Silicon fractionations in coastal wetland sediments: Implications for biogeochemical silicon cycling

Coastal wetland sediment is important reservoir for silicon (Si), and plays an essential role in controlling its biogeochemical cycling. However, little is known about Si fractionations and the associated factors driving their transformations in coastal wetland sediments. In this study, we applied an optimized sequential Si extraction method to separate six sub-fractions of non-crystalline Si (Sinoncry) in sediments from two coastal wetlands, including Si in dissolved silicate (Sidis), Si in the adsorbed silicate (Siad), Si bound to organic matter (Siorg), Si occluded in pedogenic oxides and hydroxides (Siocc), Si in biogenic amorphous silica (Siba), and Si in pedogenic amorphous silica (Sipa). The results showed that the highest proportion of Si in the Sinoncry fraction was Siba (up to 6.6 % of total Si (Sitot)), followed by the Sipa (up to 1.8 % of Sitot). The smallest proportion of Si was found in the Sidis and Siad fractions with the sum of both being <0.1 % of the Sitot. We found a lower Siocc content (188 ± 96.1 mg kg-1) when compared to terrestrial soils. The Sidis was at the center of the inter-transformation among Si fractions, regulating the biogeochemical Si cycling of coastal wetland sediments. Redundancy analysis (RDA) combined with Pearson's correlations further showed that the basic biogenic elements (total organic carbon and total nitrogen), pH, and sediment salinity collectively controlled the Si fractionations in coastal wetland sediments. Our research optimizes sediment Si fractionation procedure and provides insights into the role of sedimentary Si fractions in controlling Si dynamics and knowledge for unraveling the biogeochemical Si cycling in coastal ecosystems.

Wastewater inputs reduce the CO2 uptake by coastal oceans

Every year a large quantity of wastewater is generated worldwide, but its influence on the carbon dioxide (CO2) uptake by coastal oceans is not well understood. Here, sea surface CO2 partial pressure (pCO2) and air-sea CO2 flux were examined in the Jiaozhou Bay (JZB), a temperate coastal bay strongly disturbed by wastewater inputs. Monthly surveys from April 2014 through March 2015 showed that surface pCO2 in the JZB substantially varied both temporally and spatially between 163 μatm and 1222 μatm, with an annual average of 573 μatm. During April-December, surface pCO2 was oversaturated with respect to the atmosphere, with high values exceeding 1000 μatm in the northeastern part of the bay, where seawater salinity was low mainly due to the inputs of wastewater with salinity close to zero. During January-March, surface pCO2 was undersaturated, with the lowest value of <200 μatm also mainly in the northeastern part because of low water temperature and strong biological production. Over an annual cycle, apparently sea surface temperature dominated the monthly variation of surface pCO2 in this shallow bay, while wastewater inputs and related biological production/respiration dominated its spatial variability. Overall, the JZB was a net CO2 source to the atmosphere, emitting 9.6 ± 10.8 mmol C m-2 d-1, unlike its adjacent western part of the Yellow Sea and most of the temperate coastal oceans which are a net CO2 sink. This was possibly associated with wastewater inputs that cause high sea surface pCO2 via direct inputs of CO2 and degradation of organic matter. Thus, from this viewpoint reducing wastewater discharge or lowering CO2 levels in discharged wastewater may be important paths to enhancing the CO2 uptake by coastal oceans in the future.

Preliminary assessment of carbonic acid dissociation constants: Insights from observations in China's east coastal oceans

Based on observations in China's east coastal oceans, we conducted a preliminary assessment of 16 sets of carbonic acid dissociation constants (K1* and K2*) by comparing spectrophotometrically measured pH values at 25 °C with those calculated from total alkalinity and dissolved inorganic carbon. We obtained that K1* and K2* often performed differently within different salinity ranges, and that the constants of Millero et al. (2002) (M02) demonstrated the best performance for the salinity range of 24-35. In contrast, the often recommended constants of Mehrbach et al. (1973) refit by Dickson and Millero (1987) (DM87-M) and Lucker et al. (2000) (L00) would underestimate pH at salinities of 24-30. This was mainly associated with the higher product of K1* and K2* by DM87-M and L00 than by M02 at this salinity range. Also, we found almost no differences between pH values calculated with DM87-M and L00.

The Effect of PARP Inhibitor Radiosensitization on the mRNA Translational Regulation of T Cell Chemokines

PURPOSE/OBJECTIVE(S)

Immunotherapy has modestly improved survival for small cell lung cancer (SCLC) patients. Low response rate and rapid disease progression remain an intractable challenge. One of the factors that contribute to immunotherapy resistance is the lack of cytotoxic T cell infiltration. The expression of chemoattractant cytokines, like CCL5 and CXCL10, are essential for T cell infiltration. The control of chemokine expression is not fully understood, but both transcriptional and translational control pathways could play a major role. Previous studies have shown a correlation between DNA damage and chemokine expression and that PARP inhibitors (PARPi) are radiosensitizers for SCLC that increases DNA damage. The objectives of this study were to define this potential PARPi immunogenic radiosensitizing relationship.

MATERIALS/METHODS

We identified doses of olaparib+ radiation treatment (RT) that conferred radiosensitization in SCLC cell-lines by cell viability and/or clonogenic assays. Olaparib+RT induced CCL5 and CXCL10 mRNA expression was measured by qPCR across SCLC cell-lines. Protein level of chemokines was assessed by immunoblotting. SBC5 cells were treated with olaparib+RT and submitted for RNA sequencing analysis. Genes with adjusted p value<0.05 were considered significant. Protein level changes and target gene knock-out (KO) were confirmed by immunoblotting. Chemokine CXCL10 mRNA and protein level in wildtype (WT) and KO cells were measured by qPCR and western blot, respectively. A mRNA decay assay and dual-luciferase reporter assay was used to identify the region of CXCL10 mRNA that confers mRNA stability control. In vivo anti-tumor efficacy and tumor T cell infiltration studies were done in B6129F mice bearing KP1 tumors. And the T cell infiltration was measured by immune profiling.

