Synthesis,Biological Evaluation of 1,1‐Diarylethylenes as a Novel Class of Antimitotic Agents

The cytotoxic activities of 23 new isocombretastatin A derivatives with modifications on the B‐ring were investigated. Several compounds exhibited excellent antiproliferative activity at nanomolar concentrations against a panel of human cancer cell lines. Compounds isoFCA‐4 ( 2 e ), isoCA‐4 ( 2 k ) and isoNH₂CA‐4 ( 2 s ) were the most cytotoxic, and strongly inhibited tubulin polymerization with IC₅₀ values of 4, 2 and 1.5 μM , respectively. These derivatives were found to be 10‐fold more active than phenstatin and colchicine with respect to growth inhibition but displayed similar activities as tubulin polymerization inhibitors. In addition, cell cycle arrest in the G₂/M phase and subsequent apoptosis was observed in three cancer cell lines when treated with these compounds. The disruptive effect of 2 e , 2 k and 2 s on the vessel‐like structures formed by human umbilical vein endothelial cells (HUVEC) suggest that these compounds may act as vascular disrupting agents. Both compounds 2 k and 2 s have the potential for further prodrug modification and development as vascular disrupting agents for treatment of solid tumors.     

Influence of addition of green tea and green coffee extracts on the properties of fine yeast pastry fried products

This study investigated the influence of antioxidants of green tea aqueous extract (GTE) and green coffee aqueous extract (GCE) in concentrations of 0.25, 0.5 and 1 g·100 g^? 1 on the nutritional properties of fine yeast pastry fried products such as donuts. Yeast donuts were made according to the traditional processing technology. In fried donuts physical properties (water activity, pH, hardness and color with the use of instrumental methods) as well as sensory properties were established. Moreover, quality of fat extracted from donuts (composition of fatty acids and peroxide value), content of acrylamide, composition of polyphenols and antioxidant activity were analyzed. Obtained extracts of GTE and GCE contained 26 and 41% of polyphenols, respectively, and the degree of polyphenol degradation during production of donuts was less when the dilution in dough was greater. Both tests indicated that the highest antioxidant activity had donuts with the highest analyzed addition of extract, however depending on the applied test or GTE or GCE had better antioxidant properties. Fatty acid composition was the most beneficial when the addition of GTE and GCE was on a level of 0.25 and 0.5 g·100 g^? 1, respectively. In fried donuts relatively low amounts of acrylamide were obtained, amounting to 18–46 μg·kg^? 1. Only the lowest addition of GTE and the highest addition of GCE caused an increase of acrylamide content in donuts, while all other levels of added extracts caused a decrease in the content of formed acrylamide.     

Fabrication of nanoporous TiO2 by electrochemical anodization

The formation of self-organized porous titania is achieved by electrochemical anodization under a potentiostatic regime. Anodic titanium oxide (ATO) was fabricated by a three-step self-organized anodization of the Ti foil in an ethylene glycol electrolyte containing 0.38 wt% of NH₄F and 1.79 wt% of H₂O. Anodizing was carried out at the constant cell potential ranging from 30 to 70 V at the temperature of 20 °C. It was found that nanoporous TiO₂ arrays can be obtain only after a short duration of the third step (10 min). The influence of anodizing potential on the structural parameters of porous anodic titania including pore diameter, interpore distance, wall thickness, porosity and pore density was extensively studied. The linear dependencies between interpore distance, pore diameter and wall thickness upon the anodizing potential were found. The regularity of pore arrangement was monitored qualitatively by fast Fourier transforms (FFTs) of top-view FE-SEM images. It was found that the best arrangement of nanopores is observed at 40 V. This finding was confirmed by the analysis of pore circularity. The highest circularity of pores was observed once again at 40 V.     

Visual variant of Alzheimer's disease: Distinctive neuropsychological features.

