[Transport Characteristics of Phosphorus Sources at the Multi-scale Watershed and the Associated Ecological Effects on Poyang Lake].

In this study, a cascaded watershed system in the Poyang Lake area was selected as the study site, which ranged from the primary tributaries to the lake area (Xiangxi River→Jiazhu River→Ganjiang River→Poyang Lake). The aims of the study were to monitor the P wet deposition and runoff process in the Poyang Lake area and discuss the P transport characteristics at the multi-scale watershed and its impact on phytoplankton community structure in the Poyang Lake. The results showed that the P concentration in the Poyang Lake area exhibited significant seasonal changes. Apart from the Xiangxi River watershed, the concentrations of total phosphorus (TP), dissolved total phosphorus (DTP), and orthophosphate(PO43-) were higher in the low flow period than in the high flow period at other watersheds. There was a significant correlation between TP concentration and diatom density during the high flow period, and between TP concentration and cryptophyta during the low flow period. The order of the amounts of TP and PO43- transport by runoff under different rain intensities is as follows:light rain > moderate rain > heavy rain. There is a significant difference in the deposition flux between the wet season and the dry season with seasonal change, in which the flux during the wet years was about 2.8 times higher than in the dry years. The export flux of P was also shown to be higher in the high flow than in the low flow period. As watershed size increased, the contribution rate of P export did not increase, indicating that P transported at different scales was not the main source of P in each watershed.

[Establishing the Blood Donor Deferral Criterion in TP ELISA Test].

OBJECTIVE: To Establish the shielding threshold value of TP antibody ELISA for unpaid blood donors, so as to shield true positive blood donors from returning to team management. METHODS: The real serological status of 517 samples with anti-TP ELISA reactivity was determined by confirmation test of Treponema pallidum particle agglutination (TPPA). The shielding threshold of TP antibody was preliminarily determined by using 99% specificity of ROC and 95% positive predictive value of percentile method, respectively. 283 TP antibody reactivity specimens routinely tested in our laboratory were selected to determine the applicability of the initial shielding values obtained by the two methods, and finally to determine the shielding threshold values of TP antibody donors. RESULTS: The specific S/CO values of reagent A 99% were 13.33-16.18, that of reagent B 99% was 6.34, that of reagent B 99% was 13.17-19.85, and that of 95% was 6.62. Empirical evidence: 99% specific threshold shielding true positive rates of reagents A and B were 100%, 95% positive expected value shielding true positive rates were 98.4%, 99%. Final determination of 99% specific shielding threshold as a low value of blood donors shielding threshold. The shielding limits of reagent A and B were 13.33 and 13.17. CONCLUSION: The shielding threshold of TP antibody ELISA for blood donors established in this study can help to reduce the number of blood donors returning to team management.

[C and N Transport Flux and Associated Changes of Water Quality Parameters from a Multiscale Subtropical Watershed in the Poyang Lake Area].

In this study, a connected waterflow watershed system in the Poyang Lake area was selected as the study site, which ranged from the primary tributary to the lake area (Xiangxi River Jiazhu River Ganjiang River Poyang Lake). The aims of the study were to monitor different forms of C and N and evaluate the transport flux of C and N, and then, the transport mechanisms of C and N and the variation characteristics of water quality parameters in Poyang Lake were discussed, with the intent of providing a scientific basis for the comprehensive management of watershed health within the Poyang Lake Basin ecosystem. The main results were as follows. ① The concentrations of C and N in the Poyang Lake watershed exhibited significant seasonal changes, wherein the TIC, TOC, and TC concentrations in the Poyang Lake Basin were higher in the wet season than those in the dry season, and the NO3--N and DTN concentrations were higher in the dry season than those in the wet season. The main reason for the increase of TC in the wet season was the increase of TIC. Most of the TN in the wet season was transported by non-dissolved forms of N, while the TN in the dry period mostly was transported by DTN, and the DTN was mostly in the form of NO3--N. ② The C and N transport fluxes in the Poyang Lake watershed also showed significant seasonal variation. The C transport flux of Xiangxi River was lower during the wet season than that during the dry season, and the C transport flux of Jiazhu River and Ganjiang River was higher during the wet season than that during the dry season. The various forms of N transport flux in Xiangxi River, Jiazhu River, and Ganjiang River watershed were higher in the wet season than those in the dry season. There was a very significant positive correlation between the flux and runoff at the 99% confidence level. ③ The COND, TDS, and pH in the Poyang Lake watershed were lower during the wet season than those during the dry season, while the ORP in the wet season was higher than that in the dry season.

[Evaluation of the Performance of Two Kinds of Anti-TP Enzyme-Linked Immunosorbent Assay].