RESULTS

In vitro, olaparib+RT significantly increased CXCL10 mRNA in all four SCLC subtype cell-lines in comparison to vehicle control. Consistently, the increase of CXCL10 protein levels (3-fold) was observed in SBC5 cells. By RNA-Seq, a top-ranking translational repressor was EIF4E2 (4EHP) mRNA. The downregulation of EIF4E2 protein by olaparib+RT was validated in four SCLC subtypes by western blot. EIF4E2 KO in HEK293 and SBC5 cells increased CXCL10 mRNA and protein level. By mRNA decay assay and western blot, the absence of EIF4E2 stabilized CXCL10 mRNA and increased CXCL10 protein levels. The dual-luciferase assay demonstrated EIF4E2 destabilizes CXCL10 mRNA via the 3'UTR of CXCL10. In vivo, immune profiling showed olaparib+RT significantly increased the total T cell and CD8+ T cell infiltration. Finally, anti-PD-L1 inhibition potentiated olaparib + IR to improve tumor control in KP1 allograft.

CONCLUSION

Our study demonstrated olaparib + RT increases CXCL10 protein levels through downregulating EIF4E2 to subsequently increase T cell infiltration. Olaparib + RT enhanced anti-PD-L1 immunotherapy efficacy and has therapeutic potential as an immunogenic radiosensitizer.

Trends in nutrients in the Changjiang River

Better documentation and understanding of long-term temporal dynamics of nutrients in watersheds are necessary to support effective water quality management. We examined the hypothesis that the recent management of fertilizer use and pollution control in the Changjiang River Basin could govern the fluxes of nutrients from the river to the sea. Results based on historical data since 1962 and surveys in recent years show that concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) in the mid- and downstream reaches were higher than those in the upper reaches due to intensive anthropogenic activities, while dissolved silicate (DSi) was distributed evenly from the up- to downstream reaches. Fluxes of DIN and DIP increased rapidly, and DSi declined during the 1962-1980 and 1980-2000. After the 2000s, concentrations and fluxes of DIN and DSi remained almost unchanged; those of DIP remained stable until the 2010s and slightly decreased afterward. The decline in fertilizer use explains 45 % of the variance in the decline of DIP flux, followed by pollution control, groundwater and water discharge. As a result, the molar ratio of DIN:DIP, DSi:DIP and ammonia:nitrate varied largely during 1962-2020, and the excess DIN relative to DIP and DSi lead to increased limitations of silicon and phosphorus. A turning point probably occurred for nutrient fluxes in the Changjiang River in the 2010s, with the pattern of DIN from continuous increase to stability and DIP from increase to decrease. This decline in phosphorus in the Changjiang River has many similarities with the rivers worldwide. The continued basin nutrient management is likely to have a major influence on river nutrient delivery and therefore may control coastal nutrient budget and ecosystem stability.

Hindcasting harmful algal bloom risk due to land-based nutrient pollution in the Eastern Chinese coastal seas

Harmful algal blooms (HABs) have been increasing in frequency, areal extent and duration due to the large increase in nutrient inputs from land-based sources to coastal seas, and cause significant economic losses. In this study, we used the "watershed-coast-continuum" concept to explore the effects of land-based nutrient pollution on HAB development in the Eastern Chinese coastal seas (ECCS). Results from the coupling of a watershed nutrient model and a coast hydrodynamic-biogeochemical model show that between the 1980s and 2000s, the risk of diatom blooms and dinoflagellate blooms increased by 158% and 127%, respectively. The spatial expansion of HAB risk caused by dinoflagellates is larger than that of diatoms. The simulated suitability of the habitat for bloom of Aureococcus anophagefferens, a pico-plankton of non-diatom or dinoflagellate, in the Bohai Sea is consistent with observations spatially and temporally. To halt further nutrient accumulation in the ECCS, reductions of dissolved inorganic nitrogen (DIN) (16%) and dissolved inorganic phosphorus (DIP) (33%) loading are required. To improve the situation of distorted DIN:DIP ratios, even larger reductions of DIN are required, especially in the Bohai Sea. Our approach is a feasible way to predict the risk of HABs under the pressure of increasing anthropogenic nutrient pollution in coastal waters.

Specific PhytOC fractions in rice straw and consequent implications for potential of phytolith carbon sequestration in global paddy fields

Phytoliths are silica biomineralization products within plants and have been considered as a promising material to sequester carbon (C). However, there is considerable uncertainty and controversy regarding the C content in phytoliths due to the lack of detailed information on variation of C under different extraction procedures. Herein, we established a series of batch digestion experimental procedures coupled with analyses of phytoliths using Scanning Electron Microscopy and Energy-Dispersive X-ray Spectroscopy to divide phytoliths into three fractions. We then reported an approach for standardizing across hundreds of values found in the literature. Combining this standardized approach with C contents in phytoliths extracted from different digestion degrees, we revaluated the potential production rates of phytolith-occluded carbon (PhytOC) input globally in rice paddy fields. The results showed that the C content in recovered phytoliths exhibited a significantly fitting exponential relationship (p < 0.01) with digestion degrees and decreased from 30 to 75 g kg^-1 under moderate digestion to <5 g kg^-1 under over digestion. On a global scale, the production of total PhytOC in the world paddy fields reached up to (2.71 ± 0.85) × 10⁶ t year^-1. Therein, the contribution of sub-stable PhytOC fraction, stable PhytOC fraction, and recalcitrant PhytOC fraction was 63 %, 28 %, and 9 %, respectively. Our results imply that the estimation of phytolith C sequestration potential across the global paddy fields is associated with specific PhytOC fractions. Therefore, further determining the storage time limits of these specific PhytOC fractions after returning to soil will be vital for predicting terrestrial biogeochemical C sequestration potentials of phytoliths.

