215 research outputs found

    Applications of aerospace technology in biology and medicine

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    Utilization of National Aeronautics and Space Administration (NASA) technology in medicine is discussed. The objective is best obtained by stimulation of the introduction of new or improved commercially available medical products incorporating aerospace technology. A bipolar donor/recipient model of medical technology transfer is presented to provide a basis for the team's methodology. That methodology is designed to: (1) identify medical problems and NASA technology that, in combination, constitute opportunities for successful medical products; (2) obtain the early participation of industry in the transfer process; and (3) obtain acceptance by the medical community of new medical products based on NASA technology. Two commercial transfers were completed: the Stowaway, a lightweight wheelchair that provides mobility for the disabled and elderly in the cabin of commercial aircraft, and Micromed, a portable medication infusion pump for the reliable, continuous infusion of medications such as heparin or insulin. The marketing and manufacturing factors critical to the commercialization of the lightweight walker incorporating composite materials were studied. Progress was made in the development and commercialization of each of the 18 currently active projects

    Ventriculovenous shunts are predisposed to thrombotic complications

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    Diagnostic and Therapeutic MEMS (Micro-Electro-Mechanical Systems) Devices for the Identification and Treatment of Human Disease

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    abstract: Early detection and treatment of disease is paramount for improving human health and wellness. Micro-scale devices promote new opportunities for the rapid, cost-effective, and accurate identification of altered biological states indicative of disease early-onset; these devices function at a scale more sensitive to numerous biological processes. The application of Micro-Electro-Mechanical Systems (MEMS) in biomedical settings has recently emerged and flourished over course of the last two decades, requiring a deep understanding of material biocompatibility, biosensing sensitively/selectively, biological constraints for artificial tissue/organ replacement, and the regulations in place to ensure device safety. Capitalizing on the inherent physical differences between cancerous and healthy cells, our ultra-thin silicone membrane enables earlier identification of bladder cancer—with a 70% recurrence rate. Building on this breakthrough, we have devised an array to multiplex this sample-analysis in real-time as well as expanding beyond bladder cancer. The introduction of new materials—with novel properties—to augment current and create innovative medical implants requires the careful analysis of material impact on cellular toxicity, mutagenicity, reactivity, and stability. Finally, the achievement of replacing defective biological systems with implanted artificial equivalents that must function within the same biological constraints, have consistent reliability, and ultimately show the promise of improving human health as demonstrated by our hydrogel check valve. The ongoing proliferation, expanding prevalence, and persistent improvement in MEMS devices through greater sensitivity, specificity, and integration with biological processes will undoubtedly bolster medical science with novel MEMS-based diagnostics and therapeutics.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

    A Soft Robotic Actuator System for in vivo Modeling of Normal Pressure Hydrocephalus

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    OBJECTIVE: The intracranial pressure (ICP) affects the dynamics of cerebrospinal fluid (CSF) and its waveform contains information that is of clinical importance in medical conditions such as hydrocephalus. Active manipulation of the ICP waveform could enable the investigation of pathophysiological processes altering CSF dynamics and driving hydrocephalus. METHODS: A soft robotic actuator system for intracranial pulse pressure amplification was developed to model normal pressure hydrocephalus in vivo. Different end actuators were designed for intraventricular implantation and manufactured by applying cyclic tensile loading on soft rubber tubing. Their mechanical properties were investigated, and the type that achieved the greatest pulse pressure amplification in an in vitro simulator of CSF dynamics was selected for application in vivo. A hydraulic actuation device based on a linear voice coil motor was developed to enable automated and fast operation of the end actuators. The combined system was validated in an acute ovine pilot in vivo study. RESULTS: In vitro results show that variations in the used materials and manufacturing settings altered the end actuator's dynamic properties, such as the pressure-volume characteristics. In the in vivo model, a cardiac-gated actuation volume of 0.125 mL at a heart rate of 62 bpm caused an increase of 205% in mean peak-to-peak amplitude but only an increase of 1.3% in mean ICP. CONCLUSION: The introduced soft robotic actuator system is capable of ICP waveform manipulation. SIGNIFICANCE: Continuous amplification of the intracranial pulse pressure could enable in vivo modeling of normal pressure hydrocephalus and shunt system testing under pathophysiological conditions to improve therapy for hydrocephalus

