Artificial Intelligence-Enhanced Waveguide "Photonic Nose"- Augmented Sensing Platform for VOC Gases in Mid-Infrared.

On-chip nanophotonic waveguide sensor is a promising solution for miniaturization and label-free detection of gas mixtures utilizing the absorption fingerprints in the mid-infrared (MIR) region. However, the quantitative detection and analysis of organic gas mixtures is still challenging and less reported due to the overlapping of the absorption spectrum. Here,an Artificial-Intelligence (AI) assisted waveguide "Photonic nose" is presented as an augmented sensing platform for gas mixture analysis in MIR. With the subwavelength grating cladding supported waveguide design and the help of machine learning algorithms, the MIR absorption spectrum of the binary organic gas mixture is distinguished from arbitrary mixing ratio and decomposed to the single-component spectra for concentration prediction. As a result, the classification of 93.57% for 19 mixing ratios is realized. In addition, the gas mixture spectrum decomposition and concentration prediction show an average root-mean-square error of 2.44 vol%. The work proves the potential for broader sensing and analytical capabilities of the MIR waveguide platform for multiple organic gas components toward MIR on-chip spectroscopy.

Quantitative risk assessments of Salmonella spp. in domestic pork in China.

Pork is one of the most commonly consumed meats, and its safety has always been a concern. Recently, safety incidents caused by chemical or biological contamination such as drug residues, heavy metals, and pathogenic microorganisms in pork have been reported, and the safety of pork is a cause for concern. Salmonella spp. is one of the important foodborne pathogens that threaten human health. Pork is a high-risk vector food for Salmonella spp. infection. The assessment of the safety risk of Salmonella spp. in pork is conducive to the prevention of related foodborne diseases. In this paper, risk assessment models for Salmonella spp. in meat were developed. The quantitative risk assessment model for Salmonella spp. based on the pork supply chain showed that the annual number of cases of salmonellosis due to pork consumption in China is approximately 27 per 10,000 males and 24 per 10,000 females. Sensitivity analysis showed that the main factors affecting the risk of Salmonella spp. in pork were the display temperature, display time, and Salmonella spp. contamination concentration in pork at the sale.

Review of Miniaturized Computational Spectrometers.

Spectrometers are key instruments in diverse fields, notably in medical and biosensing applications. Recent advancements in nanophotonics and computational techniques have contributed to new spectrometer designs characterized by miniaturization and enhanced performance. This paper presents a comprehensive review of miniaturized computational spectrometers (MCS). We examine major MCS designs based on waveguides, random structures, nanowires, photonic crystals, and more. Additionally, we delve into computational methodologies that facilitate their operation, including compressive sensing and deep learning. We also compare various structural models and highlight their unique features. This review also emphasizes the growing applications of MCS in biosensing and consumer electronics and provides a thoughtful perspective on their future potential. Lastly, we discuss potential avenues for future research and applications.

High-throughput doubly-encoded single-pixel spectrometer with an extended aperture.

Infrared devices are increasingly used in industrial, medical, and environmental monitoring applications. Cost-effectiveness, robustness, and portability are characteristics that are highly sought after and they can be enabled by a dispersive spectrometer carrying a single-pixel detector. In this paper, we demonstrate a novel, high-throughput dispersive spectrometer that has its spectral resolution decoupled from its throughput. The proposed spectrometer implements a two-stage Hadamard transform encoding process that allows significantly more light into the system to enhance its signal-to-noise ratio. As a single-pixel detector is used to collect the spectral information, the proposed system can be easily implemented in other desired wavelengths. Furthermore, we develop a method to remove the need for uniform illumination at the entrance aperture by taking into consideration its spatial information during the reconstruction process, thereby increasing the ease of the design of devices required for in situ measurement.

TDI-like multi-slit hyperspectral imaging for enhanced throughput via the Kalman filter.

