Establish a New Diagnosis of Sarcopenia Based on Extracted Radiomic Features to Predict Prognosis of Patients With Gastric Cancer.

Background: Preoperative sarcopenia is a prognostic risk factor for gastric cancer (GC). This study aimed to determine whether radiomic sarcopenia features on computed tomography (CT) could be used to diagnose sarcopenia preoperatively, and whether they could be used to accurately predict the postoperative survival and complication prognosis of patients with GC. Methods: We retrospectively analyzed data of 550 patients with GC who underwent radical gastrectomy. The patients were divided into training (2014-2016) and validation (2017-2019) cohorts. We established a radiomics-based diagnosis tool for sarcopenia. Thereafter, univariate and multivariate analyses of diagnostic factors were carried out. Receiver operator characteristic (ROC) curves and area under the curve (AUC) were used to compare different diagnostic models. The Kaplan-Meier method was used to estimate the survival curve. Results: Radiomic sarcopenia correlated with complications and long-term survival. Skeletal muscle index, grip strength, and walking speed were correlated with postoperative complications in both cohorts (AUCs: 0.632, 0.577, and 0.614, respectively in the training cohort; 0.570, 0.605, 0.546, respectively, in the validation cohort), and original sarcopenia was more accurate than any of these indicators. However, radiomic sarcopenia has a higher AUC in predicting short-term complications than original sarcopenia in both groups (AUCs: 0.646 vs. 0.635 in the training cohort; 0.641 vs. 0.625 in the validation cohort). In the training cohort, the overall survival time of patients with original sarcopenia was shorter than normal patients (hazard ratio, HR = 1.741; 95% confidence interval [CI], 1.044-2.903; p = 0.031). While radiomic sarcopenia had a greater prognostic significance, the overall survival time of patients with radiomic sarcopenia was significantly worse than normal patients (HR, 1.880; 95% CI, 1.225-2.885, p = 0.003). Conclusion: Extracted sarcopenia features based on CT can predict long-term survival and short-term complications of GC patients after surgery, and its accuracy has been verified by training and validation groups. Compared with original sarcopenia, radiomic sarcopenia can effectively improve the accuracy of survival and complication prediction and also shorten the time and steps of traditional screening, thereby reducing the subjectivity effects of sarcopenia assessment.

[Characteristics and Source Analysis of Water-soluble Inorganic Pollution in PM2.5 During Summer in Central China].

In order to investigate the pollution characteristics and sources of water-soluble ions in atmospheric PM2.5 in different regions of central China during summer, Wuhan, Suizhou, and Pingdingshan were selected as urban, suburban, and rural monitoring stations, respectively, to collect PM2.5 samples, and the mass concentration of PM2.5 in the atmosphere and the contents of eight water-soluble ions were analyzed. The results showed that ρ(water-soluble ions) at the three sites showed obvious spatial distribution characteristics, with Pingdingshan[(36.29±9.82) µg·m-3] > Wuhan[(32.55±10.05) µg·m-3] > Suizhou[(26.10±6.23) µg·m-3], accounting for 52.47%, 51.32%, and 48.61% of the PM2.5 mass concentration, respectively. In the Pingdingshan station, the proportion of water-soluble ions was the largest due to biomass combustion in the rural area. Additionally, SNA (SO42-, NO3-, and NH4+) were the main ionic components, accounting for 95.65%, 96.12%, and 97.33% of the total water-soluble ions, respectively. The mean values of SOR of the Wuhan (0.64) and Suizhou (0.63) stations were higher than that of the Pingdingshan station (0.50), whereas the NOR values of the Wuhan (0.18) and Pingdingshan (0.19) stations were higher than that of the Suizhou station (0.15). The difference in SOR and NOR among stations was affected by the secondary conversion mechanism, the ammonia-rich environment, and the surrounding traffic sources, respectively. The PM2.5 at the Wuhan and Pingdingshan stations was in general alkaline, whereas at the Suizhou station it was neutral or weakly acidic, which was mainly caused by differences in NH4+. NH4+ mainly existed in the form of (NH4)2SO4 and NH4NO3 at the Wuhan and Pingdingshan stations, whereas at the Suizhou station it mainly existed in the form of (NH4)2SO4 or (NH4)HSO4. PCA-MLR analysis revealed that the Wuhan (89.27%) and Suizhou (67.38%) stations were the most affected by secondary conversion sources, whereas the Wuhan station was also affected by industrial sources (8.54%) and coal sources (2.27%). The pollution sources of the Suizhou station also included biomass combustion (24.42%) and dust sources (8.25%). The Pingdingshan station was most affected by biomass combustion (58.37%), followed by dust and combustion sources (38.05%) and traffic sources (3.58%). The analysis of potential sources of SNA (PSCF) showed that the main potential source areas of Wuhan were the boundary of Hubei, Henan, and Anhui and the southwest area of Anhui. Suizhou and Pingdingshan were affected by long-distance transport, and the main potential source regions were distributed in Shanghai, Jiangsu, and Anhui provinces from the east coast to the west.

