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The article addresses a critical and timely issue: improving safety in underground coal mining. The primary objective of the paper was to develop a research methodology based on modelling studies to identify and assess the state of methane hazards during mining operations. To achieve this, structural modelling of the physical and chemical phenomena occurring in mining regions was conducted using Computational Fluid Dynamics. The core research was performed using the finite volume method on a real longwall exploitation site ventilated by a Y-system. This approach enabled the determination of methane and oxygen concentration distributions in the mining region and goafs, treated as a porous and permeable medium. Based on these findings, potential fire and/or methane explosion hazard zones were identified in the goaf. The model test results underwent a validation process, comparing them with actual measurements. The determined errors were within an acceptable range, confirming the accuracy of the developed model of the mining region and the phenomena within it. Furthermore, the model was used to predict the locations of zones at risk of fire and/or methane explosion in the goafs, particularly in areas with potentially increased gas emissions. The results clearly demonstrate the significant potential of using model studies to diagnose and forecast methane hazards in underground mining operations. Identifying these potential danger zones allows for the implementation of preventive measures to reduce the likelihood of dangerous incidents.

The article addresses the issue of quality of life in cities based on developed methodology. A multidimensional approach was adopted, namely 28 subindices characterizing seven dimensions affecting the quality of life in 18 provincial cities in Poland. The developed methodology consisted of two stages. In the first stage, using the indicators, the values of quality-of-life indices for the studied dimensions were determined. In the second stage, using these results, the values of the total quality-of-life indices in the studied cities were measured. Then, rankings for the cities in question were created. In addition, based on the values of the dimension indices and total indices, the levels of quality of life were determined. Relationships between parameters characterizing the sizes of studied cities and their wealth and the determined quality of life were also measured. The Gray Rational Analysis method was used for ranking, and three objective analytical methods were used to determine index weights: Equal weight, Entropy and CRITIC, and the Laplace’s criterion. The results indicate that living standards in the studied cities vary widely, both in terms of the value of the total index and the indices of individual dimensions. The best living conditions were found in Warsaw (the capital of Poland), Białystok and Olsztyn, and the worst in Kielce and Szczecin.

The process of underground mining is one of the most complex and hazardous activities. In order to maintain the continuity and efficiency of this process, it is necessary to take measures to reduce this hazard. The paper addresses this issue by presenting a developed methodology for using model studies and numerical simulations to support the process of monitoring methane hazards. Its basis is the developed model of the region of underground mining exploitation along with the ventilation phenomena occurring in it. To develop it, the ANSYS Fluent program was used, based on the finite volume method classified as computational fluid mechanics. The model reflects both the geometries and physical and chemical phenomena occurring in the studied area, as well as the auxiliary ventilation equipment used during operation. The research was conducted for two variants of methane emissions from goaf zones, the first of which concerned the actual state of the mining area, and the second of which concerned increased methane emissions from these goaf zones. The purpose of the study was to determine the distribution of methane concentrations in the most dangerous part of the studied area, which is the intersection of the longwall and the tailgate, as well as the distribution of ventilation air flow velocities affecting them. The studies for both variants made it possible to determine places particularly exposed to the occurrence of dangerous concentrations of methane in this region. The methodology developed represent a new approach to studying the impact of methane emissions from goaf zones into mine workings.

