A quasiclassical trajectory study of final state distributions in collisions of fast H(D) atoms with HF(DF)Detailed results of the converged full-dimensional 6D quantum calculations of the vibrational levels of ͑HF͒ 2 , ͑DF͒ 2 , and HFDF, for total angular momentum Jϭ0, are presented. The ab initio 6D potential energy surface by Quack and Suhm was employed. This study provides a comprehensive description of the bound state properties of the HF dimer and its isotopomers, including their dissociation energies, frequencies of the intermolecular vibrations, tunneling splittings, and extent of wave function delocalization. Quantum number assignment of the calculated eigenstates by plotting different cuts through the wave functions worked rather well for ͑HF͒ 2 , but proved to be much harder for ͑DF͒ 2 and HFDF, indicating stronger vibrational mode mixing in these species. The ground-state tunneling splitting for the HF dimer from our exact 6D calculations, 0.44 cm Ϫ1 , is very close to that from a previous 4D rigid-rotor calculation, 0.48 cm Ϫ1 ͓J. Chem. Phys. 99, 6624 ͑1993͔͒. This is in disagreement with the result of a recent 6D bound state calculation for ͑HF͒ 2 by Necoechea and Truhlar, which gave a ground-state tunneling splitting a factor of 3.7 times larger than the 4D result.
The fabrication of a conducting polyaniline (PANi) matrix based on a template of polystyrene (PS) latex is of interest from an academic and application viewpoint. In this Full Paper, we propose a distinctly novel strategy, which involves swelling followed by diffusion and polymerization at the interface, to fabricate PANi‐coated PS microspheres with uniform size and well‐defined shape, regardless of the type of “naked” PS seed particles. Compared to the widely used conventional synthetic protocol, this method affords much more effective control over the structure and morphology of the resultant composites by simply changing the aniline/PS weight ratio or the rate of addition of the doping agent. In addition, it guarantees the easy and successful production of a hollow nanostructure of a conducing polymer with a uniform, intact shell. The synthesized composites have been characterized using Fourier transform infrared spectroscopy, C, H, and N elemental microanalyses, and transmission electron microscopy. The mechanism governing the formation of the composites is discussed.
A heterocoagulation strategy based on colloidal steric stabilization theory has been developed, through which polystyrene (PS) and silica (SiO(2)) particles without any surface modification or functionalization self-assembled rapidly via solution to afford nanocomposite particles with raspberry-like morphology. The formation mechanism is fully studied on the basis of a thermodynamic analysis. The soluble stabilizer and the solvent quality are the main determining factors, which have a significant influence on this self-assembly process and the silica coverage of resultant composites. The relative size of PS to SiO(2) candidates also has the effect of control on the extent of self-assembly. Furthermore, this strategy can be applied to fabricate a broad range of composite materials, including PS/TiO(2), PS/AgI, as well as PS/PS composites.
Our original findings, showing the effectiveness of active and passive tau immunizations in mouse models, have now been confirmed and extended by many groups, with several clinical trials underway in Alzheimer's disease and progressive supranuclear palsy. Here, we report on a unique and sensitive two-photon imaging approach to concurrently study the dynamics of brain and neuronal uptake and clearance of tau antibodies as well as the acute removal of their pathological target in live animals. This in vivo technique is more sensitive to detect clearance of pathological tau protein than western blot tau analysis of brain tissue. In addition to providing an insight into the mechanisms involved, it allows for an efficient in vivo assessment of the therapeutic potential of tau antibodies, and may be applied to related protein misfolding diseases.
This study focused on the characterization of fluorescent-dissolved organic matter and identification of specific fluorophores in textile effluents. Samples from different textile wastewater treatment plants were characterized by high-performance liquid chromatography and size exclusion chromatography as well as fluorescence excitation-emission matrix spectra. Despite the highly heterogeneous textile effluents, the fluorescent components and their physicochemical properties were found relatively invariable, which is beneficial for the combination of biological and physicochemical treatment processes. The humic-like substance with triple-excitation peaks (excitation (Ex) 250, 310, 365/emission (Em) 460 nm) presented as the specific fluorescence indicator in textile effluents. It was also the major contributor to UV absorbance at 254 nm and resulted in the brown color of biologically treated textile effluents. By spectral comparison, the specific fluorophore in textile effluents could be attributed to the intermediate structure of azo dyes 1-amino-2-naphthol, which was transferred into the special humic-like substances during biological treatment.
BackgroundNumerous studies have shown that the extent of pathological tau protein in the brain correlates strongly with the severity of Alzheimer’s dementia at the time of death, and similar association with functional phenotypes have been seen in other tauopathies. In recent years, several dye‐based imaging probes with selectivity for tau aggregates have been developed. However, all are β‐sheet binders with varying affinity for different amyloids, and thereby lack specificity for tau lesions. In contrast, single domain antibodies (sdAbs) are specific for their target and because of their small size have much greater access into the brain than standard whole antibodies.MethodTo examine sdAbs’ suitability as non‐invasive in vivo imaging probes for tauopathies, we immunized a llama with a full‐length recombinant tau protein followed by boosters with human brain‐derived pathological tau proteins. Phage display libraries were generated from its peripheral blood mononuclear cells and screened for binding to tau proteins using various assays, resulting in a prototype sdAb deemed promising for in vivo imaging. Subsequently, this anti‐tau sdAb was labeled with a near‐infrared tag (680 nm), and injected intravenously in tauopathy and control mice, followed by imaging using an In Vivo Imaging System (IVIS). After the imaging, brains were extracted for tissue analysis.ResultIntravenous injection of labeled sdAb resulted in a strong in vivo brain signal detected through the intact head in two different models of transgenic tauopathy mice, but not in wild‐type or transgenic α‐synucleinopathy mice. Importantly, the in vivo brain signal correlated strongly with insoluble (r = 0.9839, p < 0.0001) and soluble (human tau (CP27) and phospho‐tau (PHF1): r = 0.9603 and 0.9459, p < 0.0001) tau protein within the brain. Furthermore, postmortem analysis revealed extensive co‐localization of the sdAb imaging probe with tau aggregates within neurons in the endosomal‐lysosomal system, indicating their interaction in these degradation pathways.ConclusionOverall, this specific sdAb imaging ligand has great potential as an in vivo diagnostic marker for Alzheimer's disease and related tauopathies, and sdAb‐based imaging may be applicable to a variety of protein conformational disorders.
Brassica rapa ssp. campestris (Brassicaceae) is a conical, deep purple, edible root vegetable commonly known as a turnip. We initiated phytochemical and pharmacological studies to search for biological active compounds from the roots of B. rapa ssp. campestris. We isolated a novel phenanthrene derivative, 6-methoxy-1-[10-methoxy-7-(3-methylbut-2-enyl)phenanthren-3-yl]undecane-2,4-dione, named brassicaphenanthrene A (3) along with two known diarylheptanoid compounds, 6-paradol (1) and trans-6-shogaol (2), through the repeated silica gel (SiO2), octadecyl silica gel, and Sephadex LH-20 column chromatography. The chemical structures of the compounds were determined by spectroscopic data analyses including nuclear magnetic resonance, mass spectrometry, ultraviolet spectroscopy, and infra-red spectroscopy. All compounds exhibited high inhibitory activity against the growth of human cancer lines, HCT-116, MCF-7, and HeLa, with IC50 values ranging from 15.0 to 35.0 μM and against LDL-oxidation with IC50 values ranging from 2.9 to 7.1 μM.
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