Type-I Core-Shell ZnSe/ZnS Quantum Dot-Based Resistive Switching for Implementing Algorithm.

Core-shell semiconductor quantum dots (QDs) are one of the biggest nanotechnology successes so far. In particular, type-I QDs with straddling band offset possess the ability to enhance the charge carriers capturing which is useful for memory application. Here, the type-I core-shell QD-based bipolar resistive switching (RS) memory with anomalous multiple SET and RESET processes was demonstrated. The synergy and competition between space charge limited current conduction (arising from charge trapping in potential well of type-I QDs) and electrochemical metallization (ECM, originating from redox reaction of Ag electrode) process were employed for modulating the RS behavior. Through utilizing stochastic RS mechanisms in QD-based devices, four situations of RS behaviors can be classified into three states in Markov chain for implementing the application of a true random number generator. Furthermore, a 6 × 6 cross-bar array was demonstrated to realize the generation of random letters with case distinction.

A Compact and Low Power RO PUF with High Resilience to the EM Side-Channel Attack and the SVM Modelling Attack of Wireless Sensor Networks.

Authentication is a crucial security service for the wireless sensor networks (WSNs) in versatile domains. The deployment of WSN devices in the untrusted open environment and the resource-constrained nature make the on-chip authentication an open challenge. The strong physical unclonable function (PUF) came in handy as light-weight authentication security primitive. In this paper, we present the first ring oscillator (RO) based strong physical unclonable function (PUF) with high resilience to both the electromagnetic (EM) side-channel attack and the support vector machine (SVM) modelling attack. By employing an RO based PUF architecture with the current starved inverter as the delay cell, the oscillation power is significantly reduced to minimize the emitted EM signal, leading to greatly enhanced immunity to the EM side-channel analysis attack. In addition, featuring superior reconfigurability due to the conspicuously simplified circuitries, the proposed implementation is capable of withstanding the SVM modelling attack by generating and comparing a large number of RO frequency pairs. The reported experimental results validate the prototype of a 9-stage RO PUF fabricated using standard 65 nm complementary-metal-oxide-semiconductor (CMOS) process. Operating at the supply voltage of 1.2 V and the frequency of 100 KHz, the fabricated RO PUF occupies a compact silicon area of 250 µ m 2 and consumes a power as low as 5.16 µ W per challenge-response pair (CRP). Furthermore, the uniqueness and the worst-case reliability are measured to be 50.17% and 98.30% for the working temperature range of -40∼120 ∘ C and the supply voltage variation of ±2%, respectively. Thus, the proposed PUF is applicable for the low power, low cost and secure WSN communications.

Gas Classification Using Deep Convolutional Neural Networks.

In this work, we propose a novel Deep Convolutional Neural Network (DCNN) tailored for gas classification. Inspired by the great success of DCNN in the field of computer vision, we designed a DCNN with up to 38 layers. In general, the proposed gas neural network, named GasNet, consists of: six convolutional blocks, each block consist of six layers; a pooling layer; and a fully-connected layer. Together, these various layers make up a powerful deep model for gas classification. Experimental results show that the proposed DCNN method is an effective technique for classifying electronic nose data. We also demonstrate that the DCNN method can provide higher classification accuracy than comparable Support Vector Machine (SVM) methods and Multiple Layer Perceptron (MLP).

Residual interpolation for division of focal plane polarization image sensors.

Division of focal plane (DoFP) polarization image sensors capture polarization properties of light at every imaging frame. However, these imaging sensors capture only partial polarization information, resulting in reduced spatial resolution output and a varying instantaneous field of overview (IFoV). Interpolation methods are used to reduce the drawbacks and recover the missing polarization information. In this paper, we propose residual interpolation as an alternative to normal interpolation for division of focal plane polarization image sensors, where the residual is the difference between an observed and a tentatively estimated pixel value. Our results validate that our proposed algorithm using residual interpolation can give state-of-the-art performance over several previously published interpolation methods, namely bilinear, bicubic, spline and gradient-based interpolation. Visual image evaluation as well as mean square error analysis is applied to test images. For an outdoor polarized image of a car, residual interpolation has less mean square error and better visual evaluation results.

