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[en] By using the fixed monitoring sample sites of two re-vegetation modes in the opencast coal mine dump of Zhongmei Pingsuo as platform, we analyzed the number and the dynamic characteristics of the spatial distribution of all naturally regenerated seedlings in 2010 and 2014, sampled the corresponding soil, and investigated the correlation of two re-vegetation modes and soil quality parameters. Our results indicated that (1) the plant vegetation seedlings of SII site reduced and those of SI site significantly increased, which was opposite to saplings, and in 2014, the number of saplings in SII site substantially increased twice than the number in 2010; (2) from the respective of spatial distribution, the spatial map of seedlings and saplings showed that the their distribution of major species was consistent in 2010 and 2014. The dense and sparse areas in 2010 kept a similar distribution in 2014, which corresponds to the quantity of the species; (3) stepwise linear regression analysis between the survival rates of seedlings and saplings of various species and soil parameters indicated that the survival rate of elm seedlings significantly negatively correlated with soil moisture content and positively correlated with pH, and that the survival rate of locust saplings exhibited an extremely positive correlation to the organic matter content. (author)
[en] Adaptation to environmental changes is crucial for the viability of all organisms. In plants, cysteine proteases (CP) are vital proteolytic enzymes response to complex and volatile environmental factors. Previously, over-expression of a CP gene isolated from Salix matsudana (SmCP) was shown to improve the salt stress tolerance of Arabidopsis thaliana. However, the molecular mechanisms that underlie the enhanced salt stress tolerance of these over-expression lines remain uncharacterized. In this study, the transcriptome of transgenic Arabidopsis SmCP over-expression lines and wild type (WT) control (CT) plants was analyzed by RNA sequencing to identify genes associated with salt tolerance. The abundance level of selected differentially expressed genes was validated by quantitative real-time PCR analysis. The SmCP-transgenic line showed many transcriptomic changes under salt-stress conditions, including genes associated with alterations in the antioxidant environment and ion-transport capacity. Elucidation of the mechanism of salt stress resistance is important for utilization of SmCP for genetic improvement of commercial crops for tolerance to saline soil . (author)
[en] To study the expressions of TIMP-1 and MMP-9 in patients with chronic obstructive pulmonary disease (COPD) complicated with spontaneous pneumothorax, and their correlations with treatment outcomes. Methods: A total of 80 COPD patients complicated with spontaneous pneumothorax treated in our hospital from December 2015 to December 2017. The serum expressions of TIMP-1 and MMP-9 in 80 COPD patients complicated with spontaneous pneumothorax (COPD group) and 52 healthy volunteers (control group) were detected by ELISA. The correlations of TIMP-1 and MMP-9 expressions with arterial blood gas parameters as well as scores of MRC breathlessness scale and St. George’s Respiratory Questionnaire (SGRQ) were analyzed. Results: The serum expressions of TIMP-1 and MMP-9 of COPD group were significantly higher than those of control group (P<0.05), but the two groups had similar MMP-9/TIMP-1 ratios (P>0.05). For COPD group, TIMP-1 expression, MMP-9 expression, MMP-9/TIMP-1, Sa(O2) and p(O2) were not correlated (P>0.05). TIMP-1 expression was significantly positively correlated with MRC scale and SGRQ scores (P<0.05). Sa(O2), p(O2) and MRC scale score of low MMP-9 expression, low TIMP-1 expression and low MMP-9/TIMP-1 group were significantly improved compared with those of high MMP-9 expression, high TIMP-1 expression and high MMP-9/TIMP-1 group (P<0.05). MMP-9 expression, TIMP-1 expression or MMP-9/TIMP-1 was not correlated with improvement of SGRQ score. Pulmonary function improvement (Sa(O2) improvement rate ≥5% and/or p(O2) improvement rate ≥10%) was correlated with serum MMP-9 expression, baseline Sa(O2) and p(O2). Conclusion: Increase of serum TIMP-1 and MMP-9 expressions in COPD patients was correlated with symptoms and scores of quality of life, and the expressions were also correlated with short-term treatment reactivity. (author)
