The effect of colour environments on visual tracking and visual strain during short-term simulation of three gravity states.

This study investigated the effects of nine colour environments on visual tracking accuracy and visual strain during normal sitting (SP), -12° head-down bed (HD) and 9.6° head-up tilt bed (HU). In a standard posture change laboratory study, fifty-four participants performed visual tracking tasks in nine colour environments while in the three postures. Visual strain was measured by means of a questionnaire. The results showed that in all colour environments, the -12° head-down bed rest posture significantly affected visual tracking accuracy and visual strain. During the three postures, the participants' visual tracking accuracy in the cyan environment was significantly higher than that in other colour environments, and their visual strain was the lowest. Overall, the study adds to our understanding of how environmental and postural factors impact on visual tracking and visual strain.

Elastic Knowledge Distillation by Learning From Recollection.

Model performance can be further improved with the extra guidance apart from the one-hot ground truth. To achieve it, recently proposed recollection-based methods utilize the valuable information contained in the past training history and derive a "recollection" from it to provide data-driven prior to guide the training. In this article, we focus on two fundamental aspects of this method, i.e., recollection construction and recollection utilization. Specifically, to meet the various demands of models with different capacities and at different training periods, we propose to construct a set of recollections with diverse distributions from the same training history. After that, all the recollections collaborate together to provide guidance, which is adaptive to different model capacities, as well as different training periods, according to our similarity-based elastic knowledge distillation (KD) algorithm. Without any external prior to guide the training, our method achieves a significant performance gain and outperforms the methods of the same category, even as well as KD with well-trained teacher. Extensive experiments and further analysis are conducted to demonstrate the effectiveness of our method.

Flexible terahertz metamaterial biosensor for label-free sensing of serum tumor marker modified on a non-metal area.

Terahertz (THz) metamaterials for rapid label-free sensing show application potential for the detection of cancer biomarkers. A novel flexible THz metamaterial biosensor based on a low refraction index parylene-C substrate is proposed. The biomarkers are modified on non-metal areas by a three-step modification method that simplifies the modification steps and improves the modified effectivity. Simulation results for non-metal modification illustrate that a bulk refractive index sensitivity of 325 GHz/RIU is achieved, which is larger than that obtained for the traditional metal modification (147 GHz/RIU). Meanwhile, several fluorescence experiments proved the uniform modification effect and selective adsorption capacity of the non-metal modification method. The concentration of the carcinoembryonic antigen (CEA) biomarkers for breast cancer patients tested using this THz biosensor is found to be consistent with results obtained from traditional clinical tests. The limit of detection reaches 2.97 ng/mL. These findings demonstrate that the flexible THz metamaterial biosensor can be extensively used for the rapid detection of cancer biomarkers in the future.

A Flexible Terahertz Metamaterial Biosensor for Cancer Cell Growth and Migration Detection.

Metamaterial biosensors have been extensively used to identify cell types and detect concentrations of tumor biomarkers. However, the methods for in situ and non-destruction measurement of cell migration, which plays a key role in tumor progression and metastasis, are highly desirable. Therefore, a flexible terahertz metamaterial biosensor based on parylene C substrate was proposed for label-free and non-destructive detection of breast cancer cell growth and migration. The maximum resonance peak frequency shift achieved 183.2 GHz when breast cancer cell MDA-MB-231 was cultured onto the surface of the metamaterial biosensor for 72 h. A designed polydimethylsiloxane (PDMS) barrier sheet was applied to detect the cell growth rate which was quantified as 14.9 µm/h. The experimental peak shift expressed a linear relationship with the covered area and a quadratic relationship with the distance, which was consistent with simulation results. Additionally, the cell migration indicated that the transform growth factor-ß (TGF-ß) promoted the cancer cell migration. The terahertz metamaterial biosensor shows great potential for the investigation of cell biology in the future.

In Situ Regeneration of Silicon Microring Biosensors Coated with Parylene C.

Optical biosensors support disease diagnostic applications, offering high accuracy and sensitivity due to label-free detection and their optical resonance enhancement. However, optical biosensors based on noble metal nanoparticles and precise micro-electromechanical system technology are costly, which is an obstacle for their applications. Here, we proposed a biosensor reuse method with nanoscale parylene C film, taking the silicon-on-insulator microring resonator biosensor as an example. Parylene C can efficiently adsorb antibody by one-step modification without any surface treatment, which simplifies the antibody modification process of sensors. Parylene C (20 nm thick) was successfully coated on the surface of the microring to modify anti-carcinoembryonic antigen (anti-CEA) and specifically detect CEA. After sensing, parylene C was successfully removed without damaging the sensing surface for the sensor reusing. The experimental results demonstrate that the sensing response did not change significantly after the sensor was reused more than five times, which verifies the repeatability and reliability of the reusable method by using parylene C. This framework can potentially reduce the cost of biosensors and promote their further applications.

