Transition Metal Chalcogenides/Nonconjugated Polymer Artificial Photosystems for Photoredox Catalysis.

Surface charge transfer doping (SCTD) has been established as an efficient strategy to achieve strong electronic coupling interactions between semiconductors and dopants, which lead to highly efficient electron transport over semiconductors. Herein, we report a facile, easily accessible, and effective SCTD strategy to exquisitely modulate the interfacial charge transfer over transition metal chalcogenides (TMCs: CdS, ZnCdS, CdInS, and ZnInS) through surface modification with a nonconjugated polymer, poly(dimethyldiallylammonium chloride) (PDDA). We provide evidence that PDDA, as a surface electron transfer acceptor, can be used to enable rapid, directional, and tunable charge transfer along with an optimal charge lifetime over TMCs in photoredox catalysis because of the high-efficiency electron-trapping property of quaternary ammonium functional groups in the molecular structure of PDDA.

Low viscosity and low temperature curing reactive POSS/epoxy hybrid resin with enhanced toughness and comprehensive thermal performance.

The mechanical and high-temperature resistance properties of epoxy resins cured at low temperatures ( ≤ 100 °C) are often inferior, and the most toughening modification methods for epoxy resins tend to compromise thermal resistance, which significantly limit the practical applications of it. Therefore, this work reported a low viscosity and low-temperature curing epoxy hybrid resin system (OPEP), adopting E-51 as a resin matrix, liquid anhydride (MHHPA) as a curing agent, tertiary amine (DMBA) as a curing accelerator, and reactive octa-epoxy terminated polyhedral oligomeric silsesquioxane (OG-POSS) as a toughening modifier. Results demonstrated that the OPEP system has excellent processability with low viscosity and long processing window period and satisfies the practical requirements of low-temperature curing.

Polypeptides inhibit HIV-1 replication by interfering viral Vpu-mediated tetherin degradation.

Background: HIV-1 Vpu acts by counteracting the tethering function of tetherin and resulting in the release of HIV-1 virion. Disrupting Vpu-tetherin interactions may provide a promising new target for antiretroviral therapy.

Methods: Polypeptides that covered the amino acid sequence on the interface of Vpu-tetherin complex were designed.

Compact and high Q-factor multimode racetrack ring resonator based on transformation optics.

The ring resonator is a versatile and functional component in the silicon-based integrated optical circuit. Most of the previously reported ring resonators work in the single-mode case. With the rapid development of mode division multiplexing technology, a multimode ring resonator (MMRR) has been proposed and the usage beyond the limit of a conventional single mode ring resonator has been explored.

Structural control of a novel hierarchical porous carbon material and its adsorption properties.

Novel hierarchical porous carbon materials (HPCs) were fabricated via a reactive template-induced in situ hypercrosslinking procedure. The effects of carbonization conditions on the microstructure and morphology of HPCs were investigated, and the adsorption of methylene blue (MB) on HPCs was explored. The as-prepared HPCs has a hierarchical micro-, meso- and macropore structure, which results from the overlap of hollow nanospheres possessing microporous shells and macroporous cavities.

Deterministic design of focusing apodized subwavelength grating coupler based on weak form and transformation optics.

The focusing apodized subwavelength grating coupler (F-ASGC) has advantages of high coupling efficiency, small footprint and simple fabrication process, which make it a popular component for chip-scale coupling and testing of integrated optical circuit. However, the design of F-ASGC based on effective medium theory lacks accuracy, causing the drawbacks of peak wavelength deviation and performance degradation. In this work, we propose a deterministic design method of F-ASGC.

Characterization of the complete mitochondrial genome of s, the endemic Lepus in China.

s is the endemic species in China and has been listed on the IUCN Red List in 2013. In this study, we undertook and obtained the complete s mitochondrial genome. The circular mitochondrial genome sequence is 17,534 bp in size, containing 13 protein-coding genes (PCGs), 21 transfer RNA (tRNA) genes, 2 ribosome RNA (rRNA) genes and a longer D-loop region of 2,610 bp in length.

CASC2/miR-24/miR-221 modulates the TRAIL resistance of hepatocellular carcinoma cell through caspase-8/caspase-3.

Hepatocellular carcinoma is one of the most common solid tumors in the digestive system. The prognosis of patients with hepatocellular carcinoma is still poor due to the acquisition of multi-drug resistance. TNF Related Apoptosis Inducing Ligand (TRAIL), an attractive anticancer agent, exerts its effect of selectively inducing apoptosis in tumor cells through death receptors and the formation of the downstream death-inducing signaling complex, which activates apical caspases 3/8 and leads to apoptosis.

