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Existing techniques that convert B-rep (boundary representation) patches into Clough-Tocher splines guarantee watertight, that is C 0 , conversion results across B-rep edges. In contrast, our approach ensures global tangent-plane, that is G 1 , continuity of the converted B-rep CAD models. We achieve this by careful boundary curve and normal vector management, and by converting the input models into Shirman-Sequin macro-elements near their (trimmed) B-rep edges. We propose several different variants and compare them with respect to their locality, visual quality, and difference with the input B-rep CAD model. Although the same global G 1 continuity can also be achieved by conversion techniques based on subdivision surfaces, our approach uses triangular splines and thus enjoys full compatibility with CAD.

Introduction and hypothesis The use of synthetic mesh in transvaginal pelvic floor surgery has been subject to debate internationally. Although mesh erosion appears to be less associated with an abdominal approach, the long-term outcome has not been studied intensively. This study was set up to determine the long-term mesh erosion rate following abdominal pelvic reconstructive surgery. Methods A prospective, observational cohort study was conducted in a tertiary care setting. All consecutive female patients who underwent robot-assisted laparoscopic sacrocolpopexy and sacrocolporectopexy in 2011 and 2012 were included. Primary outcome was mesh erosion. Preoperative and postoperative evaluation (6 weeks, 1 year, 5 years) with a clinical examination and questionnaire regarding pelvic floor symptoms was performed. Mesh-related complications were assessed using a transparent vaginal speculum, proctoscopy, and digital vaginal and rectal examination. Kaplan–Meier estimates were calculated for mesh erosion. A review of the literature on mesh exposure after minimally invasive sacrocolpopexy was performed (≥12 months’ follow-up). Results Ninety-six of the 130 patients included (73.8%) were clinically examined. Median follow-up time was 48.1 months (range 36.0–62.1). Three mesh erosions were diagnosed (3.1%; Kaplan–Meier 4.9%, 95% confidence interval 0–11.0): one bladder erosion for which mesh resection and an omental patch interposition were performed, and two asymptomatic vaginal erosions (at 42.7 and 42.3 months) treated with estrogen cream in one. Additionally, 22 patients responded solely by questionnaire and/or telephone; none reported mesh-related complaints. The literature, mostly based on retrospective studies, described a median mesh erosion rate of 1.9% (range 0–13.3%). Conclusions The long-term rate of mesh erosion following an abdominally placed synthetic graft is low. Electronic supplementary material The online version of this article (10.1007/s00192-019-03990-1) contains supplementary material, which is available to authorized users

Background Endovascular iliac artery interventions rely on the use of two-dimensional digital subtraction angiographies with an iodinated contrast agent and ionizing radiation. The amount of iodinated contrast agent should be limited because of its potentially nephrotoxic effects. Three-dimensional (3D) image fusion requires registration of a preprocedural magnetic resonance angiogram (MRA) or computed tomography (CT) angiogram to a perprocedurally acquired cone-beam CT or two fluoroscopic orthogonal projections. After registration, the 3D angiography images can be overlaid on the fluoroscopy screen and will follow table and C-arm movements. This study will assess the added value of the 3D image fusion technique in iliac artery interventions regarding the amount of the iodinated contrast agent administered. Methods/Design The study cohort will comprise 106 patients (> 18 years) with symptomatic common and/or external iliac artery stenoses or occlusions and a recent (

Gradient mesh design tools allow users to create detailed scalable images, traditionally through the creation and manipulation of a (dense) mesh with regular rectangular topology. Through recent advances it is now possible to allow gradient meshes to have arbitrary manifold topology, using a modified Catmull-Clark subdivision scheme to define the resultant geometry and colour [LKSD17]. We present two novel methods to allow local and hierarchical refinement of both colour and geometry for such subdivision gradient meshes. Our methods leverage the mesh properties that the particular subdivision scheme ensures. In both methods, the artists enjoy all the standard capabilities of manipulating the mesh and the associated colour gradients at the coarsest level as well as locally at refined levels. Further novel features include interpolation of both position and colour of the vertices of the input meshes, local detail follows coarser-level edits, and support for sharp colour transitions, all at any level in the hierarchy offered by subdivision.

Objective: Aortic pulse-wave-velocity (aPWV) is a measure for arterial stiffness, which is associated with increased cardiovascular risk. Recent evidence suggests aPWV increases after endograft-placement for aortic aneurysms. The aim of this study was to investigate the influence of different aortic endoprostheses on aPWV and structural stiffness in vitro. Approach: Three different abdominal aortic endoprostheses (AFX, Endurant II, and Nellix) were implanted in identical silicone aneurysm models. One model was left untreated, and another model contained an aortic tube graft (Gelweave). The models were placed in an in vitro flow set-up that mimics physiological flow. aPWV was measured as the transit time of the pressure wave over the flow trajectory of the suprarenal to iliac segment. Structural stiffness corrected for lumen diameter was calculated for each model. Results: aPWV was significantly lower for the control compared to the AFX, Endurant, Nellix and tube graft models (13.00 +/- 1.20,13.40 +/- 1.17,18.18 +/- 1.20,16.19 +/- 1.25 and 15.41 +/- 0.87 m s(-1), respectively (P

Information from multiple modalities contributes to recognizing emotions. While it is known interactions occur between modalities, it is unclear what characterizes these. These interactions, and changes in these interactions due to sensory impairments, are the main subject of this PhD project. This extended abstract for the Doctoral Symposium of ETRA 2018 describes the project; its background, what I hope to achieve, and some preliminary results.

