Study on coupled mode flutter parameters of large wind turbine blades.

As the size of wind turbine blades increases, the flexibility of the blades increases. In actual operation, airflow flow can cause aerodynamic elastic instability of the blade structure. Long blades may experience coupled mode flutter due to the bending torsion coupling effect, leading to blade failure. Based on Euler Bernoulli beam theory combined with Theodorsen non directional aerodynamic loads, a blade flutter characteristic equation is established through finite element method. Taking NREL 5 MW wind turbine blades as an example, analyze the influence of parameter changes in different regions of the blades on flutter characteristics. Research has found that paramter changes in the tip region of blade have the greatest impact on flutter characteristics. The vibration frequency shows an overall upward trend with the increase of waving stiffness and torsional stiffness. The flutter velocity of the three regions tends to stabilize as the bending stiffness decreases. The blade flutter speed increases with the increase of torsional stiffness. The radius of gyration is inversely proportional to the flutter frequency and flutter velocity. The impact of centroid offset on blade structure flutter frequency is minimal, but the centroid offset in the tip region has a greater impact on flutter velocity. Increasing the torsional frequency can prevent coupled mode flutter and provide a theoretical basis for blade flutter prevention design.

Fluorescent-Dye-Labeled Amino Acids for Real-Time Imaging in Arabidopsis thaliana.

Amino acid is the main transport form of reduced nitrogen in plants. To investigate the uptake and source-sink translocation process of plants to help understand their physiological roles and transport mechanisms, we designed and synthesized three fluorescent-dye-labeled amino acids as tools to visualize amino acid transportation in Arabidopsis thaliana; these amino acids consist of amino acids linked to the fluorophore nitrobenzoxadiazole (NBD) with excellent optical properties. Furthermore, we incubated Arabidopsis thaliana with these NBD fluorescent-dye-labeled amino acids for real-time imaging along with fluorescence enhancement for 24 h. The results showed that Arabidopsis thaliana could absorb them directly from the roots to the leaves. Therefore, our fluorescent-dye-labeled amino acids provide a de novo tool and strategy for visualizing amino acid absorption and transportation in plants.

Performance Enhancement of the Poplar Wood Composites Biomimetic Mineralized by CaCO3.

Inspired by the natural matrix-mediated biomineralization, wood composites were prepared by vacuum impregnation using the gel effect of sodium alginate (SA) on calcium ions, which improved the mechanical properties, flame retardant, and smoke suppression properties of the wood composites. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed that the SA inducer had promoted the orderly deposition and directional crystallization of calcium carbonate (CaCO3) inside the wood cell walls and intercellular spaces. The density and weight gain rate of the biomimetic mineralized wood showed that CaCO3 effectively adhered to the interior of wood with SA as an inducer. The compressive and flexural strengths were 15.65% and 37.66% higher than those of the control, respectively. Thermogravimetric analysis (TG) proved that SA alleviated the thermal decomposition and complete combustion of the mineralized wood and improved the thermal stability. Microcalorimetry (MCC) and cone calorimetry (CONE) analyses revealed that the maximum heat release rate (HRR), total heat release (THR), and the total smoke production (TSP) rate of the mineralized wood was reduced by 59.51%, 48.52%, and 51.67%, respectively, compared with those of the control. This research demonstrates the in situ synthesis of CaCO3 within the cellular microstructure of the poplar which is using it as a biotemplate. With the enhancement of the flame retardant property and others, the wood composite biomimetic mineralized materials modified by CaCO3 and SA could be utilized more widely in the construction industry or other fields.

Realizing Improved Sodium-Ion Storage by Introducing Carbonyl Groups and Closed Micropores into a Biomass-Derived Hard Carbon Anode.

