A Reconstruction Method for Hyperspectral Remote Sensing Reflectance in the Visible Domain and Applications

A reconstruction method was developed for hyperspectral remote sensing reflectance (Rrs)data in the visible domain (400–700 nm) based on in situ observations. A total of 2,647 Rrs spectra were collected over a wide variety of water environments including open ocean, coastal and inland waters. Ten schemes with different band numbers (6 to 15) were tested based on a nonlinear model. It was found that the accuracy of the reconstruction increased with the increase of input band numbers. Eight of these schemes met the accuracy criterion with the mean absolute error (MAE) and mean relative error (MRE)values between reconstructed and in situ Rrs less than 0.00025 sr-1 and 5%, respectively. We chose the eight-band scheme for further evaluation because of its decent performance. The results revealed that the parameterization derived by the eight-band scheme was efficient for restoring Rrs spectra from different water bodies. In contrast to the previous studies that used a linear model with 15 spectral bands, the nonlinear model with the eight-band scheme yielded a comparable reconstruction performance. The MAE andMRE values were generally less than 0.00016 sr-1 and 3% respectively; much lower than the uncertainties in satellite-derived Rrs products. Furthermore, a preliminary experiment of this method on the data from the Hyperspectral Imager for the Coastal Ocean (HICO) showed high potential in the future applications for reconstructing Rrs spectra from space-borne optical sensors. Overall, the eight-band scheme with our non-linear model was proven to be optimal for hyperspectral Rrs reconstruction in the visible domain

An efficient headland-turning navigation system for a safflower picking robot

This study proposes a navigation system for the headland autonomous turning of a safflower picking robot. The proposed system includes binocular cameras, differential satellites, and inertial sensors. The method of extracting the headland boundary line combining the hue, saturation, and value-fixed threshold segmentation method and random sample consensus algorithm and planning the headland-turning trajectory of a robot based on the multiorder Bezier curve are used as control methods. In addition, a headland-turning tracking model of a safflower picking robot is designed, and a path-tracking control algorithm is developed. A field test verifies the performance of the designed headland-turning navigation system. The test results show that the accuracy of the judgment result regarding the existence of a headland is higher than 96%. In headland boundary detection, the angle deviation is less than 1.5˚, and the depth value error is less than 50 mm. The headland-turning path tracking test result shows that at a turning speed of 0.5 km/h, the average lateral deviation is 37 mm, and the turning time is 24.2 seconds. Compared to the 1 km/h, the turning speed of 0.5 km/h provides a better trajectory tracking effect, but the turning time is longer. The test results verify that this navigation system can accurately extract the headland boundary line and can successfully realise the headland-turning path tracking of a safflower picking robot. The results presented in this study can provide a useful reference for the autonomous navigation of a field robot

Dynamic profiling of intact glucosinolates in radish by combining UHPLC-HRMS/MS and UHPLC-QqQ-MS/MS

Glucosinolates (GSLs) and their degradation products in radish confer plant defense, promote human health, and generate pungent flavor. However, the intact GSLs in radish have not been investigated comprehensively yet. Here, an accurate qualitative and quantitative analyses of 15 intact GSLs from radish, including four major GSLs of glucoraphasatin (GRH), glucoerucin (GER), glucoraphenin (GRE), and 4-methoxyglucobrassicin (4MGBS), were conducted using UHPLC-HRMS/MS in combination with UHPLC-QqQ-MS/MS. Simultaneously, three isomers of hexyl GSL, 3-methylpentyl GSL, and 4-methylpentyl GSL were identified in radish. The highest content of GSLs was up to 232.46 μmol/g DW at the 42 DAG stage in the ‘SQY’ taproot, with an approximately 184.49-fold increase compared to the lowest content in another sample. That the GSLs content in the taproots of two radishes fluctuated in a similar pattern throughout the five vegetative growth stages according to the metabolic profiling, whereas the GSLs content in the ‘55’ leaf steadily decreased over the same period. Additionally, the proposed biosynthetic pathways of radish-specific GSLs were elucidated in this study. Our findings will provide an abundance of qualitative and quantitative data on intact GSLs, as well as a method for detecting GSLs, thus providing direction for the scientific progress and practical utilization of GSLs in radish

Radial Retinotomies with Endodiathermy for Severe Proliferative Vitreoretinopathy: Short-Term Results

Purpose. Retinal redetachment of silicone oil-filled eyes continues to be a frustrating condition that typically requires retinectomy. We proposed radial retinotomy as a potentially less invasive surgery. Here, we preliminarily explored its feasibility, efficacy, and safety. Methods. Totally 9 eyes of 9 consecutive patients were included in a prospective noncomparative trial. A series of retinotomies were created by endodiathermy in a radial pattern to relax the foreshortened retina. The eye was refilled with fresh silicone oil. The treated eyes were examined via visual acuity (VA) tests, tonometry, slit-lamp microscopy, and fundus photography during a 6-month observation period. Results. The procedure was completed in an average of 28 minutes from silicone oil removal to fresh silicone oil placement. Fundus photography demonstrated that 7 of the 9 eyes (78%) exhibited retinal reattachment. On average, VA was significantly improved within the first 2 weeks (P=0.02) and remained stable for the following 6 months. The change in intraocular pressure was not significant (P=0.76), and no adverse event was observed (0%). Conclusion. Radial retinotomies with endodiathermy were shown to be feasible, effective, and safe in selected cases of inferior contracted retina without vitreous base fibrosis over a 6-month observation period. This trial is registered with NCT02201706

