Search

In view of the digital geophone self-test system application demand for a variety of high quality waveform signal. This paper introduces a kind of design method of direct digital synthesis waveform signal generator based on FPGA. It mainly discusses the principle of the method of frequency synthesis technology, design thinking and implementation method. And using the design method of pipeline structure to improve circuit structure of 48 bits phase accumulator, so as to improve the running speed, and further increase the resolution of frequency synthesis. The test shows that the signal generator can produce sine wave, square wave, sawtooth wave, triangle wave. The frequency resolution can reach 0.18μHz. The highest output frequency is up to 20MHz, and frequency switch time is 20ns.

In this article, a design method of asynchronous FIFO memory based on FPGA is put forward. With FPGA as the core controller, We adopt Verilog HDL and top-down design method to build a top-level module design and also analyze the mark logic of asynchronous FIFO and the elimination of semi-stable state under Quartus II development platform. Besides, with the application of Gray code conversion technology, not only the reliable transmission of data is guaranteed but also design efficiency is improved. Through contrast experiment analysis and simulation test, the validity and reliability of asynchronous FIFO memory are verified, meeting the basic requirement that FIFO can hold more enough data without spillovers despite the fullness of data.

According to the requirements of general surgical operation, we designed the plasma therapy system which took the microprocessor as the control core based on medical low temperature plasma technology. Making use of High-frequency AC electric field exciting ions in the electrolyte can generate low temperature plasma. Conclusion: the low-temperature plasma therapy system can significantly reduce blood loss and length of incision, shorten operating time, and postoperative complications in general surgical operation.

Both maximum entropy method and Particle swarm optimization (PSO) are common threshold segmentation methods which have been used not only in image segmentation, but also in multi-threshold segmentation. Maximum entropy method is time-consuming, PSO may easily get trapped in a local optimum. In view of this concerning issue, we propose the PSO and maximum entropy are combined to make improvements on the PSO introduced in expansion model and opposition-based module. The objective functions of the maximum entropy as well as the PSO are obtained, which have improved to optimize them and search the optimal threshold combination, to achieve multi-threshold image segmentation. The results demonstrate that the new algorithm improved the segmentation speed and enhanced the robustness. And the optimizing results are stable.

Although neural stem cell (NSC) transplantation is widely expected to become a therapy for nervous system degenerative diseases and injuries, the low neuronal differentiation rate of NSCs transplanted into the inner ear is a major obstacle for the successful treatment of spiral ganglion neuron (SGN) degeneration. In this study, we validated whether the local microenvironment influences the neuronal differentiation of transplanted NSCs in the inner ear. Using a rat SGN degeneration model, we demonstrated that transplanted NSCs were more likely to differentiate into microtubule-associated protein 2 (MAP2)-positive neurons in SGN-degenerated cochleae than in control cochleae. Using real-time quantitative PCR and an immunofluorescence assay, we also proved that the expression of Wnt1 (a ligand of Wnt signaling) increases significantly in Schwann cells in the SGN-degenerated cochlea. We further verified that NSC cultures express receptors and signaling components for Wnts. Based on these expression patterns, we hypothesized that Schwann cell-derived Wnt1 and Wnt signaling might be involved in the regulation of the neuronal differentiation of transplanted NSCs. We verified our hypothesis in vitro using a coculture system. We transduced a lentiviral vector expressing Wnt1 into cochlear Schwann cell cultures and cocultured them with NSC cultures. The coculture with Wnt1-expressing Schwann cells resulted in a significant increase in the percentage of NSCs that differentiated into MAP2-positive neurons, whereas this differentiation-enhancing effect was prevented by Dkk1 (an inhibitor of the Wnt signaling pathway). These results suggested that Wnt1 derived from cochlear Schwann cells enhanced the neuronal differentiation of transplanted NSCs through Wnt signaling pathway activation. Alterations of the microenvironment deserve detailed investigation because they may help us to conceive effective strategies to overcome the barrier of the low differentiation rate of transplanted NSCs.