The invention is directed to a method and a surgical instrument, typically a surgical stapler that is configured for performing anastomosis of a first gastro-intestinal tract section to a second gastro-intestinal tract section, both gastro-intestinal tract sections comprising a superficial layer and an intermediate layer. Said method comprises contacting the superficial layers of said gastro-intestinal tract sections and compressing the contacted sections between a first pressure area and a second pressure area, wherein the sum of the first pressure area and the second pressure increases during the compression such that the superficial layers are pressed aside and the intermediate layers are contacted.

In adult normal-hearing musicians, perception of music, vocal emotion, and speech in noise has been previously shown to be better than non-musicians, sometimes even with spectro-temporally degraded stimuli. In this study, melodic contour identification, vocal emotion identification, and speech understanding in noise were measured in young adolescent normal-hearing musicians and non-musicians listening to unprocessed or degraded signals. Different from adults, there was no musician effect for vocal emotion identification or speech in noise. Melodic contour identification with degraded signals was significantly better in musicians, suggesting potential benefits from music training for young cochlear-implant users, who experience similar spectro-temporal signal degradations.

Prostate cancer is one of the leading causes of death in men. Prostate interventions using magnetic resonance imaging (MRI) benefits from high tissue contrast if compared to other imaging modalities. The Minimally Invasive Robotics In An MRI environment (MIRIAM) robot is an MRI-compatible system able to steer different types of needles towards a point of interest using MRI guidance. However, clinicians can be reluctant to give the robot total control of the intervention. This work integrates a haptic device in the MIRIAM system to allow input from the clinician during the insertion. A shared control architecture is achieved by letting the clinician control the insertion depth via the haptic device, while the robotic system controls the needle orientation. The clinician receives haptic feedback based on the insertion depth and tissue characteristics. Four control laws relating the motion of the master robot (haptic device) to the motion of the slave robot (MIRIAM robot) are presented and evaluated. Quantitative and qualitative results from 20 human subjects demonstrate that the squared-velocity control law is the most suitable option for our application. Additionally, a pre-operative target localization algorithm is presented in order to provide the robot with the target location. The target localization and reconstruction algorithm are validated in phantom and patient images with an average dice similarity coefficient (DSC) of 0.78. The complete system is validated through experiments by inserting a needle towards a target within the MRI scanner. Four human subjects perform the experiment achieving an average targeting error of 3.4[Formula: see text]mm.

Speech signals delivered via cochlear implants (CIs) lack spectro-temporal details, yet, young-implanted children can develop good native language skills (L1). This study explores three research questions: 1. Can adolescents with CIs learn a second language (L2)? 2. Is there a difference in spoken (auditory-A) vs. written (visual-V) L2 skills? 3. Which perceptual and cognitive factors influence L2 learning? Two groups (L1 = Dutch, age 12—17 years), one with normal hearing (NH) and one with CIs, and both learning English (L2) at school, participated. L1 and L2 proficiency was measured in receptive vocabulary (A), comprehension (A, V), and general proficiency (V). Further, basic auditory functioning, in temporal (gap detection) and spectral (spectral ripple detection) resolution, and cognitive functioning, in IQ, working memory, and attention, were measured. Preliminary data (n = 7 per group) indicated comparable L1 proficiency between NH and CI groups. While some CI users showed L2 proficiency within the NH range, on average, L2 proficiency was lower for the CI group. This effect was more pronounced for auditory tests. Reduced temporal and spectral resolution, but no difference in cognitive tests, were observed in CI group compared to NH, emphasizing the importance of auditory factors in L2 learning.

In normal-hearing (NH) adults, long-term music training may benefit music and speech perception, even when listening to spectro-temporally degraded signals as experienced by cochlear implant (CI) users. In this study, we compared two different music training approaches in CI users and their effects on speech and music perception, as it remains unclear which approach to music training might be best. The approaches differed in terms of music exercises and social interaction. For the pitch/timbre group, melodic contour identification (MCI) training was performed using computer software. For the music therapy group, training involved face-to-face group exercises (rhythm perception, musical speech perception, music perception, singing, vocal emotion identification, and music improvisation). For the control group, training involved group nonmusic activities (e.g., writing, cooking, and woodworking). Training consisted of weekly 2-hr sessions over a 6-week period. Speech intelligibility in quiet and noise, vocal emotion identification, MCI, and quality of life (QoL) were measured before and after training. The different training approaches appeared to offer different benefits for music and speech perception. Training effects were observed within-domain (better MCI performance for the pitch/timbre group), with little cross-domain transfer of music training (emotion identification significantly improved for the music therapy group). While training had no significant effect on QoL, the music therapy group reported better perceptual skills across training sessions. These results suggest that more extensive and intensive training approaches that combine pitch training with the social aspects of music therapy may further benefit CI users.

Electroencephalographic (EEG) recordings provide objective estimates of listeners' cortical processing of sounds and of the status of their speech perception system. For profoundly deaf listeners with cochlear implants (CIs), the applications of EEG are limited because the device adds electric artifacts to the recordings. This restricts the possibilities for the neural-based metrics of speech processing by CI users, for instance to gauge cortical reorganization due to individual's hearing loss history. This paper describes the characteristics of the CI artifact as recorded with an artificial head substitute, and reports how the artifact is affected by the properties of the acoustical input signal versus the settings of the device.METHODS: We created a brain substitute using agar that simulates the brain's conductivity, placed it in a human skull, and performed EEG recordings with CIs from three different manufacturers. As stimuli, we used simple and complex non-speech stimuli, as well as naturally produced continuous speech. We examined the effect of manipulating device settings in both controlled experimental CI configurations and real clinical maps.RESULTS: An increase in the magnitude of the stimulation current through the device settings increases also the magnitude of the artifact. The artifact recorded to speech is smaller in magnitude than for non-speech stimuli due to signal-inherent amplitude modulations.CONCLUSION: The CI EEG artifact for speech appears more difficult to detect than for simple stimuli. Since the artifact differs across CI users, due to their individual clinical maps, the method presented enables insight into the individual manifestations of the artifact.

