Study of effects of space power satellites on life support functions of the earth's magnetosphere

The effects of the Satellite Solar Power System (SSPS) on the life support functions of the earth's magnetosphere were investigated. Topics considered include: (1) thruster effluent effects on the magnetosphere; (2) biological consequences of SSPS reflected light; (3) impact on earth bound astronomy; (4) catastrophic failure and debris; (5) satellite induced processes; and (6) microwave power transmission. Several impacts are identified and recommendations for further studies are provided

Practice Models and Challenges in Teledermatology: A Study of Collective Experiences from Teledermatologists

Despite increasing practice of teledermatology in the U.S., teledermatology practice models and real-world challenges are rarely studied.The primary objective was to examine teledermatology practice models and shared challenges among teledermatologists in California, focusing on practice operations, reimbursement considerations, barriers to sustainability, and incentives. We conducted in-depth interviews with teledermatologists that practiced store-and-forward or live-interactive teledermatology from January 1, 2007 through March 30, 2011 in California.Seventeen teledermatologists from academia, private practice, health maintenance organizations, and county settings participated in the study. Among them, 76% practiced store-and-forward only, 6% practiced live-interactive only, and 18% practiced both modalities. Only 29% received structured training in teledermatology. The average number of years practicing teledermatology was 4.29 years (SD±2.81). Approximately 47% of teledermatologists served at least one Federally Qualified Health Center. Over 75% of patients seen via teledermatology were at or below 200% federal poverty level and usually lived in rural regions without dermatologist access. Practice challenges were identified in the following areas. Teledermatologists faced delays in reimbursements and non-reimbursement of teledermatology services. The primary reason for operational inefficiency was poor image quality and/or inadequate history. Costly and inefficient software platforms and lack of communication with referring providers also presented barriers.Teledermatology enables underserved populations to access specialty care. Improvements in reimbursement mechanisms, efficient technology platforms, communication with referring providers, and teledermatology training are necessary to support sustainable practices

Pancreatic Duct Glands Are Distinct Ductal Compartments That React to Chronic Injury and Mediate Shh-Induced Metaplasia

BACKGROUND & AIMS: Pancreatic intraepithelial neoplasia (PanIN) are pancreatic cancer precursor lesions of unclear origin and significance. PanIN aberrantly express sonic hedgehog (Shh), an initiator of pancreatic cancer, and gastrointestinal mucins. A majority of PanIN are thought to arise from ducts. We identified a novel ductal compartment that is gathered in gland-like outpouches (pancreatic duct glands [PDG]) of major ducts and characterized its role in injury and metaplasia. METHODS: The ductal system was analyzed in normal pancreata and chronic pancreatitis in humans and mice. Anatomy was assessed by serial hematoxylin and eosin sections and scanning electron microscopy of corrosion casts. Expression of mucins and developmental genes and proliferation were assessed by immunohistochemistry or real-time quantitative polymerase chain reaction. Effects of Shh on ductal cells were investigated by exposure to Shh in vitro and transgenic misexpression in vivo. RESULTS: Three-dimensional analysis revealed blind-ending outpouches of ducts in murine and human pancreata. These PDG are morphologically and molecularly distinct from normal ducts; even in normal pancreata they display PanIN and metaplastic features, such as expression of Shh and gastric mucins. They express other developmental genes, such as Pdx-1 and Hes-1. In injury, Shh is up-regulated along with gastric mucins. Expansion of the PDG compartment results in a mucinous metaplasia. Shh promotes this transformation in vitro and in vivo. CONCLUSIONS: PDG are distinct gland-like mucinous compartments with a distinct molecular signature. In response to injury, PDG undergo an Shh-mediated mucinous gastrointestinal metaplasia with PanIN-like features. PDG may provide a link between Shh, mucinous metaplasia, and neoplasia

A Methodology for Successful University Graduate CubeSat Programs

The University of Colorado Smead Department of Aerospace Engineering has over a decade of success in designing, building, and operating student led CubeSat missions. The experience and lessons learned from building and operating the CSSWE, MinXSS-1, MinXSS-2, and QB50-Challenger missions have helped grow a knowledge base on the most effective and efficient ways to manage some of the “tall poles” when it comes to student run CubeSat missions. Among these “tall poles” we have seen student turnover, software, and documentation become some of the hardest to knock-down and we present our strategies for doing so. We use the MAXWELL mission (expected to launch in 2021) as a road-map to detail the methodology we have built over the last decade to ensure the greatest chance of mission success

