bluuebunny/crossref_metadata_2025 huggingface dataset:
From Multiple Gaussian Sequences to Functional Data and Beyond: A Stein Estimation Approach
Authors: Koudstaal Mark , Yao Fang
Published: October 2017

We expand the notion of Gaussian sequence models to n experiments and propose a Stein estimation strategy which relies on pooling information across experiments. An oracle inequality is established to assess conditional risks given the underlying effects, based on which we can quantify the size of relative error and obtain a tuning-free recovery strategy that is easy to compute, produces model parsimony and extends to unknown variance. We show that the simultaneous recovery is adaptive to an oracle strategy, which also enjoys a robustness guarantee in a minimax sense. A connection to functional data is established, via Le Cam theory, for fixed and random designs under general regularity settings. We further extend the model projection to general bases with mild conditions on correlation structure and conclude with potential application to other statistical problems. Simulated and real data examples are provided to lend empirical support to the methodology proposed and to illustrate the potential for substantial computational savings.
Testing Mutual Independence in High Dimension via Distance Covariance
Authors: Yao Shun , Zhang Xianyang , Shao Xiaofeng
Published: October 2017

We introduce an L2-type test for testing mutual independence and banded dependence structure for high dimensional data. The test is constructed on the basis of the pairwise distance covariance and it accounts for the non-linear and non-monotone dependences among the data, which cannot be fully captured by the existing tests based on either Pearson correlation or rank correlation. Our test can be conveniently implemented in practice as the limiting null distribution of the test statistic is shown to be standard normal. It exhibits excellent finite sample performance in our simulation studies even when the sample size is small albeit the dimension is high and is shown to identify non-linear dependence in empirical data analysis successfully. On the theory side, asymptotic normality of our test statistic is shown under quite mild moment assumptions and with little restriction on the growth rate of the dimension as a function of sample size. As a demonstration of good power properties for our distance-covariance-based test, we further show that an infeasible version of our test statistic has the rate optimality in the class of Gaussian distributions with equal correlation.
The temporal relations across burnout dimensions in athletes
Authors: Lundkvist E. , Gustafsson H. , Davis P.A. , Holmström S. , Lemyre N. , Ivarsson A.
Published: October 2017

Burnout is a construct that has garnered considerable attention in sport psychology within recent years. Several hypothesized models regarding how the three dimensions (exhaustion, devaluation, and reduced sense of accomplishment) temporally relate to each other have been advanced. One proposal outlined by Maslach and Leiter suggests that exhaustion predicts devaluation which predicts reduced sense of accomplishment. However, there is no consensus among researchers as it has been argued that exhaustion predicts devaluation and reduced accomplishment separately. The aim of this study was to test multiple alternative hypotheses regarding the relationships of the burnout dimensions in athletes. Two samples of Swedish youth elite athletes with differing time spans between measurements were used. Specifically, one sample involved time‐intensive measures collected every week over an eight‐week period, and the other sample included four measurement points across an 18‐month period. Results showed that none of the previously proposed models outlining the temporal relations of burnout dimensions were supported. Statistical analysis of the models including the cross‐lagged predictions of dimensions did not have any statistically significant impact except when exhaustion negatively predicted devaluation between time 1 (month 0) and time 2 (month 6) in the 18‐month sample; this relation faded in the following time points. Further, issues regarding the stability of devaluation and reduced sense of accomplishment emerged as their autocorrelation were very weak in the time‐intensive sample. These findings raise a number of points for further theoretical and practical discussions about the athlete burnout construct.
Three Faces of Populism in Current Switzerland: Comparing the Populist Communication of the Swiss People's Party, the Ticino League, and the Geneva Citizens’ Movement
Authors: Bernhard Laurent
Published: October 2017

This article breaks new ground by comparatively analyzing the populist communication of the three major radical right parties of current Switzerland – the Swiss People's Party (SVP), the Ticino League (Lega), and the Geneva Citizens Movement (MCG). Based on a quantitative analysis of party newspaper articles published from 2009 to 2015, this study finds that 1) the three parties exhibit higher levels of populist communication than mainstream parties, 2) that the populist communication of both the Lega and the MCG does not vary across issue domains, while the SVP significantly relies more on cultural populism than on economic populism, and 3) that the strong oppositional figures (i.e. Christoph Blocher for the SVP, Giuliano Bignasca for the Lega, and Eric Stauffer for the MCG) more frequently play the populist card than the remaining party members.
Hearing Foreigners’ Voices: Unprecedented Communication for Hearing Foreigners’ Voices in Saudi Arabia
Authors: Bakur Alaa
Published: October 2017

