Evaluation of SrAl O :Eu, Dy phosphor for potential applications in thermoluminescent dosimetry.

Purpose: To evaluate the use of commercial-grade strontium aluminate phosphorescent powder as a thermoluminescent (TL) dosimeter for clinical radiotherapy beams.

Materials And Method: Commercially available Eu , Dy co-doped strontium aluminate powder (SrAl O :Eu, Dy) was annealed and then irradiated using 20 × 20 cm field size, with 6-MV (PDD  = 70.7) and 18-MV (PDD  = 79.

Cumulative Doses to Brain and Other Critical Structures After Multisession Gamma Knife Stereotactic Radiosurgery for Treatment of Multiple Metastatic Tumors.

Purpose: Repeat stereotactic radiosurgery (SRS) is an attractive alternative to whole brain radiation therapy (WBRT) for treatment of recurrent brain metastases (BM). The purpose of this study is to determine the cumulative doses to the brain and critical normal structures in patients who underwent repeat courses of Gamma Knife (GK) SRS.

Materials And Methods: We retrospectively identified ten patients who received at least three GK-SRS sessions for multiply recurrent BM at our institution from 2013 to 2016.

Influence of montmorillonite on nucleotide oligomerization reactions: a molecular dynamics study.

We investigate a proposed origins of life scenario involving the clay montmorillonite and its catalytic role in forming oligonucleotides from activated mononucleotides. Clay and mineral surfaces are important for concentrating the reactants and for promoting nucleotide polymerization reactions. Using classical molecular dynamics methods we provide atomic details of reactant conformations prior to polynucleotide formation, lending insight into previously reported experimental observations of this phenomenon.

On the physical basis of the amino acid polar requirement.

Understanding how codons became associated with their specific amino acids is fundamental to deriving a theory for the origin of the genetic code. Carl Woese and coworkers designed a series of experiments to test associations between amino acids and nucleobases that may have played a role in establishing the genetic code. Through these experiments it was found that a property of amino acids called the polar requirement (PR) is correlated with the organization of the codon table.