Self-Retracting Motion of Graphite Microflakes

We report the observation of a novel phenomenon, the self-retracting motion of graphite, in which tiny flakes of graphite, after being displaced to various suspended positions from islands of highly orientated pyrolytic graphite, retract back onto the islands under no external influences. Our repeated probing and observing such flakes of various sizes indicate the existence of a critical size of flakes, approximately 35 micrometer, above which the self-retracting motion does not occur under the operation. This helps to explain the fact that the self-retracting motion of graphite has not been reported, because samples of natural graphite are typical larger than this critical size. In fact, reports of this phenomenon have not been found in the literature for single crystals of any kinds. A model that includes the static and dynamic shear strengths, the van der Waals interaction force, and the edge dangling bond interaction effect, was used to explain the observed phenomenon. These findings may conduce to create nano-electromechanical systems with a wide range of mechanical operating frequency from mega to giga hertzs

Salmon Calcitonin Exerts an Antidepressant Effect by Activating Amylin Receptors

Depressive disorder is defined as a psychiatric disease characterized by the core symptoms of anhedonia and learned helplessness. Currently, the treatment of depression still calls for medications with high effectiveness, rapid action, and few side effects, although many drugs, including fluoxetine and ketamine, have been approved for clinical usage by the Food and Drug Administration (FDA). In this study, we focused on calcitonin as an amylin receptor polypeptide, of which the antidepressant effect has not been reported, even if calcitonin gene-related peptides have been previously demonstrated to improve depressive-like behaviors in rodents. Here, the antidepressant potential of salmon calcitonin (sCT) was first evaluated in a chronic restraint stress (CRS) mouse model of depression. We observed that the immobility duration in CRS mice was significantly increased during the tail suspension test and forced swimming test. Furthermore, a single administration of sCT was found to successfully rescue depressive-like behaviors in CRS mice. Lastly, AC187 as a potent amylin receptor antagonist was applied to investigate the roles of amylin receptors in depression. We found that AC187 significantly eliminated the antidepressant effects of sCT. Taken together, our data revealed that sCT could ameliorate a depressive-like phenotype probably via the amylin signaling pathway. sCT should be considered as a potential therapeutic candidate for depressive disorder in the future

Sudden drop of fractal dimension of electromagnetic emissions recorded prior to significant earthquake

The variation of fractal dimension and entropy during a damage evolution process, especially approaching critical failure, has been recently investigated. A sudden drop of fractal dimension has been proposed as a quantitative indicator of damage localization or a likely precursor of an impending catastrophic failure. In this contribution, electromagnetic emissions recorded prior to significant earthquake are analysed to investigate whether they also present such sudden fractal dimension and entropy drops as the main catastrophic event is approaching. The pre-earthquake electromagnetic time series analysis results reveal a good agreement to the theoretically expected ones indicating that the critical fracture is approaching

Licochalcone A Protects the Blood–Milk Barrier Integrity and Relieves the Inflammatory Response in LPS-Induced Mastitis

Background/Aims: Mastitis is an acute clinical inflammatory response. The occurrence and development of mastitis seriously disturb women's physical and mental health. Licochalcone A, a phenolic compound in Glycyrrhiza uralensis, has anti-inflammatory properties. Here, we examined the effect of licochalcone A on blood-milk barrier and inflammatory response in LPS-induced mice mastitis.Methods:In vivo, we firstly established mice models of mastitis by canal injection of LPS to mammary gland, and then detected the effect of licochalcone A on pathological indexes, inflammatory responses and blood-milk barrier in this model. In vivo, Mouse mammary epithelial cells (mMECs) were treated with licochalcone A prior to the incubation of LPS, and then the inflammatory responses, tight junction which is the basic structure of blood-milk barrier were analyzed. Last, we elucidated the anti-inflammatory mechanism by examining the activation of mitogen-activated protein kinase (MAPK) and AKT/NF-κB signaling pathways in vivo and in vitro.Result: The in vivo results showed that licochalcone A significantly decreased the histopathological impairment and the inflammatory responses, and improved integrity of blood-milk barrier. The in vitro results demonstrated that licochalcone A inhibited LPS-induced inflammatory responses and increase the protein levels of ZO-1, occludin, and claudin3 in mMECs. The in vivo and in vitro mechanistic study found that the anti-inflammatory effect of licochalcone A in LPS-induced mice mastitis was mediated by MAPK and AKT/NF-κB signaling pathways.Conclusions and Implications: Our experiments collectively indicate that licochalcone A protected against LPS-induced mice mastitis via improving the blood–milk barrier integrity and inhibits the inflammatory response by MAPK and AKT/NF-κB signaling pathways

Polydatin Prevents Lipopolysaccharide (LPS)-Induced Parkinson's Disease via Regulation of the AKT/GSK3β-Nrf2/NF-κB Signaling Axis