Design and Test of a Levelling System for a Mobile Safflower Picking Platform

At this stage, safflower picking is mostly performed manually or semi-manually, the picking method is antiquated and the picking precision is low. In this experimental study, a new attitude tilt levelling system was designed for a safflower-picking robot, which has created a solid foundation for the realization of future safflower-picking machine automation. The mobile platform was simplified as a four-point support, and an automatic levelling control system was designed based on the multi-sensor data collected by a multi-inclination sensor, a multi-pressure sensor, and a displacement sensor. The error range of the levelling of the mobile platform was obtained by MATLAB simulation analysis, the relationship between the inclination of the mobile platform and the displacement of the levelling mechanism was analyzed by coordinate transformation, and the maximum levelling range of the levelling mechanism was analyzed. On this basis, an automatic levelling control system was designed. Finally, the safflower-picking mobile platform was tested, and we concluded that the levelling control system can adjust the inclination angle of the mobile platform to within 0.2° and the levelling time to within 7 s. The design of the automatic levelling control system fills the gap in the field of safflower picking and adopts multi-sensor fusion. Compared with other methods, the collected inclination data is more accurate, the levelling accuracy higher, and the levelling time shorter. The final results show that this experimental study provides a strong basis for the realization of the full-mechanical automation of safflower picking

Q and Zheng H: Migration of retinal pigment epithelium cells is regulated by protein kinase Calpha in vitro. Invest Ophthalmol Vis Sci 54

PURPOSE. Retinal pigment epithelium (RPE) cell migration and proliferation are considered key elements in proliferative vitreoretinopathy (PVR). Downregulation of protein kinase Ca (PKCa) can inhibit RPE cell proliferation. Here, we sought to analyze whether PKCa affects the migration of RPE cells. METHODS. Human RPE (hRPE) cells were cultured, confirmed by immunofluorescence staining, and divided into four groups: control, thymeleatoxin, non-small interfering RNA (siRNA), and siRNA-PKCa. Thymeleatoxin was used to activate PKCa, and siRNA-PKCa was used to knock it down. Expression of PKCa was confirmed by quantitative RT-PCR (qRT-PCR). Cell migration ability was analyzed by wound healing assay and transwell chamber assay. Expression of zonula occludens (ZO)-1 and occludin was determined by immunofluorescence. RESULTS. Pure populations of hRPE cell cultures were observed using light and fluorescence microscopy. The mRNA levels of PKCa were not significantly increased by thymeleatoxin, but were reduced by siRNA-PKCa as determined by qRT-PCR assay. The wound healed faster in the thymeleatoxin group than in the control group at time points 12, 15, and 20 hours. The wound healed more slowly in the siRNA-PKCa group than in the non-siRNA group at the three time points. A similar tendency among the four groups was consistently observed in regard to cell numbers counted in the transwell chamber assay. The expression of ZO-1 was highest in the siRNA-PKCa group, similar in the control and non-siRNA groups, and lowest in the thymeleatoxin group. After migration, the fluorescence intensity of ZO-1 was reduced to similarly weak levels among the four groups. CONCLUSIONS. Retinal pigment epithelium cell migration is enhanced by a PKCa agonist and suppressed by a PKCa antagonist. The results suggest that a PKCa-mediated signal transduction pathway plays a crucial role in hRPE cell migration and may be a potential therapeutic target against hRPE cell migration and PVR disease

Turbidity Estimation from GOCI Satellite Data in the Turbid Estuaries of China’s Coast

Knowledge of the distribution and variation of water turbidity directly represent important information related to the marine ecology and multiple biogeochemical processes, including sediment transport and resuspension and heat transfer in the upper water layer. In this study, a neural network (NN) approach was applied to derive the water turbidity using the geostationary ocean color imager (GOCI) data in turbid estuaries of the Yellow River and the Yangtze River. The results showed a good agreement between the GOCI-derived turbidity and in situ measured data with a determination coefficient (R2) of 0.84, root mean squared error (RMSE) of 58.8 nephelometric turbidity unit (NTU), mean absolute error of 25.1 NTU, and mean relative error of 34.4%, showing a better performance than existing empirical algorithms. The hourly spatial distributions of water turbidity in April 2018 suggested that high turbidity regions were distributed in the Yellow River estuary, Yangtze River estuary, Hangzhou Bay, and coastal waters of Zhejiang Province. Furthermore, the relationship between water turbidity and tide were estimated. A defined turbid zone was defined to evaluate the diurnal variations of turbidity, which has subtle changes at different times. Our results showed an inverse relationship between turbidity and tide over six selected stations, i.e., when the value of turbidity is high, then the corresponding tidal height is usually low, and vice versa. The combined effects of tidal height and tidal currents could explain the phenomena, and other factors such as winds also contribute to the turbidity distributions

Giant Helical Dichroism of Single Chiral Nanostructures with Photonic Orbital Angular Momentum

10.1021/acsnano.0c08941ACS Nan