Scutellarin Ameliorates Renal Injury via Increasing CCN1 Expression and Suppressing NLRP3 Inflammasome Activation in Hyperuricemic Mice

Considerable evidences have indicated that elevated uric acid (UA) was involved in renal tubular injury leading to hyperuricemic nephropathy (HN). Scutellarin is a biologically active flavonoid derived from the Chinese traditional herb Erigeron breviscapus Hand-Mazz, which has been widely used in the treatment of cardiovascular and cerebrovascular diseases. In the present study, we analyzed the effect of scutellarin on HN, by using C57BL/6 mice and human renal tubular epithelial cell line HK-2 which was subjected to adenine/potassium oxonate and UA to mimic a HN injury. The HN mice showed a significant decrease in renal function with the increased SCr and blood urea nitrogen (BUN) (p < 0.05). Hematoxylin-eosin staining results showed a histological injury in HN mice kidney tissues with severe tubular damage. Scutellarin dose dependently alleviated the renal injury of the HN model (p < 0.05), and a dose of 20 mg/kg/day remarkably reduced the Scr level (26.10 +/- 3.23 mu mol/ml vs. 48.39 +/- 7.51 mu mol/ml, p < 0.05) and BUN (151.12 +/- 30.24 mmol/L vs. 210.43 +/- 45.67 mmol/L, p < 0.05) compared with the HN model group. Similarly, scutellarin decreased NGAL, Kim-1, cystatin C, and IL-18 protein expression levels in HN mouse (p < 0.05). Overexpressed CCN1 could not induce NLRP3 inflammasome activation, with no change of mRNA and protein expression levels of NLRP3, ASC, and pro-caspase-1 compared with the control HK-2. However, HK-2 showed a significant NLRP3 inflammasome activation and apoptosis. Importantly, knockdown of CCN1 not only aggravated NLRP3 inflammasome activation and apoptosis but also abrogated the protective effect of scutellarin in UA-induced HK-2 injury. Thus, scutellarin might alleviate HN progression via a mechanism involved in CCN1 regulation on NLRP3 inflammasome activation

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

On short-term fatigue analysis for wind turbine tower of two semi-submersible wind turbines including effect of startup and shutdown processes Research papers

Fatigue limit state design check for offshore wind turbines is based on SN curves and the Palmgren–Miner rule approach and focuses normally on stationary processes for which startup and/or shutdown operations induced transient load processes are normally not accounted for. However, large databases of real-time measurements show that the shutdown and startup operations may appear in any operational conditions and the frequency of such operations could be considerable. Although design standards require fatigue design checks for the transient load processes induced by startup and shutdown operations, relevant publications addressing this issue are very limited in particular for floating wind turbines. This paper focuses on analyzing the importance of startup and shutdown induced transient load processes on fatigue damage in the tower of two MW-level horizontal axis semi-submersible wind turbines. The analysis is carried on by comparing short-term fatigue damage in several environmental conditions with and without the startup and shutdown induced transient load processes. It is found that, in many environmental conditions, startup and/or shutdown operations may make an increase in short-term fatigue damage by 10% to 100%, while in some situations, the fatigue damage may be increased by up to 200%. The importance of the transient load processes on long-term fatigue damage is related to the occurrence frequency of startup and shutdown events. Publicly available data indicate that the average time between two consecutive shutdown events might be less than 39 h. However, more data and analysis are needed regarding these issues

Comparative analysis of numerically simulated and experimentally measured motions and sectional forces and moments in a floating wind turbine hull structure subjected to combined wind and wave loads

Multi-body time-domain finite element models, which implement a recently developed numerical approach for determining forces and moments in floaters, are developed to simulate rigid-body motions and sectional forces and moments of a reference 5-MW braceless semi-submersible wind turbine in turbulent winds and irregular waves corresponding to below rated, at rated and above rated conditions. The simulated responses are compared with measurements of a 1:30 scaled model test using a real-time hybrid testing approach. In general, agreement between simulations and measurements are very good. Differences in spectral densities of the measurements and simulations have been quantified while the reasons for the differences have been thoroughly analyzed and discussed based on comparisons of measurements in different conditions and numerical parametrical study. Effects of non-linear wave excitation loads and drag forces on the rigid-body motions and sectional forces and moments are analyzed while dominant load components in fore-aft bending moments in five cross-sections in the hull of the reference model are identified. The interface between the pontoons and central column of the reference model is identified as the most critical part. Both low frequency and wave frequency load effect should be accounted for. Mean forces and moments from wind and waves result in a change in configuration of mean wetted body surface of the hull when compared to its configuration in calm water. This may result in a considerable change in resultant sectional forces and moments even though change in resultant of the hydro pressure forces on whole of the wetted body surface could be very limited. For the analyzed model, simulated fore-aft bending moments of the model in wind and waves could be obtained by superimposing the results for wind only condition, and wave only condition except that the corresponding averaged wind induced forces and moments should be applied on the numerical model. This simplification can significantly reduce number of cases of short-term analysis required in long-term analysis. However, applicability of the simplification should be analyzed case by case in particular for a blunt structure with relatively large volume of displaced water in waves with relatively small wave length. Analysis and discussions given in this paper are based on available measurements of the model test. Hydroelastisity and structural vibration of the columns and pontoons of the hull are not accounted for by the numerical and experimental models. Suggestions for design of future model tests are given in this paper

