Method and apparatus for positioning a robotic end effector

A robotic end effector and operation protocol for a reliable grasp of a target object irrespective of the target's contours is disclosed. A robotic hand includes a plurality of jointed fingers, one of which, like a thumb, is in opposed relation to the other. Each finger is comprised of at least two jointed sections, and provided with reflective proximity sensors, one on the inner surface of each finger section. Each proximity sensor comprises a transmitter of a beam of radiant energy and means for receiving reflections of the transmitted energy when reflected by a target object and for generating electrical signals responsive thereto. On the fingers opposed to the thumb, the proximity sensors on the outermost finger sections are aligned in an outer sensor array and the sensors on the intermediate finger sections and sensors on the innermost finger sections are similarly arranged to form an intermediate sensor array and an inner sensor array, respectively. The invention includes a computer system with software and/or circuitry for a protocol comprising the steps in sequence of: (1) approach axis alignment to maximize the number of outer layer sensors which detect the target; (2) non-contact contour following the target by the robot fingers to minimize target escape potential; and (3) closing to rigidize the target including dynamically re-adjusting the end effector finger alignment to compensate for target motion. A signal conditioning circuit and gain adjustment means are included to maintain the dynamic range of low power reflection signals

Smart hands for the EVA retriever

Dexterous, robotic hands are required for the extravehicular activity retriever (EVAR) system being developed by the NASA Johnson Space Center (JSC). These hands, as part of the EVAR system, must be able to grasp objects autonomously and securely which inadvertently separate from the Space Station. Development of the required hands was initiated in 1987. Outlined here are the hand development activities, including design considerations, progress to date, and future plans. Several types of dexterous hands that were evaluated, along with a proximity-sensing capability that was developed to initiate a reflexive, adaptive grasp, are described. The evaluations resulted in the design and fabrication of a 6-degree-of-freedom (DOF) hand that has two fingers and a thumb arranged in an anthropomorphic configuration. Finger joint force and position sensors are included in the design, as well as infrared proximity sensors which allow initiation of the grasp sequence when an object is detected within the grasp envelope

Effects of alirocumab on types of myocardial infarction: insights from the ODYSSEY OUTCOMES trial

Aims  The third Universal Definition of Myocardial Infarction (MI) Task Force classified MIs into five types: Type 1, spontaneous; Type 2, related to oxygen supply/demand imbalance; Type 3, fatal without ascertainment of cardiac biomarkers; Type 4, related to percutaneous coronary intervention; and Type 5, related to coronary artery bypass surgery. Low-density lipoprotein cholesterol (LDL-C) reduction with statins and proprotein convertase subtilisin–kexin Type 9 (PCSK9) inhibitors reduces risk of MI, but less is known about effects on types of MI. ODYSSEY OUTCOMES compared the PCSK9 inhibitor alirocumab with placebo in 18 924 patients with recent acute coronary syndrome (ACS) and elevated LDL-C (≥1.8 mmol/L) despite intensive statin therapy. In a pre-specified analysis, we assessed the effects of alirocumab on types of MI. Methods and results  Median follow-up was 2.8 years. Myocardial infarction types were prospectively adjudicated and classified. Of 1860 total MIs, 1223 (65.8%) were adjudicated as Type 1, 386 (20.8%) as Type 2, and 244 (13.1%) as Type 4. Few events were Type 3 (n = 2) or Type 5 (n = 5). Alirocumab reduced first MIs [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77–0.95; P = 0.003], with reductions in both Type 1 (HR 0.87, 95% CI 0.77–0.99; P = 0.032) and Type 2 (0.77, 0.61–0.97; P = 0.025), but not Type 4 MI. Conclusion  After ACS, alirocumab added to intensive statin therapy favourably impacted on Type 1 and 2 MIs. The data indicate for the first time that a lipid-lowering therapy can attenuate the risk of Type 2 MI. Low-density lipoprotein cholesterol reduction below levels achievable with statins is an effective preventive strategy for both MI types.For complete list of authors see http://dx.doi.org/10.1093/eurheartj/ehz299</p

Effect of alirocumab on mortality after acute coronary syndromes. An analysis of the ODYSSEY OUTCOMES randomized clinical trial

Background: Previous trials of PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitors demonstrated reductions in major adverse cardiovascular events, but not death. We assessed the effects of alirocumab on death after index acute coronary syndrome. Methods: ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was a double-blind, randomized comparison of alirocumab or placebo in 18 924 patients who had an ACS 1 to 12 months previously and elevated atherogenic lipoproteins despite intensive statin therapy. Alirocumab dose was blindly titrated to target achieved low-density lipoprotein cholesterol (LDL-C) between 25 and 50 mg/dL. We examined the effects of treatment on all-cause death and its components, cardiovascular and noncardiovascular death, with log-rank testing. Joint semiparametric models tested associations between nonfatal cardiovascular events and cardiovascular or noncardiovascular death. Results: Median follow-up was 2.8 years. Death occurred in 334 (3.5%) and 392 (4.1%) patients, respectively, in the alirocumab and placebo groups (hazard ratio [HR], 0.85; 95% CI, 0.73 to 0.98; P=0.03, nominal P value). This resulted from nonsignificantly fewer cardiovascular (240 [2.5%] vs 271 [2.9%]; HR, 0.88; 95% CI, 0.74 to 1.05; P=0.15) and noncardiovascular (94 [1.0%] vs 121 [1.3%]; HR, 0.77; 95% CI, 0.59 to 1.01; P=0.06) deaths with alirocumab. In a prespecified analysis of 8242 patients eligible for ≥3 years follow-up, alirocumab reduced death (HR, 0.78; 95% CI, 0.65 to 0.94; P=0.01). Patients with nonfatal cardiovascular events were at increased risk for cardiovascular and noncardiovascular deaths (P<0.0001 for the associations). Alirocumab reduced total nonfatal cardiovascular events (P<0.001) and thereby may have attenuated the number of cardiovascular and noncardiovascular deaths. A post hoc analysis found that, compared to patients with lower LDL-C, patients with baseline LDL-C ≥100 mg/dL (2.59 mmol/L) had a greater absolute risk of death and a larger mortality benefit from alirocumab (HR, 0.71; 95% CI, 0.56 to 0.90; Pinteraction=0.007). In the alirocumab group, all-cause death declined wit h achieved LDL-C at 4 months of treatment, to a level of approximately 30 mg/dL (adjusted P=0.017 for linear trend). Conclusions: Alirocumab added to intensive statin therapy has the potential to reduce death after acute coronary syndrome, particularly if treatment is maintained for ≥3 years, if baseline LDL-C is ≥100 mg/dL, or if achieved LDL-C is low. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01663402