MicroRNAs targeting oncogenes are down-regulated in pancreatic malignant transformation from benign tumors

BACKGROUND MicroRNA (miRNA) expression profiles have been described in pancreatic ductal adenocarcinoma (PDAC), but these have not been compared with pre-malignant pancreatic tumors. We wished to compare the miRNA expression signatures in pancreatic benign cystic tumors (BCT) of low and high malignant potential with PDAC, in order to identify miRNAs deregulated during PDAC development. The mechanistic consequences of miRNA dysregulation were further evaluated. METHODS Tissue samples were obtained at a tertiary pancreatic unit from individuals with BCT and PDAC. MiRNA profiling was performed using a custom microarray and results were validated using RT-qPCR prior to evaluation of miRNA targets. RESULTS Widespread miRNA down-regulation was observed in PDAC compared to low malignant potential BCT. We show that amongst those miRNAs down-regulated, miR-16, miR-126 and let-7d regulate known PDAC oncogenes (targeting BCL2, CRK and KRAS respectively). Notably, miR-126 also directly targets the KRAS transcript at a "seedless" binding site within its 3'UTR. In clinical specimens, miR-126 was strongly down-regulated in PDAC tissues, with an associated elevation in KRAS and CRK proteins. Furthermore, miR-21, a known oncogenic miRNA in pancreatic and other cancers, was not elevated in PDAC compared to serous microcystic adenoma (SMCA), but in both groups it was up-regulated compared to normal pancreas, implicating early up-regulation during malignant change. CONCLUSIONS Expression profiling revealed 21 miRNAs down-regulated in PDAC compared to SMCA, the most benign lesion that rarely progresses to invasive carcinoma. It appears that miR-21 up-regulation is an early event in the transformation from normal pancreatic tissue. MiRNA expression has the potential to distinguish PDAC from normal pancreas and BCT. Mechanistically the down-regulation of miR-16, miR-126 and let-7d promotes PDAC transformation by post-transcriptional up-regulation of crucial PDAC oncogenes. We show that miR-126 is able to directly target KRAS; re-expression has the potential as a therapeutic strategy against PDAC and other KRAS-driven cancers

Twirling of actin by myosins II and V observed via polarized TIRF in a modified gliding assay

The force generated between actin and myosin acts predominantly along the direction of the actin filament, resulting in relative sliding of the thick and thin filaments in muscle or transport of myosin cargos along actin tracks. Previous studies have also detected lateral forces or torques that are generated between actin and myosin, but the origin and biological role of these sideways forces is not known. Here we adapt an actin gliding filament assay in order to measure the rotation of an actin filament about its axis (twirling) as it is translocated by myosin. We quantify the rotation by determining the orientation of sparsely incorporated rhodamine-labeled actin monomers, using polarized total internal reflection (polTIRF) microscopy. In order to determine the handedness of the filament rotation, linear incident polarizations in between the standard s- and p-polarizations were generated, decreasing the ambiguity of our probe orientation measurement four-fold. We found that whole myosin II and myosin V both twirl actin with a relatively long (micron), left-handed pitch that is insensitive to myosin concentration, filament length and filament velocity

The length dependence of the series elasticity of pig bladder smooth muscle

Strips of urinary bladder smooth muscle were subjected to a series of quick release measurements. Each measurement consisted of several releases and resets to the original length, made during one contraction. The complete length-force characteristic of series elasticity was quantified by estimating H, the amplitude of quick release necessary to reduce the active force to exactly zero, and Db, a measure for the deviation of the characteristic from a straight line. By measuring a series of contractions at increasing stretched strip lengths, the length dependence of these parameters was studied. It was found that H depends linearly on stretched strip length. On average H/length amounted to 0.04. Db decreased when strips were stretched, i.e. a straight line was more closely approximated. Both parameter dependencies support the concept of two separate elastic mechanisms, a linear true passive elasticity in series with a non-linear elasticity in the cross-bridges. For the latter, H amounts to 3.8% of the initial strip length

Deformation and Grain Growth of Low-Temperature-Sintered High-Purity Alumina

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66091/1/j.1151-2916.1990.tb06489.x.pd