Recognition of a Virtual Maze Scene Using Simulated Prosthetic Vision.

A real-time psychological physics experimental platform was built to aid in discovering the best real-time image processing strategy for the limited number of electrodes, and in providing the most useful prosthetic implant visual information. A number of maze pathfinder tasks were performed at low resolution to simulate use by blind individuals in performing daily visual activities. In this study, simple (5 rows × 5 columns), medium (8 × 8), and complex (11 × 11) maze models were created in 3DMAX. The models were constructed by using Unity to build virtual scenes for real-time pixel processing, including binarization, color inversion, and matching to templates with three different resolutions (16 × 16, 24 × 24, 32 × 32). Subjects completed maze pathfinding tasks using 45° and 60° views of the labyrinth at the 32 × 32 resolution to determine the optimal viewing angle. The time required to find the maze entrance and complete the maze were analyzed along with the rate of maze completion (accuracy) at various resolutions. In the first experiment, the average time required to find the entrance and the average maze pathfinding duration were significantly longer at 60°. Therefore, the 45° view provided the best perspective. In the second experiment, the angle was fixed to 45°. As the maze difficulty increased, the average time needed to find the maze entrance decreased, but the average time required to complete the maze increased. When the difficulty of the maze was fixed, the time required to find the maze entrance and solve the maze decreased when the resolution increased. The accuracy with which the maze path was identified increased as well. The average maze pathfinding time at 24 × 24 was significantly less than at 16 × 16. A similar trend was observed when the average maze pathfinding times at 32 × 32 and 24 × 24 were compared. At 32 × 32, the average pathfinding accuracy was 100%. This indicates that 32 × 32 is an effective resolution for maze pathfinding.

Synthesis and antiviral activity of 2-substituted methylthio-5-(4-amino-2-methylpyrimidin-5-yl)-1,3,4-oxadiazole derivatives.

A series of novel 2-substituted methylthio-5-(4-amino-2-methylpyrimidin-5-yl-)-1,3,4-oxadiazole derivatives were synthesized and evaluated for antiviral activities against tobacco mosaic virus (TMV) via half-leaf method. The preliminary biological results showed that these compounds exhibited good antiviral activity against TMV in vivo. Among these compounds, compounds 8f, 8h, 8k, 8n, 8q and 8w exhibited the similar curative effect against TMV (EC50=290.98-438.29µg/mL) as the commercial product Ningnanmycin (301.83µg/mL). Notably, compound 8i exhibited the excellent curative effect against TMV, with EC50 value of 246.48µg/mL, which was better than that of Ningnanmycin. To the best of our knowledge, this was the first Letter of 2-substituted methylthio-5-(4-amino-2-methylpyrimidin-5-yl-)-1,3,4-oxadiazole derivatives with potent antiviral against TMV.

Photothermal controlled-release microcapsule pesticide delivery systems constructed with sodium lignosulfonate and transition metal ions: construction, efficacy and on-demand pesticide delivery.

BACKGROUND: Widespread application of controlled-release pesticide delivery systems is a feasible and effective method to improve the utilization efficiency of pesticides. However, owing to the high cost and complicated preparation technologies of controlled-release pesticide delivery systems, their applications in agricultural production have been seriously hindered. RESULTS: This study aimed to construct inexpensive photothermally controlled-release pesticide delivery systems using chitosan (CS) and sodium lignosulfonate (LS) as the wall materials, and a coordination assembly strategy of LS with transition metal ions to encapsulate a model pesticide, avermectin (AVM). The resulting complex or nanoparticle photothermal layers in these systems effectively achieved photothermal conversions, and replaced the use of common photothermal agents. In the prepared pesticide-delivery systems, two systems had remarkable photothermal conversion performance and photothermal stabilities with a photothermal conversion efficiency (η) of 24.03% and 28.82%, respectively, under 808 nm, 2 W near-infrared irradiation. The slow-release and ultraviolet-shielding performance of these two systems were markedly enhanced compared with other formulations. The insecticidal activities of these two systems against Plutella xylostella under irradiation with light-emitting diode (LED)-simulated sunlight were also enhanced by 5.20- and 5.06-fold, respectively, compared with that without irradiation of LED-simulated sunlight. CONCLUSION: Because of their convenient preparations, inexpensive and renewable raw materials, and excellent photothermally controlled-release performance, these on-demand pesticide delivery systems might have significant potential in improving the utilization efficiency of pesticides in modern agriculture. © 2024 Society of Chemical Industry.

