bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring in vivo responses to endogenous and exogenous oxidative stress using a novel haem oxygenase 1 reporter mouse
Authors: McMahon Michael , Ding Shaohong , Acosta‐Jimenez Lourdes P. , Frangova Tania G. , Henderson Colin J. , Wolf C. Roland
Published: October 2017

Key points

Haem oxygenase 1 (Hmox1) is a cytoprotective enzyme with anti‐inflammatory and anti‐oxidant properties that is induced in response to multiple noxious environmental stimuli and disease states.

Tools to enable its expression to be monitored in vivo have been unavailable until now.

In a new Hmox1 reporter model we provide high‐fidelity, single‐cell resolution blueprints for Hmox1 expression throughout the body of mice.

We show for the first time that Hmox1 is constitutively expressed at barrier tissues at the interface between the internal and external environments, and that it is highly induced in muscle cells during systemic inflammation.

These data suggest novel biological insights into the role of Hmox1 and pave the way for the use of the model to study the role of environmental stress in disease pathology.

Hmox1 protein holds great promise as a biomarker of in vivo stress responses as it is highly induced in stressed or damaged cells. However, Hmox1 expression patterns have thus far only been available in simple model organisms with limited relevance to humans. We now report a new Hmox1 reporter line that makes it possible to obtain this information in mice, a premiere model system for studying human disease and toxicology. Using a state‐of‐the‐art strategy, we expressed multiple complementary reporter molecules from the murine Hmox1 locus, including firefly luciferase, to allow long‐term, non‐invasive imaging of Hmox1 expression, and β‐galactosidase for high‐resolution mapping of expression patterns post‐mortem. We validated the model by confirming the fidelity of reporter expression, and its responsiveness to oxidative and inflammatory stimuli. In addition to providing blueprints for Hmox1 expression in mice that provide novel biological insights, this work paves the way for the broad application of this model to establish cellular stresses induced by endogenous processes and those resulting from exposure to drugs and environmental agents. It will also enable studies on the role of oxidative stress in the pathogenesis of disease and its prevention.
Monitoring of Parkinson’s Patients Gait Using Simple Walker Based Motion Sensing and Data Analysis
Authors: Aharonson Vered , Schlesinger Ilana , McDonald Andre , Dubowsky Steven , Korczyn Amos
Published: October 2017

Parkinson’s disease (PD) is a degenerative disease with diverse clinical features. At present, there is no definitive test for the diagnosis of PD [1]. Instead, PD is diagnosed using clinical criteria which are based on the presence and presentation of signs such as rest tremor, bradykinesia, rigidity, loss of postural reflexes, shuffling gait and freezing, as well as non-motor symptoms.

Various treatments, ranging from physical therapy and medications to invasive treatments, can help relieve some PD symptoms. These treatments need quantitative monitoring and efficacy evaluation methods in order to provide higher quality, patient-centered care. A quantitative assessment of the patients’ clinical symptoms can also provide a timely alert to adverse events [2]. A variety of devices employing sensors with the purpose of monitoring PD patients’ symptoms were developed [3, 4]. Most of these devices are costly and / or complex in operation and maintenance, which limits their practicality in busy hospital / clinic environments and for home use. Moreover, they do not provide appropriate solutions for monitoring more severe cases of PD, where the patient requires a walking aid such as a cane or walker.
Endoscopic Closure of Large Defect Using Novel Endoscopic Clipping Device and 4S-Modified Roeder Knot
Authors: Ge Shuchen , Ai Liaoyuan , Li Mingyang , Song Chengli
Published: October 2017

Endoscopic closure after endoscopic mucosal resection (EMR), endoscopic submucosal dissection (EMR) or endoscopic full-thickness resection (EFTR) is necessary to eliminate serious complications. Through-the-Scope clips are usually used in treating GI bleeding and perforation for their convenience and reliable outcome, but they are not ideal when the perforation size is larger than 2 cm since their opening width is limited. Several approaches are introduced to reinforce the performance of clips in regarding gathering edges of large defect by using endoloop and clips with double-channel endoscope [1]. Recently, an innovative endoscopic suturing technique using slipknot string and clips with single-channel endoscope has been reported, which resulted in shorter procedure time [2]. However, slipknot cannot maintain for a long time when exposing to distractions due to its poor holding strength.

We have designed and fabricated an endoscopic clipping device and reported its initial ex-vivo results [3]. In this paper, a new suturing method is presented by using this device incorporated with a 4S-Modified Roeder (4SMR) knot, which enables such device to close large defect in a short time. Furthermore, the mechanical strength of 4SMR knot is also studied.
Respiratory Compensation System in Spinal Surgery
Authors: Sun Yu , Chen Haiyun , Jiang Zhongliang , Gao Peng , Hu Ying , Zhang Peng
Published: October 2017

The traditional spinal surgery is often conducted by hand operation with the help of navigation system which is combined with medical image. Although a veteran surgeon has a good adaptability during surgeries, it will tend to decrease along with the increase in surgery time which causes fatigues and leads to low qualities. Many surgical robots have been developed to assist surgeons in operation, and some of them approved by doctors or researchers are DaVinci (Intuitive Surgical, America) [1], Renaissance (Mazor Robotics, Israel), etc. These robot systems have enhanced the accuracy of operation; however, the adaptabilities are still weakened at the same time. During the pedicle screw drilling, surgeons can well adapt to the spine movements mainly caused by respiration, while it is difficult for these robots to adapt to the movements, indicating that the accuracy might drop in the actual application.

