Effects of membrane charges and hydroperoxides on Fe(II)-supported lipid peroxidation in liposomes

The processes in producing a lag phase in Fe²⁺-supported lipid peroxidation in liposomes were investigated. Incorporation of phosphatidylserine (PS) or dicetyl phosphate (DCP) into phosphatidylcholine [PC(A)] liposomes, which have arachidonic acid, produced a marked lag phase in Fe²⁺-supported peroxidation, where PS was more effective than DCP. Phosphatidylcholine dipalmitoyl [PC(DP)] with a net-neutral charge was still effective in producing a lag phase, though weak. Increasing concentrations of PS, DCP, and PC(DP) prolonged the lag period. Initially after adding Fe²⁺, slight oxygen consumption occurred in PC(A)/PS liposomes including hydroperoxides, followed by a lag phase. An increase in the hydroperoxide resulted in a shortening of the lag period. The initial events of Fe²⁺ oxidation accompanied by oxygen consumption were dependent on the hydroperoxide content, but significant changes in diene conjugation and hydroperoxide levels at this stage were not found. The molar ratios of both dis-appeared Fe²⁺ and consumed O₂ to preformed hydroperoxide in liposomes with or withouttert-butylhydroxytoluene were constant, regardless of the different amounts of lipid hydroper-oxides. The antioxidant completely inhibited the propagation of lipid peroxidation in the lipid phase, following a lag phase. In a model system containing 2,2′-azobis (2-amidinopropane) dihydrochloride, Fe²⁺ were consumed. We suggest that Fe²⁺ retained at a high level on membrane surfaces play a role in producing a lag phase following the terminating behavior of a sequence of free radical reactions initiated by hydroperoxide decompositin, probably by intercepting peroxyl radicals.     

Racial/ethnic differences in breast cancer outcomes among older patients: Effects of physician communication and patient empowerment.

Objectives: To examine racial/ethnic disparities in older women's health-related quality of life (QoL) and type of breast cancer treatment as mediated by physician-level and individual-level variables. Methods: A cross-sectional survey of a population-based, consecutive sample identified through the Los Angeles Cancer Surveillance Program of Latina (n = 99), African American (n = 66), and White (n = 92) women aged 55 years or older (N = 257) between 3 and 9 months after primary breast cancer diagnosis and at least 1 month posttreatment. An exploratory, empirically developed latent variable model tested the relationships among demographic and physician-related variables, patient attitudes, and health-related outcomes. Health-related outcomes included QoL measures and receipt of breast conserving surgery (BCS). Results: Latinas reported less BCS and poorer QoL compared with Whites. Physician communication that can empower patients, in terms of patient efficacy in patient?physician interactions and breast cancer knowledge, mitigated racial/ethnic disparities in receipt of BCS. Physician emotional support was not related to patient cognitive empowerment and treatment outcomes. Medical mistrust in minority women was related to less self-efficacy and less positive coping, as well as, both directly and indirectly, to reduced QoL. Latinas reported poorer QoL in the tested model. Conclusion: Physician communication style, specifically information giving and participatory decision making, may empower older women with breast cancer and help mitigate racial/ethnic disparities in surgical treatment received. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of Epoxytrienes Derived from (3Z,6Z,9Z)-1,3,6,9-Tetraenes, Sex Pheromone Components of Arctiid Moths and Related Compounds

Cis-9,10-epoxy-(3Z,6Z)-1,3,6-henicosatriene has been identified from a pheromone gland of arctiid species, such as Hyphantria cunea. Since the diversity of lepidopteran species suggests that structurally related compounds of the 9,10-epoxide are also utilized as a sex pheromone components, epoxytrienes derived from (3Z,6Z,9Z)-1,3,6,9-tetraenes with a C₁₉–C₂₁ chain were systematically synthesized and characterized. While 1,2-epoxy-3,6,9-triene was not obtained, peracid oxidation of each tetraene produced a mixture of three cis-epoxides (3,4-epoxy-1,6,9-triene, 6,7-epoxy-1,3,9-triene, and 9,10-epoxy-1,3,6-triene), which were separable by LC as well as GC. Detailed inspection of the mass spectra of the C₁₉–C₂₁ epoxides indicated the following diagnostic ions for determining the chemical structures: m/z 79, M-70, and M-41 for the 3,4-epoxytrienes; m/z 79, 95, 109, and 149 for the 6,7-epoxytrienes; and m/z 79, 106, 120, M-121, and M-107 for the 9,10-epoxytrienes. Resolution of two enantiomers of each C₂₁ epoxytriene was accomplished by HPLC equipped with a chiral column, and analysis of the pheromone extracted from virgin females of H. cunea revealed the 9S,10R configuration of the natural epoxytriene as the same configuration of C₂₁ 9,10-epoxydiene, a main pheromone component of this species. GC-EAD analysis of the optically pure epoxides showed that the antennae of male H. cunea were stimulated more strongly (>100 times) by the (9S,10R)-isomers than the antipodes.     

