Sediment nitrogen contents controlled by microbial community in a eutrophic tributary in Three Gorges Reservoir, China.

Nitrogen pollution caused serious environmental problems in reservoir ecosystems. Reducing nitrogen pollution by enhancing nitrogen removal in river sediments deserved intensive research. Distributions of nitrogen contents in sediment-water interface were characterized along the Xiangxi bay (XXB), a eutrophic tributary in Three Gorges Reservoir, China. More than 47% of total Kjeldahl nitrogen (TKN) and 67% of total organic nitrogen (TON) were degraded during burial. Higher TN, TON and NH4+ consuming at downstream sites indicated stronger nitrogen mineralization and release due to higher turbulence of the overlying density currents. Nitrifying bacteria, denitrifying bacteria, anaerobic ammonium oxidizing (anammox) bacteria and nitrite/nitrate-dependent anaerobic methane oxidation (N-DAMO) bacteria were detected in nitrate-ammonium transition zone. Nitrogen contents transitions were responded to microbial stakeholders indicated microbially mediated nitrogen cycling in sediments. The dissolved oxygen and nitrate availabilities were the key limits of denitrification and associated reactions. These results suggested microbial mediated nitrogen cycling processes in sediments were critical for nitrogen removal in aquatic ecosystems, and replenishing dissolved oxygen and nitrate was expected to enhance sediment denitrification and strengthen potential environmental self-purification.

Responses of leaf functional traits to different hydrological regimes and leaf economics spectrum in the water level fluctuation zone of Three Gorges Reservoir, China.

A unique riparian ecosystem has been created as a result of anti-seasonal flooding after reservoir operations, which notably influences the distribution patterns of plant communities and their functional characteristics in the riparian zone. Plant functional traits which reflect the physiological and ecological processes of plants in particular ecosystems are crucial for indicating the variations in the ecosystem structure and function. To better understand the adaptation strategies of plants to hydrological changes and provide a scientific basis for the selection of species in the re-vegetation of the newly formed ecosystems, 14 leaf functional traits and leaf economics spectrum (LES) of 19 dominant plants under different hydrological conditions were investigated in the water level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR). The results showed that anti-seasonal flooding has significant effects on the leaf functional traits of plants (P < 0.05). The net photosynthetic rate of annual plants was significantly higher than that of perennial plants (P < 0.05), and there was a significant correlation between leaf phenotypic and photosynthetic traits (P < 0.05). Canonical correspondence analysis showed that soil water content and available phosphorus were the main factors affecting the leaf function of dominant species, indicating that hydrologic factors were still important environmental factors affecting leaf functional traits of dominant species in the WLFZ. And annuals from the WLFZ have characteristics of thick leaves, high photosynthetic rate, short lifespan, and high nutrient concentrations, which make them close to the fast investment-return end of LES. On the contrary, perennials are close to the slow investment-return end of LES. The high productivity investment of annuals is better than the high defense investment of perennials for adapting to the special habitats in the WLFZ. These results indicated that different functional plants in the WLFZ of the TGR under different hydrological regimes can adopt different strategies by weighing the associations and trade-offs between their economic traits.

The influence of hydraulic characteristics on algal bloom in three gorges reservoir, China: A combination of cultural experiments and field monitoring.

It is essential to understand the mechanism of algal bloom and develop effect measures to control the hazard in aquatic environment, such as large reservoirs. In this study, a series of experiments, along with field observation from 2007 to 2016, were carried out to identify the hydrodynamic parameters that drive the algal bloom in the Three Gorges Reservoir (TGR), China, and their threshold values were determined. The results show that algae concentration was markedly diluted with a short retention time, and the threshold value of the retention time to avoid algal bloom was approximately less than 3 days. With strong stratification, the algae concentration was able to approach to the level of algal bloom in 10 days, even when the water temperature is lower than 12 °C. The ratio of mixing depth to euphotic depth (Zm/Ze) had significant negative correlations with both algae concentration and algae specific growth rate (SGR). The field monitoring data indicated that Zm/Ze is an important hydrodynamic parameter which sensitively affects algae growth and concentration. This study made the first attempt to determine Zm/Ze >2.8 to restrain algal bloom in the TGR. Our findings shed light on the influence of critical depth on the algal bloom in the TGR, and the results can serve to control algal bloom in reservoirs through discharge operation.

Capsular Polysaccharide From Bacteroides fragilis Protects Against Ulcerative Colitis in an Undegraded Form.

