Search

Sugarcane straw returned to the field has rapidly increased due to the bane on straw burning in China. Straw returning of new sugarcane cultivars has been practiced in the fields. Still, its response has not been explored on soil functionality, microbial community and yield of different sugarcane cultivars. Therefore, a comparison was made between an old sugarcane cultivar ROC22 and a new sugarcane cultivar Zhongzhe9 (Z9). The experimental treatments were: without (R, Z), with straw of the same cultivar (RR, ZZ), and with straw of different cultivars (RZ, ZR). Straw returning improved the contents of soil total nitrogen (TN by 73.21%), nitrate nitrogen (NO3—N by 119.61%), soil organic carbon (SOC by 20.16%), and available potassium (AK by 90.65%) at the jointing stage and were not significant at the seedling stage. The contents of NO3—N was 31.94 and 29.58%, available phosphorus (AP 53.21 and 27.19%), and available potassium (AK 42.43 and 11.92%) in RR and ZZ were more than in RZ and ZR. Straw returning with the same cultivar (RR, ZZ) significantly increased the richness and diversity of the rhizosphere microbial community. The microbial diversity of cultivar Z9 (treatment Z) was greater than that of cultivar ROC22 (Treatment R). In the rhizosphere, the relative abundance of beneficial microorganisms Gemmatimonadaceae, Trechispora, Streptomyces, Chaetomium, etc., increased after the straw returned. Sugarcane straw enhanced the activity of Pseudomonas and Aspergillus and thus increased the yield of sugarcane., The richness and diversity of the rhizosphere microbial community of Z9 increased at maturity. In ROC22, bacterial diversity increased, and fungal diversity decreased. These findings collectively suggested that the impact of Z9 straw returning was more beneficial than ROC22 on the activity of rhizosphere microorganism’s soil functionality and sugarcane production.

Erianin is a natural product derived from the traditional Chinese herb, Dendrobium chrysotoxum, which is highly valued for its antitumor activity in various cancer cells. However, the specific mechanism of antitumor activity of erianin in human hepatocellular carcinoma remains unclear. This study aimed to investigate erianin-induced apoptosis in human hepatocellular carcinoma HepG2 cells. The proliferation of HepG2 cells was significantly inhibited by the treatment of erianin in a doseand time-dependent manner. In addition, erianin induced a series of apoptosis-related events in HepG2 cells, including G2/M cell cycle arrest, the loss of the mitochondrial membrane potential, elevation of intracellular Ca2+, and accumulation of reactive oxygen species. Erianin activated the caspase-3 and caspase-9 without a change in caspase-8, accompanied by upregulation of the expression of Bax and downregulation of the expression of Bcl-2 along with cytochrome C release from the mitochondria. There was no significant change in Fas and FasL expression, indicating that the exogenous pathway is not involved in erianin-induced apoptosis. In summary, it concluded that erianin-induced apoptosis in HepG2 cells is through a mitochondria-mediated pathway. The results of this study suggest that erianin may serve as a novel therapeutic agent for the treatment of human hepatocellular carcinoma in the future.

To better understand the role of China in the financial integration, this study attempts to empirically investigate the interactions between China and other major global economies in international stock markets. It consists of three papers to examine the impact of turbulent events, bilateral trade, and policy uncertainty on China’s interaction with major global stock markets. The first paper investigates the impact of the US-China Trade War on co-movements between US and Chinese stock markets. The results indicate that co-movements amongst mainland China, Hong Kong and US stock markets are positively affected by news releases and, after the official start of the trade war (6th July 2018), are enhanced significantly. More precisely, there is also empirical evidence of positive announcement effects in stock market co-movements between the US and mainland China in specific sectors (particularly, Industrials and Information Technology). For international investors, this evidence suggests that the US-China Trade War has reduced the benefit of portfolio diversification in managing risk. The second paper investigates stock market co-movement between China and its 12 trading partners in the Asia-Pacific region after the Global Financial Crisis (GFC). The empirical results show that recent events (specifically, the Shanghai stock market crash, the US-China tariff war, and the COVID-19 pandemic) have increased the incidences of contagion across stock markets in China and its trading partners. Moreover, bilateral trade and market similarities are major drivers of stock market co-movements between China and developed partners, as well as between China and emerging partners. Apart from country-pair-specific factors, common factors (such as the Chinese illiquidity pressure) also affect the co-movements between Chinese and its partners' stock markets during the full period of the study, as well as during the periods of turmoil. The regression results for contagion episodes are mixed. The third paper attempts to compare the impact of Chinese and US economic policy uncertainty (proxied by the EPU index) on the volatility of eleven major stock markets. Both daily and monthly data are utilized in this empirical research. The empirical results show that the impact of US EPU is reinforced at daily and monthly frequencies during the GFC, with European stock markets affected to a greater extent by the GFC. The rising influence of Chinese EPU after the GFC is observed at monthly frequency in several stock markets located in Asia and elsewhere. The dynamic pattern of spillovers from EPU indices to stock volatility suggests the dominant role of US EPU in most markets at daily frequency, and that the extent of spillovers is driven by turbulent events such as the financial crisis and the COVID-19 pandemic.

