Studies on peroxidized lipids. V. Formation and characterization of 1,4-dihydropyridine-3,5-dicarbaldehydes as model of fluorescent components in lipofuscin

We investigated fluorescence properties of 1,4-dihydropyridine-3,5-dicarbaldehydes and their formation in mild reaction of primary amines and malonaldehyde, in order to clarify the role of malonaldehyde in the formation of fluorescent components of lipofuscin. The compounds exhibited fluorescence with excitation maxima at 375–405 nm and emission maxima at 435–465 nm, which was similar to those of lipofuscin and the fluorescent substances derived from the reaction of oxidized fatty acids with primary amines. Fluorescence of the compounds was greatly affected in acidic medium and little influenced in alkaline medium or by the metal chelator. The compounds lost fluorescence by treatment with sodium borohydride. They were inert to thiobarbituric acid reaction. Some of the fluorescence properties of the compounds were different from those of lipofuscin and the related fluorescent substances. Mild reaction of methylamine with pure malonaldehyde gave a single fluorescent compound, 1,4-dimethyl-1,4-dihydropyridine-3,5-dicarbaldehyde (Ia), and the reaction with the acid hydrolysate of tetramethoxypropane gave Ia and 1-methyl-4-(dimethoxyethyl)-1,4-dihydropyridine-3,5-dicarbaldehyde (IIa), the latter being produced from the impurity in the hydrolysate. These reactions produced a non-fluorescent Schiff base, a 1∶1-adduct of methylamine and malonaldehyde (IIIa), as a major product. It looks unlikely that malonaldehyde is the only product of lipid oxidation that produces fluorescent components in lipofuscin complex.     

The effect of airflow pattern on filter breakthrough in physical adsorption

The Wheeler-Jonas (WJ) model for prediction of the protection capacity of organic vapor filters under a fixed airflow was extended to breathing-simulation, pulsating flow. Breakthrough curves of dimethyl-methyl phosphonate (DMMP) and decane were measured under fixed flow and sinusoidal flow. A linear dependence of ln(C_X/C₀) on the breakthrough time (t_B) was observed in all the experiments, indicating that the concepts of critical bed weight (W_C) and dynamic adsorption capacity (W_E) as defined by the WJ model are applicable to pulsating flow as well. W_E was found to be almost unchanged by the flow pattern, whereas W_C was considerably larger (by 7-44%) at pulsating flow compared to fixed flow with the same average rate. Thus, shifting from fixed flow to pulsating flow may shorten t_B significantly. The effect of the flow type on t_B increases with the ratio of the critical weight to the total bed weight. For a high protection level (C₀/C_X=60?000), the protection capacity of personal NBC canisters was reduced by up to 15% upon shifting from fixed to pulsating flow.     

Plasma surface interaction in PACVD and PVD systems during TiAlBN nanocomposite hard thin films deposition

In a PACVD system, titanium alloys were exposed to inductive radio-frequency (RF) plasmas of H₂ + N₂ and Ar + BCl₃+H₂ + N₂ gas mixtures for their nitriding and boron nitride respectively. Hard nanocomposite thin films of TiAlN and TiAlBN were formed on Ti-6Al-4V alloys in an inductive RF plasma of Ar + H₂ + N₂ and Ar + 3.5 vol.% of BCl₃ + H₂ + N₂, respectively. The substrates were grounded, i.e., self-biased, during plasma thin film formation for 30 min each. TiAlBN was deposited by sputtering in a reactive PVD system. A quadrupole mass spectrometer (QMS) sampled the plasma at a constant distance of 0.5 cm from the sample surface in real time. The mass species (m/e) at 0.5 cm were recorded during the deposition process. To separate the particles reaching the substrate surface from those leaving it, the nanocomposite thin films coated samples of Ti alloys were introduced in an RF plasma of Ar + H₂ mixture without the presence of N₂ and BCl₃ and negatively biased up to V_b = − 350 V. The QMS at 0.5 cm measures the etched and sputtered species from the surface of the coated samples. Comparing the QMS results between the grounded samples with the monomers in the RF plasma and the negatively biased voltage samples without monomers in the Ar + H₂ plasma the net plasma surface interactions (PSI) were evaluated. The behavior of the coating process of nanocomposite thin films of TiAlN and TiAlBN on the Ti alloy samples is strongly dependent on the plasma surface phenomena.     

Design optimization and development of CNC lathe headstock to minimize thermal deformation

This paper has investigated an approach to reduce and compensate thermal displacement for high accuracy NC lathes. An efficient design and optimization method is proposed for a headstock structure design of NC lathes to minimize the thermal displacement of the spindle center position. Compared to the existing empirical methods, this method saves development time and cost. The Taguchi method and FEA method are used to identify the optimal headstock structure. The proposed method is verified by evaluating the spindle center transition of the headstock according to the optimization results.     