Micropores and defects, like oxygen-containing groups, as active sites for sodium-ion storage in hard carbon have attracted considerable attention; nevertheless, most oxygen doping or oxidizing processes inevitably introduce undesired oxygen groups into a carbon framework, leading to deteriorated initial Coulombic efficiency (ICE). Here, precise carbonyl groups and closed micropores are together introduced into biomass-derived hard carbon to enhance the Na-ion storage performance. The hard carbon delivers a large reversible capacity of 354.6 mA h g-1 at 30 mA g-1, a high ICE (88.7%), as well as ultra-long cycling stability (277 mA h g-1 at 0.3 A g-1 over 1000 cycles; 243 mA h g-1 at 1 A g-1 over 5000 cycles). The rate capability and cycling stability of hard carbon in carbonate- and diglyme-based electrolytes are contrasted to demonstrate the superiority of diglyme. Cyclic voltammetry at varied scans and galvanostatic intermittent titration techniques are carried out to clarify the disparity between the two different electrolyte systems. Furthermore, the as-prepared hard carbon is utilized as the anode for sodium-ion full cells exhibiting an energy density of 166.2 W h kg-1 at 0.2 C and a long-cycle life (47.9% retention over 200 cycles at 1 C).

Improvement of vincamine production of endophytic fungus through inactivated protoplast fusion.

Improvement of the production of vincamine in endophytic fungus VINI-7 was performed by using the inactivated protoplast fusion method. The preparation conditions of protoplasts were optimized by systematic trials with various parameters, and inactivated protoplast fusion was subsequently performed. The mycelium in logarithmic growth phase was treated with 1500 U/mL lywallzyme, 1500 U/mL lysozyme, 2000 U/mL cellulase, and 1000 U/mL snailase solution for 3 h at 30 °C and had the best conditions, in which the concentration of the protoplast was 3.17 × 107 cells/mL. Protoplasts were inactivated by heat, ultraviolet, microwave, sodium nitrite, and diethyl sulfate, respectively. Subsequently, protoplasts inactivated by different methods were subjected to respective protoplast fusion. The results showed that the yield of vincamine in fusants inactivated by mutagens was generally higher than that of fusants inactivated by heat. The highest yield of vincamine in two fusants (U-U1 and N-N1) was 31.6 and 38.7 mg, which increased to 162.24 and 221.16%, respectively, as compared to the parent strain (12.05 mg). LC-MS/MS analysis showed that U-U1 and N-N1 fusants could produce vincamine. Furthermore, the results of genetic stability experiments indicated that U-U1 and N-N1 were genetically stable.

Preparation, characterization and evaluation of cellulose nanocrystal/poly(lactic acid) in situ nanocomposite scaffolds for tissue engineering.

Cellulose nanocrystal (CNC)/poly(lactic acid) (PLA) in situ nanocomposite scaffolds were fabricated by in situ polymerization of lactic acid and CNC which was directly utilized as aqueous suspension, followed by a process of thermally induced phase separation. The CNC/PLA in situ nanocomposite porous scaffolds were characterized by mechanical test, protein adsorption, hemolysis test, in vitro degradation measurement, TEM, FTIR, SEM and WAXD. Compared to the PLA scaffold, the CNC/PLA in situ nanocomposite scaffolds showed a greatly increased compression modulus, an improved hemocompatibility and protein adsorption capacity. The inclusion of CNCs boosted the in vitro degradation of the in situ nanocomposite porous scaffolds and facilitated the deposition of Ca2+, CO32-, PO43- ions in simulated body fluid. Furthermore, cell cultures were carried out on the CNC/PLA in situ nanocomposite porous scaffolds. In comparison with the PLA scaffold, the in situ nanocomposite scaffolds improved cell attachment and enhanced cell proliferation, denoting low cytotoxicity and good cytocompatibility. It can therefore be concluded that such scaffolds with excellent mechanical property, biocompatibility, biomineralization capacity and bioactivity hold great potential for bone tissue engineering.

Monogamy relation of multi-qubit systems for squared Tsallis-q entanglement.

Tsallis-q entanglement is a bipartite entanglement measure which is the generalization of entanglement of formation for q tending to 1. We first expand the range of q for the analytic formula of Tsallis-q entanglement. For , we prove the monogamy relation in terms of the squared Tsallis-q entanglement for an arbitrary multi-qubit systems. It is shown that the multipartite entanglement indicator based on squared Tsallis-q entanglement still works well even when the indicator based on the squared concurrence loses its efficacy. We also show that the µ-th power of Tsallis-q entanglement satisfies the monogamy or polygamy inequalities for any three-qubit state.

