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Unmanned aerial vehicle-based hyperspectral imaging (HSI) and machine learning (ML) techniques are applied for crop field data collection such as yield, nitrogen content, leaf chlorophyll, biomass estimation, leaf area index (LAI), and biotic and abiotic stress. It is very difficult to identify with certainty best practices for specific applications and for targeted crop species because the results are frequently contradictory; models or indices sometimes perform well, but other times they do not. ML and HSI are useful and sophisticated techniques, but treating them as first-option methods may be detrimental in the long term. Favoring HSI in situations where a multispectral sensor performs equally well only delays end-user adoption of technology owing to cost and complexity. The past few years have seen increased interest in unmanned aerial vehicle (UAV)-based hyperspectral imaging (HSI) and machine learning (ML) in agricultural research, concomitant with an increase in published research on these topics. We provide an updated review, written for agriculturalists, highlighting the benefits in the retrieval of biophysical parameters of crops via UAVs relative to less sophisticated options. We reviewed >70 recent papers and found few consistent results between similar studies. Owing to their high complexity and cost, especially when applied to crops of low value, the benefits of most of the research reviewed are difficult to explain. Future effort will be necessary to distill research findings into lower-cost options for end-users. [ABSTRACT FROM AUTHOR]

Monte Carlo simulations are crucial for calculating magnetic field correction factors k B for the dosimetry in external magnetic fields. As in Monte Carlo codes the charged particle transport is performed in straight condensed history (CH) steps, the curved trajectories of these particles in the presence of external magnetic fields can only be approximated. In this study, the charged particle transport in presence of a strong magnetic field B → was investigated using the Fano cavity test. The test was performed in an ionization chamber and a diode detector, showing how the step size restrictions must be adjusted to perform a consistent charged particle transport within all geometrical regions. Monte Carlo simulations of the charged particle transport in a magnetic field of 1.5 T were performed using the EGSnrc code system including an additional EMF-macro for the transport of charged particle in electro-magnetic fields. Detailed models of an ionization chamber and a diode detector were placed in a water phantom and irradiated with a so called Fano source, which is a monoenergetic, isotropic electron source, where the number of emitted particles is proportional to the local density. The results of the Fano cavity test strongly depend on the energy of charged particles and the density within the given geometry. By adjusting the maximal length of the charged particle steps, it was possible to calculate the deposited dose in the investigated regions with high accuracy (< 0.1 %). The Fano cavity test was performed in all regions of the detailed detector models. Using the default value for the step size in the external magnetic field, the maximal deviation between Monte Carlo based and analytical dose value in the sensitive volume of the ion chamber and diode detector was 8% and 0.1%, respectively. The Fano cavity test is a crucial validation method for the modeled detectors and the transport algorithms when performing Monte Carlo simulations in a strong external magnetic field. Special care should be given, when calculating dose in volumes of low density. This study has shown that the Fano cavity test is a useful method to adapt particle transport parameters for a given simulation geometry. [ABSTRACT FROM AUTHOR]

