In real traffic,any vehicle must give lane-changing signal(i.e.the turn signal) before changing lanes;at this time,the vehicles behind the lane-changing vehicle will be hindered and may form "plugs" due to t...In real traffic,any vehicle must give lane-changing signal(i.e.the turn signal) before changing lanes;at this time,the vehicles behind the lane-changing vehicle will be hindered and may form "plugs" due to the turn signal effect.However,few studies focus on exploring the effect.In this paper,the turn signal effect was taken into account by proposing a new symmetric two-lane cellular automaton(T-STCA) model,and the new model was set to compare with the STCA,H-STCA and A-STCA models.Numerical results show that using the T-STCA model to describe lane-changing or overtaking,the process appeared in several consecutive time steps;while using the other three models,the process appeared only in one time step.In addition,the T-STCA model could describe the mixed traffic flow more realistically and the turn signal effect could help the plugs to dissolve more quickly.展开更多
Supply chain partnerships are an essential component of business innovations.This study uses data on A-share listed companies on the Shanghai and Shenzhen stock exchanges from 2012 to 2022 to conduct a multi-period di...Supply chain partnerships are an essential component of business innovations.This study uses data on A-share listed companies on the Shanghai and Shenzhen stock exchanges from 2012 to 2022 to conduct a multi-period difference-in-differences analysis based on a list of green supply chain management(GSM)companies.We find that GSM significantly promotes low-carbon technology innovations(LCT)of upstream enterprises.The mechanism analysis indicates that GSM has a resource effect and signal effect that generate LCT spillovers.In terms of the resource effect,GSM companies offer green credit and support green procurement,thereby providing financial support for green investments in upstream LCT.In terms of a signaling effect,GSM strengthens the effectiveness of institutional investors,the public,and online media in supervising upstream suppliers’green credentials,thereby promoting upstream LCT.A heterogeneity analysis shows that when midstream companies are state-owned enterprises or industry leaders,and when the concentration and stability of supply chain purchase relationships are higher,the LCT spillover effects of GSM are more pronounced.Further analysis reveals that GSM has bidirectional horizontal spillover effects and that upstream unidirectional vertical spillover effects are limited to first-level suppliers.Additionally,under the premise of not compromising economic benefits and stability,GSM shows an emerging trend of transitioning from environmentally compliant“light green”supply chains to“deep green”supply chains focused on pollution reduction,carbon reduction,and energy conservation.展开更多
Objective: To investigate the autophagy-inducing effect of Compound Berberine (CBBR) on CNE2 nasopharyngeal carcinoma (NPC) cells and its possible targets in P13K/AKT/mTOR signaling pathway. Methods: CNE2 cells at exp...Objective: To investigate the autophagy-inducing effect of Compound Berberine (CBBR) on CNE2 nasopharyngeal carcinoma (NPC) cells and its possible targets in P13K/AKT/mTOR signaling pathway. Methods: CNE2 cells at exponential growth phase were taken as the target cells in this study. Firstly, IC50 concentration for CBBR was determined by MTT assay. Then, 3 different concentrations of CBBR, 0.25 mg⋅mL−1, 0.50 mg⋅mL−1 and 1.00 mg⋅mL−1, around the concentration of IC50, were taken for followed intervention experiments respectively. Fluorescein labeling method was utilized to assay the inducing effect of CBBR on the autophagic activity of CNE2 cells, followed by Western blot procedure to explore the changes of key messenger molecules in the autophagy-related signaling pathway of P13K/AKT/mTOR, both combined with 3-MA block test in a comparative way and carried out by detecting the expressive levels of Beclin 1, LC3-II and LC3-I as well as the ratio of LC3-II:LC3-I. Results: IC50 of CBBR was determined at the level of 0.5 mg⋅mL−1. The inducing effect of CBBR on autophagy of CNE2 cells was shown occurring in various modes, not a simple concentration-dependent tendency, with its effect minimal at the concentration of 0.25 mg⋅mL−1 and maximal at the concentration of 0.50 mg⋅mL−1, while only slightly higher at the concentration of 1.00 mg⋅mL−1 than that of 0.5 mg⋅mL−1. Although its inducing effect was weakened a little following the pretreatment by 3-MA, the effect combined with CBBR was still significantly higher than that of simply blocked by 3-MA. Moreover, changes in the expressive levels of Beclin1, LC3-II and LC3-I as well as LC3-II:LC3-I all showed a tendency corresponding to the changed autophagic features of CNE2 cells (P Conclusions: CBBR can bring about inhibiting effect on the proliferating activity of CNE2 cells through inducing increased autophagic activity via intervening targets in P13K/AKT/mTOR signaling pathway, and this effect could not be completely blocked by the antagonist 3-MA.展开更多