[Pollution and Potential Ecological Risk Assessment of Heavy Metals in Surface Sediments of Tangxun Lake].

In order to understand the pollution characteristics, spatial distribution, potential sources, and ecological risk of heavy metals in the sediments of Tangxun Lake, the contents of heavy metals (As, Hg, Cd, Cr, Cu, Pb, Zn, and Ni) in the surface sediments of Tangxun Lake were analyzed, and the pollution status and potential ecological risk degree of heavy metals in the sediments were evaluated using the geo-accumulation index and potential ecological risk index. The potential sources of heavy metal pollutants were analyzed by correlation and principal component analysis. The results showed that except for Cr, the contents of other heavy metals were higher than their background values. The contents of Hg, Cd, Zn, and Cu were higher in the southwest and northeast corners of the lake, which may come from the combined pollution of sewage discharge, fisheries, and surrounding industrial and agricultural activities. The geo-accumulation index and potential ecological risk showed that Hg and Cd were in moderate pollution; Cu, Pb, and Zn were in non-light pollution; and As, Cr, and Ni were in non-pollution. Except for Hg and Cd, there were serious and serious potential ecological risks, and the other elements were at a low risk level. The heavy metals in the surface sediments of Tangxun Lake showed a high ecological risk level.

Effect of Short-Term Preoperative Parenteral Nutrition Support for Gastric Cancer Patients with Sarcopenia: a Propensity Score Matching Analysis.

INTRODUCTION: Sarcopenia is well recognized as an unfavorable prognostic marker for gastric cancer (GC) patients. Currently, few nutritional interventions-such as parenteral nutrition-exist for the treatment of patients with sarcopenia. This study aimed to estimate the effectiveness of short-term preoperative parenteral nutrition (PN) in GC patients with sarcopenia. MATERIALS AND METHODS: We collected data on GC patients with sarcopenia who underwent radical gastrectomy at our hospital from 2010 to 2018. A 1:1 ratio propensity score matching (PSM) was applied to establish the PN and control groups. Data were analyzed using the chi-squared, Mann-Whitney U, and Fisher's exact tests. RESULTS: In total, 428 patients met the inclusion criteria, and the propensity scores identified 166 matched pairs of patients with sarcopenia. The overall incidence of postoperative complications between both groups was not significantly different (P = 0.728). The PN group had a lower rate of intra-abdominal infection (P = 0.032) and higher hospitalization costs (P < 0.001) than the control group. Multivariate analysis demonstrated that age, Charlson score, and TNM stage were independent risk factors for postoperative complications. Additionally, subgroup analysis revealed that short-term preoperative PN support is associated with decreased postoperative surgical complications in patients with albumin levels < 35 g/L (P = 0.025). CONCLUSION: Short-term preoperative PN support is not associated with reduction of overall complication rate in patients with GC and sarcopenia. However, those with sarcopenia and hypoalbuminemia benefited from preoperative PN support.

[Characteristics of grassland degradation and its relationship with climate factors on Qinghai-Tibetan Plateau, China]. / é’è—é«˜åŽŸè‰åœ°é€€åŒ–ç‰¹å¾åŠå ¶ä¸Žæ°”å€™å› å­çš„å ³ç³».