Fabrication of a dual pH-responsive and photothermal microcapsule pesticide delivery system for controlled release of pesticides.

BACKGROUND: The development of stimulus-responsive and photothermally controlled-release microcapsule pesticide delivery systems is a promising solution to enhance the effective utilization and minimize the excessive use of pesticides in agriculture. RESULTS: In this study, an AVM@CS@TA-Fe microcapsule pesticide delivery system was developed using avermectin as the model drug, chitosan and tannic acid as the wall materials, and tannic acid-Fe complex layer as the photothermal agent. The optical microscope, scanning electron microscope, transmission electron microscope, and Fourier-transform infrared spectroscope were used to characterize the prepared microcapsule. The slow-release, UV-shielding, photothermal performance, and nematicidal activity of the microcapsule were systematically investigated. The results showed that the system exhibited excellent pH-responsive and photothermal-sensitive performances. In addition, the UV-shielding performance of the delivery system was improved. The photothermal conversion efficiency (η) of the system under the irradiation of near-infrared (NIR) light was determined to be 14.18%. Moreover, the nematicidal activities of the system against pine wood nematode and Aphelenchoides besseyi were greatly increased under the irradiation of light-emitting diode (LED) simulated sunlight. CONCLUSION: The release of the pesticide-active substances in such a pesticide delivery system could be effectively regulated with the irradiation of NIR light or LED-simulated sunlight. Thus, the developed pesticide delivery system may have broad application prospects in modern agriculture fields. © 2022 Society of Chemical Industry.

Graph-Collaborated Auto-Encoder Hashing for Multiview Binary Clustering.

Unsupervised hashing methods have attracted widespread attention with the explosive growth of large-scale data, which can greatly reduce storage and computation by learning compact binary codes. Existing unsupervised hashing methods attempt to exploit the valuable information from samples, which fails to take the local geometric structure of unlabeled samples into consideration. Moreover, hashing based on auto-encoders aims to minimize the reconstruction loss between the input data and binary codes, which ignores the potential consistency and complementarity of multiple sources data. To address the above issues, we propose a hashing algorithm based on auto-encoders for multiview binary clustering, which dynamically learns affinity graphs with low-rank constraints and adopts collaboratively learning between auto-encoders and affinity graphs to learn a unified binary code, called graph-collaborated auto-encoder (GCAE) hashing for multiview binary clustering. Specifically, we propose a multiview affinity graphs' learning model with low-rank constraint, which can mine the underlying geometric information from multiview data. Then, we design an encoder-decoder paradigm to collaborate the multiple affinity graphs, which can learn a unified binary code effectively. Notably, we impose the decorrelation and code balance constraints on binary codes to reduce the quantization errors. Finally, we use an alternating iterative optimization scheme to obtain the multiview clustering results. Extensive experimental results on five public datasets are provided to reveal the effectiveness of the algorithm and its superior performance over other state-of-the-art alternatives.

Preparation and performance of chlorfenapyr microcapsules with a degradable polylactide-based polyurethane wall material.

To improve the utilization rate of chlorfenapyr and make the wall material of chlorfenapyr microcapsules easily degradable, polylactide diol, toluene diisocyanate and 1,4-butanediol were used to prepare a chlorfenapyr microcapsule suspension by interfacial polymerization. The product was characterized by the methods of optical microscopy, scanning electron microscopy and Fourier-transform infrared spectroscopy. The results indicated that the microcapsule particles were spherical, with an encapsulation efficiency of 84.20%. The diluted product had good wetting and spreading abilities on cabbage leaves. Compared with other commercial formulations, the slow-release effect of the microcapsule suspension was more obvious and the release mechanisms conform to Fickian diffusion, with the release rate controllable by adjusting the external pH conditions. Furthermore, the wall material of the microcapsules showed good degradation performance in a phosphate-buffered solution. Microencapsulation by this method significantly increased the validity period of chlorfenapyr and the wall material was also degraded easily.

