Optimal control-based inverse determination of electrode distribution for electroosmotic micromixer

This paper presents an optimal control-based inverse method used to determine the distribution of the electrodes for the electroosmotic micromixers with external driven flow from the inlet. Based on the optimal control method, one Dirichlet boundary control problem is constructed to inversely find the optimal distribution of the electrodes on the sidewalls of electroosmotic micromixers and achieve the acceptable mixing performance. After solving the boundary control problem, the step-shaped distribution of the external electric potential imposed on the sidewalls can be obtained and the distribution of electrodes can be inversely determined according to the obtained external electric potential. Numerical results are also provided to demonstrate the effectivity of the proposed method

Trifluorobenzamidine prevents allergic rhinitis by regulating IgE, IL-4 and IL-5 in T-cells

Purpose: To investigate the effect of trifluorobenzamidine (TBI) on a mouse model of ovalbumin (OVA)- induced allergic rhinitis. Methods: Allergic rhinitis was established in mice via sensitization on days 1, 5 and 14 through intraperitoneal injection of OVA (100 μg) in PBS. On day 15, the mice were subjected to intranasal exposure to OVA (1.5 mg dissolved in PBS). Prior to 10 days of intranasal exposure to OVA, the micewere treated with TBI at doses of 5, 10 and 20 μg/kg. Cytokine levels were determined using enzymelinked immunosorbent assay (ELISA) kits, while cyclooxygenase (COX)-2 and caspase-1 activity were assayed with western blotting. Results: Treatment with TBI significantly (p < 0.05) reduced OVA-mediated increases in nasal rub scores, and decreased serum levels of IgE, TNF-α, thymic stromal lymphopoietin (TSLP), IL-1β and histamine in mice. It also significantly regulated spleen weight and IL-4 secretion (p < 0.05) in OVAadministered mice. TBI significantly downregulated the expressions of IL-5, IL-13, TNFα, TSLP, IL-1β and IL-6 (p < 0.05). Administration of TBI caused a marked reduction in OVA-mediated increase in caspase-1 activity in mice intranasal tissues, and also significantly reduced OVA-induced excessive production of MIP-2 and ICAM-1 (p < 0.05). Moreover, TBI prevented OVA-induced infiltration of eosinophils and mast cells into intranasal tissues (p < 0.05). Conclusion: TBI reduces levels of IgE and various pro-inflammatory cytokines in OVA-administered mice. It also regulates Th1:Th2 ratio, inhibited activity of caspase-1, suppressed mast cell/eosinophil infiltration and reduced ICAM-1 and MIP-2 levels. Therefore, TBI possesses inhibitory potential against rhinitis allergy, and thus can potentially be developed as a new treatment strategy for asthma. Keywords: Trifluorobenzamidine, Anti-inflammation, Allergic rhinitis, Cytokines, Caspase-1, Itchin

Ultrasonic Assisted Machining of Nickel-Based Superalloy Inconel 718

Inconel 718 has been widely used in industries because of its excellent mechanical properties. However, the machining process, particularly the turning/grinding, of Inconel 718 is still costly due to high cutting force and heavy tool damage. Fortunately, a promising material removal technique, that is, ultrasonic-assisted turning/grinding (called UAT/UAG for simplicity), could potentially play a great role in the high efficiency precision machining of Inconel 718 due to its excellent features such as smaller turning/grinding force, better surface quality, longer tool working life and lower heat generation. However, few attempts have been done on UAT/UAG of Inconel 718. Therefore, in this work, in order to confirm the feasibility of machining Inconel 718 by UAT/UAG, experimental apparatus/equipment has at first been constructed by installing an ultrasonic cutting-unit/spindle on a NC lathe/surface grinder for UAT/UAG operations, and then experimental investigations have been performed to elucidate the fundamental machining characteristics involving Inconel 718 workpiece including the effects of the ultrasonic vibration and the cutting/grinding speed on the work-surface finish, the machining force and temperature, the chip formation, the tool/wheel wears and so on. The obtained results show that grinding forces and surface roughness were decreased in UAT/UAG