A novel bispecific peptide HIV-1 fusion inhibitor targeting the N-terminal heptad repeat and fusion peptide domains in gp41.

HIV-1 fusion with the target cell is initiated by the insertion of the gp41 fusion peptide (FP) into the target cell membrane and the interaction between the gp41 N- and C-terminal heptad repeats (NHR and CHR), followed by the formation of the six-helix bundle (6-HB) fusion core. Therefore, both FP and NHR are important targets for HIV-1 fusion inhibitors. Here, we designed and synthesized a dual-target peptidic HIV-1 fusion inhibitor, 4HR-LBD-VIRIP, in which 4HR-LBD is able to bind to the gp41 NHR domain, while VIRIP is able to interact with gp41 FP.

Strong contribution of pore morphology to the high-rate electrochemical performance of lithium-ion batteries.

The interconnected ordered pore channels facilitate faster permeation of Li(+) ions during the charge-discharge process than the isolated ordered pore channels, resulting in significantly enhanced capacities, better rate capabilities and more remarkable cycling stability.

Silica nanonetwork confined in nitrogen-doped ordered mesoporous carbon framework for high-performance lithium-ion battery anodes.

A new class of nitrogen-doped ordered mesoporous carbon/silica (N-OMC/SiO2) nanocomposites was successfully fabricated via a multi-constituent co-assembly strategy. The N-OMC/SiO2 nanocomposite presented a unique interpenetrating carbon/silica structure whose carbon/silica interface is highly uniform, and thus demonstrated high capacity, good cycling and excellent rate properties.

Conjugation of a nonspecific antiviral sapogenin with a specific HIV fusion inhibitor: a promising strategy for discovering new antiviral therapeutics.

Triterpene saponins are a major group of active components in natural products with nonspecific antiviral activities, while T20 peptide (enfuvirtide), which contains a helix zone-binding domain (HBD), is a gp41-specific HIV-1 fusion inhibitor. In this paper, we report the design, synthesis, and structure-activity relationship (SAR) of a group of hybrid molecules in which bioactive triterpene sapogenins were covalently attached to the HBD-containing peptides via click chemistry. We found that either the triterpenes or peptide part alone showed weak activity against HIV-1 Env-mediated cell-cell fusion, while the hybrids generated a strong cooperative effect.

The use of hairpin DNA duplexes as HIV-1 fusion inhibitors: synthesis, characterization, and activity evaluation.

Discovery of new drugs for the treatment of AIDS that possess unique structures associated with novel mechanisms of action are of great importance due the rapidity with which drug-resistant HIV-1 strains evolve. Recently we reported on a novel class of DNA duplex-based HIV-1 fusion inhibitors modified with hydrophobic groups. The present study describes a new category of hairpin fusion inhibitor DNA duplexes bearing a 3 nucleotide loop located at either the hydrophobic or hydrophilic end.

Hydrophobic mutations in buried polar residues enhance HIV-1 gp41 N-terminal heptad repeat-C-terminal heptad repeat interactions and C-peptides' anti-HIV activity.

Objective: To investigate the effect of mutations in a highly conserved buried polar area on the function of HIV-1 gp41.

Design: During HIV-1 entry, a six helical bundle (6-HB) formation between the C-terminal and N-terminal heptad repeat (CHR and NHR) of gp41 provides energy for virus cell membrane fusion. In 6-HB, residues at a and d (a-d) positions of CHR directly interact with NHR and are buried.

Artificial peptides conjugated with cholesterol and pocket-specific small molecules potently inhibit infection by laboratory-adapted and primary HIV-1 isolates and enfuvirtide-resistant HIV-1 strains.

Objectives: To develop new HIV-1 fusion inhibitors with improved antiviral activities and resistance profiles, we designed two categories of artificial peptides, each containing four heptad repeats (m4HR) conjugated with a pocket-specific small molecule (pssm) or pssm and cholesterol (chol), designated pssm-m4HR or pssm-m4HR-chol, respectively, and tested their anti-HIV-1 activity.

Methods: We synthesized the artificial peptides and conjugated these peptides with pssm and chol using a standard solid-phase Fmoc protocol and a chemoselective thioether conjugation method, respectively. We tested the inhibitory activities of the peptide conjugates against HIV-1 Env-mediated cell-cell fusion and infection by laboratory-adapted and primary HIV-1 isolates, and enfuvirtide-resistant HIV-1 strains using cell-cell fusion and p24 production assays, respectively.

