Design of commissioning process for Halcyon™ linac with a new rigid board: A clinical experience

PurposeThis study performed the accurate measurements of beam profiles with a new rigid board, which was consistent with the supplied reference beam profiles (RBPs) for clinical Halcyon model.MethodsPercentage depth doses (PDDs), lateral and diagonal dose profiles were measured and compared with RBPs. A water tank was set on the rigid board bridged Halcyon bore without sagging and source-to-surface distance was 90.0 cm. Field sizes were from 2.0 to 28.0 cm squares and depths of lateral and diagonal dose profiles were 1.3, 5.0, 10.0, and 20.0 cm. For the PDD, the depth of maximum dose (d_max), PDD value at depth of 10.0 cm (PDD₁₀), and absolute dose difference (DD) between RBP and measured beam profiles (MBP) were evaluated. For lateral and diagonal dose profiles, DDs for the whole and divided areas (central, shoulder, and extended areas) defined by third derivative, and distance-to-agreement (DTA) in the penumbra area were evaluated.ResultsFor PDDs, the differences of d_max and PDD₁₀ and DD beyond the d_max were within 1.0 mm, 0.3%, and 1.0%, respectively. For lateral and diagonal dose profiles, the DDs reached approximately 5.0% in the whole area because of penumbra area, while the DDs in the central, shoulder, and extended areas were within 1.0%, 2.0%, and 1.0%, respectively. The DTAs in the penumbra area were within 0.8 mm.ConclusionsThe supplied RBPs can be used clinically owing to the good agreement with the accurate MBPs with rigid board.     

A method of estimating from two aligned present-day DNA sequences their ancestral composition and subsequent rates of substitution,possibly different in the two lineages,corrected for multiple and parallel substitutions at the same site

Summary The course of evolutionary change in DNA sequences has been modeled as a Markov process. The Markov process was represented by discrete time matrix methods. The parameters of the Markov transition matrices were estimated by least-squares direct-search optimization of the fit of the calculated divergence matrix to that observed for two aligned sequences. The Markov process corrected for multiple and parallel substitutions of bases at the same site. The method avoided the incorrect assumption of all previously described methods that the divergence between two present-day sequences is twice the divergence of either from the common and unknown ancestral sequence. The three previous methods were shown to be equivalent. The present method also avoided the undesirable assumptions that sequence composition has not changed with time and that the substitution rates in the two descendant lineages were the same. It permitted simultaneous estimation of ancestral sequence composition and, if applicable, of different substitution rates for the two descendant lineages, provided the total number of estimated parameters was less than 16. Properties of the Markov chain were discussed. It was proved for symmetric substitution matrices that all elements of the equilibrium divergence matrix equal 1/16, and that the total difference in the divergence matrix at epoch k equals the total change in the common substitution matrix at epoch 2k for all values of k. It was shown how to resolve an ambiguity in the assignment of two different substitution rates to the two descendant lineages when four or more similar sequences are available. The method was applied to the divergence matrix for codon site 3 for the mouse and rabbit beta-globins. This observed divergence matrix was significantly asymmetric and required at least two different substitution rates. This result could be achieved only by using different asymmetric substitution matrices for the two lineages.     

Statistical Inference for a Gibbs Point Process of Mutually Non-Intersecting Discs

For a Gibbs point process of mutually non-intersecting discs a parameter estimation method is suggested. It is applied to a pattern of positions of beadlet anemones, for which, until now, no appropriate Gibbs process model has been found.     

Moments of physiological transit time distributions and the time course of drug disposition in the body

Characterizing the tissue distribution kinetics of drugs by physiological and physico-chemical parameters and using a circulatory model the time course of blood concentration after intravenous injection is predicted for linear pharmacokinetic systems. The interrelationships between the first three (zero to second) moments of the distribution functions of organ transfer times, circulation times and residence times of drug molecules in the body are described. Utilizing literature data the model is applied to the analysis of lidocain kinetics in humans.     

手术室工作流程现状分析

目的 通过具体的手术室流程分析，探索医院手术室流程科学合理的管理方法。方法 运用现场调研法对手术室的流程进行考察分析，并应用流程图的方法显化现有手术室的流程，对现有流程采用德尔菲法和FTA的方法进行分析。结果 得到手术室工作流程的问题报告。结论 手术室的流程问题主要有：等待浪费，沟通失效，操作行为不当，管理技术不当，设施布局不合理。     

Quantification and Proteomic Characterization of β-Hydroxybutyrylation Modification in the Hearts of AMPKα2 Knockout Mice

AMP-activated protein kinase alpha 2 (AMPKα2) regulates energy metabolism, protein synthesis, and glucolipid metabolism myocardial cells. Ketone bodies produced by fatty acid β-oxidation, especially β-hydroxybutyrate, are fatty energy–supplying substances for the heart, brain, and other organs during fasting and long-term exercise. They also regulate metabolic signaling for multiple cellular functions. Lysine β-hydroxybutyrylation (Kbhb) is a β-hydroxybutyrate–mediated protein posttranslational modification. Histone Kbhb has been identified in yeast, mouse, and human cells. However, whether AMPK regulates protein Kbhb is yet unclear. Hence, the present study explored the changes in proteomics and Kbhb modification omics in the hearts of AMPKα2 knockout mice using a comprehensive quantitative proteomic analysis. Based on mass spectrometry (LC-MS/MS) analysis, the number of 1181 Kbhb modified sites in 455 proteins were quantified between AMPKα2 knockout mice and wildtype mice; 244 Kbhb sites in 142 proteins decreased or increased after AMPKα2 knockout (fold change >1.5 or <1/1.5, p < 0.05). The regulation of Kbhb sites in 26 key enzymes of fatty acid degradation and tricarboxylic acid cycle was noted in AMPKα2 knockout mouse cardiomyocytes. These findings, for the first time, identified proteomic features and Kbhb modification of cardiomyocytes after AMPKα2 knockout, suggesting that AMPKα2 regulates energy metabolism by modifying protein Kbhb.     

Study on the role of calmodulin in sperm function through the enrichment and identification of calmodulin-binding proteins in bovine ejaculated spermatozoa

Calmodulin is a small, highly conserved acidic protein present at high levels in spermatozoa that mediates numerous intracellular Ca²⁺-dependent events. Sperm motility and fertilizing ability results from an array of biochemical pathways under Ca²⁺ control, in which the importance of calmodulin is not fully understood. The role of calmodulin in sperm function has been mostly assessed using antagonists. Nevertheless, few known calmodulin-regulated enzymes have been described in spermatozoa regarding their involvement in sperm function. To further understand the role of this important Ca²⁺ mediator in spermatozoa, different studies were also undertaken to investigate and to identify sperm calmodulin-binding proteins and determine their localization and subcellular distribution as an attempt to elucidate the role of this important Ca²⁺ mediator. In the present study, sperm calmodulin-binding proteins were identified by mass spectrometry after Ca²⁺-dependent biotinylated-calmodulin binding on sperm head proteins subjected to 2D electrophoresis and transferred on a polyvinylidene difluoride membrane. Calmodulin binding protein identification was also done on detergent extracted whole sperm proteins pulled down in a Ca²⁺-dependent manner by calmodulin-conjugated sepharose beads. In this latter group, 300 proteins were identified in at least two experiments out of three, and those identified in the three independent experiments were analyzed for overrepresented biological processes using the Bos taurus Gene Ontology database. Proteins with known function in reproductive processes, fertilization, sperm-egg recognition, sperm binding to the zona pellucida, regulation of sperm capacitation, and sperm motility were identified and further emphasize the importance of calmodulin in sperm function.