A model for phenotyping crop fractional vegetation cover using imagery from unmanned aerial vehicles.

Fractional vegetation cover (FVC) is the key trait of interest for characterizing crop growth status in crop breeding and precision management. Accurate quantification of FVC among different breeding lines, cultivars, and growth environments is challenging, especially because of the large spatiotemporal variability in complex field conditions. This study presents an ensemble modeling strategy for phenotyping crop FVC from unmanned aerial vehicle (UAV)-based multispectral images by coupling the PROSAIL model with a gap probability model (PROSAIL-GP). Seven field experiments for four main crops were conducted, and canopy images were acquired using a UAV platform equipped with RGB and multispectral cameras. The PROSAIL-GP model successfully retrieved FVC in oilseed rape (Brassica napus L.) with coefficient of determination, root mean square error (RMSE), and relative RMSE (rRMSE) of 0.79, 0.09, and 18%, respectively. The robustness of the proposed method was further examined in rice (Oryza sativa L.), wheat (Triticum aestivum L.), and cotton (Gossypium hirsutum L.), and a high accuracy of FVC retrieval was obtained, with rRMSEs of 12%, 6%, and 6%, respectively. Our findings suggest that the proposed method can efficiently retrieve crop FVC from UAV images at a high spatiotemporal domain, which should be a promising tool for precision crop breeding.

Exploring molecular markers and drug candidates for colorectal cancer through comprehensive bioinformatics analysis.

Colorectal cancer (CRC) often has a poor prognosis and identifying useful and novel agents for treating CRC is urgently required. This study aimed to examine molecular markers associated with CRC prognosis and to identify potential drug candidates. The differentially expressed genes (DEGs) of CRC in TCGA were identified. The genes associated with CRC, summarized from NCBI-gene, OMIM, and the DEGs, were used to construct a co-expression network by WGCNA. Moreover, the co-expression genes from modules of interest were used to carry out functional enrichment. A total of 2742 DEGs, including 1674 upregulated and 1068 downregulated genes, were identified. Thirteen co-expression modules were constructed with WGCNA. Brown and blue co-expression modules with significant differences in disease phenotype were found. Functional enrichment analysis showed that genes in the brown module were mainly related to cell cycle, cell proliferation, DNA replication, and RNA transport. The genes in the blue module were mainly associated with fatty acid degradation, sulfur metabolism, PPAR signaling pathway and bile secretion. In addition, both the genes in brown and blue were associated with tumor staging. Some prognostic markers and candidate small molecules drugs for CRC treatment were identified. In conclusion, we revealed molecular biomarker profiles in CRC by systematic bioinformatics analysis, constructed regulatory networks of mRNA, ncRNA and transcriptional regulators (TFs), and identified potential drugs targeting hub proteins and TFs.

A Case of Complete Remission in Proficient Mismatch Repair (pMMR) Advanced Colon Cancer Treated with Sintilimab and XELOX.

Introduction: Colorectal cancer (CRC) is the 3rd most common malignant tumors after breast cancer and lung cancer, accounting for 9.4% of patients. Some patients had distant metastasis at the time of diagnosis without surgery opportunity. It is particularly important to prolong patient survival and improve quality of life. Patient Concerns: A 73-year-old female was admitted with discomfort over 2 months. Enlarged lymph nodes in the left supraclavicular fossa were observed in chest computed tomography (CT). Enhanced abdominal CT showed thickening of the right colon wall with multiple metastatic lymph nodes in the abdomen. Colonoscopy showed ileocecal mass and pathology showed moderately and poorly differentiated adenocarcinoma. Physical examination showed a 2*2 cm lymph node could be touched in the left supraclavicular fossa. The patient was diagnosed advanced colon cancer by the histopathological examination and imaging findings. Actually, it is hardly to resect radically. Intervention: Sintilimab combined with XELOX was initiated. Two period of treatment after initial therapy, laparoscopic radical resection of right colon cancer was performed successfully. Outcomes: After conversion treatment, the enlarged lymph nodes and primary tumor were significantly reduced. The patient was discharged successfully three weeks after surgery. Both specimen and 14 lymph nodes dissected showed no malignancy in pathology. Tumor regression grading (TRG) is 0, which indicate complete regression with no residual tumor cells including lymph nodes. The patient obtained a pathological complete response (pCR). Lessons: The patient achieved a great therapeutic benefit with the above-mentioned chemotherapy in this case. The case provides a potential reference for pMMR CRC patients treating with immune checkpoint inhibitors (ICIs).

Insights into the influence of Fe(III) on the interaction between roxarsone and humic acid using multi-spectroscopic techniques.

The influence of Fe(III) on the interaction between roxarsone (ROX) and humic acid (HA) was investigated by multi-spectroscopic techniques. The fluorescence quenching experiment indicated that the fluorescence intensity of HA-ROX was quenched by Fe(III) through a static quenching process. Synchronous fluorescence spectra provided further information concerning the competitive combination between ROX and Fe(III) for HA. The results of the dialysis equilibrium experiment confirmed the existence of Fe(III) (0.05-0.1 mmol/L) promotes the combination of HA and ROX. Binding mechanisms were further characterized by FTIR spectroscopy, and the carboxyl functional group is involved in the binding process of HA/Fe/ROX. In addition, acidic and neutral conditions are more conducive to the combination of ROX and HA/Fe than alkaline conditions. The above discussion is of great significance in understanding the environmental fate of ROX under the coexistence of Fe(III) and HA.