Classification of Data from Electronic Nose Using Gradient Tree Boosting Algorithm.

In this paper, an approach that can fast classify the data from the electronic nose is presented. In this approach the gradient tree boosting algorithm is used to classify the gas data and the experiment results show that the proposed gradient tree boosting algorithm achieved high performance on this classification problem, outperforming other algorithms as comparison. In addition, electronic nose we used only requires a few seconds of data after the gas reaction begins. Therefore, the proposed approach can realize a fast recognition of gas, as it does not need to wait for the gas reaction to reach steady state.

Reverse bistable effect in ferroelectric liquid crystal devices with ultra-fast switching at low driving voltage.

In this Letter, reverse bistable effect with deep-sub-millisecond switching time is first reported in ferroelectric liquid crystal (FLC) devices using a homogeneous photo-alignment technique. It is indicated by our experimental results that both the anchoring energy and the dielectric property of the FLC's alignment layer is critical for the existence of the reverse bistable effect. In addition, with the derived criteria of the reverse bistable effect, we quantitatively analyze the switching dynamics of the reverse bistable FLC and the transition condition between the traditional bistability and our presented reverse bistability. Moreover, the fabricated FLC device exhibits an ultra-fast switching of ∼160 µs and a high contrast ratio of 1000:1, both of which were measured at a low driving voltage of 11 V. The featured deep-sub-millisecond switching time is really advantageous for our presented reverse bistable FLC devices, which enables a significant quality improvement of the existing optical devices, as well as a wide range of new applications in photonics and display areas.

Ultra-high sensitivity zinc oxide nanocombs for on-chip room temperature carbon monoxide sensing.

In this paper, we report an on-chip gas sensor based on novel zinc oxide (ZnO) nanocombs for carbon monoxide (CO) sensing. With ZnO gas sensing nanocombs fully integrated on a single silicon chip, the concept of low cost complementary-metal-oxide-semiconductor (CMOS) microsensor capable of on-chip gas sensing and processing is enabled. Compared with all previous implementations, the proposed ZnO nanocombs feature much larger effective sensing area and exhibit ultra-high sensitivity even at the room temperature. Specifically, at room temperature, we demonstrate peak sensitivities as high as 7.22 and 8.93 for CO concentrations of 250 ppm and 500 ppm, respectively. As a result, by operating the proposed ZnO-nanocomb-based gas sensor at the room temperature, the widely adopted power consuming heating components are completely removed. This leads to not only great power saving, but also full compatibility between the gas sensor and the on-chip circuitry in term of acceptable operating temperature. In addition, the reported fast response/recovery time of ~200 s/~50 s (250 ppm CO) makes it well suited to real-life applications.

Patterned dual-layer achromatic micro-quarter-wave-retarder array for active polarization imaging.

In this paper, we present a liquid-crystal-polymer (LCP)-based dual-layer micro-quarter-wave-retarder (MQWR) array for active polarization image sensors. The proposed MQWRs, for the first time, enable the extraction of the incident light's circularly polarized components in the whole visible regime, which correspond to the fourth parameter of Stokes vector. Compared with the previous implementations, our proposed MQWRs feature high achromaticity, making their applications no longer limited to monochromatic illumination. In addition, the presented thin structure exhibits an overall thickness of 2.43µm, leading to greatly alleviated optical cross-talk between adjacent photo-sensing pixels. Moreover, the reported superior optical performance (e.g. minor transmittance, extinction ratio) validates our optical design and optimization of the proposed MQWRs. Furthermore, the demonstrated simple fabrication recipe offers a cost-effective solution for the monolithic integration between the proposed MQWR array and the commercial solid-state image sensors, which makes the multi-spectral full Stokes polarization imaging system on a single chip feasible.

Two-step single slope/SAR ADC with error correction for CMOS image sensor.