Understanding the distribution, characteristics, and changing trend and persistence of grassland degradation and revealing its mechanism on the Qinghai-Tibetan Plateau can provide scientific basis for effective grassland management and conservation. We selected grassland coverage as the remote sensing monitoring index to establish the remote sensing monitoring and evaluation index system of grassland degradation and evaluate grassland degradation during 2016 to 2020 on the Qinghai-Tibet Plateau. The changing trend and persistence of grassland coverage were analyzed using linear regression and Hurst index analysis on a long time series scale (1982-2020). The partial correlation analysis was used to examine the influence of climate on grassland degradation. The results showed that grassland degradation reached 24.3% during 2016 to 2020, which was mainly light and moderate degradation, and largely distributed in low altitude and high fractional vegetation cover areas. From 1982 to 2020, grassland coverage tended to increase in the north, west and southwest, and decreased in the east and center of the Qinghai-Tibetan Plateau. The Hurst index of grassland coverage was less than 0.5 in 98.1% of the total grassland, indicating grassland coverage showed negatively persistent. The partial correlation coefficient between grassland coverage and precipitation (0.096) was higher than that of temperature (-0.033). About 16.0% area was dominated by temperature, which was mainly distributed in the central and southeast. About 12.2% area was dominated by precipitation, which was distributed in the northeast and west of the Qinghai-Tibetan Plateau.

Impact of malnutrition diagnosed using Global Leadership Initiative on Malnutrition criteria on clinical outcomes of patients with gastric cancer.

OBJECTIVE: Our objective is to validate the effectiveness of the Global Leadership Initiative on Malnutrition (GLIM) criteria in malnutrition diagnosis compared with Patient-Generated Subjective Global Assessment (PG-SGA) and assess the impact of malnutrition diagnosed using GLIM criteria on the clinical outcomes of patients with GC. METHODS: We retrospectively analyzed the data of 895 patients who underwent radical gastrectomy at the First Affiliated Hospital of Wenzhou Medical University. Nutrition assessment was performed on all patients according to the GLIM criteria and PG-SGA. The κ statistic was used to evaluate the agreement between two methods. Multivariate logistic regression and Cox regression based on single-factor analysis were used to predict postoperative complications and overall survival rates. RESULTS: Based on the GLIM criteria, 38.3% of the patients were diagnosed as malnourished, including 21.7% Stage I (moderate malnutrition) and 16.6% Stage II (severe malnutrition). GLIM criteria had a moderate agreement with PG-SGA (κ = 0.548). Patients in the Stage II malnutrition group had a higher incidence of complications, a longer postoperative length of stay, and higher hospitalization costs. Logistic regression showed that Stage II malnutrition was an independent risk predictor of postoperative complications (odds ratio, 3.28; 95% confidence interval [CI], 2.18-4.94). Furthermore, Cox regression analysis showed that both Stage I (hazard ratio [HR], 1.52; 95% CI, 1.11-2.07; P = .009) and Stage II (HR, 1.85; 95% CI, 1.34-2.53; P < .001) malnutrition were independent risk predictors of overall survival. CONCLUSION: Diagnosis of malnutrition according to the GLIM criteria is useful in predicting the adverse postoperative clinical outcomes of patients with gastric cancer.

[Characteristics and Origin Analysis of Air Pollution During the Spring Festival in Linfen, Fenwei Plain].

In recent years, frequent haze episodes have resulted in the deterioration of air quality of the Fenwei Plain during winter and holidays. Besides coal combustion and industrial emissions, the topography and climate of the Fenwei Plain were also the main causes of the haze. The samples were collected in Linfen of Fenwei Plain during the Spring Festival from February 2 to February 13, 2019. The 13 elements(Li, Be, Ti, Rb, Sc, Y, La, Ce, Zr, V, Tl, U, and Sn) in PM2.5 were determined by inductively coupled plasma mass spectrometry(ICP-MS). Combined with the meteorological data, the spatial and temporal distribution of pollutants and potential source analysis were evaluated by cluster analysis and backward trajectory. The average concentration of SO2 was 58.39 µg·m-3 during the sampling period, which exceeded the 24 h average mass concentration limit(50.00 µg·m-3) of national ambient air quality standard(GB 3095-2012). The average concentrations of O3, NO2, and CO was 52.15 µg·m-3, 29.02 µg·m-3, and 2.29 mg·m-3, respectively. The results showed that SO2 was the dominated pollutant. NO2 and CO were mainly affected by diffusion from urban areas. The backward trajectory analysis indicated that the basin topography of the Fenwei Plain may be the main cause of the haze. The analysis of potential source contribution function(PSCF) of soil sources showed that the potential dominated areas included Northern Shaanxi, southern Gansu and Southern Ningxia., which were mainly affected by the monsoon climate.