The microwave-assisted catalytic pyrolysis (MACP) of cellulose was carried out using modified HZSM-5 catalysts for bio-oil production. The catalysts of Fe/HZSM-5, Ni/HZSM-5 and Fe–Ni/HZSM-5 were developed and characterized by the X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The bio-oil was characterized by the Fourier transform infrared analyzer (FTIR) and gas chromatography/mass spectrometry (GC/MS). Results showed that Fe/HZSM-5 enhanced the yields of bio-oil by 11.4% and decreased the coke by about 24% compared to HZSM-5 without modification. The saccharides in bio-oil disappeared and were totally converted into phenols and low molecular compounds with the catalysis of Fe–Ni/HZSM-5. Fe–Ni/HZSM-5 showed high selectivity of phenols (20.86%) in the bio-oil. It was a unique finding because usually phenols can only be obtained by the pyrolysis of lignin, not cellulose. The formation of phenols from MACP of cellulose was probably caused by the conversion of furans to aromatics in the pores of HZSM-5, and followed by further conversion of aromatics into phenols on the external surface of HZSM-5.

Sialic acid-binding immunoglobulin-like lectins, also known as Siglecs, have recently been designated as glyco-immune checkpoints. Through their interactions with sialylated glycan epitopes overexpressed on tumor cells, inhibitory Siglecs on innate and adaptive immune cells modulate signaling cascades to restrain anti-tumor immune responses. However, the mechanisms underlying these processes are just starting to be elucidated. We discover that when human natural killer (NK) cells attack tumor cells, glycan remodeling occurs on the target cells at the immunological synapse. This remodeling occurs through both transfer of sialylated glycans from NK cells to target tumor cells and accelerated de novo synthesis of sialosides on the tumor cell themselves. The functionalization of NK cells with a high-affinity ligand of Siglec-7 leads to multifaceted consequences in modulating Siglec-7-regulated NK-activation. At high levels, the added Siglec-7 ligand suppresses NK-cytotoxicity through the recruitment of Siglec-7, whereas at low levels the same ligand triggers the release of Siglec-7 from the cell surface into the culture medium, preventing Siglec-7-mediated inhibition of NK cytotoxicity. These results suggest that glycan engineering of NK cells may provide a means to boost NK effector functions.