The effect on the seasonal dynamics of soil N transformation resulting from biochar application in karst mountains

Nitrogen (N) is frequently a limiting element for primary productivity in karst ecosystems due to its low availability. N mineralization drives N availability and is important for improving N use efficiency in soils. While the use of biochar in agricultural and forest ecosystems has attracted great attention recently, little has been reported on the seasonal dynamics of soil N transformation in karst and its response to biochar application. Therefore, we conducted a pot experiment over 1 year using two types of biochar (rice husk biochar and wood biochar) as soil amendments. The results demonstrated that in the karst mountain region, the soil had the highest content of mineral N (19.41 mg/kg) during summer and the lowest content of mineral nitrogen (3.74 mg/kg) during winter. There was a significant positive correlation (p < 0.01) between soil mineral N content and temperature, and between soil temperature and urease activity. Thus, the higher temperatures during summer enhance soil urease activity, making it easier for soil N mineralization to occur, and increasing soil mineral N content. The soil mineral N content of the CK treatment was 2.61–209.42% higher than the other treatments, indicating that the biochar application reduced the soil mineral N content, which was supported by the negative net N mineralization. This may be due to biochar facilitating the adsorption and immobilization of nitrogen. The soil mineral N content of rice husk biochar was significantly higher than that of woody biochar by 109.55%, indicating that woody biochar would adsorb more N or more readily stimulate N immobilization than rice husk biochar. Furthermore, soil N immobilization (negative net N mineralization) after biochar application varied according to the season. The higher temperatures during summer promoted soil N immobilization more with biochar application. These results are crucial to understanding soil N transformation in karst mountains and guiding effective soil management

Sphere forming mechanisms in vibration-assisted ball centreless grinding

This paper aims to clarify the sphere forming mechanisms in vibration-assisted ball centreless grinding, a new technique for effectively processing balls using ultrasonic vibrations. Based on a comprehensive analysis of the ball rotation motion, geometrical arrangement and stiffness of the whole grinding system, a reliable mechanics model was successfully developed for predicting the sphere forming process. Relevant experiments conducted showed that the model had captured the mechanics and the major sphere forming mechanisms in ball centreless grinding. It was found that the ball whole surface can be well ground with a high accuracy, while efficiency is much enhanced compared with that in the traditional methods. The ball rotational speed which is controlled by the ultrasonic regulator has a great impact on final sphericity, and the speed controlled by the ultrasonic shoe dominates the whole processing time. To achieve a stable and high precision grinding, the ball needs to rotate rhythmically, and the wheel feed per step and the ball location angle should be controlled in a critical range

Exendin-4 attenuates ischemia-induced ventricular arrhythmias in rats

Background: Glucagon-like peptide-1 and its receptor agonist-exendin-4 (Ex-4) have been shown to provide beneficial effects for cardiovascular diseases. This study investigated the effects of Ex-4 on ischemia-induced ventricular arrhythmias in rats. Methods: Anesthetized male rats were once treated with Ex-4 (5 &#956;g/kg, i.v.) 1 h before ischemia in the absence and/or presence of 5-hydroxydecanoic acid (5-HD, 10 mg/kg, i.v., a specific inhibitor of mitochondrial ATP-sensitive potassium [KATP] channels) which were once injected 10 min before ischemia. And then subjected to ischemia for 30 min. Ventricular arrhythmias were assessed. Results: During the 30-min ischemia, Ex-4 significantly reduced the incidence of ventricular fibrillation (VF) (p < 0.05). The duration of ventricular tachycardia (VT) + VF, the number of VT + VF episodes and the severity of arrhythmias were all significantly reduced by Ex-4 compared to those in myocardial ischemia group (p < 0.05 for all). Administration of 5-HD abolished the protective effects of Ex-4 on VF incidence, the duration of VT + VF, the number of VT + VF episodes and the severity of arrhythmias (p < 0.05 for all). Conclusions: This study suggested that Ex-4 could attenuate ischemia-induced ventricular arrhythmias in rats in which mitochondrial KATP channels may be involved