The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...

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A comprehensive review of zno materials and devices

Summary Background Since December, 2019, Wuhan, China, has experienced an outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epidemiological and clinical characteristics of patients with COVID-19 have been reported but risk factors for mortality and a detailed clinical course of illness, including viral shedding, have not been well described. Methods In this retrospective, multicentre cohort study, we included all adult inpatients (≥18 years old) with laboratory-confirmed COVID-19 from Jinyintan Hospital and Wuhan Pulmonary Hospital (Wuhan, China) who had been discharged or had died by Jan 31, 2020. Demographic, clinical, treatment, and laboratory data, including serial samples for viral RNA detection, were extracted from electronic medical records and compared between survivors and non-survivors. We used univariable and multivariable logistic regression methods to explore the risk factors associated with in-hospital death. Findings 191 patients (135 from Jinyintan Hospital and 56 from Wuhan Pulmonary Hospital) were included in this study, of whom 137 were discharged and 54 died in hospital. 91 (48%) patients had a comorbidity, with hypertension being the most common (58 [30%] patients), followed by diabetes (36 [19%] patients) and coronary heart disease (15 [8%] patients). Multivariable regression showed increasing odds of in-hospital death associated with older age (odds ratio 1·10, 95% CI 1·03–1·17, per year increase; p=0·0043), higher Sequential Organ Failure Assessment (SOFA) score (5·65, 2·61–12·23; p Interpretation The potential risk factors of older age, high SOFA score, and d-dimer greater than 1 μg/mL could help clinicians to identify patients with poor prognosis at an early stage. Prolonged viral shedding provides the rationale for a strategy of isolation of infected patients and optimal antiviral interventions in the future. Funding Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences; National Science Grant for Distinguished Young Scholars; National Key Research and Development Program of China; The Beijing Science and Technology Project; and Major Projects of National Science and Technology on New Drug Creation and Development.

Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study

Zinc oxide is a unique material that exhibits semiconducting and piezoelectric dual properties. Using a solid–vapour phase thermal sublimation technique, nanocombs, nanorings, nanohelixes/nanosprings, nanobelts, nanowires and nanocages of ZnO have been synthesized under specific growth conditions. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The nanostructures could have novel applications in optoelectronics, sensors, transducers and biomedical sciences. This article reviews the various nanostructures of ZnO grown by the solid–vapour phase technique and their corresponding growth mechanisms. The application of ZnO nanobelts as nanosensors, nanocantilevers, field effect transistors and nanoresonators is demonstrated.

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Zinc oxide nanostructures: growth, properties and applications

MUCKE aims to mine a large volume of images, to structure them conceptually and to use this conceptual structuring in order to improve large-scale image retrieval. The last decade witnessed important progress concerning low-level image representations. However, there are a number problems which need to be solved in order to unleash the full potential of image mining in applications. The central problem with low-level representations is the mismatch between them and the human interpretation of image content. This problem can be instantiated, for instance, by the incapability of existing descriptors to capture spatial relationships between the concepts represented or by their incapability to convey an explanation of why two images are similar in a content-based image retrieval framework. We start by assessing existing local descriptors for image classification and by proposing to use co-occurrence matrices to better capture spatial relationships in images. The main focus in MUCKE is on cleaning large scale Web image corpora and on proposing image representations which are closer to the human interpretation of images. Consequently, we introduce methods which tackle these two problems and compare results to state of the art methods. Note: some aspects of this deliverable are withheld at this time as they are pending review. Please contact the authors for a preview.

http://ieeexplore.ieee.org/iel2/4524/12820/00592460.pdf

Image Processing

Recent progress in processing and properties of ZnO

Near-threshold computing brings the promise of an order of magnitude improvement in energy efficiency over the current generation of microprocessors [1]. However, frequency degradation due to aggressive voltage scaling may not be acceptable across all single-threaded or performance-constrained applications. Enabling the processor to operate over a wide voltage range helps to achieve best possible energy efficiency while satisfying varying performance demands of the applications. This paper describes an IA-32 processor fabricated in 32nm CMOS technology [2], demonstrating a reliable ultra-low voltage operation and energy efficient performance across the wide voltage range from 280mV to 1.2V.