After the Arab Spring uprisings, specifically the events in 2012, the Saudi Arabian Ministry of Labor inaugurated a participatory management department to engage with citizens via the introduction of new policies to meet Saudi citizens’ needs. The department adopted two approaches with which to promote citizen participation and hear and respond to the public’s voice. The approaches were social dialogue and the use of digital communication. The objective of this study is to investigate whether the Ministry of Labor allowed foreigners to participate in and engage with other Saudis to meet their interests in terms of employment, education, and other needs to enjoy the life in Saudi Arabia. The theoretical framework adopted for this paper is based on Nico Carpentier’s work. Data for the present study were collected through document analyses, in-depth interviews, and focus group discussions. The paper shows that opportunities for foreigners to engage and make their voices heard were given to specific groups. These groups, who hold various types of power, were included with ordinary Saudi citizens in terms of the level of participation given by the Saudi government. These foreigner groups were listened to because they had the power to persuade the Minister of Labor to include them with other Saudis. Additionally, ignoring these powerful foreigner groups could have lead them to act against the Saudis’ best interests, which was a main consideration of the Saudi government and Ministry of Labor.
Doctor Distrust: Pragmatism, Intersectionality, and the Confluence of Expertise and Interests
Authors: Williams Lawrence H.
Published: October 2017

The idea that only experts can be privy to knowledge about the world has been strongly contested throughout recent history. Using interviews with 39 British seniors tasked to discuss the role of doctors in matters of life and death, I argue that distrust for expert knowledge stems largely from the belief that knowledge is deeply shaped by personal experience. However, such distrust is not absolute as respondents still hold some faith in medical expertise due to their own perceived lack of medical knowledge and experiences with the medical field. As such, I assert that respondents demonstrate ambivalence towards medical expertise due to the confluence of expertise and interests that they find in the role that doctors play in assisting individuals with their health. I connect my findings to the theoretical traditions of American pragmatism and intersectionality to demonstrate how the ambivalence demonstrated by respondents signals their tacit use of a combination of these theories or what I term pragmatic intersectionality.
Student Errors in Fractions and Possible Causes of These Errors
Authors: Aksoy Nuri Can , Yazlik Derya Ozlem
Published: October 2017

In this study, it was aimed to determine the errors and misunderstandings of 5th and 6th grade middle school students in fractions and operations with fractions. For this purpose, the case study model, which is a qualitative research design, was used in the research. In the study, maximum diversity sampling, which is a purposeful sampling method, was used. For this reason, this study was conducted in a state and a private secondary school on a voluntary basis with 105 5th graders and 84 6th graders, with a total of 189 secondary school students from different levels of achievement. In order to determine students' errors and misconceptions about fractions, two tests were prepared by researchers, ten open-ended questions for 5th graders and twelve open-ended questions for 6th graders. Before these tests were formed, the related field was scanned and the existing misunderstandings were determined. Content analysis method was used on the analyzing of the data. The answer papers of the students were coded and students’ solving were examined in three categories as correct, wrong and blank. In addition to this the solving belongs to wrong category was examined in detail and mistakes of the students were coded and the reason of these mistakes were dwelled on. It is seen from the result of the study that students have misunderstanding and mistakes about fractions. It is seen that students are not using the modellings on the operations with fractions because of that most of the mistake and misunderstandings are about operations with fractions.
Attitudes of Junior National Team Athletes towards Opponents: Ideology/Morals
Authors: Görgüt İlyas , Tutkun Erkut
Published: October 2017

Competitions between countries occur in every field, from science to industry. This competition is inevitable in the field of sports, which is the greatest feature of publicity in countries, one of the tools of getting political advantage and the greatest focus of global capital. This competition, which is seen in the fields of sport, sometimes becomes extreme and situations arise which are far from reflecting the nature of sports. Especially the efforts of athletes to represent their countries in the best way sometimes cause them to behave inappropriately to their opponents. Thus, the purpose of this study is to find out whether athletes’ being on the national team has any effects on their moral structure and to find out whether the attitudes they show to their opponent during competition are ideological or moral. Phenomenologic design was used in the study which was prepared with qualitative research method. The sample group of the study consists of 10 athletes in the junior national team who were determined with maximum variation sampling method. Individual interviews of an average of 10-12 minutes were conducted with the athletes within the context of semi-structured interview technique. The participants were informed that the interviews would be voice recorded and their expressions would later be converted into text to avoid data loss; the interviews were recorded after the necessary permissions were taken. Descriptive and content analysis method were used to analyze the expressions converted into text. Analysis results showed that the athletes stated that being on the national team had positive effects on moral structure due to motivating factors such as representing one’s country and being role models and that they were led by their moral structure while competing with their opponents.
Ribeye protein is intrinsically dynamic but is stabilized in the context of the ribbon synapse
Authors: Chen Zongwei , Chou Shih‐Wei , McDermott Brian M.
Published: October 2017

Key points

The synaptic ribbon is an organelle that coordinates rapid and sustained vesicle release to enable hearing and balance.

Ribeye a and b proteins are major constituents of the synaptic ribbon in hair cells.

In this study, we use optically clear transgenic zebrafish to examine the potential dynamics of ribeye proteins in vivo.

We demonstrate that ribeye proteins are inherently dynamic but are stabilized at the ribbons of hair cells in the ear and the lateral line system.