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Area-selective ALD of titanium dioxide using lithographically defined poly (methyl methacrylate) films

© 2006 The Electrochemical Society, Inc. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS).An approach to area-selective atomic layer deposition techniques based on the use of a lithographically definable polymeric masking layer has been reported. Successful direct patterned deposition of TiO2 is demonstrated using a poly methyl methacrylate masking layer that has been patterned using deep-UV lithography. A number of factors which must be considered in designing patternable polymeric masking materials and processes have been determined and are briefly discussed, including reactivity of the polymer with the atomic layer deposited ALD precursor species, diffusion of ALD precursors through the polymer mask, and remnant precursor content in the masking film during ALD cycling

A top surface imaging method using area selective ALD on chemically amplified polymer photoresist films

© 2006 The Electrochemical Society, Inc. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS).A method for performing top surface imaging TSI on a single polymeric photoresist film using area selective atomic layer deposition ALD is presented. In this method, exposure of the polymer thin film creates reactive hydroxyl sites on the film surface in the exposed areas that subsequently act as nucleation and growth sites for deposition of metal oxide features using a chemically selective atomic layer deposition process. Specifically, it is shown that titanium isopropoxide and water can be used as ALD precursors in conjunction with a chemically amplified photoresist film, formulated using a protected polymer poly tert-butyl methacrylate and a photoacid generator triphenylsulfonium tris perfluoromethanesulfonyl methide , to successfully perform such an area selective ALD TSI process. Using this material set and methodology, micrometer-scale photoresist features are defined, metal oxide patterns are produced, and these patterns have been transferred through the polymer film via plasma etching. One unique feature of this TSI process is that it has been achieved without requiring a descum etch, which is commonly needed with other TSI methods, due to the highly selective nature of the ALD process

Patterning via surface monolayer initiated polymerization: A study of surface initiator photoreaction kinetics

© 2004 American Vacuum Society. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Vacuum Society. The electronic version of this article is the complete one and can be found at: http://dx.doi.org/10.1116/1.1824061DOI: 10.1116/1.1824061Surface monolayer initiated polymerization (SMIP) is a potential method for achieving high resolution patterning of surfaces and materials that could be used as an alternative to conventional lithographic methods based on photoresist thin films. This article reports on the photochemical kinetic rate constants of two candidate azo-type surface bound photoradical initiator molecules. X-ray photoelectron spectroscopy was utilized to monitor the relative concentration of azo initiator on a silicon surface as a function of exposure dose to 248 nm radiation. This photochemical decomposition data showed that the photoreaction for both initiators followed first order kinetics with photoreaction rate constants in the range of 4.5×10⁻³ cm²∕mJ to 9.7×10⁻³ cm²∕mJ. The difference in the observed rate constants for the two azo initiators was attributed primarily to differences in their quantum efficiencies. These differences in quantum efficiency were attributed to the size of the nontethered fragment that would be produced from the initiator, with larger fragments producing slower photochemical decomposition kinetics. Thus, photoradical initiators with small non-surface bound fragments are desirable in terms of increasing the photosensitivity of such SMIP processes. For successful positive tone imaging using a SMIP process with photoradical initiators, it was estimated that approximately 99% of the monolayer must be decomposed in order to produce images in the resulting polymer layers. Using this information in conjunction with the photochemical reaction rate constants for the azo initiators, exposure doses on the order of 400 mJ∕cm² and larger would be required for the present initiators

Transport behavior of atomic layer deposition precursors through polymer masking layers: Influence on area selective atomic layer deposition

© 2007 American Vacuum Society. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Vacuum Society. The electronic version of this article is the complete one and can be found at: http://dx.doi.org/10.1116/1.2782546DOI: 10.1116/1.2782546Sorption and diffusion of precursors through polymer layers were considered as limitations to the successful implementation of a polymer film-based masking approach to area selective atomic layer deposition techniques (ASALDT). Quartz crystal microbalance studies were used to estimate solubility and diffusivity of ALD precursors through supported thin polymer films at elevated temperatures. Specifically, measurements have been performed to estimate the solubility of water in polyhydroxystyrene, polymethylmethacrylate (PMMA), and hexafluoroisopropylalcohol polynorbornene. In addition, diffusion coefficients and solubilities of titanium tetrachloride (TiCl₄) and titanium isopropoxide (Ti(ipr)₄ through PMMAhave also been determined. The results suggest that polymer films exhibit insignificant water uptake at high temperature (~160 °C) and, hence, sorption of water into polymer films does not pose limitations to polymer masking-based ASALDT. Diffusion coefficient measurements of metal precursors account for the role of precursor size in determining the minimum polymer masking layer thickness for a successful ASALDT process