International audience; Objectives: When listening to two competing speakers, normal-hearing (NH) listeners can take advantage of voice differences between the speakers. Users of cochlear implants (CIs) have difficulty in perceiving speech on speech. Previous literature has indicated sensitivity to voice pitch (related to fundamental frequency, F0) to be poor among implant users, while sensitivity to vocal-tract length (VTL; related to the height of the speaker and formant frequencies), the other principal voice characteristic , has not been directly investigated in CIs. A few recent studies evaluated F0 and VTL perception indirectly, through voice gender cat-egorization, which relies on perception of both voice cues. These studies revealed that, contrary to prior literature, CI users seem to rely exclusively on F0 while not utilizing VTL to perform this task. The objective of the present study was to directly and systematically assess raw sensitivity to F0 and VTL differences in CI users to define the extent of the deficit in voice perception. Design: The just-noticeable differences (JNDs) for F0 and VTL were measured in 11 CI listeners using triplets of consonant-vowel syllables in an adaptive three-alternative forced choice method. Results: The results showed that while NH listeners had average JNDs of 1.95 and 1.73 semitones (st) for F0 and VTL, respectively, CI listeners showed JNDs of 9.19 and 7.19 st. These JNDs correspond to differences of 70% in F0 and 52% in VTL. For comparison to the natural range of voices in the population, the F0 JND in CIs remains smaller than the typical male-female F0 difference. However, the average VTL JND in CIs is about twice as large as the typical male-female VTL difference. Conclusions: These findings, thus, directly confirm that CI listeners do not seem to have sufficient access to VTL cues, likely as a result of limited spectral resolution, and, hence, that CI listeners' voice perception deficit goes beyond poor perception of F0. These results provide a potential common explanation not only for a number of deficits observed in CI listeners, such as voice identification and gender categorization, but also for competing speech perception.

Microrobotics is a promising field that can revolutionize fields such as minimally invasive surgery. Applications such as micromanipulation can be performed more effectively using multiple microsized agents. These can be performed more accurately with the help of robust controllers. In this letter, we design a leader–follower controller that can be used to perform coordinated motion tasks. A prescribed performance controller is designed for the leader micro-agent whereas a synchronization controller is designed for the follower. The main difference between our method and the literature is that our method can achieve a prespecified control performance. The positions of the micro-agents are obtained using microscopic images and image processing. The velocities and accelerations of the micro-agents are obtained using state observers. The algorithm is tested experimentally on spherical magnetic microparticles that have an average diameter of 100 $\mu{\text{m}}$ . Two types of experiments are performed. The first one is related to the leader–follower control, whereas the second one demonstrates the independent control of the two agents. The maximum value of the steady-state errors obtained in the leader–follower control experiments are 14.45 $\mu{\text{m}}$ and 10.19 $\mu{\text{m}}$ in the x-and y-directions for the leader agent and 6.47 $\mu{\text{m}}$ and 7.77 $\mu{\text{m}}$ in the x-and y-directions for the follower errors, respectively.

In this paper we present three distributed control laws for the coordination of networked Euler-Lagrange (EL) systems. We first reformulate the passivity-based control design method in \cite{Arcak} by considering that each edge is associated with an \emph{artificial spring system} instead of the usual diffusive coupling among the communicating agents. With this configuration, the networked EL system possesses a "symmetric" feedback structure which together with the strict passivity of both agents' and edges' dynamics lead to a strictly passive network dynamics. Subsequently we present the networked version of two different passivity-based tracking controllers %local controllers that are particular cases of our method and the one in \cite{Arcak}. Numerical simulation is presented to show the performance of the proposed methods., Comment: Submitted to Necsys2018, 7 pages, 1 figure

In recent years, wave energy converters (WECs) have received considerable attention as an efficient way to harvest alternative energy sources. Within this class of systems, point-absorbers are popular and have become one of the most widely used renewable energy harvest designs all over the world, at least in the preliminary R&D stage, with many relevant research works having been published as well. However, unlike the single buoy and PTO systems which already have a comprehensive research basis, the connection cable has received little attention. The traditional taut cable analysis approach, initiated from the needs of the oil&gas industry, has been applied for WEC investigations. However, this approach utilizes an essential assumption that the oscillating term (PTO force) is much smaller than the static term of the cable force (pre-tension) and could be neglected, which may not be proper for WEC applications. In this work, a conventional frequency domain model is utilized to test and verify the validity of the previously mentioned assumption by presenting the ratio between two force terms. Then the ratio could be applied in combination with sea state contours to reveal the critical state of the cable. Then, a fully nonlinear time domain method of a numerical solution of the point-absorber wave energy converter is presented. According to the critical states obtained from the frequency domain analysis, an improved model of a slack cable is proposed. Its influence on the energy extraction performance is investigated using the open source code — WEC-Sim. This work provides insight into simulating a proper model of the cable and how the design of the cable influences the WEC performance.