Storage, patterns and influencing factors for soil organic carbon in coastal wetlands of China

Soil organic carbon (SOC) in coastal wetlands, also known as "blue C," is an essential component of the global C cycles. To gain a detailed insight into blue C storage and controlling factors, we studied 142 sites across ca. 5000 km of coastal wetlands, covering temperate, subtropical, and tropical climates in China. The wetlands represented six vegetation types (Phragmites australis, mixed of P. australis and Suaeda, single Suaeda, Spartina alterniflora, mangrove [Kandelia obovata and Avicennia marina], tidal flat) and three vegetation types invaded by S. alterniflora (P. australis, K. obovata, A. marina). Our results revealed large spatial heterogeneity in SOC density of the top 1-m ranging 40-200 Mg C ha^-1 , with higher values in mid-latitude regions (25-30° N) compared with those in both low- (20°N) and high-latitude (38-40°N) regions. Vegetation type influenced SOC density, with P. australis and S. alterniflora having the largest SOC density, followed by mangrove, mixed P. australis and Suaeda, single Suaeda and tidal flat. SOC density increased by 6.25 Mg ha^-1 following S. alterniflora invasion into P. australis community but decreased by 28.56 and 8.17 Mg ha^-1 following invasion into K. obovata and A. marina communities. Based on field measurements and published literature, we calculated a total inventory of 57 × 10⁶  Mg C in the top 1-m soil across China's coastal wetlands. Edaphic variables controlled SOC content, with soil chemical properties explaining the largest variance in SOC content. Climate did not control SOC content but had a strong interactive effect with edaphic variables. Plant biomass and quality traits were a minor contributor in regulating SOC content, highlighting the importance of quantity and quality of OC inputs and the balance between production and degradation within the coastal wetlands. These findings provide new insights into blue C stabilization mechanisms and sequestration capacity in coastal wetlands.

Decadal change in dissolved silicate concentration and flux in the Changjiang (Yangtze) River

Silicon (Si) plays an essential role in the biogeochemistry of rivers. This study explored how damming, eutrophication and climate change alters the abundance and flux of DSi in the Changjiang (Yangtze) River based on long-term observations. The results showed that Three Gorges Reservoir (TGR) could enhance DSi transfer only during low-flow time period, and a downstream DSi retention effect by the TGR was found between the Yichang and Jianli stations in the Changjiang River. This resulted in a DSi loss during March and April in the mainstream from Three Gorges Dam (TGD) to Jianli but a DSi addition during July and October along the main channel of the Changjiang River. Long-term data showed a sharp decrease in DSi abundance at the Cuntan, Hankou and Datong stations between the 1960s and 1980s, but a slight increase in DSi between the 1990s and 2010s at these stations. The decrease in DSi during the 1960s -1980s was primarily the result of a decrease trend of silicate weathering, while a slight DSi increase compared to the temperature/DSi relation after the 1990s was largely due to increased DSi retention in the basin by damming and eutrophication. Eutrophication and damming increase DSi trapping in both the river channel and reservoir systems in the low-flow period and thus enhance the nutrient distortion in the coastal ocean.

Effects of emerging contaminants and heavy metals on variation in bacterial communities in estuarine sediments

Emerging contaminants (ECs) and heavy metals (HMs) are universally present together in estuarine sediments; despite this, their effects on microbial communities have been widely studied separately, rather than in consort. In this study, the combined effects of ECs and HMs on microbial communities were investigated in sediments from 11 major river estuaries around the Bohai Sea, China. Proteobacteria, Bacteroidetes, and Firmicutes were the dominant phyla in the sediments. Using Shannon indices, total phosphorus and total organic carbon were shown to affect microbial community structure. Redundancy analysis of microbial variation implicated Cd and As as the greatest pollutants, followed by Mn, Fe, Zn and Cu; no impacts from galaxolide (HHCB) and tonalide (AHTN) were found. Correlation analysis demonstrated that the concentration of ECs increased the abundance of certain bacteria (e.g., Haliangium, Altererythrobacter, Gaiella and Erythrobacter), and therefore these can be used as potential contamination indicators. Shannon indices and Chao1 indices showed that there were differences in the richness and diversity of bacterial communities in the sediments of 11 rivers. The principal coordinate analysis displayed higher similarity of bacterial community composition in estuarine sediments in Liaoning province than other regions. The results can be used to predict changes in estuary ecosystems to maintain their ecological balance and health.

Biopsy-tract haemocoagulase injection reduces major complications after CT-guided percutaneous transthoracic lung biopsy

AIM

To determine whether the injection of haemocoagulase into the biopsy tract can reduce pneumothorax and pulmonary haemorrhage after computed tomography (CT)-guided percutaneous transthoracic lung biopsy (PTLB).

MATERIALS AND METHODS

A retrospective study was performed involving patients with undiagnosed pulmonary lesions scheduled for PTLB between January 2020 and March 2021. Patients were assigned to the haemocoagulase group or the non-haemocoagulase group. After CT-guided biopsies were performed with a 17 G coaxial system, patients in the haemocoagulase group received a haemocoagulase injection (0.2-0.5 units) in the biopsy tract as the sheath was withdrawn. Postoperative image studies were performed to evaluate complications, including pneumothorax and pulmonary haemorrhage. Factors, including the patient's position, lesion location, and pathological results, were evaluated to determine their associations with the complications.

RESULTS

A total of 100 patients were included, with 44 men and a mean age of 53 years old. The overall incidences of pneumothorax and pulmonary haemorrhage were 15% and 13%, respectively. The incidences of pneumothorax and pulmonary haemorrhage were statistically significantly lower in the haemocoagulase group (8% and 6%, respectively) than in the non-haemocoagulase group (22% and 20%, respectively; p=0.04 and 0.03, respectively). There was no statistically significant difference in haemoptysis between the haemocoagulase (6%) and non-haemocoagulase (2%) groups (p=0.23). There were also no statistically significant associations of pneumothorax or pulmonary haemorrhage with the patients' positions, lesion location, or pathological results.

CONCLUSION

Biopsy tract haemocoagulase injection reduced the incidences of postoperative pneumothorax and pulmonary haemorrhage after PTLB.

Occurrence and distribution of cyclic-alkane-consuming psychrophilic bacteria in the Yellow Sea and East China Sea

Cyclic alkanes (c-alkanes) are toxic compounds that are abundant in subsurface oil reservoirs and spilled condensate; hence, their environmental risk is significant. Although numerous studies have focused on the decomposition of other compound classes, e.g., acyclic alkanes and aromatic hydrocarbons, very little is known about the biodegradation of c-alkanes in the marine environment. Here, we enriched methylcyclohexane (MCH)-degrading bacteria derived from the cold bottom water (10-20 °C) of China's marginal seas in summer and characterized the changes to the bacterial community using high-throughput amplicon sequencing. MCH-consuming bacteria failed to grow from the warmer surface water (25-29 °C) in the same geographic sites and seasons. Notably, MCH-consuming communities derived from the cold bottom water in the Yellow Sea exhibit distinct structures compared to the other treatments. Furthermore, almost all dominant species in this setting appear to be specifically adapted to deeper cold water as indicated by significantly negative correlations to temperature (P < 0.01). From these results, we proposed that the biodegradation of MCH is effectively limited to the colder waters (10-20 °C) of China's marginal seas, with uncultured psychrophiles acting as the key taxa for MCH decomposition. Overall, this study indicates key functions for uncultivated microbes in the marine environment.