[Characteristics and Health Risk Assessment of Heavy Metals in PM2.5 Under Winter Haze Conditions in Central China: A Case Study of Huanggang, Hubei Province].

To explore the pollution characteristics and potential health risks of heavy metals in PM2.5 on haze days in Central China, PM2.5 samples were collected from the Huanggang monitoring station, a regional observation point in Central China, between January 13 and 24, 2018. The contents of Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Sn, and Pb in PM2.5 were analyzed by inductively coupled plasma mass spectrometry(ICP-MS), and the enrichment factor method was used to determine the potential risk based on the exposure model recommended by the Environmental Protection Administration(EPA). The results showed that during the observation period, the concentrations of Zn in PM2.5 were highest, and the concentrations of the carcinogens As and Cd were higher than the secondary standard limits of China's ambient air quality standard(GB 3095-2012), with 70% of these elemental concentrations accounting for the largest proportion in the middle haze period. The enrichment factor analysis showed that Cd, Sn, Co, Pb, and Zn were the most abundant elements, especially during the middle haze period, and were mostly derived from transportation and coal combustion. The results of the human health risk assessment showed that exposure via hand-mouth feeding was the main non-carcinogenic risk, and the exposure and non-carcinogenic risks of children were significantly higher than those of adults. Pb poses a non-carcinogenic risk to children, while heavy metals in PM2.5 pose no non-carcinogenic risks to adults and carcinogenic heavy metals pose no carcinogenic risks.

Impact of Preoperative Short-Term Parenteral Nutrition Support on the Clinical Outcome of Gastric Cancer Patients: A Propensity Score Matching Analysis.

OBJECTIVES: Nutrition status is of great significance to the clinical outcome after major abdominal surgery. However, the effect of preoperative short-term parenteral nutrition (PN) support among gastric cancer (GC) patients remains unknown and was evaluated in the current study. METHODS: We retrospectively analyzed 455 nutritionally at-risk GC patients after radical resection from 2010 to 2016. We matched patients with 3-7 days of PN support to those without PN support. χ2 And Mann-Whitney U tests were used to compare differences between the PN and control groups. RESULTS: The propensity-matched sample included 368 GC patients (PN group, n = 184; control group, n = 184). The PN and control groups did not differ regarding postoperative complications (P = .528). The incidence of anastomotic leakage in the PN group was lower than in the control group (P = .011), whereas other complications were not found to differ between the groups. The hospitalization cost of the PN group was significantly higher than that of the control group (P < .001), whereas other outcome indicators were similar. Subgroup analysis showed that short-term PN support may have an improved benefit for patients with serum albumin level <35 g/L, but not at the level of statistical significance (P = .17). CONCLUSION: Short-term PN support did not significantly improve the short-term clinical outcomes of nutritionally at-risk GC patients, with the exception of a lower incidence of anastomotic leakage. Considering that short-term PN support increases economic burden, PN should not be the preferred method among these patients.

[Characteristics and Sources of 12 Trace Amount Elements in PM2.5 During a Period of Heavy Pollution in Huanggang, Central China].

This study provides data and theoretical support for the prevention and control of air pollution in central China. From January 13, 2018, to January 25, 2018, 48 PM2.5 samples were collected in Huanggang by particulate matter samplers during a severe pollution episode. Twelve elements (Li, Be, V, Se, Sr, Mo, Ag, Ba, Tl, Th, Bi, and U) were analyzed by ICP-MS. A positive definite matrix factor (PMF), trajectory model of the cluster analysis, potential source analysis (PSCF), and the concentration weight analysis method (CWT) were applied to analyze the potential pollution sources and determine the transmission channel. The results showed that the internal cause of the pollution was the appearance of static, stable, and high humidity meteorological conditions, while the external cause was the input of pollution. Five types of pollution source were determined:fuel combustion (10.59%), crustal (24.22%), industry (3.16%), coal (47.57%), and traffic (14.45%). Two main types of air flow path were found; short distance transmission accounted for 62.50% whereas long distance transport accounted for 37.50%. The major contributors to the pollution included central and eastern Hubei, northeastern Hunan, southwestern Anhui, and southern Henan. North-south transmission channels were observed for central China. In addition to local pollution, the impact of regional transmission should not be ignored. In the emergency response period for heavy pollution during the autumn and winter, all regions need to control emission reduction measures. Joint prevention and control are the keys to air pollution control.

