Effects of a Pseudomonas H6 surfactant on rainbow trout and Ichthyophthirius multifiliis: In vivo exposure

The Pseudomonas H6 lipopeptide is a surfactant, which is able to eliminate various parasitic pathogens including the ciliate Ichthyophthirius multifiliis in vitro. This suggests an application for aquaculture purposes. However, further information on efficacy of the compound and possible immune modulation of surfactant-exposed fish should be gathered before usage at farm level is considered. We performed an in vivo infection experiment using rainbow trout fry (mean weight 4.6 g, mean length 7.6 cm) as hosts and I. multifiliis theronts as the parasitic pathogen. We compared infection level, immune gene regulation and immune cell density in gills of 1) no exposed control fish, 2) parasite exposed but untreated fish, 3) surfactant treated fish without parasite exposure, and 4) fish exposed both to parasites and surfactant. The surfactant concentration was 10 mg/L, the infection dosage 1000 theronts/fish and the exposure period 6 h. The parasite infection was recorded and samples were taken from rainbow trout gills at day 0 and 10 post-exposure. We performed an immunohistochemical investigation (detecting cells positive for MHC II, SAA, CD8, IgM, IgT and IgD) and measured the expression of genes encoding cathelidin-1, CD8, hepcidin, IFN γ, IgDs, IL-1β, IL-6 and SAA. Theront exposed fish (without surfactant treatment) became heavily infected whereas concomitant surfactant treatment (10 mg/l), along with parasite exposure, could prevent infection. A significant inflammation (upregulation of il-1β, il6, ifn γ, cathelicidin, hepcidin) was elicited in non-treated and parasite exposed fish but it was prevented by the surfactant treatment. When investigated 10 days after treatment no immune gene regulation was seen in fish exposed to surfactant only. The therapeutic effect may be due to a direct parasitical action of the surfactant, but it cannot be excluded that a modulation of the host immune reaction may influence the infection success

Sustained Release of IGF-1 by 3D Mesoporous Scaffolds Promoting Cardiac Stem Cell Migration and Proliferation

Background/Aims: C-kit-positive cardiac stem cells (CSCs) may have potential as a treatment for cardiovascular disease. However, the low survival rates of c-kit-positive CSCs present a major challenge during the transplantation process. Methods: The hierarchical structure of the 3D cell scaffold was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and N2 adsorption-desorption isotherms. Analyses of the proliferation and migration performances of the IGF-1 scaffold on c-kit-positive CSCs were conducted by experiments including QuantiT PicoGreen dsDNA and transwell assays. Results: In this study, we synthesized for the first time a novel hierarchical macro-mesoporous silica material (denoted MS15-c) in a one-pot procedure for the release of insulin-like growth factor-1 (IGF-1) and a three-dimensional (3D) cell scaffold. Both macropores and mesopores were visible in MS15-c and enabled the sustained release of IGF-1, extending its half-life and enhancing CSC proliferation and migration. Proliferation and migration were detected by QuantiT PicoGreen dsDNA and transwell assays, respectively. Moreover, an in vivo experiment was conducted to detect heart function with the addition of MS15-c. The new strategy proposed in this paper may extend the bio-applications of 3D cell scaffolds, thus permitting the sustained release of growth factors and efficient promotion of cell proliferation. Conclusion: This work successfully demonstrated an effective strategy for the construction of MS15-c cell scaffolds with hierarchical macro-mesoporous structures. The macro-mesoporous structures gave cell scaffolds the ability to release a growth factor to facilitate cell growth, while the scaffold structure promoted cell proliferation

Dynamic pricing with service unbundling

In this study, we investigate unbundling when a firm dynamically prices a basic service, while separating the sale of a fixed-price add-on. We characterize the optimal dynamic unbundling pricing policy and investigate its structural properties. We find that the value function with unbundling increases in the degree of dependence between consumers’ reservation prices for basic service and add-on. However, there are no similar monotonicity properties for the optimal price of the basic service. For several families of commonly used joint distributions, we show that the influence of the dependence parameter on the optimal price of the basic service depends on a threshold, which is a function of the dependence parameter. Moreover, the price of the bundled service is higher under unbundling when the add-on price is high, and vice versa. Our model is then compared with the bundling model through a numerical experiment. Among most cases where unbundling outperforms, the degree of dependence is non-negative. It is further revealed that given the non-negativity of dependence, unbundling is worth practicing under the following situations: (i) the variance of the reservation price for the basic service (add-on) is low (high); (ii) the mean of the reservation price for the basic service (add-on) is high (low); (iii) the demand intensity is low; (iv) the capacity of the basic service is high; and (v) the incremental cost of the basic service (add-on) is low (high). Finally, unbundling can improve the firm's expected profit and the consumers’ surplus at the same time

Squeeze-Film Air Damping of a Five-Axis Electrostatic Bearing for Rotary Micromotors