The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small syste...The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small system parameters. An analogue circuit was designed to perform the effect. The effect of signal modulating noise was shown in the analog simulation experiment. The analog experiment was conducted for two sinusoidal signals with different frequencies. The results show that there are a sinusoidal component corresponding to the input sinusoidal signal and a noise component presented as a Wiener process corresponding to the input white noise in the system output. By properly selecting system parameters, the effect of signal modulating noise can be manifested in the system output.展开更多
The effect of signal sampling depth in SIMS on profile was not reported We have found that the maximum sampling depth in SIMS is considerably bigger than the mean penetration range of primary ions and can skew the pro...The effect of signal sampling depth in SIMS on profile was not reported We have found that the maximum sampling depth in SIMS is considerably bigger than the mean penetration range of primary ions and can skew the profile of secondary ion counts for implanted samples on the more deeper direction from the surface. The effect of maximum sampling depth is true not only for implanted samples but also for the samples in the middle of which there is an other impurity-rich layer. The action principle of signal sampling depth effect and the method of decreasing the error produced by the effect are discussed in this展开更多
BACKGROUND: Signal regulatory protein alpha1 (Sirpα1) is a negative regulatory factor, and inhibits receptor tyro- sine kinase-dependent cell proliferating signal. This study was undertaken to observe the effect of s...BACKGROUND: Signal regulatory protein alpha1 (Sirpα1) is a negative regulatory factor, and inhibits receptor tyro- sine kinase-dependent cell proliferating signal. This study was undertaken to observe the effect of signal regulatory proteinα1 ( Sirpα1) on gankyrin, cyclin D1, CDK4 and Fas expression in Sk-hep1 mouse hepatoma carcinoma cell line. METHODS: BOSC 23 packed cells were respectively trans- fected by means of recombinated retrovirus including pLX- SN, pLXSN-Sirpα1 and pLXSN-Sirpα1Δ4Y2 with lipofec- tin, and various plasmid virus media (viral titer 2.1 × 106 CFU/ml) were collected and infected respectively in 80% confluent Sk-hepl cells. Transfected Sk-hep1 cells were se- lectively screened with G418 (1200 μg/ml), and Sk-hep1 cell lines transfected with various plasmids were obtained. The protein expressions of gankyrin, cyclin D1, CDK4 and Fas in various Sk-hep1 lines were determined by Western blotting. Various Sk-hep1 lines were recovered to culture with 10% fetal bovine serum at 12 hours and 24 hours after starving culture with free serum for 72 hours, and cells were collected to determine the percentage of S phase cells of proliferating cycle by flow cytometry. RESULTS: Sirpα1 transfection remarkably downregulated gankyrin and cyclin D1 expression. Sirpα1Δ4Y2 downregu- lation of gankyrin expression was greater than that of Sirpα1(P <0.05), but no significant effect of Sirpα1 and Sirpα1Δ4Y2 on CDK4 and Fas protein expression was ob- served in transfected Sk-hep1 lines (P >0.05). The per- centage of S phase cells significantly decreased in Sk-hep1 cells transfected with Sirpα1 and Sirpα1Δ4Y2 plasmids (vs pLXSN Sk-hep1, P <0.05). The percentage of S phase cells in various Sk-hep1 cells increased when recovering to culture with 10% fetal bovine serum at 12 hours, but the percentage of S phase cells in Sk-hep1 cells transfected with Sirpα1 was the lowest ( vs pLXSN and Sirpα1Δ4Y2 Sk- hepl, P<0.05). The percentage of S phase cells in trans- fected pLSXN Sk-hep1 cells was the largest (vs Sirpα1 and Sirpα1Δ4Y2 Sk-hepl, P <0. 05). There was no significant difference between the transfected Sirpα1 Sk-hepl cells and Sirpα1Δ4Y2 Sk-hep1 cells (P>0.05). CONCLUSIONS: Sirpα1 decreases gankyrin and cyclin D1 expression, and inhibits proliferation of liver carcinoma cells. It may be one of the forms for an Sirpα1 negative regulation of carcinogenesis and development of hepatocel- lular carcinoma.展开更多
According to the report of the International Diabetes Federation, there were 382 million people affected with diabetes in 2013 and it is expected that this number will increase to 592 million by the year 2035;. Diabet...According to the report of the International Diabetes Federation, there were 382 million people affected with diabetes in 2013 and it is expected that this number will increase to 592 million by the year 2035;. Diabetes is caused due to the interaction between environmental and genetic factors;.展开更多
