Cognitive vision system for control of dexterous prosthetic hands: Experimental evaluation

<p>Abstract</p> <p>Background</p> <p>Dexterous prosthetic hands that were developed recently, such as SmartHand and i-LIMB, are highly sophisticated; they have individually controllable fingers and the thumb that is able to abduct/adduct. This flexibility allows implementation of many different grasping strategies, but also requires new control algorithms that can exploit the many degrees of freedom available. The current study presents and tests the operation of a new control method for dexterous prosthetic hands.</p> <p>Methods</p> <p>The central component of the proposed method is an autonomous controller comprising a vision system with rule-based reasoning mounted on a dexterous hand (CyberHand). The controller, termed cognitive vision system (CVS), mimics biological control and generates commands for prehension. The CVS was integrated into a hierarchical control structure: 1) the user triggers the system and controls the orientation of the hand; 2) a high-level controller automatically selects the grasp type and size; and 3) an embedded hand controller implements the selected grasp using closed-loop position/force control. The operation of the control system was tested in 13 healthy subjects who used Cyberhand, attached to the forearm, to grasp and transport 18 objects placed at two different distances.</p> <p>Results</p> <p>The system correctly estimated grasp type and size (nine commands in total) in about 84% of the trials. In an additional 6% of the trials, the grasp type and/or size were different from the optimal ones, but they were still good enough for the grasp to be successful. If the control task was simplified by decreasing the number of possible commands, the classification accuracy increased (e.g., 93% for guessing the grasp type only).</p> <p>Conclusions</p> <p>The original outcome of this research is a novel controller empowered by vision and reasoning and capable of high-level analysis (i.e., determining object properties) and autonomous decision making (i.e., selecting the grasp type and size). The automatic control eases the burden from the user and, as a result, the user can concentrate on what he/she does, not on how he/she should do it. The tests showed that the performance of the controller was satisfactory and that the users were able to operate the system with minimal prior training.</p

Impaired leukocyte influx in cervix of postterm women not responding to prostaglandin priming

<p>Abstract</p> <p>Background</p> <p>Prolonged pregnancies are associated with increased rate of maternal and fetal complications. Post term women could be divided into at least two subgroups, one where parturition is possible to induce by prostaglandins and one where it is not. Our aim was to study parameters in cervical biopsies in women with spontaneous delivery at term (controls) and compare to those that are successfully induced post term (responders), and those that are not induced (non-responders), by local prostaglandin treatment.</p> <p>Methods</p> <p>Stromal parameters examined in this study were the accumulation of leukocytes (CD45, CD68), mRNAs and/or proteins for the extracellular matrix degrading enzymes (matrix metalloproteinase (MMP)-2, MMP-8 and MMP-9), their inhibitors (tissue inhibitor of MMP (TIMP)-1 and TIMP-2), interleukin-8 (IL-8), the platelet activating factor-receptor (PAF-R), syndecan-1 and estrogen binding receptors (estrogen receptor (ER)α, ERβ and G-coupled protein receptor (GPR) 30) as well as the proliferation marker Ki-67.</p> <p>Results</p> <p>The influx of leukocytes as assessed by CD45 was strongest in the responders, thereafter in the controls and significantly lower in the non-responders. IL-8, PAF-R and MMP-9, all predominantly expressed in leukocytes, showed significantly reduced immunostaining in the group of non-responders, while ERα and GPR30 were more abundant in the non-responders, as compared to the controls.</p> <p>Conclusion</p> <p>The impaired leukocyte influx, as reflected by the reduced number of CD45 positive cells as well as decreased immunostaining of IL-8, PAF-R and MMP-9 in the non-responders, could be one explanation of the failed ripening of the cervix in post term women. If the decreased leukocyte influx is a primary explanation to absent ripening or secondary, as a result of other factors, is yet to be established.</p

If nuchal translucency screening is combined with first-trimester serum screening the need for fetal karyotyping decreases