Underground mining production is an extremely important process for the economy and carried out in very difficult and complex environmental conditions. The disturbance of the balance of this environment makes it also a very dangerous process. Due to the importance of coal, mainly as an energy raw material, the process of its exploitation is carried out all over the world. The specificity of its production is mainly determined by mining and geological conditions, which determine the method of operation and the selection of machines and devices for this process. One of the most dangerous natural hazards associated with this process are ventilation hazards, including methane hazard. The reason for this threat is methane, an odorless and colorless gas, which becomes a flammable and explosive gas under certain criteria. These features make this gas a huge threat to mining operations. Its huge amounts, contained in coal seams, are released into the mine atmosphere during the exploitation process, causing a very high threat to work safety. Events related to the occurrence of methane are most often the cause of mining disasters, in which people die and the technical and mining infrastructure is destroyed. The reason for the growing methane hazard is the increasingly difficult mining conditions, and mainly the increasing depth of mining, and thus also the increase in methane-bearing capacity of the seams. Taking into account the huge impact of methane hazard on the mining process, the article discusses its impact on the safety and efficiency of this process. The results of the literature review with regard to this risk are presented and the accident statistics are presented. On the basis of actual data, an analysis of interruptions in the exploitation process related to exceeding the permissible methane concentrations was carried out in one of the mines. The problem of limiting the production process due to these exceedances is an important factor reducing the efficiency of this process. The obtained results clearly indicate that the losses resulting from these breaks deteriorate the profitability of the entire process and affect the economic efficiency of the industry. In order to effectively counteract the dangerous phenomena related to the methane hazard and to improve the efficiency of the mining production process, solutions were proposed to improve this state and the directions for further research were proposed.

During ventilation of longwalls, part of the air stream migrates into goaves with caving. In the case where these goaves contain coal susceptible to spontaneous combustion, such air flow through the goaves may lead to the formation of favourable conditions for coal oxidation and, subsequently, for its self-heating and spontaneous combustion. The ensuing endogenous fire may constitute a serious hazard to the mining crew and underground operations. The article presents the results of a numerical analysis of air stream flowing through the goaves of a longwall with caving ventilated with the U-type system from the exploitation field borders. The purpose of the analysis was to demarcate the zone with a particularly high risk of endogenous fires within the goaves. The hazardous values of air flow speed and oxygen concentration in the goaves, responsible for the commencement of low-temperature coal oxidation, were determined for specific mining and geological conditions. [ABSTRACT FROM AUTHOR]

Dustiness of the mine atmosphere during carrying out exploitation is one of the most hazardous factors threaten to health and life of employees. Also it is large hazard for all type of mechanical and electrical devices operating in mining headings. Coal dust is also very dangerous due to its possibility of explosion. Currently applied technologies of rock mass mining process, entire transport process of output and applied ventilation system cause that rock and coal dust is presented practically in each of the mining heading. Practically, is impossible to eliminate dust from mining headings. However, one can determine its parameters and potential ways its displacement. In the paper there is presented modeling research methodology of dustiness state in a driven dog heading. Developed model is the basis for this methodology, including the diphase flow of mixture of air and dust in the mining heading. Analysis was performed for real driven dog heading. Based on performed analyses, distributions of particular fraction and movement trajectories of selected dust grains were determined. Developed methodology gives a lot of opportunities for analysis of dustiness state in mining headings and in other compartments. It enables to determine parameters of particular grains and their impact on ventilation parameters of the air stream in the tested headings. Obtained results can also be used to reduce dust hazard.

Underground extraction of coal is characterized by high variability of mining and geological conditions in which it is conducted. Despite ever more effective methods and tools, used to identify the factors influencing this process, mining machinery, used in mining underground, work in difficult and not always foreseeable conditions, which means that these machines should be very universal and reliable. Additionally, a big competition, occurring on the coal market, causes that it is necessary to take action in order to reduce the cost of its production, e.g. by increasing the efficiency of utilization machines. To meet this objective it should be pro-ceed with analysis presented in this paper. The analysis concerns to availability of utilization selected mining machinery, conducted using the model of OEE, which is a tool for quantitative estimate strategy TPM. In this article we considered the machines being part of the mechanized longwall complex and the basis of analysis was the data recording by the industrial automation system. Using this data set we evaluated the availability of studied machines and the structure of registered breaks in their work. The results should be an important source of information for maintenance staff and management of mining plants, needed to improve the economic efficiency of underground mining.

