1,290 research outputs found
Tension measurement device Patent
Apparatus for measuring load on cable under static or dynamic conditions comprising pulleys pivoting structure against restraint of tension stra
Improved control system power unit for large parachutes
Improved control system power unit drives the control surfaces of very large controllable parachutes. The design features subassemblies for determining control surface position and cable loading, and protection of the load sensor against the possibility of damage during manipulation
Line cutter Patent
Piston in bore cutter for severing parachute control lines and sealing cable hole to prevent water leakage into loa
Winch having cable position and load indicators Patent
Design and characteristics of device for showing amount of cable payed out from winch and load impose
Discrete local altitude sensing device Patent
Device for use in descending spacecraft as altitude sensor for actuating deceleration retrorocket
Probing the C-H Activation of Linear and Cyclic Ethers at (PNP)Ir
Interaction of the amido/bis(phosphine)-supported (PNP)Ir fragment with a series of linear and cyclic ethers is shown to afford, depending on substrate, products of α,α-dehydrogenation (carbenes), α,β-dehydrogenation (vinyl ethers), or decarbonylation. While carbenes are exclusively obtained from tert-amyl methyl ether, sec-butyl methyl ether (SBME), n-butyl methyl ether (NBME), and tetrahydrofuran (THF), vinyl ethers or their adducts are observed upon reaction with diethyl ether and 1,4-dioxane. Decarbonylation occurs upon interaction of (PNP)Ir with benzyl methyl ether, and a mechanism is proposed for this unusual transformation, which occurs via a series of C−H, C−O, and C−C bond cleavage events. The intermediates characterized for several of these reactions as well as the α,α-dehydrogenation of tert-butyl methyl ether (MTBE) are used to outline a reaction pathway for the generation of PNP-supported iridium(I) carbene complexes, and it is shown that the long-lived, observable intermediates are substrate-dependent and differ for the related cases of MTBE and THF. Taken together, these findings highlight the variety of pathways utilized by the electron-rich, unsaturated (PNP)Ir fragment to stabilize itself by transferring electron density to ethereal substrates through oxidative addition and/or the formation of π-acidic ligands
An Exploratory Study of Aquatic Walking on Symptoms and Functional Limitations in Persons with Knee Osteoarthritis: Part 1
This paper represents Part 1 of a study that explored the effects of an underwater treadmill (UT) walking program on pain and function in adults with knee osteoarthritis (KOA). The Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC), numerical rating scale (NRS), timed up-and-go (TUG), and 10-m walk were assessed in 6 adults (62.7 ±14.2 years) who participated in an 8-week (3x/wk) UT walking intervention based on the Arthritis Foundation’s Walk With Ease (WWE) program. Walking pace was self-selected, and walking duration of each session was increased from 10 to 45 minutes throughout the study. Knee pain and function were assessed pre-control (PRC), pre-intervention (PRI) and post-intervention (PST). NRS improved from PRC and PRI to PST (p = .03, d = .37). WOMAC subscale scores of pain, (d = .36); stiffness (d = .44); pain during daily activities (d = .41); and total scores (d = .42) improved (p \u3c .05) from PRC to PST. Self-selected walking speed increased concurrently with decreased knee pain (NRS) from PRI to PST. The results support the WWE as a model for an UT walking program for improving knee pain in KOA
Core-Clickable PEG-Branch-Azide Bivalent-Bottle-Brush Polymers by ROMP: Grafting-Through and Clicking-To
The combination of highly efficient polymerizations with modular "click" coupling reactions has enabled the synthesis of a wide variety of novel nanoscopic tructures. Here we demonstrate the facile synthesis of a new class of clickable, branched nanostructures, polyethylene glycol (PEG)-branch-azide bivalent-brush polymers, facilitated by "graft-through" ring-opening metathesis polymerization of a branched norbornene-PEG-chloride macromonomer followed by halide-azide exchange. The resulting bivalent-brush polymers possess azide groups at the core near a polynorbornene backbone with PEG chains extended into solution; the structure resembles a unimolecular micelle. We demonstrate copper-catalyzed azide-alkre cycloaddition (CuAAC) "click-to" coupling of a photocleavable doxorubicin (DOX)-alkyne derivative to the azide core. The CuAAC coupling was quantitative across a wide range of nanoscopic sizes (similar to 6-similar to 50 nrn); UV photolysis of the resulting DOX-loaded materials yielded free DOX that was therapeutically effective against human cancer cells
Recent Advancements in Stereoselective Olefin Metathesis Using Ruthenium Catalysts
Olefin metathesis is a prevailing method for the construction of organic molecules. Recent advancements in olefin metathesis have focused on stereoselective transformations. Ruthenium olefin metathesis catalysts have had a particularly pronounced impact in the area of stereoselective olefin metathesis. The development of three categories of Z-selective olefin metathesis catalysts has made Z-olefins easily accessible to both laboratory and industrial chemists. Further design enhancements to asymmetric olefin metathesis catalysts have streamlined the construction of complex molecules. The understanding gained in these areas has extended to the employment of ruthenium catalysts to stereoretentive olefin metathesis, the first example of a kinetically E-selective process. These advancements, as well as synthetic applications of the newly developed catalysts, are discussed
Enhancement mode double top gated MOS nanostructures with tunable lateral geometry
We present measurements of silicon (Si) metal-oxide-semiconductor (MOS)
nanostructures that are fabricated using a process that facilitates essentially
arbitrary gate geometries. Stable Coulomb blockade behavior free from the
effects of parasitic dot formation is exhibited in several MOS quantum dots
with an open lateral quantum dot geometry. Decreases in mobility and increases
in charge defect densities (i.e. interface traps and fixed oxide charge) are
measured for critical process steps, and we correlate low disorder behavior
with a quantitative defect density. This work provides quantitative guidance
that has not been previously established about defect densities for which Si
quantum dots do not exhibit parasitic dot formation. These devices make use of
a double-layer gate stack in which many regions, including the critical gate
oxide, were fabricated in a fully-qualified CMOS facility.Comment: 11 pages, 6 figures, 3 tables, accepted for publication in Phys. Rev.
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