Based on recent advances in contraction methods in systems and control, in this paper we present the virtual differential passivity based control (v-dPBC) technique. This is a constructive design method that combines the concept of virtual systems and of differential passivity. We apply the method to the tracking control problem of flexible joints robots (FJRs) which are formulated in the port-Hamiltonian (pH) framework. Simulations on a single flexible joint link are presented for showing the performance of a controller obtained with this approach., Comment: 8 pages, 2 figures, submitted to Workshop on Lagrangian and Hamiltonian Methods in Nonlinear Control 2018

Contains fulltext : 181861.pdf (Publisher’s version ) (Closed access) BACKGROUND: Infected necrotising pancreatitis is a potentially lethal disease and an indication for invasive intervention. The surgical step-up approach is the standard treatment. A promising alternative is the endoscopic step-up approach. We compared both approaches to see whether the endoscopic step-up approach was superior to the surgical step-up approach in terms of clinical and economic outcomes. METHODS: In this multicentre, randomised, superiority trial, we recruited adult patients with infected necrotising pancreatitis and an indication for invasive intervention from 19 hospitals in the Netherlands. Patients were randomly assigned to either the endoscopic or the surgical step-up approach. The endoscopic approach consisted of endoscopic ultrasound-guided transluminal drainage followed, if necessary, by endoscopic necrosectomy. The surgical approach consisted of percutaneous catheter drainage followed, if necessary, by video-assisted retroperitoneal debridement. The primary endpoint was a composite of major complications or death during 6-month follow-up. Analyses were by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN09186711. FINDINGS: Between Sept 20, 2011, and Jan 29, 2015, we screened 418 patients with pancreatic or extrapancreatic necrosis, of which 98 patients were enrolled and randomly assigned to the endoscopic step-up approach (n=51) or the surgical step-up approach (n=47). The primary endpoint occurred in 22 (43%) of 51 patients in the endoscopy group and in 21 (45%) of 47 patients in the surgery group (risk ratio [RR] 0.97, 95% CI 0.62-1.51; p=0.88). Mortality did not differ between groups (nine [18%] patients in the endoscopy group vs six [13%] patients in the surgery group; RR 1.38, 95% CI 0.53-3.59, p=0.50), nor did any of the major complications included in the primary endpoint. INTERPRETATION: In patients with infected necrotising pancreatitis, the endoscopic step-up approach was not superior to the surgical step-up approach in reducing major complications or death. The rate of pancreatic fistulas and length of hospital stay were lower in the endoscopy group. The outcome of this trial will probably result in a shift to the endoscopic step-up approach as treatment preference. FUNDING: The Dutch Digestive Disease Foundation, Fonds NutsOhra, and the Netherlands Organization for Health Research and Development.

In this work, a frequency-domain method for the numerical solution of the nonlinear dynamics of a wave energy converter with a pumping system is presented. To this end, a finite Fourier series is used to describe the nonlinear force components, i.e., the pumping force. The dynamics of the buoy and the piston are obtained by solving a set of linear motion equations. The numerical model is validated by comparing it with experimental results. The dynamic characteristics of the pumping system are investigated by performing a series of numerical simulations for several approximation orders under various wave conditions. The advantages and limitations of this method are also discussed in the paper. This work provides great insight into the mechanism of a WEC with a pumping unit under various sea states, which can guide the design of a multi-piston pump (MPP) system. This model will be applied to investigate the optimal configuration for the MPP system in the future.

We present a distributed control law for a group of agents that solves the problem of formation control with obstacle avoidance and that can be combined with a coordinated group stabilization control law. In particular, we consider a control law that is given by a linear combination of distributed formation, distributed obstacle avoidance and centralized group motion control laws. Simulation results show the effectiveness of our proposed control law.

Effective collaborative work in diagnostic medical imaging is not trivial due to the large amounts of complex data involved, a (non-linear) workflow involving experts in different domains, and a lack of versatility in the current tools employed in healthcare. In this paper, we aim to introduce how the integration of visual storytelling techniques together with provenance data in the analytic systems used in medicine can compensate for these issues, by enhancing communication of results and reproducibility of findings through diagnostic provenance data. To this end, we illustrate how we can improve the interaction with provenance data displayed in a graph in order to facilitate authoring and the creation process of visual data stories

In context of wavefront control for high-contrast coronagraphy, we present the spectral characterization of speckles generated by deformable mirrors (DMs) at various distances downstream of the pupil plane. We have measured the focal-plane electric field at 600 to 690nm of speckles generated with an in- and out-of-pupil DM on a high- contrast testbed using a self-coherent camera. These measurements are analyzed analytically and are compared to numerical end-to-end simulations of the setup. This will aid in the design of wavefront correction algorithms with multiple DMs.

We introduce a new approach to numerical quadrature on geometries defined by subdivision surfaces based on quad meshes in the context of isogeometric analysis. Starting with a sparse control mesh, the subdivision process generates a sequence of finer and finer quad meshes that in the limit defines a smooth subdivision surface, which can be of any manifold topology. Traditional approaches to quadrature on such surfaces rely on per-quad integration, which is inefficient and typically also inaccurate near vertices where other than four quads meet. Instead, we explore the space of possible groupings of quads and identify the optimal macro-quads in terms of the number of quadrature points needed. We show that macro-quads consisting of quads from one or several consecutive levels of subdivision considerably reduce the cost of numerical integration. Our rules possess a tensor product structure and the underlying univariate rules are Gaussian, i.e., they require the minimum possible number of integration points in both univariate directions. The optimal quad groupings differ depending on the particular application. For instance, computing surface areas, volumes, or solving the Laplace problem lead to different spline spaces with specific structures in terms of degree and continuity. We show that in most cases the optimal groupings are quad-strips consisting of ( 1 × n ) quads, while in some cases a special macro-quad spanning more than one subdivision level offers the most economical integration. Additionally, we extend existing results on exact integration of subdivision splines. This allows us to validate our approach by computing surface areas and volumes with known exact values. We demonstrate on several examples that our quadratures use fewer quadrature points than traditional quadratures. We illustrate our approach to subdivision spline quadrature on the well-known Catmull–Clark scheme based on bicubic splines, but our ideas apply also to subdivision schemes of arbitrary bidegree, including non-uniform and hierarchical variants. Specifically, we address the problems of computing areas and volumes of Catmull–Clark subdivision surfaces, as well as solving the Laplace and Poisson PDEs defined over planar unstructured quadrilateral meshes in the context of isogeometric analysis.

