219 results on '"Vijay K. Varadan"'
Search Results
2. Magnetic nanotubes for drug delivery
- Author
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Prashanth S. Kumar, Mouli Ramasamy, and Vijay K. Varadan
- Subjects
Materials science ,Neurite ,Magnetism ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,Condensed Matter::Materials Science ,Nuclear magnetic resonance ,Dorsal root ganglion ,law ,Microscopy ,medicine ,chemistry.chemical_classification ,Quantitative Biology::Neurons and Cognition ,Biomolecule ,equipment and supplies ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Magnetic field ,medicine.anatomical_structure ,nervous system ,chemistry ,Drug delivery ,Electron microscope ,0210 nano-technology ,human activities - Abstract
Magnetic nanotubes hold the potential for neuroscience applications because of their capability to deliver chemicals or biomolecules and the feasibility of controlling the orientation or movement of these magnetic nanotubes by an external magnetic field thus facilitating directed growth of neurites. Therefore, we sought to investigate the effects of laminin treated magnetic nanotubes and external alternating magnetic fields on the growth of dorsal root ganglion (DRG) neurons in cell culture. Magnetic nanotubes were synthesized by a hydrothermal method and characterized to confirm their hollow structure, the hematite and maghemite phases, and the magnetic properties. DRG neurons were cultured in the presence of magnetic nanotubes under alternating magnetic fields. Electron microscopy showed a close interaction between magnetic nanotubes and the growing neurites Phase contrast microscopy revealed live growing neurons suggesting that the combination of the presence of magnetic nanotubes and the alternating magnetic field were tolerated by DRG neurons. The synergistic effect, from both laminin treated magnetic nanotubes and the applied magnetic fields on survival, growth and electrical activity of the DRG neurons are currently being investigated.
- Published
- 2017
- Full Text
- View/download PDF
3. Atrial fibrillation and sudden cardiac death: catheter-based sensor and mapping system of the heart
- Author
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Prashanth S. Kumar, Vijay K. Varadan, and Mouli Ramasamy
- Subjects
0301 basic medicine ,medicine.medical_specialty ,business.industry ,Atrial fibrillation ,030204 cardiovascular system & hematology ,medicine.disease ,Ventricular tachycardia ,RAPID HEARTBEAT ,Sudden cardiac death ,03 medical and health sciences ,Catheter ,030104 developmental biology ,0302 clinical medicine ,Mapping system ,Heart failure ,Internal medicine ,cardiovascular system ,medicine ,Cardiology ,cardiovascular diseases ,business - Abstract
Ventricular arrhythmias in the heart and the rapid heartbeat of ventricular tachycardia can lead to sudden cardiac death. This is a major health issue worldwide. What is needed is to develop a catheter based sensor and mapping approach which will provide the mechanisms of ventricular arrhythmia, and effectively prevent and treat the same, potentially save life.
- Published
- 2017
- Full Text
- View/download PDF
4. 3D printing of wearable fractal-based sensor systems for neurocardiology and healthcare
- Author
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Mouli Ramasamy and Vijay K. Varadan
- Subjects
Computer science ,business.industry ,3D printing ,Wearable computer ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Neurocardiology ,0104 chemical sciences ,Fractal ,Human–computer interaction ,0210 nano-technology ,business ,Wearable technology - Abstract
Neurocardiology is the pathophysiological interplay of nervous and cardiovascular systems. The communication between the heart and brain has revealed various methodologies in healthcare that could be investigated to study the heart-brain interactions and other cardiovascular and neurological diseases. A textile based wearable nanosensor system in the form of e-bra, e-shirt, e-headband, e-brief, underwear etc, was presented in this SPIE conferences earlier for noninvasive recording of EEG and EKG, and showing the correlation between the brain and heart signals. In this paper, the technology is expanded further using fractal based geometries using 3D printing system for low cost and flexible wearable sensor system for healthcare.
- Published
- 2017
- Full Text
- View/download PDF
5. Left lateral decubitus position on patients with atrial fibrillation and congestive heart failure
- Author
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Mouli Ramasamy, Vijay K. Varadan, and Prashanth S. Kumar
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Supine position ,business.industry ,Left lateral decubitus ,LATERAL DECUBITUS ,Atrial fibrillation ,030204 cardiovascular system & hematology ,medicine.disease ,Comorbidity ,Left lateral decubitus position ,03 medical and health sciences ,0302 clinical medicine ,Clinical evidence ,Heart failure ,Internal medicine ,medicine ,Cardiology ,cardiovascular diseases ,030101 anatomy & morphology ,business ,health care economics and organizations - Abstract
Congestive Heart Failure (CHF) is a cardiovascular disease that affects about 5.7 million people in the US. The most prevalent comorbidity to CHF is Atrial Fibrillation (AF). These two pathologies present in a mutually worsening manner in that patients diagnosed with CHF are more likely to develop AF and patients who are diagnosed with AF are more likely to develop CHF. The underlying pathophysiological mechanisms have been studied for several years and the most recent efforts are in the cellular and molecular basis. In this paper, we focus on manifestation of CHF and AF symptoms as influenced by the posture assumed by a patient. We consider three postures – Left lateral decubitus, right lateral decubitus and supine. We review the clinical evidence gathered thus far relating enhanced sympathetic activity to the left lateral decubitus and supine positions with equivalent evidence on the enhanced vagal activity when the right lateral decubitus posture is assumed. We conclude with a compilation of all the hypotheses on the mechanism by which the right lateral decubitus posture alleviates the symptoms of CHF and AF, and future avenues for investigation.
- Published
- 2017
- Full Text
- View/download PDF
6. Study of heart-brain interactions through EEG, ECG, and emotions
- Author
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Mouli Ramasamy and Vijay K. Varadan
- Subjects
medicine.diagnostic_test ,media_common.quotation_subject ,medicine.medical_treatment ,Cognition ,02 engineering and technology ,Electroencephalography ,021001 nanoscience & nanotechnology ,Biofeedback ,01 natural sciences ,Neurocardiology ,010309 optics ,Perception ,0103 physical sciences ,Happiness ,medicine ,Heart rate variability ,Anxiety ,medicine.symptom ,0210 nano-technology ,Psychology ,media_common ,Cognitive psychology - Abstract
Neurocardiology is the exploration of neurophysiological, neurological and neuroanatomical facets of neuroscience’s influence in cardiology. The paraphernalia of emotions on the heart and brain are premeditated because of the interaction between the central and peripheral nervous system. This is an investigative attempt to study emotion based neurocardiology and the factors that influence this phenomenon. The factors include: interaction between sleep EEG (electroencephalogram) and ECG (electrocardiogram), relationship between emotion and music, psychophysiological coherence between the heart and brain, emotion recognition techniques, and biofeedback mechanisms. Emotions contribute vitally to the mundane life and are quintessential to a numerous biological and everyday-functional modality of a human being. Emotions are best represented through EEG signals, and to a certain extent, can be observed through ECG and body temperature. Confluence of medical and engineering science has enabled the monitoring and discrimination of emotions influenced by happiness, anxiety, distress, excitement and several other factors that influence the thinking patterns and the electrical activity of the brain. Similarly, HRV (Heart Rate Variability) widely investigated for its provision and discerning characteristics towards EEG and the perception in neurocardiology.
- Published
- 2017
- Full Text
- View/download PDF
7. Nanomechanics of carbon nanotubes
- Author
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Prashanth S. Kumar, Vijay K. Varadan, and Mouli Ramasamy
- Subjects
Materials science ,law ,Theoretical models ,Nanotechnology ,Carbon nanotube ,Experimental methods ,Nanomechanics ,law.invention - Abstract
This review focusses on introducing the mechanics in carbon nanotubes (CNT), and the major applications of CNT and its composites in biomedicine. It emphasizes the nanomechanics of these materials by reviewing the widely followed experimental methods, theoretical models, simulations, classification, segregation and applications the aforementioned materials. First, several mechanical properties contributing to the classification of the CNT, for various biomedicine applications, are discussed in detail to provide a cursory glance at the uses of CNT. The mechanics of CNT discussed in this paper include: elasticity, stress, tension, compression, nano-scale mechanics. In addition to these basic properties, a brief introduction about nanoscale composites is given. Second, a brief review on some of the major applications of CNT in biomedicine including drug delivery, therapeutics, diagnostics and regenerative medicine is given.
- Published
- 2017
- Full Text
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8. SAW based micro- and acousto-fluidics in biomedicine
- Author
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Mouli Ramasamy and Vijay K. Varadan
- Subjects
Computer science ,Scale (chemistry) ,Microfluidics ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Range (mathematics) ,Brownian dynamics ,Molecule ,Molecular self-assembly ,Fluidics ,0210 nano-technology ,Macromolecular crowding ,Biological system ,Macromolecule - Abstract
Protein association starts with random collisions of individual proteins. Multiple collisions and rotational diffusion brings the molecules to a state of orientation. Majority of the protein associations are influenced by electrostatic interactions. To introduce: electrostatic rate enhancement, Brownian dynamics and transient complex theory has been traditionally used. Due to the recent advances in interdisciplinary sciences, an array of molecular assembly methods is being studied. Protein nanostructural assembly and macromolecular crowding are derived from the subsets of biochemistry to study protein-protein interactions and protein self-assembly. This paper tries to investigate the issue of enhancing the protein self-association rate, and bridging the gap between the simulations and experimental results. The methods proposed here include: electrostatic rate enhancement, macromolecular crowing, nanostructural protein assembly, microfluidics based approaches and magnetic force based approaches. Despite the suggestions of several methods, microfluidic and magnetic force based approaches seem to serve the need of protein assembly in a wider scale. Congruence of these approaches may also yield better results. Even though, these methods prove to be conceptually strong, to prevent the disagreement of theory and practice, a wide range of experiments is required. This proposal intends to study theoretical and experimental methods to successfully implement the aforementioned assembly strategies, and conclude with an extensive analysis of experimental data to address practical feasibility.