Conventional two-step ADC for CMOS image sensor requires full resolution noise performance in the first stage single slope ADC, leading to high power consumption and large chip area. This paper presents an 11-bit two-step single slope/successive approximation register (SAR) ADC scheme for CMOS image sensor applications. The first stage single slope ADC generates a 3-bit data and 1 redundant bit. The redundant bit is combined with the following 8-bit SAR ADC output code using a proposed error correction algorithm. Instead of requiring full resolution noise performance, the first stage single slope circuit of the proposed ADC can tolerate up to 3.125% quantization noise. With the proposed error correction mechanism, the power consumption and chip area of the single slope ADC are significantly reduced. The prototype ADC is fabricated using 0.18 µ m CMOS technology. The chip area of the proposed ADC is 7 µ m × 500 µ m. The measurement results show that the energy efficiency figure-of-merit (FOM) of the proposed ADC core is only 125 pJ/sample under 1.4 V power supply and the chip area efficiency is 84 k µ m(2) · cycles/sample.

An analog gamma correction scheme for high dynamic range CMOS logarithmic image sensors.

In this paper, a novel analog gamma correction scheme with a logarithmic image sensor dedicated to minimize the quantization noise of the high dynamic applications is presented. The proposed implementation exploits a non-linear voltage-controlled-oscillator (VCO) based analog-to-digital converter (ADC) to perform the gamma correction during the analog-to-digital conversion. As a result, the quantization noise does not increase while the same high dynamic range of logarithmic image sensor is preserved. Moreover, by combining the gamma correction with the analog-to-digital conversion, the silicon area and overall power consumption can be greatly reduced. The proposed gamma correction scheme is validated by the reported simulation results and the experimental results measured for our designed test structure, which is fabricated with 0.35 µm standard complementary-metal-oxide-semiconductor (CMOS) process.

A High-Entropy Oxyhydroxide with a Graded Metal Network Structure for Efficient and Robust Alkaline Overall Water Splitting.

Designing high-entropy oxyhydroxides (HEOs) electrocatalysts with controlled nanostructures is vital for efficient and stable water-splitting electrocatalysts. Herein, a novel HEOs material (FeCoNiWCuOOH@Cu) containing five non-noble metal elements derived by electrodeposition on a 3D double-continuous porous Cu support is created. This support, prepared via the liquid metal dealloying method, offers a high specific surface area and rapid mass/charge transfer channels. The resulting high-entropy FeCoNiWCuOOH nanosheets provide a dense distribution of active sites. The heterostructure between Cu skeletons and FeCoNiWCuOOH nanosheets enhances mass transfer, electronic structure coupling, and overall structural stability, leading to excellent activities in the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and water splitting reaction. At 10 mA cm-2, the overpotentials for OER, HER, and water splitting in 1.0 m KOH solution are 200, 18, and 1.40 V, respectively, outperforming most current electrocatalysts. The catalytic performance remains stable even after operating at 300 mA cm-2 for 100, 100, and over 1000 h, correspondingly. This material has potential applications in integrated hydrogen energy systems. More importantly, density functional theory (DFT) calculations demonstrate the synergy of the five elements in enhancing water-splitting activity. This work offers valuable insights for designing industrial water electrolysis systems.

Celastrol Inhibits the Proliferation and Induces Apoptosis of Colorectal Cancer Cells via Downregulating NF-κB/COX-2 Signaling Pathways.

BACKGROUND: Colorectal cancer (CRC) is the third-ranked malignant tumor in the world that contributes to the death of a major population of the world. Celastrol, a bioactive natural product isolated from the medicinal plant Tripterygium wilfordii Hook F, has been proved to be an effective anti-tumor inhibitor for multiple tumors. OBJECTIVE: To reveal the therapeutic effect and underlying mechanisms of celastrol on CRC cells. METHODS: CCK-8 and clonogenic assay were used to analyze the cell proliferation in CRC cells. Flow cytometry analysis was conducted to assess the cell cycle and cell apoptosis. Wound-healing and cell invasion assay were used to evaluate the migrating and invasion capability of CRC cells. The potential antitumor mechanism of celastrol was investigated by qPCR, western blot, and confocal immunofluorescence analyses. RESULTS: Celastrol effectively inhibited CRC cell proliferation by activating caspase-dependent cell apoptosis and facilitating G1 cell cycle arrest in a dose-dependent manner, as well as cell migration and invasion by downregulating the MMP2 and MMP9. Mechanistic protein expression revealed that celastrol suppressed the expression of COX-2 by inhibiting the phosphorylation of NF-κB p65 and subsequently leading to cytoplasmic retention of p65 protein, thereby inhibiting its nuclear translocation and transcription activities. CONCLUSION: These findings indicate that celastrol is an effective inhibitor for CRC, regulating the NF-κB/COX-2 pathway, leading to the inhibition of cell proliferation characterized by cell cycle arrest and caspase-dependent apoptosis, providing a potential alternative therapeutic agent for CRC patients.