Inventory of riverine dissolved organic carbon in the Bohai Rim

Riverine carbon (C) composition and export are closely related to changes in the coastal environment and climate. Excessive C inputs from rivers to seas and their subsequent decomposition could result in harmful algal blooms and ecosystem degradation in the coastal sea. In this study, we explored the C transportation and composition in the 24 major rivers of the Bohai Sea (BS) Rim based on the investigation of dissolved organic carbon (DOC), carbon stable isotopes (δ¹³C_DOC) and chromophoric dissolved organic matter (CDOM). The results showed that the riverine DOC concentrations were high (10.6 ± 6.04 mg/L) in the BS Rim compared with the DOC levels in the main rivers in Eastern China (4.98 ± 2.45 mg/L). The δ¹³C_DOC ranged from -28.29‰ to -25.32‰ in the rivers of the BS Rim, suggesting that the DOC mainly originated from riverine plankton, soil organic matter mainly induced by C3 plants, and sewage. The excitation-emission matrix fluorescence spectroscopy of the CDOM indicated that a soluble, microbial by product-like material accounted for the largest proportion (approximately 40%) of CDOM in these rivers and that CDOM mainly originated from autochthonous riverine sources with high protein-like components. The rivers in the BS Rim transported approximately 0.55 Tg C of DOC to the BS each year, with more than 70% of reactive C based on the CDOM composition. The DOC yields in terms of unit drainage area transported from the small rivers to the BS were higher compared to those of the larger rivers in the world, which indicated that the small rivers in the Bohai Rim could be an important source of the C in the BS. This study would enrich our understanding of environmental evolution in coastal areas with numerous small rivers.

Contribution of the offshore detached Changjiang (Yangtze River) Diluted Water to the formation of hypoxia in summer

The Changjiang (Yangtze River) Diluted Water (CDW) plume substantially impacts the biogeochemical processes off the estuary and its adjacent area, resulting in considerable environmental and ecological effects. Based on survey data in the northeastern area off the Changjiang Estuary (CE) obtained in the summers of 2008 and 2013, the hypoxia induced by the offshore detached CDW plume and the associated controlling mechanisms were investigated. The results show that the offshore transport of the CDW plume caused a dispersed low-salinity area in the northeastern area off the CE during summer, in sharp contrast with the surrounding high-salinity and high-density waters. There was a hypoxic area with low-pH (i.e., acidification) near the 40-m isobath in bottom waters in the northeastern area off the CE, and its position generally corresponded to the surface offshore CDW plume. In the area affected by the offshore low-salinity water, the surface patch-like phytoplankton bloom and the organic debris produced in situ were the material drivers of the bottom oxygen consumption and led to the corresponding relationship between the bottom hypoxic zone and the high chlorophyll-a (Chl-a) area at the surface. We consider that the local stratification caused by the offshore low-salinity water and the stable environment within the detached CDW plume constituted the external dynamic conditions for maintaining the bottom hypoxia. Our results demonstrate that the offshore detached CDW plume in the northeastern area off the CE may contribute to the formation of a local hypoxic center with low pH. This study would provide basis for understanding of the physical-biogeochemical processes and environmental responses in the offshore areas of the CDW plume.

Study of cooling strategy for pressure vessel in pool research reactor at accident situation

Pressure vessel in pool layout is usually used in high power and middle pressure research reactor, Flow inversion and residual heat removal is important problem. The heat removal strategy at accident situation for a pressure vessel in pool layout research reactor was studied in the paper, many cases was researched for the ability of heat removal and safety of core.

Study of cooling strategy for pressure vessel in pool research reactor at accident situation

Pressure vessel in pool layout is usually used in high power and middle pressure research reactor, Flow inversion and residual heat removal is important problem. The heat removal strategy at accident situation for a pressure vessel in pool layout research reactor was studied in the paper, many cases was researched for the ability of heat removal and safety of core.

Holocene carbon accumulation in lakes of the current east Asian monsoonal margin: Implications under a changing climate

Carbon (C) present in lake sediments is an important global sink for CO₂; however, an in-depth understanding of the impact of climate variability and the associated changes in vegetation on sediment C dynamics is still lacking. A total of 13 lakes were studied to quantify the influence of climate and vegetation on the reconstructed Holocene C accumulation rate (CAR) in lake sediments of the modern East Asian monsoonal margin. The corresponding paleoclimate information was assessed, including the temperature (30-90°N in the Northern Hemisphere) and precipitation (indicated by the δ¹⁸O of the Sanbao, Dongge, and Hulu caves). The Holocene vegetation conditions were inferred by pollen records, including arboreal pollen/non-arboreal pollen and pollen percentages. The results showed that the peak CAR occurred during the mid-Holocene, coinciding with the strongest period of the East Asian summer monsoon and expansion of forests. Lakes in the temperate steppe (TS) regions had a mean CAR of 13.41 ± 0.88 g C m^-2 yr^-1, which was significantly greater than the CARs of temperate desert (TD) and highland meadow/steppe (HMS; 6.76 ± 0.29 and 7.39 ± 0.73 g C m^-2 yr^-1, respectively). The major influencing factor for the TS sub-region was vegetation dynamics, especially the proportion of arboreal vegetation, while temperature and vegetation coverage were more important for the HMS. These findings indicate that C accumulation in lake sediments is linked with climate and vegetation changes over long timescales; however, there was notable spatial heterogeneity in the CARs, such as opposing temporal changes and different major influencing factors among the three sub-regions during the mid-Holocene. Aridification and forest loss would decrease C storage. However, prediction of C accumulation remains difficult because of the spatial heterogeneity in CARs and the interaction between the CAR and various factors under future climate change conditions.