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- 2017
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9. Wearable nanosensor systems and their applications in healthcare
- Author
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Prashanth S. Kumar, Vijay K. Varadan, and Mouli Ramasamy
- Subjects
Activities of daily living ,Computer science ,business.industry ,010401 analytical chemistry ,Wearable computer ,Nanotechnology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,medicine.disease ,01 natural sciences ,0104 chemical sciences ,Chronic disease ,Nanosensor ,Health care ,medicine ,Medical emergency ,0210 nano-technology ,business ,Wearable technology - Abstract
The development of intelligent miniaturized nano-bio-and info-tech based sensors capable of wireless communication will fundamentally change the way we monitor and treat patients with chronic disease and after surgery. These new sensors will allow the monitoring of the patients as they maintain their normal daily activities, and provide warning to healthcare workers when critical events arise. This will facilitate early discharge of patients from hospitals as well as providing reassurance to patients and family that potential problems will be detected at an early stage. The use of continuous monitoring allows both transient and progressive abnormalities to be reliably detected thus avoiding the problems of conventional diagnosis and monitoring methods where by data is captured only for a brief period during hospital/clinic visits. We have been working with a printable organic semiconductor and thin film transistor, and have fabricated and tested various biosensors that can measure important physiological signs before and after surgery. Integrated into "smart" fabrics - garments with wireless technology – and independent e-bandaid sensors, nanosensors in tattoos and socks, minimally invasive implantable devices, the sensor systems will be able to monitor a patient's condition in real time and thus provide point-of-care diagnostics to health-care professionals and greater freedom for patients.
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- 2017
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10. Front Matter: Volume 9802
- Author
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Vijay K. Varadan
- Subjects
Nanosensor ,Nanotechnology - Published
- 2016
- Full Text
- View/download PDF
11. Wireless nanosensor system for diagnosis of sleep disorders
- Author
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Mouli Ramasamy and Vijay K. Varadan
- Subjects
Sleep disorder ,medicine.medical_specialty ,business.industry ,Excessive daytime sleepiness ,02 engineering and technology ,021001 nanoscience & nanotechnology ,medicine.disease ,01 natural sciences ,Sleep in non-human animals ,010309 optics ,Sleep deprivation ,0103 physical sciences ,Medicine ,medicine.symptom ,Headaches ,0210 nano-technology ,business ,Psychiatry ,Body mass index ,Depression (differential diagnoses) ,Asthma - Abstract
A good night's sleep plays a vital role in physical and mental wellbeing by performing the recuperative function for the brain and the body. Notwithstanding the fact that, good sleep is an essential part of a person's life, an increasing number of people are experiencing sleep disorders and loss of sleep. According to the research by the National Institutes of Health (NIH), 50 to 70 million Americans suffer from sleep disorders and sleep deprivation. Although sleep disorder is a highly prevalent condition like diabetes or asthma, 80 to 90 percent of the cases remain undiagnosed. The short-term effects of sleep disorder are morning headaches, excessive daytime sleepiness, shot-term memory loss and depression, but the cumulative long-term effects result in severe health consequences like heart attacks and strokes. In addition, people suffering from sleep disorders are 7.5 times more likely to have a higher body mass index and 2.5 times more likely to have diabetes. Further, undiagnosed and untreated sleep disorders have a significant direct and indirect economic impact. The costs associated with untreated sleep disorders are far higher than the costs for adequate treatment. According to the survey, approximately 16 billion of dollars are spent on medical expenses associated with repeated doctor visits, prescriptions and medications.
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- 2016
- Full Text
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12. Study of emotion-based neurocardiology through wearable systems
- Author
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Mouli Ramasamy and Vijay K. Varadan
- Subjects
050103 clinical psychology ,Modalities ,medicine.diagnostic_test ,medicine.medical_treatment ,media_common.quotation_subject ,05 social sciences ,Electroencephalography ,Biofeedback ,Neurocardiology ,03 medical and health sciences ,0302 clinical medicine ,Perception ,medicine ,Happiness ,Anxiety ,Heart rate variability ,0501 psychology and cognitive sciences ,medicine.symptom ,Psychology ,030217 neurology & neurosurgery ,Cognitive psychology ,media_common - Abstract
Neurocardiology is the exploration of neurophysiological, neurological and neuroanatomical facets of neuroscience’s influence in cardiology. The paraphernalia of emotions on the heart and brain are premeditated because of the interaction between the central and peripheral nervous system. This is an investigative attempt to study emotion based neurocardiology and the factors that influence this phenomena. The factors include: interaction between sleep EEG (electroencephalogram) and ECG (electrocardiogram), relationship between emotion and music, psychophysiological coherence between the heart and brain, emotion recognition techniques, and biofeedback mechanisms. Emotions contribute vitally to the mundane life and are quintessential to a numerous biological and everyday-functional modalities of a human being. Emotions are best represented through EEG signals, and to a certain extent, can be observed through ECG and body temperature. Confluence of medical and engineering science has enabled the monitoring and discrimination of emotions influenced by happiness, anxiety, distress, excitement and several other factors that influence the thinking patterns and the electrical activity of the brain. Similarly, HRV (Heart Rate Variability) widely investigated for its provision and discerning characteristics towards EEG and the perception in neurocardiology.
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- 2016
- Full Text
- View/download PDF
13. Wearable nanosensor system for monitoring mild traumatic brain injuries in football players
- Author
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Mouli Ramasamy and Vijay K. Varadan
- Subjects
medicine.medical_specialty ,Football players ,medicine.diagnostic_test ,business.industry ,Traumatic brain injury ,020209 energy ,Wearable computer ,02 engineering and technology ,Football ,Electroencephalography ,medicine.disease ,Computer security ,computer.software_genre ,Physical medicine and rehabilitation ,Concussion ,0202 electrical engineering, electronic engineering, information engineering ,medicine ,Monitoring methods ,business ,human activities ,computer ,Cumulative effect - Abstract
Football players are more to violent impacts and injuries more than any athlete in any other sport. Concussion or mild traumatic brain injuries were one of the lesser known sports injuries until the last decade. With the advent of modern technologies in medical and engineering disciplines, people are now more aware of concussion detection and prevention. These concussions are often overlooked by football players themselves. The cumulative effect of these mild traumatic brain injuries can cause long-term residual brain dysfunctions. The principle of concussion is based the movement of the brain in the neurocranium and viscerocranium. The brain is encapsulated by the cerebrospinal fluid which acts as a protective layer for the brain. This fluid can protect the brain against minor movements, however, any rapid movements of the brain may mitigate the protective capability of the cerebrospinal fluid. In this paper, we propose a wireless health monitoring helmet that addresses the concerns of the current monitoring methods - it is non-invasive for a football player as helmet is not an additional gear, it is efficient in performance as it is equipped with EEG nanosensors and 3D accelerometer, it does not restrict the movement of the user as it wirelessly communicates to the remote monitoring station, requirement of individual monitoring stations are not required for each player as the ZigBee protocol can couple multiple transmitters with one receiver. A helmet was developed and validated according to the above mentioned parameters.
- Published
- 2016
- Full Text
- View/download PDF
14. Real-time monitoring of drowsiness through wireless nanosensor systems
- Author
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Vijay K. Varadan and Mouli Ramasamy
- Subjects
medicine.diagnostic_test ,Computer science ,business.industry ,020209 energy ,Real-time computing ,Process (computing) ,Wearable computer ,02 engineering and technology ,Electromyography ,Electroencephalography ,Transmission (telecommunications) ,Feature (computer vision) ,Embedded system ,0202 electrical engineering, electronic engineering, information engineering ,medicine ,Wireless ,business ,Electrocardiography - Abstract
Detection of sleepiness and drowsiness in human beings has been a daunting task for both engineering and medical technologies. Accuracy, precision and promptness of detection have always been an issue that has to be dealt by technologists. Generally, the bio potential signals – ECG, EOG, EEG and EMG are used to classify and discriminate sleep from being awake. However, the potential drawbacks may be high false detections, low precision, obtrusiveness, aftermath analysis, etc. To overcome the disadvantages, this paper reviews the design aspects of a wireless and a real time monitoring system to track sleep and detect fatigue. This concept involves the use of EOG and EEG to measure the blink rate and asses the person’s condition. In this user friendly and intuitive approach, EOG and EEG signals are obtained by the textile based nanosensors mounted on the inner side of a flexible headband. The acquired signals are then electrically transmitted to the data processing and transmission unit, which transmits the processed data to the receiver/monitoring module through ZigBee communication. This system is equipped with a software program to process, feature extract, analyze, display and store the information. Thereby, immediate detection of a person falling asleep is made feasible and, tracking the sleep cycle continuously provides an insight about the fatigue level. This approach of using a wireless, real time, dry sensor on a flexible substrate mitigates obtrusiveness that is expected from a wearable system. We have previously presented the results of the aforementioned wearable systems. This paper aims to extend our work conceptually through a review of engineering and medical techniques involved in wearable systems to detect drowsiness.
- Published
- 2016
- Full Text
- View/download PDF
15. Differential diagnosis of cardiovascular diseases and T-wave alternans
- Author
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Mouli Ramasamy and Vijay K. Varadan
- Subjects
medicine.medical_specialty ,Ischemic cardiomyopathy ,business.industry ,Ischemia ,T wave alternans ,030204 cardiovascular system & hematology ,medicine.disease ,Predictive value ,Sudden cardiac death ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Heart failure ,cardiovascular system ,Cardiology ,Medicine ,In patient ,cardiovascular diseases ,030212 general & internal medicine ,Differential diagnosis ,business - Abstract
T wave alternans (TWA) is the variation of the T-wave in electrocardiogram that is observed between periodic beats. TWA is one of the important precursors used to diagnose sudden cardiac death (SCD). Several clinical studies have tried to determine the significance of using TWA analysis to detect abnormalities that may lead to Ventricular Arrhythmias, as well as establish metrics to perform risk stratification for cardiovascular patients with prior cardiac episodes. The statistical significance of TWA in predicting ventricular arrhythmias has been established in patients across several diagnoses. Studies have also shown the significance of the predictive value of TWA analysis in post myocardial infarction patients, risk of SCD, congestive heart failure, ischemic cardiomyopathy, and Chagas disease.