The impact of global environmental changes on the diversity and functioning of terrestrial ecosystems has received increasing attention. Many studies evaluated the effects of single -and less often multiple- global change factors on soil N cycling processes in grasslands. However, these studies have not recognized that altered precipitation regime also has an influence on wet N deposition regime. Further, the response of grassland soil N cycling to co-occurring multiple global change factors and disturbance like fire, and how N cycling response to fire could differ under different global change scenarios, remains unclear. This strongly restricts our ability to understand and predict global change effect on grasslands. In this work, two experiments were conducted: (i) a mesocosm experiment to assess the combined effects of increased N deposition and changes in both the amount and frequency of rainfall on soil N cycling in a semi-arid Monsoon grassland; and (ii) an in situ experiment to assess the combined effects of elevated CO2, warming, increased precipitation, N deposition and fire on soil N cycling in a Mediterranean grassland. This allows studying the -possibly interactive- effects of several global change factors on the abundances of soil N-cycling microbial communities. The microbial groups studied were ammonia oxidizing bacteria and archaea (AOB and AOA, respectively), nirK- and nirS-nitrite reducers, nosZI- and nosZII-N2O reducers, plus Nitrobacter and Nitrospira for the Mediterranean grassland. The main results and conclusions are: 1）The responses of different groups of soil (de)nitrifiers to global change scenarios differed strongly regardless the grassland type. AOB were mostly driven by N. In contrast, AOA were more sensitive to soil water dynamics than N dynamics in both grasslands. Nitrobacter abundance was mostly affected by global change factors through their effects on AOB abundance, whereas Nitrospira abundance was more related to changes of AOA in the Mediterranean grassland. Similarly, nirK- and nirS-harboring nitrite reducers and nosZI-harboring N2O reducers were more sensitive to N deposition than nosZII-harboring N2O reducers, and nirK- and nirS-bacteria positively responded to reduced precipitation. This highlights niche differentiation between them and indicates that the balance between them may be altered in the future; 2）In the Mediterranean grassland, where high N deposition was simulated by two N addition events each year, the N effect dominated global change effects. In contrast, in the Monsson grassland, chronic wet N deposition did not increase denitrifier abundance and only weakly increased soil N2O emissions. This was explained by the efficient capture of added N by the dominant grass species and by the increased plant growth leading to increased transpiration and decreased soil moisture. 3）For both grasslands, the interaction between global change factors on soil N cycling could not be predicted simply by studying the effects of one or two factors. These interactive effects were explained by effects on key environmental variables like soil moisture, mineral N availability, pH and belowground plant growth.These results demonstrates the limitation of predicting how (de)nitrifiers respond to global change scenarios involving multiple factors only from studying single factor effects. Particularly, interactive effects were observed between N deposition, decreased precipitation amount and altered precipitation frequency in the Monsoon grassland; and between fire, N deposition, warming, elevated precipitation and elevated CO2 in the Mediterranean grassland. This calls for more comprehensive studies in the global change biology domain. Modelling and evaluating the generality of these complex interaction effects is thus a high priority for research to predict the responses of soil N cycling processes to global change and feedbacks on climate in the future; L’impact de l’homme sur l’environnement mondial et sur la diversité et le fonctionnement des écosystèmes terrestres fait l’objet d’une attention croissante. De nombreuses études ont évalué les effets de facteurs du changement global tels sur les processus de cycle de l'azote du sol dans les prairies. Cependant, ces études n'ont pas pris en compte le fait que la modification du régime de précipitations avait également une influence sur le régime de dépôt d'azote. En outre, la réponse du cycle de l'azote dans les sols des prairies à de multiples facteurs du changement global agissant ensemble et parfois en même temps que des perturbations telles que les incendies, doit encore être étudiée. Cela limite fortement notre capacité à comprendre et à prévoir les effets du changement global sur les prairies. Dans ce travail de doctorat, deux expériences ont été menées: (i) une expérience en mésocosme pour évaluer les effets combinés d'une augmentation des dépôts d'azote et de changements dans la quantité et la fréquence des précipitations sur le cycle de l'azote édaphique dans une prairie semi-aride; (ii) une expérience in situ pour évaluer les effets combinés de l'augmentation de la concentration en CO2, du réchauffement, d’une modification des précipitations, du dépôt d'azote et d’un feu sur le cycle de l'azote du sol dans une prairie méditerranéenne. Cela permet d'étudier les effets de la combinaison de plusieurs facteurs de changement global (et d’une perturbation feu) sur l'abondance des communautés microbiennes du cycle de l'azote.Les groupes microbiens étudiés étaient les bactéries et les archées oxydant l'ammoniac (AOB et AOA, respectivement), les réducteurs de nitrite porteuses des gènes nirK ou nirS, et les réducteurs de N2O porteurs des gènes nosZI- et nosZII, plus les bactéries oxydant le nitrite du genre Nitrobacter et Nitrospira pour la prairie méditerranéenne. Les principaux résultats et conclusions sont les suivants: 1) Les réactions des différents groupes de (dé)nitrifiants aux scénarios de changement global différaient fortement quel que soit le type de prairie. Les AOB étaient principalement dépendant de la disponibilité en azote En revanche, dans les deux prairies, les AOA étaient plus sensibles à la dynamique de l'eau du sol que la dynamique de l'azote. L'abondance des Nitrobacter étaient principalement affectée par les facteurs de changement global affectant l'abondance de l'AOB, tandis que l'abondance des Nitrospira était davantage liée aux changements d'abondance des AOA dans la prairie méditerranéenne. 2）Dans la prairie californienne où deux dépôts d'azote élevés avaient lieu chaque année, l'effet de l'azote dominait les effets du changement global. En revanche, dans la prairie chinoise, les dépôts d’azote simulés par des apports chroniques couplés aux événements de précipitation n’augmentaient pas l’abondance des dénitrifiants et ne faisaient que légèrement augmenter les émissions de N2O. 3） Pour les deux prairies, l'interaction entre les facteurs du changement global sur le cycle de l'azote du sol ne pouvait pas être prédite simplement en étudiant les effets d'un ou de deux facteurs. Ces effets interactifs ont pu être expliqués par des effets sur des variables environnementales clés telles que l'humidité du sol, la disponibilité de l'azote minéral, le pH et la croissance des racines. Ces résultats démontrent qu'il est impossible de prédire comment les (dé)nitrifiants et la (dé)nitrification répondent aux scénarios de changement global impliquant de multiples facteurs uniquement à partir de la connaissance d'effets de facteurs étudiés isolément. Cela nécessite donc des études plus approfondies dans le domaine de la biologie des changements globaux. La modélisation et l'évaluation de la généralité de ces effets d'interaction complexes constituent donc une priorité majeure pour les chercheurs qui veulent prédir les réponses du cycle de l'azote dans le sol au changement global et les rétroactions sur le climat.

