DESIGN AND IMPLEMENTATION OF ENERGY HARVESTING CIRCUITS FOR MEDICAL DEVICES

Technological enhancements in a low-power CMOS process have promoted enhancement of advanced circuit design techniques for sensor related electronic circuits such as wearable and implantable sensor systems as well as wireless sensor nodes (WSNs). In these systems, the powering up the electronic circuits has remained as a major problem because battery technologies are not closely following the technological improvements in semiconductor devices and processes thus limiting the number of sensor electronics modules that can be incorporated in the design of the system. In addition, the traditional batteries can leak which can cause serious health hazards to the patients especially when using implantable sensors. As an alternative solution to prolonging the life of battery or to mitigate serious health problems that can be caused by battery, energy harvesting technique has appeared to be one of the possible solutions to supply power to the sensor electronics. As a result, this technique has been widely studied and researched in recent years. In a conventional sensor system, the accessible space for batteries is limited, which restricts the battery capacity. Therefore, energy harvesting has become an attractive solution for powering the sensor electronics. Power can be scavenged from ambient energy sources such as electromagnetic signal, wind, solar, mechanical vibration, radio frequency (RF), and thermal energy etc. Among these common ambient sources, RF and piezoelectric vibration-based energy scavenging systems have received a great deal of attention because of their ability to be integrated with sensor electronics modules and their moderate available power density. In this research, both RF and piezoelectric vibration-based energy harvesting systems have been studied and implemented in 130 nm standard CMOS process

A Low Power Integrated Circuit for Implantable Biosensor Incorporating an On-Chip FSK Modulator

Medical care has been significantly improved in recent years due to tremendous technological advancement in the field of CMOS technology. Among those improvements, integrated circuit design and sensing techniques have brought to the doctors more flexibility and accuracy of examinations of their patients. For example, a diabetic patient needs to visit a hospital on a regular basis for the examination and proper treatment. However, with the tremendous advancement in electronic technology, a patient can soon monitor his or her own blood glucose level at home or at office with an implantable sensor which can also trigger insulin pump attached to the body. The insulin delivery system can be precisely controlled by the electronics embedded in the implantable device. In this thesis, a low power integrated circuit for the implantable biosensor incorporating an on-chip FSK modulator is presented. This design has been fabricated using AMI 0.5-μm CMOS process available through MOSIS. The simulation and test results are also presented to verify its operation

Vitamin C promotes self-renewal of rat embryonic stem cell

Embryonic stem cell lines (ESCs) can be used for regenerative medicine and drug discovery since they can form any type of cell in the body and self-renew indefinitely. Nowadays, rat animals appear to be more valuable in the field of biomedicine, than mouse model organisms, in terms of their body size, blood system, brain, disease symptoms and others. Thus, rat ESC (rESC) self-renewal and pluripotency mechanisms should be investigated rigorously. Although various cell signalling pathways responsible for mouse ESC (mESC) maintenance have been studied, very little is discovered about rESC. In addition, when ESCs are cultured in the 2i medium, rESCs display higher levels of differentiation genes (e.g. GATA4), compared to mESCs. Esteban et al. (2010) reported that Vitamin C improves formation of induced pluripotent stem (iPS) cell colonies. Here, we utilised Vitamin C activity to determine if this factor can reduce the spontaneous differentiation of rESCs and shift them to a more naïve pluripotent state. Our experimental works consist of three main parts, and various research techniques will be employed such as ES cell culture, siRNA transfection, morphological analysis, qRT-PCR and flow cytometry. Thus, we will identify if Vitamin C can improve rESC self-renewal and restricts differentiation, and subsequently we will determine how Vitamin C regulates self-renewal. Our project provides new insight into the mechanisms by which Vitamin C promotes rESC self-renewal

Cultivating Spirulina maxima: Innovative Approaches

This chapter reports an annual production of Spirulina (Arthrospira) maxima in Ansan, South Korea (37.287°N, 126.833°E) with temperate four seasons climate for testing industrial application. Construction on pilot plant of semi-open raceway system (ORS) with each 20 ton culture volume has been established in early 2011 based on building information modeling (BIM). An optimized design of pilot culture system for microalgae scale-up culture in temperate area and details of culture was presented. In scale-up trials using two ORSs, the strain displayed satisfactory annual growth under batch condition. In an annual trial, average biomass concentration was recorded at 0.99 ± 0.16 g/L, which showed stable productivity in a year. Maximum concentration was estimated at 1.418 ± 0.09 g/L in August, while minimum production was estimated at 0.597 ± 0.05 g/L in October. Despite insufficient solar radiation and nutrients, ORS was favorable for S. maxima production. The technical strategies contribute to the annual production of S. maxima in this region: controlling the culture temperature, reducing production cost, and retrospective climatic data-based BIM construction of the greenhouse. Consequently, pilot production of S. maxima was feasible in Korean climates, a region previously thought to be outside its geographic limits

