Effects of long-term fertilizer practices on rhizosphere soil nitrogen mineralization in the double-cropping rice field.

Nitrogen (N) was an important indictor in change of soil fertility, which was closely related with N mineralization process. However, there is still need to further study on how rhizosphere soil N mineralization in paddy field response to different fertilizer management. Therefore, the influence of long-term (37-years) fertilizer regime on rhizosphere soil N mineralization, ammonification and nitrification rates, and its relationship under the double-cropping paddy field in southern of China were investigated in this study. The field experiment included following fertilizer regimes: inorganic fertilizer alone (MF), rice straw and inorganic fertilizer (RF), 30% organic manure and 70% inorganic fertilizer (OM), and no application of any fertilizer as a control (CK). The result indicated that rhizosphere soil organic carbon (SOC), total N, NO3 -N, and NH4 -N contents in paddy field with OM and RF treatments were increased. The result showed that rhizosphere soil NO2 - -N and mineral N contents with OM and RF treatments were increased, and the order of soil NO2 - -N and mineral N contents with all fertilizer treatments was showed as OM > RF > MF > CK. This result proved that soil aerobic and anaerobic N mineralization rates in paddy field with OM and RF treatments were higher than that of CK and MF treatments. Compared with MF treatment, soil ammonification rate with RF and OM treatments increased by 45.16% and 67.74%, soil nitrification rate with RF and OM treatments increased by 45.71% and 77.14%, respectively. There had significantly positively correlation between soil net mineralization, nitrification rate and SOC, total N contents. As a result, applied with rice straw and organic manure was a good measure to improve soil N mineralization in the double-cropping rice field.

Effects of different short-term tillage managements on rhizosphere soil autotrophic CO2 -fixing bacteria in a double-cropping rice paddy field.

Soil autotrophic bacteria community plays an important role in carbon (C) cycling process in soil, but there is still limited information about how the rhizosphere soil microbe that drives this process respond to combined application of tillage with crop residue incorporation managements under a double-cropping rice (Oryza sativa L.) paddy field in southern China. Therefore, the 6-years short-term tillage treatment on rhizosphere soil autotrophic bacteria community [RubisCO gene (cbbL)] under the double-cropping rice paddy field in southern China was studied using the high-throughput sequencing method in the present article. The field experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT) and rotary tillage with all crop residues removed as a control (RTO). The results showed that abundance, composition and activity of rhizosphere soil cbbL-carrying bacteria were obviously influenced by application of different tillage treatments. The rhizosphere soil abundant cbbL and 16S rRNA genes as well as RubisCO activity with CT, RT and NT treatments were higher than that of RTO treatment. The cbbL sequences in rhizosphere soil with CT, RT and NT treatments mainly included Azoarcus_sp._KH33C, Ralstonia_pickettii, Thermomonospora_curvata, Variovorax_paradoxus and uncultured_proteobacterium. Meanwhile, the results indicated that cbbL-carrying bacterial composition was significantly affected by soil organic carbon, microbial biomass carbon, dissolved organic carbon contents and soil bulk density. There had an obvious difference in characteristics of rhizosphere soil autotrophic bacteria community between CT, RT, NT treatments and RTO treatment. Therefore, it was a beneficial practice for improving rhizosphere soil autotrophic bacteria community in the double-cropping rice paddy field in southern China by combined application of tillage with crop residue incorporation practices.

Effects of short-term soil tillage practice on activity and community structure of ammonia-oxidizing bacteria and archaea under the double-cropping rice field.