In order to solve the problem that the community partition results are not reusable in the information sensitive opportunity network, a hierarchical model of opportunity network is proposed. First, the physical node set of the opportunity network is mapped to the virtual node set corresponding to the message type, and the virtual opportunity network layer is established on this basis. Then, at the virtual opportunity network layer, social relations are established for the virtual node set. Finally, the social relations of virtual node sets are processed for community division. The experiment shows that the opportunity network hierarchical model under the unsteady topology condition is very effective.

The impact of global environmental changes on the diversity and functioning of terrestrial ecosystems has received increasing attention. Many studies evaluated the effects of single -and less often multiple- global change factors on soil N cycling processes in grasslands. However, these studies have not recognized that altered precipitation regime also has an influence on wet N deposition regime. Further, the response of grassland soil N cycling to co-occurring multiple global change factors and disturbance like fire, and how N cycling response to fire could differ under different global change scenarios, remains unclear. This strongly restricts our ability to understand and predict global change effect on grasslands. In this work, two experiments were conducted: (i) a mesocosm experiment to assess the combined effects of increased N deposition and changes in both the amount and frequency of rainfall on soil N cycling in a semi-arid Monsoon grassland; and (ii) an in situ experiment to assess the combined effects of elevated CO2, warming, increased precipitation, N deposition and fire on soil N cycling in a Mediterranean grassland. This allows studying the -possibly interactive- effects of several global change factors on the abundances of soil N-cycling microbial communities. The microbial groups studied were ammonia oxidizing bacteria and archaea (AOB and AOA, respectively), nirK- and nirS-nitrite reducers, nosZI- and nosZII-N2O reducers, plus Nitrobacter and Nitrospira for the Mediterranean grassland. The main results and conclusions are: 1）The responses of different groups of soil (de)nitrifiers to global change scenarios differed strongly regardless the grassland type. AOB were mostly driven by N. In contrast, AOA were more sensitive to soil water dynamics than N dynamics in both grasslands. Nitrobacter abundance was mostly affected by global change factors through their effects on AOB abundance, whereas Nitrospira abundance was more related to changes of AOA in the Mediterranean grassland. Similarly, nirK- and nirS-harboring nitrite reducers and nosZI-harboring N2O reducers were more sensitive to N deposition than nosZII-harboring N2O reducers, and nirK- and nirS-bacteria positively responded to reduced precipitation. This highlights niche differentiation between them and indicates that the balance between them may be altered in the future; 2）In the Mediterranean grassland, where high N deposition was simulated by two N addition events each year, the N effect dominated global change effects. In contrast, in the Monsson grassland, chronic wet N deposition did not increase denitrifier abundance and only weakly increased soil N2O emissions. This was explained by the efficient capture of added N by the dominant grass species and by the increased plant growth leading to increased transpiration and decreased soil moisture. 3）For both grasslands, the interaction between global change factors on soil N cycling could not be predicted simply by studying the effects of one or two factors. These interactive effects were explained by effects on key environmental variables like soil moisture, mineral N availability, pH and belowground plant growth.These results demonstrates the limitation of predicting how (de)nitrifiers respond to global change scenarios involving multiple factors only from studying single factor effects. Particularly, interactive effects were observed between N deposition, decreased precipitation amount and altered precipitation frequency in the Monsoon grassland; and between fire, N deposition, warming, elevated precipitation and elevated CO2 