FPGA-based Digital Baseband Transmission System Performance Tester Research and Design

Communication System Transmission Performance Tester, as a digital communication system design and testing equipment, plays an important role in the construction and daily maintenance of the communication system. The paper presents a kind of tester, which is designed using Cyclone IV FPGA (Field Programmable Gata Array) and VHDL (Very High Speed Integrated Circuits Hardware Description Language). According to the features in the eye diagram, the system performance can intuitively and qualitatively evaluated. The results prove that the system accurately displayed the eye diagram, thereby reflected the performance of the baseband transmission system truthfull

Oxygen is required for the l-cysteine-mediated decomposition of protein-bound dinitrosyl-iron complexes

Increasing evidence suggests that iron-sulfur proteins are the primary targets of nitric oxide (NO). Exposure of Escherichia coli cells to NO readily converts iron-sulfur proteins to protein-bound dinitrosyl-iron complexes (DNICs). Although the protein-bound DNICs are stable in vitro under aerobic or anaerobic conditions, they are efficiently repaired in aerobically growing E. coli cells even without new protein synthesis. The cellular repair mechanism for the NO-modified iron-sulfur proteins remains largely elusive. Here we report that, unlike aerobically growing E. coli cells, starved E. coli cells fail to reactivate the NO-modified iron-sulfur proteins. Significantly, the addition of l-cysteine, but not other related biological thiols, results in decomposition of the protein-bound DNICs in starved E. coli cells and in cell extracts under aerobic conditions. However, under anaerobic conditions, l-cysteine has little or no effect on the protein-bound DNICs in starved E. coli cells or in vitro, suggesting that oxygen is required for the l-cysteine-mediated decomposition of the protein-bound DNICs. Additional studies reveal that l-cysteine is able to release the DNIC from the protein and bind to it, and the l-cysteine-bound DNICs are rapidly disrupted by oxygen, resulting in the eventual decomposition of the protein-bound DNICs under aerobic conditions. © 2010 Elsevier Inc

Reactivity of nitric oxide with the [4Fe-4S] cluster of dihydroxyacid dehydratase from Escherichia coli

Although the NO (nitric oxide)-mediated modification of iron-sulfur proteins has been well-documented in bacteria and mammalian cells, specific reactivity of NO with iron-sulfur proteins still remains elusive. In the present study, we report the first kinetic characterization of the reaction between NO and iron-sulfur clusters in protein using the Escherichia coli IlvD (dihydroxyacid dehydratase) [4Fe-4S] cluster as an example. Combining a sensitive NO electrode with EPR (electron paramagnetic resonance) spectroscopy and an enzyme activity assay, we demonstrate that NO is rapidly consumed by the IlvD [4Fe-4S] cluster with the concomitant formation of the IlvD-bound DNIC (dinitrosyl-iron complex) and inactivation of the enzyme activity under anaerobic conditions. The rate constant for the initial reaction betweenNOand the IlvD [4Fe-4S] cluster is estimated to be (7.0±2.0)×106 M-2 · s-1 at 25°C, which is approx. 2-3 times faster than that of the NO autoxidation by O2 in aqueous solution. Addition of GSH failed to prevent the NOmediated modification of the IlvD [4Fe-4S] cluster regardless of the presence of O2 in the medium, further suggesting that NO is more reactivewith the IlvD [4Fe-4S] cluster than with GSH or O2. Purified aconitase B [4Fe-4S] cluster from E. coli has an almost identical NO reactivity as the IlvD [4Fe-4S] cluster. However, the reaction between NO and the endonuclease III [4Fe-4S] cluster is relatively slow, apparently because the [4Fe-4S] cluster in endonuclease III is less accessible to solvent than those in IlvD and aconitase B. When E. coli cells containing recombinant IlvD, aconitase B or endonuclease III are exposed to NO using the Silastic tubing NO delivery system under aerobic and anaerobic conditions, the [4Fe-4S] clusters in IlvD and aconitase B, but not in endonuclease III, are efficiently modified forming the proteinbound DNICs, confirming that NO has a higher reactivity with the [4Fe-4S] clusters in IlvD and aconitase B than with O2 or GSH. The results suggest that the iron-sulfur clusters in proteins such as IlvD and aconitase B may constitute the primary targets of the NO cytotoxicity under both aerobic and anaerobic conditions. © The Authors Journal compilation © 2009 Biochemical Society