Metabolic syndrome-related sarcopenia is associated with worse prognosis in patients with gastric cancer: A prospective study.

OBJECTIVES: Sarcopenia and metabolic syndrome (MetS) are associated with the prognosis from malignant tumors. However, evidence of the relationship between sarcopenia and MetS among gastric cancer (GC) patients following radical gastrectomy is lacking. This study assessed the association between preoperative sarcopenia and MetS among GC patients and analyzed the prognosis of patients with different malnutrition statuses. METHODS: We prospectively assessed the preoperative statuses of sarcopenia and MetS among patients who underwent radical gastrectomy from July 2014 to December 2017. We combined sarcopenia and MetS to generate four groups: MetS-related sarcopenia group (MSS), sarcopenia group (S), MetS group (MS), and normal group (N). RESULTS: A total of 749 patients with resectable GC were included in this study. Preoperative MetS was associated with sarcopenia (p < 0.001). Multivariate logistic regression presented that MetS-related sarcopenia (OR = 2.445; p = 0.010) and sarcopenia alone (OR = 2.117; p = 0.001) were independent predictors of grade Ⅱ and above complications, while MetS alone was not (p = 0.342). Cox regression analysis revealed that MetS-related sarcopenia led to the worst prognosis in the four groups (MSS vs MS: HR = 3.555, p < 0.001; MSS vs N: HR = 2.020, p = 0.003; MSS vs S: HR = 1.763, p = 0.021). However, the MetS group had better prognosis than the normal group (MS vs N: HR = 0.568, p = 0.048). CONCLUSION: Preoperative MetS was associated with sarcopenia among GC patients. MetS-related sarcopenia resulted in a significantly worse prognosis. The long-term prognoses of patients with sarcopenia were impaired by preoperative MetS, while patients without sarcopenia benefited. Thus, patients with both sarcopenia and MetS require more medical interventions.

Diffuse Reduction of Spleen Density Is an Independent Predictor of Post-Operative Outcomes After Curative Gastrectomy in Gastric Cancer: A Multi-Center Study.

Objectives: The present study aimed to explore the association between spleen density and post-operative outcomes of patients after curative gastrectomy. Methods: From June 2014 to December 2015, we conducted a retrospective study to analyze pertinent clinical data from gastric cancer patients who underwent gastrectomy at the First and the Second Affiliated Hospital of Wenzhou Medical University. Spleen density was determined via computed tomography scans. Univariate and multivariate analyses were performed to determine the risk factors associated with post-operative outcomes after gastric cancer surgery. Results: Three hundred and ninety five patients were included, of whom 98 (24.8%) were defined as having a diffuse reduction of spleen density based on diagnostic cutoff values (spleen density ≤43.89 HU). Multivariate analysis revealed diffuse reduction of spleen density as an independent risk factor for post-operative complications and long-term overall survival. Conclusions: Spleen density can predict severe postoperative complications and long-term overall survival in gastric cancer patients. As an imaging evaluation method, spleen density is a novel tool can be used in clinical as a prognostic predictor for patients with gastric cancer.

Use of a compact high-definition two-dimensional exoscope in surgical treatment of large vestibular schwannoma.

BACKGROUND: Extra-corporeal video telescope operating monitor system provides a necessary instrument to perform high-precision neurosurgical procedures that could substitute or supplement the traditional surgical microscope. The present study was designed to evaluate a compact high-definition two-dimensional exoscope system for assisting in surgical removal of large vestibular schwannoma (VS), as an alternative to a binocular surgical microscope. METHODS: Patients with Koos grade 3 and grade 4 VS undergoing surgery were enrolled in this prospective cohort study between January 2013 and June 2018. The demographics and tumor characteristics (size, Koos grade, composition [cystic or solid mass]) were matched between the two groups of patients. The following outcome measurements were compared between the two groups: duration of surgery, volume of blood loss, extent of tumor resection, number of operating field adjustments, pre- and post-operative facial and cochlear nerve function evaluated at 3 months post-surgery, complications and surgeons' comfortability. RESULTS: A total of 81 patients received tumor resection through the retrosigmoid approach under either an exoscope (cases, n = 39) or a surgical microscope (control, n = 42). Patients in the two groups had comparable tumor location (P = 0.439), Koos grading (P = 0.867), and composition (P = 0.891). While no significant differences in the duration of surgery (P = 0.172), extent of tumor resection (P = 0.858), facial function (P = 0.838), and hearing ability (P = 1.000), patients operated on under an exoscope had less blood loss (P = 0.036) and a fewer field adjustments (P < 0.001). Both primary and assistant surgeons reported a high level of comfort operating under the exoscope (P = 0.001 and P < 0.001, respectively). CONCLUSIONS: The compact high-definition two-dimensional exoscope system provides a safe and efficient means to assist in removing large VSs, as compared to a surgical microscope. After the acquaintance with a visual perception through a dynamic hint and stereoscopically viewing corresponding to the motion parallax, the exoscope system provided a comfortable, high-resolution visualization without compromising operational efficiency and patient safety.

