Interaction of Colloidal Particles with Surfaces of Biological Significance

The adhesion of colloidal gold on membranes was examined with an electron microscope with protein on the membrane, on the colloidal particles and present on both membrane and particles. The conditions for best adhesion were determined. Quantitative measurements were caNied out using adhesion to the membrane to monitor diffusion, centrifugation and electrophoresis of colloidal particles. Electrophoresis in a centrifugal field was used as a nul method to determine the charge on the colloidal particle

Sheathless Size-Based Acoustic Particle Separation

Particle separation is of great interest in many biological and biomedical applications. Flow-based methods have been used to sort particles and cells. However, the main challenge with flow based particle separation systems is the need for a sheath flow for successful operation. Existence of the sheath liquid dilutes the analyte, necessitates precise flow control between sample and sheath flow, requires a complicated design to create sheath flow and separation efficiency depends on the sheath liquid composition. In this paper, we present a microfluidic platform for sheathless particle separation using standing surface acoustic waves. In this platform, particles are first lined up at the center of the channel without introducing any external sheath flow. The particles are then entered into the second stage where particles are driven towards the off-center pressure nodes for size based separation. The larger particles are exposed to more lateral displacement in the channel due to the acoustic force differences. Consequently, different-size particles are separated into multiple collection outlets. The prominent feature of the present microfluidic platform is that the device does not require the use of the sheath flow for positioning and aligning of particles. Instead, the sheathless flow focusing and separation are integrated within a single microfluidic device and accomplished simultaneously. In this paper, we demonstrated two different particle size-resolution separations; (1) 3 µm and 10 µm and (2) 3 µm and 5 µm. Also, the effects of the input power, the flow rate, and particle concentration on the separation efficiency were investigated. These technologies have potential to impact broadly various areas including the essential microfluidic components for lab-on-a-chip system and integrated biological and biomedical applications.Bankhead-Coley Florida Cancer Research Program (Grant # 1BN04-34183)National Science Foundation (U.S.) (Grant 0968736)National Science Foundation (U.S.) (Grant 1135419)National Science Foundation (U.S.) (Grant 1056475

On the seismic analysis and design of offshore wind turbines

Offshore wind farms are a collection of offshore wind turbines (OWTs) and are currently being installed in seismically active regions. An OWT consists of a long slender tower with a top-heavy fixed mass (Nacelle) together with a heavy rotating mass (Hub and blades) and is always exposed to variable environmental wind and wave loads. For dynamic analysis, an OWT can also be seen as an inverted pendulum (with over 25%–50% of the total mass concentrated in the upper 3rd of the tower), yet it is not granted that their seismic response is dominated by the first mode. Guidelines for the design of such special structures are not explicitly mentioned in current codes of practice. The aim of this technical note is to identify the design issues and provide a rational background for the seismic analysis. Where feasible, further research work that is needed is also identified and discussed.•Considerations for seismic design.•Design return period.•Types of seismic analysis.•Selection of input motion

Genetic contribution of SCARB1 variants to lipid traits in African Blacks: A candidate gene association study

Background: High-density lipoprotein cholesterol (HDL-C) exerts many anti-atherogenic properties including its role in reverse cholesterol transport (RCT). Scavenger receptor class B member 1 (SCARB1) plays a key role in RCT by selective uptake of HDL cholesteryl esters. We aimed to explore the genetic contribution of SCARB1 to affecting lipid levels in African Blacks from Nigeria. Methods: We resequenced 13 exons and exon-intron boundaries of SCARB1 in 95 individuals with extreme HDL-C levels using Sanger method. Then, we genotyped 147 selected variants (78 sequence variants, 69 HapMap tagSNPs, and 2 previously reported relevant variants) in the entire sample of 788 African Blacks using either the iPLEX Gold or TaqMan methods. A total of 137 successfully genotyped variants were further evaluated for association with major lipid traits. Results: The initial gene-based analysis demonstrated evidence of association with HDL-C and apolipoprotein A-I (ApoA-I). The follow-up single-site analysis revealed nominal evidence of novel associations of nine common variants with HDL-C and/or ApoA-I (P < 0.05). The strongest association was between rs11057851 and HDL-C (P = 0.0043), which remained significant after controlling for multiple testing using false discovery rate. Rare variant association testing revealed a group of 23 rare variants (frequencies ≤1 %) associated with HDL-C (P = 0.0478). Haplotype analysis identified four SCARB1 regions associated with HDL-C (global P < 0.05). Conclusions: To our knowledge, this is the first report of a comprehensive association study of SCARB1 variations with lipid traits in an African Black population. Our results showed the consistent association of SCARB1 variants with HDL-C across various association analyses, supporting the role of SCARB1 in lipoprotein-lipid regulatory mechanism

Drexel University

We present a 3D matching framework based on a many-to-many matching algorithm that works with skeletal representations of 3D volumetric objects. We demonstrate the performance of this approach on a large database of 3D objects containing more than 1000 exemplars. The method is especially suited to matching objects with distinct part structure and is invariant to part articulation. Skeletal matching has an intuitive quality that helps in defining the search and visualizing the results. In particular, the matching algorithm produces a direct correspondence between two skeletons and their parts, which can be used for registration and juxtaposition. 1

Housing insecurity, housing conditions, and breastfeeding behaviors for medicaid-eligible families in urban settings

BACKGROUND: Research exploring associations between exposure to social determinants of health and breastfeeding is needed to identify breastfeeding barriers. Housing insecurity and household conditions (chaos and crowding) may affect breastfeeding by increasing maternal stress and discomfort and decreasing time available to breastfeed. RESEARCH AIM: We aimed to examine the relationships between housing insecurity, breastfeeding exclusivity intention during the early postnatal period, and breastfeeding exclusivity at 6 months postpartum among a sample "at risk" for suboptimal breastfeeding rates. METHODS: This study is a secondary data analysis of a longitudinal study at two time periods. Data were collected from English- and Spanish-speaking, Medicaid-eligible mother-infant dyads (N = 361) at near-birth and child aged 6 months, in New York City and Pittsburgh. Structural equation modeling was used to examine direct and indirect effects of housing insecurity on breastfeeding exclusivity at child aged 6 months. RESULTS: The path model showed that experiencing more markers of housing insecurity (i.e., foreclosure/eviction threat, history of homelessness, late rent) was predictive of significantly lower breastfeeding exclusivity at 6 months. This was partially mediated through less exclusive breastfeeding intention during the early postnatal period. Greater household crowding was associated with 6-month breastfeeding exclusivity when mediated by intention. Household crowding had differential effects by study site and participant race/ethnicity. CONCLUSION: Refinement of housing insecurity as a multi-dimensional construct can lead to the development of standardized data collection instruments, inform future methodological decisions in research addressing social determinants of health, and can inform the development of responsive individual- and structural-level interventions.The data used in this study were collected as part of the SMART Beginnings Randomized Controlled Trial (NCT02459327 registered at ClinicalTrials.gov)