In vitro skin permeation and cellular protective effects of flavonoids isolated from Suaeda asparagoides extracts

The objective of this study was to compare astragalin (kaempferol-3-O-glucoside) isolated from Suaeda asparagoides extract with kaempferol, an aglycone of astragalin showing the anti-oxidative activity, the cellular protective effect, and skin permeability. Kaempferol was superior to (+)-α-tocopherol and l-ascorbic acid known as strong antioxidants in the antioxidative activity by DPPH method and chemiluminescence assay. Astragalin and kaempferol exhibited more prominent cellular protective effect than the lipid peroxidation chain blocker, (+)-α-tocopherol. In this in vitro permeation experiment of astragalin and kaempferol through the ICR mouse skin, kaempferol permeated deeper into the skin than astragalin. These results indicate that kaempferol and astragalin can function as antioxidants in biological systems, particularly skin exposed to solar radiation, and protect cellular membranes against reactive oxygen species.     

Development of a tomographic PTV

A new tomographic PTV (Tomo-PTV) was proposed, and then its performance was compared with that of tomographic PIV (Tomo-PIV). To construct the new tomographic PTV for calculation of vector fields, an affine transformation was introduced. The vectors obtained by match probability method were used as the initial data for the final vectors. Four camera-based tomographic PTV and PIV systems were constructed. By introducing a new factor called degree of reality, the real particles were easily separated from the ghost particle groups. Two flow fields, a ring vortex and an impinging jet, were measured by the constructed tomographic PTV and the conventional tomographic PIV. Eight image frames (two consecutive image frames for each camera) were used for the construction of threedimensional voxel images. The construction method used for the voxel images was MLOS-MART.     

The Role of Aluminum in the Detonation and Post‐Detonation Expansion of Selected Cast HMX‐Based Explosives

In order to improve understanding of how aluminum contributes in non‐ideal explosive mixtures, cast‐cured formulations have been analyzed in a series of cylinder tests and plate‐pushing experiments. This study describes the contribution of 15 % aluminum (median size of 3.2 μm) vs. lithium fluoride (an inert substitute for aluminum; <5 μm) in cast‐cured HMX formulations in different temporal regimes. Small cylinder tests were performed to analyze the detonation and wall velocities (1–20 μs) for these formulations. Near‐field blast effects of 58 mm diameter spherical charges were measured at 152 mm and 254 mm using steel plate acceleration. Pressure measurements at 1.52 m gave information about free‐field pressure at several milliseconds. While the observed detonation velocities for all formulations were within uncertainty, significantly higher cylinder wall velocities, plate velocities, and pressures were observed for the aluminum formulations at ≥2 μs. Additionally, hydrocode calculations were performed to determine how non‐ideal behavior affected the plate test results. Collectively, this work gives a clearer picture of how aluminum contributes to detonation on timescales from 1 μs to about 2 ms, and how the post‐detonation energy release contributes to wall velocities and blast effects. The experiments indicate that significant aluminum reactions occur after the CJ plane, and continue to contribute to expansion at late times.     

Identifying FMRI model violations with lagrange multiplier tests

The standard modeling framework in functional magnetic resonance imaging (fMRI) is predicated on assumptions of linearity, time invariance and stationarity. These assumptions are rarely checked because doing so requires specialized software, although failure to do so can lead to bias and mistaken inference. Identifying model violations is an essential but largely neglected step in standard fMRI data analysis. Using Lagrange multiplier testing methods we have developed simple and efficient procedures for detecting model violations such as nonlinearity, nonstationarity and validity of the common double gamma specification for hemodynamic response. These procedures are computationally cheap and can easily be added to a conventional analysis. The test statistic is calculated at each voxel and displayed as a spatial anomaly map which shows regions where a model is violated. The methodology is illustrated with a large number of real data examples.     

Octupolar Films with Large Second Harmonic Generation and Electro‐Optical Effects

Thin films that benefit from efficient octupolar molecular packing are prepared for second harmonic generation (SHG) and electro‐optic (EO) applications. The films are composed of 1,3,5‐tricyano‐2, 4,6‐tris(p‐diethylaminostyryl)benzene (TTB) in a ploymethylmetacrylate (PMMA) matrix on aluminum/BK7 glass (Al/BK7) and polyimide/indium tin oxide (PI/ITO) substrates. Octupolar films prepared on both substrates display polycrystalline and cylindrical domains. The molecular orientation, SHG efficiencies, and EO coefficients of the crystalline domains are measured. In the cylinders, the molecular crystal planes are oriented perpendicularly to the major cylinder axis, whereas in the polycrystals, the planes are randomly oriented. While both structures exhibit high and stable SHG and EO efficiencies, the cylinders, in particular, exhibited a very large SHG, a large EO coefficient, and high thermal stability; these characteristics will be useful in second order nonlinear optical applications.     