Stretchable organic optoelectronic sensorimotor synapse

Emulation of human sensory and motor functions becomes a core technology in bioinspired electronics for next-generation electronic prosthetics and neurologically inspired robotics. An electronic synapse functionalized with an artificial sensory receptor and an artificial motor unit can be a fundamental element of bioinspired soft electronics. Here, we report an organic optoelectronic sensorimotor synapse that uses an organic optoelectronic synapse and a neuromuscular system based on a stretchable organic nanowire synaptic transistor (s-ONWST). The voltage pulses of a self-powered photodetector triggered by optical signals drive the s-ONWST, and resultant informative synaptic outputs are used not only for optical wireless communication of human-machine interfaces but also for light-interactive actuation of an artificial muscle actuator in the same way that a biological muscle fiber contracts. Our organic optoelectronic sensorimotor synapse suggests a promising strategy toward developing bioinspired soft electronics, neurologically inspired robotics, and electronic prostheses.

Ultrasonographic evaluation of tracheal collapse in dogs

Tracheal ultrasonography was performed to measure the width of the tracheal ring shadow and to assess the clinical relevance of these measurements for identifying tracheal collapse. The first tracheal ring width (FTRW) and thoracic inlet tracheal ring width (TITRW) were measured on both expiration and inspiration. The mean of the FTRW width (129 dogs) was greater in expiration (10.97 ± 1.02 mm, p = 0.001) than that in inspiration (9.86 ± 1.03 mm). For 51 normal dogs, the mean of the TITRW width was greater in expiration (9.05 ± 1.52 mm, p = 0.001) than in inspiration (8.02 ± 1.43 mm). For 78 tracheal collapse dogs, the mean of the TITRW width was greater in expiration (15.89 ± 1.01 mm, p = 0.001) than in inspiration (14.85 ± 1.17 mm). The TITRW/FTRW ratio of the normal dogs was higher (p = 0.001) in expiration (0.81 ± 0.09) than that in inspiration (0.79 ± 0.10). When compared between the normal and tracheal collapse dogs, the TITRW/FTRW ratio was also increased (p = 0.001) both in expiration (1.54 ± 0.09) and inspiration (1.47 ± 0.08), respectively. Based on these results, the cutoff level of the TITRW/FTRW ratio was statistically analyzed according to the receiver operating characteristic curve and it could be set at 1.16 in expiration and at 1.13 in inspiration. We have demonstrated that tracheal ultrasonography is a useful technique for the evaluation of tracheal collapse and it can be a supportive tool together with the radiographic findings for making the correct diagnosis

Whole‐body vibration for patients with nonalcoholic fatty liver disease: a 6‐month prospective study

Physical exercise has demonstrated benefits for managing nonalcoholic fatty liver disease (NAFLD). However, in daily life maintaining exercise without help may be difficult. A whole‐body vibration device (WBV) has been recently introduced as an exercise modality that may be suitable for patients who have difficulty engaging in exercise. We tested WBV in patients with NAFLD and estimated its effectiveness. We studied the effects of a 6‐month WBV program on hepatic steatosis and its underlying pathophysiology in 25 patients with NAFLD. Seventeen patients with NAFLD were designated as a control group. After WBV exercise, body weight in the study group decreased by only 2.5% compared with the control group. However, we found significant increases in muscle area (+2.6%) and strength (+20.5%) and decreases in fat mass (−6.8%). The hepatic (−9.9%) and visceral (−6.2%) fat content also significantly decreased (P < 0.05). There was substantial lowering of hepatic stiffness (−15.7%), along with improvements in the levels of inflammatory markers; tumor necrosis factor alpha (−50.9%), adiponectin (+12.0%), ferritin (−33.2%), and high‐sensitivity C‐reactive protein (−43.0%) (P < 0.05). These results suggest that WBV is an exercise option for patients with NAFLD that is effective, efficient, and convenient

A pathogen-derived metabolite induces microglial activation via odorant receptors

Microglia (MG), the principal neuroimmune sentinels in the brain, continuously sense changes in their environment and respond to invading pathogens, toxins, and cellular debris, thereby affecting neuroinflammation. Microbial pathogens produce small metabolites that influence neuroinflammation, but the molecular mechanisms that determine whether pathogen-derived small metabolites affect microglial activation of neuroinflammation remain to be elucidated. We hypothesized that odorant receptors (ORs), the largest subfamily of G protein-coupled receptors, are involved in microglial activation by pathogen-derived small metabolites. We found that MG express high levels of two mouse ORs, Olfr110 and Olfr111, which recognize a pathogenic metabolite, 2-pentylfuran, secreted by Streptococcus pneumoniae. These interactions activate MG to engage in chemotaxis, cytokine production, phagocytosis, and reactive oxygen species generation. These effects were mediated through the G(alpha s)-cyclic adenosine monophosphate-protein kinase A-extracellular signal-regulated kinase and G(beta gamma)-phospholipase C-Ca2+ pathways. Taken together, our results reveal a novel interplay between the pathogen-derived metabolite and ORs, which has major implications for our understanding of microglial activation by pathogen recognition. Database Model data are available in the PMDB database under the accession number PM0082389.N