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Single-Molecule Imaging of mRNA Localization and Regulation during the Integrated Stress Response
摘要： Biological phase transitions form membrane-less organelles that generate distinct cellular environments. How molecules are partitioned between these compartments and the surrounding cellular space and the functional consequence of this localization is not well understood. Here, we report the localization of mRNA to stress granules (SGs) and processing bodies (PBs) and its effect on translation and degradation during the integrated stress response. Using single mRNA imaging in living human cells, we find that the interactions of mRNAs with SGs and PBs have different dynamics, very few mRNAs directly move between SGs and PBs, and that specific RNA-binding proteins can anchor mRNAs within these compartments. During recovery from stress, we show that mRNAs that were within SGs and PBs are translated and degraded at similar rates as their cytosolic counterparts. Our work provides a framework for using single-molecule measurements to directly investigate the molecular mechanisms of phase-separated compartments within their cellular environment.
关键词： P-bodies,integrated stress response,degradation,stress granules,LARP1,mRNA localization,single-molecule imaging,translation
更新于2025-09-23 15:22:29
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Controlling the shape of 3D microstructures by temperature and light
摘要： Stimuli-responsive microstructures are critical to create adaptable systems in soft robotics and biosciences. For such applications, the materials must be compatible with aqueous environments and enable the manufacturing of three-dimensional structures. Poly(N-isopropylacrylamide) (pNIPAM) is a well-established polymer, exhibiting a substantial response to changes in temperature close to its lower critical solution temperature. To create complex actuation patterns, materials that react differently with respect to a stimulus are required. Here, we introduce functional three-dimensional hetero-microstructures based on pNIPAM. By variation of the local exposure dose in three-dimensional laser lithography, we demonstrate that the material parameters can be altered on demand in a single resist formulation. We explore this concept for sophisticated three-dimensional architectures with large-amplitude and complex responses. The experimental results are consistent with numerical calculations, able to predict the actuation response. Furthermore, a spatially controlled response is achieved by inducing a local temperature increase by two-photon absorption of focused light.
关键词： light-induced actuation,pNIPAM,temperature response,stimuli-responsive materials,gray-tone lithography,hetero-microstructures,laser lithography,3D microstructures
更新于2025-09-23 15:22:29
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Trap-assisted enhanced bias illumination stability of oxide thin film transistor by praseodymium doping
摘要： Praseodymium-doped indium zinc oxide (PrIZO) have been employed as the channel layer of thin film transistors (TFTs). The TFTs with Pr doping exhibited a remarkable suppression of the light induced instability. A negligible photo-response and remarkable enhancement in negative gate bias stress under illumination (NBIS) were achieved in the PrIZO-TFTs. Meanwhile, the PrIZO-TFTs showed reasonable characteristics with a high field effect mobility of 26.3 cm2/Vs, SS value of 0.28 V/decade, and Ion/Ioff ratio of 108. X-ray photoelectron spectroscopy (XPS), microwave photoconductivity decay (Micro-PCD) and photoluminescence spectra (PL) were employed to analyze the effects of the Pr concentrations on the performance of PrIZO-TFTs. We disclosed that acceptor-like trap states induced by Pr ions might lead to the suppression of photo-induced carrier in conduction band, which is a new strategy for improving illumination stability of amorphous oxide semiconductors. Finally, a prototype of fully transparent AMOLED display was successfully fabricated to demonstrate the potential of Pr-doping TFTs applied in transparent devices.
关键词： Praseodymium doping,negative bias illumination stress,metal oxide,thin film transistor,photo-response
更新于2025-09-23 15:22:29
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Nonlinear optical response of a two-dimensional semi-Dirac system in terahertz regime
摘要： We demonstrate a strong nonlinear optical response in a two-dimensional semi-Dirac system in the terahertz regime. By applying the Boltzmann transport theory for the intra-band process and a quantum mechanics method for the inter-band process, we obtained the three-photon current response. It is found that both the intra- and inter-band excitations make significant contributions to the nonlinear response. The third order conductivities (TOCs) σyy(3) are about two magnitudes higher than that of σxx(3). Interestingly, for the inter-band TOCs, there is a sign change when the chemical potential varies across the saddle point in the conduction band in kx direction (that is parabolic), due to the competition between the two opposite nonlinear current contributed by the electrons at states k > kD and k < kD, respectively. Finally, we show that the nonlinear response in terahertz regime is significant at experimentally accessible field strengths. Our results suggest that this system could be of potential applications in photonic device for frequency up-conversion.
