Intercomparison of dose enhancement ratio and secondary electron spectra for gold nanoparticles irradiated by X-rays calculated using multiple Monte Carlo simulation codes.

PURPOSE: Targeted radiation therapy has seen an increased interest in the past decade. In vitro and in vivo experiments showed enhanced radiation doses due to gold nanoparticles (GNPs) to tumors in mice and demonstrated a high potential for clinical application. However, finding a functionalized molecular formulation for actively targeting GNPs in tumor cells is challenging. Furthermore, the enhanced energy deposition by secondary electrons around GNPs, particularly by short-ranged Auger electrons is difficult to measure. Computational models, such as Monte Carlo (MC) radiation transport codes, have been used to estimate the physical quantities and effects of GNPs. However, as these codes differ from one to another, the reliability of physical and dosimetric quantities needs to be established at cellular and molecular levels, so that the subsequent biological effects can be assessed quantitatively. METHODS: In this work, irradiation of single GNPs of 50 nm and 100 nm diameter by X-ray spectra generated by 50 and 100 peak kilovoltages was simulated for a defined geometry setup, by applying multiple MC codes in the EURADOS framework. RESULTS: The mean dose enhancement ratio of the first 10 nm-thick water shell around a 100 nm GNP ranges from 400 for 100 kVp X-rays to 600 for 50 kVp X-rays with large uncertainty factors up to 2.3. CONCLUSIONS: It is concluded that the absolute dose enhancement effects have large uncertainties and need an inter-code intercomparison for a high quality assurance; relative properties may be a better measure until more experimental data is available to constrain the models.

New flow-through analytical system based on ion-selective field effect transistors with optimised calcium selective photocurable membrane for bovine serum analysis.

An analytical system based on ion-selective field effect transistors (ISFETs) with Ca(2+) ion selective photocurable membranes is developed to offer a semiautomatic analysis of serum calcium concentration of ruminants. Optimisation of ion-sensitive membrane composition containing different copolymerised plasticizers was performed to minimise the effect of a highly lipophilic samples on sensors characteristics. To improve the system reliability the set of calibration solutions and measurement sequence were also optimised. The system was used to determine total calcium concentration in bovine sera. The precision of the ion determination was higher than reported for double charge ions with a standard deviation of about 3-7%. It is shown that the presence of coagulant in blood serum samples does not affect the determined total calcium concentration.

[Methodological approaches to forecasting of disability dynamics in Ukraine].

Estimated the dynamics of indexes of primary disability of adult and able to work population for 2000-2009 on the whole on Ukraine and on administrative territories. For development of the methodological going near prognostication of disability used the methods of mathematical statistics: analysis of sentinel rows and regressive analysis. Indexes over of disability during ten years are brought as sentinel rows through the system of sentinel parameters and supervision; the models of linear trends are built, their adequacy and authenticity are tested, a prognosis is certain. Creation of the improved methods of analysis gives an opportunity to extract regions which it is necessary in, first of all, to study reasons and problems of increase of disability; to work out the purposeful measures of warning of her increase.

Recent trends in potentiometric sensor arrays--a review.

Nowadays there exists a large variety of ion sensors based on polymeric or solid-state membranes that can be used in a sensor array format in many analytical applications. This review aims at providing a critical overview of the distinct approaches that were developed to build and use potentiometric sensor arrays based on different transduction principles, such as classical ion-selective electrodes (ISEs) with polymer or solid-state membranes, solid-contact electrodes (SCE) including coated wire electrodes (CWE), ion-sensitive field-effect transistors (ISFETs) and light addressable potentiometric sensors (LAPS). Analysing latest publications on potentiometric sensor arrays development and applications certain problems are outlined and trends are discussed.

Simple DFT model of clusters embedded in rare gas matrix: trapping sites and spectroscopic properties of Na embedded in Ar.

We present a theoretical model to study the dynamics of metallic clusters embedded in a rare gas matrix. We describe the active electrons of the embedded cluster using time dependent density functional theory, while the surrounding matrix is described in terms of classical molecular dynamics of polarizable atoms. The coupling between the cluster and the rare gas atoms is deduced from the work of Gross and Spiegelmann [J. Chem. Phys. 108, 4148 (1998)] and reformulated explicitly in a simple and efficient density functional form. The electron rare gas interaction takes the form of an averaged dipole fluctuation term, which retains the van der Waals long range interaction, and a short range repulsive pseudopotential, which accounts for the Pauli repulsion of the electron by the rare gas atom. We applied our model to Na clusters embedded in Ar matrix. For the latter we developed an efficient local pseudopotential, which allows studying systems containing more than 10(3) Ar atoms. We show that large systems are indeed necessary to account properly for long range polarization of the matrix, that competes with the matrix confinement effect. We focus our study on Na(2), Na(4), and Na(8). For each system, we have determined the geometry of the most favorable trapping site by means of damped molecular dynamics. We present the effect of matrix embedding on the optical absorption spectrum. For Na(2), the trapping site can be unambiguously identified by comparison of the absorption spectrum with experiment. For Na(4) the spectrum of the embedded cluster is significantly different from the free cluster spectrum, while for Na(8) differences are less pronounced.

[Methodology for the comprehensive evaluation of the quality of performance of activities of medical and social experts]. / Metodologiia kompleksnoi otsinky iakosti diaial'nosti ustanov mediko-sotsial'noi ekspertyzy.

