Characteristics of Gaseous Elemental Mercury in a Suburban Area of Shanghai, China.

To clarify gaseous elemental mercury (GEM) in suburban megacities in the Yangtze River Delta region, China, we observed GEM concentrations from December 2019 to November 2020 in Wujing town, a suburban area of Shanghai. The annual mean GEM concentration was 1.44 ± 0.88 ng m-3. Compared with the historical monitoring data of GEM in Shanghai over the past 10 years, the concentration of GEM showed a decreasing trend. The monthly mean concentrations of GEM showed clear seasonal variation, with higher values in the spring and winter. In spring and winter, typical Hg pollution events were observed, which could be mostly associated with increased local anthropogenic activity and temperature inversion. The results of the correlation analysis of the daily mean GEM concentrations with the AQI and backward trajectory calculations indicate that mercury pollution at monitoring sites can be affected by local, regional and interregional influences.

Seasonal variation in mercury and methylmercury production in vegetated sediment in the Dongtan wetlands of the Yangtze River Estuary, China.

The seasonal cycling of mercury (Hg) in vegetated sediments in the Dongtan wetlands of the Yangtze River Estuary were determined, and microcosm incubation experiments were conducted to evaluate methylmercury (MeHg) production after Hg input. The results showed that the seasonal variations of total Hg and MeHg were very different. The enhanced activity of methylating bacteria could have been the main contributor to the elevated MeHg in the upper surface layer (0-12 cm), which was supported by the higher copy numbers of the hgcA gene in the surface sediment and the MeHg increase during sediment incubation following litterfall addition. Moreover, the incubation results showed that Hg addition greatly increased net MeHg production and that this increase remained under suboxic conditions, suggesting that the potential health risk of Hg in estuarine wetlands could exist for a long time under changing redox conditions.

Effects of varying amounts of different biochars on mercury methylation in paddy soils and methylmercury accumulation in rice (Oryza sativa L.).

There is growing evidence for the potential of biochars (BCs) in remediating mercury-contaminated paddy soils, but the high doses commonly used in laboratory studies discourage BC application in practice. To address these difficulties, we compared the effects of varying amounts of BCs from different sources on the formation of methylmercury (MeHg) in soil and its accumulation in rice through microcosm and pot experiments. The addition of a wide range of added doses (0.3, 0.6, 1, 2, 4 and 5 %, w/w) of BCs derived from different biomass feedstocks (i.e., corn stalk, wheat straw, bamboo, oak and poplar) significantly decreased the fraction of ammonium thiosulfate ((NH4)2S2O3)-extractable MeHg in the soil, although the MeHg contents varied with BC types and doses during soil incubation. However, the extractable MeHg in the soil did not continuously decrease with increasing BC doses, especially at doses of >1 %, resulting in limited further reductions. Moreover, a relatively low application rate (0.3-0.6 %, w/w) of BCs (i.e., corn stalk, wheat straw and bamboo-derived BC), especially of bamboo-derived BCs, significantly decreased the MeHg levels (42-76 %) in rice grains (brown rice). Meanwhile, the extractable soil MeHg decreased (57-85 %), although the MeHg in the soil varied under BC amendment during rice cultivation. These results provide further evidence that applying BC produced from different raw carbon materials (e.g., lignocellulosic biomass) could effectively reduce MeHg accumulation in rice grains, possibly due to MeHg bioavailability reduction in the soil. Our results suggest the possibility of mitigating MeHg accumulation in rice with a low dose of BCs, with great potential for use in remediating moderately contaminated paddy soils.

A systematic review and meta-analysis of nab-paclitaxel mono-chemotherapy for metastatic breast cancer.