One of the most dangerous and most commonly present risks in hard coal mines is methane hazard. During exploitation by longwall system with caving, methane is emitted to mine heading from the mined coal and coal left in a pile. A large amount of methane also flows from neighboring seams through cracks and fissures formed in rock mass. In a case of accumulation of explosive methane concentration in goaf zone and with appropriate oxygen concentration and occurrence of initials (e.g. spark or endogenous fire), it may come to the explosion of this gas. In the paper there are presented results of numerical analysis of mixture of air and methane streams flow through the real heading system of a mine, characterized by high methane hazard. The aim of the studies was to analyze the ventilation system of considered heading system and determination of braking zones in goaf zone, in which dangerous and explosive concertation of methane can occur with sufficient oxygen concentration equal to at least 12%. Determination of position of these zones is necessary for the selection of appropriate parameters of the ventilation system to ensure safety of the crew. Analysis of the scale of methane hazard allows to select such a ventilation system of exploitation and neighboring headings that ensures chemical composition of mining atmosphere required by regulation, and required efficiency of methane drainage. The obtained results clearly show that numerical methods, combined with the results of tests in real conditions can be successfully used for the analysis of variants of processes related to ventilation of underground mining, and also in the analysis of emergency states.

The process of underground coal production is inseparably connected with methane emissions. This gas has good energy characteristics and, at the same time, represents a huge threat to the safety of mining exploitation. Due to its flammability and explosiveness, the occurrence of methane-related incidents disturbs the entire production process and is extremely dangerous for the crew. Moreover, methane is a greenhouse gas that has a highly negative impact on the natural environment. These factors make it necessary to carry out works in order to limit its negative effects and increase its use as an energy raw material. The article presents the results of an analysis of the main parameters describing the methane-bearing capacity in Polish hard coal mines. The analysis was conducted within the scope of their absolute values and with reference to one tonne of coal extracted. The purpose of these studies was to identify the changes in the parameters under analysis over the last 25 years in the Polish mining industry and, at the same time, to determine how the structural changes in the mining industry and the entire economy influenced those parameters. This particularly concerns the emission of methane into the environment. The reason is that this value has a huge influence on the opinion about the mining industry. The results presented should be used for works on limiting the harmful effects of methane and increasing the degree of its utilisation in the economy.

When ventilation hazards become active in an underground mine heading, it is very often necessary to evacuate the crew from the danger area. This evacuation is carried out along emergency escape (evacuation) routes to a heading which is not affected by a given incident. Such a heading must provide access to fresh air and guarantee that there is no smoke. In this context, an important role is played by the time in which the crew leaves the danger area and gets into the safety zone. The time needed by the crew to cover the length of an escape route depends on a number of factors. In hard coal mines, the time necessary to evacuate the crew is most commonly determined on the basis of analytical methods developed in the second half of the 20th century. In recent years, however, the development of numerical methods has made it possible to determine these times using model-based tests supported by numerical simulations. The article presents the results of such tests with regard to the evacuation of a crew from an excavated dog heading. The objective of the tests was to analyse how the movement speed of the miners being evacuated from the danger area affects the time of their evacuation. The analysis was carried out for four different movement speeds of a crew and for 26 miners working in the heading under analysis. Their distribution in the heading reflected the actual location of their work stations. The results obtained made it possible to determine the times and intensity of their evacuation, and they should also serve as a valuable source of information for the emergency rescue teams in underground mines.

Hazard of endogenous fires is one of the basic and common presented occupational safety hazards in coal mine in Poland and in the world. This hazard means possibility of coal self-ignition as the result of its self-heating process in mining heading or its surrounding. In underground coal-mining during ventilating of operating longwalls takes place migration of parts of airflow to goaf with caving. In a case when in these goaf a coal susceptible to self-ignition occurs, then the airflow through these goaf may influence on formation of favorable conditions for coal oxidation and subsequently to its self-heating and self-ignition. Endogenous fire formed in such conditions can pose a serious hazards for the crew and for continuity of operation of mining plant. From the practical point of view a very significant meaning has determination of the zone in the goaf with caving, in which necessary conditions for occurence of endogenous fire are fulfilled. In the real conditions determination of such a zone is practically impossible. The main aim of the analysis was to determine the impact of type of the roof rocks forming the goaf on the location and range of endogenous fires particular hazard zone by in these goaf. For determined mining-geological conditions, the critical value of velocity of airflow and oxygen concentration in goaf, conditioning initiation of coal oxidation process were determined.