    Ventriculoperitoneal Shunt Infections in Paediatric Age Group

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    BACKGROUND: CSF shunts significantly improve the quality of life for patients with Hydrocephalus. Infection associated with a CSF shunt are difficult to treat especially in a limited resource country. Data on infection associated with CSF shunts among children are associated with high morbidity and substantial mortality. METHODS: The present study is a prospective analysis of sixty hydrocephalic children who had undergone shunt surgeries due to multifactorial etiology, their risk factors, antibiotic sensitivity pattern and outcome following surgery for a period of fifteen months. RESULTS: Ten patients out of sixty patients were culture positive, and infection rate was 16.6% with infection load increased in age group less than one year (48%). This study has documented 92% risk of infection within 90 days of surgery. Fever (38%), vomiting (17%), increase in head circumference (15%), altered sensorium and seizures (10%), visual disturbances (5%) were indications of rise in intracranial tension in paediatric age group. The statistically significant risk factors are Obstructive Hydrocephalus and Preterm with Intraventricular Haemorrhage where survival rate increased in former and decreased in latter. The most prevalent organisms were Coagulase Negative Staphylococci (50%), Staphylococcus aureus (10%) and Gram Negative Bacteria (40%). Gram Positive Bacteria was 100% sensitive to Vancomycin quantitative E strip method. MBL producing strain of Acinetobacter (10%) in this study was 100% sensitive to Colistin, Tigecycline, Levofloxacin and Netilimycin. CONCLUSION: Low virulent organisms have subclinical course and high index of suspicion with implementation of quantitative documentation of drug susceptibility pattern in routine will prevent the alarming rise of resistance pattern. Operational Theatre surveillance, Infection Control Committee and standardisation of protocol in collaboration with Microbiology department to adhere stringent stewardship must be implemented in routine tertiary care units to prevent infections in these live saving operations in Neurosurgery

    Cerebrospinal Fluid

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    Cerebrospinal fluid is an essential, clear, and colorless liquid essential for maintaining homeostasis of the brain and neuronal functioning. Its secretion in adults ranges from 400 to 600 ml per day and it is renewed about four or five times daily. Cerebrospinal fluid is mainly reabsorbed from arachnoid granulations. Any disruption in this well-regulated system, such as overproduction, decreased absorption, or obstruction, could lead to hydrocephalus. This book contains essential knowledge about cerebrospinal fluid anatomy and physiology, pathologies related to cerebrospinal fluid, and treatment strategies for cerebrospinal fluid disorders

    Barrier dysfunction or drainage reduction: differentiating causes of CSF protein increase

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    BACKGROUND Cerebrospinal fluid (CSF) protein analysis is an important element in the diagnostic chain for various central nervous system (CNS) pathologies. Among multiple existing approaches to interpreting measured protein levels, the Reiber diagram is particularly robust with respect to physiologic inter-individual variability, as it uses multiple subject-specific anchoring values. Beyond reliable identification of abnormal protein levels, the Reiber diagram has the potential to elucidate their pathophysiologic origin. In particular, both reduction of CSF drainage from the cranio-spinal space as well as blood-CNS barrier dysfunction have been suggested ρas possible causes of increased concentration of blood-derived proteins. However, there is disagreement on which of the two is the true cause. METHODS We designed two computational models to investigate the mechanisms governing protein distribution in the spinal CSF. With a one-dimensional model, we evaluated the distribution of albumin and immunoglobulin G (IgG), accounting for protein transport rates across blood-CNS barriers, CSF dynamics (including both dispersion induced by CSF pulsations and advection by mean CSF flow) and CSF drainage. Dispersion coefficients were determined a priori by computing the axisymmetric three-dimensional CSF dynamics and solute transport in a representative segment of the spinal canal. RESULTS Our models reproduce the empirically determined hyperbolic relation between albumin and IgG quotients. They indicate that variation in CSF drainage would yield a linear rather than the expected hyperbolic profile. In contrast, modelled barrier dysfunction reproduces the experimentally observed relation. CONCLUSIONS High levels of albumin identified in the Reiber diagram are more likely to originate from a barrier dysfunction than from a reduction in CSF drainage. Our in silico experiments further support the hypothesis of decreasing spinal CSF drainage in rostro-caudal direction and emphasize the physiological importance of pulsation-driven dispersion for the transport of large molecules in the CSF
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