Biochar-compost addition benefits Phragmites australis growth and soil property in coastal wetlands.

Salinity stress is common for plants growing in coastal wetlands. The addition of biochar in the soil may alleviate the negative effect of salinity through its unique physicochemical properties. To test this, we conducted a greenhouse experiment where the cosmopolitan wetland plant Phragmites australis was subjected to four salinity treatments (0, 5, 10 and 15‰) and three biochar treatments (no biochar addition, with biochar addition and with biochar-compost addition, both biochar and compost were made from P. australis) in a factorial design. Both biochar addition and biochar-compost addition to the substrate enhanced belowground mass of P. australis, application of biochar-compost significantly increased total mass by 35.5% and net photosynthesis rate of P. australis by 51.4%. Both biochar addition and biochar-compost addition significantly increased soil organic carbon content by 62.9% and 31.7%, respectively, but decreased soil ammonium nitrogen content. In the saline soil, application of the mixture of biochar-compost had a strong, and positive effect on the growth of P. australis, compared to biochar alone. Therefore, incorporation of biochar and compost might be an appropriate approach to improve the productivity of P. australis growing in coastal wetlands, where soil salinity is a common environmental stress.

Biochar addition affects root morphology and nitrogen uptake capacity in common reed (Phragmites australis).

Nitrogen (N) is a key factor that limits plant growth in most terrestrial ecosystems, and biochar reportedly improves soil characteristics and grain yields. However, the effects of biochar on plant N uptake in wetland ecosystems and the underlying mechanisms of these effects remain unclear. Therefore, our study sought to characterise the effects of biochar addition on Phragmites australis N absorption rates at two different N deposition conditions [30 and 60 kg N hm-2 yr-1; i.e., "low" and "high" N treatments, respectively]. Our results demonstrated that biochar significantly promoted root biomass growth in P. australis in the high N treatment group. In contrast, the low N treatment group exhibited an increased proportion of fine roots and a decrease in the average P. australis root diameter. The N absorption rate of P. australis in the low N treatment group significantly increased with biochar addition and ammonium N became the preferred N source. The absorption rates of both ammonium and nitrate N were negatively correlated with the average P. australis root diameter. Therefore, our findings indicate that biochar may affect the N uptake strategy of P. australis by altering root morphogenesis, thereby providing new insights into potential restoration strategies for wetland vegetation.

Biochar rhizosphere addition promoted Phragmites australis growth and changed soil properties in the Yellow River Delta.

Biochar addition can enhance plant growth and change soil physicochemical properties in saline soil. However, it is unclear whether the positioning of biochar additions (e.g., rhizosphere addition and surface addition) alters such impacts and whether such positioning effects interact with salinity levels. In the Yellow River Delta, China, we carried out a field experiment in which biochar was not added (control) or was added to the soil surface (surface addition) or to the soil at the rhizosphere position (rhizosphere addition) of Phragmites australis in three sites with different salt levels (1‰ - low, 5‰ - medium and 10‰ - high). Rhizosphere addition of biochar significantly improved the growth of P. australis, especially its fine root mass. Both rhizosphere addition and surface addition of biochar significantly decreased nitrate nitrogen content and electrical conductivity, and the inhibitory effects were more effective at the sites with medium and high salt levels in 2018. Structural equation modeling showed that biochar addition could directly increase the fine root mass of P. australis by decreasing the soil electrical conductivity, further improving the total mass of P. australis. Overall, rhizosphere addition of biochar is a better choice for improving the productivity of P. australis in saline soil and is beneficial to P. australis wetland restoration in the Yellow River Delta. Long-term field research is needed to better understand the effect and mechanism of biochar application.

Soil resource heterogeneity competitively favors an invasive clonal plant over a native one.