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- 2016
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16. 3D printing of nano- and micro-structures
- Author
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Mouli Ramasamy and Vijay K. Varadan
- Subjects
Organic electronics ,Fabrication ,Textile ,Nanostructure ,business.industry ,Computer science ,Microfluidics ,3D printing ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Signal ,0104 chemical sciences ,0210 nano-technology ,business ,Nanoscopic scale ,Microfabrication - Abstract
Additive manufacturing or 3D printing techniques are being vigorously investigated as a replacement to the traditional and conventional methods in fabrication to bring forth cost and time effective approaches. Introduction of 3D printing has led to printing micro and nanoscale structures including tissues and organelles, bioelectric sensors and devices, artificial bones and transplants, microfluidic devices, batteries and various other biomaterials. Various microfabrication processes have been developed to fabricate micro components and assemblies at lab scale. 3D Fabrication processes that can accommodate the functional and geometrical requirements to realize complicated structures are becoming feasible through advances in additive manufacturing. This advancement could lead to simpler development mechanisms of novel components and devices exhibiting complex features. For instance, development of microstructure electrodes that can penetrate the epidermis of the skin to collect the bio potential signal may prove very effective than the electrodes that measure signal from the skin’s surface. The micro and nanostructures will have to possess extraordinary material and mechanical properties for its dexterity in the applications. A substantial amount of research being pursued on stretchable and flexible devices based on PDMA, textiles, and organic electronics. Despite the numerous advantages these substrates and techniques could solely offer, 3D printing enables a multi-dimensional approach towards finer and complex applications. This review emphasizes the use of 3D printing to fabricate micro and nanostructures for that can be applied for human healthcare.
- Published
- 2016
- Full Text
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17. Wireless nanosensors for monitoring concussion of football players
- Author
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Robert E. Harbaugh, Mouli Ramasamy, and Vijay K. Varadan
- Subjects
medicine.medical_specialty ,Football players ,medicine.diagnostic_test ,business.industry ,Traumatic brain injury ,Brain dysfunction ,Football ,Electroencephalography ,medicine.disease ,Computer security ,computer.software_genre ,Physical medicine and rehabilitation ,Concussion ,medicine ,Wireless ,business ,human activities ,computer ,Cumulative effect - Abstract
Football players are more to violent impacts and injuries more than any athlete in any other sport. Concussion or mild traumatic brain injuries were one of the lesser known sports injuries until the last decade. With the advent of modern technologies in medical and engineering disciplines, people are now more aware of concussion detection and prevention. These concussions are often overlooked by football players themselves. The cumulative effect of these mild traumatic brain injuries can cause long-term residual brain dysfunctions. The principle of concussion is based the movement of the brain in the neurocranium and viscerocranium. The brain is encapsulated by the cerebrospinal fluid which acts as a protective layer for the brain. This fluid can protect the brain against minor movements, however, any rapid movements of the brain may mitigate the protective capability of the cerebrospinal fluid. In this paper, we propose a wireless health monitoring helmet that addresses the concerns of the current monitoring methods - it is non-invasive for a football player as helmet is not an additional gear, it is efficient in performance as it is equipped with EEG nanosensors and 3D accelerometer, it does not restrict the movement of the user as it wirelessly communicates to the remote monitoring station, requirement of individual monitoring stations are not required for each player as the ZigBee protocol can couple multiple transmitters with one receiver. A helmet was developed and validated according to the above mentioned parameters.
- Published
- 2015
- Full Text
- View/download PDF
18. Nanosensor system for monitoring brain activity and drowsiness
- Author
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Mouli Ramasamy, Robert E. Harbaugh, and Vijay K. Varadan
- Subjects
Alertness ,Warning system ,Commercial vehicle ,Computer science ,Detection theory ,Dashboard ,Driving under influence ,Simulation - Abstract
Detection of drowsiness in drivers to avoid on-road collisions and accidents is one of the most important applications that can be implemented to avert loss of life and property caused by accidents. A statistical report indicates that drowsy driving is equally harmful as driving under influence of alcohol. This report also indicates that drowsy driving is the third most influencing factor for accidents and 30% of the commercial vehicle accidents are caused because of drowsy driving. With a motivation to avoid accidents caused by drowsy driving, this paper proposes a technique of correlating EEG and EOG signals to detect drowsiness. Feature extracts of EEG and blink variability from EOG is correlated to detect the sleepiness/drowsiness of a driver. Moreover, to implement a more pragmatic approach towards continuous monitoring, a wireless real time monitoring approach has been incorporated using textile based nanosensors. Thereby, acquired bio potential signals are transmitted through GSM communication module to the receiver continuously. In addition to this, all the incorporated electronics are equipped in a flexible headband which can be worn by the driver. With this flexible headband approach, any intrusiveness that may be experienced by other cumbersome hardware is effectively mitigated. With the continuous transmission of data from the head band, the signals are processed on the receiver side to determine the condition of the driver. Early warning of driver’s drowsiness will be displayed in the dashboard of the vehicle as well as alertness voice and sound alarm will be sent via the vehicle radio.
- Published
- 2015
- Full Text
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19. Neural activity based biofeedback therapy for Autism spectrum disorder through wearable wireless textile EEG monitoring system
- Author
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Ahna Sahi, Vijay K. Varadan, Sechang Oh, Robert E. Harbaugh, Mouli Ramasamy, and Pratyush Rai
- Subjects
medicine.diagnostic_test ,business.industry ,Computer science ,medicine.medical_treatment ,Process (computing) ,Wearable computer ,Electromyography ,Electroencephalography ,medicine.disease ,Biofeedback ,Autism spectrum disorder ,Mu wave ,medicine ,Computer vision ,Artificial intelligence ,Biofeedback therapy ,business ,Simulation ,Mirror neuron - Abstract
Mu waves, also known as mu rhythms, comb or wicket rhythms are synchronized patterns of electrical activity involving large numbers of neurons, in the part of the brain that controls voluntary functions. Controlling, manipulating, or gaining greater awareness of these functions can be done through the process of Biofeedback. Biofeedback is a process that enables an individual to learn how to change voluntary movements for purposes of improving health and performance through the means of instruments such as EEG which rapidly and accurately 'feedback' information to the user. Biofeedback is used for therapeutic purpose for Autism Spectrum Disorder (ASD) by focusing on Mu waves for detecting anomalies in brain wave patterns of mirror neurons. Conventional EEG measurement systems use gel based gold cup electrodes, attached to the scalp with adhesive. It is obtrusive and wires sticking out of the electrodes to signal acquisition system make them impractical for use in sensitive subjects like infants and children with ASD. To remedy this, sensors can be incorporated with skull cap and baseball cap that are commonly used for infants and children. Feasibility of Textile based Sensor system has been investigated here. Textile based multi-electrode EEG, EOG and EMG monitoring system with embedded electronics for data acquisition and wireless transmission has been seamlessly integrated into fabric of these items for continuous detection of Mu waves. Textile electrodes were placed on positions C3, CZ, C4 according to 10-20 international system and their capability to detect Mu waves was tested. The system is ergonomic and can potentially be used for early diagnosis in infants and planning therapy for ASD patients.
- Published
- 2014
- Full Text
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20. Wireless sleep monitoring headband to identify sleep and track fatigue
- Author
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Sechang Oh, Mouli Ramasamy, and Vijay K. Varadan
- Subjects
medicine.diagnostic_test ,Computer science ,business.industry ,Real-time computing ,Process (computing) ,Electroencephalography ,Transmission (telecommunications) ,GSM ,Feature (computer vision) ,medicine ,Wireless ,Sleep (system call) ,business ,Simulation - Abstract
Detection of sleepiness and drowsiness in human beings has been a daunting task for both engineering and medical technologies. Accuracy, precision and promptness of detection have always been an issue that has to be dealt by technologists. Commonly, the rudimentary bio potential signals – ECG, EOG, EEG and EMG are used to classify and discriminate sleep from being awake. However, the potential drawbacks may be high false detections, low precision, obtrusiveness, aftermath analysis, etc. To overcome the disadvantages, this paper proposes the design of a wireless and a real time monitoring system to track sleep and detect fatigue. This concept involves the use of EOG and EEG to measure the blink rate and asses the person’s condition. In this user friendly and intuitive approach, EOG and EEG signals are obtained by the dry gold wire nano-sensors fabricated on the inner side of a flexible headband. The acquired signals are then electrically transmitted to the data processing and transmission unit, which transmits the processed data to the receiver/monitoring module through WCDMA/GSM communication. This module is equipped with a software program to process, feature extract, analyze, display and store the information. Thereby, immediate detection of a person falling asleep is made feasible and, tracking the sleep cycle continuously provides an insight about the experienced fatigue level. The novel approach of using a wireless, real time, dry sensor on a flexible substrate reduces the obtrusiveness, and techniques adopted in the electronics and software facilitates and substantial increase in efficiency, accuracy and precision.