Dynamic monitoring of biomass of rice under different nitrogen treatments using a lightweight UAV with dual image-frame snapshot cameras.

BACKGROUND: Unmanned aerial vehicle (UAV)-based remote sensing provides a flexible, low-cost, and efficient approach to monitor crop growth status at fine spatial and temporal resolutions, and has a high potential to accelerate breeding process and improve precision field management. METHOD: In this study, we discussed the use of lightweight UAV with dual image-frame snapshot cameras to estimate aboveground biomass (AGB) and panicle biomass (PB) of rice at different growth stages with different nitrogen (N) treatments. The spatial-temporal variations in the typical vegetation indices (VIs) and AGB were first investigated, and the accuracy of crop surface model (CSM) extracted from the Red Green Blue (RGB) images at two different stages were also evaluated. Random forest (RF) model for AGB estimation as well as the PB was then developed. Furthermore, variable importance and sensitivity analysis of UAV variables were performed to study the potential of improving model robustness and prediction accuracies. RESULTS: It was found that the canopy height extracted from the CSM (Hcsm) exhibited a high correlation with the ground-measured canopy height, while it was unsuitable to be independently used for biomass assessment of rice during the entire growth stages. We also observed that several VIs were highly correlated with AGB, and the modified normalized difference spectral index extracted from the multispectral image achieved the highest correlation. RF model with fusing RGB and multispectral image data substantially improved the prediction results of AGB and PB with the prediction of root mean square error (RMSEP) reduced by 8.33-16.00%. The best prediction results for AGB and PB were achieved with the coefficient of determination (r2), the RMSEP and relative RMSE (RRMSE) of 0.90, 0.21 kg/m2 and 14.05%, and 0.68, 0.10 kg/m2 and 12.11%, respectively. In addition, the result confirmed that the sensitivity analysis could simplify the prediction model without reducing the prediction accuracy. CONCLUSION: These findings demonstrate the feasibility of applying lightweight UAV with dual image-frame snapshot cameras for rice biomass estimation, and its potential for high throughput analysis of plant growth-related traits in precision agriculture as well as the advanced breeding program.

[Characterizing the interaction between roxarsone and humic acid by fluorescence quenching experiment].

In this study, the methods of fluorescence spectroscopy and fluorescence quenching titration technique were used to identify the interactions between humic acid (HA) and roxarsone (ROX). Effects of HA concentration, pH and temperature on the bonding strength between HA and ROX were investigated. The results showed that the four fluorescence peaks (E(x)/E(m) = 300 nm/480 nm, 370 nm/480 nm, 420 nm/500 nm, 460 nm/520 nm, marked as peak A, B, C, D respectively) of HA could be quenched by ROX. The extent of decreases in fluorescence intensities of different peaks was different and followed the order of C > B > A > D. The common logarithm of association constants (lg K) between peak A and ROX increased slightly with the increase of HA concentration and were much larger than the bimolecular quenching constant of O2. It was confirmed that the carboxyl groups and the carboxide groups of HA were quenched statically by ROX. The lg K values fluctuated between 3.55 L x mol(-1) and 3.98 L x mol(-1) when pH ranged from 5.00 to 9.00, and the maximum value occurred at pH 6.00. It might be resulted from the fact that pH could change the formation of ROX and conformation of phenolic hydroxyl groups and carboxyl groups in HA. The lg K values decreased and fluctuated between 2.65 L x mol(-1) and 3.89 L x mol(-1) with temperature ranging from 25.0 degrees C to 55.0 degrees C, which further confirmed the static quenching interaction between HA and ROX. Transient-fluorescence spectrum analyses and liner model simulations revealed that single static quenching was the main mechanism between ROX and the functional groups of fluorescence peak A, B, D in HA, and combined dynamic and static quenching was the main mechanism between ROX and the functional groups of peak C in HA.

[Degradation of oxytetracycline with ozonation in acetic acid solvent].

Use acetic acid as the media of ozone degradation of oxytetracycline (OTC), and effects of the initial dosing ratio of ozone/OTC, ozone flow, free radical scavenger, metal ions on the removal rate of OTC were investigated respectively. The results showed that acetic acid had a high ozone stability and solubility. OTC had a high removal rate and degradation rate in acetic acid solution. With the increase of OTC dosage, the removal rate of OTC decreased in acetic acid. Removal rate of OTC was increased distinctly when ozone flow increased properly. It was also observed that free radical scavenger had a significantly negative effect on OTC ozonation degradation in acetic acid. Furthermore the main reactions of OTC ozone oxidation were direct oxidation and indirect oxidation in acetic acid. When Fe3+ and Co2+ were existent in acetic acid, the degradation of OTC was inhibited significantly.