The time-delay integration (TDI) technique is increasingly used to improve the signal-to-noise ratio (SNR) of remote sensing and imaging by exposing the scene multiple times. Inspired by the principle of TDI, we propose a TDI-like pushbroom multi-slit hyperspectral imaging (MSHSI) approach. In our system, multiple slits are used to significantly improve the throughput of the system, thereby enhancing the sensitivity and SNR through multiple exposures of the same scene during pushbroom scan. Meanwhile, a linear dynamic model for the pushbroom MSHSI is established, where the Kalman filter (KF) is employed to reconstruct the time-varying overlapped spectral images on a single conventional image sensor. Further, we designed and fabricated a customized optical system that can operate in both multi-slit and single slit modes to experimentally verify the feasibility of the proposed method. Experimental results indicate that the developed system improved SNR by a factor of about 7 compared to that of the single slit mode, while demonstrating excellent resolution in both spatial and spectral dimensions.

Silicon Photonic Phase Shifters and Their Applications: A Review.

With the development of silicon photonics, dense photonic integrated circuits play a significant role in applications such as light detection and ranging systems, photonic computing accelerators, miniaturized spectrometers, and so on. Recently, extensive research work has been carried out on the phase shifter, which acts as the fundamental building block in the photonic integrated circuit. In this review, we overview different types of silicon photonic phase shifters, including micro-electro-mechanical systems (MEMS), thermo-optics, and free-carrier depletion types, highlighting the MEMS-based ones. The major working principles of these phase shifters are introduced and analyzed. Additionally, the related works are summarized and compared. Moreover, some emerging applications utilizing phase shifters are introduced, such as neuromorphic computing systems, photonic accelerators, multi-purpose processing cores, etc. Finally, a discussion on each kind of phase shifter is given based on the figures of merit.

Does Servant Leadership Stimulate Work Engagement? The Moderating Role of Trust in the Leader.

A positive leadership style can promote work engagement. Using social exchange theory, this study examines the impact of employee leadership styles on work engagement. In addition, the link also considered the mitigating role of trust in leaders. Preliminary data were collected from the educational and non-educational staff of the Business Management Sciences and Education Department at different universities. We collected responses from 242 employees from selected universities using the purposive sampling technique. We tested the proposed hypothesis using linear regression. Research has shown that there is a positive link between employee leadership and work engagement. When trust in leaders as facilitators was introduced, the relationship between leadership and work engagement was relaxed to increase trust in leaders. Practical and theoretical contributions to the study were provided with recommendations for further study.

Risk Assessment of Veterinary Drug Residues in Pork on the Market in the People's Republic of China.

ABSTRACT: Veterinary drugs, including antibiotics, antiparasitics, and growth promoters, are widely used in animal husbandry. Veterinary drug residues are key issues of food safety because they arouse public concern and can seriously endanger the health of consumers. To assess the risk of veterinary drug residues in pork sold in the People's Republic of China, the potential veterinary drug residue risks in imported and domestic pork were analyzed based on regulatory differences and veterinary drug residue safety incidents. For imported pork, a risk assessment model was established based on the differences in veterinary drug residue limits for the People's Republic of China, Brazil, the United States, Australia, Thailand, and Russia combined with comprehensive evaluation methods. The potential risk of veterinary drug residues in U.S. pork was the highest, and that in Brazilian pork was the lowest. For domestic pork, the distribution and aggregation of veterinary drug residue safety incidents in the People's Republic of China was analyzed from 2015 to 2019 with a geographic information system. This study provides new insights into the safety of pork on the Chinese market and a scientific basis for formulating targeted supervision and early warning strategies.

Mid-infrared silicon photonic phase shifter based on microelectromechanical system.

Mid-infrared (MIR) photonic integrated circuits have generated considerable interest, owing to their potential applications, such as thermal imaging and biochemical sensing. A challenging area in the field is the development of reconfigurable approaches for the enhancement of on-chip functions, where a phase shifter plays an important role. Here, we demonstrate a MIR microelectromechanical system (MEMS) phase shifter by utilizing an asymmetric slot waveguide with subwavelength grating (SWG) claddings. The MEMS-enabled device can be easily integrated into a fully suspended waveguide with SWG cladding, built on a silicon-on-insulator (SOI) platform. Through engineering of the SWG design, the device achieves a maximum phase shift of 6π, with an insertion loss of 4 dB and a half-wave-voltage-length product (VπLπ) of 2.6 V·cm. Moreover, the time response of the device is measured as 13 µs (rise time) and 5 µs (fall time).