- Published
- 2014
- Full Text
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21. Efficient RF energy harvesting by using a fractal structured rectenna system
- Author
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Vijay K. Varadan, Mouli Ramasamy, and Sechang Oh
- Subjects
Computer science ,business.industry ,RF power amplifier ,Impedance matching ,Resonance ,Fractal antenna ,Rectenna ,Hardware_GENERAL ,Electronic engineering ,Radio frequency ,Antenna (radio) ,Telecommunications ,business ,Energy harvesting - Abstract
A rectenna system delivers, collects, and converts RF energy into direct current to power the electronic devices or recharge batteries. It consists of an antenna for receiving RF power, an input filter for processing energy and impedance matching, a rectifier, an output filter, and a load resistor. However, the conventional rectenna systems have drawback in terms of power generation, as the single resonant frequency of an antenna can generate only low power compared to multiple resonant frequencies. A multi band rectenna system is an optimal solution to generate more power. This paper proposes the design of a novel rectenna system, which involves developing a multi band rectenna with a fractal structured antenna to facilitate an increase in energy harvesting from various sources like Wi-Fi, TV signals, mobile networks and other ambient sources, eliminating the limitation of a single band technique. The usage of fractal antennas effects certain prominent advantages in terms of size and multiple resonances. Even though, a fractal antenna incorporates multiple resonances, controlling the resonant frequencies is an important aspect to generate power from the various desired RF sources. Hence, this paper also describes the design parameters of the fractal antenna and the methods to control the multi band frequency.
- Published
- 2014
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22. Yttrium oxide based three dimensional metamaterials for visible light cloaking
- Author
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Christina Brantley, Eugene Edwards, Vijay K. Varadan, Prashanth S. Kumar, Pratyush Rai, and Paul B. Ruffin
- Subjects
Metamaterial cloaking ,Superlens ,Materials science ,business.industry ,Physics::Optics ,Metamaterial ,X-ray optics ,Theories of cloaking ,Cloaking device ,Electromagnetic radiation ,Surface plasmon polariton ,Optics ,Optoelectronics ,business - Abstract
Metamaterial with negative refractive index is the key phenomenon behind the concept of a cloaking device to hide an object from light in visible spectrum. Metamaterials made of two and three dimensional lattices of periodically placed electromagnetic resonant cells can achieve absorption and propagation of incident electromagnetic radiation as confined electromagnetic fields confined to a waveguide as surface plasmon polaritons, which can be used for shielding an object from in-tune electromagnetic radiation. The periodicity and dimensions of resonant cavity determine the frequency, which are very small as compared to the wavelength of incident light. Till now the phenomena have been demonstrated only for lights in near infrared spectrum. Recent advancements in fabrication techniques have made it possible to fabricate array of three dimensional nanostructures with cross-sections as small as 25 nm that are required for negative refractive index for wavelengths in visible light spectrum of 400-700 nm and for wider view angle. Two types of metamaterial designs, three dimensional concentric split ring and fishnet, are considered. Three dimensional structures consisted of metal-dielectric-metal stacks. The metal is silver and dielectric is yttrium oxide, other than conventional materials such as FR4 and Duroid. High κ dielectric and high refractive index as well as large crystal symmetry of Yttrium oxide has been investigated as encapsulating medium. Dependence of refractive index on wavelength and bandwidth of negative refractive index region are analyzed for application towards cloaking from light in visible spectrum.
- Published
- 2014
- Full Text
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23. Efficient heart beat detection using embedded system electronics
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Mouli Ramasamy, Sechang Oh, and Vijay K. Varadan
- Subjects
medicine.diagnostic_test ,business.industry ,Computer science ,Controller (computing) ,Signal ,Field (computer science) ,Front and back ends ,Microcontroller ,Embedded system ,Computer data storage ,medicine ,Electronics ,business ,Electrocardiography ,Wearable technology - Abstract
The present day bio-technical field concentrates on developing various types of innovative ambulatory and wearable devices to monitor several bio-physical, physio-pathological, bio-electrical and bio-potential factors to assess a human body’s health condition without intruding quotidian activities. One of the most important aspects of this evolving technology is monitoring heart beat rate and electrocardiogram (ECG) from which many other subsidiary results can be derived. Conventionally, the devices and systems consumes a lot of power since the acquired signals are always processed on the receiver end. Because of this back end processing, the unprocessed raw data is transmitted resulting in usage of more power, memory and processing time. This paper proposes an innovative technique where the acquired signals are processed by a microcontroller in the front end of the module and just the processed signal is then transmitted wirelessly to the display unit. Therefore, power consumption is considerably reduced and clearer data analysis is performed within the module. This also avoids the need for the user to be educated about usage of the device and signal/system analysis, since only the number of heart beats will displayed at the user end. Additionally, the proposed concept also eradicates the other disadvantages like obtrusiveness, high power consumption and size. To demonstrate the above said factors, a commercial controller board was used to extend the monitoring method by using the saved ECG data from a computer.
- Published
- 2014
- Full Text
- View/download PDF
24. Front Matter: Volume 8691
- Author
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Vijay K. Varadan
- Subjects
Volume (thermodynamics) ,Mechanics ,Geology ,Front (military) - Published
- 2013
- Full Text
- View/download PDF
25. Study of the electrochemical properties of magnetite, maghemite and hematite nanoparticles for their applications in lithium ion batteries
- Author
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Linfeng Chen, Gaojun Wang, Jining Xie, Vijay K. Varadan, Pratyush Rai, Jungmin Lee, and Gyanesh N. Mathur
- Subjects
Materials science ,Iron oxide ,Maghemite ,Nanoparticle ,chemistry.chemical_element ,engineering.material ,Hematite ,Lithium-ion battery ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,visual_art ,engineering ,visual_art.visual_art_medium ,Lithium ,Iron oxide nanoparticles ,Magnetite - Abstract
Iron oxide nanoparticles, including magnetite, maghemite and hematite, are promising electrode active materials for lithium ion batteries due to their low cost, high capacity and environmental friendliness. Though the electrochemical properties of each kind of iron oxide nanoparticles have been intensively studied, systematic comparison of the three kinds of iron oxides is hardly reported. This paper reports the study and comparison of the electrochemical properties of magnetite, maghemite and hematite nanoparticles with the same shape and size. In this work, hematite and maghemite nanoparticles were obtained from commercial magnetite nanoparticles by thermal treatments at different conditions. Their crystalline structures were characterized by X-ray diffraction (XRD), their magnetic properties were measured by a vibration sample magnetometer (VSM), and their particle morphologies were analyzed by scanning electron microscopy (SEM). Composite electrodes were made from iron oxide nanoparticles with carbon black as the conducting material and PVDF as the binding material (iron oxide : carbon black : PVDF = 70 : 15 : 15). Prototype lithium ion batteries (CR2032 button cells) were assembled with iron oxide composite electrodes as cathodes, metal lithium as anodes, and Celgard 2400 porous membrane as separators. The impedance and discharge-charge behaviors were characterized by a Solartron electrochemical workstation and an Arbin battery tester, respectively. It was found that at the same shape and size, hematite nanoparticles has higher specific discharge and charge capacities than magnetite and maghemite nanoparticles.
- Published
- 2013
- Full Text
- View/download PDF
26. Synthesis and electrochemical properties of spinel lithium manganese oxides for lithium ion batteries
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Gaojun Wang, Vijay K. Varadan, Gyanesh N. Mathur, and Linfeng Chen
- Subjects
Materials science ,Lithium vanadium phosphate battery ,Spinel ,chemistry.chemical_element ,Manganese ,engineering.material ,Electrochemistry ,Lithium-ion battery ,Cathode ,law.invention ,Chemical engineering ,chemistry ,law ,engineering ,Lithium ,Sol-gel - Abstract
Spinel lithium manganese oxides (LiMn 2 O 4 ) are favorable cathode materials for secondary lithium ion batteries mainly due to their low cost and excellent environmental suitability. Further, because of their high electrochemical potentials, spinel lithium manganese oxides are a type of promising cathode materials for high-power lithium ion batteries, such as the batteries for electric vehicles. However, the electrochemical properties of LiMn 2 O 4 are strongly influenced by the synthesis methods and conditions. In this paper, the electrochemical properties of spinel LiMn 2 O 4 synthesized by solid state reaction and sol-gel method were compared and analyzed. The effects of particle sizes on the electrochemical properties of spinel LiMn 2 O 4 were discussed.
- Published
- 2013
- Full Text
- View/download PDF
27. Development of thermoelectric inks for the fabrication of printable thermoelectric generators used in mobile wearable health monitoring systems
- Author
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Sang H. Choi, Jungmin Lee, Linfeng Chen, Hyunjung Kim, Vijay K. Varadan, and Gyanesh N. Mathur
- Subjects
Fabrication ,Materials science ,Thermoelectric generator ,Seebeck coefficient ,Thermoelectric effect ,Wearable computer ,Figure of merit ,Nanotechnology ,Thermoelectric materials ,Energy harvesting ,Engineering physics - Abstract
Power consumption appears to be the biggest technical issue and performance bottleneck in the development of mobile wearable health monitoring systems. One promising approach for addressing this challenge is to harvest the body heat energy using flexible thermoelectric generators, and printing is a low-cost technique for large-scale fabrication of flexible circuits and systems. This paper discusses the development of thermoelectric inks that can be used in the fabrication of thermoelectric generators, which can be used as sustainable power sources for mobile wearable health monitoring systems. The operation mechanism of thermoelectric generators for body heat harvesting is discussed, followed by the requirements on the properties of thermoelectric inks for the fabrication of printable thermoelectric generators. To achieve high thermoelectric figure of merit, we synthesized nano-structured thermoelectric materials with high Seebeck coefficient and low thermal conductivity, and developed surface functionalized carbon nanotubes that can be used as conducting agents for improving the electrical conductivity of thermoelectric inks.