Respiratory compensation system is aimed to keep the region of operation stable or reduce the amplitude of fluctuation [2]. The rests of paper introduced the respiratory compensation system and its control algorithm based on infrared tracking data, and experiments were conducted to analyze the accuracy and stability.
A Pan/Tilt Surgical Camera With Parallel Structure and Elastic Platform
Authors: Shen Tao , Nelson Carl , Oleynikov Dmitry
Published: October 2017

Minimally invasive surgery (MIS), including laparoscopy, endoscopy and colonoscopy, refers to performance of diagnostic or surgical intervention in the internal body cavity through small incisions (or no incisions) to reduce the recovery time and minimize scarring [1]. It has gained worldwide popularity since the first report of laparoscopic cholecystectomy in the mid-1980s due to lower complications, cosmetic benefits and quick recovery [2] and has grown to include robotic approaches. One of the main challenges for this type of surgery is to provide sufficient real-time visual feedback using cameras. To address issues of narrow visual field and limited workspace in surgical visual feedback, existing devices may use onboard motors to provide pan and tilt orientation for the camera [3, 4], which makes the system bulky and expensive. (Here we draw a distinction from wire-driven steerable laparoscopes and constrain the discussion to robotic devices.)

In this paper, we present a novel camera system with a parallel structure and elastic platform which has three active degrees of freedom (DOFs) to increase the visual field and implement a mechanical zoom function. This camera head can be mounted on various surgical robots (e.g. [5]) or can be inserted as a standalone device. The novelty of this device lies in its elastic platform, and the authors are unaware of this type of design or its kinematic analysis being presented previously.
Hemodynamics Study of Different Take-Off Angles of the Left Coronary Artery
Authors: Asiruwa John J. , Propst Aaron M. , Gent Stephen P.
Published: October 2017

Coronary arteries are located on the surface of the heart and supply oxygenated blood to the myocardium and other components of the heart. The two coronary arteries located above the aortic arch are the Left Coronary Artery (LCA) and Right Coronary Artery (RCA). The LCA branches into the Left Anterior Descending (LAD) and the Left Circumflex (LCx) while the RCA branches into the Right Marginal Artery (RMA) and Post Descending Artery (PDA). The coronary arteries are likened to a complex tube-like structure, and the motion of the heart cause changes in pressure, which allows proper blood circulation during the systolic and diastolic phases [1].

Since it is essential to understand the physiological and hemodynamical behavior of the heart and coronary arteries, numerous studies have been conducted at different artery locations in the heart. Most of the research has focused on the branches between the LAD and LCx, with little or no attention directed towards the take-off angle the LCA makes with the aortic root. Although it has been reported that certain take-off angles of left main (LM) can be considered anomalous, findings have documented that such take off angles can make the artery prone to atherosclerosis and sudanophilia diseases [2]. Computational Fluid Dynamics (CFD) has in recent years been used to solve a wide variety of fluid flow challenges, and can be used for this study.

The goal of this study is to use CFD techniques to study the hemodynamics of the different take-off angles of the left coronary artery from the aortic root. This will help identify areas in the left coronary artery that could be prone to atherosclerosis buildup.
An Eye Movement Simulator Based on 3-DOF Parallel Mechanism With Flexure Joint
Authors: Liu Jun , Deng Zhen , Sun Yu , Hu Ying
Published: October 2017

In clinical ophthalmic surgery, patient’s eye is not fixed and non-steady state. Surgical operation will be extremely complex and dangerous, which need doctors have a good hand-eye coordination and operating accuracy. Recently, the development of surgical training system promotes the learning speed of clinical experience. Some of them are based on animal specimens. The operating habits and perceptions are similar to the real situation. However, the live animal experiments are more and more challenged by animal ethics. the live animal experiments will be unable to meet the growing demand for training. Others are based on Virtual Reality (VR), which use software to produce realistic images, haptic and other sensations [1]. However, the operating habits and perceptions are quite different from the real situation, and the operating object is stationary. Therefore, it is necessary to develop a device that can simulate the physiological movement of eye to make the result of training can be as close as possible to the actual surgical procedure.

