381 research outputs found
Illumination uniformity in endoscopic imaging
Standardised endoscopic digital images were taken and analysed using an image analysis software (National Instruments Vision Assistant version 7.1.1). The luminance plane was extracted and the pixel intensity distribution was determined along a horizontal line at the position of highest average intensity (centroid). The data was exported to MS Excel and the pixel intensity (y-axis) was plotted against pixel position (x-axis). A trendline using a 2nd order polynomial curve was fitted to each data set. The resultant equation for each curve was compared with equations obtained from other images taken under various illumination conditions and settings
Developments in impact damage modeling for laminated composite structures
Damage tolerance is the most critical technical issue for composite fuselage structures studied in the Advanced Technology Composite Aircraft Structures (ATCAS) program. The objective here is to understand both the impact damage resistance and residual strength of the laminated composite fuselage structure. An understanding of the different damage mechanisms which occur during an impact event will support the selection of materials and structural configurations used in different fuselage quadrants and guide the development of analysis tools for predicting the residual strength of impacted laminates. Prediction of the damage state along with the knowledge of post-impact response to applied loads will allow for engineered stacking sequencies and structural configurations; intelligent decisions on repair requirements will also result
Hydrothermal Synthesis and Characterization of One-dimensional Ceria Nanorod for Chromium Ion Removal from Wastewater
Remediation of wastewater contaminated with Cr(VI) species by ceria particles has received considerable attention in recent years. The main objectives of the present study were to investigate the adsorption of Cr(VI) species on the one-dimensional (1-D) ceria nanorod (CeNR). In where, CeNR has 20–40 nm in diameter and 200–300 nm in length, as confirmed through FE-SEM and TEM images. Higher surface area of CeNR is insisted to the remediation of Cr(VI)-contaminated wastewaters. This work exemplifies the utilization of XAS and BET to reveal the speciation of CeNR for further understands of the very complex adsorption process. It is also very clear that decontamination of Cr species in wastewater via the in-situ remediation with CeNR permeable reactive barriers would be environmentally attractive in the near future. Keywords: Cr(VI)-contaminant, One-dimensional Ceria, Wastewater treatment; XANES/EXAFS
The solar wind ionic charge states during the Ulysses pole-to-pole pass
We analyze and compare the ionic charge composition data for different types of the solar wind which the Solar Wind Ion Composition Spectrometer on Ulysses observed during the pole-to-pole pass of its primary mission. The implications on the electron temperature, electron density and ion outflow velocity from the corresponding solar wind source regions are also discussed. We find that the electron temperature in the source region of the slow solar wind is higher than that in the coronal hole. We also find a possible north-south asymmetry in the electron temperature that may be correlated to the north-south asymmetry in the solar wind speed found in the SWOOPS/Ulysses data. Based on our data without clear constraints from other coronal observations, it is found that the electron density may be higher, or the heavy ion outflow velocities may be lower toward lower heliographic latitude. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87726/2/491_1.pd
The Integration of the East and South-East Asian Equity Markets
Abstract: This study examines how the degree of capital-market integration of the East and South-East Asian (ESEA) economies varied over the period 1988–2000 following the deregulation of these markets. The deregulation process varied across the countries both in terms of intensity and timing. A greater degree of co-movements in stock prices is a reflection of greater stock-market integration. We employ Geweke’s (1982) measure of feedback for different pairs of markets. For each pair of markets, the Geweke measure shows how co-movements in daily returns of stock prices varied over time. This is followed by the vector autoregression (VAR) analysis to examine the linkages between the stock markets in the ESEA region. Therein we seek to explore whether the financial influence of Japan in the region has overtaken that of the US. A before- and after-Asian financial crisis analysis shows that the linkages and interactions among the markets have increased substantially in the postcrisis era, suggesting that the national markets have become more interdependent
Structural Change and Lead-Lag Relationship between the Nikkei Spot Index and Futures Price: A Genetic Programming Approach
Cerebral white matter disease and functional decline in older adults from the Northern Manhattan Study: A longitudinal cohort study
Background
Cerebral white matter hyperintensities (WMHs) on MRI are common and associated with vascular and functional outcomes. However, the relationship between WMHs and longitudinal trajectories of functional status is not well characterized. We hypothesized that whole brain WMHs are associated with functional decline independently of intervening clinical vascular events and other vascular risk factors.