Determination of effective use of mining devices has very significant meaning for mining enterprises. High costs of their purchase and tenancy cause that these enterprises tend to the best use of possessed technical potential. However, specifics of mining production causes that this process not always proceeds without interferences. Practical experiences show that determination of objective measure of utilization of machine in mining enterprise is not simple. In the paper a proposition for solution of this problem is presented. For this purpose an IT platform and overall efficiency model OEE were used. This model enables to evaluate the machine in a range of its availability performance and quality of product, and constitutes a quantitative tool of TPM strategy. Adapted to the specificity of mining branch the OEE model together with acquired data from industrial automatic system enabled to determine the partial indicators and overall efficiency of tested machines. Studies were performed for a set of machines directly use in coal exploitation process. They were: longwall-shearer and armoured face conveyor, and beam stage loader. Obtained results clearly indicate that degree of use of machines by mining enterprises are unsatisfactory. Use of IT platforms will significantly facilitate the process of registration, archiving and analytical processing of the acquired data. In the paper there is presented methodology of determination of partial indices and total OEE together with a practical example of its application for investigated machines set. Also IT platform was characterized for its construction, function and application.

Aim: To compare implant survival and complication rates between shorter and standard-length implants with sinus augmentation and restored with single crowns, at 10 years of loading., Materials and Methods: One-hundred and one patients (137 implants) with a ridge height of 5-7 mm in the posterior maxilla were randomly assigned to two treatment modalities: shorter implants (6 mm) (group short [GS]) or standard-length implants (11-15 mm) with sinus grafting (group graft [GG]). Following the insertion of final restorations, patients were regularly recalled for up to 10 years. Assessed outcomes encompassed implant survival, marginal bone levels (MBLs), biological and technical parameters and patient-reported outcome measures (OHIP-49 = Oral Health Impact Profile). Non-parametric statistical analysis was used to analyse the data., Results: For the 5- to 10-year follow-up period, 77 patients with 105 implants (GS: 36 patients/48 implants; GG: 41/57) were available for re-examination (drop-out rate 21%). Implant survival rates at the patient level were 96.0% (GS; 2 failures) and 100% (GG) (inter-group p = .24). Median MBLs amounted to 0.00 mm (min 0.00; max 3.25; GS) and 0.00 mm (min 0.00; max 4.55; GG) (inter-group p = .73). Technical complications predominantly occurred within the first 5 years (inter-group p > .05). Peri-implantitis rates were 4.2% (GS) and 13.3% (GG) (intergroup p = .37). Median OHIP-49 scores were 7.00 (0.00; 39.00; GS) and 9.00 (0.00; 196; GG) (inter-group p = .61) at 10 years., Conclusions: Based on similar 10-year implant survival rates, reduced patient morbidity and lower costs, the use of shorter dental implants might well serve as an alternative treatment concept to longer implants placed in conjunction with sinus grafting for patients with a limited ridge height in the posterior maxilla. Study register: https://clinicaltrials.gov/ct2/show/NCT01030523., (© 2024 The Authors. Journal of Clinical Periodontology published by John Wiley & Sons Ltd.)

Underground mining belongs to immensely complex processes and depends on many natural, technical and organizational factors. The main factor that hinders this process is the environmental conditions in which it is carried out. One of the problems associated with the use of increasingly modern machines in such conditions is the issue of unplanned downtime during their operation. This paper presents the developed methodology and IT system for recording breaks in the operation of mining machines and identifies their causes. The basis of this methodology is a sensor-based information system used to register mining machinery parameters, based on which interruptions in their operation can be determined. In order to register these parameters, an industrial automation system (together with a SCADA system supervising the process) was used, which is practically independent from the operator and enables continuous registration of these parameters. In order to identify the reasons for the recorded breaks, an IT tool was developed in the form of an application in the module of the integrated mining enterprise management support system (ERP system). This application enables (with a continuously updated database) the identification of the causes in question. Thus, the developed solution enables the objective registration of machine downtime and, for most cases, the identification of causes. The acquired knowledge, so far largely undisclosed, has created opportunities to improve the utilization level of machinery exploited in the mining production process. The paper discusses the methodology, together with the IT system, for identifying the causes of machine downtime and presents an example of its application for a shearer loader, which is the basic machine of a mechanized longwall system. The results indicate great potential for the application of the developed system to improve the efficiency of machinery utilization and the whole process of mining production.

