Low-Power High Data-Rate Wireless Transmitter For Medical Implantable Devices

RÉSUMÉ Les émetteurs-récepteurs radiofréquences (RF) sont les circuits de communication les plus communs pour établir des interfaces home-machine dédiées aux dispositifs médicaux implantables. Par exemple, la surveillance continue de paramètres de santé des patients souffrant d'épilepsie nécessite un étage de communication sans-fil capable de garantir un transfert de données rapide, en temps réel, à faible puissance tout en étant implémenté dans un faible volume. La consommation de puissance des dispositifs implantables implique une durée de vie limitée de la batterie qui nécessite alors une chirurgie pour son remplacement, a moins qu’une technique de transfert de puissance sans-fil soit utilisée pour recharger la batterie ou alimenter l’implant a travers les tissus humains. Dans ce projet, nous avons conçu, implémenté et testé un émetteur RF à faible puissance et haut-débit de données opérant à 902-928 MHz de la bande fréquentielle industrielle-scientifique-médicale (ISM) d’Amérique du Nord. Cet émetteur fait partie d'un système de communication bidirectionnel dédié à l’interface sans-fil des dispositifs électroniques implantables et mettables et bénéficie d’une nouvelle approche de modulation par déplacement de fréquence (FSK). Les différentes étapes de conception et d’implémentation de l'architecture proposée pour l'émetteur sont discutées et analysées dans cette thèse. Les blocs de circuits sont réalisés suivant les équations dérivées de la modulation FSK proposée et qui mènera à l'amélioration du débit de données et de la consommation d'énergie. Chaque bloc est implémenté de manière à ce que la consommation d'énergie et la surface de silicium nécessaires soient réduites. L’étage de modulation et le circuit mélangeur ne nécessitent aucun courant continu grâce à leur structure passive.Parmi les circuits originaux, un oscillateur en quadrature contrôlé-en-tension (QVCO) de faible puissance est réalisé pour générer des signaux différentiels en quadrature, rail-à-rail avec deux gammes de fréquences principales de 0.3 à 11.5 MHz et de 3 à 40 MHz. L'étage de sortie énergivore est également amélioré et optimisé pour atteindre une efficacité de puissance de ~ 37%. L'émetteur proposé a été implémenté et fabriqué à la suite de simulations post-layout approfondies.----------ABSTRACT Wireless radio frequency (RF) transceivers are the most common communication front-ends used to realize the human-machine interfaces of medical devices. Continuous monitoring of body behaviour of patients suffering from Epilepsy, for example, requires a wireless communication front-end capable of maintaining a fast, real-time and low-power data communication while implemented in small size. Power budget limitation of the implantable and wearable medical devices obliges engineers to replace or recharge the battery cell through frequent medial surgeries or other power transfer techniques. In this project, a low-power and high data-rate RF transmitter (Tx) operating at North-American Industrial-Scientific-Medical (ISM) frequency band (902-928 MHz) is designed, implemented and tested. This transmitter is a part of a bi-directional transceiver dedicated to the wireless interface of implantable and wearable medical devices and benefits from a new efficient Frequency-Shift Keying (FSK) modulation scheme. Different design and implementation stages of the proposed transmitter architecture are discussed and analyzed in this thesis. The building blocks are realized according to the equations derived from the proposed FSK modulation, which results in improvement in data-rate and power consumption. Each block is implemented such that the power consumption and needed chip area are lowered while the modulation block and the mixer circuit require no DC current due to their passive structure. Among the original blocks, a low-power quadrature voltage-controlled oscillator (QVCO) is achieved to provide differential quadrature rail-to-rail signals with two main frequency ranges of 0.3-11.5 MHz and 3-40 MHz. The power-hungry output stage is also improved and optimized to achieve power efficiency of ~37%. The proposed transmitter was implemented and fabricated following deep characterisation by post-layout simulation. Both simulation and measurement results are discussed and compared with state-of-the-art transmitters showing the contribution of this work in this very popular research field. The Figure-Of-Merit (FOM) was improved, meaning mainly increasing the data-rate and lowering the power consumption of the circuit. The transmitter is implemented using 130 nm CMOS technology with 1.2 V supply voltage. A data-rate of 8 Mb/s was measured while consuming 1.4 mA and resulting in energy consumption of 0.21 nJ/b. The fabricated transmitter has small active silicon area of less than 0.25 mm2

