Based on the principle of dynamic equivalence, a new dynamic model of compliant mechanisms is developed using the pseudo-rigid-body model. The dynamic equation of general planar compliant mechanisms is derived. The natural frequency of a compliant mechanism is obtained in the example of a planar compliant parallel-guiding mechanism. The numerical results show the effectiveness and advantage of the proposed method compared with the methods of FEA and flexible mechanisms.

Objective: To determine the role of microRNA 21(miR-21) on left ventricular remodeling of rat heart with ischemia-reperfusion (I/R) injury and to investigate the underlying mechanism of miR-21 mediated myocardium protection.Methods: Rats were randomly divided into three groups: an I/R model group with Ad-GFP (Ad-GFP group), an I/R model group with Ad-miR-21 (Ad-miR-21 group) and a sham-surgery group. Changes in hemodynamic parameters were recorded at 1 week after I/R. Histological diagnosis was achieved by hematoxylin and eosin (H&E). Left ventricular (LV) dimensions, myocardial infarct size, LV/BW, collagen type Ⅰ, type Ⅲ and PCNA positive cells were measured. Primary cultures of neonatal rat cardiac ventricular myocytes were performed and cell ischemic injury was induced by hypoxia in a serum- and glucose-free medium, and reoxygenation (H/R).MiR-21 inhibitor and pre-miR-21 were respectively added to the culture medium for the miR-21 knockdown and for the miR-21 up-regulation. qRT-PCR was used to determine the miR-21 levels in cultured cells. Flow cytometry was performed to examine the cell apoptosis.Results: In the Ad-miR-21 group, LV dimensions, myocardial infarct size, LV/BW, collagen type Ⅰ, type Ⅲ and PCNA positive cells all significantly decreased compared with the Ad-GFP group. At 1 week after I/R, the Ad-miR-21 significantly improved LVSP, LV +dp/dtmax, LV − dp/dtmin, and decreased heart rate (HR) and LVEDP compared with the Ad-GFP group. Compared with the Ad-GFP, the cell apoptotic rate significantly decreased in the Ad-miR-21 group. The miR-21 inhibitor exacerbated cardiac myocyte apoptosis and the pre-miR-21 decreased hypoxia/reoxygenation- induced cardiac myocyte apoptosis.Conclusions: Ad-miR-21 improves LV remodeling and decreases the apoptosis of myocardial cells, suggesting the possible mechanism by which Ad-miR-21 functions in protecting against I/R injury.

SummaryThere have been significant interests and efforts in the field of impedance control on robotic manipulation over last decades. Impedance control aims to achieve the desired mechanical interaction between the robotic equipment and its environment. This paper gives the overview and comparison of basic concepts and principles, implementation strategies, crucial techniques, and practical applications concerning the impedance control of robotic manipulation. This work attempts to serve as a tutorial to people outside the field and to promote discussion of a unified vision of impedance control within the field of robotic manipulation. The goal is to help readers quickly get into the problems of their interests related to impedance control of robotic manipulation and to provide guidance and insights in finding appropriate strategies and solutions.

SummaryThe aims of the present study were to determine the role of miR-214 on left ventricular remodeling of rat heart with acute myocardial infarction (AMI) and to further investigate the underlying mechanism of miR-214-mediated myocardial protection. AMI was induced in which adenovirus-expressing miR-214 (Ad-miR-214), anti-miR-214, or Ad-GFP had been delivered into rats hearts 4 days prior, while a phosphatase and tensin homolog (PTEN) inhibitor was administered via intra-peritoneal injection 30 minutes prior to AMI. Changes in hemodynamic parameters were detected and recorded. Left ventricular (LV) dimensions and LV/BW were measured. Quantitative RT-PCR was used to determine the miR-214 expression levels of the myocytes in the infarcted, border, and non-infarcted areas of the LV. Myocardial infarct size was also measured. Flow cytometry analysis was performed to examine cellular apoptosis. Western blot analysis was performed to examine PTEN expression. The results showed that miR-214 was upregulated in both border and infarcted areas. Myocardial cell apoptosis was decreased in the Ad-miR-214 group, but was increased in the anti-miR-214 group, while there were no differences among the Ad-GFP-group, PTEN-ad-miR-214 group, or PTEN-anti-miR-214 group. Myocardial infarct size, LV dimensions, heart rate (HR), and LV end-diastolic pressure (LVEDP) were decreased while the maximal rates of rise or decline in blood pressure in the ventricular chamber (± dp/dt) and LV systolic pressure (LVSP) were increased in the Ad-miR-214 group, all of which exhibited opposite changes in the anti-miR-214 group. PTEN was downregulated in the Ad-miR-214 group and upregulated in the anti-miR-214 group. PTEN was decreased in both the border and infarcted areas compared with non-infarcted areas. The study results suggest that Ad-miR-214 improves LV remodeling and decreases the apoptosis of myocardial cells through PTEN, suggesting a possible mechanism by which Ad-miR-214 functions in protecting against AMI injury. (Int Heart J 2016; 57: 247-250) Key words: Adenovirus expressing transfer, QRT-PCR analysis, Western blot analysis, Rat acute myocardial model C ardiovascular diseases constitute the major leading cause of death globally, and current estimates indicate that as many as 1 in 6 deaths per year can be attributed to coronary disease and associated myocardial ischemia in the United States.1) Cardiac remodeling after acute myocardial infraction (AMI) results in poor cardiac performance, which often leads to heart failure.2) Myocardial fibrosis results in mechanical stiffness, which contributes to ventricular contractile dysfunction. 3)MicroRNAs (miRNAs, miRs) are a class of endogenous, small (~22 nt) non-coding single-stranded RNAs, which have highly conserved sequences among species.4) Approximately 1,400 miRNAs have been identified thus far in humans, and this number is growing.5) An individual miRNA is as important as a transcription factor due to its ability to regulate the expression of multiple target genes.5) The majority of ce...

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