- Published
- 2013
- Full Text
- View/download PDF
28. Motion artifact removal algorithm by ICA for e-bra: a women ECG measurement system
- Author
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Vijay K. Varadan, Sechang Oh, and Hyeokjun Kwon
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Holter monitor ,medicine.diagnostic_test ,Computer science ,Noise (signal processing) ,business.industry ,Independent component analysis ,Adaptive filter ,Least mean squares filter ,medicine ,Kurtosis ,Entropy (information theory) ,Computer vision ,cardiovascular diseases ,Artificial intelligence ,ECG Measurement ,business ,Algorithm ,Electrocardiography - Abstract
Wearable ECG(ElectroCardioGram) measurement systems have increasingly been developing for people who suffer from CVD(CardioVascular Disease) and have very active lifestyles. Especially, in the case of female CVD patients, several abnormal CVD symptoms are accompanied with CVDs. Therefore, monitoring women’s ECG signal is a significant diagnostic method to prevent from sudden heart attack. The E-bra ECG measurement system from our previous work provides more convenient option for women than Holter monitor system. The e-bra system was developed with a motion artifact removal algorithm by using an adaptive filter with LMS(least mean square) and a wandering noise baseline detection algorithm. In this paper, ICA(independent component analysis) algorithms are suggested to remove motion artifact factor for the e-bra system. Firstly, the ICA algorithms are developed with two kinds of statistical theories: Kurtosis, Endropy and evaluated by performing simulations with a ECG signal created by sgolayfilt function of MATLAB, a noise signal including 0.4Hz, 1.1Hz and 1.9Hz, and a weighed vector W estimated by kurtosis or entropy. A correlation value is shown as the degree of similarity between the created ECG signal and the estimated new ECG signal. In the real time E-Bra system, two pseudo signals are extracted by multiplying with a random weighted vector W, the measured ECG signal from E-bra system, and the noise component signal by noise extraction algorithm from our previous work. The suggested ICA algorithm basing on kurtosis or entropy is used to estimate the new ECG signal Y without noise component.
- Published
- 2013
- Full Text
- View/download PDF
29. Smart real-time cardiac diagnostic sensor systems for football players and soldiers under intense physical training
- Author
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Prashanth S. Kumar, Hyeokjun Kwon, Pratyush Rai, Sechang Oh, and Vijay K. Varadan
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Football players ,medicine.medical_specialty ,medicine.diagnostic_test ,biology ,business.industry ,Athletes ,education ,Training (meteorology) ,medicine.disease ,biology.organism_classification ,Sudden cardiac death ,Increased risk ,Physical therapy ,Medicine ,Diagnostic data ,cardiovascular diseases ,business ,Electrocardiography - Abstract
Sudden cardiac death (SCD) and acute myocardial infarctions (AMIs) have been reported to be up to 7.6 times higher in rate of occurrence during intense exercise as compared to sedentary activities. The risk is high in individuals with both diagnosed as well as occult heart diseases. Recently, SCDs have been reported with a high rate of occurrence among young athletes and soldiers who routinely undergo vigorous training. Prescreening Electrocardiograms (ECG) and echocardiograms have been suggested as potential means of detecting any cardiac abnormalities prior to intense training to avoid the risk of SCDs, but the benefits of this approach are widely debated. Moreover, the increased risk of SCDs and AMIs during training or exercise suggests that ECGs are of much greater value when acquired real-time during the actual training. The availability of immediate diagnostic data will greatly reduce the time taken to administer the appropriate resuscitation. Important factors to consider in the implementation of this solution are: - cost of overall system, accuracy of signals acquired and unobtrusive design. In this paper, we evaluate a system using printed sensors made of inks with functional properties to acquire ECGs of athletes and soldiers during physical training and basic military training respectively. Using Zigbee, we show that athletes and soldiers can be monitored in real time, simultaneously.
- Published
- 2013
- Full Text
- View/download PDF
30. Wireless health monitoring helmet for football players to diagnose concussion and track fatigue
- Author
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Sechang Oh, Mouli Ramasamy, Vijay K. Varadan, Hyeokjun Kwon, Prashanth S. Kumar, and Pratyush Rai
- Subjects
Football players ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Traumatic brain injury ,Brain dysfunction ,fungi ,Electroencephalography ,medicine.disease ,Physical medicine and rehabilitation ,Concussion ,Wireless ,Medicine ,business ,Cumulative effect ,Simulation ,Brain function - Abstract
Football players are regularly exposed to violent impacts. Concussions are mild traumatic brain injuries that are one of the most common injuries experienced by football players. These concussions are often overlooked by football players themselves and the clinical criteria used to diagnose them. The cumulative effect of these mild traumatic brain injuries can cause long-term residual brain dysfunctions. In addition, an athlete’s fatigue level should be monitored to prevent any secondary injuries due to over exertion. Nitric Oxide acts as a metabolic adjustment factor that controls the flow of oxygen in blood and the contraction/relaxation of muscles. Fatigue can be evaluated by measuring the concentration change of nitric oxide in blood. However, measuring the concentration of nitric oxide in blood is not feasible during exercise. Nevertheless, the degree of fatigue can be measured with SpO2 during exercise because the change of nitric oxide also influences the SpO2. In this paper, we propose a wireless health monitoring helmet to diagnose concussions and evaluate fatigue in real time and on the field. The helmet is equipped with sensors and a transmitter module. As sensors, textile based electrodes are used to sense EEG and oximeter sensors are used to derive SpO2. The sensed physiological signals are amplified and processed in the transmitter module. The processed signals are transmitted to a server using Zigbee wireless communication. The EEG signals are classified to diagnose concussion or any abnormality of brain function. In conclusion, the system can monitor and diagnose concussions and evaluate fatigue in football players in real time by measuring their EEGs and SpO2.
- Published
- 2013
- Full Text
- View/download PDF
31. Printable thermoelectric devices and conductive patterns for medical applications
- Author
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Jungmin Lee, Vijay K. Varadan, Hyunjung Kim, Linfeng Chen, and Sang H. Choi
- Subjects
Fabrication ,Materials science ,Thermoelectric generator ,business.industry ,Conductive ink ,Thermoelectric effect ,Wireless ,Nanotechnology ,Electricity ,business ,Thermoelectric materials ,Electrical conductor - Abstract
Remote point-of-care is expected to revolutionize the modern medical practice, and many efforts have been made for the development of wireless health monitoring systems for continuously detecting the physiological signals of patients. To make the remote point-of-care generally accepted and widely used, it is necessary to develop cost-effective and durable wireless health monitoring systems. Printing technique will be helpful for the fabrication of high-quality and low-cost medical devices and systems because it allows high-resolution and high-speed fabrication, low material consumption and nano-sized patterning on both flexible and rigid substrates. Furthermore, application of thermoelectric generators can replace conventional batteries as the power sources for wireless health monitoring systems because thermoelectric generators can convert the wasted heat or the heat from nature into electricity which is required for the operation of the wireless health monitoring systems. In this research, we propose the concept of printable thermoelectric devices and conductive patterns for the realization of more portable and cost-effective medical devices. To print thermoelectric generators and conductive patterns on substrates, printing inks with special characteristics should be developed. For the development of thermoelectric inks, nano-structured thermoelectric materials are synthesized and characterized; and for the development of conductive inks, two kinds of surface treated carbon nanotubes are used as active materials.
- Published
- 2012
- Full Text
- View/download PDF
32. Synthesis of iron oxide nanotubes and their applications in neuroscience and drug delivery
- Author
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Jining Xie, Kiran R. Aatre, Justin Yancey, Malathi Srivatsan, Vijay K. Varadan, and Linfeng Chen
- Subjects
Ferrofluid ,Materials science ,Biocompatibility ,Scanning electron microscope ,Iron oxide ,Maghemite ,Thermal treatment ,Hematite ,engineering.material ,chemistry.chemical_compound ,chemistry ,visual_art ,visual_art.visual_art_medium ,engineering ,Neuroscience ,Magnetite - Abstract
This paper reports the synthesis of three types of iron oxide nanotubes, including hematite (α-Fe 2 O 3 ), maghemite (γ-Fe 2 O 3 ) and magnetite (Fe 3 O 4 ), and their applications in neuroscience and drug delivery. Two methods, template-assisted thermal decomposition method and hydrothermal method, were used for synthesizing hematite nanotubes, and maghemite nanotubes were obtained from hematite nanotubes by thermal treatment. Template-assisted filtering method was used for synthesizing magnetite nanotubes from ferrofluid. The crystalline, morphology and magnetic properties of the synthesized iron oxide nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM), respectively. The biocompatibility of the synthesized hematite nanotubes was confirmed by the survival and differentiation of PC12 cells in the presence of the hematite nanotubes coupled to nerve growth factor (NGF). The capacity of hematite nanotubes for coupling and leasing NGF was confirmed by cultivating PC12 cells in the presence of NGF-loaded hematite nanotubes. The drug loading and release capabilities of hematite nanotubes were tested by using ibuprofen sodium salt (ISS) as a drug model. Based on the experimental results presented in this paper, it can be concluded that iron oxide nanotubes have good biocompatibility with neurons, could be used in guding neurite growth, and are promising candidates for drug delivery.
- Published
- 2012
- Full Text
- View/download PDF
33. Carbon nanotubes polymer nanoparticles inks for healthcare textile
- Author
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Pratyush Rai, Jungmin Lee, Gyanesh N. Mathur, and Vijay K. Varadan
- Subjects
Conductive polymer ,Textile ,Nanocomposite ,Materials science ,business.industry ,Nanotechnology ,Carbon nanotube ,law.invention ,law ,Printed electronics ,Conductive ink ,Screen printing ,Electronics ,business - Abstract
Healthcare textiles are ambient health monitoring systems that can contribute towards medical aid as well as general fitness of the populace. These are textile based products that have sensor systems mounted on them or are electrically functionalized to act as sensors. While embedded sensor chipsets and connection wires have been shown as working prototypes of this concept, there is a need for seamless integration of sensor technologies without hindering the inherent properties of the textile. Screen printing or stamping with electrically conductive inks have been demonstrated as technologies for fabricating electronics on flexible substrates. They are applicable to textile manufacturing as well. Printing technology allows for fabrication of nanocomposite based electronics elements in a bottom-up fashion. This has advantages such as low material consumption, high speed fabrication and low temperature processing. In this research, Multi-Wall Carbon Nanotubes (MWCNTs) and polyaniline nanoparticles (PANP) core shell based nanocomposites were synthesized and formulated into colloidal ink. Printed MWCNTs-PANP traces were electrically characterized and compared with traces made with those made by other composites such as Silver, and Carbon Black. The nanocomposite based inks are compared for proposed applications as sensor systems and conductive tracks on smart textile for pervasive wireless healthcare system that can be mass produced using low cost printing processes.