A novel room-temperature formaldehyde gas sensor based on walnut-like WO3 modification on Ni-graphene composites.

Ternary composite with great modulation of electron transfers has attracted a lot of attention from the field of high-performance room-temperature (RT) gas sensing. Herein, walnut-like WO3-Ni-graphene ternary composites were successfully synthesized by the hydrothermal method for formaldehyde (HCHO) sensing at RT. The structural and morphological analyses were carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). SEM and TEM studies confirmed that walnut-like WO3 nanostructures with an average size of 53 ± 23 nm were functionalized. The Raman and XPS results revealed that, due to the deformation of the O-W-O lattice, surface oxygen vacancies Ov and surface-adsorbed oxygen species Oc were present. The gas-sensing measurement shows that the response of the WO3-Ni-Gr composite (86.8%) was higher than that of the Ni-Gr composite (22.7%) for 500 ppm HCHO at RT. Gas-sensing enhancement can be attributed to a p-n heterojunction formation between WO3 and Ni-Gr, Oc, spill-over effect of Ni decoration, and a special walnut-like structure. Moreover, long term stability (%R = 61.41 ± 1.66) for 30 days and high selectivity in the presence of other gases against HCHO suggested that the proposed sensor could be an ideal candidate for future commercial HCHO-sensing in a real environment.

High-resolution thin "guest-host" micropolarizer arrays for visible imaging polarimetry.

We report a micropolarizer array technology exploiting "guest-host" interactions in liquid crystals for visible imaging polarimetry. We demonstrate high resolution thin micropolarizer arrays with a 5 µm×5 µm pixel pitch and a thickness of 0.95 µm. With the "host" nematic liquid crystal molecules photo-aligned by sulfonic azo-dye SD1, we report averaged major principal transmittance, polarization efficiency and order parameter of 80.3%, 0.863 and 0.848, respectively across the 400 nm-700 nm visible spectrum range. The proposed fabrication technology completely removes the need for any selective etching during the fabrication/integration process of the micropolarizer array. Fully CMOS compatible, it is simple and cost-effective, requiring only spin-coating followed by a single ultraviolet-exposure through a "photoalignment master". This makes it well suited to low cost polarization imaging applications.

[Comparative clinical study of wavefront-guided laser in situ keratomileusis with versus without iris recognition for myopia or myopic astigmatism].

