A scalable 2.9mW 1Mb/s eTextiles body area network transceiver with remotely powered sensors and bi-directional data communication

Advances in sensor design have made ambulatory health monitoring possible and have created the need for low-power communication systems to replace bulkier traditional links. Micropower sensors should also be powered by a non-local energy source for system miniaturization and long life. Recently proposed communication systems using wireless body area networks [1,2] and body-coupled communication [3] suffer from high path loss around the human body for efficient remote power delivery. In contrast, eTextiles are becoming an increasingly popular technology for efficiently powering and communicating with such sensors [4-6] due to wide coverage around the human body combined with low path loss and comfort of use.MIT Masdar Program (Cooperative Agreement 196F/002/707/102f/70/9374

A low power, reconfigurable fabric body area network for healthcare applications

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 105-110).Body Area Networks (BANs) are gaining prominence for their capability to revolutionize medical monitoring, diagnosis and treatment. This thesis describes a BAN that uses conductive fabrics (e-textiles) worn by the user to act as a power distribution and data communication network to sensors on the user's body. The network is controlled by a central hub in the form of a Base Station, which can either be a standalone device or can be embedded inside one of the user's portable electronic devices like a cellphone. Specifications for a Physical (PHY) layer and a Medium Access Control (MAC) layer have been developed that make use of the asymmetric energy budgets between the base station and sensor nodes in the network. The PHY layer has been designed to be suitable for the unique needs of such a BAN, namely easy reconfigurability, fault-tolerance and efficient energy and data transfer at low power levels. This is achieved by a mechanism for dividing the network into groups of sensors. The co-designed MAC layer is capable of supporting a wide variety of sensors with different data rate and network access requirements, ranging from EEG monitors to temperature sensors. Circuits have been designed at both ends of the network to transmit, receive and store power and data in appropriate frequency bands. Digital circuits have been designed to implement the MAC protocols. The base station and sensor nodes have been implemented in standard 180nm 1P6M CMOS process, and occupy an area 4.8mm2 and 3.6mm2 respectively. The base station has a minimum power consumption of 2.86mW, which includes the power transmitter, modulation and demodulation circuitry. The sensor nodes can recover up to 33.6paW power to supply to the biomedical signal acquisition circuitry with peak transfer efficiency of 1.2%.by Nachiket Venkappayya Desai.S.M

The Gravity Collective: A Search for the Electromagnetic Counterpart to the Neutron Star-Black Hole Merger GW190814

We present optical follow-up imaging obtained with the Katzman Automatic Imaging Telescope, Las Cumbres Observatory Global Telescope Network, Nickel Telescope, Swope Telescope, and Thacher Telescope of the LIGO/Virgo gravitational wave (GW) signal from the neutron star-black hole (NSBH) merger GW190814. We searched the GW190814 localization region (19 deg$^{2}$ for the 90th percentile best localization), covering a total of 51 deg$^{2}$ and 94.6% of the two-dimensional localization region. Analyzing the properties of 189 transients that we consider as candidate counterparts to the NSBH merger, including their localizations, discovery times from merger, optical spectra, likely host-galaxy redshifts, and photometric evolution, we conclude that none of these objects are likely to be associated with GW190814. Based on this finding, we consider the likely optical properties of an electromagnetic counterpart to GW190814, including possible kilonovae and short gamma-ray burst afterglows. Using the joint limits from our follow-up imaging, we conclude that a counterpart with an $r$-band decline rate of 0.68 mag day$^{-1}$, similar to the kilonova AT 2017gfo, could peak at an absolute magnitude of at most $-17.8$ mag (50% confidence). Our data are not constraining for ''red'' kilonovae and rule out ''blue'' kilonovae with $M>0.5 M_{\odot}$ (30% confidence). We strongly rule out all known types of short gamma-ray burst afterglows with viewing angles $<$17$^{\circ}$ assuming an initial jet opening angle of $\sim$$5.2^{\circ}$ and explosion energies and circumburst densities similar to afterglows explored in the literature. Finally, we explore the possibility that GW190814 merged in the disk of an active galactic nucleus, of which we find four in the localization region, but we do not find any candidate counterparts among these sources.Comment: 86 pages, 9 figure

Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens

Global age-sex-specific fertility, mortality, healthy life expectancy (HALE), and population estimates in 204 countries and territories, 1950-2019 : a comprehensive demographic analysis for the Global Burden of Disease Study 2019

Background: Accurate and up-to-date assessment of demographic metrics is crucial for understanding a wide range of social, economic, and public health issues that affect populations worldwide. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 produced updated and comprehensive demographic assessments of the key indicators of fertility, mortality, migration, and population for 204 countries and territories and selected subnational locations from 1950 to 2019. Methods: 8078 country-years of vital registration and sample registration data, 938 surveys, 349 censuses, and 238 other sources were identified and used to estimate age-specific fertility. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate age-specific fertility rates for 5-year age groups between ages 15 and 49 years. With extensions to age groups 10–14 and 50–54 years, the total fertility rate (TFR) was then aggregated using the estimated age-specific fertility between ages 10 and 54 years. 7417 sources were used for under-5 mortality estimation and 7355 for adult mortality. ST-GPR was used to synthesise data sources after correction for known biases. Adult mortality was measured as the probability of death between ages 15 and 60 years based on vital registration, sample registration, and sibling histories, and was also estimated using ST-GPR. HIV-free life tables were then estimated using estimates of under-5 and adult mortality rates using a relational model life table system created for GBD, which closely tracks observed age-specific mortality rates from complete vital registration when available. Independent estimates of HIV-specific mortality generated by an epidemiological analysis of HIV prevalence surveys and antenatal clinic serosurveillance and other sources were incorporated into the estimates in countries with large epidemics. Annual and single-year age estimates of net migration and population for each country and territory were generated using a Bayesian hierarchical cohort component model that analysed estimated age-specific fertility and mortality rates along with 1250 censuses and 747 population registry years. We classified location-years into seven categories on the basis of the natural rate of increase in population (calculated by subtracting the crude death rate from the crude birth rate) and the net migration rate. We computed healthy life expectancy (HALE) using years lived with disability (YLDs) per capita, life tables, and standard demographic methods. Uncertainty was propagated throughout the demographic estimation process, including fertility, mortality, and population, with 1000 draw-level estimates produced for each metric. Findings: The global TFR decreased from 2·72 (95% uncertainty interval [UI] 2·66–2·79) in 2000 to 2·31 (2·17–2·46) in 2019. Global annual livebirths increased from 134·5 million (131·5–137·8) in 2000 to a peak of 139·6 million (133·0–146·9) in 2016. Global livebirths then declined to 135·3 million (127·2–144·1) in 2019. Of the 204 countries and territories included in this study, in 2019, 102 had a TFR lower than 2·1, which is considered a good approximation of replacement-level fertility. All countries in sub-Saharan Africa had TFRs above replacement level in 2019 and accounted for 27·1% (95% UI 26·4–27·8) of global livebirths. Global life expectancy at birth increased from 67·2 years (95% UI 66·8–67·6) in 2000 to 73·5 years (72·8–74·3) in 2019. The total number of deaths increased from 50·7 million (49·5–51·9) in 2000 to 56·5 million (53·7–59·2) in 2019. Under-5 deaths declined from 9·6 million (9·1–10·3) in 2000 to 5·0 million (4·3–6·0) in 2019. Global population increased by 25·7%, from 6·2 billion (6·0–6·3) in 2000 to 7·7 billion (7·5–8·0) in 2019. In 2019, 34 countries had negative natural rates of increase; in 17 of these, the population declined because immigration was not sufficient to counteract the negative rate of decline. Globally, HALE increased from 58·6 years (56·1–60·8) in 2000 to 63·5 years (60·8–66·1) in 2019. HALE increased in 202 of 204 countries and territories between 2000 and 2019