Air-film damping, which dominates over other losses, plays a significant role in the dynamic response of many micro-fabricated devices with a movable mass suspended by various bearing mechanisms. Modeling the damping characteristics accurately will be greatly helpful to the bearing design, control, and test in various micromotor devices. This paper presents the simulated and experimental squeeze-film air damping results of an electrostatic bearing for use in a rotary high-speed micromotor. It is shown that the boundary condition to solve the three-dimensional Reynolds equation, which governs the squeeze-film damping in the air gap between the rotor and its surrounding stator sealed in a three-layer evacuated cavity, behaves with strong cross-axis coupling characteristics. To accurately characterize the damping effect, a set of multiphysics finite-element simulations are performed by computing both the rotor velocity and the distribution of the viscous damping force acting on the rotor. The damping characteristics varying with several key structure parameters are simulated and discussed to optimize the device structure for desirable rotor dynamics. An electrical measurement method is also proposed and applied to validate the numerical results of the damping coefficients experimentally. Given that the frequency response of the electric bearing is critically dependent on the damping coefficients at atmospheric pressure, a solution to the air-film damping measurement problem is presented by taking approximate curve fitting of multi-axis experimental frequency responses. The measured squeeze-film damping coefficients for the five-axis electric bearing agrees well with the numerical solutions. This indicates that numerical multiphysics simulation is an effective method to accurately examine the air-film damping effect for complex device geometry and arbitrary boundary condition. The accurate damping coefficients obtained by FEM simulation will greatly simplify the design of the five-axis bearing control system and facilitate the initial suspension test of the rotor for various micromotor devices

Fully Distributed Consensus Tracking of Stochastic Nonlinear Multiagent Systems With Markovian Switching Topologies via Intermittent Control

International audienc

The Effects of Anthropomorphism, Message Framing, and Voice Type on Unhealthy Sleep Behavior in Young Users: The Mediating Role of Risk Perception

Insufficient sleep is a severe social public health problem that can adversely affect the physical and mental health of young people. This study examined risk perceptions for unhealthy sleep behaviors and intentions for healthy sleep behaviors under different combinations of anthropomorphism, message framing, and voice type in cartoons. We used a three-factor between-subject experiment of two (anthropomorphism: anthropomorphic vs. non-anthropomorphic) × two (message framing: positive frame vs. negative frame) × two (voice type: cartoon child voice vs. adult female voice) design. We examined the effects of different audiovisual combinations of cartoon attitude, risk perception, and behavioral intention and the mediating role of risk perception. The research results show that (1) the integration of anthropomorphic design elements can positively impact users’ attitudes toward cartoons; (2) when the interface information is presented in a negative frame, anthropomorphism can more positively influence users’ attitudes toward cartoons than non-anthropomorphism; and (3) anthropomorphism, message framing, and voice type in cartoons significantly interact with risk perception. In addition, risk perception mediates the influence of anthropomorphism, message framing, and voice type on behavioral intention

How the Crosslinking Agent Influences the Thermal Stability of RTV Phenyl Silicone Rubber

In this work, a thermal degradation mechanism of room temperature vulcanized (RTV) phenyl silicone rubber that was vulcanized by different crosslinking agents was discussed. Firstly, RTV phenyl silicone rubber samples were prepared by curing hydroxyl-terminated polymethyldiphenylsiloxane via three crosslinking agents, namely, tetraethoxysilane (TEOS), tetrapropoxysilane (TPOS), and polysilazane. Secondly, the ablation properties of RTV phenyl silicone rubber were studied by the muffle roaster test and FT-IR. Thirdly, thermal stability of the three samples was studied by thermogravimetric (TG) analysis. Finally, to explore the thermal degradation mechanism, the RTV phenyl silicone rubber vulcanized by different crosslinking agents were characterized by TG analysis-mass spectrum (TG-MS) and pyrolysis gas chromatogram-mass spectrum (pyGC-MS). Results showed that the thermal stability of RTV phenyl silicone rubber is related to the amount of residual Si–OH groups. The residual Si–OH groups initiated the polysiloxane chain degradation via an ‘unzipping’ mechanism

The Protective Effects of Enalapril Maleate and Folic Acid Tablets against Contrast-Induced Nephropathy in Diabetic Rats

Background. Renal vasoconstriction, oxidative stress, endothelial dysfunction, and apoptosis are the major causes of contrast-induced nephropathy (CIN). The aim of this study was to evaluate the protective effects of enalapril maleate and folic acid tablets on CIN in diabetic rats. Methods. Thirty-two Sprague-Dawley rats were divided into four groups: CIN (C), CIN + enalapril maleate (CE), CIN + folic acid (CF), and CIN + enalapril maleate and folic acid tablets (CEF). CE, CF, and CEF rats were treated orally with enalapril maleate, folic acid, or enalapril maleate and folic acid tablets, respectively, for 5 days. CIN was induced in all groups followed by analyzed biochemical parameters, oxidative stress markers, endothelial dysfunction parameters, renal histopathology, and TUNEL staining. Results. Serum creatinine, blood urea nitrogen, and malondialdehyde levels were lower in the CEF group than in the C group. Homocysteine, superoxide dismutase, glutathione peroxidase, and nitric oxide levels were higher in the CEF group than in the C group. Histopathology scores and percentage of apoptotic kidney cells in the CEF group were significantly decreased compared with those in the C group. Conclusions. These results suggest that enalapril maleate and folic acid tablets have a protective effect against CIN in diabetic rats