Dietary total antioxidant capacity from different assays in relation to serum C-reactive protein among young Japanese women

Background

The association between dietary total antioxidant capacity (TAC) from different assays and serum C-reactive protein (CRP) has not been assessed in non-Western populations. We examined the association between dietary TAC and serum CRP concentration in young Japanese women using different four TAC assays.

Methods

The subjects were 443 young Japanese women aged 18?C22?years. Dietary TAC was assessed with a self-administered diet history questionnaire and the TAC value of each food using the following four assays: ferric reducing ability of plasma (FRAP); oxygen radical absorbance capacity (ORAC); Trolox equivalent antioxidant capacity (TEAC); and total radical-trapping antioxidant parameter (TRAP). Serum CRP concentrations were measured by highly sensitive nephelometry.

Results

The major contributor to dietary TAC was green, barley, and oolong tea (FRAP: 53%, ORAC: 45%, TEAC: 36%, and TRAP: 44%). The prevalence of elevated CRP concentrations (?? 1?mg/L) was 5.6%. TAC from FRAP was inversely associated with serum CRP concentrations (adjusted odds ratio [OR] for elevated CRP concentration in high [compared with low] dietary TAC group: 0.39 [95% confidence interval (CI): 0.16-0.98]; P?=?0.04). TAC from ORAC was inversely associated with CRP, although the association was not significant (OR: 0.48 [95% CI: 0.20-1.14]; P?=?0.10). TAC from TEAC was inversely associated with CRP (OR: 0.32 [95% CI: 0.12-0.82]; P?=?0.02), as was TAC from TRAP (OR: 0.31 [95% CI: 0.12-0.81]; P?=?0.02).

Conclusions

Dietary TAC was inversely associated with serum CRP concentration in young Japanese women regardless of assay. Further studies are needed in other populations to confirm these results.     

Influence of the porosity of hydroxyapatite ceramics on in vitro and in vivo bone formation by cultured rat bone marrow stromal cells

The in vitro and in vivo osteoblastic differentiation of rat bone marrow stromal cells (MSCs) was assessed on hydroxyapatite disks with 3 different porosities: 30%, 50%, and 70% (HA30, HA50, and HA70, respectively). MSCs obtained by 10-day culture of fresh bone marrow cells were subcultured for 2 weeks on 3 kinds of porous HA disks in the presence and absence of dexamethasone (Dex). After 2 weeks of subculture, alkaline phosphatase (ALP) activity and osteocalcin production of MSCs/HA composites with Dex were higher than those without, and increased with increasing porosity. The resultant bone tissue grafts “cultured-bone/HA constructs” were implanted subcutaneously into the backs of syngeneic rats, and harvested 1, 2, and 4 weeks after implantation. At 1 week, only cultured-bone/HA70 constructs exhibited expanded bone formation. At 2 and 4 weeks, active osteoblasts and progressive bone formation were observed morphologically in both cultured-bone/HA50 and HA70 constructs. At 4 weeks, bone tissue was observed even in cultured-bone/HA30 constructs. ALP activity and osteocalcin production also increased with increasing porosity and time after implantation. In this in vivo model, different scaffold porosity with similar crystal morphology of the apatite phase demonstrated marked differences in ability to support osteogenesis by implanted rat MSCs.     

Phase transformation and precipitation behavior of niobium component out of niobium-doped anatase-type TiO<Subscript>2</Subscript> nanoparticles synthesized via hydrothermal crystallization

The precipitation behavior of niobium component out of niobium-doped anatase-type TiO₂ and structural change in the course of heating were investigated. The samples were directly formed under hydrothermal conditions at 240 °C for 5 h in the presence of aqueous ammonia via crystallization from co-precipitates that were obtained from precursor solutions of TiOSO₄ and NbCl₅. The as-prepared niobium-doped anatase-type titania nanoparticles showed bluish color and absorption in the visible region, which was confirmed to be due to the presence of Ti(III) in the solid solutions using electron paramagnetic resonance measurement. The niobium-doped anatase-type titania existed stably without an appearance of any other phases after heating up to 500 °C for 1 h. In the course of heating at 500–800 °C, continual and clear decrease in the lattice parameters a ₀ and c ₀ of the anatase was observed, which was followed by the precipitation of Nb₂O₅ and TiNb₂O₇ out of the niobium-doped anatase, but the anatase phase was maintained without anatase-to-rutile phase transformation up to 850–1,000 °C. The anatase-to-rutile phase transformation was gradually retarded when the niobium content increased.     