Design and fabrication of composite polygonal Fresnel lenses.

High fill factor for Fresnel lens arrays has been achieved with the aid of polygonal lenses. This has been done for both circular trimmed lenses and full polygonal lenses, both of which present some optical drawbacks. The composite polygonal Fresnel lens (CPFL) avoids these issues with its unique design - a radial symmetric Fresnel center filling into a polygon, avoiding any intersecting facets within the lens by introducing fillets. To manufacture the CPFL, diamond shaping is applied to not only meet the strict standards required for optical fabrication but also maneuver around the curvilinear features that cannot be fabricated using conventional turning techniques. As such, direct diamond shaping (DDS) was employed to generate an array of CPFLs on a PMMA substrate. Optical simulation was used to validate the performance of the CPFL before production of the lens array, followed by testing of the fabricated lenses, showing less overall noise with better focus compared to conventional polygonal lenses.

Cascaded, self-calibrated, single-pixel mid-infrared Hadamard transform spectrometer.

In this paper, a single-pixel mid-infrared (mid-IR) Hadamard transform spectrometer is developed. The spectrometer's design, fabrication and experimental results are discussed. The single-pixel mid-IR Hadamard transform spectrometer has dual cascaded encoding regions, 2875 nm to 3500 nm and 3500 nm to 4077 nm, to reduce the travel range required by the moving mask. The encoded wavelength band is determined by the bandpass filter used. A collection optics consisting of a reverse spectrometer is used to collect the encoded signal onto a single-pixel detector with a small sensing area. A 635 nm laser is used as a reference within the spectrometer to calibrate the recovered spectrum with accurate positioning. Our experiments demonstrate that mid-IR spectrums can be accurately recovered in the designed wavelength range. The proposed spectrometer, with dimensions of 200 mm × 200 mm × 84 mm and a weight of 1.8 kg, can be made portable and at low cost, suitable for IR spectroscopy in the field.

Suspended Silicon Waveguide with Sub-Wavelength Grating Cladding for Optical MEMS in Mid-Infrared.

Mid-infrared (MIR) photonics are generating considerable interest because of the potential applications in spectroscopic sensing, thermal imaging, and remote sensing. Silicon photonics is believed to be a promising solution to realize MIR photonic integrated circuits (PICs). The past decade has seen a huge growth in MIR PIC building blocks. However, there is still a need for the development of MIR reconfigurable photonics to enable powerful on-chip optical systems and new functionalities. In this paper, we present an MIR (3.7~4.1 µm wavelength range) MEMS reconfiguration approach using the suspended silicon waveguide platform on the silicon-on-insulator. With the sub-wavelength grating claddings, the photonic waveguide can be well integrated with the MEMS actuator, thus offering low-loss, energy-efficient, and effective reconfiguration. We present a simulation study on the waveguide design and depict the MEMS-integration approach. Moreover, we experimentally report the suspended waveguide with propagation loss (-2.9 dB/cm) and bending loss (-0.076 dB each). The suspended waveguide coupler is experimentally investigated. In addition, we validate the proposed optical MEMS approach using a reconfigurable ring resonator design. In conclusion, we experimentally demonstrate the proposed waveguide platform's capability for MIR MEMS-reconfigurable photonics, which empowers the MIR on-chip optical systems for various applications.

Bi-layered composite gratings with high diffraction efficiency enabled by near-field coupling.

In this paper, we present a design method for bi-layered composite gratings to achieve high diffraction efficiency. These composite gratings feature strong near-field coupling between their constituent dielectric subwavelength gratings, thus enabling high-efficiency first-order diffraction in the far-field. An intuitive explanation based on a wavevector matching condition for such high diffraction efficiency composite gratings is provided. According to theoretical analysis, a design strategy for the proposed composite gratings is developed and verified by numerical simulations with gratings working in both TE and TM modes. The proposed strategy could open door to develop bi-layered composite gratings for manipulating diffracted waves with high efficiency, thus may potentially enable new applications in photonic systems.