BACKGROUND Study shows that signal transducer and activator of transcription 3(STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate de...BACKGROUND Study shows that signal transducer and activator of transcription 3(STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 in myeloma. STAT3 and pyruvate kinase M2(PKM2) can also be activated and enhance the Warburg effect in hepatocellular carcinoma. Precancerous lesions are critical to human and rodent hepatocarcinogenesis. However, the underlying molecular mechanism for the development of liver precancerous lesions remains unknown. We hypothesized that STAT3 promotes the Warburg effect possibly by upregulating p-PKM2 in liver precancerous lesions in rats.AIM To investigate the mechanism of the Warburg effect in liver precancerous lesions in rats.METHODS A model of liver precancerous lesions was established by a modified Solt-Farber method. The liver pathological changes were observed by HE staining and immunohistochemistry. The transformation of WB-F344 cells induced with Nmethyl-N'-nitro-N-nitrosoguanidine and hydrogen peroxide was evaluated by the soft agar assay and aneuploidy. The levels of glucose and lactate in the tissue and culture medium were detected with a spectrophotometer. The protein levels of glutathione S-transferase-π, proliferating cell nuclear antigen(PCNA), STAT3,and PKM2 were examined by Western blot and immunofluorescence.RESULTS We found that the Warburg effect was increased in liver precancerous lesions in rats. PKM2 and p-STAT3 were upregulated in activated oval cells in liverprecancerous lesions in rats. The Warburg effect, p-PKM2, and p-STAT3 expression were also increased in transformed WB-F344 cells. STAT3 activation promoted the clonal formation rate, aneuploidy, alpha-fetoprotein expression,PCNA expression, G1/S phase transition, the Warburg effect, PKM2 phosphorylation, and nuclear translocation in transformed WB-F344 cells.Moreover, the Warburg effect was inhibited by stattic, a specific inhibitor of STAT3, and further reduced in transformed WB-F344 cells after the intervention for PKM2.CONCLUSION The Warburg effect is initiated in liver precancerous lesions in rats. STAT3 activation promotes the Warburg effect by enhancing the phosphorylation of PKM2 in transformed WB-F344 cells.展开更多
In radar system simulation,the reliability of simulation results depends not only on radar and target models,but also on radio frequency (RF) environment models,including clutter,multipath,diffraction,atmosphere refra...In radar system simulation,the reliability of simulation results depends not only on radar and target models,but also on radio frequency (RF) environment models,including clutter,multipath,diffraction,atmosphere refraction and attenuation.In traditional radar function simulation,all of these factors are grouped into a single pattern-propagation factor and can only give limited information for radar models.In signal-level simulation,radar models require simulated echoes should include information such as delay,doppler frequency,polarization,etc.By discussing and analyzing the principles and algorithms of RF environment effects (clutter,multipath,diffraction,atmosphere refraction and attenuation),this paper is supposed to provide a general RF environment model in signal-level.Algorithms for the Weibull clutter with Gaussian power spectral density (PSD) is discussed;A standard multipath and diffraction algorithm is analyzed,and the spherical earth and knife edge(SEKE)diffraction algorithm is introduced;The ray-tracing algorithm and the effective earth model are discussed;Algorithms for the absorption of oxygen and vapor are introduced;For certain algorithms,some practical advice is given.Finally,an object-oriented RF environment effects model is implemented,which has been dedicatedly designed for signal-level simulations and can provide relatively authentic simulated RF environment for the signal-level simulation of radar systems.Two simulation examples including clutter model and multipath and diffraction model are carried out and analyzed.展开更多
In the future the fifth generation( 5 G) communication systems,channel models may be very complicated and it is difficult to calculate equivalent signal to interference plus noise ratio( SINR)of a random fading channe...In the future the fifth generation( 5 G) communication systems,channel models may be very complicated and it is difficult to calculate equivalent signal to interference plus noise ratio( SINR)of a random fading channel. Therefore,methods for the calculation of equivalent SINR of a random fading channel are very necessary.In this paper,an enhanced algorithm on the exponential effective SINR mapping( EESM) model for random fading channels was proposed. First, the optimal adjustment parameters of typical channel fading models including extended pedestrian A( EPA)model,extended vehicular A( EVA) model and extended typical urban( ETU) model were obtained by simulation. Then the proposed solution was used to actualize channel classification according to the maximum multipath delay and the average power of the random channel. The solution can determine the typical channel closest to random channel for obtaining the optimal adjustment value of EESM. The evaluation results indicate that the proposed one can improve the whole system throughput significantly and meanwhile the accuracy of the link prediction algorithm is also guaranteed.展开更多