In this paper, an eye movement simulator based on 3-DOF parallel mechanism is presented. The simulator is also equipped with flexure joint, which simulates the biomechanical properties of extraocular muscles. The design and analysis of mechanical will be described.
A Study on the Effects of Struts of Z-Shaped Stent-Grafts on Radial Forces
Authors: Gu Xuelian , Yu Kai , Lu Licheng , Tang Wenjing
Published: October 2017

Endovascular aneurysm repair (EVAR) techniques have been widely used for the treatment of abdominal aortic aneurysm (AAA). EVAR is associated with lower postoperative morbidity and mortality than traditional surgical procedure to treat AAA [1]. However, during the patient’s follow-up, postoperative complications may occur and secondary interventions are required [2].

Stent-grafts fixation in the vessel affects the success of endovascular aneurysm repair. Researches indicate that insufficient stent-graft radial force is attributed to post-surgery complications, such as prosthesis migration and endoleak type I [3, 4]. Endoleak type I happens when there is not a complete contact between stent graft rings and vessel wall. A great radial force can prevent full obturation in the landing zone. The distal endograft fixation also has a great influence on proximal endograft migration after EVAR [5]. Therefore the radial force of the stent plays a significant role.

Single stent-graft ring comprise a series of expandable Z-shaped structural elements (known as “struts”). Currently, there are series of Z-shaped stent-grafts on the market and the struts number ranges from 5 to 12. This work intends to analyze the influence of stent-graft struts number on the radial force. Finite-element analysis (FEA) and experimental method are used.
A Foot-Controlled Interface for Endoscope Holder in Functional Endoscopic Sinus Surgery
Authors: Dai Xinxin , Zhao Baoliang , He Yucheng , Sun Yu , Hu Ying
Published: October 2017

Endoscopic nasal surgery is with minimal invasiveness for the surgical treatment of nasal disease. During traditional functional endoscopic sinus surgery (FESS), the surgeon uses one hand to hold the surgical instrument leaving the other hand to hold the endoscope. When the surgeon needs to use two hands to perform some complex procedure, an assistant surgeon is required to help holding the endoscope, and this requires good teamwork and long-time training. To solve this problem, researchers proposed to use robots to hold the endoscope, freeing the surgeon’s hands for bimanual operation. Sun developed a passive arm with pneumatic locking mechanism to hold the endoscope in FESS, but the surgeon needs to adjust the pose of the endoscope manually, which interrupts the surgery flow and lengthens the surgery time [1]. Many motor-driven endoscope holders have been proposed in literature [2], the surgeon interact with the robot with joystick, voice command, pedals or head movement [3–5]. However, there exists some drawbacks with these interacting methods, for example, joystick requires one of the surgeon’s hands, voice command is usually subject to interference and has long time-delay, foot pedals and head movement distract surgeon’s attention. Lin used a foot-attached IMU sensor to control an active robotic endoscopic holder, the inversion/eversion and abduction/adduction motions of foot are used to select and control different joints, but the motor can be only selected in order, which is unhandy for the four-joint scenario [6].

In this paper, a similar foot-attached IMU sensor is used, and the joints are selected in an easier manner, based on the angle of plantarflexion. Rather than the angle, the angular velocity of abduction/adduction is utilized to control the moving direction of the active joint. This paper describes the test result of the proposed control interface.
The Sensation Meter: An Unprompted Method to Characterize Patient-Reported Bladder Sensation in Real-Time
Authors: Speich John E. , Nagle Anna S. , De Wachter Stefan G. , Klausner Adam P.
Published: October 2017

Overactive bladder (OAB) syndrome is characterized by symptoms of urgency, with or without incontinence, usually with increased voiding frequency and nocturia [1], and is prevalent throughout the world [2]. Chronic OAB symptoms are studied with validated surveys, while acute symptoms can be assessed using bladder diaries. These methods may be subject to recall bias, since diaries are typically completed after voiding. The accepted standard for clinical assessment of bladder function and sensation is a urodynamics (UD) study which involves filling the bladder with a catheter. During a UD study, three verbal sensory thresholds (VSTs) are recorded [3]. These thresholds, First Sensation, First Desire to void, and Strong Desire to void, only provide limited, episodic information about acute sensation during filling. Thus, there is a clear need for a tool to evaluate the development of real-time bladder sensation during bladder filling. The objective of this study was to develop a novel Sensation Meter, a patient interface implemented on a touchscreen device that continuously records the patient’s real-time, unprompted sensation of bladder fullness.
Novel Water Loving Coatings (WLC) Lubricious and Durable Guidewires
Authors: Edwards Peter A. , Price Michael , Nimchuk Nick , Mahon Jeff
Published: October 2017

Hydrophilic coatings applied to guidewires or catheters, lower friction of the device thus improves handling and reduces damage to the vessel walls during access, delivery and retrieval. Peripheral guidewires typically consist of a polymer jacket, basecoat and topcoat. The polymer jacket is highly radiopaque for fluoroscopy visualization. Basecoat adheres to the polymer jacket and hydrophilic topcoat. Basecoat and topcoat play important roles towards coating device durability and lubricity.

