Spatial and Wavenumber Resolution of Doppler Reflectometry

Doppler reflectometry spatial and wavenumber resolution is analyzed within the framework of the linear Born approximation in slab plasma model. Explicit expression for its signal backscattering spectrum is obtained in terms of wavenumber and frequency spectra of turbulence which is assumed to be radially statistically inhomogeneous. Scattering efficiency for both back and forward scattering (in radial direction) is introduced and shown to be inverse proportional to the square of radial wavenumber of the probing wave at the fluctuation location thus making the spatial resolution of diagnostics sensitive to density profile. It is shown that in case of forward scattering additional localization can be provided by the antenna diagram. It is demonstrated that in case of backscattering the spatial resolution can be better if the turbulence spectrum at high radial wavenumbers is suppressed. The improvement of Doppler reflectometry data localization by probing beam focusing onto the cut-off is proposed and described. The possibility of Doppler reflectometry data interpretation based on the obtained expressions is shown.Comment: http://stacks.iop.org/0741-3335/46/114

The 3' untranslated regions of two related mRNAs contain an element highly repeated in the sea urchin genome.

Two closely related cDNA clones, pSpec1 and pSpec2, specifying two developmentally regulated tissue specific mRNAs from sea urchin embryos were used to probe a sea urchin genomic lambda library. Screening 10,000 phage by plaque hybridization yielded several hundred positive signals. With more stringent wash procedures, only two to three phage were positive. Three of these phage, one isolated by stringent wash procedures and two isolated by standard wash procedures were further investigated by restriction analysis, RNA gel blots, and DNA sequencing. The phage isolated by the stringent wash procedure appears to be a gene coding for the Specl mRNA. The other phage contain only partial homology to pSpec1 and pSpec2, 150 to 200 base pairs of the 3' untranslated region of the Spec1 and Spec2 mRNAs. It is concluded that the Spec1 and Spec2 mRNAs contain a highly repetitive element near their 3' end. The element is present at 2000 to 3000 copies per genome and may be transcribed at some sites other than those coding for the Spec1 and Spec2 genes. The possible function and evolutionary origin of the repetitive element is discussed

Preclinical Evaluation of ⁶⁸Ga-labeled RGD Peptide for Detection of Malignant Angiogenesis

Introduction. The early detection of tumor growth remains one of the most important tasks of diagnostic nuclear medicine. The vascular growth being created malignant neoplasms is a good target for the purpose. The molecular participants in the process are gallium-68 labeled vector to the delivery of radionuclides and positron-emission tomography (PET) imaging.Aim. Possibility researching of using the complex gallium-68 labeled peptide sequence RGD for PET imaging of tumor with different grade of neovascularization.Materials and methods. Complex compound of Ga-68 with the peptide NODAGA-cRGD2 (the proposed name used below is «Vascular, 68Ga») was used for studying of the distribution in mice with transplanted heterotopic xenografts of glioblastoma U-87 MG and breast adenocarcinoma Ca-755 after intravenous injection, as well as the possibility of visualization the tumor.Results and discussion. The «Vascular, 68Ga» biodistribution in the mice body is usual of laboratory animals is usual of the behavior of peptides in vivo: rapid clearance from the blood, intense urinary excretion. The accumulation of the drug in the area of glioblastoma in mice is on average 2 times higher than that in adenocarcinoma. The results of in vivo PET imaging of experimental tumor lesions correlate well with ex vivo radiometry data. Conclusion. The «Vascular, 68Ga» actively accumulated in well-vascularized tumor foci after intravenous injection and rapidly excreted from the body through the kidneys without noticeable non-specific accumulation in other organs and tissues. The PET imaging possibility of experimental tumor foci was shown