BACKGROUND Intestinal inflammation is a common digestive tract disease, which is usually treated with hormone medicines. Hormone medicines are effective to some extent, but long-term use of them may bring about many c...BACKGROUND Intestinal inflammation is a common digestive tract disease, which is usually treated with hormone medicines. Hormone medicines are effective to some extent, but long-term use of them may bring about many complications.AIM To explore the protective effects of panax notoginseng saponin(PNS) against dextran sulfate sodium(DSS)-induced intestinal inflammatory injury through phosphoinositide-3-kinase protein kinase B(PI3K/AKT) signaling pathway inhibition in rats.METHODS Colitis rat models were generated via DSS induction, and rats were divided into control(no modeling), DSS, DSS + PNS 50 mg/k, and DSS + PNS 100 mg/kg groups. Then, the intestinal injury, oxidative stress parameters, inflammatory indices, tight junction proteins, apoptosis, macrophage polarization, and TLR4/AKT signaling pathway in colon tissues from rats in each of the groups were detected. The PI3 K/AKT signaling pathway in the colon tissue of rats was blocked using the PI3K/AKT signaling pathway inhibitor, LY294002.RESULTS Compared with rats in the control group, rats in the DSS group showed significantly shortened colon lengths, and significantly increased disease activity indices, oxidative stress reactions and inflammatory indices, as well as significantly decreased expression of tight junction-associated proteins. In addition, the DSS group showed significantly increased apoptotic cell numbers,and showed significantly increased M1 macrophages in spleen and colon tissues.They also showed significantly decreased M2 macrophages in colon tissues, as well as activation of the PI3K/AKT signaling pathway(all P < 0.05). Compared with rats in the DSS group, rats in the DSS + PNS group showed significantly lengthened colon lengths, decreased disease activity indices, and significantly alleviated oxidative stress reactions and inflammatory responses. In addition, this group showed significantly increased expression of tight junction-associated proteins, significantly decreased apoptotic cell numbers, and significantly decreased M1 macrophages in spleen and colon tissues. This group further showed significantly increased M2 macrophages in colon tissues, and significantly suppressed activation of the PI3K/AKT signaling pathway, as well as a dose dependency(all P < 0.05). When the PI3K/AKT signaling pathway was inhibited, the apoptosis rate of colon tissue cells in the DSS + LY294002 group was significantly lower than that of the DSS group(P < 0.05).CONCLUSION PNS can protect rats against DSS-induced intestinal inflammatory injury by inhibiting the PI3K/AKT signaling pathway, and therefore may be potentially used in the future as a drug for colitis.展开更多
现有基于虚拟正弦信号注入(virtual sine signal injection,VSSI)的最大转矩电流比(maximum torque per ampere,MTPA)控制方法以理想永磁同步电动机(permanent magnet synchronous machine,PMSM)数学模型为理论基础,未考虑电感变化带来...现有基于虚拟正弦信号注入(virtual sine signal injection,VSSI)的最大转矩电流比(maximum torque per ampere,MTPA)控制方法以理想永磁同步电动机(permanent magnet synchronous machine,PMSM)数学模型为理论基础,未考虑电感变化带来的不利影响。为了提升MTPA控制效果,增加考虑磁路交叉耦合效应,提出在线电感辨识方法和改进的MTPA控制方法。基于帕德逼近与变步长神经网络的电感辨识方法,不仅可以解决辨识模型欠秩问题,而且能够在线更新变化的电感参数,结合改进的基于VSSI的MTPA控制,可以有效降低电流矢量角误差,减小定子铜损耗,实现更准确的MTPA控制。通过仿真实验对所提方法的准确性进行了验证。展开更多
微波混频器是高端微波接收机射频前端的核心敏感器件,当其作为直接混频式前端接收方式“前门”第一级时,极易因高功率微波(high power microwave,HPM)辐射而受损。HPM对微波混频器的损伤敏感指标参数是变频损耗,主要损伤结果为变频损耗...微波混频器是高端微波接收机射频前端的核心敏感器件,当其作为直接混频式前端接收方式“前门”第一级时,极易因高功率微波(high power microwave,HPM)辐射而受损。HPM对微波混频器的损伤敏感指标参数是变频损耗,主要损伤结果为变频损耗增大、接收链路增益和系统灵敏度降低,最终影响系统使用效能。本文将变频损耗与相位差作为微波混频器HPM损伤效应的主要评估指标,并提出了基于相同中频信号幅度下射频信号功率比的微波混频器HPM损伤效应测试评估方法,为非线性器件HPM损伤效应研究提供了规范化技术途径。展开更多
In order to deal with the non-stationary characteristics of blasting vibration signals and the end issue in the empirical mode decomposition(EMD), an improved endpoint continuation method is proposed. First, the linea...In order to deal with the non-stationary characteristics of blasting vibration signals and the end issue in the empirical mode decomposition(EMD), an improved endpoint continuation method is proposed. First, the linear continuation method of extreme points is used to determine the extremum of the signal endpoint fast. Secondly, the extreme points of transition section outside the signal ends are obtained by a mirror continuation method of extreme points, and then the envelope and continuation curve of the transition section of the signal are constructed. Lastly, the sinusoid of the stationary section outside the signal is constructed to achieve the continuation curve from the transition section to the stationary section. Based on the "singular extreme points" phenomenon of blasting vibration signal, the negative maxima and positive minimum are eliminated, then the maximum and minimum are guaranteed to appear at intervals. Thus,the number of iterations is reduced and the instability of EMD decomposition is improved. The calculation formula of amplitude, cycle and initial phase are given for the transition section and stationary section outside the signal. The endpoint processing effect of the simulated signal and the measured blasting vibration signal show that the improved endpoint continuation method can suppress the signal endpoint effect well.展开更多
