Search

In the present study, effect of ultrasonic impact treatment (UIT) on the microstructural characterization and mechanical properties of 316L stainless steel (hereinafter referred to as 316L) was investigated experimentally. The fatigue fracture mechanism of 316L before and after UIT was revealed. The experimental results indicated that the martensitic grain size induced at the impact edge was about 2.00 Å. The surface modified 316L formed a gradient nanostructure and induced a martensitic phase transformation. The hardness of the surface layer of the modified 316L was twice the hardness of its matrix. The tensile strengths of 316L before and after UIT were 576 MPa and 703 MPa, respectively. The stretching stripes of 316L were more disordered after UIT. The fatigue strengths of 316L before and after UIT were 267 MPa and 327 MPa, respectively. The fatigue cracking of 316L started from the austenite grain boundaries. The fatigue fracture surface was relatively rough. The fatigue crack sources of the modified 316L came from internal inclusions. The inclusions were oxides dominated by SiO2. As the stress range increased, the crack initiation site migrated to the interior and the fatigue fracture surface became flatter. [ABSTRACT FROM AUTHOR]

The present research focused on identifying necroptosis‐related differentially expressed genes (NRDEGs) in spinal cord injury (SCI) to highlight potential therapeutic and prognostic target genes in clinical SCI. Three SCI‐related datasets were downloaded, including GSE151371, GSE5296 and GSE47681. MSigDB and KEGG datasets were searched for necroptosis‐related genes (NRGs). Differentially expressed genes (DEGs) and NRGs were intersected to obtain NRDEGs. The MCC algorithm was employed to select the first 10 genes as hub genes. A protein–protein interaction (PPI) network related to NRDEGs was developed utilizing STRING. Several databases were searched to predict interactions between hub genes and miRNAs, transcription factors, potential drugs, and small molecules. Immunoassays were performed to identify DEGs using CIBERSORTx. Additionally, qRT‐PCR was carried out to verify NRDEGs in an animal model of SCI. Combined analysis of all datasets identified 15 co‐expressed DEGs and NRGs. GO and KEGG pathway analyses highlighted DEGs mostly belonged to pathways associated with necroptosis and apoptosis. Hub gene expression analysis showed high accuracy in SCI diagnosis was associated with the expression of CHMP7 and FADD. A total of two hub genes, i.e. CHMP7, FADD, were considered potential targets for SCI therapy. [ABSTRACT FROM AUTHOR]

The traditional trajectory prediction models have the problems of large model simplification and less consideration. Combined with the characteristics of flight trajectory continuity, time series and interactivity, a trajectory prediction model based on bidirectional long short term memory(Bi-LSTM) neural network is proposed. The position, heading, pitch, roll and relative information of the intruder UAV are simultaneously used as the input of the trajectory prediction model, which is more in line with the true trajectory change law. The established Bi-LSTM based trajectory prediction model is trained with adaptive learning rate learning algorithm considering momentum and speed, and performed with simulation contrastive analysis with trajectory prediction model based on Elman neural network. The results show that, compared with the trajectory prediction model based on Elman neural network, the average absolute error of the proposed model predicted by 200 points in different directions is less than 4 m, the 3D prediction effect is better, and can perform the trajectory prediction more accurately.

The human stress hormones catecholamines play a critical role in communication between human microbiota and their hosts and influence the outcomes of bacterial infections. However, it is unclear how M. tuberculosis senses and responds to certain types of human stress hormones. In this study, we screened several human catecholamine stress hormones (epinephrine, norepinephrine, and dopamine) for their effects on Mycobacterium growth. Our results showed that epinephrine significantly stimulated the growth of M. tuberculosis in the serum-based medium as well as macrophages. In silico analysis and molecular docking suggested that the extra-cytoplasmic domain of the MprB might be the putative adrenergic sensor. Furthermore, we showed that epinephrine significantly enhances M. tuberculosis biofilm formation, which has distinct texture composition, antibiotic resistance, and stress tolerance. Together, our data revealed the effect and mechanism of epinephrine on the growth and biofilm formation of M. tuberculosis, which contributes to the understanding of the environmental perception and antibiotic resistance of M. tuberculosis and provides important clues for the understanding of bacterial pathogenesis and the development of novel antibacterial therapeutics. [ABSTRACT FROM AUTHOR]

The computational fluid dynamics (CFD) combined with radial basis function (RBF) method were adopted to obtain the response surface of the Muszynska nonlinear seal force model coefficient with two variables: eccentricity and rotation speed. During the implementation of the simulation, three coefficients of the seal force model were calculated in each sub-step according to the current state of the rotor-bearing seal system; following which the rotor dynamics analysis with varying parameters was realized. As with the traditional constant coefficient method, the first-order critical speed of the system was obtained, and the bifurcation point and oil film whirl of the system response were identified. The difference is that the coefficients of the traditional method ordinarily do not change with the state of the system. Comparing the results of the varying parameter method with those of the traditional method, it can be seen that the speeds of the system corresponding to the bifurcation and oil film whirl are different. The varying parameter rotor dynamics simulation method proposed in this paper provides a new way of analyzing the nonlinear characteristics of rotor-bearing-seal systems. [ABSTRACT FROM AUTHOR]

