Non-Invasive Examination of the Role of Local Muscle O2 Delivery in Determining VO2 Kinetics During Moderate-Intensity ‘Step’ and Ramp Incremental Exercise

This thesis was undertaken to examine the physiological mechanisms that interact to govern the adjustment of O2 uptake (VO2) during the on-transient of moderate-intensity exercise as well as during incremental exercise, using non-invasive measures. Particular emphasis was placed on the information provided by pairing breath-by-breath pulmonary VO2 measures with near-infrared spectroscopy (NIRS)-derived measures to investigate the role of local muscle O2 delivery in the determination of VO2 during various exercise challenges. The main findings were that: 1) local muscle O2 delivery likely plays a rate-limiting role in the determination of τVO2p (at least when τVO2p is greater than ~20 s), even in young, healthy adults; 2) τVO2p can be reduced by augmenting local muscle O2 delivery (with heavy-intensity ‘priming’ exercise) and increased by impairing local muscle O2 delivery (with acute, mild hypoxia); 3) the relative slowing of the VO2 on-kinetics response when moderate-intensity exercise is initiated from an elevated baseline WR does not appear to be the result of reduced local muscle O2 delivery in older adults; 4) whereas the effects of moderate-intensity work rate (WR) increment were heterogeneous with respect to τVO2p in those with fast versus slow VO2 kinetics, increasing WR increments were associated with increasing O2 costs (i.e., functional gain; G = ΔVO2/ΔWR) regardless of the rate of adjustment; this suggests that τVO2p and functional G may be dissociated; and 5) the appropriateness of a sigmoid regression to characterize the overall Δ[HHb] response to incremental exercise (at least for comparative purposes) was challenged, and a ‘double-linear’ model was proposed as an alternative

The effects of physical activity and maturation on boys' (8 to 16 years) running economy

Previous reports have demonstrated that running economy (RE), a measure of efficiency of locomotion, is superior in adults than in children; however, it is unclear how these differences come to be. Purpose: To identify the effect of maturity status, physical activity and various other anatomical and physiological factors on RE development in boys aged 8 to 16 years. Methods: Data were collected as part of the Saskatchewan Growth and Development Study (SGDS; 1964-1973). Using a pure longitudinal study design, anthropometric, maturity, physiological characteristics (treadmill run) and physical activity were assessed annually for nine consecutive years. Two-hundred and two eight year-old males were measured in 1965; by 1973, complete longitudinal data were available for 63 participants. During the treadmill run, a measure of submaximal oxygen consumption (VO2) was recorded, an index of RE. Four approaches of normalizing VO2 to body size were investigated. Maturity status was determined based upon chronological age at peak height velocity (PHV). Physical activity was assessed by two teacher ratings and two questionnaires. Results: Normalizing VO2 to body surface area was found to be the most appropriate body size adjustment. Submaximal VO2 (ml/m^2/min) at 9.6 km/h decreased with increasing chronological age (

The Spatial Variability of Crime: A Review of Methodological Choice, Proposed Models, and Methods for Illustrating the Phenomenon

The spatial analysis of crime has occurred for nearly two centuries. Within criminology, research interests that have developed from the use of spatial methodologies seek to identify the spatial variability and concentration of crime. The first focus utilizes spatial statistics and mapping to describe and illustrate spatial variability. The second focus uses statistical techniques to describe levels of concentration such as the percentage of crime attributed to a unit. Due to the larger breadth of work and multiple analytical components the former will be the focus of this research. This multi-study dissertation explores the methods currently used to study the spatial variability of crime, presents a novel method to do so within and between U.S. cities, and demonstrates innovative ways to illustrate it. The first study is a systematic review of the literature on the spatial variability of crime during the last decade (2010- 2019). Using protocols based on a systematic literature review this study reviews the relevant literature and reports on the methods and findings of selected research. Trends were identified that show a lack of cohesiveness across the studies regarding choice of methodology and unit selection. However, an emphasis on using micro-units was observed across the studies. The second study explores the spatial variability of crime within and between U.S. cities. Variance partitioning of multi-level models were estimated to observe the crime variance attributed to each unit of analysis. The majority of the spatial variability of crime can be attributed to micro-units. However, larger spatial units provide greater context within cities and particularly between cities as spatial variability was observed to vary among the examined cities. The third study highlights the importance of crime mapping and explores methods to map the spatial variability of crime. Innovative techniques such as dynamic maps are used to illustrate the adaptability of crime mapping and suggestions are made for their continued use. Overall, this dissertation contributes to the crime and place literature by examining past methodologies, presenting new ones, and incorporating mapping into research on the spatial variability of crime