关键词： black phosphorous,semi-Dirac system,nonlinear optical response,Boltzmann transport theory
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - A CMUT - Based Electronic Nose for Real- Time Monitoring of Volatiles Emitted by Plants: Preliminary Results
摘要： Plants give off a unique profile of volatile organic compounds (VOCs) in response to abiotic and biotic stresses. The ability to discern specific VOC profiles provides for the early detection and subsequent treatment of insect infestation and pathogen infection. This work presents an electronic nose (e-nose) system based on a capacitive micromachined ultrasonic transducer (CMUT) with real-time monitoring capability for detecting and discriminating VOCs. Preliminary results show the almost instantaneous detection of the plant volatiles released systemically in response to physical wounding of plant tissue.
关键词： e-nose,real-time monitoring,plant stressors,volatile profile,gravimetric sensing,response fingerprint
更新于2025-09-23 15:22:29
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[ACM Press the 24th ACM Symposium - Tokyo, Japan (2018.11.28-2018.12.01)] Proceedings of the 24th ACM Symposium on Virtual Reality Software and Technology - VRST '18 - An evaluation of pupillary light response models for 2D screens and VR HMDs
摘要： Pupil diameter changes have been shown to be indicative of user engagement and cognitive load for various tasks and environments. However, it is still not the preferred physiological measure for applied settings. This reluctance to leverage the pupil as an index of user engagement stems from the problem that in scenarios where scene brightness cannot be controlled, the pupil light response confounds the cognitive-emotional response. What if we could predict the light response of an individual’s pupil, thus creating the opportunity to factor it out of the measurement? In this work, we lay the groundwork for this research by evaluating three models of pupillary light response in 2D, and in a virtual reality (VR) environment. Our results show that either a linear or an exponential model can be fit to an individual participant with an easy-to-use calibration procedure. This work opens several new research directions in VR relating to performance analysis and inspires the use of eye tracking beyond gaze as a pointer and foveated rendering.
关键词： light response,Eyetracking,pupil dilation,virtual reality,videos
更新于2025-09-23 15:22:29
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Optimizing a Portable ERG Device for Glaucoma Clinic: The Effect of Interstimulus Frequency on the Photopic Negative Response
摘要： Purpose: The purpose of this study was to investigate the effect of interstimulus frequency on the photopic negative response (PhNR) in the clinical electroretinogram (ERG) in glaucoma and healthy eyes. Methods: Participants with open angle glaucoma (n = 15) and age-matched controls (n = 20) were recruited. Photopic ERGs were recorded in one eye using five frequencies (1–5 Hz) delivered in random order. ERGs were analyzed for changes to amplitude and timing between groups and interstimulus frequency. Coefficient of variation (CoV) was used to examine variability within recordings for each frequency. Results: While the a-wave and b-wave showed minimal alteration, the PhNR was highly sensitive to changes in interstimulus frequency. The PhNR signal was largest at 1 Hz and steadily diminished with higher frequencies in both control and glaucoma groups. Significant differences in PhNR amplitude were found between controls and glaucoma groups at 2 and 3 Hz. While 1 Hz delivered the largest PhNR, it also showed a significantly greater CoV compared to other frequencies. Conclusions: An interstimulus frequency of 2 Hz was optimal for recording the PhNR, creating a good balance between testing time and signal quality. A higher frequency could be used to further shorten clinical testing times; however, this may compromise its clinical utility by dampening the PhNR. Translational Relevance: Here we show the importance of considering flash interstimulus frequency when designing ERG protocols for recording the PhNR as while higher frequencies can shorten test times, they also have considerable effects on the PhNR.
