Nanocrystalline Powders Based on ZrO2 for Biomedical Applications and Power Engineering

An 80 mass% ZrO₂ ― 20 mass% Al₂O₃ powder was produced using a complex method which integrates sol-gel technology and hydrothermal synthesis. The specific surface areas of the powder varied from 39 to 5.3 m²/g depending on the thermal treatment conditions. Metastable F-ZrO₂ formed after powder annealing at 400°C. The phase transformation F-ZrO₂ → T-ZrO₂ (traces of M-ZrO₂) occurred under powder thermal treatment from 700 to 1000°C. Only Θ-Al₂O₃ was detected under experimental conditions. The powder was characterized by sintering activity. Operating the processes under powder thermal treatment in the ZrO₂ ― Y₂O₃ ― CeO₂ ― Al₂O₃ system will allow one to produce a variety of ceramic microstructures from fine-grained to “self-reinforced.” These powders can be used in manufacturing surgical cutting tools as well as in ceramic passive bioimplants and solid electrolytes for fuel elements.     

Tunable dual-wavelength all-PM fiber ring laser

A multisegment all-PM fiber ring laser is constructed to demonstrate a tunable dual-wavelength laser source with continuous tuning in absolute wavelength and discrete tuning in wavelength spacing. The tuning method is based on birefringence filtering properties of a segmented all-PM fiber ring resonator. Using this method, we show a discrete wavelength spacing of dual-wavelength output from 0.9 to 2.5 nm, and continuous wavelength tuning over a few nanometers. The demonstrated dual-wavelength laser can be easily modified to tune over a greater wavelength spacing and absolute wavelength range     

Palladium‐Catalyzed Decarbonylative Dehydration of Fatty Acids for the Production of Linear Alpha Olefins

A highly efficient palladium‐catalyzed decarbonylative dehydration reaction of carboxylic acids is reported. This method transforms abundant and renewable even‐numbered natural fatty acids into valuable and expensive odd‐numbered alpha olefins. Additionally, the chemistry displays a high functional group tolerance. The process employs a low loading of palladium catalyst and proceeds under solvent‐free and relatively mild conditions.

     

Self‐Assembly of Ferromagnetic Organic–Inorganic Perovskite‐Like Films

Perovskite‐based organic–inorganic hybrids hold great potential as active layers in electronics or optoelectronics or as components of biosensors. However, many of these applications require thin films grown with good control over structure and thickness—a major challenge that needs to be addressed. The work presented here is an effort towards this goal and concerns the layer‐by‐layer deposition at ambient conditions of ferromagnetic organic–inorganic hybrids consisting of alternating CuCl₄‐octahedra and organic layers. The Langmuir‐Blodgett technique used to assemble these structures provides intrinsic control over the molecular organization and film thickness down to the molecular level. Magnetic characterization reveals that the coercive field for these thin films is larger than that for solution‐grown layered bulk crystals. The strategy presented here suggests a promising cost effective route to facilitate the excellently controlled growth of sophisticated materials on a wide variety of substrates that have properties relevant for the high density storage media and spintronic devices.     

Gold nanorods with a hematoporphyrin-loaded silica shell for dual-modality photodynamic and photothermal treatment of tumors in vivo

Nanocomposites （NCs） consisting of a gold nanorod core and a mesoporous silica shell doped with hematoporphyrin （HP） have been fabricated in order to improve the efficiency of cancer treatment by combining photothermal and photodynamic therapies （PDT ＋ PTT） in vivo. In addition to the long-wavelength plasmon resonance near 810-830 nm, the fabricated NCs exhibited a 400-nm absorbance peak corresponding to bound HP, generated singlet oxygen under 633-nm excitation near the 632.5-nm Q-band, and produced heat under a 808-nm near-infrared （NIR） laser irradiation. These modalities were used for a combined PDT ＋ PTT treatment of large （about 3 cm3） solid tumors in vivo with a xenorafted tumor rat model. NCs were directly injected into tumors and irradiated simultaneously with 633-nm and 808-nm lasers to stimulate the combined photodynamic and photothermal activities of NCs. The efficiency of the combined therapy was evaluated by optical coherence tomography, histological analysis, and by measurements of the tumor volume growth during a 21-day period. The NC-mediated PDT led to weak changes in tissue histology and to a moderate 20% decrease in the tumor volume. In contrast, the combined PDT ＋ PTT treatment resulted in the large-area tumor necrosis and led to dramatic decrease in the tumor volume.     

