Determination of seawater COD spectra using double-loop contraction and sorted frog optimization.

This study develops a novel double-loop contraction and C value sorting selection-based shrinkage frog-leaping algorithm (double-contractive cognitive random field [DC-CRF]) to mitigate the interference of complex salts and ions in seawater on the ultraviolet-visible (UV-Vis) absorbance spectra for chemical oxygen demand (COD) quantification. The key innovations of DC-CRF are introducing variable importance evaluation via C value to guide wavelength selection and accelerate convergence; a double-loop structure integrating random frog (RF) leaping and contraction attenuation to dynamically balance convergence speed and efficiency. Utilizing seawater samples from Jiaozhou Bay, DC-CRF-partial least squares regression (PLSR) reduced the input variables by 97.5% after 1,600 iterations relative to full-spectrum PLSR, RF-PLSR, and CRF-PLSR. It achieved a test R2 of 0.943 and root mean square error of 1.603, markedly improving prediction accuracy and efficiency. This work demonstrates the efficacy of DC-CRF-PLSR in enhancing UV-Vis spectroscopy for rapid COD analysis in intricate seawater matrices, providing an efficient solution for optimizing seawater spectra.

Study on reconstruction and analytical method of seawater radioactive gamma spectrum.

Gamma detector detection technology based on NaI(Tl) scintillation crystal has become a popular research topic and has been applied in the field of marine radioactive environment automatic monitoring because of its advantages of low power consumption, low cost and strong environmental adaptability. However, insufficient energy resolution of the NaI(Tl) detector and great Compton scattering in the low-energy region caused by the abundance of natural radionuclides in seawater hinder the automatic analysis of radionuclides in seawater. This study adopts the combination of theoretical derivation, simulation experiment, water tank test and seawater field test, establishing an effective and feasible spectrum reconstruction method. The measured spectrum in seawater is regarded as the output signal formed by the convolution of the incident spectrum and the detector response function. The acceleration factor p is introduced to construct the Boosted-WNNLS deconvolution algorithm, which is used to iteratively reconstruct the spectrum. The analysis results of the simulation test, water tank test and field test meet the radionuclide analysis speed and accuracy requirements for the in-situ automatic monitoring of seawater radioactivity. The spectrum reconstruction method in this study converts the physical problem of insufficient detection accuracy of spectrometer in the practical application into a mathematical problem of deconvolution solution, restores the original radiation information in seawater, and improves the resolution of the seawater gamma spectrum.

Doctor-led intensive diet education on health-related quality of life in patients with chronic renal failure and hyperphosphatemia.

BACKGROUND: Secondary hyperparathyroidism, renal osteodystrophy, and cardiovascular adverse events can occur if long-term hyperphosphatemia is not corrected, leading to the adverse prognosis of patients with chronic renal failure. Besides the use of phosphorus binders, clinical control measures for hyperphosphatemia in these patients should also incorporate diet control. AIM: To observe doctor-led intensive diet education effects on health-related quality of life in patients with chronic renal failure and hyperphosphatemia. METHODS: We assessed 120 patients with hyperphosphatemia and chronic renal failure on hemodialysis admitted to our hospital (July 2018 to March 2020). The control group (n = 60) was given routine nursing guidance, and the observation group (n = 60) was given doctor-led intensive diet education. The changes in EQ-5D-3L scores, disease-related knowledge, and compliance scores before intervention and 3 and 6 mo after intervention in the two groups were recorded. The levels of serum parathyroid hormone (iPTH), calcium (Ca), phosphorus (P), calcium-phosphorus product (Ca × P), serum creatinine (Scr), and blood urea nitrogen (BUN) before intervention and 3 and 6 mo after intervention in the two groups were assessed along with patient satisfaction. RESULTS: There was no significant difference in blood iPTH, Ca, P, Ca × P, Scr, or BUN levels between the groups before intervention. After 3 and 6 mo of intervention, the blood iPTH, Ca, P, and Ca × P levels in the two groups decreased gradually (P < 0.05), but there were no significant differences in Scr or BUN. The blood iPTH, Ca, P, and Ca × P levels in the observation group were lower than those in the control group (P < 0.05). The satisfaction rate in the observation group after 3 mo was 93.33% and after 6, 90.00%, which was high compared with the 80.00% and 71.67%, respectively, in the control group (P < 0.05). There was no significant difference in EQ-5D-3L score between the two groups before intervention. After 3 and 6 mo of intervention, the visual analogue scale score of the two groups increased gradually (P < 0.05); and the scores of action ability, self-care, daily activities, pain and discomfort, and anxiety and depression decreased gradually (P < 0.05). The overall EQ-5D-3L score in the observation group was better than that in the control group (P < 0.05). There was no significant difference in disease-related knowledge or compliance scores between the groups before intervention. After 3 and 6 mo of intervention, the scores of disease, diet, and medication knowledge and compliance in the two groups increased gradually (P < 0.05). The scores of disease-related knowledge and compliance were higher in the observation group than in the control group (P < 0.05). CONCLUSION: Doctor-led intensive diet education can improve patient satisfaction and the quality of life in patients with chronic renal failure and hyperphosphatemia and promote low-phosphorus diet behavior.

New method for calibrating optical dissolved oxygen sensors in seawater based on an intelligent learning algorithm.

Oxygen sensors based on luminescence quenching are the most commonly used instruments for in situ measurement in seawater due to their accuracy and long-term stability. The calibration method of the sensor is crucial for their accuracy. Conventional methods exhibit some defects, such as strict control of calibration conditions and cumbersome and time-consuming operation. To improve calibration operation and obtain good calibration results, a new calibration method was proposed for the optical dissolved oxygen sensor in seawater based on an intelligent learning algorithm. The sensor to be calibrated and the reference sensor were deployed in the water for synchronous measurements. The calibration system consisted of a temperature-regulated device and a sampling method to improve calibration operation. An intelligent learning algorithm was used to train the calibration data and model the oxygen response of the sensor. Calibration and test results in both laboratory and field showed that the new calibration method is feasible and efficient. It is highly significant for sensor development and in situ measurement in seawater.

Research on minimum detectable activity (MDA) of underwater gamma spectrometer for radioactivity measurement in the marine environment.

To improve the capability of underwater gamma spectrometer to quantify radiation levels slightly above the background radiation in the seawater, the minimum detection activity (MDA) and factors including the background count, detection efficiency and acquisition time were studied using Monte Carlo simulation and field experiments. The simulation results show that the crystal type selected in the spectrometer and its volume, enclosure materials of the spectrometer and its thickness all affect the marine detection efficiency in in-situ measurement, and thus determine MDA of the underwater gamma spectrometer. The acquisition time and the placement depth of the spectrometer in the seawater also affect the MDA in the in-situ measurement. Some research data and suggestions on design and use of underwater gamma spectrometer were presented, which are of guiding significance for the in-situ radioactivity measurement in the marine environment.