Optimal Energy Shaping Control for a Backdrivable Hip Exoskeleton

Task-dependent controllers widely used in exoskeletons track predefined trajectories, which overly constrain the volitional motion of individuals with remnant voluntary mobility. Energy shaping, on the other hand, provides task-invariant assistance by altering the human body's dynamic characteristics in the closed loop. While human-exoskeleton systems are often modeled using Euler-Lagrange equations, in our previous work we modeled the system as a port-controlled-Hamiltonian system, and a task-invariant controller was designed for a knee-ankle exoskeleton using interconnection-damping assignment passivity-based control. In this paper, we extend this framework to design a controller for a backdrivable hip exoskeleton to assist multiple tasks. A set of basis functions that contains information of kinematics is selected and corresponding coefficients are optimized, which allows the controller to provide torque that fits normative human torque for different activities of daily life. Human-subject experiments with two able-bodied subjects demonstrated the controller's capability to reduce muscle effort across different tasks

Exact field ionization rates in the barrier suppression-regime from numerical TDSE calculations

Numerically determined ionization rates for the field ionization of atomic hydrogen in strong and short laser pulses are presented. The laser pulse intensity reaches the so-called "barrier suppression ionization" regime where field ionization occurs within a few half laser cycles. Comparison of our numerical results with analytical theories frequently used shows poor agreement. An empirical formula for the "barrier suppression ionization"-rate is presented. This rate reproduces very well the course of the numerically determined ground state populations for laser pulses with different length, shape, amplitude, and frequency. Number(s): 32.80.RmComment: Enlarged and newly revised version, 22 pages (REVTeX) + 8 figures in ps-format, submitted for publication to Physical Review A, WWW: http://www.physik.tu-darmstadt.de/tqe

Knowledge-based critiquing of graphical user interfaces with CHIMES

CHIMES is a critiquing tool that automates the process of checking graphical user interface (GUI) designs for compliance with human factors design guidelines and toolkit style guides. The current prototype identifies instances of non-compliance and presents problem statements, advice, and tips to the GUI designer. Changes requested by the designer are made automatically, and the revised GUI is re-evaluated. A case study conducted at NASA-Goddard showed that CHIMES has the potential for dramatically reducing the time formerly spent in hands-on consistency checking. Capabilities recently added to CHIMES include exception handling and rule building. CHIMES is intended for use prior to usability testing as a means, for example, of catching and correcting syntactic inconsistencies in a larger user interface

Selective Inhibition of Human Monoamine Oxidase B by Acacetin 7-Methyl Ether Isolated from Turnera diffusa (Damiana)

© 2019 John Wiley & Sons Ltd Background: Bodybuilding supplements can cause a profound cholestatic syndrome. Aim: To describe the drug-Induced liver injury network\u27s experience with liver injury due to bodybuilding supplements. Methods: Liver injury pattern, severity and outcomes, potential genetic associations, and exposure to anabolic steroids by product analysis were analysed in prospectively enrolled subjects with bodybuilding supplement-induced liver injury with causality scores of probable or higher. Results: Forty-four males (mean age 33 years) developed liver injury with a median latency of 73 days. Forty-one per cent presented with hepatocellular pattern of liver injury as defined by the R \u3e 5 ([Fold elevation of ALT] ÷ [Fold elevation of Alk Phos] (mean, range = 6.4, 0.5-31.4, n = 42) despite all presenting with clinical features of cholestatic liver injury (100% with jaundice and 84% with pruritus). Liver biopsy (59% of subjects) demonstrated a mild hepatitis and profound cholestasis in most without bile duct injury, loss or fibrosis. Seventy-one per cent were hospitalised, and none died or required liver transplantation. In some, chemical analysis revealed anabolic steroid controlled substances not listed on the label. No enrichment of genetic variants associated with cholestatic syndromes was found, although mutations in ABCB11 (present in up to 20%) were significantly different than in ethnically matched controls. Conclusions: Patients with bodybuilding supplements liver injury uniformly presented with cholestatic injury, which slowly resolved. The ingested products often contained anabolic steroids not identified on the label, and no enrichment in genetic variants was found, indicating a need for additional studies

Alcohol Related Violence and Unwanted Sexual Activity on the College Campus

The purpose of this study was to explore the relationships among alcohol consumption, sexual assault and rape, and nonsexual violence in a college population at a large Northeastern university. A 49-item questionnaire was designed to elicit responses from both victims and perpetrators. Of the 1,084 respondents: 518 were male, 566 were female, the majority were White (91.8%), and in the 18-21 age range. Unwanted sexual activity, rape, and violence were significantly related to alcohol consumption on the college campus studied. These data indicated that alcohol was involved in: a) unwanted sexual activity--both from the victim\u27s perspective (85.7%) and from the perpetrator\u27s perspective (76.0%); b) rape--both from the victim\u27s perspective (69.0%) and from the perpetrator\u27s perspective (100%); and nonsexual violent acts from the same sex (59.5%), and (c) from the opposite sex (58.9%). The findings are consistent with those of previous studies that indicate a persistent trend in the negative consequences of violence linked to alcohol use and abuse among college students

VIKOR method for multiple criteria group decision making under 2-tuple linguistic neutrosophic environment