Water Loving Coatings (WLC) are the first developed 510(k) clearance guidewires utilizing epoxy polyurethane technology. Coatings are non-hemolytic and non-cytotoxic. WLC are advances toward glycidyl carbamate (GC) resins. Linear Glycidyl Carbamates have shown excellent flexibility based off structure property relationships [1]. Water dispersible GC (WD-GC) oligomers have been prepared by additions of poly(ethylene glycol) methyl ether (m-peg) to isocyanurate and biuret, then end capped with glycidol [2]. WLC technologies are lubricious and durable water dispersible polyurethane or polyurea glycidyl carbamates [3]. Modified Hyaluronate with WD-GC oligomers have shown increases in lubricity of Guidewires when used with a catheter [4]. WLC coatings have been applied to a micro-wire to reduce endothelial mechanical lining damage [5].

Common thermoplastic urethanes (TPU), similar to WLC morphology, used in the medical industry, are: Biomer and Lubrizol’s Pellethane®, Tecoflex™ and Estane™. Biomer consists of 4,4′-Methylenebis(phenyl isocyanate) (MDI), Ethylenediamine (EDA), and Polytetramethylene diol (Poly THF). Pellethane consists of MDI, 1,4-Butanediol (BDO) and Poly THF. Tecoflex consists of 4-4′-methylenebis (cyclohexyl isocyanate) (H12MDI), BDO and Poly THF. Medical grade Estane is an ester of adipic acid with BDO for soft segments and MDI and BDO for hard segments. TPU structure and morphology dictates polymeric properties.
Designing an Extensible Wire Navigation Simulation Platform
Authors: Long Steven , Thomas Geb W. , Anderson Donald D.
Published: October 2017

Orthopaedic resident training has been, and continues to be, in a state of flux. Initially, there were limits placed on the number of hours a resident could work in a week [1]. Later, residency programs were required to provide laboratory-based training in basic surgical skill for first year residents [2]. Now there is a push towards a competency-based training program that graduates residents who demonstrate their acquisition of adequate surgical skills [3]. With each of these shifts in the training model, programs and institutions have looked increasingly to simulation-based training to ease the way. Simulation offers opportunities to train surgeons quickly, provide essential feedback to foster improvement, and assess skill acquisition. With the broad swath of requirements to satisfy in orthopaedic surgical skills training, a simulation platform must support an array of training capabilities for resident practice and performance assessment.

Wire navigation is a central skill in orthopaedics that has a broad variety of applications. In this task, surgeons must use 2D intra-operative fluoroscopic images to visualize the 3D anatomy of a patient and place a wire along a specified path through bone. In some situations, placing the wire is the final task; in others the wire serves as a guide for subsequently placed cannulated implants. Regardless of the situation, the placement of the wire in the bone directly influences the surgical result for the patient.

We previously presented the design of a wire navigation surgical simulator dedicated specifically to hip wire navigation [4]. Our experience with the dozens of surgeons and residents who have used the simulator suggest that they find the general skill of guiding a wire to be relatively abstract. They are more drawn to practicing specific surgeries rather than the general skill. To address this need, we have modified the simulator to present new surgical procedures, while still exercising the underlying skill of wire navigation. We also learned that the task of directing the fluoroscope in order to acquire appropriate view angles for making surgical decisions is integral to surgical wire navigation, so we extended the simulator to include this important aspect of surgical skill.
Development of a Simplified Ankle Distractor
Authors: Baer Thomas , Frisbie Ryan , Willey Michael , Goetz Jessica
Published: October 2017

The physical impairment caused by OA of a single lower extremity joint is comparable to that reported for major life-altering disorders such as end-stage kidney disease and heart failure. (Buckwalter, et al) [1]

Ankle distraction arthroplasty has been shown to greatly decrease pain due to end-stage ankle arthritis. Unlike arthrodesis (fusion of the joint), distraction arthroplasty maintains the joint’s natural movement, and it is far less complicated than total joint replacement surgery. There is a considerable body of research supporting the idea that distraction of an end-stage arthritic joint (most of the work thus far has been done on ankles, although there has also been some investigation of the efficacy of the treatment for knee arthritis) for a period of weeks allows the growth of new tissue in the joint. Although this tissue is not true articular cartilage, distraction arthroplasty has been shown to significantly decrease pain and, in the majority of cases, to be a long lasting remedy for a condition that would otherwise commonly be treated with arthrodesis. [2]

Devices currently available for this procedure are generally quite complicated because they are designed for a wide range of functions related to bone fixation. This versatility also tends to make those systems larger and more expensive, and their aggressively mechanical appearance makes potential joint distraction patients hesitant to select the procedure. While fracture patients may not have a choice about being treated with such devices, elective patients are instinctively resistant to their use, even when assured that the end result will most likely significantly improve in the quality of their lives.
Pop-Up-Inspired Design of a Septal Anchor for a Ventricular Assist Device
Authors: Temel F. Zeynep , McClintock Hayley , Payne Christopher J. , Wamala Isaac , Walsh Conor J. , Vasilyev Nikolay V. , Wood Robert J.
Published: October 2017

Heart failure (HF) is a serious condition in which the heart cannot pump sufficient blood to sustain the metabolic needs of the body. A common indication of failure is a low ejection fraction, or the volumetric proportion of blood ejected when the ventricle contracts. In end-stage HF, support from a ventricular assist device (VAD) can assume some or all of the heart’s pumping work, improving the ejection fraction and restoring normal circulation. VAD therapy options for end-stage right heart failure (RHF) are limited, with only a few FDA-approved devices available for mechanical circulatory support [1]. These devices are based on continuous flow impellers; and despite anticoagulation therapy, use of currently available VADs is associated with thrombogenic risk since the blood must contact artificial non-biologic surfaces.