Development and verification of a time-domain approach for determining forces and moments in structural components of floaters with an application to floating wind turbines

Structural design of the floater is an important aspect in developing cost efficient and reliable floating wind turbines. It is difficult to well account for the effect of strong non-linear dynamic characteristics and transient loading events, e.g. wind turbine faults, of floating wind turbines in a frequency-domain finite element analysis. The time-domain approach which implements the Morison's formula cannot accurately account for the hydrodynamic loads on the hull of floating wind turbines. While, the conventional hybrid frequency-time domain approach (based on the potential flow theory) fails to capture structural responses of the hulls since a rigid-body global model rather than a finite element model of the hull is employed. The present paper deals with the development and verification of a time-domain approach that can be easily implemented in various state-of-the-art computer codes for wind turbine analysis, e.g. Simo/Riflex/Aerodyn, OrcaFlex and FAST + CHARM3D, to extend their capabilities to analyze global forces and moments in structural components of a generic floater subject environmental loads from e.g. wind and waves. The global forces and moments in the structural components might be used as inputs of design formulas for structural strength design checks and/or used as boundary conditions in a sub-model finite element analysis to determine structural responses such as stresses. The proposed approach focuses on modeling of the inertia and external loads on the hull and mapping of the loads in the finite element model of the hull. In the proposed approach, floating wind turbines are considered as a system of several structural components, e.g. blades, rotational shaft, nacelle, tower, mooring lines, columns, pontoons and braces, rather than one rigid-body, while a finite element model for the hull is developed to represent the global stiffness of the structural components. The external and inertial loads on the hull are modeled as distributed loads rather than the integrated forces and moments. The conventional hybrid frequency-time domain approach, which is available in the state-of-the-art computer codes, is implemented to model the hydrodynamic loads on each structural component with essential modifications with respect to the corresponding hydrodynamic coefficients, e.g. added mass and potential damping coefficients and wave excitation forces. Approaches for modeling the hydrostatic pressure forces, gravity loads, drag forces and inertial loads on each structural component are also illustrated. Second order and higher order terms of the hydrostatic and hydrodynamic loads and the hydroelasticity effects are not accounted for in the present paper but can be further included. So far, the proposed approach has been implemented in the computer code Simo/Riflex/Aerodyn to analyze global forces and moments in the hull of a semi-submersible wind turbine. Good agreement between the reference values and the simulation results has been observed and indicates that the developed time-domain numerical models are reliable. The simulation results show that the low-frequency aerodynamic loads and fluctuations of hydrostatic pressure forces on and gravity of the floating wind turbine are important contributions to the structural responses, in particular, in the low-frequency range

Effect of Flap Type Wave Energy Converters on the Response of a Semi-Submersible Wind Turbine in Operational Conditions

In the present paper the effect of flap type wave energy converters on the response of a floating semi-submersible wind turbine is investigated and reported. Two different layouts with regard to the number of rotating flaps that are utilized are considered and compared with the case of a pure floating semi-submersible wind turbine. Comparisons of response in terms of stability, motions and internal loads are made for selected environmental conditions. The combined operation of the rotating flaps results in an increase of the produced power without affecting significantly selected critical response quantities of the semi-submersible platform

Effect of Flap Type Wave Energy Converters on the Response of a Semi-Submersible Wind Turbine in Operational Conditions

In the present paper the effect of flap type wave energy converters on the response of a floating semi-submersible wind turbine is investigated and reported. Two different layouts with regard to the number of rotating flaps that are utilized are considered and compared with the case of a pure floating semi-submersible wind turbine. Comparisons of response in terms of stability, motions and internal loads are made for selected environmental conditions. The combined operation of the rotating flaps results in an increase of the produced power without affecting significantly selected critical response quantities of the semi-submersible platform

Stochastic dynamic load effect and fatigue damage analysis of drivetrains in land-based and TLP, spar and semi-submersible floating wind turbines

This paper deals with the feasibility of using a 5 MW drivetrain which is designed for a land-based turbine, on floating wind turbines. Four types of floating support structures are investigated: spar, TLP and two semi-submersibles. The fatigue damage of mechanical components inside the gearbox and main bearings is compared for different environmental conditions, ranging from cut-in to cut-out wind speeds. For floating wind turbines, representative wave conditions are also considered. All wind turbines are ensured to follow similar power curves, but differences in the control system (integral to different concepts) are allowed. A de-coupled analysis approach is employed for the drivetrain response analysis. First, an aero-hydro-servo-elastic code is employed for the global analysis. Next, motions, moments and forces from the global analysis are applied on the gearbox multi body model and the loads on gears and bearings are obtained. The results suggest that the main bearings sustain more damage in floating wind turbines than on land-based. The highest main bearing damage is observed for the spar floating wind turbine. The large wave induced axial load on the main shaft is found to be the primary reason of this high damage in the spar wind turbine. Apart from the main bearings - which are located on the main shaft outside the gearbox - other bearings and gears inside the gearbox hold damages in floating wind turbines equal or even less than in the land-based turbine. It is emphasized that the results presented in this study are based on a drivetrain with two main bearings, which considerably reduces the non-torque loads on the gearbox.acceptedVersio