BACKGROUND: Although various clinical trials and real-life studies have tried to explore the value of nab-paclitaxel mono-chemotherapy for metastatic breast cancer (MBC), the safety and efficacy of nab-paclitaxel remain unclear which need to be systematically evaluated. METHODS: Electronic searches for prospective clinical trials evaluating nab-paclitaxel monotherapy for MBC were performed. Requisite data were extracted, integrated and analysed from the included studies according to the different study designs using systematic review and meta-analysis. Meta-regression and subgroup analysis were further performed to explore the potential risk factors affecting each individual outcome of interest following nab-paclitaxel monotherapy. RESULTS: Twenty-two studies with 3287 MBC patients were included. A total of 1685 MBC patients received nab-paclitaxel as first-line therapy, 640 patients as further-line therapy, and 962 patients as mixed-line therapy. A total of 1966 MBC patients (60.40%) received nab-paclitaxel weekly, 1190 patients (36.56%) received nab-paclitaxel triweekly and 99 patients (3.04%) received nab-paclitaxel biweekly. The overall incidence rates of all-grade neutropenia, leukopenia, peripheral sensory neuropathy, and fatigue were 52% (95% CI, 38-66%, I2 = 98.97%), 58% (95% CI, 43-73%, I2 = 97.72%), 58% (95% CI, 48-68%, I2 = 97.17%), and 49% (95% CI, 41-56%, I2 = 94.39%), respectively. The overall response rate (ORR) was 40% (95% CI, 35-45%, I2 = 98.97%), and the clinical benefit rate (CBR) was 66% (95% CI, 59-73%, I2 = 98.97%) following nab-paclitaxel monotherapy. The median progression-free survival (PFS) was 7.64 months (95% CI, 6.89-8.40 months, I2 = 92.3%), and the median overall survival (OS) was 24.51 months (95% CI, 21.25-27.78 months, I2 = 92.7%). Treatment line, human epidermal growth factor receptor-2(Her-2)-negative status and dosage were found to be sources of heterogeneity among the included studies. According to the meta-regression and subgroup analysis, grade 3/4 neutropenia occurred less frequently in Her-2-negative patients than in the entire population (P = 0.046). Patients who received first-line nab-paclitaxel monotherapy showed a higher ORR (P = 0.006) and longer PFS (P = 0.045). Efficacy outcomes were not affected by the administration schedule. However, within the same schedule, patients appeared to have a superior ORR (P = 0.044) and longer PFS (P = 0.03) with an increasing dosage of nab-paclitaxel administered. CONCLUSIONS: The benefits brought by nab-paclitaxel mono-chemotherapy in the treatment of MBC are considerable while the harm is generally manageable. Further study and validation are needed to figure out the roles which the dosage, schedule and other factors play actually in nab-paclitaxel chemotherapy.

Comprehensive analysis to identify DLEU2L/TAOK1 axis as a prognostic biomarker in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the deadliest malignant tumors that are harmful to human health. Increasing evidence has underscored the critical role of the competitive endogenous RNA (ceRNA) regulatory networks among various human cancers. However, the complexity and behavior characteristics of the ceRNA network in HCC were still unclear. In this study, we aimed to clarify a phosphatase and tensin homolog (PTEN)-related ceRNA regulatory network and identify potential prognostic markers associated with HCC. The expression profiles of three RNAs (long non-coding RNAs [lncRNAs], microRNAs [miRNAs], and mRNAs) were extracted from The Cancer Genome Atlas (TCGA) database. The DLEU2L-hsa-miR-100-5p/ hsa-miR-99a-5p-TAOK1 ceRNA network related to the prognosis of HCC was obtained by performing bioinformatics analysis. Importantly, we identified the DLEU2L/TAOK1 axis in the ceRNA by using correlation analysis, and it appeared to become a clinical prognostic model by Cox regression analysis. Furthermore, methylation analyses suggested that the abnormal upregulation of the DLEU2L/TAOK1 axis likely resulted from hypomethylation, and immune infiltration analysis showed that the DLEU2L/TAOK1 axis may have an impact on the changes in the tumor immune microenvironment and the development of HCC. In summary, the current study constructing a ceRNA-based DLEU2L/TAOK1 axis might be a novel important prognostic factor associated with the diagnosis and prognosis of HCC.

The predictive factors for postoperative hypoparathyroidism and its severity on the first postoperative day after papillary thyroid carcinoma surgery.

