid were prepared with varying crosslink densities (5, 10, 15, and 20 mol %) by the solution polymerization technique. The rate of release of the host from the host–guest assembly was studied in different swelling conditions. The rate of release depended on the interaction forces between the polymer and the solvents. Polar forces, dispersion forces, and hydrogen bonding all played a vital role. The swelling behavior of the host‐polymer system and the host–guest assembly was analyzed and compared by the Flory–Rehner method. The amount of benzoic acid encapsulated in the DVB‐crosslinked polymer was higher than in the HDDMA‐crosslinked polymer, and the rate of release was in the order 5 > 15 > 10 > 20% for the DVB‐crosslinked polymer. The rate of release for the HDDMA‐crosslinked host–guest assembly was in the order 10 > 5 > 15 > 20%. These results were in excellent agreement with those of the Flory–Rehner analysis of the swelling properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1816–1824, 2004     

环糊精及其包合物的研究与应用

介绍了环糊精及其包合物的合成、结构、包合物形成的热力学与动力学等的研究概况，着重叙述了环糊精的包合作用与环糊精的修饰，描绘了环糊精化学的应用与发展前景。     

19.28% Efficiency and Stable Polymer Solar Cells Enabled by Introducing an NIR-Absorbing Guest Acceptor

Here, a near-infrared (NIR)-absorbing small-molecule acceptor (SMA) Y-SeNF with strong intermolecular interaction and crystallinity is developed by combining selenophene-fused core with naphthalene-containing end-group, and then as a custom-tailor guest acceptor is incorporated into the binary PM6:L8-BO host system. Y-SeNF shows a 65 nm red-shifted absorption compared to L8-BO. Thanks to the strong crystallinity and intermolecular interaction of Y-SeNF, the morphology of PM6:L8-BO:Y-SeNF can be precisely regulated by introducing Y-SeNF, achieving improved charge-transporting and suppressed non-radiative energy loss. Consequently, ternary polymer solar cells (PSCs) offer an impressive device efficiency of 19.28% with both high photovoltage (0.873 V) and photocurrent (27.88 mA cm⁻²), which is one of the highest efficiencies in reported single-junction PSCs. Notably, ternary PSC has excellent stability under maximum-power-point tracking for even over 200 h, which is better than its parental binary devices. The study provides a novel strategy to construct NIR-absorbing SMA for efficient and stable PSCs toward practical applications.     

Application of CAN Bus in Hotel Guest Room Service and Management System

Technical features about CAN bus are described. One kind of scheme in Hotel Guest RoomService and Management System based on CAN bus is presented. The system's structure and mainfunction are expounded. The work principle and design of the system's hardware and software areexplained. The realization of the system's hardware and software is detailed from aspects of     

A novel polarizer‐free dye‐doped polymer‐dispersed liquid crystal for reflective TFT displays

Abstract— A novel preparation method for dichroic dye‐doped polymer‐dispersed liquid crystals has been developed. This was achieved by creating a porous polymer matrix first by washing out the liquid crystal from a polymer‐dispersed liquid crystal (PDLC), which is then refilled with dye‐doped liquid crystal. Optimizing the liquid crystal used in the refilling results in decreased turn‐on voltage and faster response time. Poster‐standard reflectivity and newspaper‐standard contrast was demonstrated with a 3.8‐in. QVGA reflective TFT display with a drive voltage of 10 V.