An implantable VAD for RHF based on soft robotic pulsatile assistance has previously been proposed [2]. This device is comprised of a contractile element that is anchored to the ventricular septum and the right ventricle (RV) free wall. The device is programmed to contract in synchrony with the native heart beat and assist in approximating the septum and free wall together in order to augment blood ejection (Fig. 1). Potential advantages of this approach include reduced risk of thrombosis, since there is no blood flow through the lumen of the device, and the possibility for minimally invasive deployment of the device under ultrasound guidance.

A key component in this VAD concept is the anchoring mechanism that couples the contractile actuator to the ventricular septum. In this work, we report design, fabrication and testing of a new septal anchor design. We exploit the emerging technology of pop-up MEMS [3] in order to fabricate a collapsible anchoring mechanism. Origami-inspired engineering and pop-up MEMS manufacturing techniques have previously been used for developing disposable and low-cost medical tools and devices [4]. The pop-up anchor can be deployed into the left ventricle (LV) via a standard delivery sheath. We validate the load bearing ability of the anchor and demonstrate deployment in an ex vivo simulation.
Human Factors Applications to Mitigate Design Limitations of a Wearable Telemedicine Heart Rate Monitor
Authors: Lowndes Bethany , Finnie Dawn , Hathaway Julie , Ridgeway Jennifer , Vickers-Douglas Kristin , Bruce Charles , Hallbeck Susan
Published: October 2017

The time required to get a device to market is critical to a successful design, development, and manufacturing process [1]. Achieving status of the first device to market is often a priority for manufacturers and developers. Upon market introduction, it is well known that device performance must meet at least minimum standards in order to provide consumer satisfaction and be a successful product to prevent competitive devices from taking over the market [1]. However, if a design only meets minimum expectations, it may struggle to maintain market control. This demonstrates the tradeoffs of speed-to-market and performance, for which optimization has not been clearly defined [2]. Product performance and usability can be designed in, evaluated and enhanced in order to avoid user errors and achieve optimal profitability.

For medical devices, clinical trials are a key step in preparing to take a device to market. Clinical trials can allow for analyses of the effectiveness of the device in the patient care process. For wearable medical devices, patient usability is crucial to patient adherence and safety since the device will be operated by non-medically trained individuals [3,4]. Without adequate usability, adherence and continuity of care are greatly reduced which will reduce the overall effectiveness of the device [5,6]. Human factors principles can best be incorporated in the design process to improve the usability of medical devices and patient safety [5,6,7], specifically for those used in telemedicine [4] and cardiovascular treatment [3]. The objective of this project was to evaluate a telemedicine heart rate monitoring device for patient usability in order to improve the next device’s performance and lead to greater patient adherence for the current version via an improved user manual.
The Effect of a Lower-Limb Sensory Prosthesis on Balance and Gait in People With Peripheral Neuropathy
Authors: Koehler-McNicholas Sara R. , Danzl Lori , Oddsson Lars
Published: October 2017

Peripheral neuropathy (PN), commonly caused by diabetes mellitus, is a debilitating condition that currently affects approximately 20 million Americans. Chronic symptoms of PN often involve pain and weakness of the lower limbs, with eventual sensation loss on the plantar surfaces of the feet. According to epidemiological studies, reduced foot sole sensation has been linked to decreased standing stability [1] and an increased risk of falling [2]. Consequently, cost-effective interventions are needed to improve balance and mobility in this population.

A growing body of research suggests that vibrotactile cues delivered to sensate areas of the lower limb may be an effective way to provide information about foot sole pressure to PN patients who experience poor balance control. Indeed, sensory substitution devices that provide vibrotactile feedback have been shown to aid in balance and improve postural control in various patient populations [3–7]. However, none of these technologies have been based on measurements of foot pressure nor have they been used as a balance prosthesis.

