784 research outputs found

    Development of a thin-film porous-microelectrode array (p-mea) for electrical stimulation of engineered cardiac tissue.

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    Electrical stimulation has been increasingly used by research groups to enhance and increase maturation of cells in an engineered cardiac tissue (ECT). Current methods are based on using off-the-shelf wires or electrodes to deliver a stimulus voltage to the in-vitro tissue in culture medium. A major issue with this approach is the generation of byproducts in the medium due to the voltage levels required, which are typically in the range of 5V-10V. No solution currently exists that can accomplish electrical stimulation of cells in an ECT at a low voltage level. Therefore, in this study a novel, porous, thinfilm, microelectrode array (PMEA) device is proposed. The primary advantage of this device is the ability to successfully function at a very low voltage thus minimizing any undesirable oxidative byproducts in the culture environment or cell injury. This was achieved by designing and fabricating a thin device capable of being embedded in the ECT to deliver voltage. The P-MEA device is essentially a thin-film cable i.e. a conducting wire encapsulated with an insulating material; in this case thin-film gold electrodes sandwiched between two layers of insulating polyimide. Major features of the P-MEA include overall dimensions of 10mm width and 82mm length, four arms to allow movement of the individual sensor pads within ECTs, each embedded electrode arm incorporates eight 100μm x 200μm rectangular pores surrounding a 950μm x 340μm exposed electrode, large pads on either side of the porous embedded sensor to function as return electrodes, suture holes to aid in-vivo suturing and stabilization and eight electrode connector pads. Average thickness of the device was 16μm, with an average electrode film thickness of 0.4μm. Electrode resistance ranged from 69.45Ω to 78.52Ω. Electrochemical impedance spectroscopy was performed on the P-MEA electrodes and it confirmed that the P-MEA successfully operates in the 0.01V to 1.0V range with favorable charge transfer characteristics. Proof of principle experiments confirmed the ability of the PMEA to effectively embed within the ECT and electrically stimulate it during chronic, in-vitro culture. Histology imaging shows that the embedding of the device has no adverse effects on the ECT and the cardiomyocytes are aligned within the tissue. Experiments are ongoing to evaluate the role of electrical stimulation on the maturation and function of ECTs which are made of stem cells and other sources. In summary, this device is capable of safe low-voltage electrical stimulation of engineered cardiac tissues (ECTs); it has been designed, fabricated, and its ability to function as a low-voltage stimulus device has been validated using electrochemical tests and in-vitro culture experiments. The design and fabrication of the device went through three major iterations. A final manufacturing process was refined and successfully transferred to the UofL MNTC staff for subsequent manufacturing

    Development of a surrogate bruising detection system to describe potential bruising patterns associated with common childhood falls.

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    Child abuse is a leading cause of fatality in children aged 0-4 years. An estimated 1,700 children die annually as a result of child abuse of which threequarters (75.7%) of the children were younger than 4 years old1. Infants (younger than 1 year) had the highest rate of fatalities among the group. Many of the serious injuries and fatalities could have potentially been prevented if clinicians and child protective services were able to better distinguish between injuries associated with abuse versus those caused by accidents. Missed cases of child abuse have been shown to be as high as 71% of all admitted cases, where children are presented at hospitals for their injuries and not evaluated as being abused 2. Additionally, when child abuse is legally pursued for criminal charges, a little more than half of the cases move forward to prosecution as opposed to being screened out for reasons including the need for further investigation or insufficient evidence 3. Therefore there is a need to provide clinicians, child protective services and law enforcement personnel with improved knowledge related to the types of injuries that are possible from common household accidents that are often reported to be the underlying cause of injury in child abuse. Bruising is an early sign of abuse, and can be an effective indicator of child abuse. Although not life threatening, bruising injuries or bruising patterns provide a “roadmap” documenting a child’s exposure to impact. Previous research has relied upon the use of instrumented anthropomorphic test devices, or test dummies, to investigate injury risk in common childhood falls and accidents in addition to head injury and bone fracture risk in children 4-7. However, the ability to predict bruising patterns occurring in association with falsely reported events in child abuse does not exist, and could prove extremely useful in the distinction between abusive and accidental injuries. This study required the modification of an existing pediatric test dummy to allow for the prediction of potential bruising locations and bruising patterns in children during common household fall events that are often stated as false scenarios in child abuse. The scope of this project included the development of a “sensing skin” that was adapted to a commercial pediatric test dummy. This modified test dummy was then used in mock laboratory experiments replicating common household injury events while the “sensing skin” measured and recorded levels of impact force and locations of impact on the human surrogate. The data from the “sensing skin” was acquired and compiled in a computerized visual body map image displaying the areas of contact or impact locations. This body map image provided a “roadmap” of the human surrogate’s contact exposure during the specific fall event and defined a compatible impact roadmap–specific event combination. Impact roadmap–event combinations for various common household falls provide an indication of where potential bruising could occur. This knowledge of potential bruising patterns could aid clinicians in distinguishing between abusive and accidental injuries for specific fall types