Temperature Compensation in OTA-C integrators using a Resistive Bridge

In this thesis, a new technique for temperature compensation of G m -C filters is presented. An Operational Transconductance Amplifier (OTA) as well as the output buffers is implemented in STMicroelectronics 9O-nm technology with 1.2 V supply voltage. Variation of a gate-capacitance implemented by an NMOS transistor with respect to temperature is investigated. Using negative feedback the G m -cells' transconductance is locked to the reciprocal of a resistance array. Temperature behaviour of the G m -C filter is examined by the behaviour of a G m -C integrator without receiving an external frequency reference. Temperature dependency of the G m /C ratio, which determines the unity-gain frequency of the integrator. is minimized by arranging the temperature dependency of the resistors. Unique properties of a proposed resistive bridge allow for the synthesis of temperature coefficients beyond the range of coefficients of constituent elements. With a set of practical elements a variation of only 0.66% in G m /C has been achieved over -40°C to 120°C

The Investigation of Cultural Factors Affecting the Sustainable Development in Yazd, Iran

Culture is the main factor and is regarded as the engine of sustainable development that without considering it, development programs would not be successful. Cultural factors play a vital role in sustainable development and sustainable development planning should be based on different cultures. Yazd in many years had considerable share in the field of cultural and religious in the country. But a glance at the current situation of the city that perhaps the cultural climate of the city has been neglected, the continuation of historical role and identity of the city, as well as improvement the lives of residents of the city without understanding the cultural factors affecting sustainable development does not seem possible. In the cultural issues, there are various indices that affect on development. In this paper, combining some of the models include the development of culture and the experiences of other countries and division of the Supreme Council of Cultural Revolution, four basic indicators with the sub- indicators for each indicator have been specified. Given the descriptive nature of the investigation, in order to collect required data and test questions the questionnaire has been used. The first part of questionnaire consisted of demographic questions. Other questions have been considered to measure the components and based on assumptions of the study. Questionnaires were distributed on the basis of statistical sampling in Yazd city. The research method is descriptive survey. The study population in our research included Yazd citizens over 18 years old with a history of more than two years residency in the city of Yazd. Based on the results of the questionnaires, the hypothesis of effectiveness of two indicators of identity and social order was accepted and effectiveness of the two indicators of involvement and cultural engagement and social capital was not approved. In the end, some strategies of urban management approach to effectiveness of affective cultural factors on sustainable development have been provided

ANALYTIC APPROXIMATE SOLUTION FOR NONLINEAR DYNAMICMODELING OF THE ROTATING ELASTIC 2D BEAM WITH A SINGLE CRACK

In this paper, the 2D lateral vibration analysis of a rotating cracked beam as a rotary structure is investigated through the Homotopy perturbation analysis and compared with the numerical Newmark-beta (Nβ) algorithm. The structure and crack are modeled as the Euler-Bernoulli (EB) theory and simple torsional spring, respectively. The nonlinear equations of motion are derived using Galerkin and the Assumed Mode Method (AMM). The system’s stability is analyzed through phase plane and time response for different angular velocities of the base, initial values, external disturbances, crack stiffness, and locations. A comparative study presents simulation results for free (first nonlinear frequency) and forced vibration. It is shown that the proposed semi-analytical approach is beneficial as it provides a benchmark for a more precise analysis and further investigation of cracked rotary structures

Effects of Postbiotics from Food Probiotic and Protective Cultures on Proliferation and Apoptosis in HCT-116 Colorectal Cancer Cells

Background and Objective: Postbiotics are microbial-derived soluble products, which are released during the growth and fermentation process of beneficial microorganisms in gastrointestinal tract, food and complex microbiological culture systems (cell-free supernatant or extracellular extract) or after cell lysis (intracellular extract). Colorectal cancer is one of the most common cancers within the leading causes of cancer mortality worldwide, which can be associated with a defeated gastrointestinal barrier. In this study, potential functionality of the extracellular and intracellular extracts of probiotics (Latilactobacillus sakei, LS) and protective culture (FreshQ®, FQ) on proliferation and cell survival of HCT-116 colon cancer epithelial cells was investigated. Material and Methods: Probiotic bacteria were cultivated in de Man, Rogosa and Sharpe broth and then postbiotics was isolated by centrifugation and sonication. The achieved solutions were lyophilized and stored until use. Moreover, HCT-116 cells were exposed to various concentrations of Latilactobacillus sakei and FreshQ® extracts (1.25-40 mg ml-1) for 24 h and then effects of these products on cell cytotoxicity, proliferation and apoptosis were investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing and AO/EB assays. Results and Conclusion: Extracellular and intracellular extracts of Latilactobacillus sakei and FreshQ the decreased in cell viability based on the postbiotic concentrations (p≤0.05), while cell proliferation was inhibited by extracellular and intracellular extracts of Latilactobacillus sakei and FreshQ® in wound healing assay. Results showed that postbiotics could induce apoptosis evidenced by acridine orange/ethidium bromide staining. In summary, Latilactobacillus sakei and FreshQ® postbiotics are able to decrease cell viability and proliferation and enhance apoptosis in HCT-116 colorectal cancer cells. In addition, FreshQ® postbiotics seemed more potent than that Latilactobacillus sakei postbiotics did. Conflict of interest: The authors declare no conflict of interest

