Using X-ray Fluorescence to Analyze Fire Impacted Soil and Vegetation Composition

In our lab, I am using an X-ray fluorescence (XRF) to measure the concentrations of metals in sediments from subalpine lakes. Our goal is to measure the biogeochemical consequences of wildfires over the last 2000 years. This study looks at the elemental composition of different lake cores, and vegetation samples from areas of the “Big Burn” fire of 1910. This fire burned across several states in the Rocky Mountain region. With our XRF data we are able to see how the fire impacted the soils and how long after the fire proper soil composition can occur. This study can be used to help understand the impacts of large scale fires on local ecosystems

Can real-time visual feedback during gait retraining reduce metabolic demand for individuals with transtibial amputation?

The metabolic demand of walking generally increases following lower extremity amputation. This study used real-time visual feedback to modify biomechanical factors linked to an elevated metabolic demand of walking in individuals with transtibial amputation. Eight persons with unilateral, traumatic transtibial amputation and 8 uninjured controls participated. Two separate bouts of real-time visual feedback were provided during a single session of gait retraining to reduce 1) center of mass sway and 2) thigh muscle activation magnitudes and duration. Baseline and post-intervention data were collected. Metabolic rate, heart rate, frontal plane center of mass sway, quadriceps and hamstrings muscle activity, and co-contraction indices were evaluated during steady state walking at a standardized speed. Visual feedback successfully decreased center of mass sway 12% (p = 0.006) and quadriceps activity 12% (p = 0.041); however, thigh muscle co-contraction indices were unchanged. Neither condition significantly affected metabolic rate during walking and heart rate increased with center-of-mass feedback. Metabolic rate, center of mass sway, and integrated quadriceps muscle activity were all not significantly different from controls. Attempts to modify gait to decrease metabolic demand may actually adversely increase the physiological effort of walking in individuals with lower extremity amputation who are young, active and approximate metabolic rates of able-bodied adults

John Adams

John Adams nació en Massachusetts, en una familia con inclinaciones musicales. Se inició con el clarinete, pero mostró un talento temprano para la composición

Comparison of walking overground and in a Computer Assisted Rehabilitation Environment (CAREN) in individuals with and without transtibial amputation

Background Due to increased interest in treadmill gait training, recent research has focused on the similarities and differences between treadmill and overground walking. Most of these studies have tested healthy, young subjects rather than impaired populations that might benefit from such training. These studies also do not include optic flow, which may change how the individuals integrate sensory information when walking on a treadmill. This study compared overground walking to treadmill walking in a computer assisted virtual reality environment (CAREN) in individuals with and without transtibial amputations (TTA). Methods Seven individuals with traumatic TTA and 27 unimpaired controls participated. Subjects walked overground and on a treadmill in a CAREN at a normalized speed. The CAREN applied optic flow at the same speed that the subject walked. Temporal-spatial parameters, full body kinematics, and kinematic variability were collected during all trials. Results Both subject groups decreased step time and control subjects decreased step length when walking in the CAREN. Differences in lower extremity kinematics were small (\u3c 2.5○) and did not exceed the minimal detectable change values for these measures. Control subjects exhibited decreased transverse and frontal plane range of motion of the pelvis and trunk when walking in the CAREN, while patients with TTA did not. Both groups exhibited increased step width variability during treadmill walking in the CAREN, but only minor changes in kinematic variability. Conclusions The results of this study suggest that treadmill training in a virtual environment should be similar enough to overground that changes should carry over. Caution should be made when comparing step width variability and step time results from studies utilizing a treadmill to those overground

Structural Overlay Strategies for Jointed Concrete Pavements. Volume IV: Guidelines for the Selection of Rehabilitation Alternatives

DTFH61-86-C-00079A major field study and evaluation has been conducted into the effectiveness of three structural overlay types for portland cement concrete (PCC) pavements. These include sawing and sealing asphalt concrete (AC) overlays of PCC pavements, cracking and seating PCC pavements prior to AC overlay, and constructing a thin bonded PCC overlay on top of the existing PCC pavement. Condition surveys, deflection testing, and roughness measurements were performed on a total of 55 sections. The performance of these sections was evaluated and the effectiveness of each overlay type analyzed. Based on the field data, guidelines were developed for the use of these structural overlays. This volume provides detailed guidelines and case studies prepared specifically for the practicing engineer as an aid in the evaluation and rehabilitation of jointed concrete pavements. Feasibility guidelines are given for restoration, resurfacing, and reconstruction alternatives in terms of constructability, future life and life-cycle costs. New prediction models are developed for bonded PCC overlays, sawing and sealing and AC overlay, and cracking and seating and AC overlay. The EXPEAR program was extensively modified to include the above rehabilitation alternatives and improved predictive models and to provide for much easier usage by the practicing engineer for evaluation and rehabilitation. Detailed rehabilitation case studies are presented that will be of interest to the practicing engineer