The paper scientifically substantiates methodology, approaches, criteria, and control indices for assessment of activities of establishments of medical-and-social performance. Most indices for efficiency and certain indices for week points in the work of establishments of the service depend on interaction thereof with curative- and prophylactic institutions; the best results with the problem of prevention of disability and rehabilitation of invalids are supposed to be achieved through collaborative efforts. Other criteria and intermediate indices having an effect on the quality of activities reflect the resource- and trained personnel supplies of establishments of the service, amount of work, organizational measures designed to raise the quality of medical-and-social expert performance.

[Role of health personnel in reformation of the service of medical and social experts]. / Rol' haluzevoï nauky u reformuvanni sluzhby medyko-sotsial'noï ekspertyzy.

The article analyzes the present-day status of medical-and-social expert performance service delivery, those contingents of invalids on their care, with ways outlined for the service formation. Shown in the article is the role of sectorial science in the working out of theoretical and scientific-and-applied problems of reformation of the service organization, in carrying out medical-and-social expert evaluation and rehabilitation of invalids, validation of the legal and standard basis of the service reformation and optimization of management thereof.

[Dynamics of indices of peripheral circulation as one of the prognostic criteria in acute myocardial infarction]. / Dinamika pokazatelei perifericheskogo krovotoka kak odin iz prognosticheskikh kriteriev pri ostrom infarkte miokarda.

The results of our investigations demonstrate that significant differences exist in peripheral hemodynamics of patients with severe and more favourable course of acute myocardial infarction. This can be explained by different types of hemodynamics. Thus, such parameters as arterial inflow and venous outflow can serve prognostic factors of acute myocardial infarction.

[On possible prognostic values of anti-endotoxin immunological parameters in acute myocardial infarction]. / O vozmozhnom prognosticheskom znachenii pokazatelei anti-éndotoksinovogo immuniteta pri ostrom infarkte miokarda.

Endotoxin is a biologically active substance that has a lipopolysaccharide structure. It is found in the cell walls of microorganisms, principally gram-negative bacteria. By contacting with the cell, endotoxin enhances immunity. The findings suggest that acute myocardial infarction (AMI) occurs due to low immunity that remains the same at week 3 of the disease, thus the levels of antiendotoxin agents may be used in predicting AMI.

[Acute respiratory distress syndrome in endotoxic shock]. / Ostryi respiratornyi distress-sindrom pri éndotoksinovom shoke.

Large amounts of lipopolysaccharides released in blood after death of Gram-negative bacteria are responsible for endotoxinemia and endotoxic shock. Endotoxin is eliminated from the body via different routes including the lungs. One of the mechanisms of lipopolysaccharides transport to the lungs, which respond with acute distress syndrome, is their transfer by polymorphonuclear leukocytes.

[Central hemodynamics of patients during an attack of bronchial asthma]. / Tsentral'naia genodinamika u bol'nykh vo vremia pristupa bronkhial'noi astmy.

The authors presented the results of a combined study of 100 patients with infectious-allergic bronchial asthma. During and after attacks of asphyxia parameters of central hemodynamics and pressure in the lesser circulation system were defined. The patients were divided into 3 groups with relation to cardiac output values. An increase in cardiac output and pressure elevation in the right ventricle were noted in the 1st group, the values of pressure of pulmonary artery obstruction slightly raised. The absence of a marked increase in cardiac output was observed in the 2nd group, however pressure in the arterial system of the lesser circulation increased in the period of asphyxia. A decrease in cardiac output and an increase in pressure in the system of the pulmonary artery were noted in the patients of the 3rd group during asthmatic attacks. Such changes in the hemodynamics of the patients with bronchial asthma during attacks of asphyxia led to an idea of a possible favorable reaction of the cardiovascular system in the 1st group, maximum effort of compensatory capabilities in the 2nd group and depletion of reserve function of the cardiovascular system in the 3rd group. An elevation of pressure of pulmonary artery obstruction in the patients of the 2nd and 3rd groups confirmed a possibility of development not only of right but also left ventricular circulatory insufficiency during an attack of bronchial asthma.

[Physical work capacity prognosis of hypertensive patients]. / Prognozirovanie fizicheskoi rabotosposobnosti u bol'nykh gipertonicheskoi bolezn'iu.

From the results of the examination of 176 patients with hypertensive disease the authors compared 49 signs, including sex, age, the findings of medical history, inspection, X-ray, ECG and consultations of an ophthalmologist with the power of physical exertion on a bicycle ergometer. Fifteen signs with a marked correlative connection with the power of exertion (r greater than 0.5) were distinguished. Systolic arterial pressure (170 mm Hg and more), circulatory insufficiency, concomitant ischemic heart disease, atherosclerosis of the peripheral arteries and hypokinetic type of circulation proved to be the most important factors limiting the physical working capacity of patients with hypertensive disease. A table for prognosticating the working capacity was compiled.

[Effect of emotional stress on the contractile function of human heart (according to the echocardiographic data)]. / Vliianie émotsional'nogo napriazheniia na sokratitel'nuiu funktsiiu serdtsa cheloveka (po dannym ékhokardiografii).

Cardiac function was studied by echocardiography in 12 healthy sixth-year students at mid-semester, immediately before taking an exam and 30 minutes after it. It was found that the emotional stress experienced prior to the exam is attended with an increase in cardiac output by one and a half times and external work by two. This increase of the pump cardiac function is ensured without any essential increase in the diastolic dimensions of the left cardiac ventricle at the expense of fuller blood ejection from the left ventricle and decrease of its residual systolic volume. Since the students had taken more than 50 exams in the past and were adapted to the pre-examination situation, the circulatory changes revealed may be regarded as adaptive providing for the rich flow of blood to the brain.