PURPOSE: The purpose of the study was to investigate the predictive factors for hypoparathyroidism and its severity on the first postoperative day (POD1) after total thyroidectomy (TT) with or without central neck dissection (CND) in patients with papillary thyroid carcinoma (PTC). METHODS: From February 2014 to February 2019, 2550 PTC patients were admitted to our department. PTC patients who underwent TT were enrolled in this study. A parathyroid hormone (PTH) level lower than 15 pg/mL on POD1 was defined as hypoparathyroidism, and the severity of hypoparathyroidism was classified into three categories according to the level of PTH on POD1: mild hypoparathyroidism (10 pg/mL ≤ PTH < 15 pg/mL), moderate hypoparathyroidism (5 g/mL ≤ PTH < 10 pg/mL), and severe hypoparathyroidism (PTH < 5 pg/mL). Multiple clinical, pathological and surgical parameters of these two different groups were compared and analyzed to demonstrate the possible causes of hypoparathyroidism. Furthermore, patients who developed postoperative hypoparathyroidism were also included in a subgroup analysis according to the severity of their hypoparathyroidism. The underlying factors affecting different severities of hypoparathyroidism were also illustrated with univariate and multivariate analyses. RESULTS: Ultimately, 690 patients who underwent TT were enrolled in this retrospective study. Through the univariate analysis, different surgeons (P < 0.001), extent of CND (P = 0.009), prophylactic calcium supplementation (PCS) (P < 0.001), preoperative (pre-op) PTH level (P < 0.001), and pre-op phosphorus concentration (P = 0.022) were found to be significantly correlated with postoperative hypoparathyroidism. According to the multivariate analysis, PCS was the only independent high-risk factor for hypoparathyroidism. In the univariate analysis of patient subgroups with different severities of hypoparathyroidism, we demonstrated that the tumor T stage (P = 0.021) and pre-op PTH level (P < 0.001) were associated with the severity of hypoparathyroidism. Furthermore, after the multivariate analysis, hypertension (P < 0.001) and pre-op PTH (P < 0.001) were the two independent predictive factors for the severity of hypoparathyroidism after surgery. CONCLUSIONS: Postoperative PCS could increase the risk for PTC patients developing hypoparathyroidism after thyroid surgery. Patients with a history of hypertension and a relatively high pre-op PTH level may not develop severe hypoparathyroidism after TT with CND.

The effects of low-dose biochar amendments on arsenic accumulation in rice (Oryza sativa L.).

The accumulation of arsenic (As) in rice is one of the food security-related concerns in As-contaminated areas all over the world. Biochar, a potential green and cost-efficient amendment material, affects As mobility/phytoavailability in soil and As accumulation in rice plants to some extent, which remains unclear. Thus, three different biochars derived from rice straw, corn stalks, and bamboo were used to investigate the impacts of biochar amendments on As mobility/phytoavailability in As-contaminated soil using pot and microcosm experiments. The results showed a limited reduction (by 12-16%) in As accumulation in rice grains under a low-dose (0.5%, w/w) biochar amendment, although the three biochars displayed different physicochemical properties. In addition, the biochar amendments did not significantly decrease the As levels in the straw and roots, potentially because of the small changes in As mobility/phytoavailability in amended soil relative to the control. However, As levels in soil solution in the biochar treatment groups increased substantially, by 2.8-6.6 times, with increasing biochar doses (0.5-5%, w/w) in microcosm-based anaerobic incubation experiments, particularly at higher doses (3-5%, w/w). These results could be attributed to the biochar-enhancing activity of As(V)-/Fe(III)-reducing bacteria at a high biochar application rate. Our results suggested that applying high biochar doses may increase the release of As into the soil, resulting in As accumulation in rice plants. Therefore, to mitigate the health risk of As in As-contaminated paddy soils, the remediation technologies from biochar methods should be subjected to more evaluation.

Biochar amendment mitigates the health risks of dietary methylmercury exposure from rice consumption in mercury-contaminated areas.

