Inactivation of Spores and Vegetative Forms of Clostridioides Difficile by Chemical Biocides: Mechanisms of Biocidal Activity, Methods of Evaluation, and Environmental Aspects

Clostridioides difficile infections (CDIs) are the most common cause of acquired diseases in hospitalized patients. Effective surface disinfection, focused on the inactivation of the spores of this pathogen, is a decisive factor in reducing the number of nosocomial cases of CDI infections. An efficient disinfection procedure is the result of both the properties of the biocidal agent used and the technology of its implementation as well as a reliable, experimental methodology for assessing the activity of the biocidal active substance based on laboratory models that adequately represent real clinical conditions. This study reviews the state of knowledge regarding the properties and biochemical basis of the action mechanisms of sporicidal substances, with emphasis on chlorine dioxide (ClO2). Among the analyzed biocides, in addition to ClO2, active chlorine, hydrogen peroxide, peracetic acid, and glutaraldehyde were characterized. Due to the relatively high sporicidal effectiveness and effective control of bacterial biofilm, as well as safety in a health and environmental context, the use of ClO2 is an attractive alternative in the control of nosocomial infections of CD etiology. In terms of the methods of assessing the biocidal effectiveness, suspension and carrier standards are discussed.

R&D of the PERT basic model for project planning

The guiding principles of project implementation are planning. The discrepancy in time, cost, and quality between the plan and the actual implementation of the project requires management decisions supported by an analysis of the optimization of the duration of the project and the search for reserves to reduce the implementation time. For this purpose, a basic PERT model for a specific project was developed, early and late deadlines for work, time reserves, and a critical path were calculated. This work is aimed at applying methods of evaluation and analysis of projects to find optimal solutions and control the efficiency of time and costs in project planning, by varying the work on the project and the executors of the work. The results of this study showed that there are quite large time reserves for works 5-7, 7-9, 6-9, etc., which makes it possible to redistribute work between performers and allows you to vary performers during the implementation of several projects simultaneously.

Modern approaches to rehabilitation of patients using removable laminar dentures

The demand for dental orthopedic assistance in Russia makes more than 60% of the number of examined patients. With this, a share of use of removable dentures for rehabilitation of patients with partial or complete absence of teeth makes 40.2% of all types of prosthetics. Removable prosthetics remains an actual treatment option for patients with partial or complete absence of dentitions, along with use of non-removable structures including those with support on dental implants. Improvement of approaches to manufacture and design of dentures led to a considerable increase in the variants of combinations of materials and methods of their manufacture, and there appeared a possibility to optimize denture structures due to the ability to compensate for atrophic processes of the bone tissue. All this permits an orthopedist to achieve satisfactory results in treatment with use of removable dentures. In the given literature review, modern views on the variants of orthopedic rehabilitation of patients with use of removable laminar dentures are presented including their technological, functional, operational, phonetic, chewing peculiarities, and information on modern materials for manufacture of dentures is given. Based on the literature data, it can be concluded that despite active development of the technological component of the manufacture of removable dentures, the basic principles of their design, methods of evaluation of the effectiveness and comfort of use have not undergone significant changes. However, there are a significant number of factors whose influence on the success of orthopedic rehabilitation with removable dentures has not been fully studied. For example, orthopedic dentists often do not analyze the volume of atrophy of the bone tissue of the jaws and design the basis of a dental prosthesis without taking these parameters into account. Another important issue that remains not considered is taking into account the design and architectonics of the resulting prosthesis and its effect on the speed and direction of respiratory flows in the oral cavity. All this creates a technological window that allows, due to compliance with the physiological requirements of the factors described above, to significantly increase the functional properties of the denture, to facilitate the patients habituation to the prosthesis by reducing the adaptation period. The research conducted in this area of knowledge will permit to obtain both new scientific data and develop a number of practical recommendations aimed at improvement of the quality of orthopedic rehabilitation using removable dentures made of various materials.

Debt Security of CEE Countries: Actual Approaches and Methods of Evaluation

The study is aimed at analyzing methods of country’s debt security evaluation, developing methodic approach towards estimating the level of debt security based on the calculation of the integral index, and assessing the level of debt security of CEE countries on the basis of the proposed approach. A method of calculating the integral debt security index of the country is developed, taking into account generally accepted thresholds of indebtedness and solvency indicators and the trend of countries’ increasing dependence on external borrowing. The proposed approach is practically tested in assessing the level of debt security of CEE countries. It is determined that the group of CEE countries is differentiated by the state of indebtedness and solvency. The highest level of debt security is demonstrated by Bulgaria, the Czech Republic and Estonia, the worst situation with the debt security is formed in Slovakia and Slovenia. Based on the analysis of the dynamics of integral debt security indices for 2007–2019, the grouping of CEE countries by the level and zones of debt security, the trends of deterioration of the region’s debt security in 2010–2015 and its improvement in 2016–2019 has been found out. The proposed approach is universal one; it can be used to calculate debt security indices and to provide comparative studies of the debt sector of any country or region. It can also help to identify weaknesses in country’s debt security that is critically important for reasoning the public policy measures to ensure a proper level of debt security.