- Published
- 2012
- Full Text
- View/download PDF
34. Nanocomposite electrodes for smartphone enabled healthcare garments: e-bra and smart vest
- Author
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Vijay K. Varadan, Prashanth S. Kumar, Pratyush Rai, Hyeokjun Kwon, and Sechang Oh
- Subjects
Nanocomposite ,Materials science ,business.industry ,Wearable computer ,Clothing ,law.invention ,Bluetooth ,law ,Embedded system ,Health care ,Electronic engineering ,Ecg signal ,business ,Healthcare data ,Point of care - Abstract
The financial burden of hospital readmissions and treatment of chronic cardiac diseases are global concerns. Point of Care (POC) has been presented as an elegant solution for healthcare cost reduction. However, large scale adoption of POC systems requires an intuitive, unobtrusive and easy to use health monitoring system from patient’s perspective. Healthcare textiles are sensor systems mounted on textile platform that function as wearable unobtrusive health monitoring systems. Although much work has been done in the development and demonstration of textile mounted monitoring systems, material and production costs are still high. Nanomaterials based devices and technology can be employed in these healthcare textiles for improved electrical characteristics of the sensors, lowered cost due to less material consumption and compatibility to varied manufacturing techniques. Carbon nanotube composite ink based printable conductive electrodes is such a textile adaptable nanomaterial technology. Screen printed Nanocomposite electrodes made of carbon nanotubes and an acrylic polymer can be used in undergarments like vests and brassieres, for cardiac biopotential (Electrocardiography, ECG) sensing. A Bluetooth module and a smartphone can then be used to provide cyber-infrastructure connectivity for the healthcare data from these healthcare garments. They can be used to monitor young or elderly recuperating /convalescent patients either in hospital or at home, or they can be used by young athletes to monitor important physiological parameters to better design their training or fitness program. In this study, we evaluate screen printed CNT-acrylic Nanocomposite electrodes for ECG signal quality and any CNT leaching hazard that might lead to skin toxicity.
- Published
- 2012
- Full Text
- View/download PDF
35. Wireless telemedicine systems for diagnosing sleep disorders with Zigbee star network topology
- Author
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Vijay K. Varadan, Hyeokjun Kwon, and Sechang Oh
- Subjects
Star network ,Sleep Stages ,medicine.diagnostic_test ,business.industry ,Transmitter ,Sleep apnea ,Polysomnography ,Network topology ,medicine.disease ,Embedded system ,medicine ,Sleep (system call) ,Sleep study ,business ,Computer network - Abstract
Good sleep is critical for one's overall physical and mental health but more than 50 million Americans have experienced or are suffering from sleep disorders. Nevertheless, 85% of them remain undiagnosed or untreated. They can lead to chronic diseases. Sleep disorders are diagnosed through polysomnography, also known as sleep study, performed in a sleep laboratory overnight. This perturbs his/her daily sleep routine, and consequently, an accurate diagnosis cannot be made. Many companies have been developing home sleep test systems to reduce the cost of sleep studies and provide a more convenience solution to patients. The category of the system varies as type II, type III and type IV according to the type of sleep study. Current systems cannot be easily extended from one type to include a higher type. A patient who has a type III system to diagnose sleep apnea should additionally purchase a type II system which has functions that overlap with a type III system, to evaluate sleep stages. In this paper, we propose a wireless telemedicine system for easy extension of channels using the start network topology of the Zigbee protocol. The HST system consists of two wireless HST devices with a Zigbee module, a wireless HST receiver with both a Zigbee and a Wi-Fi module, and a sever which monitors/saves the physiological signals. One transmitter provides 5 channels for 2x EOG, 2x EEG and EMG to evaluate sleep stages. The other transmitter provides 5 additional channels for ECG, nasal air flow, body position, abdominal/chest efforts and oxygen saturation to diagnose sleep apnea. These two transmitters, acting as routers, and the receiver as a coordinator form a Zigbee star network. The data from each transmitter in the receiver are retransmitted to the monitoring unit through Wi-Fi. By building a star network with Zigbee, channels can be easily extended so that low level systems can be upgraded to higher level systems by simply adding the necessary channels. In addition, the proposed system provides real time monitoring of physiological signals at remote locations using Wi-Fi.
- Published
- 2012
- Full Text
- View/download PDF
36. Smart healthcare textile sensor system for unhindered-pervasive health monitoring
- Author
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Gyanesh N. Mathur, Sechang Oh, Prashanth S. Kumar, Megha Agarwal, Vijay K. Varadan, Pratyush Rai, and Hyeokjun Kwon
- Subjects
Textile ,Computer science ,business.industry ,Health care ,Sphygmomanometer ,Medical diagnosis ,business ,Communications system ,Signal ,Computer hardware - Abstract
Simultaneous monitoring of physiological parameters- multi-lead Electrocardiograph (ECG), Heart rate variability, and blood pressure- is imperative to all forms of medical treatments. Using an array of signal recording devices imply that the patient will have to be confined to a bed. Textiles offer durable platform for embedded sensor and communication systems. The smart healthcare textile, presented here, is a mobile system for remote/wireless data recording and conditioning. The wireless textile system has been designed to monitor a patient in a non-obstructive way. It has a potential for facilitating point of care medicine and streamlining ambulatory medicine. The sensor systems were designed and fabricated with textile based components for easy integration on textile platform. An innovative plethysmographic blood pressure monitoring system was designed and tested as an alternative to inflatable blood pressure sphygmomanometer. Flexible dry electrodes technology was implemented for ECG. The sensor systems were tested and conditioned to daily activities of patients, which is not permissible with halter type systems. The signal quality was assessed for it applicability to medical diagnosis. The results were used to corroborate smart textile sensor system's ability to function as a point of care system that can provide quality healthcare.
- Published
- 2012
- Full Text
- View/download PDF
37. Synthesis and characterization of thermoelectric ink for renewable energy applications
- Author
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Jungmin Lee, Vijay K. Varadan, Hyun Jung Kim, Sang H. Choi, and Sechang Oh
- Subjects
Fabrication ,Materials science ,Inkwell ,Nanotechnology ,Epoxy ,Thermoelectric materials ,chemistry.chemical_compound ,Thermoelectric generator ,chemistry ,visual_art ,Thermoelectric effect ,visual_art.visual_art_medium ,Polystyrene ,Wetting - Abstract
Printing technology enables continuous, high-speed fabrication of thermoelectric devices on both flexible and rigid substrates. The printing process, patterns, substrates and inks need to be investigated and optimized for the fabrication of these printable thermoelectric devices. Ink design in terms of physical properties like wettability and viscosity, choice of binder and filler materials is a critical part in the fabrication of printable thermoelectric devices, especially printable p-type materials and n-type materials to make p-n junctions. In this study, we described the mechanism of thermoelectric generator and synthetic method of thermoelectric materials for printing inks. And the Bi2Te3 / epoxy resin and Bi2Te3 / polystyrene printing inks were prepared with high energy ball milled Bi2Te3 powder.
- Published
- 2012
- Full Text
- View/download PDF
38. Preparation and characterization of nano-composites with carbon nanotubes and core-shell type polyaniline for the conductive colloidal ink
- Author
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Vijay K. Varadan and Jungmin Lee
- Subjects
Conductive polymer ,Materials science ,Nanocomposite ,Polyaniline nanofibers ,Nanoparticle ,Nanotechnology ,Carbon nanotube ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Printed electronics ,Conductive ink ,Polyaniline - Abstract
Printing method for electronics elements fabrication has attractive advantages such as low material consumption, high speed fabrication, and low temperature process. The stable conductive ink is the most important factor for the fabrication of printed electronics elements with high resolution. These materials are widely used as fillers in conductive inks; metal particles, conductive polymers, and carbon materials. Among these materials, the carbon nanotubes (CNTs) are extremely attractive filler for printed electronics due to its superior electrical properties, extra high mechanical properties, and excellent chemical stability. In this research, nano-composites which are composed of multi wall carbon nanotubes (MWCNTs) and polyaniline core-shell type particles were synthesized and formulated into electrically conductive colloidal inks. The poly(acrylonitrile-co-itaconic acid-co-methylacrylate) nanoparticles were used as cores. And this core was coated with polyaniline. The surface treatments for MWCNTs were applied to make the stable nano-composites. The experimental conditions were optimized to achieve high miscibility between MWCNTs and polyaniline coated particles. Their structure and surface morphology of the nanocomposites were characterized by Scanning Electron Microscopy. And four point probe automatic resistivity meter was used to measure the conductivities of the nanocomposites.