Multifunctional mid-infrared photonic switch using a MEMS-based tunable waveguide coupler.

We demonstrate a multifunctional photonic switch on silicon-on-insulator platform operating at the mid-infrared wavelength range (3.85-4.05 µm) using suspended waveguides with sub-wavelength cladding and a micro-electro-mechanical systems (MEMS) tunable waveguide coupler. Leveraging the flip-chip bonding technology, a top wafer acting as the electrode is assembled above the silicon-on-insular wafer to enable the electrostatic actuation. Experimental characterizations for the functions of the proposed device include (1) an optical attenuator with 25 dB depth using DC voltage actuation, (2) a 1×2 optical switch with response time of 8.9 µs and -3dB bandwidth up to 127 kHz using AC voltage actuation, and (3) an on-chip integrated light chopper with the comparable performance of a commercial rotating disc light chopper.

Wearable Triboelectric-Human-Machine Interface (THMI) Using Robust Nanophotonic Readout.

With the rapid advances in wearable electronics and photonics, self-sustainable wearable systems are desired to increase service life and reduce maintenance frequency. Triboelectric technology stands out as a promising versatile technology due to its flexibility, self-sustainability, broad material availability, low cost, and good scalability. Various triboelectric-human-machine interfaces (THMIs) have been developed including interactive gloves, eye blinking/body motion-triggered interfaces, voice/breath monitors, and self-induced wireless interfaces. Nonetheless, THMIs conventionally use electrical readout and produce pulse-like signals due to the transient charge flows, leading to unstable and lossy transfer of interaction information. To address this issue, we propose a strategy by equipping THMIs with robust nanophotonic aluminum nitride (AlN) modulators for readout. The electrically capacitive nature of AlN modulators enables THMIs to work in the open-circuit condition with negligible charge flows. Meanwhile, the interaction information is transduced from THMIs' voltage to AlN modulators' optical output via the electro-optic Pockels effect. Thanks to the negligible charge flow and the high-speed optical information carrier, stable, information-lossless, and real-time THMIs are achieved. Leveraging the design flexibility of THMIs and nanophotonic readout circuits, various linear sensitivities independent of force speeds are achieved in different interaction force ranges. Toward practical applications, we develop a smart glove to realize continuous real-time robotics control and virtual/augmented reality interaction. Our work demonstrates a generic approach for developing self-sustainable HMIs with stable, information-lossless, and real-time features for wearable systems.

Single-Pixel MEMS Imaging Systems.

Single-pixel imaging technology is an attractive technology considering the increasing demand of imagers that can operate in wavelengths where traditional cameras have limited efficiency. Meanwhile, the miniaturization of imaging systems is also desired to build affordable and portable devices for field applications. Therefore, single-pixel imaging systems based on microelectromechanical systems (MEMS) is an effective solution to develop truly miniaturized imagers, owing to their ability to integrate multiple functionalities within a small device. MEMS-based single-pixel imaging systems have mainly been explored in two research directions, namely the encoding-based approach and the scanning-based approach. The scanning method utilizes a variety of MEMS scanners to scan the target scenery and has potential applications in the biological imaging field. The encoding-based system typically employs MEMS modulators and a single-pixel detector to encode the light intensities of the scenery, and the images are constructed by harvesting the power of computational technology. This has the capability to capture non-visible images and 3D images. Thus, this review discusses the two approaches in detail, and their applications are also reviewed to evaluate the efficiency and advantages in various fields.

Prediction for Global Peste des Petits Ruminants Outbreaks Based on a Combination of Random Forest Algorithms and Meteorological Data.

