[Estimation of Cropland Nitrogen Runoff Loss Loads in the Yangtze River Basin Based on the Machine Learning Approaches].

A quantitative understanding of cropland nitrogen (N) runoff loss is critical for developing efficient N pollution control strategies. Using correlation analysis, a structural equation model, variance decomposition, and machine learning methods, this study identified the primary influencing factors of total N (TN) runoff loss from uplands (n=570) and paddy (n=434) fields in the Yangtze River Basin (YRB) and then developed a machine learning-based prediction model to quantify cropland N runoff loss load. The results indicated that runoff depth, soil N content, and fertilizer addition rate were the major influencing factors of TN runoff loss from uplands, whereas TN runoff loss rate from paddy fields was mainly regulated by runoff depth and fertilizer addition rate. Among the four used machine learning methods, the prediction models based on the random forest algorithm presented the highest accuracy (R2=0.65-0.94) for predicting upland and paddy field TN runoff loss rates. The random forest algorithm based model estimated a total cropland TN loss load in the YRB of 0.47 Tg·a-1 (upland:0.25 Tg·a-1; paddy field:0.22 Tg·a-1) in 2013, with 58% of TN runoff loss load derived from the midstream and downstream regions. The models predicted that TN runoff loss loads from croplands in YRB would decrease by 2.4%-9.3% for five scenarios, with higher TN load reductions occurring from scenarios with decreased runoff amounts. To mitigate cropland N nonpoint source pollution in YRB, it is essential to integrate efficient water, fertilizer, and soil nutrient managements as well as to consider the midstream and downstream regions as the high priority area. The machine learning-based modeling method developed in this study overcame the difficulty of identifying the functional relationships between cropland TN loss rate and multiple influencing factors in developing relevant prediction models, providing a reliable method for estimating regional and watershed cropland TN loss load.

Ba3.5Cu7.55In1.15Se9: A Wide-Bandgap Copper Indium Selenide Reveals Strong Luminescence and Third-Harmonic Generation.

A new copper indium selenide, Ba3.5Cu7.55In1.15Se9, was synthesized by the KBr flux reaction at 800 °C. The compound crystallizes with orthorhombic Pnma, a = 46.1700(12) Å, b = 4.26710(10) Å, c = 19.8125(5) Å, and Z = 8. The structural framework mainly consists of four sites of cubane-type defective M4Se3 (M = Cu, Cu/In) units with disordered Cu+/In3+ ions present at the part corner of each unit. The single crystal emits intense photoluminescence at 657 nm with a relative quantum yield (RQY) 0.2 times that of rhodamine 6G powder. The compound belongs to a direct band gap at 1.91 eV, analyzed by Tauc's plot, and the energy is close to the PL position. The Hall effect measurement on a pressed pellet reveals an n-type conductivity with a carrier concentration of 3.358 × 1017 cm-3 and a mobility of 24.331 cm2 V-1 s-1. Furthermore, the compound produces a strong nonlinear third-harmonic generation (THG), with an χS(3) value of 1.3 × 105 pm2/V2 comparable to 1.6 × 105 pm2/V2 for AgGaSe2 measured at 800 nm.

[Estimation of Nitrous Oxide Emission from River System Based on Water Discharge and Dissolved Nitrous Oxide Concentration].

Due to increasing active nitrogen pollution loads, river systems have become an important source of nitrous oxide (N2O) in many areas. Due to the lack of monitoring data in many studies as well as the difficulty in estimating intermediate parameters and expressing temporal-spatial variability in current methods, a high level of uncertainty remains in the estimates of riverine N2O emission quantity. Based on the monthly monitoring efforts conducted for 10 sampling sites across the Yonganxi River system in Zhejiang Province from June 2016 to July 2019, the temporal and spatial dynamics of riverine N2O dissolved concentrations ρ(N2O), N2O fluxes, and their influencing factors were addressed. A multiple regression model was then developed for predicating riverine N2O emission flux to estimate annual N2O emission quantity for the entire river system. The results indicated that observed riverine ρ(N2O) (0.03-2.14 µg·L-1) and the N2O fluxes[1.32-82.79 µg·(m2·h)-1] varied by 1-2 orders of magnitude of temporal-spatial variability. The temporal and spatial variability of ρ(N2O) were mainly influenced by the concentrations of nitrate, ammonia, and dissolved organic carbon, whereas the N2O emission fluxes were mainly affected by river water discharges and ρ(N2O). A multiple regression model that incorporates variables of river water discharge and ρ(N2O) could explain 90% of the variability in riverine N2O emission fluxes and has high accuracy. The model estimated N2O emission quantity from the entire Yonganxi River system of 3.67 t·a-1, with 29% from the main stream and 71% from the tributaries. The IPCC default emission factor method might greatly overestimate and underestimate N2O emission quantities for rivers impacted by low and high pressures of human activities, respectively. This study advances our quantitative understanding of N2O emission for the entire river system and provides a reference method for estimating riverine N2O emission with more accuracy.