In this article, the VIKOR method is proposed to solve the multiple criteria group decision making (MCGDM) with 2-tuple linguistic neutrosophic numbers (2TLNNs). Firstly, the fundamental concepts, operation formulas and distance calculating method of 2TLNNs are introduced. Then some aggregation operators of 2TLNNs are reviewed. Thereafter, the original VIKOR method is extended to 2TLNNs and the calculating steps of VIKOR method with 2TLNNs are proposed. In the proposed method, it’s more reasonable and scientific for considering the conflicting criteria. Furthermore, the VIKOR are extended to interval-valued 2-tuple linguistic neutrosophic numbers (IV2TLNNs). Moreover, a numerical example for green supplier selection has been given to illustrate the new method and some comparisons are also conducted to further illustrate advantages of the new method

Is it safe? Talking to teens with HIV/AIDS about death and dying: a 3-month evaluation of Family Centered Advance Care (FACE) planning ? anxiety, depression, quality of life

Purpose To determine the safety of engaging HIV-positive (HIV+) adolescents in a Family Centered Advance Care (FACE) planning intervention. Patients and methods We conducted a 2-armed, randomized controlled clinical trial in 2 hospital-based outpatient clinics from 2006?2008 with HIV+ adolescents and their surrogates (n = 76). Three 60?90 minutes sessions were conducted weekly. FACE intervention groups received: Lyon FCACP Survey©, the Respecting Choices¬ interview, and completion of The Five Wishes©. The Healthy Living Control (HLC) received: Developmental History, Healthy Tips, Future Planning (vocational, school or vocational rehabilitation). Three-month post-intervention outcomes were: completion of advance directive (Five Wishes©); psychological adjustment (Beck Depression, Anxiety Inventories); quality of life (PedsQL?); and HIV symptoms (General Health Self-Assessment). Results Adolescents had a mean age, 16 years; 40% male; 92% African-American; 68% with perinatally acquired HIV, 29% had AIDS diagnosis. FACE participants completed advance directives more than controls, using time matched comparison (P \u3c 0.001). Neither anxiety, nor depression, increased at clinically or statistically significant levels post-intervention. FACE adolescents maintained quality of life. FACE families perceived their adolescents as worsening in their school (P = 0.018) and emotional (P = 0.029) quality of life at 3 months, compared with controls. Conclusions Participating in advance care planning did not unduly distress HIV+ adolescents

Airborne Lidar Measurements of Atmospheric Pressure Made Using the Oxygen A-Band

Accurate measurements of greenhouse gas mixing ratios on a global scale are currently needed to gain a better understanding of climate change and its possible impact on our planet. In order to remotely measure greenhouse gas concentrations in the atmosphere with regard to dry air, the air number density in the atmosphere is also needed in deriving the greenhouse gas concentrations. Since oxygen is stable and uniformly mixed in the atmosphere at 20.95%, the measurement of an oxygen absorption in the atmosphere can be used to infer the dry air density and used to calculate the dry air mixing ratio of a greenhouse gas, such as carbon dioxide or methane. OUT technique of measuring Oxygen uses integrated path differential absorption (IPDA) with an Erbium Doped Fiber Amplifier (EDF A) laser system and single photon counting module (SPCM). It measures the absorbance of several on- and off-line wavelengths tuned to an O2 absorption line in the A-band at 764.7 nm. The choice of wavelengths allows us to maximize the pressure sensitivity using the trough between two absorptions in the Oxygen A-band. Our retrieval algorithm uses ancillary meteorological and aircraft altitude information to fit the experimentally obtained lidar O2 line shapes to a model atmosphere and derives the pressure from the profiles of the two lines. We have demonstrated O2 measurements from the ground and from an airborne platform. In this paper we will report on our airborne measurements during our 2011 campaign for the ASCENDS program

Nanofluidic devices for rapid analysis of DNA and proteins

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references.Direct analysis of biologically-relevant entities such as nucleic acids and proteins offers the potential to outperform conventional analysis techniques and diagnostic methods through enhancements in speed, accuracy, and sensitivity. Nanofluidic systems with critical dimensions comparable to the molecular scale open up new possibilities for direct observation, manipulation and analysis of biomolecules (single or ensemble), thus providing a novel basis for ultra-sensitive and high-resolution sensors and medical diagnostic systems. Inspired by this concept, we have developed a new class of nanofluidic filter devices and have implemented them as controllable molecular sieves for rapid analytical separation of various physiologically-relevant molecules such as dsDNA and proteins. In addition, we have conducted theoretical studies of molecular sieving process in the context of periodic free-energy landscapes created by the patterned nanofluidic filter arrays. The kinetic model constructed based upon the equilibrium partitioning theory and the Kramers rate theory properly describes the field-dependent sieving behavior, presenting notable progress beyond the existing equilibrium model in conventional gels.(cont.) In this thesis, we have further developed a microfabricated anisotropic sieving structure consisting of a two-dimensional periodic nanofluidic filter array (anisotropic nanofilter array, ANA). The designed structural anisotropy in the ANA causes different-sized biomolecules to follow distinct migration trajectories, leading to efficient continuous-flow separation. Continuous-flow separation of dsDNA and proteins covering broad biological size scales were achieved within a few minutes, thus demonstrating the potential of the ANA as a generic molecular sieving structure for an integrated biomolecule sample preparation and analysis system.by Jianping Fu.Ph.D