A Data-Driven Model with Hysteresis Compensation for I2RIS Robot

Retinal microsurgery is a high-precision surgery performed on an exceedingly delicate tissue. It now requires extensively trained and highly skilled surgeons. Given the restricted range of instrument motion in the confined intraocular space, and also potentially restricting instrument contact with the sclera, snake-like robots may prove to be a promising technology to provide surgeons with greater flexibility, dexterity, space access, and positioning accuracy during retinal procedures requiring high precision and advantageous tooltip approach angles, such as retinal vein cannulation and epiretinal membrane peeling. Kinematics modeling of these robots is an essential step toward accurate position control, however, as opposed to conventional manipulators, modeling of these robots does not follow a straightforward method due to their complex mechanical structure and actuation mechanisms. Especially, in wire-driven snake-like robots, the hysteresis problem due to the wire tension condition can have a significant impact on the positioning accuracy of these robots. In this paper, we proposed an experimental kinematics model with a hysteresis compensation algorithm using the probabilistic Gaussian mixture models (GMM) Gaussian mixture regression (GMR) approach. Experimental results on the two-degree-of-freedom (DOF) integrated robotic intraocular snake (I2RIS) show that the proposed model provides 0.4 deg accuracy, which is an overall 60% and 70% of improvement for yaw and pitch degrees of freedom, respectively, compared to a previous model of this robot

Patterns of Anti-Osteoporosis Medication Use among Women at High Risk of Fracture : Findings from the Global Longitudinal Study of Osteoporosis in Women (GLOW)

To assess patterns of anti-osteoporosis medication (AOM) use over 3 years among women at high risk of major fracture. The GLOW registry follows a cohort of more than 40,000 women aged ≥55 from 615 primary care practices in 10 countries. Self-administered surveys (baseline, 12, 24, and 36 months) collected data on patient characteristics, perception of fracture risk, and AOM use. FRAX scores were calculated from the baseline surveys and women classified as high risk if their FRAX 10-year probability of major fracture was ≥20%. A total of 5774 women were classified as at high risk and had complete data over 3 years. At baseline, 2271 (39%) reported receiving AOM, 739 (13%) reported prior but not current use, and 2764 (48%) said they had never used AOM. Over 3 years, 85% of baseline non-users continued as non-users and 15% initiated AOM; among baseline users, 49% continued the same medication class, 29% stopped AOM, and 12% switched. Women who stopped AOM were less likely to self-report osteoporosis (HR 0.56, 95% CI 0.42-0.75) than women who continued AOM. Compared with non-users who did not begin treatment, women initiating AOM were more likely to report a diagnosis of osteoporosis (HR 11.3, 95% CI 8.2-15.5) or osteopenia (HR 4.1, 95% CI 2.9-5.7) and be very concerned about osteoporosis (HR 1.9, 95% CI 1.3-2.8). Less than 40% of women at high risk of fracture reported taking AOM. Women who stopped AOM were less likely to believe they have osteoporosis. Women who initiated treatment appeared motivated primarily by a diagnosis of osteoporosis or osteopenia and concern about the condition

Patterns of anti-osteoporosis medication use among women at high risk of fracture: findings from the Global Longitudinal Study of Osteoporosis in Women (GLOW)

OBJECTIVE: To assess patterns of anti-osteoporosis medication (AOM) use over 3 years among women at high risk of major fracture. METHODS: The GLOW registry follows a cohort of more than 40,000 women aged \u3e /= 55 from 615 primary care practices in 10 countries. Self-administered surveys (baseline, 12, 24, and 36 months) collected data on patient characteristics, perception of fracture risk, and AOM use. FRAX scores were calculated from the baseline surveys and women classified as high risk if their FRAX 10-year probability of major fracture was \u3e /= 20%. RESULTS: A total of 5774 women were classified as at high risk and had complete data over 3 years. At baseline, 2271 (39%) reported receiving AOM, 739 (13%) reported prior but not current use, and 2764 (48%) said they had never used AOM. Over 3 years, 85% of baseline non-users continued as non-users and 15% initiated AOM; among baseline users, 49% continued the same medication class, 29% stopped AOM, and 12% switched. Women who stopped AOM were less likely to self-report osteoporosis (HR 0.56, 95% CI 0.42-0.75) than women who continued AOM. Compared with non-users who did not begin treatment, women initiating AOM were more likely to report a diagnosis of osteoporosis (HR 11.3, 95% CI 8.2-15.5) or osteopenia (HR 4.1, 95% CI 2.9-5.7) and be very concerned about osteoporosis (HR 1.9, 95% CI 1.3-2.8). CONCLUSIONS: Less than 40% of women at high risk of fracture reported taking AOM. Women who stopped AOM were less likely to believe they have osteoporosis. Women who initiated treatment appeared motivated primarily by a diagnosis of osteoporosis or osteopenia and concern about the condition

The Global Longitudinal Study of Osteoporosis in Women (GLOW): rationale and study design