OBJECTIVE: To explore the postoperative visual acuity results of wavefront-guided LASIK with iris recognition for myopia or myopic astigmatism and the changes of higher-order aberrations and contrast sensitivity function (CSF). METHODS: Series of prospective case studies, 158 eyes (85 cases) of myopia or myopic astigmatism were divided into two groups: one group underwent wavefront-guided LASIK with iris recognition (iris recognition group); another group underwent wavefront-guided LASIK treatment without iris recognition through the limbus maring point (non-iris recognition group). To comparative analyze the postoperative visual acuity, residual refraction, the RMS of higher-order aberrations and CSF of two groups. RESULTS: There was no statistical significance difference between two groups of the average uncorrected visual acuity (t = 0.039, 0.058, 0.898; P = 0.844, 0.810, 0.343), best corrected visual acuity (t = 0.320, 0.440, 1.515; P = 0.572, 0.507, 0.218), and residual refraction [spherical equivalent (t = 0.027, 0.215, 0.238; P = 0.869, 0.643, 0.626), spherical (t = 0.145, 0.117, 0.038; P = 0.704, 0.732, 0.845) and cylinder (t = 1.676, 1.936, 0.334; P = 0.195, 0.164, 0.563)] at postoperative 10 days, 1 month and 3 month. The security index of iris recognition group at postoperative 3 month was 1.06 and non-iris recognition group was 1.03; the efficacy index of iris recognition group is 1.01 and non-iris recognition group was 1.00. Postoperative 3 month iris recognition group 93.83% eyes and non-iris recognition group of 90.91% eyes spherical equivalent within ± 0.50 D (χ(2) = 0.479, P = 0.489), iris recognition group of 98.77% eyes and non-iris recognition group of 97.40% eyes spherical equivalent within ± 1.00 D (Fisher test, P = 0.613). There was no significance difference between the two groups of security, efficacy and predictability. Non-iris recognition group postoperative 1 month and postoperative 3 months 3-order order aberrations root mean square value (RMS) higher than the iris recognition group increased (t = 3.414, -2.870; P = 0.027, 0.045), in particular of coma; the general higher-order aberrations (t = 0.386, 1.132; P = 0.719, 0.321), 4-order aberrations (t = 0.808, 2.720; P = 0.464, 0.063), and 5-order aberrations (t = 0.148, -1.717; P = 0.890, 0.161) show no statistically significant difference. Three months after surgery, two groups have recovered at all spatial frequencies of CSF, iris recognition group at 3.0 c/d (t = 3.209, P = 0.002) and 6.0 c/d (t = 2.997, P = 0.004) spatial frequencies of CSF under mesopic condition was better than non-iris recognition group, glare contrast sensitivity function (GCSF) for 3.0 c/d (t = 3.423, P = 0.001) and 6.0 c/d (t = 6.986, P = 0.000) spatial frequencies under mesopic condition and 1.5 c/d (t = 9.839, P = 0.000) and 3.0 c/d (t = 7.367, P = 0.000) spatial frequencies under photopic condition in iris recognition group were better than non-iris recognition group, there were no significant difference between two groups at the other spatial frequencies. CONCLUSIONS: Wavefront-guided LASIK with or without iris recognition both acquired better postoperative visual acuity, but in comparison with without iris recognition, wavefront-guided LASIK with iris recognition is efficient to reduce coma and enhance contrast sensitivity of postoperative.

A p-n Heterojunction Based Pd/PdO@ZnO Organic Frameworks for High-Sensitivity Room-Temperature Formaldehyde Gas Sensor.

As formaldehyde is an extremely toxic volatile organic pollutant, a highly sensitive and selective gas sensor for low-concentration formaldehyde monitoring is of great importance. Herein, metal-organic framework (MOF) derived Pd/PdO@ZnO porous nanostructures were synthesized through hydrothermal method followed by calcination processes. Specifically, porous Pd/PdO@ZnO nanomaterials with large surfaces were synthesized using MOFs as sacrificial templates. During the calcination procedure, an optimized temperature of 500°C was used to form a stable structure. More importantly, intensive PdO@ZnO inside the material and composite interface provides lots of p-n heterojunction to efficiently manipulate room temperature sensing performance. As the height of the energy barrier at the junction of PdO@ZnO exponentially influences the sensor resistance, the Pd/PdO@ZnO nanomaterials exhibit high sensitivity (38.57% for 100 ppm) at room temperature for 1-ppm formaldehyde with satisfactory selectivity towards (ammonia, acetone, methanol, and IPA). Besides, due to the catalytic effect of Pd and PdO, the adsorption and desorption of the gas molecules are accelerated, and the response and recovery time is as small as 256 and 264 s, respectively. Therefore, this MOF-driven strategy can prepare metal oxide composites with high surface area, well-defined morphology, and satisfactory room-temperature formaldehyde gas sensing performance for indoor air quality control.

Liquid-crystal micropolarimeter array for full Stokes polarization imaging in visible spectrum.