The goal of this study was to investigate the effect of a new external lower-limb sensory prosthesis, the Walkasins™, on the balance and gait of individuals with PN who experience balance problems [8]. Walkasins™ consist of two parts: a leg unit and a foot pad (Figure 1). The leg unit wraps around the lower leg of the user and contains electronics for reading foot pad pressure signals, a microprocessor, and four vibrating motors that provide gentle tactile sensory cues to the front, back, medial, and lateral surfaces of the user’s leg. These cues reflect real-time foot pressure information at a location above the ankle where skin sensation is still present. The leg unit has a power button, two status LEDs, and a reset button (not shown in Figure 1). Power is supplied by a rechargeable internal battery. The foot pad is a thin consumable sole insert that can be cut to size and fit into a regular shoe. The foot pad connects to the leg unit through a physical cable. In this study, subjects performed gait and balance assessments with and without the Walkasins™ turned on in order to determine its short-term effects.
Review of Cardiac Pacemaker Lead Designs for Computational Models in a VR Environment
Authors: Tourek Bethany , Orban Dan , Meng Lingyu , Runesha Hakizumwami Birali , Keefe Dan , Erdman Arthur
Published: October 2017

An implantable cardiac pacemaker is used to modify and treat irregular heartbeats [1] and invented in 1958 [2]. Devices have no fixation or fixed to the heart wall. No fixation leads lay in the bottom of heart cavities, while fixed leads have tines (passive) or a helix screw (active) to attach to the heart. Lead geometries and material properties vary between companies, with geometric sizing based primarily on the internal mechanics of the lead.

Finite element analysis (FEA), computational fluid dynamics (CFD) and bench-top simulations are used to evaluate cardiac leads. These simulations analyze only one lead and struggle to compare and test variations in lead designs. Advanced computational resources can run many computer simulations of anatomical environments, however model complexity increases the time to run each simulation.

To address this issue, we present a simplified parameterized design space for cardiac pacemaker leads in the right atrium. This information will be used to run multiple simulations of leads in blood flow, for visualization in a single virtual reality (VR) environment and allow the designer to iterate through many design variations (See Figure 1).
An Open Source Biometric Patient Identification System for Low Resource Setting
Authors: Noko Ofentse , Lashansky Ariel , Beukes Giancarlo , Sivarasu Sudesh
Published: October 2017

It is estimated that as many as 1.5 billion people globally do not possess any form of identification [1]. Most of these people currently live in Africa and Asia. The lack of identification prevents them from accessing the basic rights and services afforded to them. In healthcare, proof of identity is required to access basic health services, and accurately monitor one’s diagnosis and treatment. This enables health care facilities to provide quality services. Without any identification, governments and development organisations cannot cater to the basic needs of these individuals. This is a key factor in the increased adoption of digital information systems in healthcare. These systems assist with validating patients’ identities. Additionally, these systems store information about patients’ medical history to allow for more effective treatment practices [2]. Digital information systems have proven to be more reliable than paper-based systems currently used in many health facilities in developing countries.

Health service providers are now seeking ways to integrate these systems into their daily operations. Electronic health record systems could potentially solve many problems these facilities face. This includes issues related to data management and patient identification. These systems, when paired with biometric technologies, can remove the need for patients to carry physical identification to gain access to medical services. This would be a great benefit to rural communities. It could also assist with reducing the prevalence of fraud in these communities. Cases where individuals make use of stolen identification cards and multiple identities to access health benefits are known to occur in these areas.

Existing biometric identification solutions are not designed specifically for the rural environment. Therefore, an open source biometric patient identification system was developed. The system was developed specifically for a hospital located in a rural setting. The aim was to leverage off existing technologies, and adapt it accordingly to suit the conditions faced by health service providers in these areas.
The Design and Development of Active Compression Garments for Orthostatic Intolerance
Authors: Duvall Julia , Granberry Rachael , Dunne Lucy E. , Holschuh Brad , Johnson Christopher , Kelly Kevin , Johnson Bruce , Joyner Michael
Published: October 2017

Current compression garments are often made from a spandex-type elastic material with static levels of compression and can become uncomfortable and difficult to don/doff [1]. This limits their usability, especially for unhealthy or aging populations. The only current alternative to elastic compression stockings are inflatable compression sleeves that are controllable, but highly immobile and must be tethered to an inflation source [2]. Neither design offers a solution that is simultaneously low profile, mobile, and controllable. Here we present the design and development of compression garments with embedded shape-changing materials that can produce controllable compression without the need for a bulky inflation system. This active materials approach enables dynamic control over the degree, timing and location of compression, and allows for graded, synchronized, pulsed, and peristaltic compression patterns, which provide the medical benefit of moving fluid in the body [2]. Such a design combines the best features of both elastic and inflatable compression garments: a slim, low-profile form factor that is easy to don/doff and provides dynamic control.

Shape memory alloy (SMA) coil actuators, as described by Holschuh et al., [3] have the ability to apply compressive forces to the body when paired with passive textiles and wrapped circumferentially around the body. These actuators are engineered to contract when heated, creating controllable forces and displacements that are modulated through an applied current. SMA compression garments (SMA-CG) have important applications, from consumer uses to clinical interventions, including: augmenting venous return for conditions of orthostatic intolerance (e.g., postural orthostatic tachycardia syndrome (POTS)); cardiac rehabilitation in heart failure patients; lymphedema venous insufficiency; reducing deep vein thrombosis (DVT) risk; sports performance; and countermeasures for flight or space flight.