Impaired Hyperemic Response to Exercise Post Stroke

Individuals with chronic stroke have reduced perfusion of the paretic lower limb at rest; however, the hyperemic response to graded muscle contractions in this patient population has not been examined. This study quantified blood flow to the paretic and non-paretic lower limbs of subjects with chronic stroke after submaximal contractions of the knee extensor muscles and correlated those measures with limb function and activity. Ten subjects with chronic stroke and ten controls had blood flow through the superficial femoral artery quantified with ultrasonography before and immediately after 10 second contractions of the knee extensor muscles at 20, 40, 60, and 80% of the maximal voluntary contraction (MVC) of the test limb. Blood flow to the paretic and non-paretic limb of stroke subjects was significantly reduced at all load levels compared to control subjects even after normalization to lean muscle mass. Of variables measured, increased blood flow after an 80% MVC was the single best predictor of paretic limb strength, the symmetry of strength between the paretic and non-paretic limbs, coordination of the paretic limb, and physical activity. The impaired hemodynamic response to high intensity contractions was a better predictor of lower limb function than resting perfusion measures. Stroke-dependent weakness and atrophy of the paretic limb do not explain the reduced hyperemic response to muscle contraction alone as the response is similarly reduced in the non-paretic limb when compared to controls. These data may suggest a role for perfusion therapies to optimize rehabilitation post stroke

Magnetically-controlled velocity selection in a cold atom sample using stimulated Raman transitions

We observe velocity-selective two-photon resonances in a cold atom cloud in the presence of a magnetic field. We use these resonances to demonstrate a simple magnetometer with sub-mG resolution. The technique is particularly useful for zeroing the magnetic field and does not require any additional laser frequencies than are already used for standard magneto-optical traps. We verify the effects using Faraday rotation spectroscopy.Comment: 5 pages, 6 figure

Cold atom confinement in an all-optical dark ring trap

We demonstrate confinement of $^{85}$Rb atoms in a dark, toroidal optical trap. We use a spatial light modulator to convert a single blue-detuned Gaussian laser beam to a superposition of Laguerre-Gaussian modes that forms a ring-shaped intensity null bounded harmonically in all directions. We measure a 1/e spin-relaxation lifetime of ~1.5 seconds for a trap detuning of 4.0 nm. For smaller detunings, a time-dependent relaxation rate is observed. We use these relaxation rate measurements and imaging diagnostics to optimize trap alignment in a programmable manner with the modulator. The results are compared with numerical simulations.Comment: 5 pages, 4 figure

NCERA-101 Station Report from Kennedy Space Center, FL, USA (April 2019)

This is our annual "station report" of activities related to controlled environment research to the North Central Education Research Activity (NCERA-101) committee. The committee is sponsored the USDA National Institute for Food and Agriculture (NIFA). Kennedy Space Center has participated in this committee for over 30 years

Ischemic Conditioning Increases Strength and Volitional Activation of Paretic Muscle in Chronic Stroke: A Pilot Study