Parkinson's disease (PD) is a common neurodegenerative disease characterized by selective loss of dopaminergic neurons in the substantia nigra (SN). Neuroinflammation induced by over-activation of microglia leads to the death of dopaminergic neurons in the pathogenesis of PD. Therefore, downregulation of microglial activation may aid in the treatment of PD. Polydatin (PLD) has been reported to pass through the blood-brain barrier and protect against motor degeneration in the SN. However, the molecular mechanisms underlying the effects of PLD in the treatment of PD remain unclear. The present study aimed to determine whether PLD protects against dopaminergic neurodegeneration by inhibiting the activation of microglia in a rat model of lipopolysaccharide (LPS)-induced PD. Our findings indicated that PLD treatment protected dopaminergic neurons and ameliorated motor dysfunction by inhibiting microglial activation and the release of pro-inflammatory mediators. Furthermore, PLD treatment significantly increased levels of p-AKT, p-GSK-3βSer9, and Nrf2, and suppressed the activation of NF-κB in the SN of rats with LPS-induced PD. To further explore the neuroprotective mechanism of PLD, we investigated the effect of PLD on activated microglial BV-2 cells. Our findings indicated that PLD inhibited the production of pro-inflammatory mediators and the activation of NF-κB pathways in LPS-induced BV-2 cells. Moreover, our results indicated that PLD enhanced levels of p-AKT, p-GSK-3βSer9, and Nrf2 in BV-2 cells. After BV-2 cells were pretreated with MK2206 (an inhibitor of AKT), NP-12 (an inhibitor of GSK-3β), or Brusatol (BT; an inhibitor of Nrf2), treatment with PLD suppressed the activation of NF-κB signaling pathways and the release of pro-inflammatory mediators in activated BV-2 cells via activation of the AKT/GSK3β-Nrf2 signaling axis. Taken together, our results are the first to demonstrate that PLD prevents dopaminergic neurodegeneration due to microglial activation via regulation of the AKT/GSK3β-Nrf2/NF-κB signaling axis

Atomic library optimization for pulse ultrasonic sparse signal decomposition and reconstruction

Compressive sampling of pulse ultrasonic NDE signals could bring significant savings in the data acquisition process. Sparse representation of these signals using an atomic library is key to their interpretation and reconstruction from compressive samples. However, the obstacles to practical applicability of such representations are: large size of the atomic library and computational complexity of the sparse decomposition and reconstruction. To help solve these problems, we develop a method for optimizing the ranges of parameters of traditional Gabor-atom library to match a real pulse ultrasonic signal in terms of correlation. As a result of atomic-library optimization, the number of the atoms is greatly reduced. Numerical simulations compare the proposed approach with the traditional method. Simulation results show that both the time efficiency and signal reconstruction energy error are superior to the traditional one even with small-scale atomic library. The performance of the proposed method is also explored under different noise levels. Finally, we apply the proposed method to real pipeline ultrasonic testing data, and the results indicate that our reduced atomic library outperforms the traditional library.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This proceeding appeared in Song, Shoupeng, Yingxue Li, and Aleksandar Dogandžić. "Atomic library optimization for pulse ultrasonic sparse signal decomposition and reconstruction." In AIP Conference Proceedings, vol. 1706, no. 1, p. 180008. AIP Publishing LLC, 2016, and may be found at DOI: 10.1063/1.4940638. Copyright 2016 AIP Publishing LLC. Posted with permission

A Rapid Self-Alignment Strategy for a Launch Vehicle on an Offshore Launching Platform

To reduce the impact of offshore launching platform motion and swaying on the self-alignment accuracy of a launch vehicle, a rapid self-alignment strategy, which involves an optimal combination of anti-swaying coarse alignment (ASCA), backtracking navigation, and reverse Kalman filtering is proposed. During the entire alignment process, the data provided by the strapdown inertial navigation system (SINS) are stored and then applied to forward and backtrack self-alignment. This work elaborates the basic principles of coarse alignment and then analyzes the influence of ASCA time on alignment accuracy. An error model was built for the reverse fine alignment system. The coarse alignment was carried out based on the above work, then the state of the alignment system was retraced using the reverse inertial navigation solution and reverse Kalman filtering with the proposed strategy. A cycle-index control function was designed to approximate strict backtracking navigation. Finally, the attitude error was compensated for after the completion of the first and the last forward navigation. To demonstrate the effectiveness of the proposed strategy, numerical simulations were carried out in a scenario of launch vehicle motion and swaying. The proposed strategy can maximize the utilization of SINS data and hence improve the alignment accuracy and further reduce the alignment time. The results show that the fully autonomous alignment technology of the SINS can replace the complex optical aiming system and realize the determination of the initial attitude of a launch vehicle before launch

Measurement of the Thermal Effect of Standing Surface Acoustic Waves in Microchannel by Fluoresence Intensity

Temperature is an important parameter for many medical and biological applications. It is key to measuring the temperature of acoustofluidics devices for controlling the device’s temperature. In this paper, Rhodamine B was used to measure the temperature change of the microchannel induced by the SSAWs’ thermal effect in microfluidics. A thermocouple was integrated into the microfluidics device to calibrate the relationship between the fluorescent intensity ratios of Rhodamine B and the temperature. Then, the fluid temperature in the microchannel heated by the SSAWs was measured by the fluorescent signal intensity ratio in the acoustofluidics device. The fluid temperature with different input voltages and different flow rates was measured. The results show that SSAWs can heat the still fluid rapidly to 80 °c, and the flow rates will influence the temperature of the fluid. The results will be useful for precisely controlling the temperature of acoustofluidics devices