在Kerr媒质中J-C模型的测量相位算符的涨落和压缩

By using the theory of measured phase operator proposed by Barnett and Pegg,dynamic properties of phase of a field are studied.The time evolution and squeezing of measured phase opoerators of a coherent field ineracting with a two-level atom in the cavity with or without the Kerr medium are investigated.The influences of virtual cavity field on squeezing of measured phase operator are studied.Our numerical results show that the squeezing effects are clearly influenced Kerr medium parameters,the field intensity,and the detuning.Moreover,the influence of the virtual-photon field makes more quantum noise in the evolution of measured phase opoerators.     

A study of the relationship between expression level of TRF1 protein and telomerase activity in human acute leukemia

INTRODUCTION Telomeres are distinctive DNA-protein struc-tures that cap the ends of linear chromosomes.It is very important to keep the chromosomes stabilization.Telomerase activity is closely linked to attainment of cellular immortality,a step in carcinogenesis,while lack of such activity contributes to cellular senes-cence.Telomerase is activated in more than85%ofmalignant tumors(Hiayma et al.,1997).Human te-lomeric repeat binding factor1(TRF1)is a telomere associated with proteins a…     

SARS相关冠状病毒与其他已知冠状病毒的膜蛋白的多序列联配

1　Introduction　SARSisthefirstnewlyidentifiedseriousinfectiousdiseasethathumanbeingisfacingatthebeginningofthe 2 1stcentury .Ithasbeen primarilyrecognizedthatavariantofvirusfromthecoronavirusfamilymightbethecandidatepathogenofSARS ,asreportedbyWHO (WorldHealthOrganization)onApril 2 9,2 0 0 3(http ://www .who .int/csr/sarscountry/en) .　Coronaviruseswerefirstisolatedfromchickensin1937.Therearenowapproximately 15speciesinthisfamily.Coronavirusparticlesareirregularlyshaped ,roundabout 6 0 …     

Expression of bone morphogenetic protein 2, 4, and related components of the BMP signaling pathway in the mouse uterus during the estrous cycle

The objective was to investigate the expression of bone morphogenetic protein (BMP) family members in the mouse uterus during the estrous cycle by real-time polymerase chain reaction (PCR) and immunohistochemistry. Uterine samples from Swiss ICR mice were collected and dissected free of surrounding tissue. One uterine horn was snap frozen in liquid nitrogen immediately after collection and stored at −80 °C for RNA extraction, and the other was fixed in 40 mg/ml paraformaldehyde at room temperature for immunolocalization of BMP2 protein. Real-time PCR analysis showed that the expression level of Bmp2 was significantly higher at proestrus than at estrus and metestrus (P<0.05). The relative abundance of Bmp4 exhibited significant fluctuations, but there were no statistically significant differences between the expression levels of Bmp2 and Bmp4 (P>0.05). The expression levels of Bmpr1a and Bmpr2 remained unchanged during estrous cycles. However, the level of Bmpr1b mRNA decreased significantly at estrus (P<0.05), increasing subsequently at metestrus. Furthermore, the level of Bmpr1b mRNA was significantly lower than those of Bmpr1a and Bmpr2 mRNA at the corresponding stages (P<0.05). All three receptor-regulated Smads (R-Smads) detected were differentially expressed in the mouse uterus and the expression levels of Smad1 and Smad5 were significantly higher than that of Smad8 (P<0.05). In addition, the expression level of Smad4 did not change substantially throughout the estrous cycle. Immunohistochemical experiments revealed that BMP2 protein was differentially expressed and localized mainly in the uterine luminal and glandular epithelial cells throughout the estrous cycle. In conclusion, our results provide information about the variation in the mRNA levels of Bmp2 and Bmp4 and related components of the BMP signaling pathway. The data provide quantitative and useful information about the roles of endometrial BMP proposed and demonstrated by others, such as the degradation and remodeling of the endometrium.