Plant diversity increases spatial stability of aboveground productivity in alpine grasslands.

Plant diversity can significantly affect the grassland productivity and its stability. However, it remains unclear how plant diversity affects the spatial stability of natural grassland productivity, especially in alpine regions that are sensitive to climate change. We analyzed the interaction between plant (species richness and productivity, etc.) and climatic factors (precipitation, temperature, and moisture index, etc.) of alpine natural grassland on the Qinghai-Tibetan Plateau. In addition, we tested the relationship between plant diversity and spatial stability of grassland productivity. Results showed that an increase in plant diversity significantly enhanced community productivity and its standard deviation, while reducing the coefficient of variation in productivity. The influence of plant diversity on productivity and the reciprocal of productivity variability coefficient was not affected by vegetation types. The absolute values of the regression slopes between climate factors and productivity in alpine meadow communities with higher plant diversity were smaller than those in alpine meadow communities with lower plant diversity. In other words, alpine meadow communities with higher plant diversity exhibited a weaker response to climatic factors in terms of productivity, whereas those with lower plant diversity showed a stronger response. Our results indicate that high plant diversity buffers the impact of ambient pressure (e.g., precipitation, temperature) on alpine meadow productivity, and significantly enhanced the spatial stability of grassland productivity. This finding provides a theoretical basis for maintaining the stability of grassland ecosystems and scientifically managing alpine grasslands under the continuous climate change.

Warming-driven indirect effects on alpine grasslands: short-term gravel encroachment rapidly reshapes community structure and reduces community stability.

The community stability is the main ability to resist and be resilient to climate changes. In a world of climate warming and melting glaciers, alpine gravel encroachment was occurring universally and threatening hillside grassland ecosystem. Gravel encroachment caused by climate warming and glacial melting may alter community structure and community stability in alpine meadow. Yet, the effects of climate warming-induced gravel encroachment on grassland communities are unknown. Here, a 1-year short-term field experiment was conducted to explore the early stage drive process of gravel encroachment on community structure and stability at four different gravel encroachment levels 0%, 30%, 60%, and 90% gravel coverage at an alpine meadow on the Qinghai Tibetan Plateau, by analyzing the changes of dominant species stability and species asynchrony to the simulated gravel encroachment processes. Gravel encroachment rapidly changed the species composition and species ranking of alpine meadow plant community in a short period of time. Specifically, community stability of alpine meadow decreased by 61.78-79.48%, which may be due to the reduced dominant species stability and species asynchrony. Species asynchrony and dominant species stability were reduced by 2.65-17.39% and 46.51-67.97%, respectively. The results of this study demonstrate that gravel encroachment presents a severe negative impact on community structure and stability of alpine meadow in the short term, the longer term and comprehensive study should be conducted to accurate prediction of global warming-induced indirect effects on alpine grassland ecosystems.

Natural compensation mechanism of soil water infiltration through decayed roots in semi-arid vegetation species.

In arid and semi-arid areas, unsuitable afforestation programs may cause soil water deficit and even, in some cases, deep-soil desiccation and the subsequent death of part of the vegetation. However, the benefits of preferential flow through decayed root channels for supplying water in the dried soil layers are rarely evaluated. This study examines the effects of root channels on soil water content (SWC) and infiltration (initial and steady-state) in two planted species with high drought tolerance, namely: Korshinsk peashrub (Caragana korshinskii Kom.), and red plum apricot (Armeniaca vulgaris Lam.), using bare land as control site and published data from alfalfa (Medicago sativa L.) plots to refine results analysis. The infiltration rates were measured using a double-ring infiltrometer in areas with alive and decayed roots; and methylene blue was used to trace the pathways of water flow. The highest SWC appeared in the Korshinsk peashrub land, whereas the alfalfa grassland had the lowest SWC; and the differences of SWC among treatments were significant at all soil layers. Korshinsk peashrub had the highest steady infiltration rates, which were about 23% and 83% higher than those rates measured in the fruit tree plantation and alfalfa grasslands, respectively. The steady infiltration rates were significantly and positively correlated with the average root diameter and area. Within the same species, the decayed root plots significantly increased the soil water infiltration capacity compared to the alive root plots. Considering the water scarcity conditions of the study area, the preferential flow formed through decomposed roots was conducive to soil water supplement, appearing as a natural compensation mechanism caused by dead vegetation. Our findings contribute to a better understanding of soil water infiltration during root decay of the plants in water-limited ecosystems, and how this dynamic replenishes soil moisture and alleviates soil desiccation.

A novel synthesis of oleophylic Fe2O3/polystyrene fibers by γ-Ray irradiation for the enhanced photocatalysis of 4-chlorophenol and 4-nitrophenol degradation.