in the Mediterranean grassland. This calls for more comprehensive studies in the global change biology domain. Modelling and evaluating the generality of these complex interaction effects is thus a high priority for research to predict the responses of soil N cycling processes to global change and feedbacks on climate in the future, L’impact de l’homme sur l’environnement mondial et sur la diversité et le fonctionnement des écosystèmes terrestres fait l’objet d’une attention croissante. De nombreuses études ont évalué les effets de facteurs du changement global tels sur les processus de cycle de l'azote du sol dans les prairies. Cependant, ces études n'ont pas pris en compte le fait que la modification du régime de précipitations avait également une influence sur le régime de dépôt d'azote. En outre, la réponse du cycle de l'azote dans les sols des prairies à de multiples facteurs du changement global agissant ensemble et parfois en même temps que des perturbations telles que les incendies, doit encore être étudiée. Cela limite fortement notre capacité à comprendre et à prévoir les effets du changement global sur les prairies. Dans ce travail de doctorat, deux expériences ont été menées: (i) une expérience en mésocosme pour évaluer les effets combinés d'une augmentation des dépôts d'azote et de changements dans la quantité et la fréquence des précipitations sur le cycle de l'azote édaphique dans une prairie semi-aride; (ii) une expérience in situ pour évaluer les effets combinés de l'augmentation de la concentration en CO2, du réchauffement, d’une modification des précipitations, du dépôt d'azote et d’un feu sur le cycle de l'azote du sol dans une prairie méditerranéenne. Cela permet d'étudier les effets de la combinaison de plusieurs facteurs de changement global (et d’une perturbation feu) sur l'abondance des communautés microbiennes du cycle de l'azote.Les groupes microbiens étudiés étaient les bactéries et les archées oxydant l'ammoniac (AOB et AOA, respectivement), les réducteurs de nitrite porteuses des gènes nirK ou nirS, et les réducteurs de N2O porteurs des gènes nosZI- et nosZII, plus les bactéries oxydant le nitrite du genre Nitrobacter et Nitrospira pour la prairie méditerranéenne. Les principaux résultats et conclusions sont les suivants: 1) Les réactions des différents groupes de (dé)nitrifiants aux scénarios de changement global différaient fortement quel que soit le type de prairie. Les AOB étaient principalement dépendant de la disponibilité en azote En revanche, dans les deux prairies, les AOA étaient plus sensibles à la dynamique de l'eau du sol que la dynamique de l'azote. L'abondance des Nitrobacter étaient principalement affectée par les facteurs de changement global affectant l'abondance de l'AOB, tandis que l'abondance des Nitrospira était davantage liée aux changements d'abondance des AOA dans la prairie méditerranéenne. 2）Dans la prairie californienne où deux dépôts d'azote élevés avaient lieu chaque année, l'effet de l'azote dominait les effets du changement global. En revanche, dans la prairie chinoise, les dépôts d’azote simulés par des apports chroniques couplés aux événements de précipitation n’augmentaient pas l’abondance des dénitrifiants et ne faisaient que légèrement augmenter les émissions de N2O. 3） Pour les deux prairies, l'interaction entre les facteurs du changement global sur le cycle de l'azote du sol ne pouvait pas être prédite simplement en étudiant les effets d'un ou de deux facteurs. Ces effets interactifs ont pu être expliqués par des effets sur des variables environnementales clés telles que l'humidité du sol, la disponibilité de l'azote minéral, le pH et la croissance des racines. Ces résultats démontrent qu'il est impossible de prédire comment les (dé)nitrifiants et la (dé)nitrification répondent aux scénarios de changement global impliquant de multiples facteurs uniquement à partir de la connaissance d'effets de facteurs étudiés isolément. Cela nécessite donc des études plus approfondies dans le domaine de la biologie des changements globaux. La modélisation et l'évaluation de la généralité de ces effets d'interaction complexes constituent donc une priorité majeure pour les chercheurs qui veulent prédir les réponses du cycle de l'azote dans le sol au changement global et les rétroactions sur le climat.