AIMS: The potential nitrification activity (PNA), population size and community composition of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in paddy soil from a short-term (5 years) tillage field experiment conducted at tillering stage of late rice were investigated using the shaken slurry method and quantitative real-time polymerase chain reaction. METHODS AND RESULTS: The experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue returning (NT) and rotary tillage with all crop residues removed as a control (RTO). The results showed that PNA in paddy soil of CT, RT and NT treatments was higher than that of RTO treatment, and the abundance of AOA and AOB was much higher in paddy soil of CT, RT and NT treatments than RTO treatment. Meanwhile, PNA and the abundance of AOB and AOA in paddy soil were greatly enhanced by combined application of tillage and crop residue, whereas PNA and the abundance of AOB and AOA in paddy soil were decreased by combined application of no-tillage and crop residue. Moreover, PNA was closely correlated with the abundance and community structure of AOB rather than AOA. The results also showed that PNA and the population sizes of AOB and AOA in crop incorporation treatments were higher than that of crop residue removed treatment. Cluster and redundancy analyses indicated that crop residue effect played a more important role in shaping AOA community structure compared to short-term tillage management. CONCLUSIONS: The results indicated that AOB rather than AOA functionally dominated ammonia oxidation in the double-cropping rice paddy soil, the activities of AOB and AOA were increased and the community structure was also changed under the combination of conventional tillage, rotary tillage and crop residue condition. SIGNIFICANCE AND IMPACT OF STUDY: The activity and community structure of AOB and AOA, which were affected by the combination of tillage and crop residue managements, play an important role in cycling of nitrogen.

Deep learning segmentation model for automated detection of the opacity regions in the chest X-rays of the Covid-19 positive patients and the application for disease severity

PurposeThe pandemic of Covid-19 has caused tremendous losses to lives and economy in the entire world. The machine learning models have been applied to the radiological images of the Covid-19 positive patients for disease prediction and severity assessment. However, a segmentation model for detecting the opacity regions like haziness, ground-glass opacity and lung consolidation from the Covid-19 positive chest X-rays is still lacking. MethodsThe recently published collection of the radiological images for a rural population in United States had made the development of such a model a possibility, for the high quality images and consistent clinical measurements. We manually annotated 221 chest X-ray images with the lung fields and the opacity regions and trained a segmentation model for the opacity region using the Unet framework and the Resnet18 backbone. In addition, we applied the percentage of the opacity region over the area of the total lung fields for predicting the severity of patients. ResultsThe model has a good performance regarding the overlap between the predicted and the manually labelled opacity regions. The performance is comparable for both the testing data set and the validation data set which comes from very diverse sources. However, careful manual examinations by experienced radiologists show mistakes in the predictions, which could be caused by the anatomical complexities. Nevertheless, the percentage of the opacity region can predict the severity of the patients well in regards to the ICU admissions and mortality. ConclusionIn view of the above, our model is a successful first try in the development of a segmentation model for the opacity regions for the Covid-19 positive chest X-rays. However, additional work is needed before a robust model can be developed for the ultimate goal of the implementations in the clinical setting. Model and supporting materials can be found in https://github.com/haimingt/opacity_segmentation_covid_chest_X_ray.

Microbial carbon source utilization in rice rhizosphere and nonrhizosphere soils with short-term manure N input rate in paddy field.

Carbon (C) plays a vital role in regulating soil nutrient cycling and increasing soil microbial community, but there is still limited information on how C source utilization characteristics responds to soil physical and chemical properties changes under double-cropping rice (Oryza sativa L.) paddy field in southern China. Therefore, the effects of different short-term manure nitrogen (N) input rate managements on C source utilization characteristics in rice rhizosphere and non-rhizosphere soils under double-cropping rice field in southern China were studied by using 18O-H2O method. Therefore, a field experiment were established in Ningxiang city of Hunan Province, and five different fertilizer treatments were applied: (1) 100% N of chemical fertilizer (M0), (2) 30% N of organic manure and 70% N of chemical fertilizer (M30), (3) 50% N of organic manure and 50% N of chemical fertilizer (M50), (4) 100% N of organic manure (M100), and (5) without N fertilizer input as control (CK). The results showed that soil microbial biomass C content, soil microbial growth rate, and soil microbial basal respiration with application of organic manure treatments (M30, M50, M100) were significantly higher (p < 0.05) than that of CK treatment. And the soil C utilization efficiency with M0 treatment were significantly higher (p < 0.05) than that of M100 treatment. Compared with CK and M0 treatments, the metabolic capacity of soil microorganisms to exogenous C sources with M30, M50 and M100 treatments were increased. The largest types of exogenous C source was carboxylic acids, followed by amino acid and carbohydrate, and complex compounds was the smallest. The RDA analysis results indicated that fertilizer treatments significantly changed the utilization characteristics of soil microorganisms to exogenous C sources. As a result, this study found that characteristics of soil C source utilization were significantly affected by different short-term manure N input rate managements.