Circuits for efficient and secure power delivery in distributed applications

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.Cataloged from PDF version of thesis.Includes bibliographical references (pages 159-167).The growing number of widely distributed IoT devices presents new challenges in power delivery. Existing frameworks for charging electronic devices, be they wired or wireless, either end up limiting the amount devices can be shrunk due to the size of standardized connectors or end up restricting their free placement due to their reliance on charging mats. The large amounts of vital data IoT devices gather and their heavily distributed nature also makes it important to protect them against unauthorized or malicious charging that might be aimed at damaging and/or stealing data from them. This thesis focuses on developing circuits and architectures to enable a more distributed and secure approach to charging such devices by exploring two topics in particular - energy harvesting and wireless charging. First, a converter for harvesting power from thermoelectric generators (TEGs) is presented. The converter is capable of cold-starting from a bipolar supply as low as 40 mV, making it suitable for applications where the direction of heat flow from which energy is harvested could be bi-directional. Upon cold-starting from such low voltages, the converter transitions to a high-efficiency mode in steady state that achieves up to 60% efficiency while delivering 110 pW of power. With the goal of building a fully integrated transformer in the future, techniques for modeling an integrated transformer for optimal harvester performance have also been presented. Second, a receiver for device-to-device wireless charging is presented. The receiver dynamically measures the end-to-end system efficiency adjusts the ac input impedance it presents to the wireless power transmission system in order to track the maximum efficiency point. It also employs an inverter-inspired resonant rectifier that overall results in a 13.8% total energy saving for the transmitter with when the received power is 650 mW. Next, an adaptive rectifier control scheme for wireless power transfer that integrates linear regulation into the high-side switches of the rectifier is presented. This has the capability to reduce the area of an integrated converter by eliminating an additional LDO at the output of the rectifier. Additionally, the regulation technique presented results in lower system efficiency degradation when the output power is regulated below the maximum value. Finally, a wireless power receiver detuning technique is presented. Detuning allows the receiver to protect itself from harmful transients imposed by counterfeit or malicious chargers, by reducing the received power by up to 16 x. It also allows multiple receivers coupled to the same charger to co-operate in order to balance their received powers. Using this technique, the asymmetry in the output powers of two receivers at 4:1 distance ratios from the transmitter can be reversed.by Nachiket Venkappayya Desai.Ph. D

Design, Molecular Docking and Synthesis of Pyrazole-Oxadiazole in search of potent insecticidal agents

A series of sixteen substituted pyrazole oxadiazole derivatives are designed, synthesised and characterized by 1H NMR, 13C NMR and mass spectrometry. The ligands have been docked with Acetylcholine receptor to understand the binding efficiency and amino acids interactions, indicative of all of the sixteen molecules bind efficiently better than Fipronil and Pyrafluprole. These compounds will provide a lead for designing new compounds with improved insecticidal activity

A 25 mV-startup cold start system with on-chip magnetics for thermal energy harvesting

Thermal energy harvesting systems use boost converters for high-efficiency low voltage operation, but lack the ability for low voltage startup without off-chip transformers. We present a cold start system that uses integrated magnetics instead of external transformers in a Meissner Oscillator to start up from ultra low voltages, with a switched capacitor DC-DC circuit for additional voltage gain. The oscillator analysis with on-chip magnetics allows device co-optimization for low voltage operation, despite 1000x lower inductance values than off-chip transformers. Co-optimized on-chip transformer and depletion-mode NMOS start up from 25 mV driven directly by a sourcemeter, or 50 mV with a 4.7 Ω series resistance, for the lowest integrated electrical startup. The co-packaged system provides proof of concept for integration with boost converter circuits on a single die to have a fully-integrated low voltage startup solution for thermal energy harvesting applications, without using off-chip transformers