Ribeye protein is a major constituent of the synaptic ribbon, an organelle that coordinates rapid and sustained vesicle release to enable hearing and balance. The ribbon is considered to be a stable structure. However, under certain physiological conditions such as acoustic overexposure that results in temporary noise‐induced hearing loss or perturbations of ion channels, ribbons may change shape or vanish altogether, suggesting greater plasticity than previously appreciated. The dynamic properties of ribeye proteins are unknown. Here we use transgenesis and imaging to explore the behaviours of ribeye proteins within the ribbon and also their intrinsic properties outside the context of the ribbon synapse in a control cell type, the skin cell. By fluorescence recovery after photobleaching (FRAP) on transgenic zebrafish larvae, we test whether ribeye proteins are dynamic in vivo in real time. In the skin, a cell type devoid of synaptic contacts, Ribeye a‐mCherry exchanges with ribbon‐like structures on a time scale of minutes (t1/2 = 3.2 min). In contrast, Ribeye a of the ear and lateral line and Ribeye b of the lateral line each exchange at ribbons of hair cells an order of magnitude slower (t1/2 of 125.6 min, 107.0 min and 95.3 min, respectively) than Ribeye a of the skin. These basal exchange rates suggest that long‐term ribbon presence may require ribeye renewal. Our studies demonstrate that ribeye proteins are inherently dynamic but are stabilized at the ribbons of sensory cells in vivo.
Rapid recovery and altered neurochemical dependence of locomotor central pattern generation following lumbar neonatal spinal cord injury
Authors: Züchner Mark , Kondratskaya Elena , Sylte Camilla B. , Glover Joel C. , Boulland Jean‐Luc
Published: October 2017

Key points

Spinal compression injury targeted to the neonatal upper lumbar spinal cord, the region of highest hindlimb locomotor rhythmogenicity, leads to an initial paralysis of the hindlimbs.

Behavioural recovery is evident within a few days and approaches normal function within about 3 weeks.

Fictive locomotion in the isolated injured spinal cord cannot be elicited by a neurochemical cocktail containing NMDA, dopamine and serotonin 1 day post‐injury, but can 3 days post‐injury as readily as in the uninjured spinal cord.

Low frequency coordinated rhythmic activity can be elicited in the isolated uninjured spinal cord by NMDA + dopamine (without serotonin), but not in the isolated injured spinal cord.

In both the injured and uninjured spinal cord, eliciting bona fide fictive locomotion requires the additional presence of serotonin.

Following incomplete compression injury in the thoracic spinal cord of neonatal mice 1 day after birth (P1), we previously reported that virtually normal hindlimb locomotor function is recovered within about 3 weeks despite substantial permanent thoracic tissue loss. Here, we asked whether similar recovery occurs following lumbar injury that impacts more directly on the locomotor central pattern generator (CPG). As in thoracic injuries, lumbar injuries caused about 90% neuronal loss at the injury site and increased serotonergic innervation below the injury. Motor recovery was slower after lumbar than thoracic injury, but virtually normal function was attained by P25 in both cases. Locomotor CPG status was tested by eliciting fictive locomotion in isolated spinal cords using a widely used neurochemical cocktail (NMDA, dopamine, serotonin). No fictive locomotion could be elicited 1 day post‐injury, but could within 3 days post‐injury as readily as in age‐matched uninjured control spinal cords. Burst patterning and coordination were largely similar in injured and control spinal cords but there were differences. Notably, in both groups there were two main locomotor frequencies, but injured spinal cords exhibited a shift towards the higher frequency. Injury also altered the neurochemical dependence of locomotor CPG output, such that injured spinal cords, unlike control spinal cords, were incapable of generating low frequency rhythmic coordinated activity in the presence of NMDA and dopamine alone. Thus, the neonatal spinal cord also exhibits remarkable functional recovery after lumbar injuries, but the neurochemical sensitivity of locomotor circuitry is modified in the process.
Robust Discrimination of Normal Sinus Rhythm and Atrial Fibrillation on ECG Using a Multiscale Frequency Technique
Authors: Poigai Arunachalam Shivaram , Annoni Elizabeth M. , Kapa Suraj , Mulpuru Siva K. , Friedman Paul A. , Tolkacheva Elena G.
Published: October 2017

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia affecting approximately 3 million Americans, and is a prognostic marker for stroke, heart failure and even death [1]. 12-lead electrocardiogram (ECG) is used to monitor normal sinus rhythm (NSR) and also detect AF. Although the persistent form of AF can be detected relatively easy, detecting paroxysmal AF is often a challenge since requiring continuous monitoring, which becomes expensive and cumbersome to collect lot of ECG data [1]. Several researchers have attempted to develop new methods to discriminate NSR and AF which are based on R-R interval analysis, linear methods, filtering, spectral analysis, statistical approaches such as entropy etc. which faces limitation of successfully detecting AF of all types with high sensitivity and specificity using short time ECG data [1–3]. The major issues with these approaches is that they often distort the ECG by several pre-processing steps with filters, do not provide reliable discrimination using short ECG time series data and many of them lack real-time capability that makes it difficult to trust the data for diagnosis and treatment. Both clinical and scientific communities recognize these difficulties and the necessity to develop novel methods that can enable accurate monitoring and detection of AF [2]. In addition, robust detection and classification algorithms are essential for delivering appropriate therapy for implantable cardioverter defibrillators (ICD) to provide lifesaving timely action.