Soil resource heterogeneity can affect plant growth and competitive ability. However, little is known about how soil resource heterogeneity affects competitive interactions between invasive and native plants. We conducted an experiment with an invasive clonal plant Alternanthera philoxeroides and a coexisting native one Alternanthera sessilis. The experiment was a randomized design with three factors, i.e. two species (A. philoxeroides and A. sessilis), two interspecific competition treatments (with and without) and five soil treatments (three homogeneous treatments and two small-scale heterogeneous treatments consisting of two patches of 10 cm × 15 cm and with different initial planting positions). Irrespective of competition, increasing soil resource availability increased the growth of A. philoxeroides. Increasing soil resource availability also increased the growth of A. sessilis without competition, but had no impact with competition. Irrespective of competition, soil resource heterogeneity increased biomass and ramet production of A. philoxeroides, and such effects were independent of initial planting position. For A. sessilis, however, soil resource heterogeneity only increased ramet production when the initial plant was grown in the low-resource patch without competition. Our results suggest that both high soil resource availability and small-scale soil resource heterogeneity can increase the relative competitive ability of the invasive plant A. philoxeroides when grown with its native congener A. sessilis. These findings may partly explain the invasion success of this clonal species in area with high soil resource availability and heterogeneity caused by e.g. nitrogen deposition, fertilization and disturbance.

Effects of arbuscular mycorrhizal fungi and soil nutrient addition on the growth of Phragmites australis under different drying-rewetting cycles.

The frequency of soil drying-rewetting cycles is predicted to increase under future global climate change, and arbuscular mycorrhizal fungi (AMF) are symbiotic with most plants. However, it remains unknown how AMF affect plant growth under different frequencies of soil drying-rewetting cycles. We subjected a clonal wetland plant Phragmites australis to three frequencies of drying-rewetting cycles (1, 2, or 4 cycles), two nutrient treatments (with or without), and two AMF treatments (with or without) for 64 days. AMF promoted the growth of P. australis, especially in the 2 cycles of the drying-rewetting treatment. AMF had a significant positive effect on leaf mass and number of ramets in the 2 cycles of the drying-rewetting treatment with nutrient addition. In the 2 cycles of drying-rewetting treatment without nutrient addition, AMF increased leaf area and decreased belowground to aboveground biomass ratio. These results indicate that AMF may assist P. australis in coping with medium frequency of drying-rewetting cycles, and provide theoretical guidance for predicting how wetland plants respond to future global climate change.

Computer-assisted virtual preoperative planning in orthopedic surgery for acetabular fractures based on actual computed tomography data.

Acetabular fractures have always been very challenging for orthopedic surgeons; therefore, appropriate preoperative evaluation and planning are particularly important. This study aimed to explore the application methods and clinical value of preoperative computer simulation (PCS) in treating pelvic and acetabular fractures. Spiral computed tomography (CT) was performed on 13 patients with pelvic and acetabular fractures, and Digital Imaging and Communications in Medicine (DICOM) data were then input into Mimics software to reconstruct three-dimensional (3D) models of actual pelvic and acetabular fractures for preoperative simulative reduction and fixation, and to simulate each surgical procedure. The times needed for virtual surgical modeling and reduction and fixation were also recorded. The average fracture-modeling time was 45 min (30-70 min), and the average time for bone reduction and fixation was 28 min (16-45 min). Among the surgical approaches planned for these 13 patients, 12 were finally adopted; 12 cases used the simulated surgical fixation, and only 1 case used a partial planned fixation method. PCS can provide accurate surgical plans and data support for actual surgeries.

[Pollution Level and Sources of Organic Phosphorus Esters in Airborne PM2.5 in Chengdu City].

Organic phosphorus esters ( OPEs ) in atmospheric PM2.5 in Chengdu city was quantitatively determined by using gas chromatography-mass spectrometry. The distribution characteristic was discussed, back trajectory model and correlation analysis were used to study the sources of OPEs in PM2.5 in Chengdu city. The results showed that the annual average concentration of Σ7OPEs in atmospheric PM2.5 in Chengdu city was 6.46 ng x m(-3) for the urban site and was 9.38 ng x m(-3) for the suburb site. Due to the waste material recycling industries in the suburb area and the perennial dominant wind direction in Chengdu, the concentration of Σ7OPEs at suburb site was higher than that at urban site (P = 0.013). The atmospheric mixed degree influenced the distribution of OPEs in rural and urban area. The source of Σ7OPEs in atmospheric PM2.5 in Chengdu city was mainly from endogenous pollution which was mainly affected by the local sources around the samoling sites. while the contribution of the exogenous pollution was small.

An oxidoreduction potential shift control strategy for high purity propionic acid production by Propionibacterium freudenreichii CCTCC M207015 with glycerol as sole carbon source.