Robust and fast sliding-mode control for a DC-DC current-source parallel-resonant converter

Modern DC-DC resonant converters are normally built around a voltage-source series-resonant converter. This study aims to facilitate the practical use of current-source parallel-resonant converters due to their outstanding properties. To this end, this study presents a sliding-mode control scheme, which provides the following features to the closed-loop system: (i) high robustness to external disturbances and parameter variations and (ii) fast transient response during large and abrupt load changes. In addition, a design procedure for determining the values of the control parameters is presented. The theoretical contributions of this study are experimentally validated by selected tests on a laboratory prototype.Peer ReviewedPreprin

Investigating the factors affecting the survival rate in patients with COVID-19 : A retrospective cohort study

Funding Information: Conflicts of Interest: None declared Funding: This study was financially supported by the Deputy of Research and Technology of Iran University of Medical Sciences, Tehran, Iran (Grant no. 17571).Peer reviewedPublisher PD

Language Model Crossover: Variation through Few-Shot Prompting

This paper pursues the insight that language models naturally enable an intelligent variation operator similar in spirit to evolutionary crossover. In particular, language models of sufficient scale demonstrate in-context learning, i.e. they can learn from associations between a small number of input patterns to generate outputs incorporating such associations (also called few-shot prompting). This ability can be leveraged to form a simple but powerful variation operator, i.e. to prompt a language model with a few text-based genotypes (such as code, plain-text sentences, or equations), and to parse its corresponding output as those genotypes' offspring. The promise of such language model crossover (which is simple to implement and can leverage many different open-source language models) is that it enables a simple mechanism to evolve semantically-rich text representations (with few domain-specific tweaks), and naturally benefits from current progress in language models. Experiments in this paper highlight the versatility of language-model crossover, through evolving binary bit-strings, sentences, equations, text-to-image prompts, and Python code. The conclusion is that language model crossover is a promising method for evolving genomes representable as text

Relationship between Distribution of Coronary Artery Lesions and Renal Artery Stenosis in Patients Undergoing Simultaneous Coronary and Renal Angiography

Aims We evaluated the relationship between distribution of lesions in coronary tree and atherosclerotic renal artery stenosis (RAS). Methods and Results Data collected prospectively on 500 consecutive patients who underwent simultaneous renal angiography following coronary angiography. Overall prevalence of RAS was 26.2% (131 patients). Significant (≥ 50% luminal diameter stenosis) RAS was present in 70 patients (14%). In 346 individuals of the study population, significant CAD was present (69.2%). Significant RAS was more common (18.4%) in this group. Older age, higher intra-arterial systolic blood pressure (SBP) and pulse pressure (PP) at the time of catheterization, and 3-vessel coronary artery disease (CAD) were associated with significant RAS in univariate analysis. Relationship between involved locations of coronary arteries [Left anterior descending (LAD), left circumflex (LCX), Right Coronary Artery (RCA), and their ostioproximal portions] and RAS were significant except for left main (LM) disease. In multivariate model, age more than 62 years, SBP greater than 150 mmHg, PP in excess of 60 mmHg and RCA involvement were independent predictors of significant RAS. Conclusion Simultaneous renal angiography following coronary angiography might be justified in patients with significant RCA disease who are older with increased levels of intra-arterial SBP and PP

Frequency-modulation control of a DC/DC current-source parallel-resonant converter

This paper proposes a frequency-modulation control scheme for a dc/dc current-source parallel-resonant converter with two possible configurations. The basic configuration comprises an external voltage loop, an internal current loop, and a frequency modulator: the voltage loop is responsible for regulating the output voltage, the current loop makes the system controllable and limits the input current, and the modulator provides robustness against variations in resonant component values. The enhanced configuration introduces the output inductor current as a feed-forward term and clearly improves the transient response to fast load changes. The theoretical design of these control schemes is performed systematically by first deriving their small-signal models and second using Bode diagram analysis. The actual performance of the proposed control schemes is experimentally validated by testing on a laboratory prototype.Peer ReviewedPostprint (author's final draft