Taking the relativistic effect of high velocity moving target into account, the Doppler shift, polarization deflection, reflection coefficient and phase delay of reflected electric field are analyzed rigorously under...Taking the relativistic effect of high velocity moving target into account, the Doppler shift, polarization deflection, reflection coefficient and phase delay of reflected electric field are analyzed rigorously under the assumptions that incident signal to the target is a plane wave and the target is a perfect conductor plane; and their analytic expressions are obtained. The present results are of practical significance to some extent for the accurate expression of the wideband returned signal of a high velocity moving target in the bistatic radar system and for the understanding of wideband ambiguity functions.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.71101098)the Beijing Municipal Education Commission Foundation of China (Grant Nos. SM201210038008 and 00791154430107)the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (Grant No.PHR201007117)
文摘In real traffic,any vehicle must give lane-changing signal(i.e.the turn signal) before changing lanes;at this time,the vehicles behind the lane-changing vehicle will be hindered and may form "plugs" due to the turn signal effect.However,few studies focus on exploring the effect.In this paper,the turn signal effect was taken into account by proposing a new symmetric two-lane cellular automaton(T-STCA) model,and the new model was set to compare with the STCA,H-STCA and A-STCA models.Numerical results show that using the T-STCA model to describe lane-changing or overtaking,the process appeared in several consecutive time steps;while using the other three models,the process appeared only in one time step.In addition,the T-STCA model could describe the mixed traffic flow more realistically and the turn signal effect could help the plugs to dissolve more quickly.
文摘Supply chain partnerships are an essential component of business innovations.This study uses data on A-share listed companies on the Shanghai and Shenzhen stock exchanges from 2012 to 2022 to conduct a multi-period difference-in-differences analysis based on a list of green supply chain management(GSM)companies.We find that GSM significantly promotes low-carbon technology innovations(LCT)of upstream enterprises.The mechanism analysis indicates that GSM has a resource effect and signal effect that generate LCT spillovers.In terms of the resource effect,GSM companies offer green credit and support green procurement,thereby providing financial support for green investments in upstream LCT.In terms of a signaling effect,GSM strengthens the effectiveness of institutional investors,the public,and online media in supervising upstream suppliers’green credentials,thereby promoting upstream LCT.A heterogeneity analysis shows that when midstream companies are state-owned enterprises or industry leaders,and when the concentration and stability of supply chain purchase relationships are higher,the LCT spillover effects of GSM are more pronounced.Further analysis reveals that GSM has bidirectional horizontal spillover effects and that upstream unidirectional vertical spillover effects are limited to first-level suppliers.Additionally,under the premise of not compromising economic benefits and stability,GSM shows an emerging trend of transitioning from environmentally compliant“light green”supply chains to“deep green”supply chains focused on pollution reduction,carbon reduction,and energy conservation.
文摘Objective: To investigate the autophagy-inducing effect of Compound Berberine (CBBR) on CNE2 nasopharyngeal carcinoma (NPC) cells and its possible targets in P13K/AKT/mTOR signaling pathway. Methods: CNE2 cells at exponential growth phase were taken as the target cells in this study. Firstly, IC50 concentration for CBBR was determined by MTT assay. Then, 3 different concentrations of CBBR, 0.25 mg⋅mL−1, 0.50 mg⋅mL−1 and 1.00 mg⋅mL−1, around the concentration of IC50, were taken for followed intervention experiments respectively. Fluorescein labeling method was utilized to assay the inducing effect of CBBR on the autophagic activity of CNE2 cells, followed by Western blot procedure to explore the changes of key messenger molecules in the autophagy-related signaling pathway of P13K/AKT/mTOR, both combined with 3-MA block test in a comparative way and carried out by detecting the expressive levels of Beclin 1, LC3-II and LC3-I as well as the ratio of LC3-II:LC3-I. Results: IC50 of CBBR was determined at the level of 0.5 mg⋅mL−1. The inducing effect of CBBR on autophagy of CNE2 cells was shown occurring in various modes, not a simple concentration-dependent tendency, with its effect minimal at the concentration of 0.25 mg⋅mL−1 and maximal at the concentration of 0.50 mg⋅mL−1, while only slightly higher at the concentration of 1.00 mg⋅mL−1 than that of 0.5 mg⋅mL−1. Although its inducing effect was weakened a little following the pretreatment by 3-MA, the effect combined with CBBR was still significantly higher than that of simply blocked by 3-MA. Moreover, changes in the expressive levels of Beclin1, LC3-II and LC3-I as well as LC3-II:LC3-I all showed a tendency corresponding to the changed autophagic features of CNE2 cells (P Conclusions: CBBR can bring about inhibiting effect on the proliferating activity of CNE2 cells through inducing increased autophagic activity via intervening targets in P13K/AKT/mTOR signaling pathway, and this effect could not be completely blocked by the antagonist 3-MA.