Apoptosis is induced in the haemolymph and fat body of Spodoptera exigua larvae upon oral inoculation with Spodoptera litura nucleopolyhedrovirus.

Spodoptera exigua multinucleopolyhedrovirus (SeMNPV) and Spodoptera litura nucleopolyhedrovirus (SpltNPV) are genetically similar, but the larvae of S. exigua are not susceptible to SpltNPV. The aim of this study was to identify whether any process was inhibiting SpltNPV infection at some point. S. exigua larvae infected with a high concentration of wild-type SpltNPV by oral inoculation produced a fatal infection in second- or third-instar S. exigua, but the dead larvae did not undergo liquefaction; in contrast, fourth-instar infected larvae remained healthy. RT-PCR analysis of total RNA from infected second-instar larvae targeting immediate-early (ie-0), early (dnapol), late (chit) and very late (polh) genes suggested that SpltNPV initiated infection in the non-susceptible hosts. Total DNA extracted from the haemocytes of infected larvae showed DNA ladders characteristic of apoptosis. Sections of tissue from infected third-instar larvae of S. exigua at 96 h post-inoculation, stained with haematoxylin and eosin, revealed a highly disrupted morphology in the fat body. Apoptosis in fat body tissue was detected using terminal deoxynucleotidyltransferase-mediated fluorescein-dUTP nick end labelling (TUNEL) assays. In situ hybridization revealed the presence of viral DNA within the TUNEL-positive area, indicating viral infection in this tissue. These results suggest that apoptosis limits viral propagation by reducing the number of SpltNPV-infected haemocytes and fat body cells and inhibits disseminated viral infection.

Anatomical and histological observation on the pancreas in adult zebrafish.

OBJECTIVES: To investigate the anatomic structure of the pancreas and the distribution of the islets in adult zebrafish. METHODS: In situ immunofluorescent staining, electron microscopy, and serial paraffin-embedded sectioning with hematoxylin/eosin staining were applied. RESULTS: The pancreas along the intestine included 4 relatively independent and concentrated lobes, in which 4 kinds of islets-principal islets, Brockmann bodies, diffusely existing islets, and single beta-cell-were observed. Some islets contained both alpha and beta cells, whereas some contained only beta cells. The islet number in each adult zebrafish averaged 84.53 +/- 43.77; and the lower quartile, median, and upper quartile were 55.25, 70.50, and 112.00, respectively (n = 40). The different islets were differently distributed in the 4 pancreatic lobes with statistical significance (P < 0.05). Meanwhile, 3 kinds of secretory granules were found in the cytoplasm of different islet cells. CONCLUSIONS: According to the distinct distribution, concentration of the pancreas, and different contents of the islets within the pancreas, 4 lobes of the pancreas along the intestine-the gallbladder-spleen lobe, the middle lobe, the left lobe, and the ventral lobe-were identified in adult zebrafish.

siRNA specific to Pdx-1 disturbed the formation of the islet in early zebrafish embryos.

Pdx-1, an important transcription factor highlighting in the early pancreatic development, islet functions and pancreatic disorders, needs to be more investigated in zebrafish, and siRNA is still seldom applied in zebrafish embryo-related research. Our aim was to explore the role of pdx-1 in pancreatic development of zebrafish embryos by using siRNA approach. Microinjection, reverse transcriptase-PCR (RT-PCR), in situ hybridization and immunofluorescent staining were used in this research, and the morphology of the islet in normal zebrafish embryos, and in those treated with the siRNA specific to pdx-1 (siPDX-1) or siGFP was observed and compared. The expression of pdx-1 was detected in the stages of 1-cell, 2-cell, 4-cell, 8-cell, 16-cell, 16-hour by RT-PCT. The in situ hybridization and immunofluorescent staining results showed that siPDX-1 disturbed the formation of the islet in zebrafish embryos. Pdx-1 played multiple roles in maintaining the phenotype of the islet during embryogenesis in zebrafish.