根据磁共振(MRS)信号在频域呈现的特点,提出一种频域对称法,用作传统消噪流程的补充步骤以消除残余噪声。首先,对含噪信号进行频域解调,分解为实时域分量和虚时域分量;然后,利用2个分量的频谱在工频噪声频率处相同、负频率处相反的特点...根据磁共振(MRS)信号在频域呈现的特点,提出一种频域对称法,用作传统消噪流程的补充步骤以消除残余噪声。首先,对含噪信号进行频域解调,分解为实时域分量和虚时域分量;然后,利用2个分量的频谱在工频噪声频率处相同、负频率处相反的特点,估算与MRS探测信号混叠的工频噪声实部分量,与虚时域分量同步剔除,达到信噪分离的目的。研究结果表明:采用频域对称法消除残余噪声后,数据信噪比由15.29 dB提升至19.33 d B,初始振幅提取相对误差由2.03%减小为0.86%,弛豫时间提取相对误差由5.53%减小为2.27%。相较于传统MRS消噪方法,采用频域对称法可以进一步消除残余噪声,提高信号信噪比。展开更多
CKLF (chemokine-like factor)-like MARVEL (MAL and related proteins for vesicle trafficking and mem-brane link domain) transmembrane domain containing (CMTM) is a novel gene family. One member of this family, CMTM2, al...CKLF (chemokine-like factor)-like MARVEL (MAL and related proteins for vesicle trafficking and mem-brane link domain) transmembrane domain containing (CMTM) is a novel gene family. One member of this family, CMTM2, also named chemokine-like factor superfamily 2 (CKLFSF2), is expressed highly in the testis and moderately in the prostate, marrow and peripheral blood cells. However, the function of human CMTM2 remains unknown. Here, we found that CMTM2 was upregulated in 5α-dihydrotestos- terone (DHT)-treated LNCaP cells. We investigated the relationship between CMTM2 and the androgen receptor. Our results showed that CMTM2 enhanced DHT-mediated androgen receptor (AR) transacti-vation and the expression of prostate specific antigen (PSA). We also observed that CMTM2 enhanced the AR protein level, which was reversed by silencing endogenous CMTM2 expression, which sug-gested that CMTM2 might play an important role in maintaining the AR protein level. We also found that CMTM2 suppressed Akt activation. A previous study showed that Akt could phosphorylate AR at Ser210 and Ser790 and lead to AR ubiquitylation and degradation as well as suppression of AR activity. Taken together, suppressing Akt activation and increasing the AR protein level might be one of the mechanisms for the CMTM2-mediated enhancement of AR transactivation.展开更多
文摘根据磁共振(MRS)信号在频域呈现的特点,提出一种频域对称法,用作传统消噪流程的补充步骤以消除残余噪声。首先,对含噪信号进行频域解调,分解为实时域分量和虚时域分量;然后,利用2个分量的频谱在工频噪声频率处相同、负频率处相反的特点,估算与MRS探测信号混叠的工频噪声实部分量,与虚时域分量同步剔除,达到信噪分离的目的。研究结果表明:采用频域对称法消除残余噪声后,数据信噪比由15.29 dB提升至19.33 d B,初始振幅提取相对误差由2.03%减小为0.86%,弛豫时间提取相对误差由5.53%减小为2.27%。相较于传统MRS消噪方法,采用频域对称法可以进一步消除残余噪声,提高信号信噪比。
基金Supported by National High Technology Research and Development Program of China (Grant Nos. 2006AA02A305 and 2002BA711A01)National Natural Science Foundation of China (Grant Nos. 30271203 and 30671907)
文摘CKLF (chemokine-like factor)-like MARVEL (MAL and related proteins for vesicle trafficking and mem-brane link domain) transmembrane domain containing (CMTM) is a novel gene family. One member of this family, CMTM2, also named chemokine-like factor superfamily 2 (CKLFSF2), is expressed highly in the testis and moderately in the prostate, marrow and peripheral blood cells. However, the function of human CMTM2 remains unknown. Here, we found that CMTM2 was upregulated in 5α-dihydrotestos- terone (DHT)-treated LNCaP cells. We investigated the relationship between CMTM2 and the androgen receptor. Our results showed that CMTM2 enhanced DHT-mediated androgen receptor (AR) transacti-vation and the expression of prostate specific antigen (PSA). We also observed that CMTM2 enhanced the AR protein level, which was reversed by silencing endogenous CMTM2 expression, which sug-gested that CMTM2 might play an important role in maintaining the AR protein level. We also found that CMTM2 suppressed Akt activation. A previous study showed that Akt could phosphorylate AR at Ser210 and Ser790 and lead to AR ubiquitylation and degradation as well as suppression of AR activity. Taken together, suppressing Akt activation and increasing the AR protein level might be one of the mechanisms for the CMTM2-mediated enhancement of AR transactivation.
