2,091 research outputs found
Commercial Applications Multispectral Sensor System
NASA's Office of Commercial Programs is funding a multispectral sensor system to be used in the development of remote sensing applications. The Airborne Terrestrial Applications Sensor (ATLAS) is designed to provide versatility in acquiring spectral and spatial information. The ATLAS system will be a test bed for the development of specifications for airborne and spaceborne remote sensing instrumentation for dedicated applications. This objective requires spectral coverage from the visible through thermal infrared wavelengths, variable spatial resolution from 2-25 meters; high geometric and geo-location accuracy; on-board radiometric calibration; digital recording; and optimized performance for minimized cost, size, and weight. ATLAS is scheduled to be available in 3rd quarter 1992 for acquisition of data for applications such as environmental monitoring, facilities management, geographic information systems data base development, and mineral exploration
Tendon proper- and peritenon-derived progenitor cells have unique tenogenic properties.
IntroductionMultipotent progenitor populations exist within the tendon proper and peritenon of the Achilles tendon. Progenitor populations derived from the tendon proper and peritenon are enriched with distinct cell types that are distinguished by expression of markers of tendon and vascular or pericyte origins, respectively. The objective of this study was to discern the unique tenogenic properties of tendon proper- and peritenon-derived progenitors within an in vitro model. We hypothesized that progenitors from each region contribute differently to tendon formation; thus, when incorporated into a regenerative model, progenitors from each region will respond uniquely. Moreover, we hypothesized that cell populations like progenitors were capable of stimulating tenogenic differentiation, so we generated conditioned media from these cell types to analyze their stimulatory potentials.MethodsIsolated progenitors were seeded within fibrinogen/thrombin gel-based constructs with or without supplementation with recombinant growth/differentiation factor-5 (GDF5). Early and late in culture, gene expression of differentiation markers and matrix assembly genes was analyzed. Tendon construct ultrastructure was also compared after 45 days. Moreover, conditioned media from tendon proper-derived progenitors, peritenon-derived progenitors, or tenocytes was applied to each of the three cell types to determine paracrine stimulatory effects of the factors secreted from each of the respective cell types.ResultsThe cell orientation, extracellular domain and fibril organization of constructs were comparable to embryonic tendon. The tendon proper-derived progenitors produced a more tendon-like construct than the peritenon-derived progenitors. Seeded tendon proper-derived progenitors expressed greater levels of tenogenic markers and matrix assembly genes, relative to peritenon-derived progenitors. However, GDF5 supplementation improved expression of matrix assembly genes in peritenon progenitors and structurally led to increased mean fibril diameters. It also was found that peritenon-derived progenitors secrete factor(s) stimulatory to tenocytes and tendon proper progenitors.ConclusionsData demonstrate that, relative to peritenon-derived progenitors, tendon proper progenitors have greater potential for forming functional tendon-like tissue. Furthermore, factors secreted by peritenon-derived progenitors suggest a trophic role for this cell type as well. Thus, these findings highlight the synergistic potential of including these progenitor populations in restorative tendon engineering strategies
Nanometer lithography on silicon and hydrogenated amorphous silicon with low-energy electrons
We report the local oxidation of hydrogen terminated silicon (Si) surfaces induced with the scanning-tunneling microscope (STM) operating in air and by a beam of free low-energy electrons. With STM, oxide lines were written in Si(100) and Si(110) and transferred into the substrate by wet etching. In case of Si(110) trenches with a width as small as 35 nm and a depth of 300 nm were made. The same process has also successfully been applied to the patterning of hydrogenated amorphous silicon (a-Si:H) thin films. We demonstrate the fabrication of metallic ‘nanowires’ using a-Si:H as resist layer. With regard to the process of oxidation, it is found that the oxide written with STM is apparently not proportional to the electron current, in contrast to results obtained with a beam of free electrons in an oxygen gas-environment. The dose needed to remove the hydrogen was determined as a function of electron energy. This dose is minimal for 100 eV electrons amounting to 4 mC/cm2
Engaging Students by Developing Patterns from a Historic Garment
Apparel construction courses provide opportunity for hands-on activities (McKeatchie, Pintrich, Lin, & Smith, 1987) and using a historic costume collection. Hands-on learning activities in apparel construction courses that incorporated history of costume has been found to enhance students\u27 critical thinking and analysis of skills (Banard, 2015). These skills are valuable in the fashion industry (Banard; Weaver, 2011). A hands-on teaching assignment was developed in which a flat pattern class made patterns from historic garments to prepare for the digitizing process and the proposed steps in product development. Purpose/Objective of Strategy The purpose/objective of this teaching strategy was to: 1. apply flat pattern skills to replicate a historic garment, 2. record the measurements needed to successfully replicate a historic garment, 3. critically evaluate patterns made from a historic garment, 4. demonstrate how to manipulate pattern pieces to create style lines or shape into garments via flat pattern methods, and 5. translate a design idea into a flat pattern. This class will be implemented in the curriculum
Introduction to Remote Sensing: Science for Society
Science for Society: Extending Earth Science Research Results into Decision Support Tool
Faecal Steroids and n-Alkanes in Lake Sediments
Lake sediments are used as archives for climate and environmental reconstructions. This study investigated if biomarker analyses in lake sediments can be used to reconstruct anthropogenic landscape modifications during Holocene. In contrast to the mineral matrix of sediments and e.g. pollen, plant macro remains and charcoal particles, biomarkers can be more easily translocated within soil profiles before erosion and deposition. Furthermore, a translocation can also occur in lake sediments. Therefore, we tested if biomarker concentrations and patterns correlated with pollen patterns and further paleo environmental proxies in sediments of two maar lakes in the Eifel region. Five core sections of Lake Holzmaar and two core sections of Lake Ulmener Maar were sampled. The analysed core sections contain ca. 10 000 years and a number of data existed from previous analyses (ELSA project). As example for biomarkers for the reconstruction of vegetation changes, n-alkanes were analysed. Steroids incl. bile acids were used as proxies for the deposition of faeces of animals (animal husbandry). Patterns of n-alkanes correlated with pollen data. Parts of the core that show characteristics of dense forest in the catchment area had relatively low amounts of faecal steroids and the steroid patterns indicated the presence of several different animals. In parts of the core that show characteristics for grassland and agricultural fields, faecal steroids showed the presence of animal husbandry. The correlation of biomarker concentrations with pollen data and other data showed that it possible to detect changes in vegetation and land use with biomarker analyses within the catchment area of the two maar lakes
Cornea organoids from human induced pluripotent stem cells.
The cornea is the transparent outermost surface of the eye, consisting of a stratified epithelium, a collagenous stroma and an innermost single-cell layered endothelium and providing 2/3 of the refractive power of the eye. Multiple diseases of the cornea arise from genetic defects where the ultimate phenotype can be influenced by cross talk between the cell types and the extracellular matrix. Cell culture modeling of diseases can benefit from cornea organoids that include multiple corneal cell types and extracellular matrices. Here we present human iPS cell-derived organoids through sequential rounds of differentiation programs. These organoids share features of the developing cornea, harboring three distinct cell types with expression of key epithelial, stromal and endothelial cell markers. Cornea organoid cultures provide a powerful 3D model system for investigating corneal developmental processes and their disruptions in diseased conditions
- …