In this work, the authors propose and demonstrate the application of a multiscale frequency (MSF) approach [4] for accurate detection and discrimination between AF and NSR ECG traces taken from publically available Physionet database. The MSF approach takes into account the contribution from various frequencies in ECG and thus yield valuable information regarding the chaotic nature of AF. Therefore, we demonstrate that MSF can capture the complexity of AF which is associated with higher MSF value compared with NSR thus enabling robust discrimination e AF manifests itself with numerous chaotic frequencies within the body surface ECG,. We validate the feasibility of this technique to discriminate NSR from AF.
Design of an Adjustable Table Mount for Multifunctional NOTES Robot
Authors: Fischer Shannon , Shen Tao , Nelson Carl , Oleynikov Dmitry
Published: October 2017

Natural orifice transluminal endoscopic surgery (NOTES) is a method in which tools are passed through a natural orifice to the surgical site. This removes the need for external incisions, which can allow patients to recover more quickly without any visible abdominal scarring. This surgical method also has several limitations including limited space, complex lumen geography, and difficult visualization [1]. To address these problems, researchers have developed various tools, including endoscope-based robots [2], and insertable bimanual robots [3]. However, some of the aforementioned constraints/limitations remain, and consideration of accessories for use with these tools remains relevant.

Our lab designed a multifunctional NOTES robot, which consists of a snakelike linkage driven by cables that are attached to motors in an external housing to navigate through the lumen geometry; it also includes a bimanual end effector with interchangeable tool tips [4]. This paper introduces the design of an adjustable table mount to address the limitations related to transluminal insertion. It provides four passive degrees of freedom (DOFs) to grossly place the robot, and enables the robot to be fixed on surgical tables with different sizes. Benchtop testing on a surgical table with a patient mannequin demonstrates its functionality.
Skin Self-Screening Camera for Veterans With Spinal Cord Injury
Authors: Olney Christine , Leestma Jennifer , Hansen Andrew , Ferguson John , Murphy Kruse Mary , Goldish Gary
Published: October 2017

Veterans with spinal cord injury (SCI) are at high risk for developing debilitating pressure injuries, particularly to their seated areas (e.g. coccyx, sacral and gluteal) [1]. To prevent development of a pressure injury the Veteran with SCI is encouraged to invoke multiple prevention strategies [2]. One recommended prevention strategy is to conduct twice daily skin self-screenings. Skin self-screening is usually conducted in the bed, prior to arising in the morning and prior to sleep in the evening. The current method to conduct skin self-screening utilizes a mirror at the end of a long handle. The Veteran with SCI examines at-risk areas for changes in their skin integrity such as discoloration, swelling, or changes in skin texture. This method can take up to 20 minutes to complete. In the event there is a change to skin integrity, the pressure injury prevention protocol advises the Veteran with SCI to off-load that particular area for at least 24 hours [3]. Further, he/she is advised to consult with their skin specialist if the area does not resolve to normal color or texture within that next 24 hour period. The consequences of ignoring an early stage pressure injury can be serious e.g. weeks to months of hospitalization attempting to heal the injury, tens to hundreds of thousands of dollars in healthcare costs, possible surgery to close the wound and possibly death [4].

Informal interviews with Veterans with SCI clarified and validated that conducting skin screening with the mirror could be very challenging due to barriers such as: not having a baseline image to compare to; the mirror image not being viewable to the user due to lack of user flexibility or body habitus; the mirror does not easily allow a complete view of all the at-risk areas; the user not being able to discern what he/she is actually viewing possibly due to mirror image distortion and limited visual acuity.

The need for a better skin self-screening device was evidenced by the advanced pressure injuries Veterans presented to their healthcare providers. Finding a pressure injury in the early stages of development and intervening immediately, such as repositioning, can improve the trajectory of the injury [5]. Therefore the project goal was to offer a better tool for and improve the efficacy of skin self-screening for the Veterans with SCI. To overcome the identified barriers, our team of VA clinicians and engineers of the Minneapolis Adaptive Design & Engineering (MADE) program invented such a device at the Minneapolis VA. This paper presents the patient centered iterative process that was used to develop a skin self-screening device and the future directions for this technology.
Finite Element Analysis on Stellite 17mm Tube Valve for Pediatric Ventricular Assist Device
Authors: Scheib Christopher M. , Newswanger Raymond K. , Beese Allison M. , Bowen Timothy , Lewis Gregory S. , Roush Evan P. , Jhun Choon-Sik , Weiss William J. , Rosenberg Gerson
Published: October 2017

A Stellite 25 17mm tube valve based upon the Björk-Shiley Monostrut (BSM) valve design was developed for use in the Penn State Pediatric Ventricular Assist Device (PVAD) pump [1]. The hook of the valve was designed to hold a Delrin occluding disc in place while allowing the disc to tilt open 70 degrees from the closed position. Unlike common design constraints which remain in the elastic region, the hook experiences plastic deformation twice during the assembly process, making the material choice of Stellite 25 imperative.

