Smart Devices and Systems for Wearable Applications

Wearable technologies need a smooth and unobtrusive integration of electronics and smart materials into textiles. The integration of sensors, actuators and computing technologies able to sense, react and adapt to external stimuli, is the expression of a new generation of wearable devices. The vision of wearable computing describes a system made by embedded, low power and wireless electronics coupled with smart and reliable sensors - as an integrated part of textile structure or directly in contact with the human body. Therefore, such system must maintain its sensing capabilities under the demand of normal clothing or textile substrate, which can impose severe mechanical deformation to the underlying garment/substrate. The objective of this thesis is to introduce a novel technological contribution for the next generation of wearable devices adopting a multidisciplinary approach in which knowledge of circuit design with Ultra-Wide Band and Bluetooth Low Energy technology, realization of smart piezoresistive / piezocapacitive and electro-active material, electro-mechanical characterization, design of read-out circuits and system integration find a fundamental and necessary synergy. The context and the results presented in this thesis follow an “applications driven” method in terms of wearable technology. A proof of concept has been designed and developed for each addressed issue. The solutions proposed are aimed to demonstrate the integration of a touch/pressure sensor into a fabric for space debris detection (CApture DEorbiting Target project), the effectiveness of the Ultra-Wide Band technology as an ultra-low power data transmission option compared with well known Bluetooth (IR-UWB data transmission project) and to solve issues concerning human proximity estimation (IR-UWB Face-to-Face Interaction and Proximity Sensor), wearable actuator for medical applications (EAPtics project) and aerospace physiology countermeasure (Gravity Loading Countermeasure Skinsuit project)

Optimal readout schemes in SPAD-based time-correlated event detection sensor for quantum imaging applications

open3MOS SPAD imagers are potentially good candidates for detection of entangled photons in Quantum Imaging applications thanks to their sub-nanosecond time-resolved capabilities and highly parallel readout. In this context, the low number of photons that are typically detected corresponds to a very sparse data matrix. A full readout of raw data is therefore a waste of time and power. We have implemented a sensor architecture to improve the efficiency of the observation up to 8.46% in a TDC-based pixel structure. A tunable current source is used per pixel to establish a global current. This global current presents a real-time status of the whole pixel array in terms of triggered SPADs. The proposed solution requires minimal extra pixel electronics, with little impact on the fill factor and allows an observation rate of up to 8.5 Mfps.Zarghami, Majid; Gasparini, Leonardo; Stoppa, DavidZarghami, Majid; Gasparini, Leonardo; Stoppa, Davi

Design of a cantilever-based system for genomic applications

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Fast and simple spectral FLIM for biochemical and medical imaging.

Spectrally resolved fluorescence lifetime imaging microscopy (λFLIM) has powerful potential for biochemical and medical imaging applications. However, long acquisition times, low spectral resolution and complexity of λFLIM often narrow its use to specialized laboratories. Therefore, we demonstrate here a simple spectral FLIM based on a solid-state detector array providing in-pixel histrogramming and delivering faster acquisition, larger dynamic range, and higher spectral elements than state-of-the-art λFLIM. We successfully apply this novel microscopy system to biochemical and medical imaging demonstrating that solid-state detectors are a key strategic technology to enable complex assays in biomedical laboratories and the clinic.A.E. thanks the EPSRC for the initial funding of the project (EP/F044011/1) from 2009 to 2011. M.P. and L.D.C. were supported by a Programme Grant to A.R.V. from the UK Medical Research Council (MRC). This project was also supported by the MRC’s grant-in-aid to the Cancer Unit, Cambridge (A.E., A.R.V.). C.F.K acknowledges funding from the MRC (grant MR/K015850/1), the Wellcome Trust (grant 089703/Z/09/Z) and the EPSRC (EP/L015889/1).This is the author accepted manuscript. The final version is available from the Optical Society of America via http://dx.doi.org/10.1364/OE.23.02351

Torus equivariant K-stability

It is conjectured that to test the K-polystability of a polarised variety it is enough to consider test-configurations which are equivariant with respect to a torus in the automorphism group. We prove partial results towards this conjecture. We also show that it would give a new proof of the K-polystability of constant scalar curvature polarised manifolds

Forward and backward digit span difficulties in children with specific learning disorder