Needle insertion procedures under ultrasound guidance are commonly used for diagnosis and therapy. It is often critical to accurately reach a targeted region, and this can be difficult to achieve due to intraoperative tissue motion. In this letter, we present a method to steer a beveled-tip flexible needle toward a target embedded in moving tissue. Needle steering is performed using a needle insertion device attached to a robot arm. Closed-loop 3-D steering of the needle is achieved using tracking of an artificial target in 2-D ultrasound images and tracking of the needle tip position and orientation with an electromagnetic tracker. Tissue motion compensation is performed using force feedback to reduce targeting error and forces applied to the tissue. The method uses a mechanics-based interaction model that is updated online. A novel control law using task functions is proposed to fuse motion compensation, steering via base manipulation and tip-based steering. Validation of the tracking and steering algorithms are performed in gelatin phantom and bovine liver. Tissue motion up to 15 mm is applied and average targeting error is 1.2 $\pm$ 0.8 mm and 2.5 $\pm$ 0.7 mm in gelatin and liver, respectively, which is sufficiently accurate for commonly performed needle insertion procedures.

Several studies have shown that musicians may have an advantage in a variety of auditory tasks, including speech in noise perception. The current study explores whether musical training enhances understanding two-talker masked speech. By combining an off-line and an on-line measure of speech perception, we investigated how automatic processes can contribute to the potential perceptual advantage of musicians. Understanding the underlying mechanisms for how musical training may lead to a benefit in speech-in-noise perception could help clinicians in developing ways to use music as a means to improve speech processing of hearing impaired individuals.

We study a control design problem for nonlinear affine systems whose initial condition is a random variable with known distribution. In this control problem, the control objectives are two-folds: (i). the closed-loop system attains a minimum cumulative distribution over a prescribed containment set at the end of transient time; and (ii) it converges exponentially to a desired trajectory. A solution to the control problem is obtained by imposing desired contraction properties on the closed-loop system such that both control objectives can be met. The efficacy of the proposed controller design is shown on the control of robotic manipulator.

In this paper, we study integral regulation mechanism in a class of phosphorylation cycles where we consider enzyme regulation by an intermediary metabolite. Using chemical reaction network framework, we prove that the network dynamics is (locally) asymptotically stable for sufficiently small integral gain. Furthermore, we show that the integral regulation ensures the absolute concentration robustness (ACR) property of the network.

Early prostate cancer detection and treatment are of major importance to reduce mortality rate. magnetic resonance (MR) imaging provides images of the prostate where an early stage lesion can be visualized. The use of robotic systems for MR-guided interventions in the prostate allows us to improve the clinical outcomes of procedures such as biopsy and brachytherapy. This work presents a novel MR-conditional robot for prostate interventions. The minimally invasive robotics in an magnetic resonance imaging environment (MIRIAM) robot has 9 degrees-of-freedom (DoF) used to steer and fire a biopsy needle. The needle guide is positioned against the perineum by a 5 DoF parallel robot driven by piezoelectric motors. A 4 DoF needle driver inserts, rotates and fires the needle during the procedure. Piezoelectric motors are used to insert and rotate the needle, while pneumatic actuation is used to fire the needle. The MR-conditional design of the robot and the needle insertion controller are presented. MR compatibility tests using T2 imaging protocol are performed showing a SNR reduction of 25% when the robot is operational within the MR scanner. Experiments inserting a biopsy needle toward a physical target resulted in an average targeting error of 1.84[Formula: see text]mm. Our study presents a novel MR-conditional robot and demonstrated the ability to perform MR-guided needle-based interventions in soft-tissue phantoms. Moreover, the image distortion analysis indicates that no visible image deterioration is induced by the robot.

This study compares two response-time measures of listening effort that can be combined with a clinical speech test for a more comprehensive evaluation of total listening experience; verbal response times to auditory stimuli (RTaud) and response times to a visual task (RTsvis) in a dual- task paradigm. The listening task was presented in five masker conditions; no noise, and two types of noise at two fixed intelligibility levels. Both the RTsaud and RTsvis showed effects of noise. However, only RTsaud showed an effect of intelligibility. Because of its simplicity in implementation, RTsaud may be a useful effort measure for clinical applications. (C) 2015 Acoustical Society of America

Background: Healthcare providers worldwide are struggling with rising costs while hospitals budgets are under stress. Colorectal cancer surgery is commonly performed, however it is associated with a disproportionate share of adverse events in general surgery. Since adverse events are associated with extra hospital costs it seems important to explicitly discuss the costs of complications and the risk factors for high-costs after colorectal surgery.Methods: Retrospective analysis of clinical and financial outcomes after colorectal cancer surgery in 29 Dutch hospitals (6768 patients). Detailed clinical data was derived from the 2011-2012 population-based Dutch Surgical Colorectal Audit database. Costs were measured uniform in all participating hospitals and based on Time-Driven Activity-Based Costing.Findings: Of total hospital costs in this study, 31 To was spent on complications and the top 5% most expensive patients were accountable for 23% of hospitals budgets. Minor and severe complications were respectively associated with a 26% and 196% increase in costs as compared to patients without complications. Independent from other risk factors, ASA IV, double tumor, ASA III, short course preoperative radiotherapy and TNM-4 stadium disease were the top-5 attributors to high costs.Conclusions: This article shows that complications after colorectal cancer surgery are associated with a substantial increase in costs. Although not all surgical complications can be prevented, reducing complications will result in considerable cost savings. By providing a business case we show that investments made to develop targeted quality improvement programs will pay off eventually. Results based on this study should encourage healthcare providers to endorse quality improvement efforts. (C) 2015 Elsevier Ltd. All rights reserved.