Simultaneous determination of five nucleosides in Houtoujun Tablets by RP-HPLC / 中成药

AIM To establish an RP-HPLC method for the simultaneous content determination of five nucleosides in Houtoujun Tablets (mycelia of Hericium erinaceum).METHODS The analysis of aqueous extract of this drug was performed on a 26 ℃ thermostatic Zorbax SB-Aq C18 column (250 mm ×4.6 mm,5 μm),with the mobile phase comprising of methanol-0.1％ phosphoric acid flowing at 0.5 mL/min in a gradient elution manner,and the detection wavelength was set at 260 nm.RESULTS Cytidine,adenine,uridine,adenosine and guanosine showed good linear relationships within the ranges of 0.007-0.169,0.005-0.115,0.032-0.797,0.032-0.792 and 0.004-0.103 μg,whose average recoveries (n =6) were 99.4％ (RSD =2.0％),98.3％ (RSD =1.8％),98.0％ (RSD =2.8％),101.4％ (RSD =1.9％) and 101.7％ (RSD =1.2％),respectively.CONCLUSION The contents of five nucleosides in Houtoujun Tablets from different manufacturers exhibit obvious differences,to which we should pay attention.

Therapeutic Observation of Moxibustion plus Anus-lifting Exercise in Preventing Hemorrhoids Relapse / 上海针灸杂志

Objective To observe the clinical efficacy of moxibustion plus anus-lifting exercise in preventing hemorrhoids relapse.Method Seventy eligible patients with mixed hemorrhoids whose symptoms had been released by conservative treatment were randomized into a treatment group and a control group, 35 cases in each group. The treatment group was intervened by moxibustion plus anus-lifting exercise, while the control group only practiced anus-lifting exercise. The intervention was conducted successively for 4 weeks. Symptoms including hematochezia, bearing-down pain, prolapse, and size of hemorrhoid were scored in the 1st, 2nd, 3rd, and 4th treatment weeks as well as the 4th week after the intervention, meanwhile, the relapse rates of the above symptoms were observed.Result In the 3rd treatment week, there were significant differences in comparing the scores of prolapse, bearing-down pain, and hemorrhoid size between the two groups (allP<0.05); in the 4th treatment week and the 4th week after the intervention, there were significant differences in comparing the scores of hematochezia, prolapse, bearing-down pain and hemorrhoid size between the two groups (allP<0.05); in the 4th week after the intervention, there were significant differences in comparing the relapse rates of hematochezia, bearing-down pain, prolapse and hemorrhoid size between the two groups (P<0.05).Conclusion Moxibustion plus anus-lifting exercise can produce a significant efficacy in preventing the hemorrhoids relapse.

Study on Content Dynamic Changes of Three Water-soluble Flavonoids in Isodon Lophanthoides / 中国药师

Objective:To establish an HPLC method for the simultaneous determination of viceninⅡ, isoschaftoside and schafto-side in Isodon lophanthoides, and analyze their content dynamic changes. Methods:The HPLC system consisted of a Phenomenex luna C18(250 mm ×4.6 mm, 5 μm)column and a solution system of methanol and 0.5% formic acid with gradient elution, the flow rate was 0. 8 ml·min-1 and the detection wavelength was 334 nm at the column temperature of 25℃and the injection volume was 10 μl. Results:The linear range of viceninⅡ, isoschaftoside and schaftoside was 0.130-3.110 μg(r =0.999 8), 0.180-4.540 μg(r =0.999 9) and 0.080-1.970 μg(r =0. 9999), respectively. The average recovery was 96.8% (RSD =1.9%), 99.2% (RSD =1. 6%) and 97. 1% (RSD=1. 6%) (n=6), respectively. The above three kinds of water-soluble flavonoids from seedling stage to significant accumulation, isoschaftoside and schaftoside reached the highest value in March and August, the content of VitexinⅡ in January and April tends to be stable, in May began to increase gradually, reached the maximum value in August, then began to de-crease. Conclusion:With the contents of water-soluble flavonoids as the indicators, the best harvest time of Isodon lophanthoides is March and August, and the quality of the medicinal materials harvested in August is the best.