The accumulation of methylmercury (MeHg) in rice is an important MeHg exposure pathway in humans in several mercury (Hg)-contaminated areas. In this study, the effects of low-dose biochar (BC) amendment (0.3%, w/w) on MeHg mobility/phytoavailability in different Hg-contaminated paddy soils, MeHg accumulation in rice plants and the health risks associated with MeHg-laden rice consumption were investigated. Soils amended with different doses of bamboo-derived BC (0.3, 0.5, and 1%, w/w) were incubated under anoxic conditions in microcosm experiments. In addition, pot experiments were conducted involving rice cultivation with a low BC application rate (0.3%, w/w). We observed that (1) the fraction of extractable MeHg in soils decreased with BC addition in both the microcosm and pot experiments; (2) MeHg concentrations in the rice grains (brown rice) significantly decreased by 56-88% in response to BC amendment, which may be attributed mainly to decreases in MeHg mobility/phytoavailability in the soil; and (3) the hazard quotient (HQ) values for adults and children and fetal intelligence quotient (IQ) decrements associated with MeHg-laden rice consumption were significantly alleviated under BC amendment. Taken together, our findings suggest that a low dose of BC (0.3%, w/w) could have great potential for mitigating the health risks of dietary MeHg exposure from the consumption of rice grown in mercury (Hg)-contaminated areas.

Impacts of biochar and silicate fertilizer on arsenic accumulation in rice (Oryza sativa L.).

Human exposure to arsenic (As) through rice consumption is a global food safety issue, especially in Southeast Asia. To investigate the impacts of biochar amendment (rice husk and smooth cordgrass-derived biochar) and/or silicate fertilizer on As mobility/phytoavailability in soil and on As accumulation in rice, pot and microcosm experiments were conducted. The results showed that both single application of low doses of biochar (0.5%, w/w) and coapplication of biochar with silicate fertilizer decreased As levels in grain (brown rice) by 14-16%, but not in straw and roots. The biodilution of As in grain resulting from increased grain biomass (by 6-21%) could be mainly a response to the decline in grain As levels with biochar and/or silicate fertilizer amendment. However, both applications exerted limited effects to decrease the overall As uptake by rice grain and straw, potentially due to the small changes in As mobility/phytoavailability in amended soil relative to the control, although plant-available silicon (Si) from amendment could potentially inhibit As uptake. Furthermore, microcosm-based anaerobic incubation experiments demonstrated that As levels in soil solution increased (up to 11-14-fold) with increasing doses of biochar amendment (up to 5%, w/w), possibly due to biochar enhancing the reductive dissolution of iron (oxyhydr) oxides via an increase in the total number of iron-reducing bacteria (up to 1.6-3.2-fold). Our findings suggested that a low application rate of biochar may not be a very effective approach for mitigating As accumulation in rice, while a high application rate could enhance the health risk of As in As-contaminated flooded soil.

Occurrence mechanism and coping paths of accidents of highly aggregated tourist crowds based on system dynamics.

The safety of highly aggregated tourist crowds is a challenging and important issue. This paper not only provided a comprehensive analysis of the accidents of highly aggregated tourist crowds but also determined the occurrence mechanism and coping paths. Based on the analysis of multiple cases, we found that the variable status of highly aggregated tourist crowds was the result of the interaction of three main elements: multisource pressure, state mutations and management responses. A series of factors interact and result in accidents, and the lack of a management response or a low-quality management response is the root cause of such accidents. A high-quality management response is a basic safety precaution for highly aggregated tourist crowds. Therefore, forming a virtuous circle of multisource pressure, state mutations and management responses is an effective path for coping with accidents.

Inhibition of Nrf2 promotes the antitumor effect of Pinelliae rhizome in papillary thyroid cancer.