Effect of 'hand and foot acupuncture with twelve needles' on hemiplegia patients with 'qi deficiency and blood stasis' syndrome in the convalescent stage of Ischaemic stroke: study protocol for a randomised controlled trial.

BACKGROUND: Hemiplegia is a common sequela after stroke, and acupuncture is one of the most common physical therapies used to treat hemiplegia during the recovery stage after ischaemic stroke. 'Hand and foot acupuncture with twelve needles' is an acupuncture treatment performed after stroke. The principal objective of this study is to assess the efficacy and safety of 'hand and foot acupuncture with twelve needles' for hemiplegia in the convalescent stage of ischaemic stroke. METHODS: This is the protocol for a randomised, controlled clinical trial with two groups: a 'hand and foot acupuncture with twelve needles' group and a routine acupuncture group. A total of 208 participants will be randomly assigned to two different groups in a 1:1 ratio and will undergo conventional rehabilitation. Limb function will be evaluated by the simplified Fugl-Meyer assessment scale, Barthel Index, modified Ashworth scale and National Institute of Health stroke scale. The participants will be evaluated at baseline (on the day of enrolment) and followed up at 2 weeks, 1 month, 2 months and 3 months after enrolment. DISCUSSION: The results of this study will provide evidence on the effectiveness of 'hand and foot acupuncture with twelve needles' in the treatment of limb dysfunction that can be used for future evaluations. TRIAL REGISTRATION: Chictr.org.cn ChiCTR1900021774 . Registered on 8 March 2019.

Route to Cost-Effective Fabrication of Wafer-Scale Nanostructure through Self-Priming Nanoimprint.

Nanoimprint technology is powerful for fabricating nanostructures in a large area. However, expensive equipment, high cost, and complex process conditions hinder the application of nano-imprinting technology. Therefore, double-layer self-priming nanoimprint technology was proposed to fabricate ordered metal nanostructures uniformly on 4-inch soft and hard substrates without the aid of expensive instruments. Different nanostructure (gratings, nanoholes and nanoparticles) and different materials (metal and MoS2) were patterned, which shows wide application of double-layer self-priming nanoimprint technology. Moreover, by a double-layer system, the width and the height of metal can be adjusted through the photoresist thickness and developing condition, which provide a programmable way to fabricate different nanostructures using a single mold. The double-layer self-priming nanoimprint method can be applied in poor condition without equipment and be programmable in nanostructure parameters using a single mold, which reduces the cost of instruments and molds.

Exploring performance of THz metamaterial biosensor based on flexible thin-film.

To extend the application of flexible metamaterial in the biosensor field, a metamaterial biosensor, which consisted of metal elliptical split-ring resonator array with a subwavelength structure based on flexible thin-film (parylene-c), was presented. The structure parameters (ring width, period ratio of structure, gap width, axial ratio) of the elliptical split-ring resonator and polarization direction of incident light were investigated as to how to affect the performances of the flexible metamaterial biosensor. Meanwhile, the permittivity (ε) of the tested sample on the surface of metamaterials biosensor also affected the shift of transmission spectra. The results showed that the sensitivity, quality (Q) factor, and figure of merit (FOM) of the flexible metamaterial biosensor could reach 243 GHz/RIU, 14.2, and 3.3, respectively. Moreover, the full-width-half-maximum (FWHM) was only 82 GHz. Therefore, these results provided an improved direction to design metamaterial biosensors with high Q-factor, low FOM, and high sensitivity, which could meet the need for sample detection in the terahertz regime.

Design and application of terahertz metamaterial sensor based on DSRRs in clinical quantitative detection of carcinoembryonic antigen.

The terahertz (THz) metamaterial biosensor has great potential for label-free and rapid specificity testing. Here, we designed two highly sensitive structures to detect the carcinoembryonic antigen (CEA) of the cancer biomarker in early stages. There was about 29 GHz (500 ng/ml) resonance shift for CEA with an insert grate metamaterial, which was consistent with simulation results. Moreover, the concentration of CEA was gained through the relationship between the cancer marker concentration and frequency shift (Δƒ). Our design and detection methods may provide a potential route for the early warning stages of cancer.