Variability in water chemistry of the Three Gorges Reservoir, China

The environmental influence of the Three Gorges Reservoir (TGR) on the Changjiang River has been widely studied since the Three Gorges Dam (TGD) began operation in 2003. However, the changes in water chemistry in the reservoir in response to damming effect variations are poorly documented in the area of this large reservoir. The results suggest that in comparison to the water chemistry before the TGR operation, the inflow concentrations of Mg²⁺, K⁺, Na⁺ and Cl⁻ increased in the TGR, and the abundance of Ca²⁺ and HCO₃^- decreased in the inflow in the period after the TGR filling as a result of climate change and human activities in the Changjiang River basin. The ionic composition in the TGR is primarily controlled by contributions from the upstream region of the Changjiang River but was modified by the interaction between water and rocks within the TGR. The concentrations of most major ions as well as the equivalent ratios of the major ions increased in the TGR after the operation of TGD. This change yielded a 6% increase in the major ion loading downstream of the TGD. The Three Gorges area strongly contributes to the increase in ion loading in the TGR due to enhanced water and rock interactions in comparison with the period before TGD operation.

Sedimentary phosphorus cycling and budget in the seasonally hypoxic coastal area of Changjiang Estuary

Anthropogenic activities have greatly accelerated phosphorus (P) inputs from land to coastal seas. The increased P inputs from major rivers can cause adjacent coastal areas to experience seasonal hypoxia with the enhancing coastal eutrophication, which can subsequently increase P cycling and alter long term preservation. Analysis of sediment core measurements including SEDEX P speciation coupled with diagenetic kinetic models were performed on two cores in the coastal area under the Changjiang river plume, that experiences seasonal hypoxia. It was found that the benthic flux of dissolved reactive phosphate (DRP) in the Changjiang Estuary (CJE) was higher than that of adjacent areas of the Chinese coastal shelf. Sedimentary phosphorus transformations of Fe-bound P and organic P resulted in the in-situ formation of authigenic P (probably apatite), which was the major form of reactive P buried in the sediment. P burial efficiency (PBE) was lower than that of the oxic Chinese shelf but higher than that of other seasonally hypoxic areas in the world away from major river inputs. An exponential relationship between PBE and bottom water dissolved oxygen was developed, which suggested a positive feedback mechanism of increased hypoxia increasing P recycling, and hence intensifying eutrophication. The relatively high input of sediment including detrital P from the adjacent major river can explain many of the observed differences in P cycling from other seasonally hypoxic areas.

Response of the sediment geochemistry of the Changjiang River (Yangtze River) to the impoundment of the Three Gorges Dam

Based on the measurement of major and trace elements in suspended sediments in the low reaches of the Changjiang River during throughout a whole hydrologic year, the origins, seasonal variations, and fluxes of multielements and the human impacts on multielements transport processes have been analyzed along with the influence of weathering in the Changjiang River basin. The results show that most element contents were high in both autumn and winter and low in summer, which was largely caused by the dilution of discharge. Weathering detritus in the Changjiang River basin is the main source of most elements in suspended sediments. However, riverine pollution could bring more loadings of Cd, Pb, As and Zn into river water than it did a few decades ago. The annual average fluxes of Cd, Pb and Zn, which are major contamination elements, to the sea were 179 ± 21 tons/year, 7810 ± 675 tons/year, and 12,000 ± 1320 tons/year, respectively, in which approximately 8.7%, 11.9% and 2.7% of their loadings, respectively, were contributed by pollution inputs. Element exports mainly occurred in the summer (44.4%-57.4%) in the lower part of the Changjiang River. A general relationship between sediment retention and element content suggests a positive feedback mechanism for the decreased number of particles, in which element riverine loadings are reduced due to the enhanced trapping effect by the Three Gorges Dam (TGD). Compared to those in 1980, current element shares of the Changjiang River compared to the global budget have declined due to the construction of the TGD.

Association of PON1 gene polymorphisms with polycystic ovarian syndrome risk: a meta-analysis of case-control studies

PURPOSE

Evidences showed that paraoxonase 1 (PON1) gene polymorphism has an impact on women's susceptibility to polycystic ovarian syndrome (PCOS) by influencing the expression and activity of PON1. However, the effects of three PON1 polymorphisms (- 108 C>T, L55M and Q192R) on the incidence of PCOS have generated inconsistent results. Here, we conducted a meta-analysis to investigate the association between PON1 polymorphisms and PCOS risk.

METHODS

All eligible trials were identified via systematic searches of multiple literature databases. Outcome data were synthesized by using crude odds ratio with 95% confidence interval. Heterogeneity was assessed with the I² test. Publication bias and subgroup analyses were also performed.

RESULTS

A total of 2449 cases and 1977 controls from nine studies were selected for analysis. The pooled results showed a significant association between PCOS risk and PON1 - 108 C/T polymorphism in the following genetic models [allelic, 0.72 (0.56-0.92); homozygote, 0.51 (0.32-0.82); heterozygote, 0.44 (0.25-0.78); and dominant 0.47 (0.29-0.77)]. For the PON1 192 Q/R polymorphism, a significant relationship was found in the allelic model [0.62 (0.41-0.93)] and recessive model [0.61 (0.37-0.98)]. PCOS risk was also linked to PON1 L55M polymorphism in the heterozygote model [0.62 (0.39-0.98)] and dominant model [0.63 (0.41-0.96)].

CONCLUSIONS

Our study has shown that PON1 - 108 C/T polymorphism might be associated with increased risk of PCOS under the allelic, homozygote, heterozygote, and dominant models. Additionally, PON1 192 Q/R and L55M polymorphisms were significantly related only in the allelic and recessive model, and in the heterozygote and dominant model, respectively.

