Search Results (6)

To address the challenges of low pesticide utilization, insufficient automation, and health risks in orchard plant protection, we developed an autonomous spraying vehicle using ArduPilot firmware and a robot operating system (ROS). The system tackles orchard navigation hurdles, including global navigation satellite system (GNSS) signal obstruction, light detection and ranging (LIDAR) simultaneous localization and mapping (SLAM) error accumulation, and lighting-limited visual positioning. A key innovation is the integration of an extended Kalman filter (EKF) to dynamically fuse T265 visual odometry, inertial measurement unit (IMU), and GPS data, overcoming single-sensor limitations and enhancing positioning robustness in complex environments. Additionally, the study optimizes PID controller derivative parameters for tracked chassis, improving acceleration/deceleration control smoothness. The system, composed of Pixhawk 4, Raspberry Pi 4B, Silan S2L LIDAR, T265 visual odometry, and a Quectel EC200A 4G module, enables autonomous path planning, real-time obstacle avoidance, and multi-mission navigation. Indoor/outdoor tests and field experiments in Sun Village Orchard validated its autonomous cruising and obstacle avoidance capabilities under real-world orchard conditions, demonstrating feasibility for intelligent plant protection. Full article

Background: Although belonging to different branches of the immune system, cytotoxic CD8⁺ αβ T cells and γδ T cells utilize common cytolytic effectors including FasL, granzymes, perforin and granulysin. The effector proteins are stored in different subsets of lysosome-related effector vesicles (LREVs) and released to the immunological synapse upon target cell encounter. Notably, in activated cells, LREVs and potentially other vesicles are continuously produced and released as extracellular vesicles (EVs). Presumably, EVs serve as mediators of intercellular communication in the local microenvironment or at distant sites. Methods: EVs of activated and expanded cytotoxic CD8⁺ αβ T cells or γδ T cells were enriched from culture supernatants by differential and ultracentrifugation and characterized by nanoparticle tracking analyses and Western blotting. For a comparative proteomic profiling, EV preparations from both cell types were isobaric labeled with tandem mass tags (TMT10plex) and subjected to mass spectrometry analysis. Results: 686 proteins were quantified in EV preparations of cytotoxic CD8⁺ αβ T cells and γδ T cells. Both populations shared a major set of similarly abundant proteins, while much fewer proteins presented higher abundance levels in either CD8⁺ αβ T cells or γδ T cells. To our knowledge, we provide the first comparative analysis of EVs from cytotoxic CD8⁺ αβ T cells and γδ T cells. Full article

Wheat is one of the world’s crucial staple food crops. In turn, einkorn wheat (Triticum monococcum L.) is considered a wild relative of wheat (Triticum aestivum L.) and can be used as a source of agronomically important genes for breeding purposes. Cultivated T. monococcum subsp. monococcum originated from T. monococcum subsp. aegilopoides (syn. T. boeticum). For the better utilization of valuable genes from these species, it is crucial to discern the genetic diversity at their cytological and molecular levels. Here, we used a fluorescence in situ hybridization toolbox and molecular markers linked to the leaf rust resistance gene Lr63 (located on the short arm of the 3A^m chromosome—3A^mS) to track the polymorphisms between T. monococcum subsp. monococcum, T. boeticum and T. urartu (A-genome donor for hexaploid wheat) accessions, which were collected in different regions of Europe, Asia, and Africa. We distinguished three groups of accessions based on polymorphisms of cytomolecular and leaf rust resistance gene Lr63 markers. We observed that the cultivated forms of T. monococcum revealed additional marker signals, which are characteristic for genomic alternations induced by the domestication process. Based on the structural analysis of the 3A^mS chromosome arm, we concluded that the polymorphisms were induced by geographical dispersion and could be related to adaptation to local environmental conditions. Full article

Trilateration-based target localization using received signal strength (RSS) in a wireless sensor network (WSN) generally yields inaccurate location estimates due to high fluctuations in RSS measurements in indoor environments. Improving the localization accuracy in RSS-based systems has long been the focus of a substantial amount of research. This paper proposes two range-free algorithms based on RSS measurements, namely support vector regression (SVR) and SVR + Kalman filter (KF). Unlike trilateration, the proposed SVR-based localization scheme can directly estimate target locations using field measurements without relying on the computation of distances. Unlike other state-of-the-art localization and tracking (L&T) schemes such as the generalized regression neural network (GRNN), SVR localization architecture needs only three RSS measurements to locate a mobile target. Furthermore, the SVR based localization scheme was fused with a KF in order to gain further refinement in target location estimates. Rigorous simulations were carried out to test the localization efficacy of the proposed algorithms for noisy radio frequency (RF) channels and a dynamic target motion model. Benefiting from the good generalization ability of SVR, simulation results showed that the presented SVR-based localization algorithms demonstrate superior performance compared to trilateration- and GRNN-based localization schemes in terms of indoor localization performance. Full article