Fibroblasts play a key role in stricture formation in Crohn's disease (CD) but understanding its pathogenesis requires a systems-level investigation to uncover new treatment targets. We studied full-thickness CD tissues to characterize fibroblast heterogeneity and function by generating the first single-cell RNA sequencing (scRNAseq) atlas of strictured bowel and providing proof of principle for therapeutic target validation. We performed scRNAseq of 13 fresh full-thickness CD resections containing noninvolved, inflamed nonstrictured, and strictured segments as well as 7 normal non-CD bowel segments. Each segment was separated into mucosa/submucosa or muscularis propria and analyzed separately for a total of 99 tissue samples and 409,001 cells. We validated cadherin-11 (CDH11) as a potential therapeutic target by using whole tissues, isolated intestinal cells, NanoString nCounter, next-generation sequencing, proteomics, and animal models. Our integrated dataset revealed fibroblast heterogeneity in strictured CD with the majority of stricture-selective changes detected in the mucosa/submucosa, but not the muscle layer. Cell-cell interaction modeling revealed CXCL14+ as well as MMP/WNT5A+ fibroblasts displaying a central signaling role in CD strictures. CDH11, a fibroblast cell-cell adhesion molecule, was broadly expressed and up-regulated, and its profibrotic function was validated using NanoString nCounter, RNA sequencing, tissue target expression, in vitro gain- and loss-of-function experiments, proteomics, and knock-out and antibody-mediated CDH11 blockade in experimental colitis. A full-thickness bowel scRNAseq atlas revealed previously unrecognized fibroblast heterogeneity and interactions in CD strictures and CDH11 was validated as a potential therapeutic target. These results provide a new resource for a better understanding of CD stricture formation and open potential therapeutic developments. This work has been posted as a preprint on Biorxiv under doi: 10.1101/2023.04.03.534781. [Display omitted] This work creates an understanding of which cell types are present in Crohn's disease strictures and control tissues and how they interact with each other to cause disease. These findings were used to identify a potential novel treatment target. [ABSTRACT FROM AUTHOR]

Lattice Radiation Therapy, a form of spatially fractionated radiation therapy (SFRT) delivers non-uniform dose distributions comprised of characteristic high- and low-dose spheres of 100% and 30% of prescription, respectively. Neoadjuvant SFRT of locally advanced head and neck cancer (HNC) has shown increased local control and possible reduction of distant metastasis with clinically acceptable long-term toxicities. This study evaluates three treatment planning approaches with varying levels of automation for clinical goal compliance and time efficiency. These use automated and manual beam geometry and dosimetric optimization tools to evaluate tradeoffs in clinical compliance and efficiency. Five patients with locally-advanced HNC (N3+) were prescribed 15 Gy in 1 fraction. High-dose spheres (PTV_High) 1 cm in diameter were placed 1.8 cm apart (center-to-center) within rGTV (5mm inner margin from GTV), avoiding critical organs. Low-dose spheres (PTV_Avoid) 1cm in diameter were placed equidistant between the high-dose spheres in the four cardinal directions. Treatment planning approaches of automated SRS (HA), manual SBRT (mSBRT), and hybrid (HA-mSBRT) were utilized. The hybrid approach utilized the automatically optimized beam geometry obtained in the HA process but forewent the use of an automatic SRS NTO for manually determined NTO parameters and dose optimization structures. Plans were normalized for identical target coverage (PTV_HighD95% = 100%). Clinical goal compliance including OAR dose, and dose gradients were evaluated, in addition to total planning time for evaluation of time efficiency. Total average planning times were 185 minutes (HA), 183 minutes (mSBRT), and 167 minutes (HA-mSBRT). OAR doses exceeded a 2 Gy max dose goal 20, 17, and 17 times for HA, mSBRT and HA-mSBRT for 5 patients each. Additional to the increased frequency of OAR tolerance breaches, HA lowered the minimum target dose and significantly lengthened the optimization time. The ratio of PTV_High to PTV_Avoid mean dose was 4.09 (HA), 3.76 (mSBRT), and 3.92 (HA-mSBRT). Dose drop-off, as measured by the ratio of median dose to standard deviation of dose within a 5 mm ring surrounding PTV_High was 2.608 (HA), 2.489 (mSBRT), and 2.610 (HA-mSBRT). The above metrics quantify the dose heterogeneity necessary for SFRT plan quality by evaluating the dose difference between high and low regions and dose gradient steepness between prescribed high and low-dose regions. The mSBRT method was the most MU-efficient, using only 1.5 MUs per cGy-degree, in contrast to approximately 2.7 for both the HA and HA-mSBRT methods. The HA-mSBRT strategy demonstrates the highest clinical goal compliance with high OAR sparing, high dose gradient, and dose uniformity, while being both MU- and time-efficient. This semi-automated approach should provide a feasible solution for prospective use of SFRT in HNC. [ABSTRACT FROM AUTHOR]