基金Project (10276032) supportedjointly by the National Natural Science Foundation of China and by the Science Foundationof China Academy of Engineering Physics NSAFproject(2005038228) supported by Postdoctoral Science Foundation of China projectsupported by the Postdoctoral Science Foundation of Central South University(2005)
文摘The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small system parameters. An analogue circuit was designed to perform the effect. The effect of signal modulating noise was shown in the analog simulation experiment. The analog experiment was conducted for two sinusoidal signals with different frequencies. The results show that there are a sinusoidal component corresponding to the input sinusoidal signal and a noise component presented as a Wiener process corresponding to the input white noise in the system output. By properly selecting system parameters, the effect of signal modulating noise can be manifested in the system output.
基金This work is supported by National Natural Science Fundation.
文摘The effect of signal sampling depth in SIMS on profile was not reported We have found that the maximum sampling depth in SIMS is considerably bigger than the mean penetration range of primary ions and can skew the profile of secondary ion counts for implanted samples on the more deeper direction from the surface. The effect of maximum sampling depth is true not only for implanted samples but also for the samples in the middle of which there is an other impurity-rich layer. The action principle of signal sampling depth effect and the method of decreasing the error produced by the effect are discussed in this
基金This work was supported by a grant from the NationalNatural Science Foundation of China (No. 30000159).
文摘BACKGROUND: Signal regulatory protein alpha1 (Sirpα1) is a negative regulatory factor, and inhibits receptor tyro- sine kinase-dependent cell proliferating signal. This study was undertaken to observe the effect of signal regulatory proteinα1 ( Sirpα1) on gankyrin, cyclin D1, CDK4 and Fas expression in Sk-hep1 mouse hepatoma carcinoma cell line. METHODS: BOSC 23 packed cells were respectively trans- fected by means of recombinated retrovirus including pLX- SN, pLXSN-Sirpα1 and pLXSN-Sirpα1Δ4Y2 with lipofec- tin, and various plasmid virus media (viral titer 2.1 × 106 CFU/ml) were collected and infected respectively in 80% confluent Sk-hepl cells. Transfected Sk-hep1 cells were se- lectively screened with G418 (1200 μg/ml), and Sk-hep1 cell lines transfected with various plasmids were obtained. The protein expressions of gankyrin, cyclin D1, CDK4 and Fas in various Sk-hep1 lines were determined by Western blotting. Various Sk-hep1 lines were recovered to culture with 10% fetal bovine serum at 12 hours and 24 hours after starving culture with free serum for 72 hours, and cells were collected to determine the percentage of S phase cells of proliferating cycle by flow cytometry. RESULTS: Sirpα1 transfection remarkably downregulated gankyrin and cyclin D1 expression. Sirpα1Δ4Y2 downregu- lation of gankyrin expression was greater than that of Sirpα1(P <0.05), but no significant effect of Sirpα1 and Sirpα1Δ4Y2 on CDK4 and Fas protein expression was ob- served in transfected Sk-hep1 lines (P >0.05). The per- centage of S phase cells significantly decreased in Sk-hep1 cells transfected with Sirpα1 and Sirpα1Δ4Y2 plasmids (vs pLXSN Sk-hep1, P <0.05). The percentage of S phase cells in various Sk-hep1 cells increased when recovering to culture with 10% fetal bovine serum at 12 hours, but the percentage of S phase cells in Sk-hep1 cells transfected with Sirpα1 was the lowest ( vs pLXSN and Sirpα1Δ4Y2 Sk- hepl, P<0.05). The percentage of S phase cells in trans- fected pLSXN Sk-hep1 cells was the largest (vs Sirpα1 and Sirpα1Δ4Y2 Sk-hepl, P <0. 05). There was no significant difference between the transfected Sirpα1 Sk-hepl cells and Sirpα1Δ4Y2 Sk-hep1 cells (P>0.05). CONCLUSIONS: Sirpα1 decreases gankyrin and cyclin D1 expression, and inhibits proliferation of liver carcinoma cells. It may be one of the forms for an Sirpα1 negative regulation of carcinogenesis and development of hepatocel- lular carcinoma.
基金partially supported by Jipai Runda Environmental Inspection Technology Corporation Limited of Beijing [Grant No.2016YX137]the grant of research on management model of common chronic diseases [Grant No.371182093427]
文摘According to the report of the International Diabetes Federation, there were 382 million people affected with diabetes in 2013 and it is expected that this number will increase to 592 million by the year 2035;. Diabetes is caused due to the interaction between environmental and genetic factors;.
基金supported by the National Science Foundation of China[grant number 42025503]the National Key R&D Program of China[grant number 2018YFA0605604]the Key Innovation Team of the China Meteorological Administration[grant number CMA2022ZD03].