Validation of an Image Analysis Method for Evaluating the Chemical Resistance of Glass Fibers to Alkaline Environments

This article is focused on the comparison of the reliability of the results obtained by image analysis (newly proposed evaluation method) with well-known methods of evaluation of long-term corrosion resistance of glass fibers in an alkaline environment (pH > 12). The developed method is based on the analysis of scanning electron microscopy images (diameter and structures on the fiber surface). An experiment (52 weeks) was performed to evaluate two types of glass fibers: anticorrosive glass fibers (ARGFs) and E-glass fibers (EGFs). Three media were used to treat the fibers (23 ± 2 °C): H2O, Ca(OH)2, and K2SiO3. The ARGFs’ tensile strength did not reduce; a decrease by 68% was observed for EGFs in H2O. Tensile strength decreased by 32% and 85–95% in K2SiO3; by 50% and 64% in Ca(OH)2 for the ARGF and EGF, respectively. Statistical analysis was performed to validate the reliability and plausibility of the developed method. ARGFs and EGFs did not show any relationship between the fiber diameter and weight in H2O; however, the linear trends may predict this relationship in Ca(OH)2 and K2SiO3. For the ARGF and EGF, the cubic trend was suitable for predicting the change in fiber weight and diameter over time in Ca(OH)2 and K2SiO3.

Development of an Experimental Setup to Investigate Influences on Component Distortion in Gravity Die Casting and a First Variation of Temperature Control Strategy

Distortion (1), residual stresses and hot cracks can facilitate significant decreases in quality characteristics of casting products. Their reduction by a suitable component design (2) and process control is therefore desirable. In the casting process, these characteristics are assumed as a result of the combination of solidification shrinkage paired with the local self-feeding and the geometric constraints imposed on the component by the mold. In gravity die casting (3) of aluminum (4) with thermally well conducting and rigid metal molds, the control of solidification through a localized adjustment of the heat balance (5) appears to be a suitable approach to minimize these effects. The development of an experimental setup for the assessment of the interdependencies of the alloy, casting geometry and cooling are described in this work. A first series of experiments with A356 aluminum alloy and the introduction to the different methods of evaluation are presented. Furthermore, an approach to improve the understanding of the underlying mechanisms is outlined.

Methods of evaluation of production and technological work with shipbuilding

Оценка и анализ производственно-технологических работ судостроительных предприятий обусловлен необходимостью обеспечения конкурентоспособности вновь создаваемых объектов морской техники с показателями качества на уровне лучших мировых образцов с одновременным повышением темпов технико-экономического развития их производства. Названная проблема диктует необходимость адекватной оценки состояния технического оснащения производства, а также наиболее эффективных направлений вложения средств на техническое перевооружение. Техническое оснащение производства во многом зависит от уровня автоматизации, механизации технологических процессов, объёмов ручных работ, конструктивно-технологических особенностей создаваемых объектов морской техники, серийности производства и т.д. Для судостроения, судового машиностроения с учётом единичного и мелкосерийного производства характерна высокая доля ручного труда, особенно при выполнении механомонтажных работ. В статье предложен принципиально новый подход к оценке производственно-технологических работ (уровней технического оснащения производства) судостроительных предприятий. Приведены результаты расчётов и оценки на примере переделов (видов работ) механомонтажного производства для группы отечественных судостроительных предприятий. Предложенный метод оценки производственно-технологических работ (потенциалов) универсален для любых видов судостроительных и машиностроительных работ. Evaluation and analysis of production and technological works of shipbuilding enterprises is conditioned by the need to ensure the competitiveness of newly created marine equipment facilities with quality indicators at the level of the world's best samples, while increasing the pace of technical and economic development of their production. This problem dictates the need for an adequate assessment of the state of technical equipment of production, as well as the most effective ways of investing funds for technical re-equipment. The technical equipment of production largely depends on the level of automation, mechanization of technological processes, the volume of manual work, the design and technological features of the created objects of marine equipment, serial production, etc. For shipbuilding, marine engineering, taking into account single and small-scale production, a high proportion of manual labor is characteristic, especially when performing mechanical installation work. The article proposes a fundamentally new approach to the assessment of production and technological works (levels of technical equipment of production) of shipbuilding enterprises. The results of calculations and estimates on the example of repartitions (types of work) are given mechanical assembly production for a group of domestic shipbuilding enterprises. The proposed method of evaluation of production and technological works (potentials) is universal for all types of shipbuilding and machine-building works.

MODERNIZATION EXPERIENCES IN PUBLIC EDUCATION SCHOOLS LIMITS OF THEIR EMPLOYMENT IN JERUSLAEM/ PALESTINE

The study aimed to identify learning from successes in public education schools in the East Jerusalem, and to uncover the effect of learning factors from successes in achieving learning from successes and determining their competitive advantage. The researchers followed the descriptive and analytical approach for its relevance to this study, and the researchers used the study tool (in-depth personal interview) With a sample of public education school principals in the West Bank in Palestine. The study focused on three main axes: 1. The first axis: learning from past successes retrospectively. 2. The second axis: the journey after the learning question: the future method. 3. The third axis: learning about learning: identifying and transmitting learning patterns at the individual and group levels. Each of these axes included a set of related questions that deal with the subject of the study. The results of the study showed the importance of learning from the successes in public education schools, following the success factors in achieving the desired goals, employing strategic planning, raising the motivation of human resources and the level of their personal and professional competencies, and following the methods of evaluation, evaluation and follow-up in school achievements. The researchers recommended the necessity of analyzing the school environment and identifying strengths and weaknesses in order to identify and follow success factors, and to invest and transfer creative and innovative ideas in employing success factors and achieving respiratory advantage.