- Published
- 2012
- Full Text
- View/download PDF
39. Front Matter: Volume 8344
- Author
-
Vijay K. Varadan
- Subjects
Volume (thermodynamics) ,Mechanics ,Geology ,Front (military) - Published
- 2012
- Full Text
- View/download PDF
40. Music close to one's heart: heart rate variability with music, diagnostic with e-bra and smartphone
- Author
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Gyanesh N. Mathur, Shantala Hegde, Vijay K. Varadan, Prashanth S. Kumar, and Pratyush Rai
- Subjects
Music therapy ,Multimedia ,Musical ,Single-subject design ,computer.software_genre ,behavioral disciplines and activities ,humanities ,Empirical research ,Modulation (music) ,Heart rate ,Heart rate variability ,Active listening ,Psychology ,human activities ,computer ,Cognitive psychology - Abstract
Music is a powerful elicitor of emotions. Emotions evoked by music, through autonomic correlates have been shown to cause significant modulation of parameters like heart rate and blood pressure. Consequently, Heart Rate Variability (HRV) analysis can be a powerful tool to explore evidence based therapeutic functions of music and conduct empirical studies on effect of musical emotion on heart function. However, there are limitations with current studies. HRV analysis has produced variable results to different emotions evoked via music, owing to variability in the methodology and the nature of music chosen. Therefore, a pragmatic understanding of HRV correlates of musical emotion in individuals listening to specifically chosen music whilst carrying out day to day routine activities is needed. In the present study, we aim to study HRV as a single case study, using an e-bra with nano-sensors to record heart rate in real time. The e-bra developed previously, has several salient features that make it conducive for this study- fully integrated garment, dry electrodes for easy use and unrestricted mobility. The study considers two experimental conditions:- First, HRV will be recorded when there is no music in the background and second, when music chosen by the researcher and by the subject is playing in the background.
- Published
- 2012
- Full Text
- View/download PDF
41. Size and shape dependence of the electrochemical properties of hematite nanoparticles and their applications in lithium ion batteries
- Author
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Vijay K. Varadan, Gyanesh N. Mathur, Gaojun Wang, and Linfeng Chen
- Subjects
Materials science ,Scanning electron microscope ,Nanoparticle ,chemistry.chemical_element ,Carbon black ,Hematite ,Lithium-ion battery ,Chemical engineering ,chemistry ,visual_art ,Electrode ,visual_art.visual_art_medium ,Particle ,Lithium - Abstract
Hematite nanoparticles are a type of promising electrode active materials for lithium ion batteries due to their low cost and high specific capacity. However, the cycling performances of hematite nanoparticles are not as good as those of the conventional electrode active materials for lithium ion batteries. This paper reports the study on the relationship between the electrochemical properties and the particle sizes and shapes, aiming to optimize the electrochemical properties of hematite nanoparticles for their applications in lithium ion batteries. Three types of hematite nanoparticles were compared, including hematite nanospheres with an average diameter of 200 nm, hematite nanoflakes with an average maximum dimension of 200 nm, and hematite nanospheres with an average diameter of 30 nm. Their crystalline structures were characterized by X-ray diffraction (XRD) and their particle morphologies were analyzed by scanning electron microscopy (SEM). Composite electrode materials were made from hematite nanoparticles with carbon black as the conducting material and PVDF as the binding material (hematite : carbon black : PVDF = 70 : 15 : 15). Prototype lithium ion batteries (CR2032 button cells) were assembled with the composite electrodes as cathodes, metal lithium as anodes, and Celgard 2400 porous membrane as separators. It was found that in the first few cycles, the specific discharge capacity of hematite nanospheres with an average diameter of 30 nm is higher than those of the other two, while after first seven cycles, the specific discharge capacity of hematite nanospheres with an average diameter of 30 nm is lower than those of the other two. Possible approaches for improving the cycling performance and rate capacity of hematite nanoparticles are discussed at the end of this paper.
- Published
- 2012
- Full Text
- View/download PDF
42. The Zigbee wireless ECG measurement system design with a motion artifact remove algorithm by using adaptive filter and moving weighted factor
- Author
-
Vijay K. Varadan, Hyeokjun Kwon, and Sechang Oh
- Subjects
Artifact (error) ,medicine.diagnostic_test ,Noise (signal processing) ,Computer science ,Low-pass filter ,Filter (signal processing) ,Signal ,Adaptive filter ,Analog signal ,Distortion ,medicine ,Signal transfer function ,ECG Measurement ,Algorithm ,Electrocardiography ,Linear filter - Abstract
The Electrocardiogram(ECG) signal is one of the bio-signals to check body status. Traditionally, the ECG signal was checked in the hospital. In these days, as the number of people who is interesting with periodic their health check increase, the requirement of self-diagnosis system development is being increased as well. Ubiquitous concept is one of the solutions of the self-diagnosis system. Zigbee wireless sensor network concept is a suitable technology to satisfy the ubiquitous concept. In measuring ECG signal, there are several kinds of methods in attaching electrode on the body called as Lead I, II, III, etc. In addition, several noise components occurred by different measurement situation such as experimenter's respiration, sensor's contact point movement, and the wire movement attached on sensor are included in pure ECG signal. Therefore, this paper is based on the two kinds of development concept. The first is the Zibee wireless communication technology, which can provide convenience and simpleness, and the second is motion artifact remove algorithm, which can detect clear ECG signal from measurement subject. The motion artifact created by measurement subject's movement or even respiration action influences to distort ECG signal, and the frequency distribution of the noises is around from 0.2Hz to even 30Hz. The frequencies are duplicated in actual ECG signal frequency, so it is impossible to remove the artifact without any distortion of ECG signal just by using low-pass filter or high-pass filter. The suggested algorithm in this paper has two kinds of main parts to extract clear ECG signal from measured original signal through an electrode. The first part is to extract motion noise signal from measured signal, and the second part is to extract clear ECG by using extracted motion noise signal and measured original signal. The paper suggests several techniques in order to extract motion noise signal such as predictability estimation theory, low pass filter, a filter including a moving weighted factor, peak to peak detection, and interpolation techniques. In addition, this paper introduces an adaptive filter in order to extract clear ECG signal by using extracted baseline noise signal and measured signal from sensor.
- Published
- 2012
- Full Text
- View/download PDF
43. Wireless brain-machine interface using EEG and EOG: brain wave classification and robot control
- Author
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Prashanth S. Kumar, Vijay K. Varadan, Sechang Oh, and Hyeokjun Kwon
- Subjects
medicine.diagnostic_test ,Computer science ,business.industry ,Brain activity and meditation ,Wearable computer ,Electroencephalography ,Human–robot interaction ,Robot control ,medicine ,Robot ,Computer vision ,Artificial intelligence ,Robust control ,business ,Simulation ,Brain–computer interface - Abstract
A brain-machine interface (BMI) links a user's brain activity directly to an external device. It enables a person to control devices using only thought. Hence, it has gained significant interest in the design of assistive devices and systems for people with disabilities. In addition, BMI has also been proposed to replace humans with robots in the performance of dangerous tasks like explosives handling/diffusing, hazardous materials handling, fire fighting etc. There are mainly two types of BMI based on the measurement method of brain activity; invasive and non-invasive. Invasive BMI can provide pristine signals but it is expensive and surgery may lead to undesirable side effects. Recent advances in non-invasive BMI have opened the possibility of generating robust control signals from noisy brain activity signals like EEG and EOG. A practical implementation of a non-invasive BMI such as robot control requires: acquisition of brain signals with a robust wearable unit, noise filtering and signal processing, identification and extraction of relevant brain wave features and finally, an algorithm to determine control signals based on the wave features. In this work, we developed a wireless brain-machine interface with a small platform and established a BMI that can be used to control the movement of a robot by using the extracted features of the EEG and EOG signals. The system records and classifies EEG as alpha, beta, delta, and theta waves. The classified brain waves are then used to define the level of attention. The acceleration and deceleration or stopping of the robot is controlled based on the attention level of the wearer. In addition, the left and right movements of eye ball control the direction of the robot.
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- 2012
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44. Lithium iron phosphates as cathode materials in lithium ion batteries for electric vehicles
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Vijay K. Varadan, Gyanesh N. Mathur, Linfeng Chen, and Gaojun Wang
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Materials science ,Lithium vanadium phosphate battery ,Lithium iron phosphate ,chemistry.chemical_element ,Electrochemistry ,Lithium-ion battery ,Cathode ,Anode ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Ionic conductivity ,Lithium - Abstract
Olivine-structured lithium iron phosphates are promising cathode materials in the development of high power lithium ion batteries for electric vehicles. However, the low electronic conductivity and ionic conductivity of lithium iron phosphates hinder their commercialization pace. This work aims to verify the approaches for improving the electrochemical properties of lithium iron phosphates. In this work, sol-gel method was used to synthesize carbon coated lithium iron phosphates and nickel doped lithium iron phosphates, and their particle sizes were controlled in the nanometer to sub-micrometer range. The crystalline structures of the synthesized lithium iron phosphates were characterized by X-ray diffraction, and their morphologies were analyzed by scanning electron microscopy. To study their electrochemical properties, prototype lithium ion batteries were assembled with the synthesized lithium iron phosphates as cathode active materials, and with lithium metal discs as the anodes, and the discharge / charge properties and cycling behaviors of the prototype batteries were tested at different rates. The synthesized lithium iron phosphate materials exhibited high capacity and high cycling stability. It was confirmed that particle size reduction, carbon coating and metal doping are three effective approaches for increasing the conductivity of lithium iron phosphates, and thus improving their electrochemical properties. Experimental results show that by combing the three approaches for improving the electrochemical properties, lithium iron phosphate composites with characteristics favorable for their applications in lithium ion batteries for electric vehicles can be developed, including high specific capacity, high rate capacity, flat discharge voltage plateau and high retention ratio.