We previously reported that Xiaotan Sanjie (XTSJ) decoction can prevent the progression of gastric cancer in vitro and in vivo. Pinelliae rhizome (PR), one component of XTSJ decoction, has an inhibitory effect on the growth and proliferation of tumor cells. The present study investigated the underlying mechanisms of action of PR. Using the human papillary thyroid cancer cell lines, TPC-1 and BCPAP, we found that XTSJ decoction and PR alone decreased cell viability to a similar extent in both cell lines, whereas treatment with XTJS decoction without PR [PR (-)] had a lesser effect. PR treatment inhibited the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) in a dose-dependent manner. To investigate the role of Nrf2 in the PR-mediated effects of XTSJ, knockdown of Nrf2 in the tumor cell lines using Nrf2 siRNA (siNrf2) was performed and transfected cells were treated with PR. Silencing of Nrf2 amplified the effects on autophagy, cell viability, apoptosis, and colony formation. Similar results were obtained following treatment with the autophagy inhibitor 3-methyladenine (3-MA). Furthermore, treatment with PR, siNrf2, and/or 3-MA inhibited the MAPK pathway, and analysis of the MAPK pathway components confirmed the role of this pathway in the PR-mediated cellular effects. In mice implanted with siNrf2-transfected cells, the effects of PR were amplified. Taken together, these findings indicate that PR is critical for the inhibitory effects of XTSJ decoction on tumor cell viability and that downregulation of Nrf2 promotes the antitumor effects of PR on papillary thyroid cancer cells.

Biochar amendment to further reduce methylmercury accumulation in rice grown in selenium-amended paddy soil.

Methylmercury (MeHg) accumulation in rice is an emerging food safety issue in China and other countries; however, mitigation methods are scarce. Here, the effects of selenium (Se) and multiple applications of Se and biochar on rice MeHg bioaccumulation were investigated using pot and microcosm experiments. We report that Se amendment was still effective in reducing MeHg levels in paddy soil and rice grain after three years of aging. Biochar amendment (0.5% w/w) further decreased grain (brown rice) MeHg levels by 82-87%. The grain MeHg level decrease following the combination of Se and biochar amendment could be partly attributed to inhibition of net MeHg production in soil by Se. In addition, biochar decreased not only net MeHg production but also MeHg bioavailability in the soil, which could be due to organosulfur compounds in the biochar. Our findings suggest that multiple applications of Se and biochar could be a novel remediation strategy to mitigate MeHg accumulation in rice.

[Influence of ENSO Events on the Hydrogen (δ2H) and Oxygen (δ18O) Isotopic Values of Precipitation in Shanghai].

An analysis of the effect of ENSO events with different strengths on the isotopic composition of precipitation is conducted based on test data for 206 precipitation samples collected from January 2012 to February 2017 in Shanghai coupled with the archives for Nanjing, Wuhan, Fuzhou, and Hong Kong from 1961 to 2012 from the Global Network of Isotopes in Precipitation (GNIP) database. During the research periods, the δD and δ18O values in precipitation are lower in summer and autumn but higher in winter and spring. The slope and intercept of the atmospheric precipitation lines during El Niño events are larger than during other times, while anti-temperature, precipitation amount, and vapor pressure effects are more significant than during La Niña events. The δ18O and deuterium excess values (value of d) of rainfall in Shanghai during El Niño and La Niña events of varied strengths have an obvious negative correlation with the oceanic Niño index (ONI), sea surface temperature anomaly (SSTA), and the extreme and cumulative values of ONI. Moreover, ENSO events are closely intertwined with the correlation between δ18O isotopic value in precipitation, ONI, and SSTA.

[Characteristics of Stable Isotope in Precipitation and Its Relationship with ENSO in Shanghai].

A total of 70 precipitation samples were collected from August 2014 to August 2015 in Shanghai and the oxygen and hydrogen isotope of precipitation were analyzed. The relationship between the δ18O and deuterium excess of precipitation and ENSO events was addressed. The results showed that δD and δ18O of precipitation in Shanghai were higher in winter and spring than in summer and fall. The slope of meteoric water line with these data was a little smaller than the global meteoric water line. The main reason could be the unbalanced secondary evaporation in the process of precipitation. The correlation between the δ18O in precipitation and temperature and precipitation varied in different time scales. On a seasonal scale, this work revealed that there was no significant temperature effect in winter, but significant precipitation effect was found in the annual scales, which was obviously affected by the atmospheric circulation. δ18O values and deuterium excess in precipitation recorded the La Niña and El Niño conversion process. During the La Niña event, the δ18O and d values were more negative than those in the El Niño event.