基金Supported by the National Natural Science Foundation of China,No.81070319the Beijing Natural Science Foundation of China,No.7102013the Beijing Municipal Education Commission Research Program,China,No.KM201610025004
文摘BACKGROUND Study shows that signal transducer and activator of transcription 3(STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 in myeloma. STAT3 and pyruvate kinase M2(PKM2) can also be activated and enhance the Warburg effect in hepatocellular carcinoma. Precancerous lesions are critical to human and rodent hepatocarcinogenesis. However, the underlying molecular mechanism for the development of liver precancerous lesions remains unknown. We hypothesized that STAT3 promotes the Warburg effect possibly by upregulating p-PKM2 in liver precancerous lesions in rats.AIM To investigate the mechanism of the Warburg effect in liver precancerous lesions in rats.METHODS A model of liver precancerous lesions was established by a modified Solt-Farber method. The liver pathological changes were observed by HE staining and immunohistochemistry. The transformation of WB-F344 cells induced with Nmethyl-N'-nitro-N-nitrosoguanidine and hydrogen peroxide was evaluated by the soft agar assay and aneuploidy. The levels of glucose and lactate in the tissue and culture medium were detected with a spectrophotometer. The protein levels of glutathione S-transferase-π, proliferating cell nuclear antigen(PCNA), STAT3,and PKM2 were examined by Western blot and immunofluorescence.RESULTS We found that the Warburg effect was increased in liver precancerous lesions in rats. PKM2 and p-STAT3 were upregulated in activated oval cells in liverprecancerous lesions in rats. The Warburg effect, p-PKM2, and p-STAT3 expression were also increased in transformed WB-F344 cells. STAT3 activation promoted the clonal formation rate, aneuploidy, alpha-fetoprotein expression,PCNA expression, G1/S phase transition, the Warburg effect, PKM2 phosphorylation, and nuclear translocation in transformed WB-F344 cells.Moreover, the Warburg effect was inhibited by stattic, a specific inhibitor of STAT3, and further reduced in transformed WB-F344 cells after the intervention for PKM2.CONCLUSION The Warburg effect is initiated in liver precancerous lesions in rats. STAT3 activation promotes the Warburg effect by enhancing the phosphorylation of PKM2 in transformed WB-F344 cells.
文摘In radar system simulation,the reliability of simulation results depends not only on radar and target models,but also on radio frequency (RF) environment models,including clutter,multipath,diffraction,atmosphere refraction and attenuation.In traditional radar function simulation,all of these factors are grouped into a single pattern-propagation factor and can only give limited information for radar models.In signal-level simulation,radar models require simulated echoes should include information such as delay,doppler frequency,polarization,etc.By discussing and analyzing the principles and algorithms of RF environment effects (clutter,multipath,diffraction,atmosphere refraction and attenuation),this paper is supposed to provide a general RF environment model in signal-level.Algorithms for the Weibull clutter with Gaussian power spectral density (PSD) is discussed;A standard multipath and diffraction algorithm is analyzed,and the spherical earth and knife edge(SEKE)diffraction algorithm is introduced;The ray-tracing algorithm and the effective earth model are discussed;Algorithms for the absorption of oxygen and vapor are introduced;For certain algorithms,some practical advice is given.Finally,an object-oriented RF environment effects model is implemented,which has been dedicatedly designed for signal-level simulations and can provide relatively authentic simulated RF environment for the signal-level simulation of radar systems.Two simulation examples including clutter model and multipath and diffraction model are carried out and analyzed.
基金Institute of Nonlinear Science of Donghua University,China
文摘In the future the fifth generation( 5 G) communication systems,channel models may be very complicated and it is difficult to calculate equivalent signal to interference plus noise ratio( SINR)of a random fading channel. Therefore,methods for the calculation of equivalent SINR of a random fading channel are very necessary.In this paper,an enhanced algorithm on the exponential effective SINR mapping( EESM) model for random fading channels was proposed. First, the optimal adjustment parameters of typical channel fading models including extended pedestrian A( EPA)model,extended vehicular A( EVA) model and extended typical urban( ETU) model were obtained by simulation. Then the proposed solution was used to actualize channel classification according to the maximum multipath delay and the average power of the random channel. The solution can determine the typical channel closest to random channel for obtaining the optimal adjustment value of EESM. The evaluation results indicate that the proposed one can improve the whole system throughput significantly and meanwhile the accuracy of the link prediction algorithm is also guaranteed.