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- 2012
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45. Wireless remote monitoring system for sleep apnea
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Vijay K. Varadan, Sechang Oh, and Hyeokjun Kwon
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medicine.diagnostic_test ,business.industry ,Transmitter ,Continuous monitoring ,Sleep apnea ,Polysomnography ,medicine.disease ,Sleep deprivation ,medicine ,Wireless ,Sleep (system call) ,Medical emergency ,Sleep study ,medicine.symptom ,business - Abstract
Sleep plays the important role of rejuvenating the body, especially the central nervous system. However, more than thirty million people suffer from sleep disorders and sleep deprivation. That can cause serious health consequences by increasing the risk of hypertension, diabetes, heart attack and so on. Apart from the physical health risk, sleep disorders can lead to social problems when sleep disorders are not diagnosed and treated. Currently, sleep disorders are diagnosed through sleep study in a sleep laboratory overnight. This involves large expenses in addition to the inconvenience of overnight hospitalization and disruption of daily life activities. Although some systems provide home based diagnosis, most of systems record the sleep data in a memory card, the patient has to face the inconvenience of sending the memory card to a doctor for diagnosis. To solve the problem, we propose a wireless sensor system for sleep apnea, which enables remote monitoring while the patient is at home. The system has 5 channels to measure ECG, Nasal airflow, body position, abdominal/chest efforts and oxygen saturation. A wireless transmitter unit transmits signals with Zigbee and a receiver unit which has two RF modules, Zigbee and Wi-Fi, receives signals from the transmitter unit and retransmits signals to the remote monitoring system with Zigbee and Wi-Fi, respectively. By using both Zigbee and Wi-Fi, the wireless sensor system can achieve a low power consumption and wide range coverage. The system's features are presented, as well as continuous monitoring results of vital signals.
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- 2011
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46. Development of diagnosis and treatment technology for brain disease using quantum material and nano probe pin device
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Uhn Lee, Yeon-Joon Park, Sang H. Choi, Kyo D. Song, and Vijay K. Varadan
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Power transmission ,Curing (food preservation) ,Computer science ,Nano ,Electronic engineering ,Brain disease - Abstract
New medical device technology is essential for diagnosing, monitoring, and curing wide spectrum of diseases, anomalies and inflictions. For neural applications, currently available devices are generally limited to either a curing or a probing function. In this paper we review the technology requirements for new neural probe and cure device technology currently under development. The concept of probe-pin device that integrates the probes for neurochemistry, neuroelectricity, temperature and pressure into a single embodiment with a wireless power transmission was designed for the purpose of deep brain feedback stimulation (DBFS) with insitu neural monitoring. The probe considered for monitoring neurochemistry is a microspectrometer. The feature and size of micro-spectrometer are defined for the DBFS device. Two types of wireless power transmission technology were studied for DBFS device operation. The test results of pig skin showed that both power transmission technologies demonstrated the feasibility of power feed through human tissue.
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- 2011
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47. Synthesis of hematite and maghemite nanotubes and study of their applications in neuroscience and drug delivery
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Malathi Srivatsan, Sahitya Chetan, Justin Yancey, Kiran R. Aatre, Jining Xie, Linfeng Chen, and Vijay K. Varadan
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Materials science ,Biocompatibility ,Magnetism ,Scanning electron microscope ,Maghemite ,Nanotechnology ,Thermal treatment ,engineering.material ,Hematite ,law.invention ,Chemical engineering ,law ,visual_art ,Drug delivery ,engineering ,visual_art.visual_art_medium ,Electron microscope - Abstract
This report discusses our work on synthesis of hematite and maghemite nanotubes, analysis of their biocompatibility with pheochromocytoma cells (PC12 cells), and study of their applications in the culture of dorsal root ganglion (DRG) neurons and the delivery of ibuprofen sodium salt (ISS) drug model. Two methods, template-assisted thermal decomposition method and hydrothermal method, were used for synthesizing hematite nanotubes, and maghemite nanotubes were obtained from the synthesized hematite nanotubes by thermal treatment. The crystalline, morphology and magnetic properties of the hematite and maghemite nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM), respectively. The biocompatibility of the synthesized hematite nanotubes was confirmed by the survival and differentiation of PC12 cells in the presence of the hematite nanotubes coupled to nerve growth factor (NGF). To study the combined effects of the presence of magnetic nanotubes and external magnetic fields on neurite growth, laminin was coupled to hematite and maghemite nanotubes, and DRG neurons were cultured in the presence of the treated nanotubes with the application of external magnetic fields. It was found that neurons can better tolerate external magnetic fields when magnetic nanotubes were present. Close contacts between nanotubes and filopodia that were observed under SEM showed that the nanotubes and the growing neurites interacted readily. The drug loading and release capabilities of hematite nanotubes synthesized by hydrothermal method were tested by using ibuprofen sodium salt (ISS) as a drug model. Our experimental results indicate that hematite and maghemite nanotubes have good biocompatibility with neurons, could be used in regulating neurite growth, and are promising vehicles for drug delivery.
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- 2011
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48. E-bra with nanosensors, smart electronics and smart phone communication network for heart rate monitoring
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Prashanth S. Kumar, Vijay K. Varadan, Gyanesh N. Mathur, Pratyush Rai, Lauren Kegley, and Sechang Oh
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Signal processing ,Focus (computing) ,medicine.diagnostic_test ,Computer science ,business.industry ,Cardiovascular health ,Heart activity ,Computer security ,computer.software_genre ,Signal ,Telecommunications network ,Heart rate ,medicine ,Heart rate variability ,Electronics ,Telecommunications ,business ,computer ,Electrocardiography - Abstract
Heart related ailments have been a major cause for deaths in both men and women in United States. Since 1985, more women than men have died due to cardiac or cardiovascular ailments for reasons that are not well understood as yet. Lack of a deterministic understanding of this phenomenon makes continuous real time monitoring of cardiovascular health the best approach for both early detection of pathophysiological changes and events indicative of chronic cardiovascular diseases in women. This approach requires sensor systems to be seamlessly mounted on day to day clothing for women. With this application in focus, this paper describes a e-bra platform for sensors towards heart rate monitoring. The sensors, nanomaterial or textile based dry electrodes, capture the heart activity signals in form Electrocardiograph (ECG) and relay it to a compact textile mountable amplifier-wireless transmitter module for relay to a smart phone. The ECG signal, acquired on the smart phone, can be transmitted to the cyber space for post processing. As an example, the paper discusses the heart rate estimation and heart rate variability. The data flow from sensor to smart phone to server (cyber infrastructure) has been discussed. The cyber infrastructure based signal post processing offers an opportunity for automated emergency response that can be initiated from the server or the smartphone itself. Detailed protocols for both the scenarios have been presented and their relevance to the present emergency healthcare response system has been discussed.
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- 2011
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49. Printable low-cost sensor systems for healthcare smart textiles
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Hyeokjun Kwon, Gyanesh N. Mathur, Pratyush Rai, Prashanth S. Kumar, Vijay K. Varadan, and Sechang Oh
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Textile ,Computer science ,business.industry ,Robustness (computer science) ,Printed electronics ,Embedded system ,Data logger ,Health care ,Screen printing ,Wearable computer ,Reuse ,business - Abstract
Smart textiles-based wearable health monitoring systems (ST-HMS) have been presented as elegant solutions to the requirements of individuals across a wide range of ages. They can be used to monitor young or elderly recuperating /convalescent patients either in hospital or at home, or they can be used by young athletes to monitor important physiological parameters to better design their training or fitness program. Business and academic interests, all over the world, have fueled a great deal of work in the development of this technology since 1990. However, two important impediments to the development of ST-HMS are:-integration of flexible electrodes, flexible sensors, signal conditioning circuits and data logging or wireless transmission devices into a seamless garment and a means to mass manufacture the same, while keeping the costs low. Roll-to-roll printing and screen printing are two low cost methods for large scale manufacturing on flexible substrates and can be extended to textiles as well. These two methods are, currently, best suited for planar structures. The sensors, integrated with wireless telemetry, facilitate development of a ST-HMS that allows for unobtrusive health monitoring. In this paper, we present our results with planar screen printable sensors based on conductive inks which can be used to monitor EKG, abdominal respiration effort, blood pressure, pulse rate and body temperature. The sensor systems were calibrated, and tested for sensitivity, reliability and robustness to ensure reuse after washing cycles.
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- 2011
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50. Nanotechnology research and development for military and industrial applications
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John V. Foreman, April S. Brown, J. Keith Roberts, Tuan Vo-Dinh, Sihon H. Crutcher, Mark G. Temmen, Yang Yang, Mohan Sanghadasa, Paul B. Ruffin, John H. Callahan, Christina Brantley, Vijay K. Varadan, Paul R. Ashley, Henry O. Everitt, Tong-Ho Kim, William M. Chew, Eric Webster, Larry C. Warren, Pae C. Wu, Christopher G. Khoury, Devlin Hayduke, and Eugene Edwards
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Propellant ,Units of measurement ,Engineering ,Missile ,Exploit ,business.industry ,Aviation ,Advanced composite materials ,Computer data storage ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Nanotechnology ,Rocket motor ,business - Abstract
Researchers at the Army Aviation and Missile Research, Development, and Engineering Center (AMRDEC) have initiated multidiscipline efforts to develop nano-based structures and components for insertion into advanced missile, aviation, and autonomous air and ground systems. The objective of the research is to exploit unique phenomena for the development of novel technology to enhance warfighter capabilities and produce precision weapons. The key technology areas that the authors are exploring include nano-based microsensors, nano-energetics, nano-batteries, nano-composites, and nano-plasmonics. By integrating nano-based devices, structures, and materials into weaponry, the Army can revolutionize existing (and future) missile systems by significantly reducing the size, weight and cost. The major research thrust areas include the development of chemical sensors to detect rocket motor off-gassing and toxic industrial chemicals; the development of highly sensitive/selective, self-powered miniaturized acoustic sensors for battlefield surveillance and reconnaissance; the development of a minimum signature solid propellant with increased ballistic and physical properties that meet insensitive munitions requirements; the development of nano-structured material for higher voltage thermal batteries and higher energy density storage; the development of advanced composite materials that provide high frequency damping for inertial measurement units' packaging; and the development of metallic nanostructures for ultraviolet surface enhanced Raman spectroscopy. The current status of the overall AMRDEC Nanotechnology research efforts is disclosed in this paper. Critical technical challenges, for the various technologies, are presented. The authors' approach for overcoming technical barriers and achieving required performance is also discussed. Finally, the roadmap for each technology, as well as the overall program, is presented.
- Published
- 2011
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