Design of a Minimum Surface-Effect Tendon-Based Microactuator for Micromanipulation

A piezoelectric (PZT) stack-based actuator was developed to provide a means of actuation with dynamic characteristics appropriate for small-scale manipulation. In particular, the design incorporates a highly nonlinear, large-ratio transmission that provides approximately two orders of magnitude motion amplification from the PZT stack. In addition to motion amplification, the nonlinear transmission was designed via optimization methods to distort the highly non-uniform properties of a piezoelectric actuator so that the achievable actuation force is nearly constant throughout the actuator workspace. The package also includes sensors that independently measure actuator output force and displacement, so that a manipulator structure need not incorporate sensors nor the associated wires. Specifically, the actuator was designed to output a maximum force of at least one Newton through a stroke of at least one millimeter. For purposes of small-scale precision position and/or force control, the actuator/sensor package was designed to eliminate stick-slip friction and backlash. The overall dimensions of the actuator/sensor package are approximately 40 x 65 x 25 mm

Privacy Regulation and Market Structure

This paper models how regulatory attempts to protect the privacy of consumers' data affect the competitive structure of data-intensive industries. Our results suggest that the commonly used consent-based approach may disproportionately benefit firms that offer a larger scope of services. Therefore, though privacy regulation imposes costs on all firms, it is small firms and new firms that are most adversely affected. We then show that this negative effect will be particularly severe for goods where the price mechanism does not mediate the effect, such as the advertising-supported Internet

Indirect costs associated with surgery for low back pain-a secondary analysis of clinical trial data.

This study examines the indirect costs associated with surgery for axial low back pain using data obtained from a prospective multicenter clinical trial that compared Charité artificial disc replacement with anterior lumbar interbody fusion using iliac crest bone graft. While 75% of study subjects reported full- or part-time employment prior to surgery, this percentage dropped to 45% at 6 weeks postoperatively. Return to preoperative employment levels occurred at approximately 6 months postoperatively. Two years after surgery, employment levels were 16% higher than preoperative levels. Lost productivity related to absenteeism resulted in lost wages averaging $2884 per patient during the first postoperative year. Although short-term indirect costs of surgery are substantial from a societal perspective, the higher employment rate at 2 years suggests a long-term economic benefit. The findings demonstrate the significant, though not surprising, impact of spinal disability on productivity, and the importance of including measurement of lost productivity and return to work in the economic evaluation of related interventions

Severe teratozoospermia and its influence on pronuclear morphology, embryonic cleavage and compaction

<p>Abstract</p> <p>Background</p> <p>Fertilization, cell division and embryo development depend on genomic contributions from male and female gametes. We hypothesize that teratozoospermic sperm influences early embryo development and embryo compaction.</p> <p>Methods</p> <p>We conducted a retrospective analysis of embryos derived from intracytoplasmic sperm injection (ICSI) cycles. Two hundred thirty-five consecutive ICSI cycles were included in the study; all treatment was provided at the Cleveland Clinic Fertility Center. Patient cycles were divided by sperm morphology based on Kruger's strict criteria: Group A, embryos where teratozoospermic sperm (0-2% normal) were used for ICSI and Group B, embryos where dysmorphic sperm (5-13% normal) were used for ICSI. All cycles analyzed were of patients doing day 3 embryo transfers. Outcome measures assessed included pronuclear (PN) pattern, syngamy, early cleavage, cell number, rate of compaction and blastulation of embryos left in culture and not transferred on day 3.</p> <p>Results</p> <p>A total of 1762 embryos were analyzed. PN patterns were similar in Group A and Group B embryos. No differences were noted in syngamy, cleavage, cell number or blastulation rate. Studying the development of embryos in culture after day 3 transfer revealed a difference in the timeline for compaction. By day 4, 25% of Group A embryos had compacted compared to 36% in Group B (P = 0.0007). There was no difference found between Group A and Group B embryos in regards to blastulation.</p> <p>Conclusions</p> <p>We did not find an association between sperm morphology and clinical outcomes. The impact of teratozoospermia may be masked in ICSI cycles where fertilization, implantation rate and clinical pregnancy rate are the primary outcome measures. However, by examining the timeline of development, we were better able to discern a potential paternal effect at critical transition points from fertilization through activation.</p

New social adaptability index predicts overall mortality

Introduction: Definitions of underprivileged status based on race, gender and geographic location are neither sensitive nor specific; instead we proposed and validated a composite index of social adaptability (SAI). Material and methods: Index of social adaptability was calculated based on employment, education, income, marital status, and substance abuse, each factor contributing from 0 to 3 points. Index of social adaptability was validated in NHANES-3 by association with all-cause and cause-specific mortality. Results: Weighted analysis of 19,593 subjects demonstrated mean SAI of 8.29 (95% CI 8.17-8.40). Index of social adaptability was higher in Whites, followed by Mexican-Americans and then the African-American population (ANOVA, p < 0.001). The SAI was higher in subjects living in metropolitan compared to rural areas (T-test, p < 0.001), and was greater in men than in women (T-test, p < 0.001). In Cox models adjusted for age, comorbidity index, BMI, race, sex, geographic location, hemoglobin, serum creatinine, albumin, cholesterol, and glycated hemoglobin levels, SAI was inversely associated with mortality (HR 0.87 per point, 95% CI 0.84-0.90, p < 0.001). This association was confirmed in subgroups. Conclusions: We proposed and validated an indicator of social adaptability with a strong association with mortality, which can be used to identify underprivileged populations at risk of death