基金National Natural Science Foundation of China,No.81704059Scientific Research Project of Hebei Province Traditional Chinese Medicine Administration,No.2017130。
文摘BACKGROUND Intestinal inflammation is a common digestive tract disease, which is usually treated with hormone medicines. Hormone medicines are effective to some extent, but long-term use of them may bring about many complications.AIM To explore the protective effects of panax notoginseng saponin(PNS) against dextran sulfate sodium(DSS)-induced intestinal inflammatory injury through phosphoinositide-3-kinase protein kinase B(PI3K/AKT) signaling pathway inhibition in rats.METHODS Colitis rat models were generated via DSS induction, and rats were divided into control(no modeling), DSS, DSS + PNS 50 mg/k, and DSS + PNS 100 mg/kg groups. Then, the intestinal injury, oxidative stress parameters, inflammatory indices, tight junction proteins, apoptosis, macrophage polarization, and TLR4/AKT signaling pathway in colon tissues from rats in each of the groups were detected. The PI3 K/AKT signaling pathway in the colon tissue of rats was blocked using the PI3K/AKT signaling pathway inhibitor, LY294002.RESULTS Compared with rats in the control group, rats in the DSS group showed significantly shortened colon lengths, and significantly increased disease activity indices, oxidative stress reactions and inflammatory indices, as well as significantly decreased expression of tight junction-associated proteins. In addition, the DSS group showed significantly increased apoptotic cell numbers,and showed significantly increased M1 macrophages in spleen and colon tissues.They also showed significantly decreased M2 macrophages in colon tissues, as well as activation of the PI3K/AKT signaling pathway(all P < 0.05). Compared with rats in the DSS group, rats in the DSS + PNS group showed significantly lengthened colon lengths, decreased disease activity indices, and significantly alleviated oxidative stress reactions and inflammatory responses. In addition, this group showed significantly increased expression of tight junction-associated proteins, significantly decreased apoptotic cell numbers, and significantly decreased M1 macrophages in spleen and colon tissues. This group further showed significantly increased M2 macrophages in colon tissues, and significantly suppressed activation of the PI3K/AKT signaling pathway, as well as a dose dependency(all P < 0.05). When the PI3K/AKT signaling pathway was inhibited, the apoptosis rate of colon tissue cells in the DSS + LY294002 group was significantly lower than that of the DSS group(P < 0.05).CONCLUSION PNS can protect rats against DSS-induced intestinal inflammatory injury by inhibiting the PI3K/AKT signaling pathway, and therefore may be potentially used in the future as a drug for colitis.
文摘现有基于虚拟正弦信号注入(virtual sine signal injection,VSSI)的最大转矩电流比(maximum torque per ampere,MTPA)控制方法以理想永磁同步电动机(permanent magnet synchronous machine,PMSM)数学模型为理论基础,未考虑电感变化带来的不利影响。为了提升MTPA控制效果,增加考虑磁路交叉耦合效应,提出在线电感辨识方法和改进的MTPA控制方法。基于帕德逼近与变步长神经网络的电感辨识方法,不仅可以解决辨识模型欠秩问题,而且能够在线更新变化的电感参数,结合改进的基于VSSI的MTPA控制,可以有效降低电流矢量角误差,减小定子铜损耗,实现更准确的MTPA控制。通过仿真实验对所提方法的准确性进行了验证。
文摘微波混频器是高端微波接收机射频前端的核心敏感器件,当其作为直接混频式前端接收方式“前门”第一级时,极易因高功率微波(high power microwave,HPM)辐射而受损。HPM对微波混频器的损伤敏感指标参数是变频损耗,主要损伤结果为变频损耗增大、接收链路增益和系统灵敏度降低,最终影响系统使用效能。本文将变频损耗与相位差作为微波混频器HPM损伤效应的主要评估指标,并提出了基于相同中频信号幅度下射频信号功率比的微波混频器HPM损伤效应测试评估方法,为非线性器件HPM损伤效应研究提供了规范化技术途径。
基金Supported by the National Natural Science Foundation of China(51374212)
文摘In order to deal with the non-stationary characteristics of blasting vibration signals and the end issue in the empirical mode decomposition(EMD), an improved endpoint continuation method is proposed. First, the linear continuation method of extreme points is used to determine the extremum of the signal endpoint fast. Secondly, the extreme points of transition section outside the signal ends are obtained by a mirror continuation method of extreme points, and then the envelope and continuation curve of the transition section of the signal are constructed. Lastly, the sinusoid of the stationary section outside the signal is constructed to achieve the continuation curve from the transition section to the stationary section. Based on the "singular extreme points" phenomenon of blasting vibration signal, the negative maxima and positive minimum are eliminated, then the maximum and minimum are guaranteed to appear at intervals. Thus,the number of iterations is reduced and the instability of EMD decomposition is improved. The calculation formula of amplitude, cycle and initial phase are given for the transition section and stationary section outside the signal. The endpoint processing effect of the simulated signal and the measured blasting vibration signal show that the improved endpoint continuation method can suppress the signal endpoint effect well.
文摘Taking the relativistic effect of high velocity moving target into account, the Doppler shift, polarization deflection, reflection coefficient and phase delay of reflected electric field are analyzed rigorously under the assumptions that incident signal to the target is a plane wave and the target is a perfect conductor plane; and their analytic expressions are obtained. The present results are of practical significance to some extent for the accurate expression of the wideband returned signal of a high velocity moving target in the bistatic radar system and for the understanding of wideband ambiguity functions.