[Case-control study on single locking plate and locking plate with suture anchors for the treatment of unstable distal clavicle fractures].

OBJECTIVE: To compare therapeutic effects of single locking plates and locking plates with suture anchors in treating type Neer IIb distal clavicle fractures. METHODS: From January 2013 to January 2015, 40 distal clavicle fractures patients with Neer IIb were treated by retrospectively analyzed and divided into single locking plates (control group) and locking plates with suture anchors(observation group) according to methods of operation. There were 20 patients in control group treated by single locking plates, including 16 males and 4 females aged from 26 to 64 years old with an average of(40.60±12.64) years old; while there were 20 patients in observation group treated by locking plates with suture anchors, including 15 males and 5 females aged from 20 to 57 years old with an average of(37.30±10.56) years old. Length of incisions, operation time, blood loss, hospital stays, fracture healing observed by X-ray, position of internal fixation, and changes of coracoclavicular distance were compared, Constant-Murley score was used to evaluate shoulder joint function. RESULTS: All patients were followed up from 22 to 42 months with an average of (30.08±6.72) months. There was no statistical significance in length of incisions, operation time, blood loss, hospital stays and fracture healing time (P>0.05). Constant-Murley score in control group was 83.10±5.81, and lower than that of observation group (92.30±6.05)(P<0.05) at final following-up. Coracoclavicular distance in control group (11.22±3.85) mm, was longer than that of observation group (8.71±2.14) mm(P<0.05). CONCLUSIONS: Compared with locking plates, locking plates with suture anchors for type Neer IIb distal clavicle fractures has better shoulder joint, shorter coracoclavicular distance. It showed coracoclavicular ligament is an effectiveness method for treating Neer IIb distal clavicle fractures.

Experimental infections of mosquitoes with severe fever with thrombocytopenia syndrome virus.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is a newly identified emerging infectious disease, which is caused by a novel bunyavirus (termed SFTSV) in Asia. Although mosquitoes have not been identified as the primary vectors, as revealed by epidemiological surveys, their role in transmitting this SFTSV as a suspicious vector has not been validated. FINDINGS: In this study, we conducted experimental infections of mosquitoes with SFTSV to examine the role of mosquitoes in the transmission of the virus. We did not detect viral replication in Culex pipiens pallens, Aedes aegyptis and Anopheles sinensis as revealed by qRT-PCR assay. In addition, we failed to isolate SFTSV from the Vero cells cultured with suspensions of SFTSV-infected mosquitoes. CONCLUSION: The results of the present study demonstrate little possibility that mosquitoes act as vectors for the emerging pathogen SFTSV.

Relationship between Iodine Content in Household Iodized Salt and Thyroid Volume Distribution in Children.

OBJECTIVE: To assess the effect of different levels of salt iodine content on thyroid volume (ThV) distribution using data from the 1999, 2011, and 2014 Chinese national iodine deficiency disorder (IDD) surveys. METHODS: Probability proportion to size (PPS) sampling method was used to obtain a representative national sample of 34,547, 38,932, and 47,188 Chinese children aged 8-10 years in 1999, 2011, and 2014 Chinese national IDD surveys, respectively. The iodine content in household iodized salt and urinary iodine concentration were measured and thyroid ultrasound examination was performed. The data were analyzed by SAS software using histograms and box plots. The skewness and kurtosis were calculated for testing the normality of ThV. RESULTS: The median iodine content in household iodized salt dropped from 42.30 mg/kg in 1999 to 25.00 mg/kg in 2014. The median urinary iodine concentration of children aged 8-10 years decreased from 306.0 µg/L in 1999 to 197.9 µg/L in 2014. The median and interquartile range (IQR) of ThV in 1999, 2011, and 2014 surveys were 3.44 mL and 1.50 mL, 2.60 mL and 1.37 mL, 2.63 mL and 1.25 mL, respectively. The skewness and kurtosis of ThV distribution in 1999, 2011, and 2014 surveys were 1.34 and 5.84, 0.98 and 3.54, 1.27 and 5.49, respectively. CONCLUSION: With reduced salt iodization levels, the median urinary iodine concentration and median ThV of children decreased significantly, and the symmetry of the ThV distribution improved.