Stellite 25 is a cobalt-chromium-tungsten-nickel alloy (Co-20Cr-15W-10Ni) belonging to the material family of superalloys which are commonly used for wear-resistant applications exposed to heat, abrasion, and galling [2, 3]. Along with its excellent in vivo corrosion resistance [4], Stellite 25 exhibits high strength and ductility which permit the hook to be plastically deformed during disc installation while remaining below the strain to failure [3, 4]. Together these qualities make Stellite 25 an ideal material choice for the 17mm tube valve application.

Predicting the resultant stresses and strains is critical for determining the safety and structural reliability of the Stellite 25 17mm tube valve for the PVAD after assembly. After performing finite element analysis (FEA), the simulation results were validated by deflection experiments and metallurgical investigations.
Sensor-Less Fully Transperineal Fusion-Guided Prostate Biopsy
Authors: Hunter ChaKaria , Cesante Marco , Xu Sheng , Wood Bradford J. , Seifabadi Reza
Published: October 2017

Prostate cancer is the most common male cancer in the United States with an estimated 181,000 new cases and 26,000 deaths in 2016 [1]. Transrectal ultrasound (TRUS) guided biopsy is the gold standard for definitive diagnosis in which the imaging and needle insertion are both done transrectally. Since ultrasound guidance results in insufficient sensitivity of prostate cancer diagnosis (40–60%), fusion of preoperative MRI with real-time US has been proposed to increase the sensitivity (∼ 90%). Transperineal biopsies have recently gained attention using a brachytherapy grid to biopsy through the perineum rather than the rectum, practically eliminating the possibility of infection.

To enable MR-US fusion, electromagnetic tracking system is commonly used to make a 3D volume out of a stack of 2D US images acquired during an initial sweep of prostate. The EM tracking however is somewhat undesirable as it adds to the cost of the procedure and is prone to inaccuracies. Therefore, in this study, we propose a method that eliminates the need for such external tracking devices and inserts the needle transperineally thus reducing infection risks. Also, the procedure is more comfortable to the patient since the TRUS probe is eliminated. A patient specific grid template is designed based on the MR image of the patient.
Carpal Tunnel Syndrome Soft Relief Device for Typing Applications
Authors: Zhu Mengjia , Adams Wade , Polygerinos Panagiotis
Published: October 2017

Carpal Tunnel Syndrome (CTS) affects roughly 3%–6% of the working population ages 18–64 [1]. This affliction is caused by applying stress on the median nerve that is routed through the carpal tunnel while it is at a positive or negative angle, greater than 15 degrees in either direction, to the human wrist [2]. The median nerve can become inflamed and swollen due to pressure from the palmar carpal ligament causing numbness, stiffness and in some cases severe pain. Tasks like typing can become nearly impossible when the median nerve is inflamed. A number of products on the market and research prototypes have been suggested that try to alleviate CTS strains, however, these designs are generally passive e.g. braces, splints, etc. Instead of actively trying to adjust the wrist angle, the general trend is to prop the wrist up with some sort of rigid ramp, similar to the bottom of a keyboard [3]. The goal of this work is to design a wearable, soft-actuated, robotic sleeve that will dynamically adjust the position of the wrist in real-time to a neutral angle to prevent or release CTS strains.
Nanomagnetic Biosensor for the Detection of Porcine Interferon Gamma
Authors: Wang Wei , Aboubakr Hamada A. , Vang James , Brenk Victor , Goyal Sagar M. , Collins James
Published: October 2017

Due to the anatomical and physiological similarities to humans that include similar heart size, flow rate, skin, liver enzymes and bone healing, porcine models as a powerful investigational platform have been widely used in research areas such as diabetes, obesity and islet transplantation [1]. The advantages of relative low cost, ease in handling and comparatively short period of breeding time may make swine provide a promising solution to the shortage of human donors and difficulty in isolating purified islets from adult human in future. Porcine cytokines play a significant role in innate immunity, apoptosis, angiogenesis, cell growth and differentiation. They are involved in cellular responses, maintenance of homeostasis, and disease states such as inflammatory disease, cardiovascular disease, and cancer. Thus, the technologies to analyze the expression of cytokines are developed rapidly and are still hot topics. The traditional approach for cytokine detection and quantification is the use of an enzyme-linked immunosorbent assay (ELISA). However, its inability to do multiplex test calls for more robust detection system. Biochip-based assay for the detection of biological agents using giant magnetoresistive (GMR) sensors and magnetic nanoparticles have emerged recently [2, 3]. It is proved that the nanomagnetic biosensor technology has advantages of low cost, high sensitivity, multiplexity, and real-time signal readout. The integration of GMR biosensor and use of weak magnetic fields allow to eventually realize point-of-care and portability. In addition, interferon gamma (IFNγ) is one of the most important porcine cytokines, and is associated with a number of autoinflammatory and autoimmune diseases. In this work, IFNγ is selected as a model target for the detection of porcine cytokine using nanomagnetic GMR biosensor.
Treating Epilepsy via Thermal Ablation: Initial Experiments With an MRI-Guided Concentric Tube Robot
Authors: Chen Yue , Poorman Megan E. , Comber David B. , Pitt E. Bryn , Liu Cindy , Godage Isuru S. , Yu Hong , Grissom William A. , Barth Eric J. , Webster Robert J.
Published: October 2017