Exploring spatiotemporal changes of the Yangtze River (Changjiang) nitrogen and phosphorus sources, retention and export to the East China Sea and Yellow Sea

Nitrogen (N) and phosphorus (P) flows from land to sea in the Yangtze River basin were simulated for the period 1900-2010, by combining models for hydrology, nutrient input to surface water, and an in-stream retention. This study reveals that the basin-wide nutrient budget, delivery to surface water, and in-stream retention increased during this period. Since 2004, the Three Gorges Reservoir has contributed 5% and 7% of N and P basin-wide retention, respectively. With the dramatic rise in nutrient delivery, even this additional retention was insufficient to prevent an increase of riverine export from 337 Gg N yr^-1 and 58 Gg P yr^-1 (N:P molar ratio = 13) to 5896 Gg N yr^-1 and 381 Gg P yr^-1 (N:P molar ratio = 35) to the East China Sea and Yellow Sea (ECSYS). The midstream and upstream subbasins dominate the N and P exports to the ECSYS, respectively, due to various human activities along the river. Our spatially explicit nutrient source allocation can aid in the strategic targeting of nutrient reduction policies. We posit that these should focus on improving the agricultural fertilizer and manure use efficiency in the upstream and midstream and better urban wastewater management in the downstream subbasin.

[Clinic pathological and ultrasonographic features of primary thyroid lymphoma]

Objective: To analyze the ultrasonographic and clinicopathological features of primary thyroid lymphoma(PTL). Methods: The ultrasonographic and clinicopathological featuresof 21 cases of pathologically-confirmed PTLs were analyzed retrospectively. Results: Of all 21 PTLs, 15 cases were diffuse large B-cell lymphoma, 4 were mucosal-associated lymphoid tissue extranodular marginal zone B-cell lymphoma, 1 was small B-cell lymphoma and 1 was classical Hodgkin lymphoma. Eight cases were proved by pathology with concomitant Hashimoto's thyroiditis. Ultrasonography observed bilateral or unilateral asymmetric goiter (21/21, 100.0%), marked hypoechogenicity (21/21, 100.0%) with posterior acoustic enhancement (19/21, 90.5%), heterogeneous echo texture with interspersed linear echogenic strands or intensive reticular echogenic strands or cloud echogenic, heterogeneous echo texture of thyroid gland (21/21, 100.0%), focal nodular hypoechoic(2/21, 9.5%) with regular or irregular shape, increased vascularity (13/21, 61.9%) and cervical lymphadenopathy (12/21, 57.1%). Two cases involved the anterior cervical muscle and 1 infiltrated trachea. Rapidly enlarging cervical mass were found in 13 cases (13/21, 61.9%)with associated compressive symptoms such as dyspnea, dysphagia and hoarseness. There was no any indisposed symptom in 3 cases. Conclusion: PTL has some common ultrasonographic and clinical features, core needle biopsy should be warranted to prove PTL.Surgical resection should be considered when needed to reduce misdiagnosis.

Multicentre randomized controlled trial with sensor-augmented pump vs multiple daily injections in hospitalized patients with type 2 diabetes in China: Time to reach target glucose

AIM

Sensor-augmented pump (SAP) technology, which combines continuous subcutaneous insulin infusion (CSII) and real-time continuous glucose monitoring (RT-CGM), has been available for several years in China. In this study, the time required to reach predefined glycaemic targets with SAP vs multiple daily injection (MDI) therapy was compared in hospitalized patients with type 2 diabetes mellitus (T2DM).

METHODS

Adults (aged 18-65 years) with T2DM treated with insulin and admitted to hospital for glucose management were randomized to either SAP (Medtronic MiniMed™ Paradigm™ 722 system) or MDI with blinded CGM (Medtronic MiniMed CGMS System Gold™) for a 2-week period. Glycaemic targets were defined as three preprandial measurements between 80 and 130mg/dL (4.4 and 7.2mmol/L) and three 2-h postprandial measurements between 80 and 180mg/dL (4.4 and 10.0mmol/L) within the same day.

RESULTS

When data from 81 patients (40 SAP, 41 MDI) were analysed, 21 patients using SAP therapy, compared with six using MDI therapy, achieved their glycaemic targets within 3 days, and their time to reach their glucose targets was significantly shorter (3.7±1.1 vs 6.3±3.1 days for MDI; P<0.001), while three MDI patients failed to reach glycaemic targets within 14 days. SAP vs MDI patients experienced significantly less hypoglycaemia [sensor glucose<50mg/dL (2.8mmol/L): 0.04% vs 0.32%, respectively; P<0.05] and significantly less hyperglycaemia [sensor glucose>180mg/dL (10mmol/L): 21.56% vs 35.03%, respectively; P<0.05].

CONCLUSION

SAP vs MDI therapy in hospitalized patients with T2DM significantly reduced the time required to achieve glycaemic targets, and such systems may be a cost-effective way to improve glucose control and reduce hospital stays in T2DM patients.

Biogenic silica composition and δ13C abundance in the Changjiang (Yangtze) and Huanghe (Yellow) Rivers with implications for the silicon cycle

The study was carried out to address a method for separation of terrestrial and marine biogenic silica (BSi) in estuaries based on BSi compositions and δ¹³C values in BSi associated organic matter (δ¹³C_BSi). We used two world-class major rivers - the Changjiang (Yangtze) and Huanghe (Yellow) Rivers as examples to illustrate our approach. Our results for these rivers indicate that riverine BSi is comprised mainly of phytoliths and diatoms. River BSi concentrations vary with terrestrial inputs and in-stream primary production. Although the fluvial BSi sources are complex, the terrestrial δ¹³C_BSi signals are quite unique (-24.7±0.8), significantly lower than the marine δ¹³C_BSi values (-21.3±0.07, central Yellow Sea) (p<0.01). Thus, the variation of δ¹³C within BSi organic matter can provide terrestrial source information on the biogeochemistry of silicon in estuaries and the adjacent shelf. The δ¹³C_BSi combination could potentially act as an efficient tool to study environmental change in coastal areas on decadal time-scales since this index may respond to variable terrestrial fluxes from land, as well as to changed phytoplankton assemblages in the coastal ocean.