Objectives: Animals with induced tinnitus showed difficulties in detecting silent gaps in sounds, suggesting that the tinnitus percept may be filling the gap. The main purpose of this study was to evaluate the applicability of this approach to detect tinnitus in human patients. The authors first hypothesized that gap detection would be impaired in patients with tinnitus, and second, that gap detection would be more impaired at frequencies close to the tinnitus frequency of the patient. Design: Twenty-two adults with bilateral tinnitus, 20 age-matched and hearing loss–matched subjects without tinnitus, and 10 young normal-hearing subjects participated in the study. To determine the characteristics of the tinnitus, subjects matched an external sound to their perceived tinnitus in pitch and loudness. To determine the minimum detectable gap, the gap threshold, an adaptive psychoacoustic test was performed three times by each subject. In this gap detection test, four different stimuli, with various frequencies and bandwidths, were presented at three intensity levels each. Results: Similar to previous reports of gap detection, increasing sensation level yielded shorter gap thresholds for all stimuli in all groups. Interestingly, the tinnitus group did not display elevated gap thresholds in any of the four stimuli. Moreover, visual inspection of the data revealed no relation between gap detection performance and perceived tinnitus pitch. Conclusions: These findings show that tinnitus in humans has no effect on the ability to detect gaps in auditory stimuli. Thus, the testing procedure in its present form is not suitable for clinical detection of tinnitus in humans., Animal experiments suggest that tinnitus may be related to difficulties in the ability to detect silent gaps in sound. To test this, 22 subjects with hearing loss and bilateral continuous tinnitus, 20 age- and hearing-loss-matched subjects without tinnitus, and ten young normal-hearing controls performed a gap detection test. The authors could not prove evidence for a difference in performance between the subjects with and without tinnitus, leading to the conclusion that the testing procedure in its present form is not suitable for detecting tinnitus in humans.

Temporal envelope cues convey important speech information for cochlear implant (CI) users. Many studies have explored CI users' single-channel temporal envelope processing. However, in clinical Cl speech processors, temporal envelope information is processed by multiple channels. Previous studies have shown that amplitude modulation frequency discrimination (AMFD) thresholds are better when temporal envelopes are delivered to multiple rather than single channels. In clinical fitting, current levels on single channels must often be reduced to accommodate multi-channel loudness summation. As such, it is unclear whether the multi-channel advantage in AMFD observed in previous studies was due to coherent envelope information distributed across the cochlea or to greater loudness associated with multi-channel stimulation. In this study, single- and multi-channel AMFD thresholds were measured in CI users. Multi-channel component electrodes were either widely or narrowly spaced to vary the degree of overlap between neural populations. The reference amplitude modulation (AM) frequency was 100 Hz, and coherent modulation was applied to all channels. In Experiment 1, single- and multi-channel AMFD thresholds were measured at similar loudness. In this case, current levels on component channels were higher for single-than for multi-channel AM stimuli, and the modulation depth was approximately 100% of the perceptual dynamic range (i.e., between threshold and maximum acceptable loudness). Results showed no significant difference in AMFD thresholds between similarly loud single- and multi-channel modulated stimuli. In Experiment 2, single- and multi-channel AMFD thresholds were compared at substantially different loudness. In this case, current levels on component channels were the same for single- and multi-channel stimuli ("summation-adjusted" current levels) and the same range of modulation (in dB) was applied to the component channels for both single- and multi-channel testing. With the summation-adjusted current levels, loudness was lower with single than with multiple channels and the AM depth resulted in substantial stimulation below single-channel audibility, thereby reducing the perceptual range of AM. Results showed that AMFD thresholds were significantly better with multiple channels than with any of the single component channels. There was no significant effect of the distribution of electrodes on multi-channel AMFD thresholds. The results suggest that increased loudness due to multi-channel summation may contribute to the multi-channel advantage in AMFD, and that overall loudness may matter more than the distribution of envelope information in the cochlea. (C) 2015 Elsevier B.V. All rights reserved.

Perception of voice characteristics allows normal hearing listeners to identify the gender of a speaker, and to better segregate speakers from each other in cocktail party situations. This benefit is largely driven by the perception of two vocal characteristics of the speaker: The fundamental frequency (F0) and the vocal-tract length (VTL). Previous studies have suggested that cochlear implant (CI) users have difficulties in perceiving these cues. The aim of the present study was to investigate possible causes for limited sensitivity to VTL differences in CI users. Different acoustic simulations of CI stimulation were implemented to characterize the role of spectral resolution on VTL, both in terms of number of channels and amount of channel interaction. The results indicate that with 12 channels, channel interaction caused by current spread is likely to prevent CI users from perceiving VTL differences typically found between male and female speakers. (C) 2015 Acoustical Society of America.