In this paper, we describe the design, modeling, fabrication, and optical characterization of the first micropolarimeter array enabling full Stokes polarization imaging in visible spectrum. The proposed micropolarimeter is fabricated by patterning a liquid-crystal (LC) layer on top of a visible-regime metal-wire-grid polarizer (MWGP) using ultraviolet sensitive sulfonic-dye-1 as the LC photoalignment material. This arrangement enables the formation of either micrometer-scale LC polarization rotators, neutral density filters or quarter wavelength retarders. These elements are in turn exploited to acquire all components of the Stokes vector, which describes all possible polarization states of light. Reported major principal transmittance of 75% and extinction ratio of 1100 demonstrate that the MWGP's superior optical characteristics are retained. The proposed liquidcrystal micropolarimeter array can be integrated on top of a complementary metal-oxide-semiconductor (CMOS) image sensor for real-time full Stokes polarization imaging.

Micheliolide suppresses the viability, migration and invasion of U251MG cells via the NF-κB signaling pathway.

Micheliolide (MCL), a sesquiterpene lactone isolated from Michelia compressa and Michelia champaca, has been used previously to inhibit the NF-κB signaling pathway. MCL has exerted various therapeutic effects in numerous types of disease, such as inflammatory and cancer. However, to the best of our knowledge, its underlying anticancer mechanism remains to be understood. The present study aimed to investigate the effects of MCL on human glioma U251MG cells and to determine the potential anticancer mechanism of action of MCL. From Cell Counting Kit-8, colony formation assay, apoptosis assay and Confocal immunofluorescence imaging analysis, the results revealed that MCL significantly inhibited cell viability in vitro and induced cell apoptosis via activation of the cytochrome c/caspase-dependent apoptotic pathway. In addition, MCL also suppressed cell invasion and metastasis via the wound healing and Transwell invasion assays. Furthermore, western blot and reverse transcription PCR analyses demonstrated that MCL significantly downregulated cyclooxygenase-2 (COX-2) expression levels, which may have partially occurred through the inactivation of the NF-κB signaling pathway. In conclusion, the results of the present study indicated that MCL may inhibit glioma carcinoma growth by downregulating the NF-κB/COX-2 signaling pathway, which suggested that MCL may be a novel and alternative antitumor agent for the treatment of human glioma carcinoma.

High-resolution photoaligned liquid-crystal micropolarizer array for polarization imaging in visible spectrum.

We report a superior high-resolution micropolarizer array fabrication technology that combines a linear polarizer with a micropatterned liquid-crystal (LC) cell. A 2 microm pitch is achieved by using UV light to define the orientation of the micropolarizer elements. Reported experimental results validate the concept of high-performance photoaligned LC micropolarizer arrays with major principal transmittance of approximately 80% and extinction ratio as high as approximately 3200(35 dB).

Sex Determination According to the Lengths of Hand Bones in Rhesus Macaques (Macaca Mulatta).

Measurement of hand bone length has been used for sex determination in humans and nonhuman primates (McFadden and Bracht: Early Hum Dev 85 (2009) 117-124; El-Morsi and Al-Hawary: J Forensic Leg Med 20 (2013) 6-13). The aim of this study was to determine the sex of rhesus macaques (Macaca mulatta) on the basis of the lengths of corresponding rows of metacarpals and phalanges in a macaque population by means of developing discriminant functions. Measurements on direct dry bones only included lengths for 19 bones of the left hand in 39 macaques (consisting of 13 adult males and 26 adult females). The results revealed that the mean values of males were significantly greater than those of females for all of the metacarpals and phalanges. The results were obtained in 84.4% of accuracy from distal phalanges, 93.8% from middle phalanges, and 96.9% from both metacarpals and proximal phalanges, respectively. There was a remarkable difference in the magnitude of sex dimorphism in lengths of each section of the hand bones between the population of macaques and humans. This difference may be attributable to the interaction between genetic factors and various environmental factors. As sex differences of hand bones are population-specific (Lazenby: Am J phys Anthropol 118 (2002) 378-384; Lu, Huo, Shi, Peng, Dang, Jiao, Zhu, Zhong, and Chen: Acta Aantomica Sinica 39 (2008) 267-271; Eshak, Ahmed, and Gawad: J Forensic Leg Med 18 (2011) 246-252), the discriminant equations for all of the metacarpals and phalanges are applicable to the population of Macaca mulatta from the Taihang Mountain. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1741-1746, 2017. © 2017 Wiley Periodicals, Inc.