7siIschemic conditioning (IC) on the arm or leg has emerged as an intervention to improve strength and performance in healthy populations, but the effects on neurologic populations are unknown. The purpose of this study was to quantify the effects of a single session of IC on knee extensor strength and muscle activation in chronic stroke survivors. Maximal knee extensor torque measurements and surface EMG were quantified in 10 chronic stroke survivors (>1 year post-stroke) with hemiparesis before and after a single session of IC or Sham on the paretic leg. IC consisted of five minutes of compression with a proximal thigh cuff (inflation pressure = 225 mmHg for IC or 25 mmHg for Sham) followed by five minutes of rest. This was repeated five times. Maximal knee extensor strength, EMG magnitude, and motor unit firing behavior were measured before and immediately after IC or Sham. IC increased paretic leg strength by 10.6plus minus8.5 Nm while no difference was observed in the Sham group (change in Sham = 1.3plus minus2.9 Nm; p = 0.001 IC vs. Sham). IC-induced increases in strength were accompanied by a 31plus minus15% increase in the magnitude of muscle EMG during maximal contractions and a 5% decrease in motor unit recruitment thresholds during sub-maximal contractions. Individuals who had the most asymmetry in strength between their paretic and non-paretic legs had the largest increases in strength (r2= 0.54). This study provides evidence that a single session of IC can increase strength through improved muscle activation in chronic stroke survivors.openembargoed_20190204Hyngstrom, Allison S; Murphy, Spencer A; Nguyen, Jennifer; Schmit, Brian D; Negro, Francesco; Gutterman, David D; Durand, Matthew JHyngstrom, Allison S; Murphy, Spencer A; Nguyen, Jennifer; Schmit, Brian D; Negro, Francesco; Gutterman, David D; Durand, Matthew

Lessons from Laparoscopic Liver Surgery: A Nine-Year Case Series

Objective. This series describes a developing experience in laparoscopic liver surgery presenting results from 40 procedures including right hemihepatectomy, left lateral lobectomy, and microwave ablation therapy. Methods. Forty patients undergoing laparoscopic liver surgery between September 1997 and November 2006 were included. The data set includes: operative procedure and duration, intraoperative blood loss, conversion to open operation rates, length of hospital stay, complications, mortality, histology of lesions/resection margins, and disease recurrence. Results. Mean age of patient: 59 years, 17/40 male, 23/40 female, 23/40 of lesions were benign, and 17/40 malignant. Operations included: laparoscopic anatomical resections n = 15, nonanatomical resections n = 11, microwave ablations n = 8 and deroofing of cysts n = 7. Median anaesthetic time: 120 minutes (range 40–240), mean blood loss 78 mL and 1/40 conversions to open. Median resection margins were 10 mm (range 1–14) and median length of stay 3 days (range 1–10). Operative and 30-day mortality were zero with no local disease recurrence. Conclusion. Laparoscopic liver surgery appears safe and effective and is associated with reduced hospital stay. Larger studies are required to confirm it is oncologically sound

Costs of preparing to implement a virtual reality job interview training programme in a community mental health agency: A budget impact analysis

Rational, aims and objectivesIndividual Placement and Support (IPS) is an evidence based strategy for facilitating employment among adults with severe mental illness (SMI) where staff may lead mock job interviews to prepare clients for real- world interviews (a method with limited scalability and cost effectiveness). A virtual reality job interview training program (VR- JIT)- delivered via the internet- has demonstrated efficacy for increasing employment among adults with SMI. Now, VR- JIT is being implemented with a community mental health agency (CMHA) and evaluated for its effectiveness within IPS. This study is a budget impact analysis, evaluating the costs of preparing a CMHA to implement VR- JIT.MethodImplementation preparation occurred over 7 months from October 1, 2016 to April 30, 2017. CMHA staff (n- =- 15) and external research partners (n- =- 3) tracked their hours completing implementation preparation activities. Salaries plus a 28% fringe benefit rate were used to derive a per- hour salary amount for each individual and applied to each activity. Non- labor equipment costs were obtained from purchase receipts. A budget impact analysis evaluated the expenditures associated with preparing the CMHA to implement VRJIT.ResultsThe total implementation preparation costs equaled $25,482. Labor costs equaled$22,882 and non- labor costs equaled $2,600. In total, 655 person- hours were spent preparing for VR- JIT implementation (e.g., preparing lab space, training, and supervising operations).ConclusionsThis study presents an initial evaluation of the budget impact of preparing to implement VR- JIT in a CMHA. Cost considerations for future implementation preparation will be discussed. Given that the cost to prepare to implement an intervention can hinder its adoption, results provide an important analysis for decision- makers that may enhance uptake. Future work will determine the cost- effectiveness of VR- JIT implemented within IPS. This study is registered at http://clinicaltrials.gov, NCT- =- 03049813, - Virtual Reality Job Interview Training: An Enhancement to Supported Employment in Severe Mental Illness.-Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156238/2/jep13292.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156238/1/jep13292_am.pd