关键词： glaucoma,photopic negative response,electroretinogram
更新于2025-09-23 15:22:29
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A Comparison of the RETeval Sensor Strip and DTL Electrode for Recording the Photopic Negative Response
摘要： Purpose: To compare the RETeval sensor strip and Dawson-Trick-Litzkow (DTL) electrodes for recording the photopic negative response (PhNR) using a portable electroretinogram (ERG) device in eyes with and without glaucoma. Methods: Twenty-six control and 31 glaucoma or glaucoma-suspect participants were recruited. Photopic ERGs were recorded with sensor strip and DTL electrodes in random order using the LKC RETeval device. Stimuli consisted of brief, red flashes (1.7 cd.s/m2) on a blue background (photopic 10 cd/m2). The PhNR amplitude was measured from baseline to trough and also expressed as a ratio over the b-wave amplitude. Results: The sensor strip-recorded PhNR amplitude was significantly attenuated (mean 6 standard deviation [SD], 4.8 6 2.1 vs. 12.7 6 4.8 lV, P , 0.0001), with lower signal-to-noise ratio (SNR; 5.5 6 2.1 vs. 8.1 6 3.9, P , 0.0001), and a trend toward a larger PhNR/b-wave ratio compared with DTL electrodes. The PhNR amplitude, implicit time and PhNR/b-wave ratio correlated with visual field mean light sensitivity, although this fell short of significance for the sensor strip recorded PhNR amplitude. The electrodes demonstrated similar intersession repeatability with a coefficient of repeatability of 627% and 628% for the DTL and sensor strip, respectively. Conclusions: Sensor strip electrodes are a viable alternative for recording reproducible PhNRs, especially when values are normalized to the b-wave. However, DTL electrodes should be considered in cases of attenuated PhNR, or in elevated noise levels, due to its better signal-to-noise quality. Translational Relevance: Sensor strip electrodes can simplify PhNR recordings in the clinic, potentially eliminating the need for an experienced operator.
关键词： electroretinography,PhNR,photopic negative response
更新于2025-09-23 15:22:29
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[ACM Press the 2nd International Conference - Chengdu, China (2018.06.16-2018.06.18)] Proceedings of the 2nd International Conference on Advances in Image Processing - ICAIP '18 - A Novel Experimental Technique for Recovering Camera Response Function for High Dynamic Range Imaging
摘要： Recovering the camera’s response function has wide application in computational photography and computer vision. Traditional computational approach using multiple differently exposed photographs is based on solving a constrained linear least square problem and can only recover the function up to a scaling factor. In this paper, we present a novel experiment based technique to recover the true response curves of specific sensors. Our method first measures the average pixel intensities of a neutrally-grey cardboard for the full range of the shutter speed and gain control values of the sensor. After a simple data smoothing procedure, the camera’s response function is recovered through simple table look-up. We have implemented our technique on different kinds of sensors and show that it works well. The new technique recover the actual range of the sensor and is more accurate than the computational technique. The procedure is easy to set up and simple to implement which will be useful for developing applications such as High Dynamic Ranging (HDR) imaging.
关键词： Exposure,Camera Response Curve,HDR
更新于2025-09-23 15:22:29
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Baseline Detrending for the Photopic Negative Response
摘要： Purpose: The photopic negative response (PhNR) of the light-adapted electroretinogram (ERG) holds promise as an objective marker of retinal ganglion cell function. We compared baseline detrending methods to improve PhNR repeatability without compromising its diagnostic ability in glaucoma. Methods: Photopic ERGs were recorded in 20 glaucoma and 18 age-matched control participants. A total of 50 brief, red-flashes (1.6 cd.s/m2) on a blue background (10 photopic cd/m2) were delivered using the RETeval device. Detrending methods compared were: (1) increasing the high-pass filter from 1 to 10 Hz and (2) estimating and removing the trend with an increasing polynomial (order from 1–10) applied to the prestimulus interval, prestimulus and postsignal interval, or the whole ERG signal. Coefficient of repeatability (COR%), unpaired Student’s t-test, and area under the receiver operating characteristic curve (AUC) were used to compare the detrending methods. Results: Most detrending methods improved PhNR test–retest repeatability compared to the International Society for Clinical Electrophysiology of Vision (ISCEV) recommended 0.3 to 300 Hz band-pass filter (COR% 6 200%). In particular, detrending with a polynomial (order 3) applied to the whole signal performed the best (COR% 6 44%) while achieving similar diagnostic ability as ISCEV band-pass (AUC 0.74 vs. 0.75, respectively). However, over-correcting with higher orders of processing can cause waveform distortion and reduce diagnostic ability. Conclusions: Baseline detrending can improve the PhNR repeatability without compromising its clinical use in glaucoma. Further studies exploring more complex processing methods are encouraged. Translational Relevance: Baseline detrending can significantly improve the quality of the PhNR.
关键词： electroretinogram,baseline detrending,glaucoma,photopic negative response
更新于2025-09-23 15:22:29