Composition and variability in the export of biogenic silica in the Changjiang River and the effect of Three Gorges Reservoir

Silicon (Si) plays an essential role in biogeochemical processes, but is still poorly characterized in the river system. This study addressed the biogenic silica (BSi) composition, origin and variation in the Changjiang River, and estimated the impacts of natural processes and human activities on the river Si cycling. Our results indicate that phytoliths comprised 14%-64% of BSi, while diatoms accounted for 34%-85% of BSi. The Changjiang River transported 620Ggyr(-1) of BSi and 2100Ggyr(-1) of dissolved silicate (DSi) loadings, respectively; 55% of the BSi and 51% of the DSi fluxes are transported during the high discharge period from June to September. The Changjiang River carried phytolith BSi mostly comes from the middle and lower reaches area. The ratio of BSi/(BSi+DSi) has decreased from 0.47 before 1980 to 0.19 in 2013-2014 due to the direct retention of BSi. The BSi sedimentation in the Three Gorges Reservoir would cause a decrease of total reactive silica, but contribute to approximately 4%-16% of the DSi loading at the Jiangyin station due to its dissolution. This study demonstrates that phytoliths represent a significant contribution to the biogeochemical cycle of silica in coastal waters, and in-stream process exerts a great influence on the river Si loading and cycling.

Phosphorus speciation, transformation, and preservation in the coastal area of Rushan Bay

Phosphorus (P) speciation, burial, and transformation are poorly constrained under low-oxygen conditions. Sequential chemical extraction techniques, in-situ incubation, and laboratory incubation were employed to explore P cycling in the low-oxygen area of coastal Rushan. The study determined that the total P concentrations in the coastal area of Rushan Bay were higher than those of other China shelf seas, and largely affected by anthropogenic activities. The phosphate (DRP) fluxes in the study area calculated using an incubation method (0-1960μmolm(-2)day(-)(1)) and measured based on pore water gradients (1.5-50.4μmolm(-2)day(-)(1)) were both highly correlated with oxygen conditions. Sediment incubations showed that DRP diffusion from the sediment mainly originates from Fe-P and Auth-P dissolution and that Org-P recycling contributed only a small portion of the total released P pool. The benthic phosphate flux can be 60 times higher under low bottom-water oxygen levels of 63-150μmolL(-1) than under oxygen levels exceeding 150μmolL(-1) in the study area. The P accumulation rates and burial efficiencies in this study area ranged from 16.5-33.3μmolcm(-2)year(-1) and 81.1-83.4%, respectively, and were regulated by the oxygen level and diffusive DRP flux. This study indicates that low oxygen levels between 63 and 150μmol significantly govern P transformation and preservation in the sediment and P pools in the water column.

Generation and Characterization of Patient-Specific iPSC Model for Cardiovascular Disease

Advances in differentiation of cardiomyocytes from human induced pluripotent stem cell (hiPSC) were emerged as a tool for modeling of cardiovascular disease that recapitulates the phenotype for the purpose of drug screening, biomarker discovery, and testing of single-nucleotide polymorphism (SNP) as a modifier for disease stratification. Here, we describe the (1) retroviral reprogramming strategies in the generation of human iPSC, (2) methodology in characterization of iPSC in order to identify the stem cell clones with the best quality, and (3) protocol of cardiac differentiation by modulation of Wnt signaling and β-catenin pathway.

Systemic lupus erythematosus patients in the low-latitude plateau of China: altitudinal influences

The current study was to investigate the features of hospitalized patients with systemic lupus erythematosus (SLE) at different altitudes. The correlation between SLE activity and altitudinal variations was also explored. Medical records of 1029 patients were retrospectively reviewed. Activity of SLE in each organ system was recorded using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). There was no significant correlation between SLE activity and altitudes (r = 0.003, p = 0.159). Age at onset for SLE patients at high altitudes was significantly younger than that at low and moderate altitudes (p = 0.022 and p = 0.004, respectively). Age at SLE admission at low altitudes was significant older than those at moderate and high altitudes (p = 0.011 and p < 0.001, respectively). Patients at high altitudes had shorter duration from disease onset to admission than those at moderate altitudes (p = 0.009). Incidence of Sm antibodies-positive for resident patients at high altitudes was 36.4%, which were higher than that at moderate altitudes (p = 0.003). We found increasing trends of CNS activity in active patients; immunological and renal activities in inactive patients were correlated with elevated altitudes (p = 0.024, p = 0.004, p = 0.005), while arthritis scores in active patients showed the tendency of decreasing with the rise of elevation (p = 0.002). Hemoglobin level, red blood cell and platelet counts at high altitudes were significantly lower than those at low altitudes (p < 0.05, respectively). There was no significant difference in hemoglobin level between moderate- and low-altitude groups (p > 0.05). No significant difference in platelet counts between moderate- and high-altitude groups was observed (p > 0.05). Our findings suggest that some clinical features, laboratory tests and activity of main organs in SLE are influenced by altitudes. Furthermore, organ activities of active and inactive SLE patients have different patterns of altitudinal variations. These distinctive variations likely reveal that peculiar environmental factors at high altitudes can affect the development of SLE.

Molecular imaging of pancreatic islet transplantation

Islet replacement therapy, pancreatic islet transplantation, is considered as a potential option for curing T1DM. However, the significant loss of implanted islets after islet transplantation prevents it from becoming a mainstream treatment modality. Due to the lack of reliable noninvasive real-time imaging techniques to track the survival of the islets, it is impossible to discover the specific causes for the loss of implanted islets, not to mention taking interventions in the early stage. Current achievements in molecular imaging has provided with several promising techniques, including optical imaging, PET and MRI, for noninvasive visualization, quantification and functional evaluation of transplanted islets in experimental conditions. Optical imaging seems to be the most convenient and cost-efficient modality, but the limited penetration distance hinders its application in large animal and human studies. PET combined with target-specific tracers is characterized by high specificity and sensitivity for detection of islet grafts, but observation time is rather short (i.e., several hours). MRI stands out for its long-term visualization of transplanted islet grafts with the aid of contrast agents. However, quantification of islets remains a problem to be solved. A novel technique, microencapsulation, provides a new perspective in multimodal imaging by optimizing the strengths of several modalities together. Although the application of molecular imaging in clinical settings is still limited, significant success and valuable information is achieved in the basic and clinical trials. However, islet transplantation still remains an experimental procedure, with ongoing researches focusing on islets availability, appropriate sites for implantation, new methods using biomaterials (e.g. microencapsulation), immune modulation and more.

The association of plasma free amino acids with liver enzymes in Type 2 diabetic patients

BACKGROUND

Elevated γ-glutamyl transpeptidase (GGT) and alanine aminotransferase (ALT) could predict the risk of Type 2 diabetes (T2D), but the reason for their elevation was unclear. GGT and ALT mediated the metabolism of many amino acids (AA). Up to now, it was not investigated whether abnormal AA concentration was associated with elevated liver enzymes.

