The effects of colloidal nanotopography on initial fibroblast adhesion and morphology

Colloidal lithography offers a simple, inexpensive method of producing irregular nanotopographies, a pattern not easily attainable utilizing conventional serial writing processes. Colloids with 20- or 50-nm diameter were utilized to produce such an irregular topography and were characterized by calculating the percentage area coverage of particles. Interparticle and nearest neighbor spacing were also assessed for the individual colloids in the pattern. Two-way analysis of variance (ANOVA) indicated significant differences between the number of fibroblasts adhering to planar, 20-, and 50-nm-diameter colloidal topographies, the number of fibroblasts adhering to the substrates at the time intervals studied, namely 20 min, 1 h, and 3 h and significant interaction between time and topography on fibroblast adhesion (P<0.01). Tukey tests were utilized for sensitive identification of the differences between the sample means and compounded ANOVA results. Cytoskeletal and general cell morphology were investigated on planar and colloidal substrates, and indicated cells in contact with irregular nanotopographies exhibit many peripheral protrusions while such protrusions are absent in cells on planar control surfaces. These protrusions are rich in microtubules on 20-nm-diameter colloidal surfaces while microfilaments are prevalent on 50-nm-diameter surfaces. Moreover, by 3 h, cells on the colloidal substrates initiate cell-cell adhesions, also absent in controls

Lack of effect of sex on pig embryonic development in vivo

The effect of sex on pig conceptus development to day 12 of gestation was investigated. On day 2 of gestation, reciprocal embryo transfers were performed resulting in four groups (Yorkshire–Yorkshire, Yorkshire–Meishan, Meishan–Yorkshire and Meishan–Meishan). Conceptuses at day 12 were recovered from each recipient and diameter, as well as DNA, protein and oestradiol content were determined for individual conceptuses. The sex of individual conceptuses at day 12 was determined by amplification of a fragment of the pig SRY gene, using the polymerase chain reaction. Embryos developed more rapidly to day 12 in Yorkshire recipients, but there was no detectable effect of sex on the diameter, DNA, protein or oestradiol content of conceptuses from any transfer group. Thus, no sex effect was apparent under conditions either promoting or retarding the rate of early pig blastocyst growth. These results provide strong evidence that pig embryonic development occurs at a rate determined by uterine environment and not by sex of the conceptus

A global analysis of the spatial and temporal variability of usable Landsat observations at the pixel scale

The Landsat program has the longest collection of moderate-resolution satellite imagery, and the data are free to everyone. With the improvements of standardized image products, the flexibility of cloud computing platforms, and the development of time series approaches, it is now possible to conduct global-scale analyses of time series using Landsat data over multiple decades. Efforts in this regard are limited by the density of usable observations. The availability of usable Landsat Tier 1 observations at the scale of individual pixels from the perspective of time series analysis for land change monitoring is remarkably variable both in space (globally) and time (1985–2020), depending most immediately on which sensors were in operation, the technical capabilities of the mission, and the acquisition strategies and objectives of the satellite operators (e.g., USGS, commercial company) and the international ground receiving stations. Additionally, analysis of data density at the pixel scale allows for the integration of quality control data on clouds, cloud shadows, and snow as well as other properties returned from the atmospheric correction process. Maps for different time periods show the effect of excluding observations based on the presence of clouds, cloud shadows, snow, sensor saturation, hazy observations (based on atmospheric opacity), and lack of aerosol optical depth information. Two major discoveries are: 1) that filtering saturated and hazy pixels is helpful to reduce noise in the time series, although the impact may vary across different continents; 2) the atmospheric opacity band needs to be used with caution because many images are removed when no value is given in this band, when many of those observations are usable. The results provide guidance on when and where time series analysis is feasible, which will benefit many users of Landsat data.University of Connecticut; National Aeronautics and Space Administration; 80NSSC20K0022 - NASA; 20-DG-11132762-017 - Department of Agriculture/Forest Service; G12PC00070 - Department of the Interior/U.S. Geological SurveyPublished versio

Premature browning in cooked ground beef after modifying myoglobin

Some ground beef patties developed an internal, brown cooked color and looked well-done at temperatures as low as 131 ̊F, whereas normal patties were re d to pink. The premature brown color was not relate d to percent fat; patty compaction; animal source and maturity; pH (5.5 to 5.8); or concentrations of raw patty heme and nonhemeiron, myoglobin, and total pigment. Because oxidation-reduction potential and total reducing activities were higher (P<.05) and TBA numbers were lower (P<.05) in normal than prematurely brown patties, the brown color is apparently related to greater patty oxidation

The Quark-Photon Vertex and the Pion Charge Radius

The rainbow truncation of the quark Dyson-Schwinger equation is combined with the ladder Bethe-Salpeter equation for the dressed quark-photon vertex to study the low-momentum behavior of the pion electromagnetic form factor. With model gluon parameters previously fixed by the pion mass and decay constant, the pion charge radius $r_\pi$ is found to be in excellent agreement with the data. When the often-used Ball-Chiu Ansatz is used to construct the quark-photon vertex directly from the quark propagator, less than half of $r_\pi^2$ is generated. The remainder of $r^2_\pi$ is seen to be attributable to the presence of the $\rho$-pole in the solution of the ladder Bethe-Salpeter equation.Comment: 21 pages, 9 figure

China Earthquake Reconnaissance Report: Performance of Transportation Structures during the May 12, 2008, M7.9 Wenchuan Earthquake

This report documents the lessons learned from damage caused in the May 12, 2008, M7.9 earthquake in Wenchuan County, China. The damage to the 14 observed bridges reminded the researchers of damage suffered during the 1971 San Fernando Earthquake in California. The bridges had few seismic details such as long seats, large shear keys, or tightly spaced transverse reinforcement. Most arch and girder bridges collapsed due to surface rupturing of the seismic faults in the Longmen-Shan thrust zone. A significant portion of roadways and bridges were pushed away or buried by landslides in the steep slopes of mountainous terrain. Damage to bridge superstructure included unseating of girders, longitudinal and transverse offset of decks, pounding at expansion joints, and shear key failure. The bearings of several girder bridges were either crushed or displaced significantly. The substructure and foundation of bridges were subjected to shear and flexural cracks, concrete spalling, stirrup rupture, excessive displacement, and loss of stability. More damage occurred in simply supported bridges than in continuous spans. Curved bridges either collapsed or suffered severe damage. Evidence of directivity effects on bridges near the earthquake epicenter was observed during the earthquake. The San Fernando earthquake significantly changed the seismic design and construction of bridges in the United States. The Wenchuan earthquake is expected to have the same significance for China\u27s bridge engineers

Holographic approach to a minimal Higgsless model

In this work, following an holographic approach, we carry out a low energy effective study of a minimal Higgsless model based on SU(2) bulk symmetry broken by boundary conditions, both in flat and warped metric. The holographic procedure turns out to be an useful computation technique to achieve an effective four dimensional formulation of the model taking into account the corrections coming from the extra dimensional sector. This technique is used to compute both oblique and direct contributions to the electroweak parameters in presence of fermions delocalized along the fifth dimension.Comment: Latex file, 23 page