Design and optimization of a 100 keV DC/RF ultracold electron source

An ultracold electron source based on near-threshold photoionization of a laser-cooled and trapped atomic gas is presented in this work. Initial DC acceleration to 10 keV and subsequent acceleration of the created bunches to 100 keV by RF fields makes the design suitable to serve as injector for accelerator-based light sources, single-shot ultrafast protein crystallography, applications in dielectric laser acceleration schemes, and potentially as an injector for free electron lasers operating in the quantum regime. This paper presents the design and properties of the developed DC/RF structure. It is shown that operation at a repetition frequency of 1 kHz is achievable and detailed particle tracking simulations are presented showing the possibility of achieving a brightness that can exceed conventional RF photosources

The use of strontium as a marker of calcium in the studies of bone mineralization

The Ca-Sr substitution in bone is investigated using the animal model. Experimental and control groups are compared with respect to elemental composition, both determine at organ and cell levels and structure of the minerals. It is found that the applied doses of strontium (maximum 438 mg Sr/kg body weight) do not disturb the course of remodelling of the mature bone as well as formation of the young bone. The amount of Sr deposited in bone is independent of the route of administration (intravascular, intraperitoneal, intramuscular). The distribution of the Sr concentration in bone of mature animals reveals a characteristic pattern. The bulk of the strontium is distributed homogenously in bone. At places where bone remodelling is in progress, an elevated Sr concentration is observed. The localization of places of larger Sr concentration in bone is impossible without prior oxytetracycline labelling. The massive deposition of Sr in bone is detected during the growth of the skeleton. The possibility of in vivo measurements of Sr concentrations using low-power X-ray tube is demonstrated. The applications of Sr as a marker of calcium in the studies of human bone mineralization are discussed

The use of strontium as a marker of calcium in the studies of bone mineralization

The Ca-Sr substitution in bone is investigated using the animal model. Experimental and control groups are compared with respect to elemental composition, both determine at organ and cell levels and structure of the minerals. It is found that the applied doses of strontium (maximum 438 mg Sr/kg body weight) do not disturb the course of remodelling of the mature bone as well as formation of the young bone. The amount of Sr deposited in bone is independent of the route of administration (intravascular, intraperitoneal, intramuscular). The distribution of the Sr concentration in bone of mature animals reveals a characteristic pattern. The bulk of the strontium is distributed homogenously in bone. At places where bone remodelling is in progress, an elevated Sr concentration is observed. The localization of places of larger Sr concentration in bone is impossible without prior oxytetracycline labelling. The massive deposition of Sr in bone is detected during the growth of the skeleton. The possibility of in vivo measurements of Sr concentrations using low-power X-ray tube is demonstrated. The applications of Sr as a marker of calcium in the studies of human bone mineralization are discussed.</p

Microcalcifications in Early Intimal Lesions of Atherosclerotic Human Coronary Arteries

Although calcium (Ca) precipitation may play a pathogenic role in atherosclerosis, information on temporal patterns of microcalcifications in human coronary arteries, their relation to expression of calcification-regulating proteins, and colocalization with iron (Fe) and zinc (Zn) is scarce. Human coronary arteries were analyzed post mortem with a proton microprobe for element concentrations and stained (immuno)histochemically for morphological and calcification-regulating proteins. Microcalcifications were occasionally observed in preatheroma type I atherosclerotic intimal lesions. Their abundance increased in type II, III, and IV lesions. Moreover, their appearance preceded increased expression of calcification-regulating proteins, such as osteocalcin and bone morphogenetic protein-2. In contrast, their presence coincided with increased expression of uncarboxylated matrix Gla protein (MGP), whereas the content of carboxylated MGP was increased in type III and IV lesions, indicating delayed posttranslational conversion of biologically inactive into active MGP. Ca/phosphorus ratios of the microcalcifications varied from 1.6 to 3.0, including amorphous Ca phosphates. Approximately 75% of microcalcifications colocalized with the accumulation of Fe and Zn. We conclude that Ca microprecipitation occurs in the early stages of atherosclerosis, inferring a pathogenic role in the sequel of events, resulting in overt atherosclerotic lesions. Microcalcifications may be caused by local events triggering the precipitation of Ca rather than by increased expression of calcification-regulating proteins. The high degree of colocalization with Fe and Zn suggests a mutual relationship between these trace elements and early deposition of Ca salts