The industrial sector is one of the most important sectors of the global economy, having a huge impact on the development of individual countries and regions. This sector covers a wide and diverse range of activities, which makes it of key importance for the economy of the European Union (EU) countries. As a result, the processes related to energy transformation and climate policy are increasingly connected with the sector in question. The need to improve the competitiveness of the economy and the implementation of climate and energy strategies means that this sector, like the entire EU economy, must rapidly enhance its energy efficiency and the structure of energy consumption. The following paper addresses this problem by presenting the results of a comprehensive study of the structure and volume of energy consumed by this sector in the period between 1995 and 2019. Based on this study, quantitative changes and the structure of energy consumed in this sector in the studied period were determined for the entire EU and its individual countries. The use of the Gini coefficient and the Lorenz curves allowed for the determination of the inequality of energy consumption in the industrial sector. The coefficients of variation and the dynamics of changes in energy consumption, both in total and from individual sources, for the EU countries were also determined. The aim of this part of the study was to indicate directions and the intensity of changes related to the structure and consumption of energy in this sector. In the next stage, groups of similar countries were created and compared in terms of the structure of energy consumed by the industrial sector in 1995 and 2019 (using the Kohonen's neural network). Relationships between the amount of energy consumed by the industrial sector in the entire EU and the basic economic and climate parameters of the economy were also delineated. The energy intensity of this sector and the dynamics of its changes in individual EU countries over the analyzed period were also specified. The results proved a great diversity of the EU countries and the improving energy efficiency and structure of energy consumed by the industrial sector. The research, together with its results, significantly broaden the knowledge of changes in the volume and structure of energy consumption in the industrial sector for the EU countries. The results make it possible to assess the actions of individual countries and the current state of implementation of EU climate and energy policy. They should also be used to develop future assumptions of this policy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The growing social awareness of environmental protection entails that the assumptions of the sustainable development idea are being implemented in various economic sectors at an increasingly fast pace. One of them is the power industry, the sustainable development of which is now becoming a priority in economic policy for many countries. The paper refers to this issue by developing methodology for both studying and assessing the level of sustainable energy development in the Central and Eastern European Countries. The study involved 21 indicators characterizing the sustainable energy development of these countries in the areas of energy, environmental, economic, and social security for 2008 and 2018. When considering the complexity of the subject matter and the wide scope of the research, four methods of multi-criteria data analysis (TOPSIS, VIKOR, MOORA and COPRAS) were used. For each of them, based on the adopted criteria, synthetic indicators were determined, which allowed for the assessment of the level of sustainable energy development in the CEE countries. Weights for the adopted indicators were identified based on the Shanon's Entropy method. Afterwards, an unambiguous assessment of the level of sustainable energy development of the CEE countries was performed. The results showed that in 2008 and 2018, the best ranking position was held by Latvia and Croatia, and the worst ranking position was held by Poland and Bulgaria. The method of multidimensional scaling made it possible to determine the positions of studied countries on scatter plots in two-dimensional space, which showed differences between individual CEE countries. All in all, the applied methods allowed for a considerably broad assessment of the level of sustainable energy development of the CEE countries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