Potential induced pH change: Towards electrochemical coating of medical implants by organic nanoparticles

The electrochemical deposition of organic nanoparticles on conducting surface, such as a coronary stents, in the absence of a polymeric matrix is demonstrated. A novel approach, whereby pH-responsive organic nanoparticles coagulate on a conducting surface as a result of applying positive potential, has been studied. Specifically, latex nanoparticles stabilized by sodium oleate in aqueous solutions were deposited by applying a positive potential that oxidized the water and caused the decrease of pH on various conducting surfaces. It was found that the applied potential, its duration and the concentration of the dispersed nanoparticles govern the deposition characteristics of the coating.This generic approach allows coating objects with complex geometries with thickness ranging from nanometers to microns and therefore can be utilized for coating medical and other devices as well as for controlling drug release.     

Essential Amino Acid Composition of Fleshy Fruits Versus Maintenance Requirements of Passerine Birds

Nutritional analyses were performed on 27 fruit species that are eaten by frugivorous birds in east Mediterranean habitats in Israel. The essential amino acid (EAA) profile [compared by principal component analysis (PCA)] of these fruits indicated two distinct groups of fruits. The main group consisted of 23 species that were similar in their relatively low total EAA quantities and unbalanced EAA profiles. On average, the EAAs phenylalanine and tyrosine were most concentrated and histidine least (tryptophan was not measured). Comparing the relative amounts of EAAs in fruits with required amounts for maintenance of granivorous passerine birds revealed that these fruits are deficient in all or most EAAs. The sulfur-containing amino acids (methionine and cystine) were most limiting relative to the required amount (41–61% below requirement), while four others (arginine, lysine, isoleucine, and leucine) were severely deficient (30–37% below requirement). These results complement reports suggesting that frugivorous birds have lower total protein demands than granivores. The second group of four fruit species had relatively high total EAA contents. Each of these fruits appeared to contain especially large quantities of some EAAs, but it was uncertain whether some high concentrations could have resulted from interactions in the pulp during preparation and chemical analysis.     

Internal stress in TiAlBN at high temperatures

Hard TiAl(B)N coatings were deposited by radio-frequency magnetron sputtering in reactive mode in an argon and nitrogen environment using a TiAlB target with 12 at.% of boron. The deposition was carried out under ion bombardment at various negative bias voltages in the range of 0 to 170 V, and at substrate temperatures between 453 and 523 K. The internal stress in the coatings was studied at room temperature as a function of annealing temperatures in ambient air up to 1123 K. The heating duration was 2 h followed by annealing for 1 h. The microstructure, phase composition and hardness were also studied prior to and after annealing.We found that the TiAlBN coatings consist of TiAl₃ and TiN phases. With increasing ion bombardment, the structure of the coatings changes from columnar to nano-scale features. Prior to annealing we also observed a correlation between the residual stress and hardness. After annealing, the compressive stresses of the TiAl(B)N coatings decreased from 1.0 GPa to less than 0.2 GPa, while the hardness remained constant or increased from ∼ 10 GPa to ∼ 25 GPa. The hardness increase of the coatings after annealing is related to a self-hardening effect.     

Intergroup competition for public goods: Effects of unequal resources and relative group size.

Studied single-stage intergroup competition for public goods in small groups with total resources of equal size and binary contributions. In Experiment 1, the two competing groups were of equal size, but the individual resources (endowments) within each group differed from one member to another. The main finding was a negative relation between the endowment size and the likelihood of contribution. In Experiment 2, the ratio of public good to endowment was the same for all members of both groups, but sizes of the groups were unequal. We found no effect of group size per se on level of contribution. Theoretical and methodological implication of the findings are briefly discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of chemotherapy on FDG uptake by human cancer xenografts in nude mice

This study evaluated the use of PET with 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG) for monitoring chemotherapy effects, using a human cancer xenograft (poorly differentiated human gastric cancer) in vivo model. METHODS: Tumor 18F-FDG uptakes and sizes were measured after administrating mitomycin (MMC), cisplatin (CDDP) and adriamycin (ADR) to xenograft-bearing nude mice and compared with 18F-FDG tumor uptake and tumor size in a non-therapy group. The correlation between the uptake and size was also assessed. RESULTS: The largest reduction in tumor size after chemotherapy occurred in the MMC administered group, followed by the CDDP case, with no reduction in the ADR group as compared to the controls. Fluorine-18-FDG tumor uptake after chemotherapy was also decreased in the MMC and CDDP groups, in that order, but not in the ADR case. With MMC and CDDP, size reduction became significant on Days 8 or 11, whereas 18F-FDG tumor uptake had already been decreased on Days 3 or 7. CONCLUSION: Fluorine-18-FDG uptake decreases in parallel to the efficacy of anticancer agents and correlates with subsequent morphologic changes. We conclude that 18F-FDG PET tumor images are indeed useful for monitoring the effects of cancer chemotherapy.     

Personal supercomputing by using transputer and Intel 80860 in plasma engineering

Transputer (T800) and 64-bit RISC Intel 80860 (i860) added on a personal computer can be used as an accelerator. When 32-bit T800s in a parallel system or 64-bit i860s are used, scientific calculations are carried out several ten times as fast as in the case of commonly used 32-bit personal computers or UNIX workstations. Benchmark tests and examples of physical simulations using T800s and i860 are reported.