Characterizing the surface quality and droplet interface shape for microarray plates.

The variation in the surface quality of microarray plates was examined by measuring the contact angles of 480 droplets on five microarray plates. It was found that the measured contact angle did not accurately predict the droplet shape for moderate Bond numbers (~0.5 ≤ N(B) ≤ 5). By defining an apparent contact angle using the ratio of the contact radius to the height, the variance in the predicted interface shape decreased by greater than a factor of 3 for both local and globally averaged characteristics. The error in the predicted droplet height was also reduced by 3 orders of magnitude.

An empirically validated analytical model of droplet dynamics in electrowetting on dielectric devices.

Explicit analytical models that describe the capillary force on confined droplets actuated in electrowetting on dielectric devices and the reduction in that force by contact angle hysteresis as a function of the three-dimensional shape of the droplet interface are presented. These models are used to develop an analytical model for the transient position and velocity of the droplet. An order of magnitude analysis showed that droplet motion could be modeled using the driving capillary force opposed by contact angle hysteresis, wall shear, and contact line friction. Droplet dynamics were found to be a function of gap height, droplet radius, surface tension, fluid density, the initial and deformed contact angles, contact angle hysteresis, and friction coefficients pertaining to viscous wall friction and contact line friction. The first four parameters describe the device geometry and fluid properties; the remaining parameters were determined experimentally. Images of the droplet during motion were used to determine the evolution of the shape, position, and velocity of the droplet with time. Comparisons between the measured and predicted results show that the proposed model provides good accuracy over a range of practical voltages and droplet aspect ratios.

Relationship between motor FIM and muscle strength in lower cervical-level spinal cord injuries.

STUDY DESIGN: Retrospective analysis. OBJECTIVES: The objectives of this research were to, in subjects with lower cervical spinal cord injury (SCI), examine the relationship between strength of muscle groups as measured by the manual muscle test (MMT) and function (reflected as burden of care) as measured by individual functional independence measure (FIM) motor tasks, and investigate the extent to which MMT scores explain the variance of the motor FIM scores. SETTING: Acute rehabilitation hospitals, Boston, MA, USA. METHODS: Retrospective pilot study of 20 in-patients, age 18-62 years, with an SCI between C5 and C7. Discharge demographic variables, MMT and motor FIM scores were analyzed. Descriptive statistics, Spearman's rank correlation coefficients, stepwise regressions were performed. RESULTS: MMT scores for elbow flexion followed by shoulder flexion and wrist extension correlated with the greatest number of FIM tasks. MMT scores explained some part of the variance in the eight of 12 motor FIM tasks. In six of eight tasks, one key muscle explained a large portion of the variance. CONCLUSION: Key muscles relative to FIM tasks can be identified. These findings may help focus therapeutic interventions aimed at achievement in these tasks.

Balance and physical impairments after stroke.

OBJECTIVE: To investigate the relationship among laboratory and clinical balance measures and physical impairments. DESIGN: A descriptive correlational study. SETTING: Research laboratory. PARTICIPANTS: Thirty subjects with stroke, recruited through convenience sampling. MAIN OUTCOME MEASURES: Postural sway was calculated in terms of center of pressure (COP) parameters including spectral characteristics. Clinical balance was measured using the Balance Scale. The assessed physical impairments included stages of lower limb motor recovery, ankle proprioception, and passive dorsiflexion range of the involved limb. RESULTS: The Balance Scale was correlated with COP speed (r = -.57), COP root mean square speed (r = -.50), and COP mean frequency (r = -.50) in the anterior-posterior direction only. Moderate to high correlations were found among most of the COP parameters except spectral characteristics. Significant differences in postural sway were found among different stance in eyes-open (p = .00 to .02) and eyes-closed conditions (p = .00 to .04). Subjects with impaired ankle proprioception had significantly increased postural sway and decreased Balance Scale scores when compared with the subjects with intact ankle proprioception. CONCLUSIONS: Some of the clinical and laboratory balance assessments were related, indicating that some components of the tests are similar, but some measured different aspects of balance. Postural sway was related to visual condition, stance position, and proprioception.

Gain of muscle torque at low and high speed after isokinetic knee strengthening program in healthy young and older adults.