[Characteristics and Sources of Elements in PM2.5 During Summer for Three Typical Cities in Pingdingshan-Suizhou-Wuhan, Central China].

This study investigates the elemental characteristics and sources of aerosol fine particulate matter (PM2.5) samples obtained from Pingdingshan, Suizhou, and Wuhan, Central China, in June 2017. Thirteen kinds of elements (Ti, Zn, Cu, Cr, As, Pb, Fe, Ni, Se, V, Sb, Cd, and Co) were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and three source identification methods-enrichment factor, principle component analysis and multiple linear regression (PCA-MLR), and backward trajectory clustering-were applied. The results showed that Zn was the highest trace element in PM2.5 in samples from Pingdingshan, Suizhou, and Wuhan, and that the concentration of As exceeded the annual limit of Chinese air quality standards (GB 3096-2012). Concentrations of Pb and Cd in PM2.5 in samples from the three cities during the summer were low. The enrichment factor coefficients for Se, Sb, Cd, As, Cu, and Zn exceeded 10, which suggests that summer pollution from human activities was serious, for example, the enrichment factor coefficient for Se was>600. PCA-MLR and backward trajectory clustering analysis results showed that the main pollution sources in Pingdingshan during the summer were industrial fuel oil (57.90% of total), traffic pollution (24.40%), coal combustion (6.10%), and mine soil (11.60%). The main pollution source in Suizhou was fuel, which contributed 54.30% of the total. Wuhan was mainly affected by industrial emissions (60.80% of the total) and motor vehicle pollution (39.20%). Hence, Wuhan and Suizhou were mainly affected by local source emissions, whereas Pingdingshan was jointly affected by local emissions and regional inputs during the summer.

[Microbial Community Structure and the Distribution of Antibiotic Resistance Genes in Soil Contaminated by Sulfamethoxazole].

A pot experiment was carried out to simulate soil contaminated by sulfamethoxazole at different concentrations. The community structure of soil microorganisms was investigated using Illumina high-throughput sequencing, and 64 subtypes of antibiotic resistance genes (ARGs) resistant to six classes of antibiotic were also analyzed by PCR and droplet digital PCR. The results showed that soil contamination with sulfamethoxazole had no significant effect on fungal diversity after 120 days (P>0.05) whereas bacterial diversity was significantly reduced (P<0.05). The microbial community structure of the contaminated soil changed significantly, with the dominant bacterial and fungal genera being significantly different from the control soil. Sulfamethoxazole contamination resulted in an increase in ARG diversity, and the abundance of the sulfonamide resistance gene sul1 increased significantly (P<0.05). However, the abundance of the sulfonamide resistance gene sul2, the quinolone resistance genes floR and cmlA1, and the tetracycline resistance genes tet(34), tetG2, tetG1,tetM, and tetA/P did not show significant changes in the contaminated soil (P>0.05).

Genome-wide analysis of Cushion willow provides insights into alpine plant divergence in a biodiversity hotspot.

The Hengduan Mountains (HDM) biodiversity hotspot exhibits exceptional alpine plant diversity. Here, we investigate factors driving intraspecific divergence within a HDM alpine species Salix brachista (Cushion willow), a common component of subnival assemblages. We produce a high-quality genome assembly for this species and characterize its genetic diversity, population structure and pattern of evolution by resequencing individuals collected across its distribution. We detect population divergence that has been shaped by a landscape of isolated sky island-like habitats displaying strong environmental heterogeneity across elevational gradients, combined with population size fluctuations that have occurred since approximately the late Miocene. These factors are likely important drivers of intraspecific divergence within Cushion willow and possibly other alpine plants with a similar distribution. Since intraspecific divergence is often the first step toward speciation, the same factors can be important contributors to the high alpine species diversity in the HDM.