Despite the great success of using gradient-based controllers to stabilize rigid formations of autonomous agents in the past years, surprising yet intriguing undesirable collective motions have been reported recently when inconsistent measurements are used in the agents' local controllers. To make the existing gradient control robust against such measurement inconsistency, we exploit local estimators following the well known internal model principle for robust output regulation control. The new estimator-based gradient control is still distributed in nature and can be constructed systematically even when the number of agents in a rigid formation grows. We prove rigorously that the proposed control is able to guarantee exponential convergence and then demonstrate through robotic experiments and computer simulations that the reported inconsistency-induced orbits of collective movements are effectively eliminated., 10 pages

In this paper, we study a Passivity-Based Control (PBC) design that solves asymptotic stability with guaranteed safety problem via Interconnection and Damping Assignment (IDA) approach. Akin to the classical IDA-PBC method, the original system is transformed via a state-feedback to a port-Hamiltonian system where the corresponding interconnection and damping matrices and the energy function are shaped according to the given set of unsafe states and to the desired equilibrium point. By embedding it in a hybrid control framework, we show how the global results can also be obtained. We illustrate the efficacy of our proposed method on a nonlinear second-order system.

Purpose Percutaneous needle insertion procedures are commonly used for diagnostic and therapeutic purposes. Although current technology allows accurate localization of lesions, they cannot yet be precisely targeted. Lung cancer is the most common cause of cancer-related death, and early detection reduces the mortality rate. Therefore, suspicious lesions are tested for diagnosis by performing needle biopsy. Methods In this paper, we have presented a novel computed tomography (CT)-compatible needle insertion device (NID). The NID is used to steer a flexible needle (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\phi }0.55\,\hbox {mm}$$\end{document}ϕ0.55mm) with a bevel at the tip in biological tissue. CT images and an electromagnetic (EM) tracking system are used in two separate scenarios to track the needle tip in three-dimensional space during the procedure. Our system uses a control algorithm to steer the needle through a combination of insertion and minimal number of rotations. Results Noise analysis of CT images has demonstrated the compatibility of the device. The results for three experimental cases (case 1: open-loop control, case 2: closed-loop control using EM tracking system and case 3: closed-loop control using CT images) are presented. Each experimental case is performed five times, and average targeting errors are \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$2.86\pm 1.14$$\end{document}2.86±1.14, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.11\pm 0.14$$\end{document}1.11±0.14 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.94\pm 0.63\,\hbox {mm}$$\end{document}1.94±0.63mm for case 1, case 2 and case 3, respectively. Conclusions The achieved results show that our device is CT-compatible and it is able to steer a bevel-tipped needle toward a target. We are able to use intermittent CT images and EM tracking data to control the needle path in a closed-loop manner. These results are promising and suggest that it is possible to accurately target the lesions in real clinical procedures in the future.

Traditionally, modelling using spline curves and surfaces is facilitated by control points. We propose to enhance the modelling process by the use of control vectors. This improves upon existing spline representations by providing such facilities as modelling with local (semi-sharp) creases, vanishing and diagonal features, and hierarchical editing. While our prime interest is in surfaces, most of the ideas are more simply described in the curve context. We demonstrate the advantages provided by control vectors on several curve and surface examples and explore avenues for future research on control vectors in the contexts of geometric modelling and finite element analysis based on splines, and B-splines and subdivision in particular. We extend traditional splines based on control points by incorporating control vectors.Our paradigm allows combining several spline constructions into one formulation.We can model curves and surfaces that are not possible with existing techniques.

Needle-based procedures are commonly performed during minimally invasive surgery for treatment and diagnosis. Accurate needle tip placement is important for the success of the procedures. Misplacement of the needle tip might cause unsuccessful treatment or misdiagnosis. Robot-assisted needle insertion systems have been developed in order to steer flexible bevel-tipped needles. However, current systems depend on the information of maximum needle curvature, which is estimated by performing prior insertions. This work presents a new three-dimensional flexible needle steering system which integrates an optimal steering control, ultrasound-based needle tracking system, needle deflection model, online needle curvature estimation and offline curvature estimation based on biomechanics properties. The online and the offline curvature estimations are used to update the steering control in real time. The system is evaluated by experiments in gelatin phantoms and biological tissues (chicken breast tissues). The average targeting error in gelatin phantoms is 0.42 +/- A 0.17 mm, and in biological tissues is 1.63 +/- A 0.29 mm. The system is able to accurately steer a flexible needle in multi-layer phantoms and biological tissues without performing prior insertions to estimate the maximum needle curvature.

Background. In a Dutch phase II trial conducted between 2006 and 2010, short-course radiotherapy followed by systemic therapy with capecitabine, oxaliplatin, and bevacizumab as neoadjuvant treatment and subsequent radical surgical treatment of primary tumor and metastatic sites was evaluated. In this study, we report the long-term results after a minimum follow-up of 6 years.Methods. Patients with histologically confirmed rectal adenocarcinoma with potentially resectable or ablatable metastases in liver or lungs were eligible. Follow-up data were collected for all patients enrolled in the trial. Overall and recurrence-free survival were calculated using the Kaplan-Meier method.Results. Follow-up data were available for all 50 patients. After a median follow-up time of 8.1 years (range 6.0-9.8), 16 patients (32.0%) were still alive and 14 (28%) were disease-free. The median overall survival was 3.8 years (range 0.5-9.4). From the 36 patients who received radical treatment, two (5.6%) had a local recurrence and 29 (80.6%) had a distant recurrence.Conclusions. Long-term survival can be achieved in patients with primary metastatic rectal cancer after neoadjuvant radio- and chemotherapy. Despite a high number of recurrences, 32% of patients were alive after a median follow-up time of 8.1 years.