The recovery of lower-urinary-tract activity is a top priority for patients with spinal-cord injury. Historically, locomotor training improved micturition function in both patients with spinal cord injury and animal models. We explore whether training augments such as the supraspinal control of the external urethral sphincter results in enhanced coordination in detrusor-sphincter activity. We implemented a clinically relevant contusive spinal-cord injury at the 12th thoracic level in rats and administered forced wheel running exercise for 11 weeks. Awake rats then underwent bladder cystometrogram and sphincter electromyography recordings to examine the micturition reflex. Subsequently, pseudorabies-virus-encoding red fluorescent protein was injected into the sphincter to trans-synaptically trace the supraspinal innervation of Onuf's motoneurons. Training in the injury group reduced the occurrence of bladder nonvoiding contractions, decreased the voiding threshold and peak intravesical pressure, and shortened the latency of sphincter bursting during voiding, leading to enhanced voiding efficiency. Histological analysis demonstrated that the training increased the extent of spared spinal-cord tissue around the epicenter of lesions. Compared to the group of injury without exercise, training elicited denser 5-hydroxytryptamine-positive axon terminals in the vicinity of Onuf's motoneurons in the cord; more pseudorabies virus-labeled or c-fos expressing neurons were detected in the brainstem, suggesting the enhanced supraspinal control of sphincter activity. Thus, locomotor training promotes tissue sparing and axon innervation of spinal motoneurons to improve voiding function following contusive spinal-cord injury. [ABSTRACT FROM AUTHOR]

Japanese encephalitis virus (JEV) is one of the most important members of the flavivirus family. It is a typical zoonotic pathogen that has caused substantial social and economic losses worldwide. The relation between JEV-induced immunosuppression and inflammatory responses has not been thoroughly investigated. In this study, cells infiltrating the brain tissue of JEV-infected mice were mainly identified as monocytic myeloid-derived suppressor cells (M-MDSCs), which subsequently differentiated into CD3+ macrophages. Co-culture with T cells showed that both splenic M-MDSCs and brain infiltrated M-MDSCs isolated from JEV-infected mice inhibited T cell proliferation through ARG1 and iNOS. The splenectomy model revealed that JEV-induced M-MDSCs were mainly derived from bone marrow and migrated to the spleen and central nervous system (CNS). The results of the transcriptome analysis and IRF7-deficient mice indicated that the ZBP1-IRF7 signaling pathway stimulated by JEV RNA played a central role in the induction of M-MDSCs. M-MDSCs migrated into the CNS through the chemokine CCL2/N-CCL2 derived from astrocytes and brain infiltrated M-MDSCs differentiated into CD3+ macrophages through a mechanism mediated by M-CSF, IL-6 and IFN-γ in the brain microenvironment. These findings provide evidence for the mechanism that JEV regulates the differentiation of M-MDSCs and thereby exacerbates pathogenicity, which represents a potential therapeutic target for Japanese encephalitis (JE). [ABSTRACT FROM AUTHOR]

In humans, telomere length in proliferating tissues shortens with age--a process accelerated with age-related diseases. Thus, telomere length and attrition with age in the nonhuman primate may serve as a useful paradigm for understanding telomere biology in humans. We examined telomere parameters in tissues of young and old Macaca fascicularis and compared them with several tissues from humans. Macaque telomeres were variable in length and exhibited partial synchrony (equivalence) within animals. They were longer than humans, partially because of longer subtelomeric segments. As skeletal muscle telomere length was unchanged with age, we used it as an internal reference to offset interanimal variation in telomere length. We identified age-dependent telomere attrition in lung, pancreas, skin, and thyroid. Similar to humans, telomerase activity was detected in spleen, thymus, digestive tract, and gonads. We conclude that factors that modify telomere attrition and aging in humans may also operate in the macaque.

The unique characteristics of the platelet Na/Ca exchanger, i.e., its dependence on both transmembrane Na and K gradients, render it highly sensitive to Na pump inhibition. In this project, we observed that the human megakaryocytic cell line CHRF-288 expresses both the [[alpha].sub.1]- and [[alpha].sub.3]-isoforms of the Na-K-ATPase. Inhibition of the Na pump increased the RNA and protein expressions of sarco(endo)plasmic reticulum Ca-ATPase 2b, cytosolic Na and Ca, and the freely exchangeable Ca in the endoplasmic reticulum. These changes occurred in concert with diminished store-operated Ca entry and an increase in the maximal activity of the Na/Ca exchanger. Inhibition of the Na pump by ouabain was more effective in inducing these changes than diminishing medium K. Collectively, these observations point to an integrative effort to counteract the impact of Na pump inhibition by Ca sequestration into the endoplasmic reticulum, diminished Ca entry, and increased activity of the Na/Ca exchanger. The implications of these findings in platelet biology are discussed. platelets; thrombosis; potassium; stroke

Foams are substances widely used the foam flooding technology, which aim to greatly improve the residual oil recovery. In the present study, we perform a comprehensive investigation on the oil removal process driven by the foam embedded with magnetic particles, under the action of the magnetic force. The experiment shows that the addition of magnetic particles has little effect on the stability of the foam. During the motion of the foam, its maximum displacement and maximum acceleration are fully explored. Such factors as the volume of the foam, the volume of the oil droplet, the mass concentration of magnetic particles, and the Young's contact angle of surfactant on solid are surveyed in detail. The function curves of the maximum displacement and the maximum acceleration with respect to these variables are obtained in the experiment, and the selection of some optimal parameters is advised. Moreover, the dimensional analysis has been conducted and several scaling laws are given, which are in agreement with the experimental results. These findings are beneficial to understand the oil displacement with the aid of magnetic field, which also provide some inspirations on drug delivery, robots and micro-fluidics. [ABSTRACT FROM AUTHOR]