Exchangeability of amino acid residues with similar physicochemical properties in coiled-coil interactions.

Systematic exchange of amino acid residues of similar physicochemical properties maintains specific coiled-coil interaction between two heptad repeats of HIV-1 gp41, as well as the biological activity of related peptide fusion inhibitors. This exchangeability can greatly degenerate sequence space of peptides thus making ab initio design of coiled-coil interaction feasible.

Increase of anti-HIV activity of C-peptide fusion inhibitors using a bivalent drug design approach.

We reported the design of fusion inhibitors with improved activity using a multivalent inhibitor design strategy. First, we chose C29 as the template sequence, which is a 29-mer peptide derived from HIV-1 gp41 CHR domain and has anti-HIV activity of IC50 118 nM in a cell-cell fusion assay. We optimized the crosslink sites and linkers of the template peptide.

DNA duplexes with hydrophobic modifications inhibit fusion between HIV-1 and cell membranes.

Discovery of new drugs for the treatment of AIDS typically possessing unique structures associated with novel mechanisms of action has been of great importance due to the quick drug-resistant mutations of HIV-1 strains. The work presented in this report describes a novel class of DNA duplex-based HIV-1 fusion inhibitors. Hydrophobic groups were introduced into a DNA duplex skeleton either at one end, at both ends, or in the middle.

Design, synthesis, and biological evaluation of highly potent small molecule-peptide conjugates as new HIV-1 fusion inhibitors.

The small molecule fusion inhibitors N-(4-carboxy-3-hydroxyphenyl)-2,5-dimethylpyrrole (NB-2) and N-(3-carboxy-4-hydroxyphenyl)-2,5-dimethylpyrrole (A12) target a hydrophobic pocket of HIV-1 gp41 and have moderate anti-HIV-1 activity. In this paper, we report the design, synthesis, and structure-activity relationship of a group of hybrid molecules in which the pocket-binding domain segment of the C34 peptide was replaced with NB-2 and A12 derivatives. In addition, the synergistic effect between the small molecule and peptide moieties was analyzed, and lead compounds with a novel scaffold were discovered.

Design of highly potent HIV fusion inhibitors based on artificial peptide sequences.

Specific interactions were introduced between an artificial heptad repeat peptide template and HIV-1 gp41 for fusion inhibitor design, using a structure based rational design strategy. The designed peptides are nonhomologous with naturally occurring peptide and protein sequences, specifically interact with HIV-1 gp41, and show strong anti-HIV activity.

Covalent fusion inhibitors targeting HIV-1 gp41 deep pocket.

Covalent inhibitors form covalent adducts with their target, thus permanently inhibiting a physiological process. Peptide fusion inhibitors, such as T20 (Fuzeon, enfuvirtide) and C34, interact with the N-terminal heptad repeat of human immunodeficiency virus type 1 (HIV-1) gp41 glycoprotein to form an inactive hetero six-helix bundle (6-HB) to prevent HIV-1 infection of host cells. A covalent strategy was applied to peptide fusion inhibitor design by introducing a thioester group into C34-like peptide.

A multi-functional peptide as an HIV-1 entry inhibitor based on self-concentration, recognition, and covalent attachment.

HIV entry is mediated by the envelope glycoproteins gp120 and gp41. The gp41 subunit contains several functional domains: the N-terminal heptad repeat (NHR) domains fold a triple stranded coiled-coil forming a meta-stable prefusion intermediate. The C-terminal heptad repeat (CHR) subsequently folds onto the hydrophobic grooves of the NHR coiled-coil to form a stable 6-helix bundle, which juxtaposes the viral and cellular membranes for fusion.

Inter-chain acyl transfer reaction in a peptide six-helical bundle: a chemical method for regulating the interaction between peptides or proteins.

An inter-helical acyl transfer specifically occurred between the C-and N-peptides of HIV gp41 after assembly of the six-helical bundle (6HB), forming an inter-helical covalent bond that greatly enhanced 6HB stability. In the reaction, the C-peptide was modified as an acyl donor, and the N-peptide served as an acyl acceptor.

Discovery of HIV fusion inhibitors targeting gp41 using a comprehensive α-helix mimetic library.

The evaluation of a comprehensive α-helix mimetic library for binding the gp41 NHR hydrophobic pocket recognizing an intramolecular CHR α-helix provided a detailed depiction of structural features required for binding and led to the discovery of small molecule inhibitors (K(i) 0.6-1.3 μM) that not only match or exceed the potency of those disclosed over the past decade, but that also exhibit effective activity in a cell-cell fusion assay (IC(50) 5-8 μM).