randomizeR: An R Package for the Assessment and Implementation of Randomization in Clinical Trials

Randomization in clinical trials is the key design technique to ensure the comparability of treatment groups. Although there exist a large number of software products which assist the researcher to implement randomization, no tool which would cover a wide range of procedures and allow the comparative evaluation of the procedures under practical restrictions has been proposed in the literature so far. The R package randomizeR addresses this need. The paper includes a detailed description of the randomizeR package that serves as a tutorial for the generation of randomization sequences and the assessment of randomization procedures

ERDO - a framework to select an appropriate randomization procedure for clinical trials

Background: Randomization is considered to be a key feature to protect against bias in randomized clinical trials. Randomization induces comparability with respect to known and unknown covariates, mitigates selection bias, and provides a basis for inference. Although various randomization procedures have been proposed, no single procedure performs uniformly best. In the design phase of a clinical trial, the scientist has to decide which randomization procedure to use, taking into account the practical setting of the trial with respect to the potential of bias. Less emphasis has been placed on this important design decision than on analysis, and less support has been available to guide the scientist in making this decision.Methods: We propose a framework that weights the properties of the randomization procedure with respect to practical needs of the research question to be answered by the clinical trial. In particular, the framework assesses the impact of chronological and selection bias on the probability of a type I error. The framework is applied to a case study with a 2-arm parallel group, single center randomized clinical trial with continuous endpoint, with no-interim analysis, 1:1 allocation and no adaptation in the randomization process.Results: In so doing, we derive scientific arguments for the selection of an appropriate randomization procedure and develop a template which is illustrated in parallel by a case study. Possible extensions are discussed.Conclusion: The proposed ERDO framework guides the investigator through a template for the choice of a randomization procedure, and provides easy to use tools for the assessment. The barriers for the thorough reporting and assessment of randomization procedures could be further reduced in the future when regulators and pharmaceutical companies employ similar, standardized frameworks for the choice of a randomization procedure

Проектирование технологического процесса изготовления кассеты экструдера

Выпускная квалификационная работа по направлению 15.03.01 "Технология, оборудование и автоматизация машиностроительных производств". Данная работа заключается в разработке технологического процесса изготовления детали "Кассета экструдера". В состав работы входят части: технологическая; конструкторская; финансовый менеджмент, ресурсоэффективность и ресурсосбережение; социальная ответственность.Final qualification work in the direction of 15.03.01 "Technology, equipment and automation of machine-building industries". This work consists in the development of the technological process of manufacturing the part "Extruder cassette". The work includes the following parts: technological; design; financial management, resource efficiency and resource conservation; social responsibility

Гидроимпульсный силовой механизм сваебойной машины в условиях обустройства месторождений

AbstractObjectivesThis study sought to evaluate whether objective assessment of the myocardial functional reserve, using strain rate imaging (SRI), allows accurate detection of viable myocardium.BackgroundStrain rate imaging is a new echocardiographic modality that allows quantitative assessment of segmental myocardial contractility.MethodsIn 37 patients (age 58 ± 9 years) with ischemic left ventricular dysfunction, myocardial viability was assessed using low-dose (10 μg/kg body weight per min) two-dimensional dobutamine stress echocardiography (DSE), tissue Doppler imaging, SRI and 18F-fluorodeoxyglucose (18FDG) positron emission tomography (PET). The peak systolic tissue Doppler velocity and peak systolic myocardial strain rate were determined at baseline and during low-dose dobutamine stress from the apical views.ResultsA total of 192 segments with dyssynergy at rest were classified by 18FDG PET as viable in 94 and nonviable in 98. An increase of peak systolic strain rate from rest to dobutamine stimulation by more than −0.23 1/s allowed accurate discrimination of viable from nonviable myocardium, as determined by 18FDG PET with a sensitivity of 83% and a specificity of 84%. Receiver operating characteristic (ROC) curve analysis showed an area under the curve for prediction of nonviable myocardium, as determined by 18FDG PET using SRI, of 0.89 (95% confidence interval [CI] 0.88 to 0.90), whereas the area under the ROC curve using tissue Doppler imaging was 0.63 (95% CI 0.61 to 0.65).ConclusionsThe increase in the peak systolic strain rate during low-dose dobutamine stimulation allows accurate discrimination between different myocardial viability states. Strain rate imaging is superior to two-dimensional DSE and tissue Doppler imaging for the assessment of myocardial viability

Photocatalytic generation of hydrogen using iron-containing metal-ceramic composites with simultaneous degradation of organic compounds

The phase composition of composites was investigated, which were received by nitriding the ferroboron and ferrosilicoaluminium by the SHS method and modified with additives of schungite and titanium. Photocatalytic activity of composites in combined processes of hydrogen generation and degradation of organic substances was investigated. The activity of composites is related to the presence of a phase of metallic iron in their composition, concentration in the system of activator reagents (Н[2]О[2], Н[2]С[2]О[4]), and also with the presence of high energy-gap semiconductor in the composite matrix

Исследование влияния параметров режима лазерной сварки на геометрические размеры шва

Существенную роль в обеспечении надежности тепловыделяющих сборок играют сварные соединения, эксплуатационные свойства которых во многом определяются наличием в сварном шве и зоне термического влияния загрязнений, остаточных напряжений и закалочных структур. Цирконий является основным конструкционным материалом для активных зон ядерных реакторов. В настоящей работе предложена технология лазерной сварки пластин толщиной 0,5 мм из циркониевого сплава Э110, проведены теоретические расчеты режимов сварки и выбор сварочного оборудования.Welds play an important role in ensuring the reliability of fuel assemblies. Their performance properties are determined by the presence of contaminants, residual stresses and quenching structures in the weld and the heat-affected zone. Zirconium is the main structural material for the manufacture of nuclear reactor cores. The technology of laser welding of 0,5 mm thick plates from zirconium alloy E110 is offered in this work, theoretical calculations of welding modes and choice of welding equipment are carried out

Превентивная сущность промышленного дизайна в современном образовании и обществе

The article is devoted to Future design - modern prognostic directions of design activity. The article evaluates the prospects of introducing methods of technological forecasting in the curriculum of industrial design. We present here the list of relevant topics for lectures of the subject