    A modular multi electrode array system for electrogenic cell characterisation and cardiotoxicity applications

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    Multi electrode array (MEA) systems have evolved from custom-made experimental tools, exploited for neural research, into commercially available systems that are used throughout non-invasive electrophysiological study. MEA systems are used in conjunction with cells and tissues from a number of differing organisms (e.g. mice, monkeys, chickens, plants). The development of MEA systems has been incremental over the past 30 years due to constantly changing specific bioscientific requirements in research. As the application of MEA systems continues to diversify contemporary commercial systems are requiring increased levels of sophistication and greater throughput capabilities. [Continues.

    Talking through the body : a comparative study of cognitive-behavioral and attachment based treatments for childhood trauma

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    Childhood abuse and neglect have been shown to have a devastating impact on an individual\u27s social, emotional, and physical development. This study was undertaken in order to determine the best treatment approach for survivors of childhood trauma. The author investigated the impact of traumatic stress on the brain, and reviewed the psychoanalytic, child development, and neurobiological literature on the importance of the attachment relationship for healthy development. Various perspectives on the diagnosis of childhood trauma were explored, including models that centralize childhood trauma as the cause of much of the spectrum of mental illness we see today. The author researched the theoretical underpinnings of both cognitive-behavioral and attachment-based therapies, before analyzing representative interventions from each school of thought in order to determine the strengths and weaknesses of each approach. The author found that each approach has much to offer, but that an attachment-based, neurobiologically-informed perspective is especially relevant when working with survivors of trauma, who may experience dysregulation of the autonomic nervous system, the same system influenced by the attachment relationship. Moreover, because sensory processes stimulate brain areas that mediate the traumatic stress response, interventions that focus on sensory aspects of experience may be more effective for survivors of childhood trauma than cognitive-behavioral techniques alone

    Direct Nerve Stimulation for Induction of Sensation and Treatment of Phantom Limb Pain

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    Design of Improved Surgical Scalpel Handles with Optimized Grips

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    Current designs of scalpel handles are not ideal for hand ergonomics and can lead to difficulties for certain cutting motions or slipping of the tool. A new design was created by Dr. Raymond Dunn at UMass Medical, to improve the shape of the handle as well as adding a rubber material grip portion. The goal of this project is to address the need to limit slipping while taking into consideration comfort and mobility of the instrument. The addition of a texture pattern and choice of material was utilized to increase the friction between the surgical glove and the grip portion of the tool. Testing protocols were created to determine which surface textures provided the highest coefficient of friction, as well as which prototypes were comparable to the precision of the original scalpel design

    Infected Judgment: Legal Responses to Physician Bias

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    Infected Judgment: Legal Responses to Physician Bias

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    Substantial evidence indicates that clinically irrelevant patient characteristics, including race and gender, may at times influence a physician\u27s choice of treatment. Less clear, however, is whether a patient who is the victim of a biased medical decision has any effective legal recourse. Heedful of the difficulties of designing research to establish conclusively the role of physician bias, this article surveys published evidence suggesting the operation of physician bias in clinical decision making. The article then examines potential legal responses to biased medical judgments. A patient who is the subject of a biased decision may sue her doctor for violating his professional duties, including his fiduciary obligation to the patient. Courts may be unwilling, however, to expand the scope of physicians\u27 professional liability beyond existing medical malpractice law. While federal anti-discrimination laws may prohibit some instances of biased medical decisions, those laws leave many instances of physician bias unaddressed. Moreover, those laws typically would require a patient to prove that her doctor acted intentionally in discriminating, a daunting task if the physician\u27s bias is unconscious, as is probably often the case. Finally, under either a professional liability action or a civil rights suit, the patient faces the fundamental problem of proving that bias in fact infected her physician\u27s judgment. Because of these difficulties, the article concludes that existing law does not provide a ready remedy for a patient who is the victim of a biased medical decision
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