In this article, a design of multi-channel data acquisition system is presented. With FPGA as the core controller, the system can implement logic control over the high-speed ADC and acquire high-speed and high-resolution sample data. Using asynchronous FIFO as a cache, it can transfer data between two different clock domains: ADC data acquisition module and RS485 data module, which helps to improve the work efficiency and data throughput of the system. In the Quartus II development platform, Verilog hardware description language is adopted and finite state machine so that parallel acquisition operation to multi-channel ADC controlled by FPGA can be achieved and the system can become equipped with high-resolution, strong real-timeliness, low noise interference and other advantages. When it comes to the final step, simulation of AD sampling, asynchronous FIFO and RS485 transmission are conducted under the Modelsim environment and on-line testing by Signaltap to the system is synchronously implemented. The validity and reliability of the system are verified.

To improve the accuracy and robustness of the moving object detection in the image sequence, the author improves the traditional algorithm which is based on the gray-value difference. The author makes good use of the color information of images and applies the pixels in red, green, blue the three component value as its identifying information. According to the background image color composition, it adapts and adjusts the proportion of the three groups. Dynamic threshold is used to do the binarization separation of the background difference image. The simulation experiment shows, this algorithm makes full use of the color features of image and achieve the expected goal of high recognizability and good robustness.

Objective Cochlear progenitor cells could be used to explore the cochlea developmental mechanism and for cell replacement therapy in deafness. MicroRNAs are small, noncoding RNAs that could regulate the cell fate of stem cells, as well as cellular proliferation, differentiation and maturation. An expression profile analysis of microRNAs is necessary to understand their complex roles in differentiating cochlear progenitor cells. Methods The microRNAs microarray was used to analyze microRNA expression changes while differentiating cochlear progenitor cells. Quantitative real-time polymerase chain reaction was used to confirm and compare the results of the microarray and to detect the expression pattern of several microRNAs during the differentiation of neural stem cells. Results Nearly 100 microRNAs were identified from the microarray. Most showed changes in expression levels as cochlear progenitor cell differentiation progressed. The quantitative real-time polymerase chain reaction result demonstrated that the miR-183 family exhibits cell-specific expression in cochlear progenitor cells compared with neural stem cells. Conclusions The temporal regulation of these microRNAs indicated that they might play different roles in differentiating cochlear progenitor cells, and that specific microRNAs might influence the cell fate determination of cochlear progenitor cells.

A lipase gene from Serratia marcescens ECU1010 was cloned into expression vector pET28a, sequenced, and overexpressed as an N terminus His-tag fusion protein in Escherichia coli. Through the optimization of culture conditions in shake flask, the lipase activity was improved up to 1.09 x 10⁵ U/l, which is a great improvement compared to our previous reports. It was purified to homogeneity by Ni-NTA affinity chromatography with an overall yield of 59.4% and a purification factor of 2.4-fold. This recombinant lipase displayed excellent stability below 30 °C and within the pH range of 5.0-6.8, giving temperature and pH optima at 40 °C and pH 9.0, respectively. The lipase activity was found to increase in the presence of metal ions such as Ca²+, Cu²+, and some nonionic surfactants such as PEG series. In addition, among p-nitrophenyl esters of fatty acids with varied chain length, the recombinant lipase showed the maximum activity on p-nitrophenyl laurate (C₁₂). Using racemic trans-3-(4'-methoxy-phenyl)-glycidyl methyl ester [(±)-MPGM] as substrate, which is a key chiral synthon for production of diltiazem, a 50% conversion yield was achieved after 4 h in toluene-water (100 mM KPB phosphate buffer, pH 7.5) biphasic system (5:5 ml) at 30 °C under shaking condition (160 rpm), affording (-)-MPGM in nearly 100% ee. The K(m) and V(max) values of the lipase for (±)-MPGM were 222 mM and 1.24 mmol min⁻¹ mg⁻¹, respectively. The above-mentioned features make the highly enantioselective lipase from Serratia marcescens ECU1010 a robust biocatalyst for practical use in large-scale production of diltiazem intermediate.