A 280mV-to-1.2V wide-operating-range IA-32 processor in 32nm CMOS

A non-faradaic label-free cortisol biosensor was demonstrated using MoS2 nanosheets integrated into a nanoporous flexible electrode system. Low volume (1-5 μL) sensing was achieved through use of a novel sensor stack design comprised of vertically aligned metal electrodes confining semi-conductive MoS2 nanosheets. The MoS2 nanosheets were surface functionalized with cortisol antibodies towards developing an affinity biosensor specific to the physiological relevant range of cortisol (8.16 to 141.7 ng/mL) in perspired human sweat. Sensing was achieved by measuring impedance changes associated with cortisol binding along the MoS2 nanosheet interface using electrochemical impedance spectroscopy. The sensor demonstrated a dynamic range from 1-500 ng/mL with a limit of detection of 1 ng/mL. A specificity study was conducted using a metabolite expressed in human sweat, Ethyl Glucuronide. Continuous dosing studies were performed during which the sensor was able to discriminate between four cortisol concentration ranges (0.5, 5, 50, 500 ng/mL) for a 3+ hour duration. Translatability of the sensor was shown with a portable form factor device, demonstrating a comparable dynamic range and limit of detection for the sensor. The device demonstrated a R2 correlation value of 0.998 when comparing measurements to the reported impedance values of the benchtop instrumentation.

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Portable biosensor for monitoring cortisol in low-volume perspired human sweat

In situ Ga-doped ZnO nanotips were grown on amorphous fused silica substrates using metalorganic chemical vapor deposition. Structural, optical, and electrical properties of as-grown ZnO nanotips are investigated. Despite the amorphous nature of fused silica substrates, Ga-doped ZnO nanotips are found to be single crystalline and oriented along the c-axis. Photoluminescence (PL) spectra of Ga-doped ZnO nanotips are dominated by near-band-edge emission with negligible deep-level emission. The increase in PL intensity from Ga doping has been attributed to the increase of Ga donor-related impurity emission. Current–voltage characteristics of the ZnO nanotips are measured by conductive-tip atomic force microscopy, which shows the conductivity enhancement due to Ga doping.

Ga-doped ZnO single-crystal nanotips grown on fused silica by metalorganic chemical vapor deposition

A stacked-chip apparatus includes a package substrate and an interposer with a chip stack disposed with a standoff that matches the interposer. A package-on-package stacked-chip apparatus includes a top package disposed on the interposer.

Stacked-chip packages in package-on-package apparatus, methods of assembling same, and systems containing same

We demonstrate a wearable, flexible electrochemical biosensor for the combinatorial label-free detection of glucose in human sweat. The novel device comprises of stacked metal/metal-oxide (gold/zinc oxide) thin films within porous polyamide substrates for low-volume ultrasensitive impedance based detection of glucose and cortisol using non-faradaic electron-ionic charge transfer. In this work, we report the detection of glucose over a concentration range from 0.01–200 mg/dL spiked in synthetic and human sweat. Monoclonal antibodies specific to glucose oxidase were immobilized on thiolated ZnO sensing electrode surfaces resulting in the modulation of charge transfer within the electrical double layer (EDL). Non-Faradaic electrochemical impedance spectroscopy (EIS) was used to calibrate the sensor response with varying dose concentration through measurement of change in impedance. Reliable limit of detection (LOD) of 0.1 mg/dL in human sweat was demonstrated. Correlation of the sensor response with that of a commercial glucose meter TRUEresult™ Sensor (LOD of 20 mg/dL in blood) was found to be 0.9. Combinatorial detection of glucose and cortisol was demonstrated through frequency specific EIS measurements. Sensor variability was found to be within 15% of individual dynamic range for each molecule.

Sriram Muthukumar

Papers

A 280mV-to-1.2V wide-operating-range IA-32 processor in 32nm CMOS

Portable biosensor for monitoring cortisol in low-volume perspired human sweat

Ga-doped ZnO single-crystal nanotips grown on fused silica by metalorganic chemical vapor deposition

Stacked-chip packages in package-on-package apparatus, methods of assembling same, and systems containing same

Lancet-free and label-free diagnostics of glucose in sweat using Zinc Oxide based flexible bioelectronics