Peste des Petits Ruminants (PPR) is an acute and highly contagious transboundary disease caused by the PPR virus (PPRV). The virus infects goats, sheep and some wild relatives of small domestic ruminants, such as antelopes. PPR is listed by the World Organization for Animal Health as an animal disease that must be reported promptly. In this paper, PPR outbreak data combined with WorldClim database meteorological data were used to build a PPR prediction model. Using feature selection methods, eight sets of features were selected: bio3, bio10, bio15, bio18, prec7, prec8, prec12, and alt for modeling. Then different machine learning algorithms were used to build models, among which the random forest (RF) algorithm was found to have the best modeling effect. The ACC value of prediction accuracy for the model on the training set can reach 99.10%, while the ACC on the test sets was 99.10%. Therefore, RF algorithms and eight features were finally selected to build the model in order to build the online prediction system. In addition, we adopt single-factor modeling and correlation analysis of modeling variables to explore the impact of each variable on modeling results. It was found that bio18 (the warmest quarterly precipitation), prec7 (the precipitation in July), and prec8 (the precipitation in August) contributed significantly to the model, and the outbreak of the epidemic may have an important relationship with precipitation. Eventually, we used the final qualitative prediction model to establish a global online prediction system for the PPR epidemic.

Dairy Safety Prediction Based on Machine Learning Combined with Chemicals.

BACKGROUND: Dairy safety has caused widespread concern in society. Unsafe dairy products have threatened people's health and lives. In order to improve the safety of dairy products and effectively prevent the occurrence of dairy insecurity, countries have established different prevention and control measures and safety warnings. OBJECTIVE: The purpose of this study is to establish a dairy safety prediction model based on machine learning to determine whether the dairy products are qualified. METHODS: The 34 common items in the dairy sampling inspection were used as features in this study. Feature selection was performed on the data to obtain a better subset of features, and different algorithms were applied to construct the classification model. RESULTS: The results show that the prediction model constructed by using a subset of features including "total plate", "water" and "nitrate" is superior. The SN, SP and ACC of the model were 62.50%, 91.67% and 72.22%, respectively. It was found that the accuracy of the model established by the integrated algorithm is higher than that by the non-integrated algorithm. CONCLUSION: This study provides a new method for assessing dairy safety. It helps to improve the quality of dairy products, ensure the safety of dairy products, and reduce the risk of dairy safety.

Ultra-small photonic crystal (PhC)-based test tool for gas permeability of polymers.

We present an ultra-small photonic crystal-based test tool for gas permeability of polymers. It features a fully-etched photonic crystal (PhC) structure occupying an area of 20 µm × 800 µm on silicon-on-insulator wafer. The light-matter interaction in the PhC cavity with deformed Polydimethylsiloxane (PDMS) under pressure difference was investigated with finite element method and finite-difference time-domain method numerically. Next, three PDMS membranes of different mixing ratios were utilized for the characterization of gas permeation flux. The feasibility and effectiveness of the proposed working mechanism are verified through clearly distinguishing the gas permeability of these three testing samples. Compared with conventional test tools, this proposed test tool has fast response while it consumes less testing gas volume in a testing system with reduced footprint. Potentially, it can be integrated into lab-on-a-chip devices to measure gas permeation in nano scale.

A Study of the Mechanism of Binding between Neratinib and MAD2L1 Based on Molecular Simulation and Multi-spectroscopy Methods.

BACKGROUND: Nilatinib is an irreversible tyrosine kinase inhibitor, which is used in the treatment of some kinds of cancer. To study the interaction between Neratinib and MAD2L1, a potential tumor target, is of guiding significance for enriching the medicinal value of Neratinib. METHOD: The binding mechanism between Mitotic arrest deficient 2-like protein 1 (MAD2L1) and Neratinib under simulative physiological conditions was investigated by molecule simulation and multi-spectroscopy approaches. RESULTS: Molecular docking showed the most possible binding mode of Neratinib-MAD2L1 and the potential binding sites and interaction forces of the interaction between MAD2L1 and Neratinib. Fluorescence spectroscopy experiments manifested that Neratinib could interact with MAD2L1 and form a complex by hydrogen bond and van der Waals interaction. These results were consistent with the conclusions obtained from molecular docking. In addition, according to Synchronous fluorescence and three-dimensional fluorescence results, Neratinib might lead to the conformational change of MAD2L1, which may affect the biological functions of MAD2L1. CONCLUSION: This study indicated that Neratinib could interact with MAD2L1 and lead to the conformational change of MAD2L1. These works provide helpful insights for the further study of biological function of MAD2L1 and novel pharmacological utility of Neratinib.