Viral quantitative capillary electrophoresis for counting intact viruses

The quantification of a virus plays an important role in vaccine development, clinical diagnostics, and environmental contamination assays. In all these cases, it is essential to calculate the concentration or number of intact virus particles (ivp) and estimate the degree of degradation and contamination of virus samples. In this work, we propose a cost-efficient, robust method for the quantification and characterization of intact viruses based on capillary zone electrophoresis. This separation method is demonstrated on vaccinia virus (VV) with oncolytic properties. After virus sample preparation, the solution contains intact VV as well as broken viruses and residual DNA from the host cell used for preparation. Regulatory requirements limit the amount of the host cell DNA that can be present in vaccines or human therapeutics. We apply capillary electrophoresis to separate intact virus particles and the residual DNA and to measure the level of virus contamination with DNA impurities. Intercalating YOYO-1 dye is used to detect the encapsulated and free DNA by laser-induced fluorescence. After soft lysis of VV with proteinase K, all encapsulated DNA is dissolved to the free DNA. The change in peak areas and a DNA calibration curve help determine the initial concentration of intact viruses. This viral quantitative capillary electrophoresis (Viral qCE) is able to quantify the oncolytic vaccinia virus in the range of 10(6) to 10(12) ivp/mL.     

4‐Cyanoresorcinol‐Based Bent‐Core Mesogens with Azobenzene Wings: Emergence of Sterically Stabilized Polar Order in Liquid Crystalline Phases

A new series of azobenzene containing bent‐core molecules incorporating 4‐cyanoresorcinol as the central core unit exhibiting cybotactic nematic, rectangular, columnar, and different types of tilted smectic (SmC) phases are synthesized. The mesophase behavior and phase structures are characterized in bulk and freely suspended films using a variety of experimental techniques. Depending on the chain length and temperature a series of different mesophases is observed in these compounds, ranging from cybotactic nematic via paraelectric SmC phases, polarization randomized SmC_sP_R phases to ferroelectric and antiferroelectric SmC phases, associated with increasing size and correlation length of the polar domains. Spontaneous formation of chiral domains is observed in the paraelectric SmC and the SmC_sP_R phases and discussed in relation with superstructural chirality, bend elastic constants, and surface effects.     

A study of photooptical processes in photosensitive cholesteric azobenzene-containing polymer mixture under an action of the polarized and nonpolarized light

New liquid crystalline cholesteric mixture consisting of azobenzene-containing side-chain copolymer and the chiral low-molar-mass dopant (5%) was prepared and its properties were studied. It was shown that freshly prepared spin-coated thin films are optically isotropic. However, the films possess a noticeable circular dichroism with a maxima corresponding to the absorbance of the nonchiral azobenzene fragments. This phenomenon is an evidence for the existence of the helical supramolecular structure elements in the mixture films. An annealing of the films at temperatures above the glass transition leads to the strong increase in the circular dichroism due to formation of the perfect cholesteric phase. UV light irradiation results in the E-Z isomerization of azobenzene groups and the significant drop in circular dichroism values (almost to zero) both for the fresh and the annealed films that is associated with the transition from cholesteric to the fully isotropic state. An action of polarized UV and visible light leads to the photoorientation of azobenzene groups perpendicular to the electric vector of the polarized light. Kinetic features of the photoorientation processes in cholesteric phase in comparison with nematic systems were studied. It has been experimentally found that the helical order to some extent prevents the photoorientation of the side groups. Upon UV irradiation of the thick, planarly-oriented films of the mixture at temperatures higher than glass transition, the selective light reflection maximum is shifted to the long-wavelength spectral region. All photoinduced phenomena occurring in the mixture are thermally reversible and annealing of the films at temperatures above glass transition results in the back recovery to the cholesteric nonoriented state and to the initial helix pitch value.     

电致发光显示器插上了有机翅膀

电致发光显示（ELD）技术由于使用了有机材料，形成了一种切实可行的高效对比度增强技术，使ELD从它原有的工业小环境中被营救出来。     

Prion‐associated proteins in yeast: comparative analysis of isogenic [PSI+] and [psi−] strains

A large group of prion‐associated proteins was identified in yeast cells using a new approach, comparative analysis of pellet proteins of crude cell lysates in isogenic strains of Saccharomyces cerevisiae differing by their prion composition. Two‐dimensional (2D) electrophoresis followed by MALDI analysis of the pellet proteins of [PSI⁺] and [psi^?] strains after prion elimination by GuHCl and prion transmission by cytoduction permitted identification of ca. 40 proteins whose aggregation state correlated with the change of prion(s) content. Approximately half of these proteins belonged to chaperones and to enzymes of glucose metabolism. Chaperones are known to be involved in prion metabolism and are expected to be present in prion‐containing aggregates, but glucose metabolism enzymes are not predicted to be present. Nevertheless, several recent data suggest that their presence is not incidental. We detected six proteins involved in oxidative stress response and eight in translation. Also notable is a protease. Most of the identified proteins seem to be prion‐associated, but we cannot exclude the possibility that several proteins may propagate as prions. Copyright © 2009 John Wiley & Sons, Ltd.