A high-sensitivity lab-on-a-chip analyzer for online monitoring of nitrite and nitrate in seawater based on liquid waveguide capillary cells.

Optical detection is an indispensable part of microfluidic systems for nutrient determination in seawater. Coupling total internal reflection capillaries with microfluidic chips is a practical alternative to increase the optical path length for high-sensitivity and a low detection limit in colorimetric assays, which has not been applied in microfluidic devices for seawater nutrients. Here, we present an online microfluidic system which integrated a total internal reflection capillary made of Teflon AF 2400 for the high-sensitivity detection of nitrite and nitrate in seawater. The off-chip capillary lengthens the optical path without changing the internal flow path of the microfluidic chip, enhancing the sensitivity, reducing the detection limit and widening the dynamic range of the system, which significantly improves the performance of the microfluidic system based on wet-chemistry. The detection limit for nitrite is 0.0150 µM using an external 20 cm capillary and 0.0936 µM using an internal 5 cm absorption cell, providing an over 6-fold improvement. Laboratory analysis of surface seawater samples collected from the South China Sea with this system and a one-month online deployment of an autonomous analyzer developed based on this system at a station revealed correlations between the nitrite and nitrate with tide, salinity and chlorophyll over slight variations and narrow ranges, demonstrating the high-sensitivity of this method.

Annual hypoxia causing long-term seawater acidification: Evidence from low-molecular-weight organic acids in the Changjiang Estuary and its adjacent sea area.

In this study, components, concentrations, distribution characteristics, sources of low-molecular-weight organic acids (LMWOAs) and relationships among the annual hypoxia, LMWOAs and seawater acidification were investigated in the Changjiang Estuary and its adjacent sea area in July 2015. Lactic, acetic and formic acids were detected in the seawater samples in the study area, and their total concentrations (ΣLMWOAs) varied from 0 to 262.6 µmol·L-1, with an average value of 39.2 µmol·L-1. In the surface seawater, high concentration areas of ΣLMWOAs occurred in the sea area near the Changjiang Estuary and the Hangzhou Bay, and north of study area. In the sampling stations along transect A6, high concentration areas of ΣLMWOAs appeared in the bottom seawater of nearshore stations and middle seawater of offshore stations. The terrigenous inputs, especially the Changjiang runoff, were the dominant sources for LMWOAs in the sampling period. The consistency of hypoxia areas, high concentration areas of ΣLMWOAs and low pH value areas in winter and summer suggested that annual hypoxia could cause the long-term seawater acidification by producing LMWOAs in the Changjiang Estuary and its adjacent sea area.

Distribution characteristics of low molecular weight organic acids in seawater of the Changjiang Estuary and its adjacent East China Sea: Implications for regional environmental conditions.

In this study, components, concentrations, distribution characteristics and sources of low molecular weight organic acids (LMWOAs) in seawater of the Changjiang Estuary and its adjacent East China Sea were investigated in March 2015. Lactic, acetic and formic acids were identified with their concentration range of 0-16.7, 0-42.7 and 0-6.7 µmol·L-1, respectively. In the surface seawater, high concentrations of LMWOAs appeared in the sea area close to the estuary and along the coast. LMWOAs were important fractions of dissolved organic carbon and acetic acid was dominant component of LMWOAs. Riverine, terrestrial input, phytoplankton and sediment release were important sources for the LMWOAs, and human activities were considered as dominant sources for them in sampling period. The consistency of regions with high concentrations of LMWOAs, eutrophication, seasonal hypoxia and frequent red tide occurrence suggested LMWOAs as potential indicators for evaluating pollution status in coastal areas.

Low-molecular-weight organic acids as important factors impacting seawater acidification: A case study in the Jiaozhou Bay, China.

Low-molecular-weight organic acids (LMWOAs) are ubiquitous water-soluble organic compounds with mass production worldwide, but their influence on coastal marine environments is still lack of consideration. In this study, we select a typical nearshore bay - the Jiaozhou Bay, which is surrounded by Qingdao - a city with modern manufacture, agriculture, aquaculture and service industry, as study area, to investigate the effect of LMWOAs on the nearshore marine environment, and their impact on seawater acidification in coastal areas. During Sep. 2016 to Aug. 2017, we identified three different LMWOAs - acetic acid (AA), formic acid (FA) and lactic acid (LA), with average concentrations of 46.7, 13.9 and 1.4 µmol·L-1 in the seawater of the bay, respectively. Due to the establishment of the Jiaozhou Bay Bridge, the seawater exchange capacity was weakened and thereby the concentration and stocks of AA and FA increased. As weak acids in seawater, the influence of LMWOAs on the seawater acidification of the Jiaozhou Bay was investigated. LMWOAs had significant impact on seawater pH and every 10 µmol·L-1 LMWOA caused an average of 0.02 pH unit decrease. From 2010 to 2017, pH value in the seawater of the bay decreased by about 0.103 and LMWOAs contributed about 83% of its decrease. Besides, two models were established to estimate the influence of LMWOAs on the seawater pH by applying the data set of dissolved inorganic carbon (DIC), total alkalinity (TA) and LMWOAs. The results showed that LMWOAs could enhance acidification of coastal seawater. Considering the importance of LMWOAs in seawater, it is necessary to evaluate their future changes in coastal marine environments. This study initiated a way to identify the source of LMWOAs in seawater and to evaluate their contribution to seawater acidification, and also provided a series of dataset for future study on LMWOAs in coastal environment.