A subgroup of patients with probable Alzheimer disease (AD) reported a history of isolated visual disturbances (VS) early in the course of disease, without the characteristic memory complaints. Brain imaging and neuropathologic studies indicated that this subgroup had larger involvement of visual cortical areas and relative sparing of temporal. frontal, and limbic structures compared with classic AD. Consistent with these findings, the authors hypothesized that the cognitive deficits in this subgroup would be distinctly different from those seen in more typical AD patients. The authors studied 10 probable AD patients with VS (AD&±&|S), 22 patients without VS (AD–), and 25 healthy controls with a neuropsychological test battery. Compared with AD–, AD&±&|S patients performed significantly better on tests of verbal memory and had greater impairment on tests of visuospatial skills, suggesting a distinct pattern of cognitive dysfunction consistent with metabolic and neuropathologic reports. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discrimination of the threat of direct versus tangential approach to the nest by incubating herring and great black-backed gulls.

Examined the ability of incubating herring (Larus argentatus) and black-backed (L. marinus) gulls to discriminate between people walking directly toward their nests and those merely walking tangentially by their nests. Study groups varied in their habitat (open vs vegetated) and previous exposure to human disturbance. Herring gulls responded when the experimenter (E) was at a greater distance from the nest if the approach was directly toward the nest with the person looking at the incubating bird, and gulls in disturbed areas responded sooner than birds in undisturbed areas. In habitats with low visibility (dense bush cover), the gulls could not see E early enough to show different responses to the 2 treatments. Black-backed gulls nested only in undisturbed areas, and only slight differences were evident in the distance at which they left the nest. However, they called more when E was approaching the nest directly. In this study, gulls habituated to the continual presence of humans by modifying their responses, but even habituated birds continued to reassess the potential danger of a nearby human and perceived subtle differences between a direct and a tangential approach. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prevalence of microbial biofilms on selected fresh produce and household surfaces

Investigations of biofilms in domestic environments are sparsely represented in the literature. In this study, samples of various household surfaces, including food, laundry and kitchen items, were analyzed for evidence of biofilm presence. Visualization of the surfaces was carried out using cryostage scanning electron microscopy (CSEM) and light microscopy. Qualitative evidence of the presence of biofilm formation was obtained from all of the sample groups analyzed, suggesting the widespread existence of microorganisms in biofilms on domestic surfaces. This suggests that biofilms may be important in household hygiene, and highlights the need for standardized, approved biofilm methods suitable for consumer products testing.     

Geochemical signature of contaminated sediment remobilization revealed by spatially resolved X-ray microanalysis of annual rings of Salix nigra

An X-ray microprobe was used to determine the concentration and distribution of Ni, U, and other metals within annual rings of willows (Salix nigra L.) from a former de facto radiological settling basin (Steed Pond; SP) and a depositional environment downstream (Tims Branch; TB) on the Savannah River Site (SRS). Geochemical and historical information about both areas are well documented. Following spillway breaches at SP in 1984 and the early 1990s, TB is inundated with contaminated sediments during storms. Bulk elemental composition of tree cores was determined using ICP-OES. Synchrotron X-rayfluorescence (SXRF) analysis showed that the metal contents of SP and TB cores were an order of magnitude higher than those from a reference site. TB cores were enriched with Ni in 1984 and 1991, corresponding with SP spillway breaches (containing 790 mg kg(-1) Ni in 1991). Cores from SP exhibited an extremely high Ni peak in 1996, approximately 5000 mg kg(-1), even though contaminant levels at SP did not change. The geochemical signature of contaminants recorded in TB annual rings reflected the significant sediment remobilization events consistent with the detailed history of the site, and at concentrations relative to their proximity to the source term. However, physiological processes occurring within impacted trees strongly influence the chronological accuracy of dendroanalysis and must be investigated further.     