Many studies have suggested that VSMC (vascular smooth muscle cell) apoptosis plays a key role in destabilization and rupture of atherosclerotic plaques. Therefore protection for VSMCs from apoptosis is a promising approach to stabilize 'vulnerable' lesions. However, the mechanisms as to why VSMCs in the fibrous cap often appear as profilerated in early stages, but turn apoptotic in advanced stages, are still unknown. In the present study, using RNAi (RNA interference) technology and a CaN (calcineurin) antagonist, the correlation between CaN and RANTES (regulated upon activation, normal T-cell expressed and secreted) in cultured rat apoptotic VSMCs stimulated by IFNgamma (interferon gamma; 20 ng/ml) and CD40L (CD40 ligand; 100 ng/ml) was investigated. RANTES released from VSMCs in each group was measured by ELISA and its mRNA in VSMCs was determined by RT (reverse transcription)-PCR. The total activity and expression of CaN in VSMCs were detected by the zymochemistry method and Western blot analysis respectively. From the results of the present study it can be hypothesized that an elevated CaN concentration in endochylema, by the CD40-CD40L signal pathway, induces VSMC apoptosis accomplished by the overexpression of RANTES. Therefore RANTES is a potential target for treating vulnerable atherosclerotic plaques owing to its crucial downstream regulating role in CaN-dependent VSMC apoptosis.

Pioglitazone, used clinically in the treatment of type 2 diabetes mellitus, has been implicated as a regulator of cellular inflammatory and ischemic responses. The present study examined whether pioglitazone could inhibit cardiomyocyte apoptosis and reduce mitochondrial ultrastructure injury and membrane potential loss in the ischemic/reperfused heart of the rat. Furthermore, we investigated whether the protective effect of pioglitazone was related to opening of the mitochondrialATP-sensitive potassium channels.Adult male Sprague-Dawley rats were subjected to 30 min of ischemia followed by 4 h of reperfusion. At 24 h before ischemia, rats were randomized to receive 0.9% saline, 5-hydroxydecanoate (5-HD, 10 mg kg(-1), i.v.) plus pioglitazone (3 mg kg(-1), i.v.) or pioglitazone (3 mg kg(-1), i.v.). One group served as sham control. We investigated mitochondrial structure, apoptosis rate and Bcl-2, Bax and Caspase-3 proteins by immunohistochemistry staining. RT-PCR was used to determine the expression of P38MAPKmRNA and JNKmRNA. Western blotting was used to measure the expression of P38MAPK, JNK and NFkappaB P65. A second group of rats were randomly divided into sham-operated, ischemia/reperfusion (I/R), pioglitazone treatment, 5-HD + pioglitazone and 5-HD groups and the size of myocardial infarction was determined. Primary cultured cardiomyocytes of neonatal Sprague-Dawley rats were divided into control, hypoxia reoxygenation, different concentrations of pioglitazone and 5-HD + pioglitazone groups. JC-1 staining flowcytometry was used to examine mitochondrial membrane potential (DeltaPsim).Pioglitazone decreased mitochondrial ultrastructural damage compared to I/R, and reduced infarct size from 34.93 +/- 5.55% (I/R) to 20.24 +/- 3.93% (P0.05). Compared with the I/R group, the apoptosis rate and positive cell index (PCI) of Bax and Caspase-3 proteins in the pioglitazone group were significantly decreased (P0.05), while the PCI of Bcl-2 protein was increased (P0.05). There was no significant difference between the I/R and 5-HD + pioglitazone groups. Compared with the sham-operated group, the expression of P38MAPK mRNA, JNK mRNA and protein of P38MAPK, JNK and NFkappaB P65 in I/R was increased (P0.05). Pioglitazone did inhibit the increase in expressions vs I/R (P0.05). The rate of loss DeltaPsim cells in the pioglitazone group was significantly lower than in the hypoxia reoxygenation group, while the addition of 5-HD inhibited the effect of pioglitazone.Pioglitazone inhibited cardiomyocyte apoptosis and reduced mitochondrial ultrastructure injury and membrane potential loss in the ischemic/reperfused heart of rat. These protective effects of pioglitazone may be related to opening mitochondrial(ATP)-sensitive potassium channels.

A theoretical model is proposed in order to study the configuration resonance in s-SNOM. The electromagnetic coupling between the sample and the probe tip is described with the quasi-electrostatic field theory. This method permits us to analyze the configurational resonance evoked by the interaction between the probe tip and the sample in s-SNOM intuitively. The resonant conditions for a certain system are presented in an explicit form. On the condition of considering the actual size of the sample dipoles and the probe dipole, we discuss the possibility of realizing the configurational resonance for various material samples. The numerical results indicate that the polarizability of the dielectric probe tip is too small to arouse this resonance, whereas, with the surface plasmon resonance emerging on the metallic nanoparticles, the enhanced polarizability of the metallic probe tip ensures the requirements of fulfilling the resonance.