Taohong Siwu decoction for femoral head necrosis: A protocol for systematic review.

BACKGROUNDS: Femoral head necrosis is one of the most common orthopedic diseases which can be diagnosed in all ages with different reasons. Taohong Siwu decoction (TSD) has been widely used in the treatment of femoral head necrosis. However, as far as we know, there is still a lack of supporting evidence regarding the efficacy of TSD for femoral head necrosis. Therefore, this protocol aims to evaluate the effectiveness and safety of TSD for femoral head necrosis. METHODS: Eight electronic databases, including PubMed, the Cochrane Central Register of Controlled Trials, EMBASE, Web of Science, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Technology Periodical database, (Chinese Scientific Journal Database) and Wanfang Database will be searched from the time when the respective databases were established to January 2020. Randomized controlled trials of TSD in the treatment of femoral head necrosis will be collected. After evaluating the quality of methodology and extracting valid data, the final meta-analysis will be carried out with software Revman 5.3. ETHICS AND DISSEMINATION: The results of this systematic review will offer implications of the use of TSD treatment for Femoral Head Necrosis. It uses aggregated published data instead of individual patient data and does not require an ethical board review and approval. The findings will be published in a peer-reviewed journal and disseminated in conference presentations. RESULTS: The results of this study will offer implications of the use of TSD treatment for FHN with this meta-analysis. CONCLUSION: The conclusion of this study will provide recent evidence to assess whether TSD is effective and safe in the treatment of FHN.

[Famous veteran traditional Chinese medicine doctors' medication rules in treating spermatorrhea].

To explore famous veteran traditional Chinese medicine( TCM) doctors' medication rules in treating spermatorrhea based on the medical cases about spermatorrhea collected from Hundred TCM Clinical Doctors of Hundred Years in China and Proven Cases and National Medical Master Test Case. Researchers extracted such data as medicinal and therapies from these cases according to the inclusion and exclusion criteria. Then,Excle 2010,SPSS Clementine 12. 0 and SPSS 22. 0 were adopted respectively for frequency analysis,association rules analysis,cluster analysis and factor analysis. Cluster analysis was carried out by Ochiai algorithm of binary variable data,one of the systematic clustering methods. And principal component analysis was used for factor analysis. Finally,27 medical cases and 41 prescriptions were included in total. The frequency analysis showed that the most common therapy was the astringent therapy( n = 28),which was followed by the tonifying method,tranquilizing method,heat-clearing method,damp-dispelling method and Qiregulating method. The top three kinds of high-frequency traditional Chinese medicines were Poria,Ostreae Concha and Dioscoreae Rhizoma. The association rules analysis found out 11 association rules of medicine pairs,23 association rules of medicine combinations of the three kinds of herbs and 6 association rules of medicine combinations of five kinds of herbs. Among them,the representatives were Rubi Fructus→Fossilia Ossis Mastodi,Rehmanniae Radix Praeparata + Corni Fructus→Dioscoreae Rhizoma,and Pinelliae Rhizoma→Citri Reticulatae Pericarpium,which showed the therapeutic characteristics of astringing,tonifying the kidney and replenishing essence,fortifying the spleen and dispelling dampness. Moreover,7 medicine groups with relevance were extracted from the tree map generated by cluster analysis,including " Phellodendri Chinensis Cortex and Anemarrhenae Rhizoma" and " Angelicae Sinensis Radix,Rehmanniae Radix,Bupleuri Radix and Glycyrrhizae Radix et Rhizoma",which demonstrated the effects of nourishing Yin and purging fire,tonifying and soothing the liver. Besides,totally 12 common factors were obtained according to factor analysis,including 14 drug combinations,like " Amomi Fructus,Anemarrhenae Rhizoma and Phellodendri Chinensis Cortex" and " Nelumbinis Stamen,Moutan Cortex,Poria and Scrophulariae Radix",which indicated the compatibility characteristics of tonifying the spleen and purging fire,dispelling dampness and clearing heat. In conclusion,data mining techniques( including frequency analysis,association rules analysis,cluster analysis and factor analysis) were used to comprehensively analyze the famous veteran TCM doctors' medication rules in treating spermatorrhea,which was helpful for guiding the clinical practice of treating spermatorrhea in TCM.