Epilepsy is a prevalent neurological disorder affecting 65 million people globally [1]. Anti-epileptic medications fail to provide effective seizure control for 30% of patients, placing them at a 7–17% risk of Sudden Unexplained Death in Epilepsy and recurrent seizures. Surgical resection of the seizure focus is a potentially curative treatment for patients with seizures that electrophysiologically correlate to a focal lesion. For these patients, focal surgical resection can result in 60–70% seizure-freedom rates [2]. However, open resection carries the risk of cognitive impairment or focal neurologic deficit [3].

Recent innovations in MRI enable high resolution soft tissue visualization, and real-time temperature monitoring, making MR-guided ablation therapy a promising minimally invasive technique to restrict the tissue destruction to just the seizure focus. Commercial products (e.g., Visualase, Medtronic Inc.; ClearPoint, MRI Interventions Inc.; NeuroBlate, Monteris Inc.) have recently been introduced for MR-guided laser-based thermal ablation. These products require the physician drill a hole into the skull for ablation probe placement, and may not always be able to ablate the entire seizure focus when the structure has a curved shape (such as the hippocampus) [4]. Incomplete ablation of the seizure focus would lead to seizure recurrence.

We have recently proposed concentric-tube steerable needles as a means to address these challenges [4–7]. They enable nonlinear trajectories and offer the potential to enter the brain through the patient’s cheek via a natural opening in the skull base (i.e. the foramen ovale). We have designed and fabricated an MR-compatible robotic system to provide high resolution actuation for helical needle deployment [5]. We have shown in simulation that the curved medial axis of hippocampus can be accessed via a helical needle that delivers the ablation probe into the brain [4]. These preliminary results suggest that MR-guided robotic transforamenal thermal therapy could potentially provide a less invasive approach for potentially curative epilepsy treatment. In this paper we present our first results delivering heat along curved paths in brain phantoms and imaging the resulting treatment zones using MRI.
A New Design of the Miniature Force Sensor Based on Strain Gages for Ablation Catheter
Authors: Shi Xiaochan , Gu Xuelian , Tan Jiahong , Liang Bo
Published: October 2017

Recently, the radiofrequency ablation catheter is widely used in the treatment of atrial fibrillation. Radiofrequency catheter tip is inserted through femoral vein puncture and pushed to the heart cavity. The radio frequency energy is applied to the ablation lesion on the inner wall of the heart, and then the heart cells die to achieve the aim of treatment[1]. During the treatment, however, the patients need repeated ablation because of the ineffective ablation, and the complications may occur. Continuous pulmonary vein lesion and isolation of wall is very important to increase the success of surgery [2]. Research [3] shows that the contact force between catheter tip and the tissue of inner heart is a key factor influencing the lesion size.

In order to monitor the contact force, many force sensors have been studied. Fukuda [4] used semiconductor strain gage outside of the catheter to monitor the contact force. Peirs [5] monitored the contact force by optical technology.

The disadvantages of the current sensors are using special expensive signal detecting and analyzing instrument, such as Endosense (SMART touch), which will increase the cost tremendously. For clinical application, it is necessary to develop a low cost sensor with enough accuracy which can also be used in the catheter for contact force measurement.

This paper focuses on designing a novel force-voltage transferring sensor. The sensor consists of a Ni-Ti alloy tube and several strain gages. With the compact design of a spiral structure, it can reduce the overall cost while keeping a good performance at the same time. The price of SMART touch catheter is 4, 348 dollars. The proposed design will be as much as 20–30 percent below SMART’s price.
Time Variate Comparison of In Situ and In Vitro Monophasic Action Potential Recordings
Authors: Schmidt Megan M. , Iaizzo Paul A.
Published: October 2017

Monophasic action potentials (MAPs) have long been used as a means to study the focal electrical activity of the myocardium. [1, 2] Upon the application of adequate contact force, the signals provide important insights into focal depolarization and repolarization, activation timing, and focal arrhythmic behaviors. [3–6]

Within our laboratory we have developed an isolated physiologic, four-chamber working, large mammalian heart model (the Visible Heart® methodology) to study cardiac devices and their interactions with the myocardium. [7] Through the use of a modified Krebs-Henseleit buffer, we can uniquely visualize the device-tissue interface: in this study, the placement of catheters.