OBJECTIVE: To evaluate the accuracy and precision of 2 kinds of anti-treponema pallidum (anti-TP) ELISA reagents in our laboratory for detecting the anti-TP in voluntary blood donors, so as to provide the data support for use of ELISA reagents after introduction of chemiluminescene immunoassay (CLIA). METHODS: The route detection of anti-TP was performed by using 2 kinds of ELISA reagents, then 546 responsive positive samples detected by anti-TP ELISA were collected, and the infections status of samples confirmed by treponema pallidum particle agglutination (TPPA) test was identified. The confirmed results of responsive samples detected by 2 kinds of anti-TP ELISA reagents were compared, the accuracy of 2 kinds of anti-TP ELISA reagents was analyzed by drawing ROC and comparing area under curve (AUC), and precision of 2 kinds of anti-TP ELISA reagents was compared by statistical analysis of quality control data from 7.1 2016 to 6.30 2017. RESULTS: There were no statistical difference in confirmed positive rate of responsive samples and weak positive samples between 2 kinds of anti-TP ELISA reagents. The responsive samples detected by 2 kinds of anti-TP ELISA reagents accounted for 85.53%(467/546) of all responsive samples, the positive rate confirmed by TPPA test was 82.87%. 44 responsive samples detected by anti-TP ELISA reagent A and 35 responsive samples detected by anti-TP ELISA reagent B were confirmed to be negative by TPPA test. Comparison of AUC showed that the accuracy of 2 kinds of anti-TP ELISA reagents was more high, the difference between 2 reagents was not statistically significant. The coefficient of variation (CV) of anti-TP ELISA reagent A and B was 14.98% and 18.04% respectively, which met the precision requirement of ELISA test. CONCLUSION: The accuracy and precision of 2 kinds of anti-TP ELISA reagents used in our laboratory are similar, and using any one of anti-TP ELISA reagents all can satisfy the requirements of blood screening.

[Characteristics of Nitrogen Transport and Its Source Trace in Loess Plateau's Dam Watershed in Alternating Wet and Dry Seasons:A Case Study of Yangjuangou Watershed].

In this study,we wanted to explore the impacts of N wet deposition on N export and trace the N source by isotopic method through monitoring N wet deposition in Loess Plateau's Dam Watershed in alternating wet and dry seasons,through measuring N wet deposition,rainfall-runoff and base flow process and analyzing concentration change of different forms of N.The results showed that there were 11 rainfall events in the 2015 wet season,in which N wet deposition load reached 814.18 kg and N deposition flux was about 4.26 kg·hm-2,while there were three rainfall events in the 2015 dry season,in which N wet deposition load reached 155.58 kg and N deposition flux was 0.83 kg·hm-2,so it presented a great seasonal variability.By collecting the dynamic process of four rainfall events,we found that,different rainfall intensity had different influence on N export process.The contribution of N wet deposition of four rainfall events to N export in watershed was 16.94 kg.The ratio that N output load of rainfall and river in watershed N output load was 14.45%-64.84%,which showed that the contribution of rainfall to watershed N transport was big.The variation range of δ15 N in Loess Plateau's Dam Watershed was big,which was -0.844‰-12.791‰,and the δ18 O was within the range of 8.166 ‰-15.115 ‰ in the dam watershed.

Effect of treadmill exercise timing on repair of full-thickness defects of articular cartilage by bone-derived mesenchymal stem cells: an experimental investigation in rats.

OBJECTIVE: Current medical practice for the treatment of articular cartilage lesions remains a clinical challenge due to the limited self-repair ability of articular cartilage. Both experimental and clinical researches show that moderate exercise can improve articular cartilage repair process. However, optimal timing of moderate exercise is unclear. We aimed to evaluate the effect of timing of moderate treadmill exercise on repair of full-thickness defects of articular cartilage. DESIGN: Full-thickness cartilage defects were drilled in the patellar groove of bilateral femoral condyles in a total of 40 male SD rats before they were randomly assigned into four even groups. In sedentary control (SED) group, no exercise was given; in 2-week (2W), 4-week (4W) and 8-week groups, moderate treadmill exercise was initiated respectively two, four and eight weeks after operation. Half of the animals were sacrificed at week 10 after operation and half at week 14 after operation. Femoral condyles were harvested for gross observation and histochemical measurement by O'Driscoll scoring system. Collagen type II was detected by immunohistochemistry and mRNA expressions of aggrecan and collagen type II cartilage by RT-PCR. RESULTS: Both 10 and 14 weeks post-operation, the best results were observed in 4W group and the worst results appeared in 2W group. The histochemistry scores and the expressions of collagen type II and aggrecan were significantly higher in 4W group than that in other three groups (P<0.05). CONCLUSIONS: Moderate exercise at a selected timing (approximately 4 weeks) after injury can significantly promote the healing of cartilage defects but may hamper the repair process if performed too early while delayed intervention by moderate exercise may reduce its benefits in repair of the defects.