Structural Overlay Strategies for Jointed Concrete Pavements. Volume VI: Appendix A, User's Manual for the EXPEAR Computer Program

DTFH61-86-C-00079A major field study and evaluation has been conducted into the effectiveness of three structural overlay types for portland cement concrete (PCC) pavements. These include sawing and sealing asphalt concrete (AC) overlays of PCC pavements, cracking and seating PCC pavements prior to AC overlay, and constructing a thin bonded PCC overlay on top of the existing PCC pavement. Condition surveys, deflection testing, and roughness measurements were performed on a total of 55 sections. The performance of these sections was evaluated and the effectiveness of each overlay type analyzed. Based on the field data, guidelines were developed for the use of structural overlays. This volume provides a users guide to the EXPEAR computerized system to assist practicing engineers in evaluating concrete highway pavements, in developing feasible rehabilitation alternatives, and in predicting the performance and cost-effectiveness of the alternatives. EXPEAR is intended for use by State highway engineers in project-level rehabilitation planning and design for conventional concrete pavements (JRCP, JPCP, and CRCP). EXPEAR uses information about the pavement to guide the engineer through evaluation of a pavement's present condition and development of one or more feasible rehabilitation strategies. A computer program has been developed for each of the three pavement types addressed. The EXPEAR version 1.4 program operates on any IBM-compatible personal computer. Extensive revisions were made in EXPEAR 1.4 to improve the user-friendliness of the program and its capabilities

Tolerability of subcutaneous immunoglobulin 20%, Ig20Gly, in pediatric patients with primary immunodeficiencies

Aim: To assess Ig20Gly tolerability in pediatric patients with primary immunodeficiencies. Patients & methods: Infusion parameters and tolerability were analyzed in pediatric patients (aged 2-5 years [n=6], 6-11 years [n=22] and 12-17 years [n=22]) receiving Ig20Gly in two Phase II/III trials. Results: Of 2624 Ig20Gly infusions, >99% did not require any rate reduction, interruption or discontinuation due to adverse events (AEs). Median maximum infusion rates and volumes/site were higher in patients 12-17 years of age (30ml/h/site; 30ml/site) versus 6-11 years (20ml/h/site; 15ml/site) and 2-5 years (18ml/h/site; 14ml/site). Rates of causally related systemic and local AEs (0.009 and 0.063 AEs/infusion) were low. Conclusion: Ig20Gly infused at relatively high rates and volumes was well tolerated in children

Biomechanics of ramp descent in unilateral trans-tibial amputees: Comparison of a microprocessor controlled foot with conventional ankle–foot mechanisms

yesBackground Walking down slopes and/or over uneven terrain is problematic for unilateral trans-tibial amputees. Accordingly, ‘ankle’ devices have been added to some dynamic-response feet. This study determined whether use of a microprocessor controlled passive-articulating hydraulic ankle–foot device improved the gait biomechanics of ramp descent in comparison to conventional ankle–foot mechanisms. Methods Nine active unilateral trans-tibial amputees repeatedly walked down a 5° ramp, using a hydraulic ankle–foot with microprocessor active or inactive or using a comparable foot with rubber ball-joint (elastic) ‘ankle’ device. When inactive the hydraulic unit's resistances were those deemed to be optimum for level-ground walking, and when active, the plantar- and dorsi-flexion resistances switched to a ramp-descent mode. Residual limb kinematics, joints moments/powers and prosthetic foot power absorption/return were compared across ankle types using ANOVA. Findings Foot-flat was attained fastest with the elastic foot and second fastest with the active hydraulic foot (P < 0.001). Prosthetic shank single-support mean rotation velocity (p = 0.006), and the flexion (P < 0.001) and negative work done at the residual knee (P = 0.08) were reduced, and negative work done by the ankle–foot increased (P < 0.001) when using the active hydraulic compared to the other two ankle types. Interpretation The greater negative ‘ankle’ work done when using the active hydraulic compared to other two ankle types, explains why there was a corresponding reduction in flexion and negative work at the residual knee. These findings suggest that use of a microprocessor controlled hydraulic foot will reduce the biomechanical compensations used to walk down slopes