Evaluation of electromagnetic loads on various design options of the ITER diagnostic upper port plug during plasma disruptions

Electromagnetic (EM) loads due to eddy current and halo current during plasma disruptions are evaluated for the ITER diagnostic upper port plug. To reduce strong EM loads acting on the port plug fixed to the vacuum vessel like a cantilever beam, three design options have been considered: removal of the diagnostic first wall, slitting of the diagnostic shield module and recess of the port plug. The main focus of the present study is to examine the efficacy of these options in terms of EM loads on the upper port plug. It is found that making slits is more effective than removing the first wall. It is also shown that the upper port plug needs to be recessed to reduce the EM load induced by halo current.     

Stretching‐Induced Growth of PEDOT‐Rich Cores: A New Mechanism for Strain‐Dependent Resistivity Change in PEDOT:PSS Films

It remains a fundamental challenge in the development of stretchable electronics to understand how mechanical strain changes the electrical properties of materials. Although the piezoresistive behavior of poly(3,4‐ethylene‐ dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been observed, its intrinsic origin is not yet fully understood because there are many extrinsic contributing factors and an experimental platform with which to assess such behavior has not been established. Here, systematic analysis shows that the matching Poisson's ratio and elastic modulus between PEDOT:PSS films and their underlying substrates is important in decoupling the factors that affect the material's piezoresistivity, allowing for tunable resistivity. Based on such a fundamental understanding, the conductivity of PEDOT:PSS can be controlled to be invariant and decrease as a function of applied tensile stress. Furthermore, a linear response of the resistivity with respect to mechanical strains of up to 60%, which has never before been realized, is shown. The irreversible conductivity enhancement is primarily caused by the coalescence‐induced growth of conductive PEDOT‐rich cores.     

Optical Properties and Associated Hygroscopicity of Clay Aerosols

Airborne mineral dust particles contribute a significant fraction to the total aerosol mass, thus they make a substantial contribution to the Earth's radiative budget by direct scattering and absorption of radiation. Quantifying their contribution is complicated by the variability of optical properties as a function of water uptake. To improve understanding, we directly measured the relative humidity (RH) dependence of extinction [fRH_ext(RH, Dry)] for three key silicate clay components (illite, kaolinite, and montmorillonite) of mineral dust aerosols through cavity ring-down spectroscopy at 532 nm. The three clays studied show significant differences in fRH_ext(RH, Dry) at three RH values, and reasons for this are explored. With 68% RH as an example, we used the fRH_ext(RH, Dry) and Mie theory to calculate a growth factor for comparison with other measurement techniques. Humidified tandem differential mobility analyzer and quartz crystal microbalance growth factors from the literature are larger than our optical measurements indicate. An apparent decrease in particle size calculated from optical measurements for illite and kaolinite was further investigated by determining the aerosol electrical mobility size distribution of 68% RH and dry clay particles at that indicated shrinkage of approximately 10% at elevated humidity. Direct optical measurement has advantages because the effects of irregular shape and internal voids are observed. Our calculated growth factors provide a lower limit and can be incorporated into climate models in conjunction with other results to reduce the uncertainty associated with the optical response to water uptake on clay aerosols.     

Properties of molecular composite film of poly(4,4'-diamino-2'-carbamoylbenzanilide terephthalamide)(p-PDCBTA) and poly(4,4'-diamino-2'-chlorobenzanilide terephthalamide) (P-LCI)

Summary A new thermally stable, high strength and high modulus aromatic polyamide film was obtained via the formation of the molecular composite of p-PDCBTA and P-LCl. The two polymers exhibited good miscibility identified with the measurement of dynamic mechanical property and FTIR spectra. By the combination of drawing by 40% and subsequent heat treatment, the tensile property of the composite film could be achieved to the strength of 450 MPa and the modulus of 24 GPa, which were sustainable upto 400 °C. Received: 31 August 1999/Revised version: 19 November 1999/Accepted: 25 November 1999