Low-speed isokinetic exercise has been recommended to exert a maximal contraction and produce greater muscle torque than high-speed exercise in young adults. The purpose of this study was to compare the effectiveness of low- and high-speed isokinetic exercise programs for increasing muscle torque in young and elderly people. Twenty healthy elderly and 20 young subjects participated. The elderly subjects were divided into two groups. One group performed high-speed (300 degrees/s) isokinetic exercise training three times a week for the dominant-side knee extensor and low-speed (60 degrees/s) exercise for the non-dominant side for 6 weeks. The other group was trained using the reverse exercise regime. The training program for the young subjects was the same as that for the elderly groups. All subjects had their knee extensor torque evaluated with an isokinetic test before and at 2-week intervals during the training program. For young and elderly groups, both high- and low-speed isokinetic exercise training increased extensor torque in low- and high-speed tests. For the young group, low-speed exercise effectively improved muscle torque at low and high speeds. The improvement in slow muscle torque was significantly greater than that in fast muscle torque. For the elderly subjects, high-speed isokinetic exercise produced the greatest muscle torque at high speed in the first 2 weeks of training, and demonstrated a sharp increase in muscle torque in the final 2 weeks. Low-speed exercise frequently caused knee stress and the inability of some elder subjects to continue the exercises with maximal effort. Our findings indicate that high-speed exercise may be more appropriate for the elderly, and low-speed exercise may be more appropriate for younger people.

Initial small-volume hypertonic resuscitation of shock and brain injury: short- and long-term effects.

BACKGROUND: Initial small-volume hypertonic saline resuscitation of a combined hemorrhagic shock and head injury model was studied. METHODS: Twenty-three sheep underwent hemorrhage (20 mL/kg) and parietal freeze injury followed by initial bolus resuscitation with lactated Ringer's solution (40 mL/kg) or 7.5% hypertonic saline (HS) (4 mL/kg). Cardiac index was maintained with lactated Ringer's solution for either 2 or 24 hours. Parietal lobe water content, blood volume, and blood flow were determined. Intracranial pressure (millimeters of mercury) was followed. RESULTS: Overall fluid requirements (milliliters per kilogram) were less at 2 and 24 hours with HS resuscitation. Early intracranial pressure was less with HS resuscitation. Brain water contents were similar between groups. Blood flow in injured and blood volume in uninjured parietal lobe were less for HS at 2 hours, although not different at 24 hours. CONCLUSIONS: Less fluid was needed in the short- and long-term with HS resuscitation. Early intracranial pressure was higher with lactated Ringer's solution resuscitation, possibly in part owing to increased blood volume.

The nutrient intake of women with bulimia nervosa.

OBJECTIVE: The objective of this study was to evaluate the meal patterns and nutrient intake of women with bulimia nervosa (BN), and to compare them to clinical variables and recommended dietary allowances (RDA). METHOD: The nutrient intake of 50 women with BN was analyzed from 14 day dietary records. The data were compared to the median intakes of a random sample of women and to the RDA. Clinical variables for the women with BN were also available. RESULTS: Compared to nonbinge episodes per day, binge eating was significantly higher in energy from sucrose, fat, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and lower in protein. Compared to the population median, binge eating was significantly lower in percent energy from protein, and higher in percent carbohydrate (CHO), sucrose, SFA, and MUFA, while nonbinge eating was significantly lower in percent energy from fat, SFA, and MUFA. Total intakes were significantly higher in energy and percent energy sucrose compared to the population. Despite significantly lower nonbinge energy intake, calcium, vitamins A and C, iron, and folate were not significantly different to the population median. However, one half or more of the subjects had less than two-thirds the RDA for nonbinge calcium, iron, zinc and for total intake one fourth remained less than two-thirds the RDA for iron and zinc. CONCLUSION: Nonbinge eating was characterized by low energy intake and by low intake of iron, calcium, and zinc. Binge eating, characterized by high sucrose and SFA content, overcompensated for these low energy intakes. Where treatment reduces or eliminates binge eating, it should also encourage consumption of regular meals and in particular, consumption of foods rich in zinc and iron.

Electromyographic activity of shoulder muscles during unilateral upper extremity proprioceptive neuromuscular facilitation patterns.

Twenty-nine normal adults were tested to measure the electrical activity of the anterior, middle, and posterior portions of the deltoid muscle and sternal portion of the pectoralis major muscle during the performance of four upper extremity diagonal patterns with the elbow straight, flexing, and extending. The patterns were performed through range of motion, with an isometric contraction performed in the shortened range. With the elbow straight, the middle portion of the deltoid muscle was primarily active with shoulder flexion, abduction, and external rotation; the anterior portion of the deltoid muscle with shoulder flexion, adduction, and external rotation; the posterior portion of the deltoid muscle with shoulder extension, abduction, and internal rotation; and the sternal portion of the pectoralis major muscle with shoulder extension, adduction, and internal rotation. The middle and anterior portions of the deltoid muscle exhibited significantly greater activity in their optimal patterns with the elbow strainght, followed by patterns with the elbow flexing and significantly less activity with the elbow extending. The posterior portion of the deltoid muscle in its optimal pattern produced greatest activity with the elbow straight or extending. Findings confirm the patterns considered optimal for monitored portions of these two muscles in normal subjects. Suggestions are made for study of patients who exhibit imbalances of muscle strength.