While the potential uses for this technology are broad, the basic design is similar across many conditions. Key research areas include: 1) identifying and addressing design considerations relevant to prototype development of SMA-CG; 2) determining the compression thresholds needed to dynamically oppose orthostatic changes; and 3) evaluating the effectiveness of the prototypes for augmented venous return by synchronizing compression during cardiac diastole. Here, we focus on the first question: design of SMA-CG prototypes.
3D Printing in Medicine: Challenges Beyond Technology
Authors: McDaniel Lauralyn
Published: October 2017

Dramatic news headlines imply that the use of additive manufacturing/3D printing in medicine is a brand new way to save and improve lives. The truth is, it’s not so new. Twenty years ago anatomical models were beginning to be used for planning complicated surgeries. In 2000, hearing aid cases were being 3D-printed and within a few years became industry standard. Medical applications have been a leader in taking 3D printing technology far beyond a product development tool. The combination of using medical imaging data to create patient-matched devices and the ability to manufacture structures difficult to produce with traditional technologies is compelling to an industry always looking for ways to innovate.

Surgical uses of 3D printing-centric therapies have a long history beginning with anatomical modeling for bony reconstructive surgery planning[8]. By practicing on a tactile model before surgery surgeons were more prepared and patients received better care. Patient matched implants were a natural extension of this work, leading to truly personalized implants that fit one unique individual[10]. Virtual planning of surgery and guidance using 3D printed, personalized instruments have been applied to many areas of surgery including total joint replacement and craniomaxillofacial reconstruction with great success[9,11]. Further study of the use of models for planning heart and solid organ surgery has lead to increased use in these areas[14]. Finally, hospital-based 3D printing is now of great interest and many institutions are pursuing adding this specialty within individual radiology departments[12,13].

Despite these successful areas of application, widespread use has been fairly slow. Working toward increasing the use of 3D printing in medicine, industry professionals, clinicians, technology developers, and researchers[1] are working together to first identify the challenges and then develop tools and resources to address these challenges.
Medtronic Reveal LINQ™ Devices Provide Better Understanding of Hibernation Physiology in the American Black Bear (Ursus Americanus)
Authors: Iles Tinen L. , Laske Timothy G. , Garshelis David L. , Mattison Lars , Lee Brian , Eisele Val , Gaasedelen Erik , Iaizzo Paul A.
Published: October 2017

The American black bear (Ursus americanus) has been called a metabolic marvel6. In northern Minnesota, where we have conducted long-term physiological and ecological studies of this species, bears may remain in their winter dens for 6 months or more without eating, drinking, urinating or defecating and yet lose very little muscle mass2. We also found that hibernating black bears elicit asystolic events of over 30 seconds and experience an exaggerated respiratory sinus arrhythmia2. In this previous work we employed Medtronic Reveal® XT devices that required us to visit the den and temporarily extract the bear (under anesthesia) to download the stored data.4 Here we describe Medtronic’s latest generation of Insertable Cardiac Monitor (ICM), the Reveal LINQ™, which enables continuous transmission of data via a relay station from the den site3. Black bear hibernation physiology remains of high interest because of the multiple potential applications to human medicine.

ICMs have been used for nearly two decades by clinicians as a critical diagnostic tool to assess the nature of cardiac arrhythmias in humans. Such devices are primarily implanted subcutaneously to record electrocardiograms. The device size, battery life and transmission capabilities have evolved in recent years. The first devices were relatively large and a programmer was needed to retrieve information during each clinical (or in our case, den visit). These devices were programmed to capture cardiac incidents such as asystolic events, arrhythmias and tachycardias and apply algorithms that ensure proper data collection: e.g. ectopy rejection and p-wave presence algorithms.

The new generation Reveal LINQ was made to telemetrically transmit heart data from human patients, but we needed to develop a system to enable transmission from bear dens, which are remote (cannot easily be checked and adjusted) and are subject to extreme winter weather conditions. Besides the advantage of these devices transmitting data automatically, they are considerably smaller and thus less prone to rejection by the extraordinary immune system of the hibernating bear1.
Toward a Low-Cost Modular Powered Transtibial Prosthesis: Initial Prototype Design and Testing
Authors: Wu Molei , Thapa Saroj , Haque Md Rejwanul , Shen Xiangrong
Published: October 2017

In human walking, the ankle plays an important role of supplying power needed for the forward motion [1]. However, traditional transtibial (TT, a.k.a. below-knee, BK) prostheses are passive, lacking the ability of generating power output in the prosthetic ankle. Consequently, amputees fitted with such prostheses suffer from multiple issues (asymmetric gait, greater metabolic energy expenditure, etc.).

