Simplified Aeroelastic Model for Fluid Structure Interaction between Microcantilever Sensors and Fluid Surroundings

Fluid-structural coupling occurs when microcantilever sensors vibrate in a fluid. Due to the complexity of the mechanical characteristics of microcantilevers and lack of high-precision microscopic mechanical testing instruments, effective methods for studying the fluid-structural coupling of microcantilevers are lacking, especially for non-rectangular microcantilevers. Here, we report fluid-structure interactions (FSI) of the cable-membrane structure via a macroscopic study. The simplified aeroelastic model was introduced into the microscopic field to establish a fluid-structure coupling vibration model for microcantilever sensors. We used the finite element method to solve the coupled FSI system. Based on the simplified aeroelastic model, simulation analysis of the effects of the air environment on the vibration of the commonly used rectangular microcantilever was also performed. The obtained results are consistent with the literature. The proposed model can also be applied to the auxiliary design of rectangular and non-rectangular sensors used in fluid environments.     

Effect of Bone Mineral Density on Rotator Cuff Tear: An Osteoporotic Rabbit Model

IntroductionAn increased bone mineral density (BMD) in the proximity to tendon insertion can improve rotator cuff repair and healing. However, how a decrease of BMD in the humeral head affects the biomechanical properties of the rotator cuff tendon is still unclear. Previous studies have demonstrated ovariectomy in animals to lead to osteoporosis and decreased BMD, and Teriparatide (PTH) administration to improve BMD and strength of bone. This study aimed to explore the correlation between humeral head BMD and infraspinatus (ISP) tendon insertion strength, and if an increase in bone quantity of the humeral head can improve the strength of the rotator cuff.ResultsSignificant differences were observed in the measured humeral head BMD of the Control and OVX-PTH groups compared to the OVX-Saline group (P = 0.0004 and P = 0.0024, respectively). No significant difference was found in failure stress among the three groups, but an expected trend with the control group and OVX-PTH group presenting higher failure strength compared to the OVX-Saline group. BMD at the humeral head showed a positive linear correlation with stress (r² = 0.54). Histology results showed the superiority in OVX-PTH group ISP enthesis compared to the OVX-Saline group.ConclusionBone loss of the humeral head leads to decreased tendon/bone insertion strength of the infraspinatus tendon enthesis. Teriparatide administration can increase bone density of the humeral head and may improve the mechanical properties of the infraspinatus tendon enthesis.     

Splenic gene expression profiling in White Leghorn layer inoculated with the Salmonella enterica serovar Enteritidis

Salmonella enterica serovar Enteritidis (SE) is a foodborne pathogen that can threaten human health through contaminated poultry products. Live poultry, chicken eggs and meat are primary sources of human salmonellosis. To understand the genetic resistance of egg‐type chickens in response to SE inoculation, global gene expression in the spleen of 20‐week‐old White Leghorn was measured using the Agilent 4 × 44 K chicken microarray at 7 and 14 days following SE inoculation (dpi). Results showed that there were 1363 genes significantly differentially expressed between inoculated and non‐inoculated groups at 7 dpi (I7/N7), of which 682 were up‐regulated and 681 were down‐regulated genes. By contrast, 688 differentially expressed genes were observed at 14 dpi (I14/N14), of which 371 were up‐regulated genes and 317 were down‐regulated genes. There were 33 and 28 immune‐related genes significantly differentially expressed in the comparisons of I7/N7 and I14/N14 respectively. Functional annotation revealed that several Gene Ontology (GO) terms related to immunity were significantly enriched between the inoculated and non‐inoculated groups at 14 dpi but not at 7 dpi, despite a similar number of immune‐related genes identified between I7/N7 and I14/N14. The immune response to SE inoculation changes with different time points following SE inoculation. The complicated interaction between the immune system and metabolism contributes to the immune responses to SE inoculation of egg‐type chickens at 14 dpi at the onset of lay. GC, TNFSF8, CD86, CD274, BLB1 and BLB2 play important roles in response to SE inoculation. The results from this study will deepen the current understanding of the genetic response of the egg‐type chicken to SE inoculation at the onset of egg laying.     

A new genus of Coelotinae (Araneae,Agelenidae) from southern China

One new genus of the spider subfamily Coelotinae, Flexicoelotes gen. n., with five new species is described from southern China: Flexicoelotes huyunensis sp. n. (female), Flexicoelotes jiaohanyanensis sp. n. (male and female), Flexicoelotes jinlongyanensis sp. n. (male and female), Flexicoelotes pingzhaiensis sp. n. (female), Flexicoelotes xingwangensis sp. n. (male and female).     

Ginsenoside Rg1 protects H9c2 cells against nutritional stress-induced injury via aldolase /AMPK/PINK1 signalling

Insufficient nutrients supply will greatly affect the function of cardiac myocytes. The adaptive responses of cardiac myocytes to nutritional stress are not fully known. Ginsenoside Rg1 is one of the most pharmacologically active components in Panax Ginseng and possesses protective effects on cardiomyocyte. Here, we investigate the effects of ginsenoside Rg1 on H9c2 cells which were subjected to nutritional stress. Nutritional stress-induced by glucose deprivation strongly induced cell death and this response was inhibited by ginsenoside Rg1. Importantly, glucose deprivation decreased intracellular ATP levels and mitochondrial membrane potential. Ginsenoside Rg1 rescued ATP levels and mitochondrial membrane potential in nutrient-starved cells. For molecular mechanisms, ginsenoside Rg1 increased the expressions of PTEN-induced kinase 1 (PINK1) and p-AMPK in glucose deprivation treated H9c2 cells. Reducing the expression of aldolase in H9c2 cells inhibited ginsenoside Rg1′s actions on PINK1 and p-AMPK. Further, the nutritional stress mice were used to verify the mechanisms obtained in vitro. Ginsenoside Rg1 increased the expressions of aldolase, p-AMPK, and PINK1 in starved mice heart. Taken together, our results reveal that ginsenoside Rg1 limits nutritional stress-induced H9c2 cells injury by regulating the aldolase /AMP-activated protein kinase/PINK1 pathway.     

Advances in research on signal molecules regulating biofilms

World Journal of Microbiology and Biotechnology - Antibiotic and arsenic (As) contaminations are worldwide public health problems. Previously, the bacterial ABC-type efflux protein MacAB reportedly...     

Bayesian nonparametric inference for panel count data with an informative observation process

In this paper, the panel count data analysis for recurrent events is considered. Such analysis is useful for studying tumor or infection recurrences in both clinical trial and observational studies. A bivariate Gaussian Cox process model is proposed to jointly model the observation process and the recurrent event process. Bayesian nonparametric inference is proposed for simultaneously estimating regression parameters, bivariate frailty effects, and baseline intensity functions. Inference is done through Markov chain Monte Carlo, with fully developed computational techniques. Predictive inference is also discussed under the Bayesian setting. The proposed method is shown to be efficient via simulation studies. A clinical trial dataset on skin cancer patients is analyzed to illustrate the proposed approach.