CloudMC: a cloud computing application for Monte Carlo simulation.

This work presents CloudMC, a cloud computing application-developed in Windows Azure®, the platform of the Microsoft® cloud-for the parallelization of Monte Carlo simulations in a dynamic virtual cluster. CloudMC is a web application designed to be independent of the Monte Carlo code in which the simulations are based-the simulations just need to be of the form: input files → executable → output files. To study the performance of CloudMC in Windows Azure®, Monte Carlo simulations with penelope were performed on different instance (virtual machine) sizes, and for different number of instances. The instance size was found to have no effect on the simulation runtime. It was also found that the decrease in time with the number of instances followed Amdahl's law, with a slight deviation due to the increase in the fraction of non-parallelizable time with increasing number of instances. A simulation that would have required 30 h of CPU on a single instance was completed in 48.6 min when executed on 64 instances in parallel (speedup of 37 ×). Furthermore, the use of cloud computing for parallel computing offers some advantages over conventional clusters: high accessibility, scalability and pay per usage. Therefore, it is strongly believed that cloud computing will play an important role in making Monte Carlo dose calculation a reality in future clinical practice.

[Role of cyclic AMP in gastric secretion. The secretion and mechanism of action of gastrin]. / Le rôle de l'AMP cyclique dans la sécrétion gastrique. Sécrétion et mécanisme d'action de la gastrine.

The present study involved evaluation of the role played by cyclic AMP on the secretion and mechanism of action of gastrin in man. On the basis of the results obtained, gastrin secretion induced by an excessive rise in gastric pH is accompanied by a simultaneous increase in plasma cyclic AMP concentrations (p less than 0.05) as well as a tissue cyclic AMP in the region of the fundus (p less than 0.001). By contrast, no significant change was seen regarding antropyloric AMP. As a result, it is felt that cyclic AMP does not play a direct role in the secretion of gastrin by G cells but is a mediator of the mechanism of action of gastrin in terms of the secretion of HCl by the parietal cell.

Deoxycytidylate deaminase in the diagnosis of acute myocardial infarction.

The diagnostic value of deoxycytidylate deaminase (dCMP) in the diagnosis of acute myocardial infarction (AMI) was examined in 31 healthy controls and 32 patients with proven AMI. Its specificity in normal controls was 93.5%. Its highest levels were measured on the 3rd to 5th post-infarct day, when its sensitivity reached 97.5%. Its diagnostic performance was similar to that of SGOT, total LDH1/LDH2 ratio greater than 1, total CPK and CPK-MB. Its peak levels showed a highly significant correlation (p less than 0.001) with those of the above enzymes. The measurement of dCMP may be a valuable complement in the diagnosis of AMI since this enzyme is not affected by lung infarction or hemolysis. Moreover, since it expresses tissue regeneration rather than destruction it may aid in the assessment of various interventions designed for the promotion of myocardial healing process.

[Secretion of gastric acid, gastrin and cyclic nucleotides in relation to the action of the vagus nerve]. / La sécrétion de l'acide gastrique, de la gastrine et des nucléotides cycliques en rapport avec l'action du nerf vague.

Changes on levels gastric acidity, on serum gastrin, cAMP and cGMP levels were studied in 18 healthy volunteers after either stimulation (injection of 0.2 IU of soluble insulin/kg body weight to a group of 9 subjects) or stimulation and inhibition (injection of insulin plus atropine per os to the other group of 9 subjects) of the vagus nerve. After vagus nerve stimulation, gastric acid levels, serum gastrin and cGMP were raised and cAMP reduced. After stimulation and inhibition of vagus nerve, gastrin and cAMP were increased, cGMP reduced and gastric acid levels remained unchanged. These findings suggest that the vagus nerve, and more particularly the acetylcholine released from its metaganglionic fibers, stimulate parietal cells provoking acid secretion, and also stimulate G cells with subsequent gastrin secretion through cGMP.

Levels of erythrocyte 2,3 DPG and ATP in heavy hashish smokers.

The variations in concentration of ATP and 2,3 DPG, and in lactic acid production as a function of time, were measured in the erythrocytes of heavy smokers. Results indicate that the most remarkable reduction in concentration of the compounds examined occurred at 30 and 45 min after hashish smoking. The findings are discussed in connection with the possible influence of hashish components, especially delta 9-THC, on the erythrocyte glycolytic pathway.

The significance of lymphocyte lipid changes after smoking hashish.

The increase of lymphocyte total lipids and phospholipids after smoking hashish, indicates either a lipid transfer from their site of production after smoking the drug or a mobilization of their biosynthetic mechanism in the lymphocyte. A fluctuation of individual phospholipid concentrations after "smoking" is related to the influence of certain hashish compounds on the various biosynthetic pathways of phospholipids in lymphocytes. Changes in phosphatidylcholine, phosphatidylinositol and phosphatidylserine are related to a possible fluctuation of the overall immune ability of the lymphocyte, by affecting the lymphocyte membrane enzyme mechanisms.

The possible effect of hashish on leukocytes and plasma lipids.

The possible fluctuation of leukocytes and plasma lipids, 30--60 min after smoking hashish, was studied. Total phospholipid content in both leukocytes and plasma was increased in a similar way to the total lipid content after smoking hashish. Differences in most of the phospholipid classes in leukocytes and plasma before and after smoking hashish were observed while the values in controls and chronic users of the drug before smoking hashish were found to be relatively close. Findings are discussed in relation to the pharmacological action of the drug on liver lipid metabolism.

Thin-layer chromatography of phospholipid components of normal and psoriatic epidermis.

The phospholipid pattern of human epidermis from 23 psoriatic patients and from 14 healthy individuals has been determined using lipid thin-layer chromatography. An increased amount of total phospholipids and statistically significant differences in some phospholipid components were found in psoriatic patients as compared to healthy controls. These abnormalities may be related to the altered architecture of the plasma membranes and their surface coats observed in psoriatic keratinocytes.

Erythrocyte 2,3-diphosphoglycerate as related to diabetes and obesity.

2,3-Diphosphoglycerate was determined in the erythrocytes of 17 diabetic and 18 obese patients. Results for obese subjects were significantly (P less than .01) different from those obtained for 21 healthy subjects. Results for obese and diabetic patients also differed significantly (P less than .01) but not those for diabetic and healthy subjects. Hemoglobin, hematocrit, or bicarbonate measurements did not differ among the three groups.