Multienzymatic cascade synthesis of fucosyloligosaccharide via a two-step fermentation strategy in Escherichia coli.

OBJECTIVES: To achieve multienzymatic cascade synthesis of fucosyl oligosaccharide from D-mannose by two-step fermentation pathway in Escherichia coli. RESULTS: E. coli BL21(DE3) harboring pET-22b(+) vectors with six genes, i.e., glucokinase (Glk), phosphomannomutase (ManB), mannose-1-phosphate guanylytransferase (ManC), GDP-mannose 4,6-dehydratase (Gmd), GDP-4-keto-6-deoxy-D-mannose-3,5-epimerase/4-reductase (WcaG), and α-1,2-fucosyltransferase (Fuct) were co-inoculated, and the multienzyme synthetic pathway was constructed to produce fucosyloligosaccharide using D-mannose as substrate. The product, analyzed by LC/MS, fucosyloligosaccharide was formed under the catalysis of Fuct using GDP-fucose as donor substrate and lactose as acceptor substrate. Fucosyloligosaccharides reached 22 mM by a two-step fermentation compared to 3.7 mM with a one-pot fermentation. CONCLUSIONS: Fucosyloligosaccharide was produced by a two-step fermentation to avoid the inhibitory effect of GDP-fucose on Gmd. Two-step fermentation is a rational synthetic pathway for accumulating fucosyloligosaccharide.

[Relaxation laryngoplasty in the management of mutational falsetto].

OBJECTIVE: To observe the result of relaxation laryngoplasty in the management of mutational falsetto. METHODS: The thyroplasty type 3 was applied and improved (the saturation was improved in the traditional operation, which the thyroid cartilage stick was cut off and overlapped without saturation in improved group 1, while the thyroid cartilage stick was not cut off and overlapped inward without saturation in improved group 2) in 30 adult patients who failed in voice modification. Preoperative and postoperative fundamental frequency (F0), normalised noise energy (NNE) and reading essay were compared. RESULTS: F0 dropped significantly from the preoperative mean of (276.5 +/- 46.7) Hz [see equation in text] to the postoperative mean of (127.5 +/- 32.1) Hz in one month (t = 13.68, P < 0.001), while the NNE dropped significantly from the preoperative mean of (-10.9 +/- 4.9) dB to the postoperative mean of (-7.7 +/- 4.1) dB, the difference was statistically significant (t = 4.07, P < 0.001). In the three kinds of operation, the postoperative F0 in the improved group 1 dropped most significantly (compared with traditional operation group t = 2.64, P< 0.05). The postoperative NNE in the improved group 2 increased minimally. The difference was not significant statistically compared with other two kinds of operations (P > 0.05). The pitch dropped in all cases during reading aloud and conversation, while the voice breaks was disappeared. CONCLUSIONS: Relaxation laryngoplasty was proved to be an efficient procedure in the surgical management of mutational falsetto.It was a preferable option for the patients who failed in voice modification. The improved operation profited to recover natural intonation and lighten the hoarseness due to glottic incompetence.

[The study of tissue-engineering bone for repair of segmental bone defects].

OBJECTIVE: To investigate the effect of tissue-engineering bone on repair of segmental bone defects. METHODS: Segmental bone defect of 21mm was created at sheep left metatarsus, which was then implanted with tissue-engineering bone (the experimental group) and pure porous beta-TCP (the control group) respectively. The bone defect in the blank group was left without treatment. After the sheep were sacrificed at the 1st, 3rd, or 6th month postoperatively, the samples were taken and examined by radiological, histological and biomechanical methods as well as scanning electron microscopy. The sheep in the blank group were sacrificed at the 6th month postoperatively. RESULTS: The osteoid tissue, woven bone and lamellar bone in the defect of the experimental group occurred earlier than in the control group. The new bone formed directly without through a cartilaginous intermediate in the experimental group, while the defect was repaired in a "creep substitution" way in the control group. At the 6th month, radiological and biomechanical tests revealed nearly complete repair of the bone defect of the experimental group, partial repair in the control group and non-healing in the blank group. CONCLUSIONS: Tissue-engineering bone can repair bone defect, accelerating healing and without "creep substitution", which is a good option in repair of critical segmental bone defects. This study set up a basis for clinical applications in the future.