141 research outputs found
Flutter Influence Mode Analysis of High Speed Wing Model
AbstractIn flutter wind tunnel test, the matching degree between scaled model and prototype would directly affect the reliability of test results. It is difficult to achieve completely dynamic similarity because of some material or technological constrains, and only lower order modes including mode shape and frequency are accurately simulated to construct a compromised model. Theoretical support would be necessary to answer the question which modes must be simulated to guarantee data validity of wind tunnel flutter test. An analytical study of a sweepback winghas been undertaken to estimate the flutter influence mode needed for accurate flutter prediction by analyzing generalized aerodynamic stiffness coefficient, unsteady aerodynamic force and flutter results. The results show that the aerodynamic stiffness coefficient with expression of mode shape could be taken as a quick criterion for mode selection in flutter model design and analysis
Mitogen-activated protein kinase and method of use to enhance biotic and abiotic stress tolerance in plants
The present invention relates to the mitogen-activated protein kinase called MAPK5. The rice MAPK5 gene, its protein and kinase activity were induced by abscisic acid, pathogen infection, wounding, drought, salt and cold temperature. However, suppression of MAPK5 expression and kinase activity in dsRNAi transgenic plants resulted in constitutive expression of pathogenesis-related genes such as PR-1 and PR-10 but enhanced resistance to fungal and bacterial pathogens. In contrast, overexpressed transgenic lines exhibited elevated MAPK5 kinase activity and increased tolerance to drought, salt and cold stresses. This invention also provides methods for increasing tolerance to abiotic and biotic stress in plant using MAPK5
First identification of primary nanoparticles in the aggregation of HMF
5-Hydroxymethylfurfural [HMF] is an important intermediate compound for fine chemicals. It is often obtained via hydrothermal treatment of biomass-derived carbohydrates, such as fructose, glucose and sucrose. This study investigates the formation of carbonaceous spheres from HMF created by dehydration of fructose under hydrothermal conditions. The carbonaceous spheres, ranging between 0.4 and 10 μm in diameter, have granulated morphologies both on the surface and in the interior. The residual solution is found to contain a massive number of primary nanoparticles. The chemical structure of the carbonaceous spheres was characterised by means of FTIR and NMR spectroscopies. Based on these observations, a mechanism involving the formation and aggregation of the nanoparticles is proposed. This mechanism differs considerably from the conventional understanding in the open literature
Comparison of saline infusion test and captopril challenge test in the diagnosis of Chinese with primary aldosteronism in different age groups
BackgroundTo explore the diagnostic accuracy and the optimal cutoff value between the saline infusion test (SIT) and captopril challenge test (CCT) [including the value and suppression of plasma aldosterone concentration (PAC)] for primary aldosteronism (PA) diagnosing.MethodsA total of 318 patients with hypertension were consecutively enrolled, including 126 patients with PA and 192 patients with essential hypertension (EH), in this observational study. The characteristics of patients and laboratory examinations were collected and compared. The comparison between SIT and CCT was carried by drawing the receiver operator characteristic curve (ROC) and calculating the area under the curve (AUC) to explore the diagnostic accuracy and the optimal cutoff value.ResultsThe average age was 51.59 ± 10.43 in the PA group and 45.72 ± 12.44 in the EH group (p<0.05). The optimal cutoff value was 10.7 ng/dL for post-CCT PAC, 6.8 ng/dL for post-SIT PAC, and 26.9% for suppression of post-CCT PAC. The diagnostic value of post-CCT PAC was the highest with 0.831 for the AUC and 0.552 for the Youden index. The optimal cutoff value for patients who were <50 years old was 11.5 ng/dL for post-CCT PAC and 8.4 ng/dL for post-SIT PAC. The suppression of post-CCT PAC turned to 18.2% for those of age 50 or older.ConclusionCompared with SIT, CCT had a higher diagnostic value when post-CCT PAC was used as the diagnostic criterion in Chinese people, while the selection of diagnostic thresholds depended on patient age
Major vault protein suppresses obesity and atherosclerosis through inhibiting IKK-NF-kappa B signaling mediated inflammation
Macrophage-orchestrated, low-grade chronic inflammation plays a pivotal role in obesity and
atherogenesis. However, the underlying regulatory mechanisms remain incompletely
understood. Here, we identify major vault protein (MVP), the main component of unique
cellular ribonucleoprotein particles, as a suppressor for NF-κB signaling in macrophages. Both
global and myeloid-specific MVP gene knockout aggravates high-fat diet induced obesity,
insulin resistance, hepatic steatosis and atherosclerosis in mice. The exacerbated metabolic
disorders caused by MVP deficiency are accompanied with increased macrophage infiltration
and heightened inflammatory responses in the microenvironments. In vitro studies reveal that
MVP interacts with TRAF6 preventing its recruitment to IRAK1 and subsequent oligomerization and ubiquitination. Overexpression of MVP and its α-helical domain inhibits the
activity of TRAF6 and suppresses macrophage inflammation. Our results demonstrate that
macrophage MVP constitutes a key constraint of NF-κB signaling thereby suppressing
metabolic diseases
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