To address such issues, researchers have explored various technical approaches to develop powered TT prostheses. Hydraulics and pneumatics have been attempted, leveraging the high power density with these actuators (e.g. [2]). Electromagnetic actuators were used more extensively with its technological maturity and convenience in packaging. Typical examples include the multiple prototypes developed by the MIT Biomechatronics Group (e.g., [3]), the SPARKy project, and the Vanderbilt Transtibial Prosthesis.

The TT prostheses mentioned above all include powered ankle joints to provide power for the users’ locomotion. However, cost and complexity are often given lower priority than performance in the development of such devices. Powered TT prosthesis is a typical low-volume product from a commercial perspective, and the resulting high cost is a major hurdle for the large-scale adoption among amputee users. General robotic components (motors, gearsets, etc.), in contrary, are produced in large quantities with relatively low prices. Such contrast is the major inspiration for this work: the goal is to develop a modular powered TT prosthesis based on low-cost commercial robotic components while minimizing the complexity in manufacturing and assembly.
Sit-to-Stand Control of Powered Knee Prostheses
Authors: Wu Molei , Haque Md Rejwanul , Shen Xiangrong
Published: October 2017

Standing from a seated position is a common, yet dynamically challenging task. Due to the vertical ascent of the body center of gravity, sit-to-stand (STS) transition requires high torque output from the knee. As a result, STS transition poses a major barrier to the mobility of individuals with lower-limb issues, including the transfemoral (TF, also known as above-knee) amputees. A study showed that unilateral TF amputees suffer from high asymmetry in ground reaction forces (53∼69%) and knee moments (110∼124%), while the asymmetry for healthy controls is less than 7% [1]. Note that, although a powered TF prosthesis (Power Knee™) was used in this study, it generated resistance in the STS and thus produced similar results as the passive devices. The inability of existing prostheses in generating knee torque and regulating the torque delivery in the STS seriously affects the mobility of TF amputees in their daily life.

Motivated by this issue, researchers have developed numerous powered TF prostheses (e.g., Vanderbilt powered TF prostheses [2]). These devices are able to generate torque and power for challenging tasks such as STS transition. Making full use of such capability, however, requires an effective controller. Currently, walking control for powered prostheses has been well established, but STS control is much less investigated. Varol et al. developed a multi-mode TF prosthesis controller, in which STS is treated as a transitional motion between sitting and standing states [2]. However, no details were provided on the rationale of the STS controller structure or the determination of the control parameters.

In this paper, a new prosthesis control approach is presented, which regulates the power and torque delivery in the STS process. Inspired by the biomechanical behavior of the knee in the STS motion, the new controller provides two desired functions (gradual loading of the knee at the beginning, and automatic adjustment of the knee torque according to motion progress) with a single equation. Combined with a simple yet reliable triggering condition, the proposed control approach is able to provide natural STS motion for the powered knee prosthesis users.
Low Friction, Long-Stroke Rolling Diaphragm Cylinder for Passive Hydraulic Rehabilitation Robots
Authors: Hashemi Saeed , Durfee William K.
Published: October 2017

Hydraulic actuators are commonly used in mechanical systems, and actuator efficiency is one of the most important factors in these systems [1]. The energy loss to overcome friction force makes the actuator less efficient. Wearable rehabilitation robotics is one of the applications of hydraulic actuators. Hydraulic cylinders deliver the power extracted from the external resources and/or less stroke-affected limbs to the more stroke-affected limbs (Fig. 1).

O-ring seal, rolling diaphragm, and gap seal cylinders are three common technologies that have been used in different hydraulic systems for years. O-ring seal actuators use an O-ring seal between the piston and cylinder. Rolling diaphragm actuators have a diaphragm between the cylinder and piston which rolls back and forth. In gap seal cylinders, there is a gap between the piston and cylinder. Since it is a tradeoff between leakage and friction, leakage between the two chambers in these cylinders is tolerated to reduce friction (Fig. 2). One study examined low friction cylinders in a low pressure hydraulic transmission [2]. In this study, rolling diaphragm cylinders were used in the transmission, but the restriction on stroke length of these cylinders is a problem that needs to be solved. Commercial rolling diaphragms are manufactured using compression molding of a sheet rubber and woven fabric [2], a manufacturing method that limits the stroke length to no more than the bore of the cylinder. Rolling diaphragm cylinders with the higher stroke-to-bore ratios could multiply the work per cycle of the system [2]. Furthermore, there are limitations of using short stroke length rolling diaphragm cylinders [3] [4].

A more thorough friction evaluation of various cylinder technologies is needed to determine which technology has the lowest friction and is most appropriate for low pressure hydraulic systems like rehabilitation robots. Developing a low friction, leakage-free cylinder without stroke limitations is needed for small hydraulics.

Using an experimental test, we measured the resistance forces in three types of cylinders: O-ring, gap seal, and rolling diaphragm. The cylinders were tested at low-pressure and with mineral oil to determine the lowest friction cylinder technology. The same friction test was performed in a novel, long-stroke, rolling diaphragm cylinder (LSRD) to compare it in two different thicknesses with commercial actuators.