Regulatory T-cells (Tregs) are generally regarded as key immunomodulators that maintain immune tolerance and counteract tissue damage in a variety of immune-mediated disorders. However, its role in myocardial ischaemia/reperfusion injury (MIRI) remains unknown. The purpose of the present study was to determine whether Tregs exert a beneficial effect on mouse MIRI. We examined the role of Tregs in murine MIRI by depletion using 'depletion of regulatory T-cell' (DEREG) mice and adoptive transfer using Forkhead box P3 (Foxp3)-GFP knockin mice and the mechanisms of cardio protection were further studied in vivo and in vitro. Tregs rapidly accumulated in murine hearts following MIRI. Selective depletion of Tregs in the DEREG mouse model resulted in aggravated MIRI. In contrast, the adoptive transfer of in vitro-activated Tregs suppressed MIRI, whereas freshly isolated Tregs had no effect. Mechanistically, activated Treg-mediated protection against MIRI was not abrogated by interleukin (IL)-10 or transforming growth factor (TGF)-β1 inhibition but was impaired by the genetic deletion of cluster of differentiation 39 (CD39). Moreover, adoptive transfer of in vitro-activated Tregs attenuated cardiomyocyte apoptosis, activated a pro-survival pathway involving Akt and extracellular-signal-regulated kinase (ERK) and inhibited neutrophil infiltration, which was compromised by CD39 deficiency. Finally, the peripheral blood mononuclear cells of acute myocardial infarction (AMI) patients after primary percutaneous coronary intervention (PCI) revealed a decrease in CD4+CD25+CD127low Tregs and a relative increase in CD39+ cells within the Treg population. In conclusion, our data validated a protective role for Tregs in MIRI. Moreover, in vitro-activated Tregs ameliorated MIRI via a CD39-dependent mechanism, representing a putative therapeutic strategy.

To clarify the intestinal barrier function (IBF) state of patients with acute myocardial infarction-heart failure (AMI-HF), and to compare the therapeutic effects of rhubarb and Pantoprazole (proton pump inhibitor).Enrolled were 107 AMI patients from ICU, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from May 2008 to April 2010. Of them, 47 AMI patients without HF were recruited as the control group, while 60 AMI-HF patients were randomly assigned to the rhubarb group (30 cases, treated by rhubarb + Pantoprazole) or the Pantoprazole group (30 cases, treated by Pantoprazole + routine treatment). All patients were treated till the 14th day of the onset. The fecal occult blood (FOB) test was performed daily. The occurrence of the digestive tract hemorrhage on the 14th day after onset was compared. The N-terminal pro-brain natriuretic peptide (NT-proBNP), serum D-lactic acid, plasma glutamine (Gln), endotoxin and cytokines [high sensitive C reaction protein (hsCRP), tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10)], and heart function were compared among the three groups before and after treatment.There was no statistical difference in the case number of using aspirin, clopidogel, low molecular weight heparin, ACEI/ARB, statins, insulin, and antibiotics among the 3 groups. The case number of using beta-blocker was obviously lower in the two medication groups than in the control group (P0.05). The case number of using diuretics was obviously higher in the two medication groups than in the control group (P0.05). There was no statistical difference in the incidence of digestive tract hemorrhage (P = 0.413). Compared with the control group before treatment, Gln and ejection fraction (EF) were both lowered, NT-proBNP, D-lactic acid, endotoxin, hsCRP, TNF-alpha, and IL-10 increased in the two medication groups (P0.01). There was no statistical difference in each index between the two medication groups (P0.05). Compared with before treatment, NT-proBNP, D-lactic acid, endotoxin, hsCRP, TNF-alpha, and IL-10 decreased in the Pantoprazole group (P0.01), and no obvious change in Gin or EF was found (P0.05). Gin and EF increased in the rhubarb group after treatment, and they were higher than those of the control group. Blood NT-proBNP, D-lactic acid, endotoxin, hsCRP, TNF-alpha, and IL-10 decreased in the rhubarb group after treatment, showing statistical difference when compared with the control group (P0.01, P0.05).Impaired IBF and endotoxemia existed in AMI-HF patients. Rhubarb not only could prevent the digestive tract hemorrhage, but also could reduce endotoxemia, inhibit inflammatory reactions, and improve the heart function through ameliorating the IBF.

