Estimation of the rice aboveground biomass based on the first derivative spectrum and Boruta algorithm.

Aboveground biomass (AGB) is regarded as a critical variable in monitoring crop growth and yield. The use of hyperspectral remote sensing has emerged as a viable method for the rapid and precise monitoring of AGB. Due to the extensive dimensionality and volume of hyperspectral data, it is crucial to effectively reduce data dimensionality and select sensitive spectral features to enhance the accuracy of rice AGB estimation models. At present, derivative transform and feature selection algorithms have become important means to solve this problem. However, few studies have systematically evaluated the impact of derivative spectrum combined with feature selection algorithm on rice AGB estimation. To this end, at the Xiaogang Village (Chuzhou City, China) Experimental Base in 2020, this study used an ASD FieldSpec handheld 2 ground spectrometer (Analytical Spectroscopy Devices, Boulder, Colorado, USA) to obtain canopy spectral data at the critical growth stage (tillering, jointing, booting, heading, and maturity stages) of rice, and evaluated the performance of the recursive feature elimination (RFE) and Boruta feature selection algorithm through partial least squares regression (PLSR), principal component regression (PCR), support vector machine (SVM) and ridge regression (RR). Moreover, we analyzed the importance of the optimal derivative spectrum. The findings indicate that (1) as the growth stage progresses, the correlation between rice canopy spectrum and AGB shows a trend from high to low, among which the first derivative spectrum (FD) has the strongest correlation with AGB. (2) The number of feature bands selected by the Boruta algorithm is 19~35, which has a good dimensionality reduction effect. (3) The combination of FD-Boruta-PCR (FB-PCR) demonstrated the best performance in estimating rice AGB, with an increase in R² of approximately 10% ~ 20% and a decrease in RMSE of approximately 0.08% ~ 14%. (4) The best estimation stage is the booting stage, with R2 values between 0.60 and 0.74 and RMSE values between 1288.23 and 1554.82 kg/hm2. This study confirms the accuracy of hyperspectral remote sensing in estimating vegetation biomass and further explores the theoretical foundation and future direction for monitoring rice growth dynamics.

Feasibility of Simultaneous Bilateral Endoscopic Surgery in Prone Split-Leg Position for Bilateral Upper Urinary Tract Calculi: A Pilot Study.

INTRODUCTION: We explored the viability of simultaneous bilateral endoscopic surgery (SBES) in the prone split-leg position for managing bilateral calculi. METHODS: We retrospectively reviewed 72 patients who underwent SBES, with procedures involving ureteroscopy (URS) and contralateral percutaneous nephrolithotomy (PNL) simultaneously, in prone split-leg position. RESULTS: Operative times averaged 109.38 ± 30.76 min, with an average hospital stay of 7.79 ± 3.78 days. The bilateral stone-free rate (SFR) was 70.83%, while URS and PNL demonstrated comparable unilateral SFR (83.33% and 79.17%, respectively). Receiver operating characteristics curves for predicting unilateral residual fragments yielded an area under the curve of 0.84 (URS) and 0.81 (PNL) with respective cutoff values of stone diameter of 11.55 mm and 23.52 mm. Fifty-seven (79.17%) and 15 (20.83%) patients encountered grade 0-1/2 complications, with no severe complications (grade 3-5) recorded. No significant changes in blood count or renal function were observed post-SBES. CONCLUSIONS: SBES in the prone split-leg position is a viable option for managing bilateral upper tract urolithiasis. Larger scale studies are needed to further assess safety and efficacy in various positions.

Repetitive Blood Sampling from the Subclavian Vein of Conscious Rat.

Rats are widely used in pharmacokinetics (PK) and toxicokinetic (TK) studies that need to collect a certain amount of blood at specific time points to detect drug exposure. The rat blood sampling method determines the quality of the plasma and further affects the precision of the test results. The subclavian vein blood collection method described in this protocol collects blood samples repeatedly in the conscious state of animals to meet the needs of PK and TK tests. The skills of restraint handling and appropriate procedure of needle incision ensure the success rate of blood collection. It is easy to operate while ensuring the quality of plasma and at the same time catering to animal welfare. However, this method requires skilled operation, and an improper one may cause animal weakness, pain, lameness, and even mortality. The current method has been used in the testing facility for a 4-week oral toxicity study in Sprague Dawley (SD) rats with TK. The maximum amount of blood collected within 24 h did not exceed 20% of the animal's total blood. The animals' body weight was more than 200 g for males and females. The data showed that the animals' bodyweight increased steadily every week, and the clinical observation was normal after repetitive sample collection.

A direct competitive enzyme-linked immunosorbent assay by antibody coated for diethyl phthalate analysis.

A direct competitive enzyme-linked immunosorbent assay (ELISA) has been developed for detection of diethyl phthalate (DEP). Protein-hapten conjugate was synthesized to produce polyclonal antibodies against DEP. Experimental parameters were optimized, including immunoreaction conditions, the dilution ratio of horseradish peroxidase (HRP)-antigen conjugate, time of the antibody coated, effect of pH, and ionic strength. The limit of detection was 0.096ng/ml, and the linear range was 0.1-3500ng/ml with a regression coefficient (R(2)) of 0.9957. Recoveries were between 96.4 and 106.2%. The cross-reactivities of the anti-DEP antibody to six structurally related phthalate esters were less than 9%. The method was successfully applied to the determination of DEP in tap water, river water (Yangtze River), and leachate from plastic drinking bottles. This immunoassay was highly specific, sensitive, rapid, simple, and suitable for DEP monitoring. The results obtained were compared with those obtained using the high-performance liquid chromatography method.

An indirect competitive fluorescence immunoassay for determination of dicyclohexyl phthalate in water samples.

A sensitive and specific indirect competitive fluorescence immunoassays (FIA) has been developed for the quantitative determination of dicyclohexyl phthalate (DCHP) using an antigen-coated plate format. The polyclonal antibodies raised against dicyclohexyl 4-amino phthalate conjugated to bovine serum albumin (BSA) by the amino diazotization linkage method. Antiserum with a sufficiently high titer was generated in rabbits and fluorescein isothiocyanate (FITC) was used as sensitive labels to construct the fluorescence immunoassay (FIA) for measurement of targeted compounds. Under optimized FIA condition, the quantitative working range was from 0.1 to 200 µg L−1 with a limit of detection of 0.05 µg L−1. Other similar phthalate compounds do not interfere significantly in the analysis using this immunoassay technique, and the cross-reactivity rates were less than 10%. Four kinds of water samples (tap water, lake water, river water and leachate) had been detected in this assay, the recovery was 91.3­107.8%. The proposed fluorescence immunoassay turned out to be a powerful tool for monitoring of dicyclohexyl phthalate in water samples at trace level.