Initial Results From a CdTe High-Energy X-ray Detector on a TEM
Energy Dispersive X-ray analysis (EDX) in the transmission electron microscope (TEM) is a well-established technique for thin films. The higher accelerating voltage and small analysis volume allow experiments not be possible in the SEM. However, there are instances where characteristic X-rays from different elements are not resolvable using conventional Si based detectors. Detection of higher energy X-rays from these elements may circumvent the overlap issues. CdTe and CdZnTe detectors have been used for a number of years in nuclear and gamma-ray spectroscopy [1]. The energy response of a typical 1mm thick detector is shown in Figure 1 [2]. These experiments were intended to see if the ability of a CdTe X-ray detector to see higher energy photons would provide the ability to see and resolve high energy X-ray peaks in the TEM.
Kurchatov synchrotron radiation source: Status report
Abstract Project parameters of the big storage ring are practically reached. At the project energy of 2.5 GeV stored current reached 72 mA. Three SR beamlines are installed on the bending magnets of the small storage ring with an electron energy of 450 MeV. Three experimental stations are installed in VUV experimental hall. Three front ends of X-ray beamline are installed on the big storage ring. One X-ray beamline is out of biological shielding of the big ring. Construction of the big experimental hall is almost completed. A status report on the first part of the active proposals is given.
Nuclear sphingolipid metabolism.
Nuclear lipid metabolism is implicated in various processes, including transcription, splicing, and DNA repair. Sphingolipids play roles in numerous cellular functions, and an emerging body of literature has identified roles for these lipid mediators in distinct nuclear processes. Different sphingolipid species are localized in various subnuclear domains, including chromatin, the nuclear matrix, and the nuclear envelope, where sphingolipids exert specific regulatory and structural functions. Sphingomyelin, the most abundant nuclear sphingolipid, plays both structural and regulatory roles in chromatin assembly and dynamics in addition to being an integral component of the nuclear matrix. Sphingosine-1-phosphate modulates histone acetylation, sphingosine is a ligand for steroidogenic factor 1, and nuclear accumulation of ceramide has been implicated in apoptosis. Finally, nuclear membrane-associated ganglioside GM1 plays a pivotal role in Ca(2+) homeostasis. This review highlights research on the factors that control nuclear sphingolipid metabolism and summarizes the roles of these lipids in various nuclear processes.