A spectroscopic study of the cycling transition 4s[3/2]_2-4p[5/2]_3 at 811.8 nm in Ar-39: Hyperfine structure and isotope shift

Doppler-free saturated absorption spectroscopy is performed on an enriched radioactive Ar-39 sample. The spectrum of the 3s^2 3p^5 4s [3/2]_2 - 3s^2 3p^5 4p [5/2]_3 cycling transition at 811.8 nm is recorded, and its isotope shift between Ar-39 and Ar-40 is derived. The hyperfine coupling constants A and B for both the 4s [3/2]_2 and 4p [5/2]_3 energy levels in Ar-39 are also determined. The results partially disagree with a recently published measurement of the same transition. Based on earlier measurements as well as the current work, the isotope shift and hyperfine structure of the corresponding transition in Ar-37 are also calculated. These spectroscopic data are essential for the realization of laser trapping and cooling of Ar-37 and Ar-39

Developments in PF-HPLC (pneumatic-fluoropolymer high performance liquid chromatography)

Return missions are providing unique opportunities to deepen our knowledge of the formation and evolution of the solar system. The six Apollo missions have been critical in shaping our understanding of the Earth-Moon history [1], and the recent Genesis (solar wind; e.g., [2]), Stardust (cometary dust from Wild 2; e.g., [3,4]) and Hayabusa (dust from S-type asteroid from Itokawa; e.g., [5]) missions brought in a wealth of data

The REE isotopic compositions of the Earth

Lanthanides are a group of 14 naturally occurring elements with atomic numbers ranging from 57 (La) to 74 (Lu), which are also known as rare earth elements (REE). REEs are ubiquitous in minerals and rocks. The chemical properties of REEs vary as smooth functions of their atomic numbers, a phenomenon known as the contraction of the lanthanides. This is the main control behind REE fractionation in minerals and rocks. The relative abundance of REEs is usually presented as the REE pattern by normalizing the concentrations in the sample to those in reference materials such as chondrites and shales

Spectroscopic study of the cycling transition 4s[3/2]2-4p[5/2] 3 at 811.8 nm in Ar39: Hyperfine structure and isotope shift

Doppler-free saturated absorption spectroscopy is performed on an enriched radioactive Ar39 sample. The spectrum of the 3s23p54s[3/2]2- 3s23p54p[5/2]3 cycling transition at 811.8 nm is recorded, and its isotope shift between Ar39 and Ar40 is derived. The hyperfine coupling constants A and B for both the 4s[3/2]2 and 4p[5/2]3 energy levels in Ar39 are also determined. The results partially disagree with a recently published measurement of the same transition. Based on earlier measurements as well as the current work, the isotope shift and hyperfine structure of the corresponding transition in Ar37 are also calculated. These spectroscopic data are essential for the realization of laser trapping and cooling of Ar37,39. © 2011 American Physical Society

The Skandapurāṇa Volume V: Adhyāyas 96 – 112. The Varāha Cycle and the Andhaka Cycle Continued

bookAsian Studie

Defining the baseline of the REE stable isotope variations in solar system materials: Earth

Mass-dependent fractionations (MDFs) of stable isotopes record critical information regarding the origin and evolution of planetary materials [1]. Studies of MDF of refractory lithophile elements (RLEs) can provide insights into condensation/evaporation and planetary accretion processes in the early solar system. For example, the lighter calcium isotope composition observed in carbonaceous meteorites compared to that of the bulk silicate Earth, enstatite and ordinary chondrites [2, 3] may be due to the contribution of refractory dust [4, 5], which has a light Ca isotope composition [6, 7]. In contrast, titanium, another RLE with a similar chemical behavior in the early solar system, was found to have uniform isotope compositions among different groups of meteorites including carbonaceous chondrites [8]. A potential explanation for the dichotomy of these two refractory elements could be connected to the higher 50% condensation temperature of Ti relative to Ca [9]. The isotopic results suggest that no Ti net loss took place from the CAI-forming region, while not all Ca condensed in the CAIs [7, 8]. Clearly, more proxies are needed to better understand the processes that occurred during the condensation of the solar nebula

The REE isotopic compositions of the Earth

Lanthanides are a group of 14 naturally occurring elements with atomic numbers ranging from 57 (La) to 74 (Lu), which are also known as rare earth elements (REE). REEs are ubiquitous in minerals and rocks. The chemical properties of REEs vary as smooth functions of their atomic numbers, a phenomenon known as the contraction of the lanthanides. This is the main control behind REE fractionation in minerals and rocks. The relative abundance of REEs is usually presented as the REE pattern by normalizing the concentrations in the sample to those in reference materials such as chondrites and shales

Developments in PF-HPLC (pneumatic-fluoropolymer high performance liquid chromatography)

Return missions are providing unique opportunities to deepen our knowledge of the formation and evolution of the solar system. The six Apollo missions have been critical in shaping our understanding of the Earth-Moon history [1], and the recent Genesis (solar wind; e.g., [2]), Stardust (cometary dust from Wild 2; e.g., [3,4]) and Hayabusa (dust from S-type asteroid from Itokawa; e.g., [5]) missions brought in a wealth of data

An evaluation tool for FKBP12-dependent and -independent mTOR inhibitors using a combination of FKBP-mTOR fusion protein, DSC and NMR

Mammalian target of rapamycin (mTOR), a large multidomain protein kinase, regulates cell growth and metabolism in response to environmental signals. The FKBP rapamycin-binding (FRB) domain of mTOR is a validated therapeutic target for the development of immunosuppressant and anticancer drugs but is labile and insoluble. Here we designed a fusion protein between FKBP12 and the FRB domain of mTOR. The fusion protein was successfully expressed in Escherichia coli as a soluble form, and was purified by a simple two-step chromatographic procedure. The fusion protein exhibited increased solubility and stability compared with the isolated FRB domain, and facilitated the analysis of rapamycin and FK506 binding using differential scanning calorimetry (DSC) and solution nuclear magnetic resonance (NMR). DSC enabled the rapid observation of protein–drug interactions at the domain level, while NMR gave insights into the protein–drug interactions at the residue level. The use of the FKBP12–FRB fusion protein combined with DSC and NMR provides a useful tool for the efficient screening of FKBP12-dependent as well as -independent inhibitors of the mTOR FRB domain