[en] Tetracentron sinense is an endangered tree in China in appendix III of CITES. The current status and dynamics of wild population of T. sinense are unknown, but are vital to its conservation. Diameter at breast height (or basal height for individuals <2.5 m) of all individuals of the T. sinense population in Meigu Dafengding Nature Reserve was investigated. Population size structure, time-specific life tables, survival analysis, and time series analysis were used to analyze the conservation status and dynamics of a natural population. The size structure of the population showed a spindle shape, with few younger individuals (including seedling and sapling) being present, and more middle-aged and aged individuals. The survival curve was a Deevey-type II. The mortality rate, killing power, mortality density, and hazard rate of the population all peaked in the 6th and 12th age-classes. In the first six age-classes, survival rate decreased monotonically, while the cumulative mortality rate rapidly increased, after which the change in trend became relatively gentle. The population size is expected to decrease rapidly in the future 6 and 12 age-classes. The result showed that the natural population was relatively stable, but was in the early stage of decline. The population size of T. sinense in Meigu Dafengding Reserve decreased during the early stage, stabilized in middle stage, and declined in the final stage. The lack of seedlings or saplings might reflect f bottleneck in the regeneration of T. sinense natural population. (author)
[en] In this work, the effect of friction stir processing (FSP) on microstructure and mechanical properties of an Al-5Mg-0.2Sc-0.1Zr alloy was investigated in detail. The results showed that the as-cast alloy exhibited equiaxed grain structure with a large number of primary Al(Sc,Zr) particles inside. FSP imposed a significant grain-refining effect on the alloy, changing the average grain size of 50.5 μm to 2.4 μm, which is attributed to the occurrence of dynamic recrystallization and generation of nanoscaled Al(Sc,Zr) precipitates. These Al(Sc,Zr) dispersoids intense impeded the movement of dislocation and grain boundaries and hindered the growth of recrystallized grains, resulting in a remarkable grain-refining strengthening, substructure strengthening and precipitation strengthening effect. On the other hand, the residual primary Al(Sc,Zr) particles gave rise to a loss in ductility.
[de]Im Rahmen dieser Arbeit wurde der Einfluss einer mittels Rührreib-Bearbeitung (engl. Friction Stir Processing (FSP)) erzeugten Gefügeumwandlung auf die Mikrostruktur und die mechanischen Eigenschaften der Legierung Al-5Mg-0.2Sc-0.1Zr eingehend untersucht. Die Ergebnisse zeigten, dass die Legierung im Gusszustand eine gleichachsige Kornstruktur mit einer großen Zahl an primären Al(Sc,Zr)-Partikeln aufwies, die sich im Korninnern befanden. FSP wirkte sich deutlich kornfeinend auf die Legierung aus und führte zu einer Abnahme der mittleren Korngröße von 50,5 μm auf 2,4 μm, was auf das Auftreten von dynamischer Rekristallisation und der Entstehung von nanoskaligen Al(Sc,Zr)-Ausscheidungen zurückzuführen ist. Diese Al(Sc,Zr)-Dispersoide stellen ein erhebliches Hindernis für die Bewegung von Versetzungen und Korngrenzen und für das Wachstum rekristallisierter Körner dar, was eine Festigkeitssteigerung durch Kornfeinung, Substrukturverfestigung und Ausscheidungshärtung zur Folge hat. Andererseits führten die verbleibenden primären Al(Sc,Zr)-Partikel zu einem Duktilitätsverlust.