Background. This case-control study was performed to evaluate whether adding first-trimester maternal serum testing to nuchal translucency measurement would improve the antenatal detection of Down's syndrome and decrease the number of women offered fetal karyotyping. Methods. In the Swedish Nuchal Translucency Trial 39,572 pregnant women were randomized to a routine scan at 12-14 gestational weeks including nuchal translucency screening for Down's syndrome, or a routine scan at 16-18 gestational weeks. From the early scan group 47 pregnancies with Down's syndrome were identified and for each case three controls were chosen. Of 189 women asked to participate, 31 cases and 108 controls with a singleton pregnancy and frozen sample from 8-14 gestational weeks available for analysis accepted participation. Maternal sera were analyzed for free beta human chorionic gonadotrophin and pregnancy-associated plasma protein A. The risk for Down's syndrome was calculated using combinations of maternal age, crown-rump length, nuchal translucency, and biochemistry. A risk >= 1/250 was considered increased and an indication for fetal karyotyping. Results. Risk calculated on the basis of maternal age alone would have identified 21 of the 31 Down's syndrome cases by karyotyping 61 of the 139 fetuses. Maternal age and nuchal translucency would have identified 29 cases by karyotyping 51 fetuses. Maternal age, nuchal translucency, and biochemistry would also have identified 29 cases by karyotyping 37 fetuses. Conclusions. By adding first trimester biochemistry to nuchal translucency measurement the detection rate of fetuses with Down's syndrome seems to remain unchanged whereas the antenatal risk group to be offered fetal karyotyping decreases

By how much does increased nuchal translucency increase the risk of adverse pregnancy outcome in chromosomally normal fetuses? A study of 16 260 fetuses derived from an unselected pregnant population.

Objective: In this study we aimed to estimate the magnitude of a possible increase in risk of adverse outcome in fetuses with normal karyotype and increased nuchal translucency (NT), and to determine bow well NT measurements can distinguish between fetuses with normal and adverse outcome. Methods: We studied 16260 consecutive fetuses with normal karyotype derived from an unselected pregnant population. The following cut-offs for increased risk of adverse outcome were chosen a priori: NT >= 95(th) percentile, >= 3 mm, >= 3.5 mm, and >= 4.5 mm. The positive and negative likelihood ratios (+LR, -LR) of the risk cut-offs with regard to fetal malformation, miscarriage, perinatal death, termination of pregnancy and total adverse outcome were calculated, and receiver-operating characteristics (ROC) curves were drawn. Results: The total rate of adverse outcome was 2.7%. +LR and -LR of NT >= 3.0 mm were: for lethal or severe malformation, +LR 15.0 (95% CI 7.0-28.6), -LR 0.89 (95% CI 0.81-0.9S); for malformation of at least intermediate severity, +LR 8.1 (95% CI 4.3-14.0), -LR 0.95 (95% CI 0.92-0.97); for termination of pregnancy, +LR 41.6 (95% CI 17.1-86.6), -LR 0.67 (95% CI 0.41-0.85); for any adverse outcome, +LR 6.4 (95% CI 3.4-11), -LR 0.96 (95% CI 0.94-0.98). The odds for these adverse outcomes increased with increasing NT. NT >= 3 mm did not significantly increase the risk of miscarriage or perinatal death. Areas under ROC curves for NT were small, with 95% CI below or only slightly above 0.5. Conclusion: Our likelihood ratios can be used to calculate the individual risk of unfavorable outcome, but NT screening cannot reliably distinguish between normal and adverse outcome in fetuses with normal karyotype. Copyright (c) 2007 ISUOG. Published by John Wiley & Sons, Ltd

Progress of a modular prosthetic arm

About the book: There is an ever-increasing need for designers to create products that are genuinely inclusive of members of society with special needs. The population is growing older and legislative demands on industry to provide equal access for all are growing ever more stringent. Several research disciplines are working to find solutions to the problem of how to develop more inclusive products and the aim of Universal Access and Assistive Technology is to bring experiences from these different perspectives into a single reference. This book contains the proceedings of the first Cambridge Workshop on Universal Access and Assistive Technology (CWUAAT), incorporating the fourth Cambridge Workshop on Rehabilitation Robotics, held in Cambridge, England in March 2002. This book contains contributions from an international group of leading researchers in the fields of Universal Access and Assistive Technology. Contributions include papers on design, robotics and computer access, as well as the experiences of industry. It is composed of three parts containing material on: design issues for universal access and assistive technology; enabling computer access and new technologies; assistive technology and rehabilitation robotics. Reflecting the spirit of recent moves to extend rights to universal accessibility, this series of workshops and accompanying books is aimed at a broad range of interests, with a general focus on the development of products and solutions. Numerous case studies are used to raise awareness of the challenges faced in developing truly inclusive products, along with examples of good practice