[Magnetic Response of Dust-loaded Leaves in Parks of Shanghai to Atmospheric Heavy Metal Pollution].

To reveal the magnetic response to the atmospheric heavy metal pollution in leaves along urban parks, Camphor leaf samples, widely distributed at urban parks, were collected along the year leading wind direction of Shanghai, by setting two vertical and horizontal sections, using rock magnetic properties and heavy metal contents analysis. The results showed that the magnetic minerals of samples were predominated by ferromagnetic minerals, and both the concentration and grain size of magnetite particles gradually decreased with the winter monsoon direction from the main industrial district. A rigorous cleaning of leaves using ultrasonic agitator washer could remove about 63%-90% of low-field susceptibility values of the leaves, and this strongly indicated that the intensity of magnetic signal was mainly controlled by the PMs accumulated on the leaves surfaces. Moreover, there was a significant linear relationship between heavy metals contents (Fe, Mn, Zn, Cu, Cr, V and Pb) and magnetic parameters (0.442 ≤ R ≤ 0.799, P < 0.05), which suggested that magnetic parameters of urban park leaves could be used as a proxy for atmospheric heavy metal pollution. The results of multivariate statistical analysis showed that the content of magnetic minerals and heavy metal indust-loaded tree leaves was affected by associated pollution of industry and traffic.

Dual-sided composite mesh repair of hiatal hernia: our experience and a review of the Chinese literature.

AIM: To summarize our experience in the application of Crurasoft® for antireflux surgery and hiatal hernia (HH) repair and to introduce the work of Chinese doctors on this topic. METHODS: Twenty-one patients underwent HH repair with Crurasoft® reinforcement. Gastroesophageal reflux disease (GERD) and HH-related symptoms including heartburn, regurgitation, chest pain, dysphagia, and abdominal pain were evaluated preoperatively and 6 mo postoperatively. A patient survey was conducted by phone by one of the authors. Patients were asked about "recurrent reflux or heartburn" and "dysphagia". An internet-based Chinese literature search in this field was also performed. Data extracted from each study included: number of patients treated, hernia size, hiatorrhaphy, antireflux surgery, follow-up period, recurrence rate, and complications (especially dysphagia). RESULTS: There were 8 type I, 10 type II and 3 type III HHs in this group. Mean operative time was 119.29 min (range 80-175 min). Intraoperatively, length and width of the hiatal orifice were measured, (4.33 ± 0.84 and 2.85 ± 0.85 cm, respectively). Thirteen and eight Nissen and Toupet fundoplications were performed, respectively. The intraoperative complication rate was 9.52%. Despite dysphagia, GERD-related symptoms improved significantly compared with those before surgery. The recurrence rate was 0% during the 6-mo follow-up period, and long-term follow-up disclosed a recurrence rate of 4.76% with a mean period of 16.28 mo. Eight patients developed new-onset dysphagia. The Chinese literature review identified 12 papers with 213 patients. The overall recurrence rate was 1.88%. There was no esophageal erosion and the rate of dysphagia ranged from 0% to 24%. CONCLUSION: The use of Crurasoft® mesh for HH repair results in satisfactory symptom control with a low recurrence rate. Postoperative dysphagia continues to be an issue, and requires more research to reduce its incidence.

[Geochemical characteristics and sources of atmospheric particulates in Shanghai during dust storm event].

Atmospheric particulates were sampled from three sampling sites of Putuo, Minhang and Qingpu Districts in Shanghai between Oct. , 2009 and Oct. , 2010. In addition, particulate samples were also collected from Nantong, Zhengzhou, Xi'an, and Beijing city where dust storm dust transported along during spring. Element compositions of atmospheric particulates were determined by XRF and ICP-MS. The concentrations of major and trace elements in atmospheric particulates from Putuo, Minhang and Qingpu Districts were similar, indicating their common source. The UCC standardization distribution map showed that the major element composition of dust storm samples was similar to that of loess in northwestern China, indicating that the dust storm dust was mainly derived from Western desert and partly from local area. The REE partition patterns of dust storm dusts among different cities along dust transport route were similar to each other, as well as to those of northern loess, which indicates that the dust storm samples may have the same material source as loess, which mainly comes from crust material. However, the REE partition patterns of non-dust storm particulates were different among the studied cities, and different from those of loess, which suggests that the non-dust storm samples may be mixed with non-crust source material, which is different from dust storm dust and loess. The major element composition and REE partition pattern are effective indicators for source tracing of dust storm dust.