Impact of side-chain length on alternating current mobility of charge carriers in regioregular poly(3-alkylthiophene) films

The charge carrier mobility in films of regioregular polythiophenes substituted by n-alkyl side-chains, of butyl, hexyl, octyl, decyl, and dodecyl, was investigated by flash-photolysis time-resolved microwave conductivity (FP-TRMC), and transient photoabsorption spectroscopy excited at 355 nm. The charge carrier concentration was estimated from inspecting radical anions of perylenecarboxydiimide (PDI), which also acts as an efficient electron acceptor to improve the yield of photocarrier generation. We discuss the dependence of side-chain length in terms of decay dynamics, quantum yield of charge carrier generation, and alternating current (ca. 9 GHz) mobility, which exceeded 0.12 cm²/(V s).     

Anderson localization and layered superconductor 2H-NbSe2−x S x

The zero-field critical temperature and the coherence length in the layered superconductor 2H-NbSe_2−x S _x (x = 0–2.0) were investigated. The zero-field critical temperature decreases with increasing the residual resistivity. This result can be explained in terms of the three-dimensional Anderson localization with the mobility edge below the Fermi level. The coherence length as a function ofx can be explained by the theory of the anisotropic three-dimensional dirty superconductor. However it shows anomalous behavior whenx = 0.6. This may be relevant to the change of the crystal structure or the disappearance of the CDW. The effective mass ratio does not depend onx whenx ≤ 0.4.     

Micro/nanostructured carbon composite modified with a hybrid redox mediator and enzymes as a glucose biosensor

A carbon micro/nanostructured composite based on cup-stacked carbon nanotubes (CSCNTs) grown onto a carbon felt has been found to be an efficient matrix for enzyme immobilization and chemical signal transduction. The obtained CSCNT/felt was modified with a copper hexacyanoferrate/polypyrrole (CuHCNFe/Ppy) hybrid mediator, and the resulting composite electrode was applied to H₂O₂ detection, achieving a sensitivity of 194 ± 15 μA mmol⁻¹ L. The results showed that the CSCNT/felt matrix significantly increased the sensitivity of CuHCNFe/Ppy-based sensors compared to those prepared on a felt unrecovered by CSCNTs. Our data revealed that the improved sensitivity of the as-prepared CuHCNFe/Ppy–CSCNT/felt composite electrode can be attributed to the electronic interactions taking place among the CuHCNFe nanocrystals, Ppy layer and CSCNTs. In addition, the presence of CSCNTs also seemed to favor the dispersion of CuHCNFe nanocrystals over the Ppy matrix, even though the CSCNTs were buried under the conducting polymer layer. The CSCNT/felt matrix also enabled the preparation of a glucose biosensor whose sensitivity could be tuned as a function of the number of glucose oxidase (GOx) layers deposited through a Layer-by-Layer technique with an sensitivity of 11 ± 2 μA mmol⁻¹ L achieved at 15 poly(diallyldimethylammoniumchloride)/GOx bilayers.     

Observation of Phase Transition from Dissolved Organic Semiconducting Materials to Solid Film during Drying

We studied the formation dynamics of low-molecular-weight organic semiconducting molecules of N,N′-bis[4-[bis(3-methylphenyl)amino]phenyl]-N,N′-diphenylbenzidine (DNTPD) during solvent evaporation. We dropped the DNTPD–toluene solution on a glass substrate and performed in situ measurements of mass, temperature, scattered light intensity, and photoluminescence (PL). We found that both light scattering and PL measurements were able to detect the onset of solid film formation from dissolved organic semiconducting materials. When a solid thin film forms during drying, sudden changes in scattered light and PL are observed. Furthermore, we also found that a period of time after the onset was necessary for completion of thin solid film formation. Observations and in situ PL measurement during thin-film formation by spin coating revealed that this period of time affected the optical properties of the film. This result indicates that quantitative information on the film formation process is quite important to obtain thin films with desired properties by coating and drying. Our in situ measurements were simple and practical approaches to monitor the formation dynamics of organic thin films during drying.