Photocatalytic degradation by efficient and easy recyclable semiconductor-catalysts is an ideal way to solve the environmental problem. A series of Fe2O3/Polystyrene (Fe2O3/PS) composite fibers with hydrophobic property were obtained by the electrospinning and γ-Ray irradiation methods. The γ-Ray irradiation treatment not only formed steady micro-nano construction of nanoparticles and fiber, but also reduced the hydroxyl group on Fe2O3 surface. The high photocatalytic efficiencies of Fe2O3/PS fiber were discovered with the high content of 4-chlorophenol (4-CP) and 4-nitrophenol (4-NP), due to the synergetic effect of adsorption and degradation. The suitable adsorption capacity of Fe2O3/PS could promote the utilization of the generated hydroxyl radical(OH) to directly oxidize the adsorbed pollutant molecules. Additionally, the photocatalytic activities for 4-CP and 4-NP still reached 80% and 75% in the 6th cycling and the composite fiber exhibited the good recyclability, which has the application development prospect for wastewater treatment. The mechanism of 4-CP and 4-NP decomposition was verified. Hence, the gained results could provide some insights into phenol degradation over the multifunctional and efficient catalyst.

Intervention efficacy of perioperative antimicrobial use in arthroscopic surgery / 中国感染控制杂志

Objective To investigate perioperative antimicrobial prophylaxis in arthroscopic surgery in a hospital before and after intervention,evaluate intervention efficacy,and provide evidence for the rational clinical antimicro-bial application.Methods From August 2012,measures were taken to intervene perioperative antimicrobial use, perioperative antimicrobial use and surgical site infection(SSI)in 312 patients undergoing arthroscopic surgery be-tween September 2011 and August 2013 were retrospectively surveyed.Results A total of 312 patients were investi-gated,pre-and post-intervention were 150 and 162 cases respectively,SSI rates were both 0 before and after inter-vention. Antimicrobial usage rate after intervention was lower than before intervention (26.54% vs 100.00% ,χ2=1.781,P<0.001). Irrational antimicrobial use dropped obviously;average expense of antimicrobial agents dropped from (1165.69±756.33)yuan (RMB)before intervention to (32.71 ±119.29)yuan (RMB)after intervention (t= 3.330,P<0.001).Conclusion Perioperative antimicrobial usage rate in arthroscopic surgery at this hospital decreased significantly after intervention,rational use of antimicrobial agents has improved,SSI rate still remains zero.

Survey on prevalence of healthcare-associated infection in Xiangya Hospital in 15 years / 中国感染控制杂志

Objective To investigate the prevalence rate of healthcare-associated infection(HAI)in Xiangya Hospital,and provide reference for preventing and controlling HAI.Methods The cross sectional surveys on preva-lence rates of HAI,cross-sectional antimicrobial use,and bacterial detection among all hospitalized patients on the given days in 2000-2014 (except 2006)were carried out by combination of bedside investigation and medical record reviewing.Results The prevalence rates of HAI in 2000-2014 decreased from 6.30% to 3.91%,difference was statistically significant (χ2 = 35.14,P < 0.001 );prevalence rates of community-associated infection(CAI)were 15.61%-15.76%,there was no significant difference among each year.General intensive care unit (ICU)had the highest prevalence rate;respiratory tract was the most common site of both HAI and CAI;urinary catheterization rate showed a decreased tendency,arteriovenous catheterization rate showed a increased tendency,difference were both significant(χ2 = 5.21,96.24,respectively,both P <0.001).In 2008 - 2014,pathogenic detection rates for specimens from patients receiving therapeutic antimicrobial agents were 36.37%-44.51%,from patients with HAI were 34.00%-44.99%,detection rate of pathogens causing HAI were 41.57%-68.48%,all showed a increased tendency,difference was significant (χ2 = 22.78,10.03,26.49,respectively,all P < 0.001 ).Gram-negative bacteria were the main pathogens causing infection;both cross sectional and combination antimicrobial usage rates declined (P < 0.05 ).Conclusion Prevention and control of HAI,and antimicrobial management has achieved preliminary success,prevalence rate of HAI and cross sectional antimicrobial usage rate declined obviously,the main pathogen is gram-negative bacteria,and the major infection site is lower respiratory tract.