Methods and findings
In the Northern Manhattan Study (NOMAS), a population-based racially/ethnically diverse prospective cohort study, 1,290 stroke-free individuals underwent brain MRI and were followed afterwards for a mean 7.3 years with annual functional assessments using the Barthel index (BI) (range 0–100) and vascular event surveillance. Whole brain white matter hyperintensity volume (WMHV) (as percentage of total cranial volume [TCV]) was standardized and treated continuously. Generalized estimating equation (GEE) models tested associations between whole brain WMHV and baseline BI and change in BI, adjusting for sociodemographic, vascular, and cognitive risk factors, as well as stroke and myocardial infarction (MI) occurring during follow-up. Mean age was 70.6 (standard deviation [SD] 9.0) years, 40% of participants were male, 66% Hispanic; mean whole brain WMHV was 0.68% (SD 0.84). In fully adjusted models, annual functional change was −1.04 BI points (−1.20, −0.88), with −0.74 additional points annually per SD whole brain WMHV increase from the mean (−0.99, −0.49). Whole brain WMHV was not associated with baseline BI, and results were similar for mobility and non-mobility BI domains and among those with baseline BI 95–100. A limitation of the study is the possibility of a healthy survivor bias, which would likely have underestimated the associations we found.
Conclusions
In this large population-based study, greater whole brain WMHV was associated with steeper annual decline in functional status over the long term, independently of risk factors, vascular events, and baseline functional status. Subclinical brain ischemic changes may be an independent marker of long-term functional decline
Preparation of parenteral nanocrystal suspensions of etoposide from the excipient free dry state of the drug to enhance in vivo antitumoral properties
Nanoparticle technology in cancer chemotherapy is a promising approach to enhance active ingredient pharmacology and pharmacodynamics. Indeed, drug nanoparticles display various assets such as extended blood lifespan, high drug loading and reduced cytotoxicity leading to better drug compliance. In this context, organic nanocrystal suspensions for pharmaceutical use have been developed in the past ten years. Nanocrystals offer new possibilities by combining the nanoformulation features with the properties of solid dispersed therapeutic ingredients including (i) high loading of the active ingredient, (ii) its bioavailability improvement, and (iii) reduced drug systemic cytotoxicity. However, surprisingly, no antitumoral drug has been marketed as a nanocrystal suspension until now. Etoposide, which is largely used as an anti-cancerous agent against testicular, ovarian, small cell lung, colon and breast cancer in its liquid dosage form, has been selected to develop injectable nanocrystal suspensions designed to be transferred to the clinic. The aim of the present work is to provide optimized formulations for nanostructured etoposide solutions and validate by means of in vitro and in vivo evaluations the efficiency of this multiphase system. Indeed, the etoposide formulated as a nanosuspension by a bottom-up approach showed higher blood life span, reduced tumor growth and higher tolerance in a murine carcinoma cancer model. The results obtained are promising for future clinical evaluation of these etoposide nanosuspensions
The Critical Coronal Transition Region: A Physics-framed Strategy to Uncover the Genesis of the Solar Wind and Solar Eruptions
Our current theoretical and observational understanding suggests that
critical properties of the solar wind and Coronal Mass Ejections (CMEs) are
imparted within 10 Rs, particularly below 4 Rs. This seemingly narrow spatial
region encompasses the transition of coronal plasma processes through the
entire range of physical regimes from fluid to kinetic, and from primarily
closed to open magnetic field structures. From a physics perspective,
therefore, it is more appropriate to refer to this region as the Critical
Coronal Transition Region (CCTR) to emphasize its physical, rather than
spatial, importance to key Heliophysics science.
This white paper argues that the comprehensive exploration of the CCTR will
answer two of the most central Heliophysics questions, "How and where does the
solar wind form?" and "How do eruptions form?", by unifying
hardware/software/modeling development and seemingly disparate research
communities and frameworks. We describe the outlines of decadal-scale plan to
achieve that by 2050.Comment: White paper submitted to the Decadal Survey for Solar and Space
Physics (Heliophysics) 2024-2033; 6 pages, 1 figure, 2 table
Age-related changes in eye lens biomechanics, morphology, refractive index and transparency
Life-long eye lens function requires an appropriate gradient refractive index, biomechanical integrity and transparency. We conducted an extensive study of wild-type mouse lenses 1-30 months of age to define common age-related changes. Biomechanical testing and morphometrics revealed an increase in lens volume and stiffness with age. Lens capsule thickness and peripheral fiber cell widths increased between 2 to 4 months of age but not further, and thus, cannot account for significant age-dependent increases in lens stiffness after 4 months. In lenses from mice older than 12 months, we routinely observed cataracts due to changes in cell structure, with anterior cataracts due to incomplete suture closure and a cortical ring cataract corresponding to a zone of compaction in cortical lens fiber cells. Refractive index measurements showed a rapid growth in peak refractive index between 1 to 6 months of age, and the area of highest refractive index is correlated with increases in lens nucleus size with age. These data provide a comprehensive overview of age-related changes in murine lenses, including lens size, stiffness, nuclear fraction, refractive index, transparency, capsule thickness and cell structure. Our results suggest similarities between murine and primate lenses and provide a baseline for future lens aging studies
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