AIM

This study was to investigate the status of AA in T2D and their relationship with liver enzymes.

SUBJECTS AND METHODS

A total of 132 T2D patients and 137 healthy controls were recruited. Plasma free AA were measured by high-performance liquid chromatography. The contribution of individual AA to liver enzymes was assessed by stepwise linear regression.

RESULTS

a) The levels of alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, methionine, glutamate, and lysine were higher while the level of glycine was lower in T2D than in controls (all p<0.01). b) Glutamate contributed to GGT in T2D, and its contribution was even greater than that of waist circumference. Leucine, lysine, and glutamate contributed to ALT.

CONCLUSION

There were significant differences in plasma AA profile between T2D and controls. Abnormal AA might contribute to elevated liver enzymes. The interaction between AA, liver enzymes, and the risk of T2D should be further investigated by prospective studies.

A clinical analysis of diabetic patients with hand ulcer in a diabetic foot centre

AIMS

The aim of the study was to explore the prevalence and clinical characteristics of hand ulcer in hospitalized patients with diabetes.

METHODS

We analysed 17 subjects with hand ulcer among diabetic inpatients, who were admitted to the Diabetic Foot Care Center, Department of Endocrinology and Metabolism at the West China Hospital of Sichuan University from April 2003 to December 2008.

RESULTS

The prevalence of diabetic hand ulcer among hospitalized patients (0.37%) was significantly lower than that of diabetic foot ulcers (9.7%, P = 0.000). The mean age was 62.1 +/- 9.4 years. The average known durations of diabetes and glycated haemoglobin (HbA(1c)) were 5.3 +/- 4.9 years and 10.9 +/- 2.4%, respectively. All patients lived in the subtropical zone. Fifteen patients (88.2%) were diagnosed with diabetic peripheral neuropathy. Ten patients had hand infection. After therapy, the ulcers healed in 13 patients (76.5%) and none of them experienced amputation. The average hospital stay for patients with local infection was characteristically longer than that for patients without infection (P = 0.012). The prognosis of the hand ulcer was poorer in the patients who had diabetes for > 3 years compared with those who had diabetes for < 3 years (P = 0.009).

CONCLUSIONS

Diabetic hand ulcer is a relatively rare complication of diabetes in South-West China. Long duration of diabetes, poorly controlled blood glucose, minor trauma and delayed treatment are the risk factors. Diabetic peripheral neuropathy may play an important role in the pathogenesis of hand ulcer. Early control of blood glucose with insulin and early anti-microbial therapy with appropriate antibiotics are crucial. Debridement and drainage are necessary for hand abscesses.

Sterol regulatory element-binding protein-1c knockdown protected INS-1E cells from lipotoxicity

OBJECTIVE

The reduction in insulin secretory capacity and beta-cell mass has been attributed, at least partially, to lipotoxicity, which may contribute to the development of type 2 diabetes. Chronic free fatty acids (FFA) exposure impairs pancreatic beta-cell function and induces beta-cell apoptosis. This study is to elucidate the underlying molecular mechanisms.

RESEARCH DESIGN AND METHODS

We exposed INS-1E pancreatic beta-cell line to palmitate or oleate, and measured the glucose stimulated insulin secretion (GSIS). The effect of FFA on sterol regulatory element-binding protein (SREBP)-1c lipogenic pathway, and expression of genes involved in beta-cell functions, including AMPK (AMP-activated protein kinase), UCP-2 (uncoupling protein-2), IRS-2 (insulin receptor substrate-2), PDX-1 (pancreatic duodenal homeobox-1), GLUT-2 (glucose transporter-2) and B cell lymphoma/leukaemia-2 (Bcl-2) were investigated. Apoptosis of these exposed cells was determined by MitoCapture, Annexin V-Cy3 or terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. Cell lipid accumulation was measured by oil red O staining or TG extraction. Also SREBP-1c expression knockdown were used.

RESULTS

FFA treatment resulted in SREBP-1c overexpression, impaired GSIS, lipid accumulation, apoptosis of INS-1E cells. In addition, the expression of lipogenic genes and UCP-2 were upregulated, but AMPK, IRS-2, PDX-1, GLUT-2 and Bcl-2 were downregulated in the exposed cells. However, these lipotoxic effects of FFA were largely prevented by induction of a SREBP-1c small interfering RNA.

CONCLUSIONS

These data suggest a strong correlation between FFA treatment and SREBP-1c activation in INS-1E cells. SREBP-1c might be a major factor responsible for beta-cell lipotoxicity, and SREBP-1c knockdown could protect INS-1E cells from lipotoxicity, which is implicating a therapeutic potential for treating diabetes related to lipotoxicity.

Muscle infarction involving muscles of abdominal and thoracic walls in diabetes

AIMS

This paper presents two cases of muscle infarction involving four major muscles of the anterior abdominal wall (case 1) and pectoralis major (case 2) in individuals with diabetes.

METHODS

Erythrocyte sedimentation rate (ESR) and creatine kinase (CK) were measured and Doppler ultrasound, an open muscle biopsy (case 1) and magnetic resonance imaging (MRI) (case 2) were performed.

RESULT

The diagnosis of muscle infarction was made by histological findings and MRI images with hyper-intensive signals on a gadolinium-enhanced T2-weighted sequence, respectively. Both patients were treated with bed rest, immobilization of the involved extremities, analgesia and intensive insulin therapy. In addition, anticoagulant drugs such as low molecular weight heparin sodium and cilostazol, and some traditional Chinese medicines such as ligustrazine and salvia miltiorrhiza were administered. The symptoms of both patients resolved gradually after 3 weeks. However, muscle infarction reoccurred in case 1 on the opposite side of the abdomen and recovered after 40 days.

CONCLUSIONS

This is the first report of muscle infarction involving the muscles of anterior abdominal walls and pectoralis major in diabetes. MRI is the best non-invasive technique and T2-weighted imaging is the most valuable method for the diagnosis. In addition to supportive therapy, administration of anticoagulant agents and some Chinese traditional medicine may be useful in symptom relief.