[Spectroscopic characteristics of different molecular weight dissolved organic matter in water from Yangtze River estuary].

Cross flow ultrafiltration systems and three dimensional fluorescence spectrum were used to investigate the fluorescence characterization of different molecular weight dissolved organic matter in water of wet season and dry season from Yangtze River estuary, in order to find out the sources and influencing factors. The results showed that four types of dissolved organic carbon (DOM) fluorescence peaks were observed in the water: humic-like fluorescence peak A and C, and protein-like fluorescence peak B and D. Fluorescent substances mainly existed in the truly dissolved organic matter (UOM, < 1 kDa), secondly in low and medium molecular weight of colloidal organic matter (1-500 kDa). Protein of DOM in water mainly originated from anthropogenic sources, then from autochthonous sources. Compared to protein, humic acid of DOM in wet season was both terrigenous and autochthonous sources, while in dry season mainly from terrestrial organic matter. In addition, humic acid in UOM was mainly derived from biological decomposition, however, in colloidal organic matter (COM) came from terrestrial organic matter and was affected by resuspension effects. There was linear correlation between fluorescence intensity and environmental parameters. It was revealed that the complex environmental conditions would influence the fluorescent substance of DOM in water from Yangtze River estuary.

Influence of Spartina alterniflora on the mobility of heavy metals in salt marsh sediments of the Yangtze River Estuary, China.

Using bio-disturbed sulphide to trace the mobility and transformation of Cu, Pb, Ni and Zn in the sediments of the Spartina alterniflora-dominated salt marsh in the Yangtze River Estuary, measurements were made of the seasonal variations of acid-volatile sulphide (AVS) and of the simultaneously extracted metals (SEM) in the rhizosphere sediments. Microcosm incubation experiments recreating flooding conditions were conducted to evaluate the effect of AVS and other metal binding phases upon the dynamics of Cu, Pb, Ni and Zn in the salt marsh sediments. The results demonstrate that the ratio values of SEM/AVS have a significant seasonal variation in the rhizosphere sediments and that the anoxic conditions in the sediments were likely enhanced by S. alterniflora during the summer and autumn compared with the anoxic conditions resulting from the native species Phragmites australis and Scirpus mariqueter. The incubation experiments suggest that Fe(III) and Mn(IV/III) (hydr)oxides provide important binding sites for heavy metals under oxic conditions, and sulphide provides important binding sites for the Cu and Pb under anoxic conditions. Our observations indicate that the mobility of heavy metals in the salt marsh sediments is strongly influenced by biogeochemical redox processes and that the invasive S. alterniflora may increase the seasonal fluctuation in heavy metal bioavailability in the salt marsh ecosystem.

Routine central neck dissection in differentiated thyroid carcinoma: a systematic review and meta-analysis.

OBJECTIVE/HYPOTHESIS: The role of central neck dissection (CND) remains controversial in differentiated thyroid cancer (DTC). STUDY DESIGN: Systematic review and meta-analysis. METHODS: A systematic review and meta-analysis focusing on surgical morbidities and locoregional recurrence after total thyroidectomy (TT) with CND versus TT alone was performed. RESULTS: Sixteen trials were analyzed. There was no increased risk of recurrent laryngeal nerve (RLN) injury (temporary or permanent), permanent hypocalcemia, or locoregional recurrence when CND was performed in addition to TT. Postoperative temporary hypocalcemia was more common after TT with CND than after TT alone. CONCLUSIONS: TT alone results in less surgical morbidity in the immediate postoperative period and an identical locoregional recurrence rate compared with TT plus CND.