The purpose of this study was two-fold. First, we demonstrated the long term stability of MAP recordings in an in situ swine model. Second, we showed the relationship between MAPs recorded from in vitro and in situ preparations of each specimen.
Development of a Robotic Motor Skills Assessment System for Children With Autism
Authors: Subramani Guru , Fisher Aubrey M. , Bittmann Moria F. , Mason Andrea H. , Travers Brittany G. , Zinn Michael R.
Published: October 2017

Autism is a developmental disorder characterized by atypical social interactions and repetitive behaviors/restricted interests[1]. It is found that children with autism also experience delayed or impaired motor skills development [2]. It would be advantageous to develop methods that precisely evaluate these motor skills impairments. The use of robots for evaluating upper limb motor competency have been looked at in the stroke literature [3]. We would like to leverage robotic tools for motor skills assessment but with focus for children with autism spectrum disorder.

Robotic methodologies provide a unique way of testing upper limb motor skills. For instance, if a person holds on to the end of a robot arm and moves the robot arm in space, the robot can apply forces and prevent or assist the person with these motions. In this fashion, the robot can apply perturbations in a repeatable and precise manner with high fidelity.

Since individuals with autism have anxieties interacting with other individuals[4], using an impersonal robot would alleviate the anxiety of social interactions. These individuals learn motor skills best with consistent repetition and strong reinforcement, qualities that robots provide.

Therefore, a robot based evaluation strategy and therapy paradigm for children with Autism would be beneficial for the community.
A Novel Hyperspectral Endoscopic Imaging Method Based on Broad- and Overlapped-Band Filters
Authors: Han Zhimin , Xie Tianyu , Zhang Aoyu
Published: October 2017

In medical domain, hyperspectral imaging (HSI) [1] offers a hybrid modality of optical diagnostics that obtains spectral information and renders the information in image form, thus it has great potential for noninvasive disease diagnosis and surgical guidance [2]. Masood [3] explored a series of research problems for classification of hyperspectral (HS) colon biopsy images, and concluded that HSI has enough discriminatory power to distinguish normal and malignant biopsy tissues.

However, HS illumination is always with low intensity and signal-to-noise (SNR) ratio is low for HS images. The reason is that sensors of endoscopic systems, such as charged-couple-device (CCD), work by converting photons into electrons which are then stored in each pixel. The number of electrons stored in each pixel well is proportional to the number of photons that struck that pixel, although in actual pixel well, electrons are not only generated when receiving photons, but also due to physical processes within CCD itself, such as thermal noise which generates additional electrons dependent to temperature [4,5]. At the same time, dispersive device such as monochromators (such as prism and grating), and optical filters (including interference filters and tunable filters) are commonly used for HS imaging. Using these traditional filtering approaches, only a low fractions of photons are transmitted into the sensor. Moreover, due to the requirements of safety and keeping the working time per frame as short as possible for in-vivo and real-time application in medical domain, common methods which could improve SNR, such as using cooled sensor or high exposure time, are not applicable for HS endoscopy systems. To overcome this drawback, we proposed this novel HS imaging method based on broad- and overlapped-band filters [6].
Toward Inkjet Additive Manufacturing Directly Onto Human Anatomy
Authors: Johnson Reed A. , O’Neill John J. , Dockter Rodney L. , Kowalewski Timothy M.
Published: October 2017

Bioprinting technology has been rapidly increasing in popularity in the field of tissue engineering. Potential applications include tissue or organ regeneration, creation of biometric multi-layered skin tissue, and burn wound treatment [1].

Recent work has shown that living cells can be successfully applied using inkjet heads without damaging the cells [2]. Electrostatically driven inkjet systems have the benefit of not generating significant heat and therefore do not damage the cell structure. Inkjets have the additional benefit of depositing small droplets with micrometer resolution and therefore can be used to build up tissue like structures.

Previous attempts at tracking and drawing on a hand include either direct contact with the hand [3] or tracking the hand only in two degrees of freedom [4]. In this work we present an approach to track a hand with three degrees of freedom and accurately apply a substance contact free to the hand in a desired pattern using a bioprinting compatible inkjet. The third degree of freedom, in this case depth from the hand surface, provides improved control over the distance between the inkjet head and object, thus increasing deposition accuracy.
A Novel Epidural Catheter Fixation Device
Authors: Cavanagh Daniel P. , Abay Asena , Brito Jessica M. , Joyner Jasmine R. , Nally Jordyn N. , Wu Xianren
Published: October 2017

Epidurals are a method of long-term pain relief administered by injecting and continuously delivering an anesthetic via catheter in the spine. This method of pain relief is often used for patients in the Obstetrics/Gynecology unit as well as those in pre- and post-operational care. For almost 2 million singleton vaginal deliveries across 27 states in 2008 (representing 65% of all US singleton vaginal births in 2008), 61% of patients received some form of an epidural or spinal injection [1]. Additionally, this number has been increasing. For the 18 states for which 2006 and 2008 data are available, the average of the state-level increases in epidural/spinal injections is approximately 4.2% revealing an overall increase in these injections. Just between 2000 and 2010, the use of epidural injections increased by 160% [2]. Commonly, epidural catheters are inserted into the patient’s back in the appropriate location and then secured to the body with an adhesive medical dressing.