The impact of DO and salinity on microbial community in poly(butylene succinate) denitrification reactors for recirculating aquaculture system wastewater treatment.

The interactions between environmental factors and bacterial community shift in solid-phase denitrification are crucial for optimum operation of a reactor and to achieve maximum treatment efficiency. In this study, Illumina high-throughput sequencing was applied to reveal the effects of different operational conditions on bacterial community distribution of three continuous operated poly(butylene succinate) biological denitrification reactors used for recirculating aquaculture system (RAS) wastewater treatment. The results indicated that salinity decreased OTU numbers and diversity while dissolved oxygen (DO) had no obvious influence on OTU numbers. Significant microbial community composition differences were observed among and between three denitrification reactors under varied operation conditions. This result was also demonstrated by cluster analysis (CA) and detrended correspondence analysis (DCA). Hierarchical clustering and redundancy analysis (RDA) was performed to test the relationship between environmental factors and bacterial community compositions and result indicated that salinity, DO and hydraulic retention time (HRT) were the three key factors in microbial community formation. Besides, Simplicispira was detected under all operational conditions, which worth drawing more attention for nitrate removal. Moreover, the abundance of nosZ gene and 16S rRNA were analyzed by real-time PCR, which suggested that salinity decreased the proportion of denitrifiers among whole bacterial community while DO had little influence on marine reactors. This study provides an overview of microbial community shift dynamics in solid-phase denitrification reactors when operation parameters changed and proved the feasibility to apply interval aeration for denitrification process based on microbial level, which may shed light on improving the performance of RAS treatment units.

Simultaneous ammonia and nitrate removal in an airlift reactor using poly(butylene succinate) as carbon source and biofilm carrier.

In this study, an airlift inner-loop sequencing batch reactor using poly(butylene succinate) as the biofilm carrier and carbon source was operated under an alternant aerobic/anoxic strategy for nitrogen removal in recirculating aquaculture system. The average TAN and nitrate removal rates of 47.35±15.62gNH4-Nm(-3)d(-1) and 0.64±0.14kgNO3-Nm(-3)d(-1) were achieved with no obvious nitrite accumulation (0.70±0.76mg/L) and the dissolved organic carbon in effluents was maintained at 148.38±39.06mg/L. Besides, the activities of dissimilatory nitrate reduction to ammonium and sulfate reduction activities were successfully inhibited. The proteome KEGG analysis illustrated that ammonia might be removed through heterotrophic nitrification, while the activities of nitrate and nitrite reductases were enhanced through aeration treatment. The microbial community analysis revealed that denitrifiers of Azoarcus and Simplicispira occupied the dominate abundance which accounted for the high nitrate removal performance. Overall, this study broadened our understanding of simultaneous nitrification and denitrification using biodegradable material as biofilm carrier.

Biological denitrification using poly(butylene succinate) as carbon source and biofilm carrier for recirculating aquaculture system effluent treatment.

Nitrate removal is essential for the sustainable operation of recirculating aquaculture system (RAS). This study evaluated the heterotrophic denitrification using poly(butylene succinate) as carbon source and biofilm carrier for RAS wastewater treatment. The effect of varied operational conditions (influent type, salinity and nitrate loading) on reactor performance and microbial community was investigated. The high denitrification rates of 0.53 ± 0.19 kg NO3(-)-N m(-3) d(-1) (salinity, 0‰) and 0.66 ± 0.12 kg NO3(-)-Nm(-3) d(-1) (salinity, 25‰) were achieved, and nitrite concentration was maintained below 1mg/L. In addition, the existence of salinity exhibited more stable nitrate removal efficiency, but caused adverse effects such as excessive effluent dissolved organic carbon (DOC) and dissimilation nitrate reduce to ammonia (DNRA) activity. The degradation of PBS was further confirmed by SEM and FTIR analysis. Illumina sequencing revealed the abundance and species changes of functional denitrification and degradation microflora which might be the primary cause of varied reactor performance.