The prominent human symbiont Bacteroides fragilis protects animals from intestinal diseases, such as ulcerative colitis, and its capsular polysaccharide plays a key role in reducing inflammation. B. fragilis strain ZY-312 was isolated from the feces of a healthy breast-fed infant, and the zwitterionic capsular polysaccharide zwitterionic polysaccharide, TP2, was extracted. In rats with 2,4-dinitrobenzenesulfonic acid (DNBS)-induced enteritis, TP2 at an optimal dose of 2.5 mg/kg could significantly alleviate enteritis and reduced the degree of intestinal adhesions, the intestinal ulcer area, and the incidence of ulcers in rats. To understand the underlying mechanism, TP2 was labeled with Fluorescein isothiocyanate and orally administered at a dose of 2.5 mg/kg in rats. TP2 was mainly distributed in the cecum and colorectum, but it was not detected in the blood and other organs except that a compound with a molecular weight greater than that of TP2-FITC was found in liver tissue. During the absorption, distribution, metabolism, and excretion, TP2 was indigestible. These results were further confirmed by investigation in the simulated gastric, intestinal fluid, and colonic fluid with fecal microbiota in vitro, where TP2 remained unaltered at different time points. Furthermore, flora composition was analyzed in simulated colonic fluid with TP2 added and it was found that TP2 increased the abundance of Faecalibacterium, Enterococcus romboutsia, and Ruminococcaceae, whereas the abundance of the phylum Proteobacteria represented by Sutterella, Desulfovibrio, and Enterobacteriaceae was decreased. However, the amount of short-chain fatty acids in the simulated colonic fluid was not changed by intestinal flora post-TP2 addition. In conclusion, these findings confirmed that TP2, a capsular polysaccharide of B. fragilis, protects against ulcerative colitis in an undegraded form.

[Analysis of Total Organic Carbon Source Differences Between New and Old Cascade Reservoirs using Carbon and Nitrogen Isotopes].

The ecological problems due to reservoir construction are causing unprecedented concern. To reveal the differences in organic carbon distribution characteristics and sediment sources of total organic carbon (TOC) between the old and new reservoirs, water samples, and sediment samples from reservoirs constructed in the three different periods of Miaowei, Gongguoqiao, and Dachaoshan were collected in November 2017. The temperature (T), dissolved oxygen (DO), TOC, redox potential (ORP), total nitrogen (TN), and total phosphorus (TP) of the water samples were measured. The isotopes 15N and 13C were used as indicators with IsoSource software to analyze the contributions of TOC sources and their source materials to the corresponding reservoir sediments, in order to explore the carbon cycle mechanism and evolution mode of reservoir. The results showed that the average concentrations of organic carbon in the waters of the Miaowei, Gongguoqiao, and Dachaoshan Reservoirs were 0.95 mg·L-1, 1.97 mg·L-1, and 4.64 mg·L-1, respectively. The range of organic carbon content in the corresponding sediments was 4.41-81.63 g·kg-1, 18.30-28.42 g·kg-1, and 9.16-14.46 g·kg-1, respectively. The cascade construction of the reservoirs resulted in a difference between the sediment sources of the new and old reservoirs and the surrounding recharge area, meaning that the TOC of the new and old reservoirs were significantly different. For the TOC of waterbodies, the difference between the thermodynamic state of water and dissolved oxygen indirectly affects the distribution trend of TOC. The sediments mainly reflect the influence of source elements, that is, the ability of the sedimentary environment to preserve organic matter was the main cause of the vertical distribution of DCS, MV, and GGQ sediments. In the evolution mode of cascade reservoir, the research shows that it can be preliminarily set as three stages. Firstly, due to the short age of MV, it is in the first stage and mainly accumulates the TOC from the upstream. GGQ is longer than the age of MV, and it is mainly used to decompose the upstream TOC, so it is defined as in the second stage. Finally, as an old reservoir, DCS mainly accumulates TOC sources around the reservoir, which can be regarded as the third stage.

[Speciation and Transformation of Phosphorus in Sediments During the Redox Cycle].

To study the mechanism of phosphorus cycling in sediment during the redox cycle, changes in physicochemical properties of overlying water and various forms of phosphorus in sediments were investigated as a way to quantify the redistribution of phosphorus. Additionally, the effect of the release flux of phosphate from sediments under controlled redox conditions was analyzed. The results showed that the redox potential Eh and the pH system, sulfur system, carbon system, and iron-related changes exhibited periodicity and played an important role in explaining the migration and transformation mechanism in the interface phosphorus of the sediment-water phase. During the redox cycle, the phosphorus content of each species varied with the redox conditions and time. Because of this, quantitative analysis based on changes in water-sediment phosphorus could be obtained. Reducible phosphorus (BD-P) and iron-aluminum-bound phosphorus (NaOH-rP) were reversibly redistributed into weakly adsorbed phosphorus (NH4Cl-P), polyphosphorus/organophosphorous (NaOH-nrP), residual phosphorus (Rest-P), and interstitial water-soluble active phosphorus (SRP). Additionally, 93.7% of phosphorus in the sediment was not released into the water phase during the reduction reaction. The 92% of change in the overlying water total phosphorus (TP) was the SRP of overlying water, which showed that the exchange of the sediment-water phase were mainly soluble active phosphorus in this cycle. According to Fick's First Law, the maximum phosphorus flux was 0.58 mg·(m2·d)-1 during reduction and 0.16-0.22 mg·(m2·d)-1 on day seven of the oxidation phase. In the oxidation stage, the diffusion flux decreased with time, while the opposite trend occurred in the reduction reaction. This indicated that the anaerobic state accelerated the diffusion of phosphorus in sediments, and that oxygen exposure decreased the phosphorus flux in sediments.