One of the main reasons for the dynamic global economic development observed in recent years is the process of digitalization, referred to as Industry 4.0. The significance of digitalization for this development is appreciated by the EU-27. In order for these actions to be effective, it is necessary to diagnose the current level of digitalization in the EU-27countries. The article presents the results of the assessment of the level of digitalization of enterprises in the EU-27 countries. An empirical analysis was conducted using 16 determinants which describe the digitalization in a sample of 27 EU countries. Based on the adopted criteria and the Technique for Order Preference by Similarity to an Ideal Solution method, these countries were divided into four classes in terms of the level of digitalization. The analysis looked at the size of enterprises and was performed independently for small, medium and large enterprises. The adopted indicators allowed for the analysis of similarity between the EU-27 countries in terms of digitalization, using the Kohonen's networks. The result of this research was the division of the EU-27 countries into groups, also taking into account the size of studied enterprises. Due to the immensely diverse EU-27 economy, such a huge undertaking as the digital transformation process requires building logical internal "digital coalitions". The designated assessment and similarity between countries creates such opportunities, also in terms of building an effective policy to support these processes by the EU. This increases the chances of success of joint ventures and building a sustainable European community based on the latest technologies., Competing Interests: The authors have declared that no competing interests exist.

The process of global economic digitalization is a natural stage of evolutionary changes resulting from a dynamic development of information and communication technologies. Having appreciated the importance and advantages of digital transformation, individual countries began to strive to introduce it as soon as possible. In this context, it is important to study the level of digital maturity in Central and Eastern Europe, where the level of digitization is relatively low. This article assesses the level of digital readiness of enterprises in these countries based on 14 determinants characterizing the most important areas of the digitalization process. The research was carried out for 11 countries from the region, both for all and manufacturing enterprises. Multi-criteria analysis aimed at assessing the digital maturity of countries were performed using the Multi-Criteria Decision-Making methods (the TOPSIS, MOORA, VIKOR), and entropy methods for delineating the weights of the determinants. In order to obtain an unambiguous assessment of the determined digital maturity, the mean-rank method was applied. The method of multidimensional scaling allowed for the analysis of similarities between the countries in question. The results showed that the level of digital maturity in the Central and Eastern Europe countries varies greatly and is lower than in other European Union countries., Competing Interests: The authors have declared that no competing interests exist.

Based on the newly adopted strategy "The European Green Deal", by 2050, the European Union should become the first climate neutral region worldwide. This very ambitious goal will require many political, social and economic activities. Huge financial resources will also be needed to change the economy in order to reduce the emissions of harmful substances into the environment. The implementation of such an ambitious climate policy requires the development of a very reasonable economic plan, backed by many analyses, to ensure adequate financing of this idea. One of the basic objectives of such a plan should be to appropriately target aid funds to a group of countries with a similar structure of the emissions in question. The identification of the groups of similar countries in terms of the structure of harmful substance emissions requires the development of both appropriate methodology and applicable studies. Such methodology is presented in this paper, namely the Kohonen's artificial neural network model. The main objective of the developed methodology was to divide the European Union countries into groups similar in terms of the emissions of selected gases and dusts into the atmosphere. In addition to the division of the European Union countries into similar groups by the total volume of the emissions of studied substances, completely new division criteria were introduced. It was assumed that in order for the results of this study to be practically used, it is necessary to broaden the scope of the analysis. Therefore, an additional division of the European Union countries was made in relation to the volume of the emissions per capita, the value of gross domestic product and the area of a given country. This new approach was intended to show the diversity of the European Union countries in economic, demographic and geographical terms. The grouping results should be regarded as additional information to be utilized when preparing specific action plans to improve the state of the environment. Definitely, these plans need to be dedicated both to the groups of countries and the entire sectors in these groups. This will enable the efficient use of financial resources and can be a huge impetus for the European Union economic development. It will also allow smaller and less prosperous countries to achieve their goals. Undoubtedly, the developed methodology and conducted research allowed the authors to solve a significant research problem, and the results can be successfully used in practice., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2020 Elsevier Ltd. All rights reserved.)