Path planning is an important technique to realize robot navigation. In this paper, through using Bezier curves, it is transfermed into an optimization problem. An improved dynamic multi-swarm particle swarm optimizer with cross operator is proposed to do this task. Through a set of experiments on four predefined path planning problems, the proposed algorithm proves its effectiveness on this kind of problems.

To study the mechanism of the therapeutic angiogenesis effect of bone marrow stromal cells (BMSCs) implantation on rat acute myocardial infarction models.The rat acute myocardial infarction models were made by coronary artery ligation and divided into 2 groups at random. In the experiment group, twice passaged BMSCs were labeled with BrdU and then implanted into the infarction region of the recipients in 4 weeks. The control group was the model rats received only DMEM injection. In control group, the hearts were harvested on the day 3, 7, 14, 28, 42 and 56. The infarction regions were examined to identify the angiogenesis and the expression of the VEGF and bFGF. In experiment group, the hearts were examined on the day 42 and 56 after AMI (the day 14 and 28 after cells implantation).Viable cells labeled with BrdU could be identified in host hearts. Histologic examination found most donor cells within the infarction region expressed fibroblastic and endothelial phenotype. The transplantation regions had a greater capillary density than the control regions did (14 +/- 4.7/HPF vs 6 +/- 2.4/HPF, P0.05). In the control group, the expression of VEGF and bFGF within the infarction regions peaked on day 7, and then decreased over time. In the experiment groups, the expression of bFGF and VEGF on the day 42 and 56 had a higher level than the control group did.The expression of VEGF and bFGF is significantly increased after cells therapy during the late phase of AMI. It indicates that BMSCs implantation promoted the angiogenesis is mediated by its differentiation into endothelium and the increased release of VEGF and bFGF.

The study was purposed to investigate the immune regulatory effects of human bone marrow mesenchymal stem cells (hMSCs) on Foxp3 expressing CD4(+)CD25(+) regulatory T cells and to explore the mechanism of immune modulation by hMSCs. Human MSCs were isolated and expanded from bone marrow cells, and identified with cell morphology, and the phenotypes were assessed by immunohistochemistry. Human peripheral blood mononuclear cells (hPBMNCs) were prepared by centrifugation on a Ficoll Hypaque density gradient. The hMSCs (1 x 10(3), 1 x 10(4), 1 x 10(5)) were added into wells containing hPBMNCs (1 x 10(6)) from an unrelated donor in the presence of rhIL-2. After 5 days of co-culture, the percentage of CD4(+)CD25(+) T cells was detected by flow cytometry. T cell proliferation was assessed by [(3)H] thymidine incorporation using a liquid scintillation counter. The expression of Foxp3 in CD4(+)CD25(+) T cells was detected by reverse transcription polymerase chain reaction (RT-PCR). Cytokines (TGF-beta, IL-12, IFN-gamma, IL-10) concertrations of cultured supernatants were measured with ELISA. The results indicated that in all the experiments, the presence of hMSCs with hPBMNCs resulted in a statistically significant decrease in T cell proliferation, in dose-dependent manner. The increase of percentage of CD4(+)CD25(+) T cells in the peripheral CD4(+) T cell was observed after coculturing lymphocytes with hMSCs (p0.01). The expression of Foxp3-mRNA (Foxp3/beta-actin) in hMSCs groups was significantly higher than that in the control and was negatively associated with the value of CPM representing T proliferation. The levels of TGF-beta and IL-10 were higher in hMSCs groups than that in the control, and the levels of TGF-beta and IL-10 correlated positively with Foxp3-mRNA expression and the percentage of CD4(+)CD25(+) T cells. However, the secretion of IL-12 and IFN-gamma was significantly attenuated by hMSCs coculture, and there was no correlation with Foxp3-mRNA expression and the percentage of CD4(+)CD25(+) T cells. It is concluded that the Foxp3 expressing regulatory T cells may play an important role in the immune regulatory by hMSCs. Its mechanism is related to that the hMSCs-mediated TGF-beta and IL-10 convert CD4(+)CD25(-) T cells into CD4(+)CD25(+) T regulatory T cells, which specifically inhibits the proliferation of T cells.