Construction of a photothermal controlled-release microcapsule pesticide delivery system.

This study aimed to achieve the controlled-release of bioactive ingredients in microcapsule pesticide delivery systems. A photothermal controlled-release microcapsule pesticide delivery system was constructed using chitosan and polydopamine (PDA) as the wall materials to encapsulate avermectin. All the prepared microcapsules were characterized by the methods of optical microscopy, scanning electron microscopy, transmission electron microscopy, and Fourier-transform infrared spectroscopy. The slow-release, UV-shielding, photothermal performance, and the nematicidal activity of the prepared microcapsules were also systematically investigated. The results indicated that the prepared microcapsules had excellent slow-release and UV-shielding performance when further encapsulated with the PDA layer relative to those of the non-PDA-encapsulated products. The photothermal sensitivity of the AVM@CS/CMA/PDA composite microcapsule under the irradiation of near-infrared light (NIR) was dramatically enhanced with the photothermal conversion efficiency (η) of 14.93%. Furthermore, the nematicidal activity of the AVM@CS/CMA/PDA composite microcapsule system was effectively improved on exposure to the irradiation of a light-emitting diode (LED) full-spectrum light. The strategies used in this study for developing the photothermal controlled-release pesticide delivery system might play an important role on improving utilization of pesticides.

A four-armed Schiff base: 6,6',6'',6'''-tetra-meth-oxy-2,2',2'',2'''-[methanetetra-yltetra-kis(methylenenitrilo-methyl-idyne)]tetra-phenol.

In the structure of the title compound, C(37)H(40)N(4)O(8), penta-erythrityltetra-mine is bonded to four o-vanillin mol-ecules, forming a four-armed Schiff base mol-ecule. These mol-ecules are connected by inter-molecular C-H⋯O hydrogen bonds. Intramolecular C-H⋯N and O-H⋯N hydrogen bonds are also present.

Recognition of a Virtual Scene via Simulated Prosthetic Vision.

In order to effectively aid the blind with optimal low-resolution vision and visual recovery training, pathfinding and recognition tests were performed using a simulated visual prosthetic scene. Simple and complex virtual scenes were built using 3DMAX and Unity, and pixelated to three different resolutions (32 × 32, 64 × 64, and 128 × 128) for real-time pixel processing. Twenty subjects were recruited to complete the pathfinding and object recognition tasks within the scene. The recognition accuracy and time required were recorded and analyzed after the trials. In the simple simulated prosthetic vision (SPV) scene, when the resolution was increased from 32 × 32 to 48 × 48, the object recognition time decreased from 92.19 ± 6.97 to 43.05 ± 6.08 s, and the recognition accuracy increased from 51.22 ± 8.53 to 85.52 ± 4.93%. Furthermore, the number of collisions decreased from 10.00 ± 2.31 to 3.00 ± 0.68. When the resolution was increased from 48 × 48 to 64 × 64, the object recognition time further decreased from 43.05 ± 6.08 to 19.46 ± 3.71 s, the recognition accuracy increased from 85.52 ± 4.93 to 96.89 ± 2.06%, and the number of collisions decreased from 3.00 ± 0.68 to 1.00 ± 0.29. In complex scenes, the time required to recognize the room type decreased from 115.00 ± 23.02 to 68.25 ± 17.23 s, and object recognition accuracy increased from 65.69 ± 9.61 to 80.42 ± 7.70% when the resolution increased from 48 × 48 to 64 × 64. When the resolution increased from 64 × 64 to 128 × 128, the time required to recognize the room type decreased from 68.25 ± 17.23 to 44.88 ± 9.94 s, and object recognition accuracy increased from 80.42 ± 7.71 to 85.69 ± 7.39%. Therefore, one can conclude that there are correlations between pathfinding and recognition. When the resolution increased, the time required for recognition decreased, the recognition accuracy increased, and the number of collisions decreased. Although the subjects could partially complete the recognition task at a resolution of 32 × 32, the recognition time was too long and recognition accuracy was not good enough to identify simple scenes. Complex scenes required a resolution of at least 48 × 48 for complete recognition. In addition, increasing the resolution shortened the time required to identify the type of room, and improved the recognition accuracy.