DNA hybridization using surface plasmon-coupled emission

We describe a new approach to measuring DNA hybridization using surface plasmon-coupled emission (SPCE). Excited fluorophores are known to couple with surface oscillations of electrons in thin metal films, typically 50 nm thick silver on a glass prism. These surface plasmons then radiate into the glass at a sharply defined angle determined by the emission wavelength and the optical properties of the glass and metal. This radiation has the same spectral profile as the emission spectrum of the fluorophores. We studied the emission due to Cy3-labeled DNA oligomers bound to complementary unlabeled oligomers which were themselves bound to the metal surface. Hybridization resulted in SPCE due to Cy3-DNA into the prism. Directional SPCE was observed whether the sample was illuminated from the sample side or through the glass substrate at the surface plasmon angle for the excitation wavelength. A large fraction of the total potential emission is coupled to the surface plasmons resulting in improved sensitivity. When illuminated through the prism at the surface plasmon angle, the sensitivity is increased due to the enhanced intensity of the resonance evanescent field. It is known that SPCE depends on proximity to the silver surface. As a result, changes in emission intensity are observed due to fluorophore localization even if hybridization does not affect the quantum yield of the fluorophore. The use of SPCE resulted in suppression of interfering emission from a noncomplementary Cy5-DNA oligomers due to weaker coupling of the more distant fluorophores with the surface plasmons. We expect SPCE to have numerous applications to nucleic acid analysis and for the measurement of bioaffinity reactions.     

Identification of water-soluble selenium-containing proteins in selenized yeast by size-exclusion-reversed-phase HPLC/ICPMS followed by MALDI-TOF and electrospray Q-TOF mass spectrometry

An approach to speciation of selenium incorporated in yeast proteins was developed. The tryptic digest of a water-soluble protein fraction isolated by size-exclusion chromatography was analyzed by reversed-phase HPLC/ICPMS. The selenopeptides selected owing to the detector's elemental specificity were then analyzed by MALDI-TOFMS in order to select target ions for collision-induced dissociation MS. The latter, carried out with an electrospray Q-TOF spectrometer, enabled the sequencing of the selenopeptides detected by HPLC/ICPMS. The approach allowed for the first time the identification of a family of Se-containing proteins resulting from the replacement by selenomethionine of 2-9 methionine residues in a salt-stress-induced protein SIP18 (Mr 8874). The presence of these proteins was confirmed by MALDI-TOFMS of the original (nondigested) protein fraction. Another selenium protein identified was a heat-shock protein HSP12 (Mr 11693) in which the only methionine residue was replaced by selenomethionine. These two Se-containing proteins accounted for more than 95% of selenium in the water-soluble protein fraction.     

Pressure distribution in an assembly of wooden cylinders with various aspect ratios under uniaxial confined compression

Understanding how forces propagate in granular assemblages is important for equipment design and process control in many technologies. Yet, it remains poorly understood. In this study, a cuboidal assembly comprising cylinders of various lengths (aspect ratios AR ranging from 0.9 to 3.6) were subjected to uniaxial confined compression tests. Samples were vertically compressed until the top platen exerted a pressure of 50 kPa on the uppermost particles. This maximum pressure corresponds to the hydrostatic pressure of an approximately 15 m high column of chopped wood that may be encountered in real storage structures. The nonlinear loading curves were obtained depended on the aspect ratios of the cylinders. The modulus of elasticity, calculated from the linear elastic part of the stress–strain curve, monotonically decreased from 10.2 to 8.6 MPa as the aspect ratio increased from 1.2 to 3.6. The elastic modulus and volume fraction exhibited similar trends as functions of the aspect ratio. The horizontal-to-vertical pressure ratio was calculated as the horizontal pressure exerted on the wider walls to the vertical pressure exerted on the top lid during loading–unloading cycles. For ARs up to 3.6, the pressure ratio was approximately 0.31; for the longest cylinders (AR = 3.6), it decreased to approximately 0.27, probably because the assumption of the representative chamber volume was invalidated at this AR.