L\'evy Noise-Induced Stochastic Resonance in a Bistable System

Stochastic resonance phenomenon induced by non-Gaussian L\'evy noise in a second-order bistable system is investigated. The signal-noise-ratio for different parameters is computed by an efficient numerical scheme. The influences of the noise intensity, stability index of L\'evy noise and amplitude of external signal on the occurrence of stochastic resonance phenomenon are characterized. This implies that a high amplitude of signal not only enhances the output power spectrum of system but also promotes stochastic resonance, and a proper adjustment of L\'evy noise intensity in a certain range enlarges the peak value of output power spectrum which is significant for stochastic resonance. Moreover, with the optimal damping parameter, lowering the stability index leads to larger fluctuations of L\'evy noise, and further reduces the chance of the stochastic resonance

The Extra Domain A of Fibronectin Increases VEGF-C Expression in Colorectal Carcinoma Involving the PI3K/AKT Signaling Pathway

The extra domain A (EDA)-containing fibronectin (EDA-FN), an alternatively spliced form of the extracellular matrix protein fibronectin, is predominantly expressed in various malignancies but not in normal tissues. In the present study, we investigated the potential pro-lymphangiogenesis effects of extra domain A (EDA)-mediated vascular endothelial growth factor-C (VEGF-C) secretion in colorectal carcinoma (CRC). We detected the expressions of EDA and VEGF-C in 52 human colorectal tumor tissues and their surrounding mucosae by immunohistochemical analysis, and further tested the correlation between the expressions of these two proteins in aforementioned CRC tissues. Both EDA and VEGF-C were abundantly expressed in the specimens of human CRC tissues. And VEGF-C was associated with increased expression of EDA in human CRC according to linear regression analysis. Besides, EDA expression was significantly correlated with lymph node metastasis, tumor differentiation and clinical stage by clinicopathological analysis of tissue microarrays containing tumor tissues of 115 CRC patients. Then, human CRC cell SW480 was transfected with lentivectors to elicit expression of shRNA against EDA (shRNA-EDA), and SW620 was transfected with a lentiviral vector to overexpress EDA (pGC-FU-EDA), respectively. We confirmed that VEGF-C was upregulated in EDA-overexpressed cells, and downregulated in shRNA-EDA cells. Moreover, a PI3K-dependent signaling pathway was found to be involved in EDA-mediated VEGF-C secretion. The in vivo result demonstrated that EDA could promote tumor growth and tumor-induced lymphangiogenesis in mouse xenograft models. Our findings provide evidence that EDA could play a role in tumor-induced lymphangiogenesis via upregulating autocrine secretion of VEGF-C in colorectal cancer, which is associated with the PI3K/Akt-dependent pathway

Analysis of the Spatial and Temporal Evolution of Energy-Related CO₂ Emissions in China’s Coastal Areas and the Drivers of Industrial Enterprises above Designated Size—The Case of 82 Cities

The energy consumption by industrial enterprises above designated size in China’s coastal region is the main source of CO2 emissions. This study analyzes the spatial and temporal evolution patterns and driving factors of CO2 emissions due to the energy consumption by industrial enterprises above designated size. Enterprises in 82 cities in China’s coastal regions were studied from 2005 to 2020 based on their CO2 emissions and socio-economic data. The Exploring Spatial Data Analysis (ESDA) methodology and Logarithmic mean Divisia Index decomposition (LMDI model) were used. The results show that, during the study period, energy-related CO2 emissions from industrial enterprises above designated size in China’s coastal areas generally show a fluctuating upward trend. However, a few cities showed a trend from steady growth to a peak and then a slow decline, which may realize the “double carbon” target in advance. The spatial correlation of CO2 emission intensity showed a decreasing and then increasing trend, and there were spatial aggregation characteristics in some cities. Among the driving factors, the pull effect is higher than the inhibition effect; the output scale contributes the most to the pull effect, and labor productivity contributes the most to the inhibition effect. The results of this study have a certain reference value for the realization of the “double carbon” target in China’s coastal regions