The effects of oxidoreduction potential (ORP) regulation on the process of propionic acid production by Propionibacterium freudenreichii CCTCC M207015 have been investigated. Potassium ferricyanide and sodium borohydride were determined as ORP control agents through serum bottle experiment. In batch fermentation, cell growth, propionic acid and by-products distribution were changed with ORP levels in the range of 0-160 mV. Based on these analysis results, an ORP-shift control strategy was proposed: at first 156 h, ORP was controlled at 120 mV to obtain higher cell growth rate and propionic acid formation rate, and then it was shifted to 80 mV after 156 h to maintain the higher propionic acid formation rate. By applying this strategy, the optimal parameters were obtained as follows: the propionic acid concentration 45.99 g L(-1), productivity 0.192 g L(-1) h(-1), the proportion of propionic acid to total organic acids 92.26 % (w/w) and glycerol conversion efficiency 76.65 %. The mechanism of ORP regulation was discussed by the ratio of NADH/NAD(+), ATP levels, and metabolic flux analysis. The results suggest that it is possible to redistribute energy and metabolic fluxes by the ORP-shift control strategy, and the strategy could provide a simple and efficient tool to realize high purity propionic acid production with glycerol as carbon source.

[Analysis of characteristics of road traffic injuries in Bao'an District, Shenzhen from 2004 to 2011].

OBJECTIVE: To analyze the characteristics of road traffic accidents in Bao'an District, Shenzhen from 2004 to 2011, and to provide scientific basis for the prevention and treatment of traffic accidents. METHODS: The traffic injury cases recorded by Shenzhen traffic police from 2004 to 2011 were analyzed, including the time (year, month, date); the space (crossings and road segments, road type); the injury of patients (injuries, death). RESULTS: A total of 422 730 accidents from road traffic occurred in Bao'an District, Shenzhen from 2004 to 2011, with 63 809 people injured and 2 790 people died, and the mortality ratio was 22.87:1. Traffic accidents occurred in Bao'an District showed an increasing trend, especially in 2010, and the highest number up to 90 358, while the most deaths occurred in 2007, up to 473 people. As to the single month, the highest traffic accident rate was in August, accounting for 9.77% of the total, while the lowest was in February, accounting for 5.39% of the total; mortality rate in December reached 9.02%. As to one single day, the peaks of accidents occurred in two periods: 9:00-11:00 and 15:00-18:00, and 3:00-6:00 had the smallest number. Traffic injuries often occurred in the intersection, straight line, main road and the section only marked marking. CONCLUSION: According to the characteristics of regional traffic injury, we should enhance the populace traffic safe awareness, efficiently arrange the human resources, such as emergency personnel, traffic management personnel, set scientific preventive measures, and modify the emergency system and service mode. All of these are essential measures for the prevention and control of traffic injuries.

[Diagnostic performance of 64-channel multislice computed tomography in assessment of significant coronary artery disease in subjects suspected as acute coronary syndrome and stable angina.].

OBJECTIVE: To evaluate the diagnostic accuracy of 64-channel multislice spiral computed tomography (MSCT) in subjects with presentations suggestive of stable angina or acute coronary syndrome. METHODS: Subjects received both 64-channel MSCT and coronary angiography, from Feb. 2006 to Feb. 2007, were enrolled for retrospective analyses. Results of the quantitative coronary angiography were used as the "Golden criteria", accuracy of 64-channel MSCT were evaluated in the overall sample, as well as in subjects suspected of stable angina and acute coronary syndrome. RESULTS: A total of 120 subjects were enrolled in the analyses. On the patient level, the sensitivity, specificity, and accuracy of 64-channel MSCT in detecting significant stenoses were 92.5%, 50%, and 87.5%, respectively. The overall ROC area under curve was 0.71. On the artery level, sensitivity, specificity, positive predictive value, negative predictive value, and ROC area under curve of 64-channel MSCT were 69.9%, 83.8%, 81.1%, 73.7%, and 0.77, respectively. Further analyses showed the sensitivity, specificity, positive predictive value, negative predictive value, and ROC area under curve of 64-channel MSCT in subjects presenting as stable angina and in subjects presenting as acute coronary syndrome were as follows: 70.2% vs 69.2%, 76.2% vs 86.0%, 74.7% vs 85.6%, 71.9% vs 69.9%, and 0.73 vs 0.78. CONCLUSION: The accuracy rates of 64-channel MSCT in subjects presenting as stable angina and in subjects presenting as acute coronary syndrome were similar.