Smartphone Biosensor System with Multi-Testing Unit Based on Localized Surface Plasmon Resonance Integrated with Microfluidics Chip.

Detecting biomarkers is an efficient method to diagnose and monitor patients' stages. For more accurate diagnoses, continuously detecting and monitoring multiple biomarkers are needed. To achieve point-of-care testing (POCT) of multiple biomarkers, a smartphone biosensor system with the multi-testing-unit (SBSM) based on localized surface plasmon resonance (LSPR) integrated multi-channel microfluidics was presented. The SBSM could simultaneously record nine sensor units to achieve the detection of multiple biomarkers. Additional 72 sensor units were fabricated for further verification. Well-designed modularized attachments consist of a light source, lenses, a grating, a case, and a smartphone shell. The attachments can be well assembled and attached to a smartphone. The sensitivity of the SBSM was 161.0 nm/RIU, and the limit of detection (LoD) reached 4.2 U/mL for CA125 and 0.87 U/mL for CA15-3 through several clinical serum specimens testing on the SBSM. The testing results indicated that the SBSM was a useful tool for detecting multi-biomarkers. Comparing with the enzyme-linked immunosorbent assays (ELISA) results, the results from the SBSM were correlated and reliable. Meanwhile, the SBSM was convenient to operate without much professional skill. Therefore, the SBSM could become useful equipment for point-of-care testing due to its small size, multi-testing unit, usability, and customizable design.

Label-Free Exosome Detection Based on a Low-Cost Plasmonic Biosensor Array Integrated with Microfluidics.

Localized surface plasmon resonance-based plasmonic biosensors are interesting candidates for the design of portable optical biosensor platforms owing to their integration, miniaturization, multiparameter, real-time, and label-free detection characteristics. Plasmonic biosensor arrays that have been combined with microfluidics have been developed herein to detect exosomes label-free. Gold nano-ellipsoid arrays were fabricated with low-cost anodic aluminum oxide thin films that act as shadow masks for evaporation of Au. The nano-ellipsoid arrays were integrated with a microfluidic chip to achieve multiparameter detection. The anti-CD63 antibody that is specific to the exosome transmembrane protein CD63 is modified on the surface of the nano-ellipsoids. Exosome samples were injected into the biosensor platform at different concentrations and detected successfully. The detection limit was 1 ng/mL. The proposed plasmonic biosensor array can be universally applicable for the detection of other biomarkers by simply changing the antibody on the surface of the Au nano-ellipsoids. Moreover, this biosensor platform is envisaged to be potentially useful in the development of low-cost plasmonic-based biosensors for biomarker detection and for the investigation of exosomes for noninvasive disease diagnoses.

Exploring surface sensitivity of Rayleigh anomaly in metal/dielectric multilayer gratings.

Biosensors based on Rayleigh anomaly (RA) in metal gratings exhibit impressive bulk refractive index (RI) sensitivity and narrow linewidth. However, the electric field enhancement extends far away from surface of the gratings, which limits the application on biosensor where the RI changes are restricted at the sensor interface. To overcome this shortcoming, a novel grating composed of a 8-layer Au/Al2O3 stack was optimized by numerical simulation. The electric field is limited in several hundreds of nanometers from surface. The surface sensitivity increases 10 times than that of Au gratings at the detection depth of less than 400 nm. The surface index sensitivity can be improved 5 times under oblique incidence than that under normal incidence when the thickness of cover media is 20 nm.

Piezoelectric Microchip for Cell Lysis through Cell-Microparticle Collision within a Microdroplet Driven by Surface Acoustic Wave Oscillation.

Cell lysis is an important and crucial step for the detection of intracellular secrets. Usually, cell lysis is based on strong ultrasonic waves or toxic chemical regents, which require a large amount of cell suspension. To obtain high efficiency cell lysis for a small amount of sample, a mechanical cell lysis method based on a surface acoustic wave (SAW) microchip is proposed. The microchip simply consists of a piece of LiNbO3 crystal substrate, interdigitated transducers (IDTs) with 80 pairs of parallel electrodes and 3M Magic Tapes. The modulated input electrical signal is coupled into the substrate through IDTs, which produces an acoustic stream in the droplet on the surface of a substrate. When a biofluid droplet containing cells and microparticles is dropped on the surface of the microchip, the cells and microparticles are accelerated and collide with each other. The fluorescence staining results illustrate that the cell membrane is efficiently destroyed and that proteins as well as nucleic acids inside the cell are released. The experimental results show that this method has a high efficiency and low sample consumption. The potential application is the pretreatment of a small amount of tested sample in a hospital or biolab.