This study examined performance in the forward and backward digit span task of the Wechsler Intelligence Scale for Children–Fourth Edition (WISC–IV) in a large group of children with specific learning disorder (SLD) as compared with a group of typically developing children matched for age and sex. Our results further support the hypothesis that the intellectual difficulties of children with SLD involve working memory in the forward digit span task to a greater extent than in the backward digit span task. The correlation of the two spans with a General Ability Index (GAI) was similar in SLD, and smaller in magnitude than in typically developing children. Despite a GAI within normal range, children with SLD had difficulty with both digit span tasks, but more so for forward span. This pattern was similar for different SLD profiles with clinical diagnoses of dyslexia and mixed disorder, but the impairments were more severe in the latter. Age differences were also investigated, demonstrating larger span impairment in older children with SLD than in younger

Optimization of Pinned Photodiode Pixels for High-Speed Time of Flight Applications

We discuss optimizations of pinned photodiode (PPD) pixels for indirect time of flight sensors. We focus on the transfer-gate and dumping gate regions optimization, on the PPD dimension and shape to assure fast lateral charge transfer and on the epitaxial layer thickness for a good tradeoff between fast vertical charge transfer and high quantum efficiency at near infrared region. The overall performance of the pixel is quantified by the demodulation contrast of the pixel at specific frequencies. The operation frequency of the device is determined by the required ambiguity range of the application and the required distance noise. In order to reach a reasonable distance noise, the pixel needs to allow modulation frequencies up to 100 MHz. In this paper, we present TCAD simulation and experimental data on demodulation contrast, impulse response time, and quantum efficiency of $10 \times 10\,\,\mu \text{m}$ pixels. We introduce a setup for impulse response measurement and we compare this to the demodulation contrast. We also discuss the optimization of the dump gate and dump diffusion. With the best pixel we measured a quantum efficiency of about 45% at 850 nm, a demodulation contrast of 47% at 80 MHz, and an impulse response time < 5 ns

A 180-nm CMOS Time-of-Flight 3-D Image Sensor

Abstract-We report on the design and the experimental characterization of a new 3-D image sensor, based on a new 120-nm CMOS-compatible photo-detector, which features an internal demodulation mechanism effective up to high frequencies. The distance range covered by our proof-of-concept device spans from 1-m to a few meter, and the resolution is about 1-cm

Evaluation of polygenic risk scores for breast and ovarian cancer risk prediction in BRCA1 and BRCA2 mutation carriers

Background: Genome-wide association studies (GWAS) have identified 94 common single-nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk and 18 associated with ovarian cancer (OC) risk. Several of these are also associated with risk of BC or OC for women who carry a pathogenic mutation in the high-risk BC and OC genes BRCA1 or BRCA2. The combined effects of these variants on BC or OC risk for BRCA1 and BRCA2 mutation carriers have not yet been assessed while their clinical management could benefit from improved personalized risk estimates. Methods: We constructed polygenic risk scores (PRS) using BC and OC susceptibility SNPs identified through population-based GWAS: for BC (overall, estrogen receptor [ER]-positive, and ER-negative) and for OC. Using data from 15 252 female BRCA1 and 8211 BRCA2 carriers, the association of each PRS with BC or OC risk was evaluated using a weighted cohort approach, with time to diagnosis as the outcome and estimation of the hazard ratios (HRs) per standard deviation increase in the PRS. Results: The PRS for ER-negative BC displayed the strongest association with BC risk in BRCA1 carriers (HR = 1.27, 95% confidence interval [CI] = 1.23 to 1.31, P = 8.2 x 10(53)). In BRCA2 carriers, the strongest association with BC risk was seen for the overall BC PRS (HR = 1.22, 95% CI = 1.17 to 1.28, P = 7.2 x 10(-20)). The OC PRS was strongly associated with OC risk for both BRCA1 and BRCA2 carriers. These translate to differences in absolute risks (more than 10% in each case) between the top and bottom deciles of the PRS distribution; for example, the OC risk was 6% by age 80 years for BRCA2 carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS. Conclusions: BC and OC PRS are predictive of cancer risk in BRCA1 and BRCA2 carriers. Incorporation of the PRS into risk prediction models has promise to better inform decisions on cancer risk management