Movement and subsequent dislocation of the catheter beneath the adhesive medical dressing can result in inefficient anesthetic delivery, increased patient discomfort, and repeated administration of the epidural. Secondary migration of epidural catheters is a problem responsible for failure in approximately 6.8% of epidurals administered [3]. Requiring an anesthesiologist to repeat the procedure is also an increased cost. A solution to secondary migration of epidural catheters would ensure effective delivery of the anesthetic to the patient, reduce the need for a repeated procedure, and prevent unwanted additional healthcare expenses.
Interpreting Ultrasound Images for Accurate Epidural Needle Insertion
Authors: Vaughan Neil , Dubey Venketesh N.
Published: October 2017

This work presents development and testing of image processing algorithms for the automatic detection of landmarks within ultrasound images.

The aim was to automate ultrasound analysis, for use during the process of epidural needle insertion. For epidural insertion, ultrasound is increasingly used to guide the needle into the epidural space. Ultrasound can improve the safety of epidural and was recommended by the 2008 NICE guidelines (National Institute for Health and Care Excellence). Without using ultrasound, there is no way for the anaesthetist to observe the location of the needle within the ligaments requiring the use of their personal judgment which may lead to injury. If the needle stops short of the epidural space, the anaesthetic is ineffective. If the needle proceeds too deep, it can cause injuries ranging from headache, to permanent nerve damage or death.

Ultrasound of the spine is particularly difficult, because the complex bony structures surrounding the spine limit the ultrasound beam acoustic windows [1]. Additionally, the important structures for epidural that need to be observed are located deeper than other conventional procedures such as peripheral nerve block. This is why a low frequency, curved probe (2–5 MHz) is used, which penetrates deeper but decreases in resolution.

The benefits of automating ultrasound are to enable real-time ultrasound analysis on the live video, mitigate human error, and ensure repeatability by avoiding variation in perception by different users.

Previous ultrasound image processing for epidural research used speckle image enhancement with canny and gradient based methods for bone detection [2]. A clinical trial with 39 patients had success detecting the ligamentum flavum (LF) from ultrasound by algorithms in 87% of patients.

Echogenic needles and catheters are now becoming available which are enhanced for extra ultrasound visibility. The Epimed UltraKath ULTRA-KATH™ [3] has a patented design to maximize visibility under ultrasound [4]. The Echogenic Tuohy Needle also includes imprints on the needle tip that reflects ultrasound, allowing for better visualization. Curved needles can also be detected in 2D ultrasound images [5].
Validation of an Instrumented Wheelchair Hand Rim
Authors: Gaglio Alan , Daigle Scott , Gacek Elizabeth , Jahanian Omid , Slavens Brooke , Rice Ian , Hsiao-Wecksler Elizabeth
Published: October 2017

An estimated 3.26 million manual wheelchair users (MWUs) exist in the United States [1]. MWUs report a high incidence of upper extremity joint pain largely attributed to wheelchair propulsion, which exposes the upper limbs to high forces and torques repetitively over time [2]. There exists a clear need for assistive wheelchair technologies capable of reducing the loads experienced by the upper extremity joints during propulsion.

IntelliWheels, Inc. has developed multi-geared wheel systems, including both low and high gear systems, where a planetary gear train connects the wheel hub to the wheel hand rim. Decreasing gear ratio, we hypothesize, may reduce the forces and torques required by the user during propulsion. To evaluate this claim, we constructed and validated an instrumented wheelchair hand rim system capable of use on either geared or standard wheelchair wheels. Commercially available devices exist to perform wheelchair kinetics, such as the SmartWheel (SW) (Three River Holdings LLC; Mesa, AZ, USA), however, these devices require the use of a manufacturer specified wheel. As a result, a custom solution was required to interface with the geared wheels used in this study.
A Motorized Robotic Walker for Human Walking Assistance
Authors: Afsar Md Rayhan , Wadsworth Michael , Shen Tao , Zhang He , Ye Cang , Shen Xiangrong
Published: October 2017

Impaired mobility is ranked as one of the most important factors that have both physical and mental impacts on patients’ life [1]. The impacts are especially serious for the rapidly expanding elderly population in the United States, which is expected to reach 71 million, approximately 20% of the total population, by 2030 [2]. Existing assistive tools, such as cane and walker/rollator, are helpful for such mobility-challenged individuals by providing additional support in walking. However, such tools also disrupt the users’ walking rhythm and increase their metabolic energy consumption. Wheelchairs, especially powered wheelchairs, are also used extensively among this population. Although wheelchairs are effective in transporting patients, they largely preclude the users’ lower limb muscle activities and bone load-carrying, and accelerate the musculoskeletal degeneration of the user’s lower limb [3].

To address the issues with existing assistive tools, the authors developed a new motorized robotic walker for mobility-challenged users. With the objective of assisting the users’ ambulation in a safe and convenient way, the robotic walker features two independently controlled wheels for the maneuverability of the robot, and two parallel bars for the user support in walking. Unlike similar robotic walkers in prior works (e.g. [4]), no wearable sensors are required for the user. Instead, a 3D computer vision system is used to measure the relative position of the user versus the robot, and the control commands are generated accordingly. The details of the robot design and control are presented in subsequent section.