[en] We demonstrate highly efficient InGaN-based mini-size green light-emitting diodes (mLEDs) with AlGaN insertion layer in InGaN/GaN multiple quantum wells (MQWs) using metal organic chemical vapor deposition (MOCVD). High resolution transmission electron microscopy (HRTEM) results reveal that ‘V’ defects within active region can be effectively reduced by AlGaN insertion layer. Photoluminescence (PL) and time resolved photoluminescence (TRPL) results indicate an increase of radiative recombination efficiency. Very high performance 523 nm InGaN green flip-chip mLEDs (0.025 mm2) with distributed Bragg reflector (DBR) show a high external quantum efficiency (EQE) of 38.0%, a high wall-plug efficiency (WPE) of 32.1% and a low forward voltage of 2.8 V at a working current density of 20 A cm−2, which are very promising for display application. (paper)
[en] Aeromagnetic surveys using unmanned aerial vehicles (UAV) can be used in low-altitude detailed detection of small-scale magnetic anomalies and offers an auxiliary means for geomagnetic survey on land. However, excessive weight of the detection instruments and strong magnetic interference remain problems. To address them, an aeromagnetic system for a multi-rotor UAV based on the Overhauser sensor was designed. To ensure aeromagnetic surveys have high precision and are omnidirectional and fast, a miniaturized Overhauser sensor and a narrow-band tuned filter were designed and a short-time high-precision measurement method was proposed. Furthermore, the ridge regression is used to reduce the adverse effects of multicollinearity and enhance the stability of the compensation coefficient estimators. Both laboratory and flight tests were conducted. Overall, the results show that the static and dynamic noise is 0.029 nT, 0.041 nT, respectively, and the improvement ratio of aeromagnetic interference is 4.38 in the dynamic tests; a test of iron pipe detection was performed to verify the overall performance of the aeromagnetic system.
[en] Tobacco wildfire disease is common globally, and climate change may increase the risk of outbreaks. Therefore, there is an urgent need to establish an effective climate model to forecast the occurrence of wildfire disease. To design such a model, we collected data for 40 wildfire disease indices via tobacco field surveys and data for 15 climate factors of Guiyang County in China from 2012 to 2016. First, we built multiple linear regression (MLR), stepwise linear regression (SLR) and support vector regression (SVR) models using three climate features (precipitation, mean daily temperature and sunshine duration), and we could not find an effective model. Second, we built three corresponding models using expanded 15 climate features and an in-house WDEM method (the worst descriptor elimination multi-roundly), and the independent test results showed that the best SVR model had not only a higher predictive accuracy ( = 0.94) but also a better stability. Finally, we further evaluated the biological significance of their retained climate features and the single-factor effects of the best model according to the interpretability analysis, and our results indicated that (1) the three climate factors (minimum value of wind velocity, daily range of temperature and daily pressure) strongly affected the occurrence of wildfire disease; (2) the ranges of relative humidity and sunshine hours were negatively correlated with the occurrence of wildfire disease, while daily mean vapour pressure was positively correlated with the occurrence of the disease. Our work enables a useful theoretical prediction for wildfire disease, especially in terms of climate-related predictions.
[en] To provide good performance of spatial and energy measurement for the experiments at the HIRFL-CSR, a double-sided silicon strip detector (DSSD) has been designed as the pixel detector. Performance of the DSSD has been characterized in a vacuum chamber with the alpha source. The reverse leakage current of the DSSD is measured to be ∼3 nA/cm2⋅ 100 μm at the full depleted voltage and the energy resolution of each strip is better than 1%. Besides, the energy information of charge sharing events can be well measured. In this paper, the design, manufacture and performance characterization of the DSSD will be discussed.
[en] Highlights: • FOP share similar radiological features on CT with peripheral LA, which may lead to unnecessary pulmonary segmentectomy or lobectomy. • Up to now, there were no noninvasive and high accuracy methods to discriminate FOP from peripheral LA. • The radiomics can be extracted to reveal the heterogeneity of tumor, which provides a more comprehensive and robust approach to discriminate these two diseases. • We provided evidences that clinicoradiological assessment combined with the radiomics showed higher diagnostic accuracy in discriminating FOP from peripheral LA. Recommended articlesNo articles found.