Usually, force tests and pressure tests are conducted with different model in wind tunnel which could cause trouble for aircraft design as the pressure test results always could not match the force test results. So attempts to do force tests along with pressure tests are conducted. Results show that it is possible to do force test based on pressure-test-model when some improvements are done with the model and sting. Both force and pressure test results can be measured at the same time. The amount of pressure test results need not be reduced, and yet precision and accuracy of the force tests are acceptable for aircraft design, and this technology can be popularized with low cost.

In order to improve quality and efficiency of Blended Wing-Body (BWB) aircraft’s high-speed wind tunnel test, while verify the reliability and practicability of flange balance in the test of such a layout aircraft. The specific flange-connected balance of BWB aircraft was designed and processed, which was designed under the limits of aerodynamic load and model interspace size. The comparison test results between the flange balance and the traditional cone balance were obtained by conducting a comparison test in the 2.4-meters transonic wind tunnel. The results show that the flange balance has high measurement accuracy and good correlation with the traditional cone balance. Flange balance meets the requirement of BWB layout aircraft high speed wind tunnel test and has a broad application prospect, so that it could be popularized in the future.

Previous studies have yielded controversial results related to the contribution of matrix metalloproteinase-2 (MMP-2) -1306 C/T and -735 C/T polymorphisms in the progression of coronary artery disease (CAD). This study aimed to provide strong evidence for the role of the 2 polymorphisms in genetic risk of CAD. The human case-control studies regarding the association of MMP-2 polymorphisms with CAD risk were systematically identified through online databases (PubMed, Embase, the Cochrane Library, and CNKI) and manual search. Inclusion criteria were defined for the eligible studies. The fixed-effects meta-analysis was performed to combine the values when homogeneity was indicated. Alternatively, the random-effects meta-analysis was utilized. A total of 2118 samples were analyzed in the meta-analysis of -1306 C/T. The odds ratio for the initially tested genetic model was 0.93 (95% confidence interval: 0.78–1.10 under TT + CT vs CC). The remaining comparisons similarly showed -1306 C/T genotypes were not significantly associated with the risk of CAD. We noted the same trend when data were retrained to myocardial infarction studies. Meta-analysis of -735 C/T suggested no clear association with the development of CAD. The results of the current work fail to support a significant involvement of MMP-2 -1306 C/T and -735 C/T polymorphisms in the risk of developing CAD.

Camera calibration is a very important and necessary step in computer vision, especially in 3D reconstruction, target tracking and positioning. In this paper, a GPS coordinate is first introduced and incorporated into Tsai two-step camera calibration method. Owing to the limitation of the accuracy of GPS receivers at present, there's a relatively large error in camera calibration parameters. A hybrid optimization algorithm (GA-PSO) by combining a genetic algorithm and particle swarm optimization is proposed further to improve camera parameters. Experimental results prove that our method is feasible and efficient.

Single-phase active power factor correction (PFC) circuit is a double closed loop control system. Based on the analysis of PFC working mechanism, the dynamic model of the system is built. The closed-loop structure figure as well as transfer function of each part are present. Also, the function and the designing method of current loop and voltage loop are explained in this paper.

The development of China's animation should take some excellent artistic forms of our nation into consideration, only those animation works with national characteristics are precious. The designer should comprehend the essence of traditional cultures, combine the traditional artistic elements on modeling and can recreate. This paper creates animation images with Chinese culture characteristics through analyzing the Chu art characteristics and taking them as artistic reference of animation modeling. Its application in the FLASH software and some noticeable problems are considered; and the animation modeling has unique artistic charms and values.