Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inhe...Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inherent imaginary interference (IMI). This has an important impact on the channel estimation process. Currently, a variety of frequency-domain channel estimation methods have been proposed. However, there are various problems that still exist. For instance, in order to reduce the influence of IMI, it is necessary to insert more guard intervals between the training sequence and the payload, leading to the occupation of excessive spectrum resources. In order to address this problem, this work designs a high spectral efficient frequency-domain channel estimation method for the polarization-division-multiplexing CO-OFDM-OQAM systems. First, the working principle of the proposed method is described in detail. Then, its spectral efficiency, power peak-to-average ratio, and channel estimation performance are studied based on simulations. The simulation results show that the proposed method improves the spectral efficiency without worsening the power peak-to-average ratio. The channel estimation capability of this method is verified in three scenarios of long-distance transmissions, including back-to-back, 100 km, and 200 km transmissions. .展开更多
OBJECTIVE To investigate the expression of TGF-β1,Snail,E-cad-herin and N-cadherin in gastric cancer(GC),and to examine its relationship to malignant features of the tumors. METHODS The expression of TGF-β1,Snail,E-...OBJECTIVE To investigate the expression of TGF-β1,Snail,E-cad-herin and N-cadherin in gastric cancer(GC),and to examine its relationship to malignant features of the tumors. METHODS The expression of TGF-β1,Snail,E-cadherin and N-cadherin proteins was detected in GC and adjacent tissues by immunohistochemical staining,and compared with the clinico-pathological data. RESULTS Positive rates of expression for TGF-β1,Snail,E-cadherin and N-cadherin were 63.5%,83.3%,37.5%and 44.8%in GC,and 28.8%, 41.3%,100%,11.3%in adjacent tissues,respectively.The expression of all four proteins showed a significant difference between the GCs and adjacent tissues(P<0.05).The positive rate of TGF-β1,Snail and N-cadherin,or the negative rate of E-cadherin expression was significantly related to the differentiated degree,histological type,invasion and metastasis of GC.In addition,the expression of N-cadherin was positively related to that of TGF-β1, but negatively related to that of E-cadherin.There was negative correlation between expression of E-cadherin and TGF-β1 and Snail in GC(P<0.05). CONCLUSION The over-expression of TGF-β1 and Snail and decreased expression of E-cadherin and the abnormal expression of N-cad-herin were involved in the process of invasion and metastasis of GC.The data showed that E-cadherin might switch to N-cadherin.TGF-β1 and Snail might play a fundamental role in the process.展开更多
In this paper,we describe a new method to improve fast-light transmission,which uses cascades.We design a simple plasmonic device that enables plasmonic-induced absorption(PIA).It consists mainly of two parallel recta...In this paper,we describe a new method to improve fast-light transmission,which uses cascades.We design a simple plasmonic device that enables plasmonic-induced absorption(PIA).It consists mainly of two parallel rectangular cavities.The numerical results simulated by using the finite element method(FEM)confirm its function.The corresponding group delay-time can reach-0.146 ps for the PIA window.Based on this result,we propose a cascade device,with the dual-rectangular cavity system as building block,to improve fast-light transmission even more.The results indicate that the cascade scheme can increase the group delay-time to-0.456 ps,which means the fast-light feature is substantially enhanced compared with the non-cascading approach.The effect of the distance between two cascade resonators and other structural parameters is also investigated.Finally,we use this design concept to build a refractive-index sensor with a sensitivity of 701 nm/RIU.展开更多
文摘Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inherent imaginary interference (IMI). This has an important impact on the channel estimation process. Currently, a variety of frequency-domain channel estimation methods have been proposed. However, there are various problems that still exist. For instance, in order to reduce the influence of IMI, it is necessary to insert more guard intervals between the training sequence and the payload, leading to the occupation of excessive spectrum resources. In order to address this problem, this work designs a high spectral efficient frequency-domain channel estimation method for the polarization-division-multiplexing CO-OFDM-OQAM systems. First, the working principle of the proposed method is described in detail. Then, its spectral efficiency, power peak-to-average ratio, and channel estimation performance are studied based on simulations. The simulation results show that the proposed method improves the spectral efficiency without worsening the power peak-to-average ratio. The channel estimation capability of this method is verified in three scenarios of long-distance transmissions, including back-to-back, 100 km, and 200 km transmissions. .
基金This work was supported by a grant from theKey Science and Technology Fund,Govern-mental Department of Education,Anhui Prov-ince(No.kj2007A029)
文摘OBJECTIVE To investigate the expression of TGF-β1,Snail,E-cad-herin and N-cadherin in gastric cancer(GC),and to examine its relationship to malignant features of the tumors. METHODS The expression of TGF-β1,Snail,E-cadherin and N-cadherin proteins was detected in GC and adjacent tissues by immunohistochemical staining,and compared with the clinico-pathological data. RESULTS Positive rates of expression for TGF-β1,Snail,E-cadherin and N-cadherin were 63.5%,83.3%,37.5%and 44.8%in GC,and 28.8%, 41.3%,100%,11.3%in adjacent tissues,respectively.The expression of all four proteins showed a significant difference between the GCs and adjacent tissues(P<0.05).The positive rate of TGF-β1,Snail and N-cadherin,or the negative rate of E-cadherin expression was significantly related to the differentiated degree,histological type,invasion and metastasis of GC.In addition,the expression of N-cadherin was positively related to that of TGF-β1, but negatively related to that of E-cadherin.There was negative correlation between expression of E-cadherin and TGF-β1 and Snail in GC(P<0.05). CONCLUSION The over-expression of TGF-β1 and Snail and decreased expression of E-cadherin and the abnormal expression of N-cad-herin were involved in the process of invasion and metastasis of GC.The data showed that E-cadherin might switch to N-cadherin.TGF-β1 and Snail might play a fundamental role in the process.
基金supported by the National Natural Science Foundation of China(Grant No.61367007)the Natural Science Fund of Gansu Province of China(Grant Nos.17JR5RA123 and 17JR5RA132)the HongLiu First-Class disciplines Development Program of Lanzhou University of Technology.
文摘In this paper,we describe a new method to improve fast-light transmission,which uses cascades.We design a simple plasmonic device that enables plasmonic-induced absorption(PIA).It consists mainly of two parallel rectangular cavities.The numerical results simulated by using the finite element method(FEM)confirm its function.The corresponding group delay-time can reach-0.146 ps for the PIA window.Based on this result,we propose a cascade device,with the dual-rectangular cavity system as building block,to improve fast-light transmission even more.The results indicate that the cascade scheme can increase the group delay-time to-0.456 ps,which means the fast-light feature is substantially enhanced compared with the non-cascading approach.The effect of the distance between two cascade resonators and other structural parameters is also investigated.Finally,we use this design concept to build a refractive-index sensor with a sensitivity of 701 nm/RIU.