Study on intervention in central line-associated bloodstream infection in intensive care units / 中国感染控制杂志

Objective To evaluate the effect of evidence-based bundle intervention strategy on reducing the inci-dence of central line-associated bloodstream infection (CLABSI).Methods Prospective and multicenter study was adopted,patients admitted to 54 intensive care units (ICUs)of 41 hospitals and with central venous catheters (CVCs)between October 1 ,2013 and September 30,2014 were monitored .Baseline data between October 2013 and March 2014 were collected as pre-intervention data;from April to September 2014,the participated hospitals performed intervention strategy,post-intervention data were compared with pre-intervention data.Results The usage rate of CVCs before and after intervention was significantly different (44.18% vs 44.63%,χ2 =5.526,P =0.019).Incidence of CLABSI before and after intervention was not significantly different(RR ,0.82[95%CI ,0.59-1 .13],P =0.10).Constituent ratio of catheter insertion sites between pre-and post-intervention was significantly different (χ2 =76.264,P <0.001),femoral vein catheterization rate as well as proportion of two and above catheter insertion sites after intervention decreased(17.25% VS 13.72%;2.27% VS 1 .44%,respectively);hand hygiene implementation rate and accuracy rate after intervention were both higher than before intervention (79.73% vs 76.14%,P <0.001 ;91 .47% vs 74.26%,P <0.001 ,respectively);constituent ratio of skin disinfectant applica-tion before and after intervention was significantly different(χ2 =3.861 ,P <0.001 ),proportion of chlorhexidine ethanol increased (29.62% VS 50.56%);except daily assessment and record,compliance to other prevention and control measures before and after intervention were all significantly different(all P <0.001);utilization rate of max-imal sterile barrier,qualified rate of dressing of operators,and port disinfection were all significantly enhanced. Conclusion Bundle intervention in intubation and maintenance are implemented effectively,but intervention effect on CLABSI needs further study.

[Application of video endoscopic inguinal lymphadenectomy in radical vulvectomy for carcinoma].

OBJECTIVE: To evaluate the feasibility and safety of applying video endoscopic inguinal lymphadenectomy via hypogastric subcutaneous approach (VEIL-H) in the treatment of vulvar carcinoma. METHODS: From September 2009 to December 2012, 15 patients with vulvar carcinoma underwent VEIL-H plus radical vulvectomy at many participating hospitals. RESULTS: All were treated surgically. Two of them underwent laparoscopic pelvic lymphadenectomy (LPL) upon the positive results of parotid operations with frozen section. The mean operative duration of VEIL-H (bilateral groin) were (80.8 ± 2.9) minutes. The mean total volume of blood loss in VEIL was (5.5 ± 0.4) ml, the mean drainage duration (6 ± 2) days and the average postoperative hospitalization (11 ± 4) days. The mean follow-up period was 13.0 months. One patient suffered local recurrence at Month 2 postoperation. CONCLUSION: VEIL-H is both feasible and safe in inguinal lymphadenectomy.

Utilization of microRNAs with decreased expression levels in response to X-ray irradiation for fine-tuning radiation-controlled gene regulation.

We previously developed a promoter that was responsive to radiation by randomly combining cis-elements of transcription factors that are activated in response to radiation in prostate cancer cells. The promoter enhanced the expression of the luciferase gene linked downstream by more than 10-fold 12 h after X-ray irradiation at 10 Gy. However, without radiation, it still significantly drove its expression. To suppress expression while retaining its enhancement in response to radiation, we focused our attention on microRNAs (miRNAs). miRNAs are a group of non-coding RNAs approximately 22 nucleotides long that control gene expression by binding to a target sequence residing on the 3'-untranslated region (3'UTR) of a target gene. We identified 8 miRNAs that were downregulated in response to X-ray irradiation, and inserted artificial target sequences composed of randomly combined complementary sequences into 3 representative miRNAs into the 3'UTR of the luciferase gene. The target sequences suppressed the expression, and released the expression, after X-ray irradiation, as expected. When we combined an artificial target sequence with the radiation-responsive promoter, it resulted in a clear-cut gene regulation of expression that was greater than that induced by the promoter alone.

Illness severity and prognosis assessment with acute physiology and chronic health evaluation II for patients after cardiovascular surgery / 中南大学学报(医学版)

OBJECTIVE@#To evaluate illness severity and to assess the prognosis with acute physiology and chronic health evaluation II (APACHE II) for patients after cardiovascular surgery.@*METHODS@#APACHE II scores of 234 patients in the cardiac surgical intensive care unit (CSICU) were calculated, and the actual mortality and the predicted mortality were obtained based on the score.@*RESULTS@#The APACHE II score of the 234 patients was 14.22±6.77. The difference in the APACHE II score between the survivors, the patients with complications and the death group was significant; the difference in the APACHE II score between patients with different preoperative cardiac functions was significant; the detention time in the CSICU was positively related to APACHE II scores; and the ROC area under the curve of APACHE II was 0.991±0.006. With the predicted rate >30% as the standard for death, sensitivity of APACHE II score for mortality risk prediction was 80.00%, specificity was 99.12%, and the accuracy was 98.72%. According to the score, we divided the patients into 3 groups (20 points), forecast mortality in the >20 point group was in the 95% confidence interval of actual mortality.@*CONCLUSION@#APACHE II is a good index for illness severity and prognosis assessment for patients after cardiovascular surgery.