This work presents a novel method for the non-invasive, in-line monitoring of mixing processes in microchannels using the Raman photometric technique. The measuring set-up distinguishes itself from other works in this field by utilizing recent state-of-the-art customized photon multiplier (CPM) detectors, bypassing the use of a spectrometer. This addresses the limiting factor of integration times by achieving measuring rates of 10 ms. The method was validated using the ternary system of toluene–water–acetone. The optical measuring system consists of two functional units: the coaxial Raman probe optimized for excitation at a laser wavelength of 532 nm and the photometric detector centered around the CPMs. The spot size of the focused laser is a defining factor of the spatial resolution of the set-up. The depth of focus is measured at approx. 85 µm with a spot size of approx. 45 µm, while still maintaining a relatively high numerical aperture of 0.42, the latter of which is also critical for coaxial detection of inelastically scattered photons. The working distance in this set-up is 20 mm. The microchannel is a T-junction mixer with a square cross section of 500 by 500 µm, a hydraulic diameter of 500 µm and 70 mm channel length. The extraction of acetone from toluene into water is tracked at an initial concentration of 25% as a function of flow rate and accordingly residence time. The investigated flow rates ranged from 0.1 mL/min to 0.006 mL/min. The residence times from the T-junction to the measuring point varies from 1.5 to 25 s. At 0.006 mL/min a constant acetone concentration of approx. 12.6% was measured, indicating that the mixing process reached the equilibrium of the system at approx. 12.5%. For prototype benchmarking, comparative measurements were carried out with a commercially available Raman spectrometer (RXN1, Kaiser Optical Systems, Ann Arbor, MI, USA). Count rates of the spectrophotometer surpassed those of the spectrometer by at least one order of magnitude at identical target concentrations and optical power output. The experimental data demonstrate the suitability and potential of the new measuring system to detect locally and time-resolved concentration profiles in moving fluids while avoiding external influence. Full article

Lymantria dispar L. (Lepidoptera: Erebidae) is an international quarantine pest with many hosts, widely distributed in Asia, Europe, and America. L. dispar is distributed mainly in the Eastern Monsoon Region of China. Currently, the most effective means of prevention and control of this pest are timely monitoring and early warning. However, their implementation is usually hampered by the lack of feasible methods and tools for fast tracking and traceability. Stable isotope technology can be used for material traceability, but in China, it is rarely employed for insect traceability. Therefore, using L. dispar as an example, we conducted a case study to explore the feasibility of using hydrogen stable isotopes for pest-source traceability. The grid data of hydrogen stable isotopes of global precipitation were downloaded from the Online Isotopes in Precipitation Calculator (OIPC; Bowen and Revenaugh, 2003, Bowen, 2017), and then, a zoning map of hydrogen stable isotopes of precipitation in mainland China was constructed using ArcGIS 10.4.1 (Esri, Redlands, CA, USA). The wings of 284 L. dispar adults captured in five regions in China were selected as experimental samples. A Finnigan Delta V Advantage Isotope Ratio Mass Spectrometer (Thermo Fisher Scientific, Inc., Waltham, Massachusetts, U.S.) and a Flash 2000 HT Elemental Analyzer (Thermo Fisher Scientific, Inc., Waltham, Massachusetts, U.S.) were used to measure the hydrogen stable isotope (δ²H) value of the samples. Then, using the recorded local precipitation hydrogen stable isotope of the sampling site, we performed a data simulation using R software (v.3.2.1; R Development Core Team, Vienna, Austria). A linear regression equation was next established: y = 1.186x − 13.247, where x represents the hydrogen stable isotope ratio of precipitation and y denotes the hydrogen stable isotope ratio of L. dispar. The t-test, F-test, and R² test results confirmed the high significance and matching with the simulation data used in the model. To further verify the accuracy of the model, L. dispar samples from Chengdu in Sichuan Province were collected for model back-testing. The verification results also evidenced that the actual source of the L. dispar sample can be obtained based on the method applied and the model developed in this paper. Full article