SUMMARY: The Global Longitudinal study of Osteoporosis in Women (GLOW) is a prospective cohort study involving 723 physicians and 60,393 women subjects \u3eor=55 years. The data will provide insights into the management of fracture risk in older women over 5 years, patient experience with prevention and treatment, and distribution of risk among older women on an international basis. INTRODUCTION: Data from cohort studies describing the distribution of osteoporosis-related fractures and risk factors are not directly comparable and do not compare regional differences in patterns of patient management and fracture outcomes. METHODS: The GLOW is a prospective, multinational, observational cohort study. Practices typical of each region were identified through primary care networks organized for administrative, research, or educational purposes. Noninstitutionalized patients visiting each practice within the previous 2 years were eligible. Self-administered questionnaires were mailed, with 2:1 oversampling of women \u3eor=65 years. Follow-up questionnaires will be sent at 12-month intervals for 5 years. RESULTS: A total of 723 physicians at 17 sites in ten countries agreed to participate. Baseline surveys were mailed (October 2006 to February 2008) to 140,416 subjects. After the exclusion of 3,265 women who were ineligible or had died, 60,393 agreed to participate. CONCLUSIONS: GLOW will provide contemporary information on patterns of management of fracture risk in older women over a 5-year period. The collection of data in a similar manner in ten countries will permit comparisons of patient experience with prevention and treatment and provide insights into the distribution of risk among older women on an international basis

Using clinical risk factors and bone mineral density to determine who among patients undergoing bone densitometry should have vertebral fracture assessment

Vertebral fracture assessment (VFA) is a new method for imaging thoracolumbar spine on bone densitometer. Among patients referred for bone densitometry, the selection of patients for VFA testing can be optimized using an index derived from clinical risk factors and bone density measurement. VFA, a method for imaging thoracolumbar spine on bone densitometer, was developed because vertebral fractures, although common and predictive of future fractures, are often not clinically diagnosed. The study objective was to develop a strategy for selecting patients for VFA. A convenience sample from a university hospital bone densitometry center included 892 subjects (795 women) referred for bone mineral density (BMD) testing. We used questionnaires to capture clinical risk factors and dual-energy X-ray absorptiometry to obtain BMD and VFA. Prevalence of vertebral fractures was 18% in women and 31% in men (p = 0.003 for gender difference). In women, age, height loss, glucocorticoid use, history of vertebral and other fractures, and BMD T-score were significantly and independently associated with vertebral fractures. A multivariate model which included above predictors had an area under the receiver operating curve of 0.85 with 95% confidence interval (CI) of 0.81 to 0.89. A risk factor index was derived from the above multivariate model. Using a level of 2 as a cut-off yielded 93% sensitivity (95% CI 87, 96) and 48% specificity (95% CI 69, 83). Assuming a 15% prevalence of vertebral fractures, this cut-off value had a 24% positive and 97% negative predictive value and required VFA scanning of three women at a cost of $60 (assuming a$20 cost/VFA scan) to detect one with vertebral fracture(s). Selecting patients for VFA can be optimized using an index derived from BMD measurement and easily obtained clinical risk factors

When, where and how osteoporosis-associated fractures occur: An analysis from the global longitudinal study of osteoporosis in women (GLOW)

Objective: To examine when, where and how fractures occur in postmenopausal women. Methods: We analyzed data from the Global Longitudinal Study of Osteoporosis in Women (GLOW), including women aged ≥55 years from the United States of America, Canada, Australia and seven European countries. Women completed questionnaires including fracture data at baseline and years 1, 2 and 3. Results: Among 60,393 postmenopausal women, 4122 incident fractures were reported (86% non-hip, non-vertebral [NHNV], 8% presumably clinical vertebral and 6% hip). Hip fractures were more likely to occur in spring, with little seasonal variation for NHNV or spine fractures. Hip fractures occurred equally inside or outside the home, whereas 65% of NHNV fractures occurred outside and 61% of vertebral fractures occurred inside the home. Falls preceded 68-86% of NHNV and 68-83% of hip fractures among women aged ≤64 to ≥85 years, increasing with age. About 45% of vertebral fractures were associated with falls in all age groups except those ≥85 years, when only 24% occurred after falling. Conclusion: In this multi-national cohort, fractures occurred throughout the year, with only hip fracture having a seasonal variation, with a higher proportion in spring. Hip fractures occurred equally within and outside the home, spine fractures more often in the home, and NHNV fractures outside the home. Falls were a proximate cause of most hip and NHNV fractures. Postmenopausal women at risk for fracture need counseling about reducing potentially modifiable fracture risk factors, particularly falls both inside and outside the home and during all seasons of the year. © 2013 Costa et al

Climate change drives microevolution in a wild bird

To ensure long-term persistence, organisms must adapt to climate change, but an evolutionary response to a quantified selection pressure driven by climate change has not been empirically demonstrated in a wild population. Here, we show that pheomelanin-based plumage colouration in tawny owls is a highly heritable trait, consistent with a simple Mendelian pattern of brown (dark) dominance over grey (pale). We show that strong viability selection against the brown morph occurs, but only under snow-rich winters. As winter conditions became milder in the last decades, selection against the brown morph diminished. Concurrent with this reduced selection, the frequency of brown morphs increased rapidly in our study population during the last 28 years and nationwide during the last 48 years. Hence, we show the first evidence that recent climate change alters natural selection in a wild population leading to a microevolutionary response, which demonstrates the ability of wild populations to evolve in response to climate change