Clinical analyses of clustered microcalcifications after autologous fat injection for breast augmentation.

BACKGROUND: Autologous fat injection for breast augmentation has been disputed with regard to its complications for many years, especially regarding calcifications, most of which present with benign features. In previous studies, clustered microcalcifications were not observed after fat injection for breast augmentation, which are usually regarded as malignant calcifications. METHODS: From July of 1999 to December of 2009, autologous fat injection for breast augmentation was performed for both breasts in 48 patients. Eight patients with clustered microcalcifications found by mammography after surgery were analyzed retrospectively. For the nonpalpable breast lesions in three patients, the clustered microcalcifications were resected with the help of needle localized breast biopsy. The palpable lump, including clustered microcalcifications, was resected 1 cm away from its border in the other patients. All of the specimens were submitted to pathologic examination. RESULTS: The digitized mammographic films of eight of 48 patients (16.7 percent) showed clustered microcalcifications after autologous fat injection, which were highly suspected of being breast carcinoma microcalcifications, whereas all pathologic examinations indicated fat necroses. CONCLUSIONS: Clustered microcalcifications can be found after autologous fat injection for breast augmentation, which cannot be distinguished from malignancy. The mammographic confusion constitutes the problem rather than the success of the procedure itself, and the method should continue to be prohibited.

[Application of abdominoplasty and polypropylene to repair the abdominal defect].

OBJECTIVE: To introduce a operation method of repairing the abdominal defect with abdominoplasty and polypropylene. METHODS: 27 patients were treated with abdominoplasty and polypropylene. RESULTS: Follow up 3 - 20 months, the focus in inferior abdominal wall were removed thoroughly. The incision is cure with A level. No weakness, bulk, hernia and complication occur in the abdominal wall. CONCLUSIONS: The method of repairing the abdominal defect with abdominoplasty and polypropylene is a good method. It is a simple method. Its' result is relied.

[Analysis of Millard II technique for correcting secondary deformities of unilateral cleft lip].

OBJECTIVE: To analyze the Millard II technique for correcting secondary deformities of unilateral cleft lip. METHODS: The Millard II technique was used to correct secondary deformities of unilateral cleft lip in 42 patients from March of 2003 to September of 2004. Dissection was made between the alar cartilage and skin, and the alar cartilage was suspended. RESULTS: The postoperative follow-ups with 3 approximately 6 months revealed good results of the symmetrical nostrils and philtrums, prolonged columella nasi, good-shaped cupid's bow, and invisible scar. CONCLUSIONS: The Millard II technique could be an ideal method to correct secondary deformities of unilateral cleft lip. Releasing and suspending alar cartilage spontaneously at the same time can correct nasal deformity adequately.

[The application of pedicled anterolateral thigh fasciocutaneous flaps for reconstruction of perineal and inguinal defects].

OBJECTIVE: To evaluate a method for the reconstruction of defects of perineum and groin with pedicled anterolateral thigh fasciocutaneous flaps. METHODS: From July 2003 to February 2005, 12 pedicled anterolateral thigh fasciocutaneous flap based on the perforators of lateral circumflex femoral artery had been designed and transferred to the defects of perineum and groin. RESULTS: Anterolateral thigh fasciocutaneous island flaps were performed in twelve patients. The size of the transferred flap ranged from 8 cm x 11 cm to 18 cm x 20 cm. Only one patient developed superficial cutaneous necrosis in the posterior aspect of the flap because of fecal contamination and infection. The wounds healed secondarily. CONCLUSIONS: Despite variable vascular anatomy and technical difficulties in elevating the anterolateral thigh flap, the anterolateral thigh flap is a good choice for perineum and groin reconstruction.

[TRAM flap in conjunction with latissimus dorsi muscle flap for breast reconstruction].

OBJECTIVE: To investigate a method to reconstruct the breast and repair the chest wall defects at the same time. METHODS: The operation procedure combined the transverse rectus abdominis myocutaneous (TRAM) flap with the latissimus dorsi muscle(LDM) flap for breast reconstruction and repair of chest wall defect. Two patients underwent delayed breast reconstruction using this technique. RESULTS: 8 flaps in the four patients survived completely. The aesthetic results were very good. CONCLUSION: This method can be used to reconstruct breast and repair the defect of chest wall at the same time, avoiding the disadvantage in the flap transfer of TRAM or LDM.