This study presents a scaled-bilateral telemanipulation system for magnetic-based control of paramagnetic microparticles. This bilateral control system consists of a haptic device (master-robot) and an electromagnetic system with four orthogonal electromagnetic coils. The electromagnetic system generates magnetic field gradients to control the motion of the microparticle (slave-microrobot). A systematic robust tele-manipulation control design of the microparticles is achieved using disturbance observers (DOBs) to estimate the interaction forces at both the master-robot and slave-microrobot. Experimental results show that point-To-point motion control of the slave-microrobots results in maximum position error of 8 μm in the steady-state. Furthermore, we demonstrate experimentally that interaction forces of tens of micro Newtons, between the slave-microrobot and non-magnetic microbeads, can be estimated using DOBs and scaled-up to the sensory range of the operator.

The use of magnetic resonance (MR) images for needle-based interventions offers several advantages over other types of imaging modalities (e.g., high tissue contrast and no radiation). However, MR-guided interventions face challenges related to electromagnetic compatibility of medical devices and real-time tracking of surgical instruments. This work presents a flexible needle steering system that combines an MR-compatible robot and a Fiber Bragg Grating (FBG)-based needle tip tracker. The MR images are used to localize obstacles and targets, while the FBG sensors provide strain measurements for online estimation of the needle tip position. A pre-operative planner defines the needle entry point and desired path, while a model predictive controller calculates the needle rotation during the insertion. To the best of the authors knowledge, this is the first work that fuses MR images and FBG-based tracking to steer a flexible needle in closed-loop inside the MR bore. The system is validated by steering a bevel-tipped flexible needle towards a physical target in gelatin phantoms and biological tissues. The needle reaches the target in all trials with an average targeting error of 2.76 mm. Disregarding the target displacement during the insertion, the average targeting error drops to 1.74 mm. The preliminary results demonstrate the feasibility of combining MR images and FBG-based needle tip tracking to steer a flexible needle in clinical procedures. In order to move towards to a clinically-relevant application, the design of a flexible Nitinol biopsy needle is also presented and evaluated by experiments in a prostate of a bull. The flexible needle presented a curvature 2.5 times larger than a conventional biopsy needle while maintaining the ability to collect tissue samples.

A numerical time-resolved model is presented for predicting the transition between unidirectional and overloaded motion of catalytic tubular microjets (Ti/Fe/Pt rolled-up microtubes) in an aqueous solution of hydrogen peroxide. Unidirectional movement is achieved by periodic ejection of gas bubbles from one end, whereas formation of multiple bubbles hinders microjet movement in overloaded regime. The influence of nucleation positions of bubbles, hydrogen peroxide concentration, liquid-platinum contact angle, microjet length, and cone angle on the bubble ejection frequency and microjet speed are investigated. We find agreement between the theoretical speeds of the microjet for a range of bubble nucleation positions (0.4L ≤ x0 ≤ 0.6L) and our measurements (108 ± 35 μm/s) for unidirectional motion. In addition, we observe experimentally that transition to overloaded motion occurs for hydrogen peroxide concentration of 5%, whereas our model predicts this transition for concentrations above 2.5%.

WOS: 000405656700002, PubMed ID: 28764445, Top-down repair of interrupted speech can be influenced by bottom-up acoustic cues such as voice pitch (F0). This study aims to investigate the role of the dynamic information of pitch, i.e., F0 contours, in top-down repair of speech. Intelligibility of sentences interrupted with silence or noise was measured in five F0 contour conditions (inverted, flat, original, exaggerated with a factor of 1.5 and 1.75). The main hypothesis was that manipulating F0 contours would impair linking successive segments of interrupted speech and thus negatively affect top-down repair. Intelligibility of interrupted speech was impaired only by misleading dynamic information (inverted F0 contours). The top-down repair of interrupted speech was not affected by any F0 contours manipulation, VIDI from Netherlands Organization for Scientific Research, NWO; Netherlands Organization for Health Research and Development, ZonMw [016.096.397]; University of Groningen; University Medical Center Groningen; Heinsius Houbolt Foundation, The authors would like to thank Floor Burgerhof and Wilke Bosma for transcribing participant responses, as well as the participants. This study was supported by a VIDI grant from the Netherlands Organization for Scientific Research, NWO, and Netherlands Organization for Health Research and Development, ZonMw (Grant No. 016.096.397). Further support came from a Rosalind Franklin Fellowship from the University of Groningen, University Medical Center Groningen, and funds from Heinsius Houbolt Foundation. The study is part of the "Healthy Aging and Communication" research program of the Otorhinolaryngology Department of University Medical Center Groningen and was also conducted in the framework of the LabEx CeLyA ("Centre Lyonnais d'Acoustique," ANR-10-LABX-0060/ANR-11-IDEX-0007) operated by the French National Research Agency.

This paper presents a modular modeling framework for the Ocean Grazer’s Power Take-Off (PTO) system, which operates as an array of point-absorber type devices connected to a hydraulic system. The modeling is based on the port-Hamiltonian (PH) framework that enables energy-based analysis and control of the PTO system. Firstly, a modular model of a point-absorber hydraulic system, which represents the main building block of the PTO, is presented. The model consists of wave-mechanical and hydraulic subsystems that are interconnected with a transformer-type interconnection. Secondly, we show passivity of the point-absorber hydraulic element and the accumulation of potential energy, which is due to the novel pumping mechanism of the point-absorber. Finally, we illustrate these properties through simulation results.