Methane, which is released during mining exploitation, represents a serious threat to this process. This is because the gas may ignite or cause an explosion. Both of these phenomena are extremely dangerous. High levels of methane concentration in mine headings disrupt mining operations and cause the risk of fire or explosion. Therefore, it is necessary to monitor and predict its concentration in the areas of ongoing mining exploitation. The paper presents the results of tests performed to improve work safety. The article presents the methodology of using artificial neural networks for predicting methane concentration values in one mining area. The objective of the paper is to develop an effective method for forecasting methane concentration in the mining industry. The application of neural networks for this purpose represents one of the first attempts in this respect. The method developed makes use of direct methane concentration values measured by a system of sensors located in the exploitation area. The forecasting model was built on the basis of a Multilayer Perceptron (MLP) network. The corresponding calculations were performed using a three-layered network with non-linear activation functions. The results obtained in the form of methane concentration prediction demonstrated minor errors in relation to the recorded values of this concentration. This offers an opportunity for a broader application of intelligent systems for effective prediction of mining hazards., Competing Interests: The authors declare no conflicts of interest.

The article presents the analysis results of the grouping of the European Union countries with regard to emission levels of gaseous pollutants (NH3, NMVOCs, SO x , NO x ) and particulate air pollutants (PM10 and PM2.5) which are one of the most dangerous type of pollution for human health. Their long-lasting effects on the human body may negatively affect health and life expectancy. The analysis was based on the taxonomic method of grouping data using the K-means method which is a non-hierarchical method. The analysis used the data published by Eurostat. Organizing countries into categories of emissions of gaseous and dust pollutants to the atmosphere was conducted for four cases: the total level of emission, the level of emissions related to the GDP, the area, and per capita. The Euclidean distance was a measure of the distance between Member States. The obtained results indicate that, depending on the adopted criterion, there is a significant change in the composition of individual clusters. This confirms the assumptions of the Authors who claimed that in order to develop a more comprehensive analysis and assessment of the state of atmospheric pollution in EU countries it is necessary to include additional criteria, other than only the total emission of a given pollution. The objective of the research was to indicate that the analysis of emissions of selected type of pollution, and at the same time most threatening to human health, does not fully reflect the actual state of the problem when presented only in terms of the emitted amount. It is therefore appropriate for EU institutions to take more account of the differences between the individual countries in terms of the criteria presented in the paper, during the decision-making process concerning the sustainable development policy in the field of environmental protection., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The mining production process is exposed to a series of different hazards. One of them is the accumulation of dust which can pose a serious threat to the life and health of mine workers. The analysis of dust hazard in hard coal mining should include two aspects. One is the risk of coal dust explosions, which poses a direct risk of injury or even loss of life, the second is the risk of harmful dust, associated with the possibility of negative health effects as a result of long-term exposure to dust in the worker's body. The technologies currently applied in underground mining produce large amounts of coal and stone dust. Long-term exposure to dust and crystalline silica may cause chronic respiratory disease. The article presents the results of tests on the dust levels in the area of a fully-powered longwall. The tests were conducted for five longwalls from different hard coal mines. In each of them, the average values of inhalable and respirable dust as well as the percentage content of free silica in the dust were determined in ten selected working positions. Additionally, for the longwall with the highest dust concentration, the levels of dust were determined for the basic activities related to the phases of the technological cycle. The comparative analysis conducted and the results obtained demonstrate large variations in the dust levels in the different areas. The permissible values were significantly exceeded in a number of cases. This poses a great threat to the health of Polish miners. The results obtained indicate that it is necessary to undertake more effective measures in order to improve the working environment of the crew in hard coal mines.

Objectives: Technological development and the need for electronic health records management resulted in the need for a computer with dedicated, commercial software in daily dental practice. The alternative for commercial software may be open-source solutions. Therefore, this study reviewed the current literature on the availability and use of open-source software (OSS) in dentistry., Methods: A comprehensive database search was performed on February 1, 2017. Only articles published in peer-reviewed journals with a focus on the use or description of OSS were retrieved. The level of evidence, according to Oxford EBM Centre Levels of Evidence Scale was classified for all studies. Experimental studies underwent additional quality reporting assessment., Results: The screening and evaluation process resulted in twenty-one studies from 1,940 articles found, with 10 of them being experimental studies. None of the articles provided level 1 evidence, and only one study was considered high quality following quality assessment. Twenty-six different OSS programs were described in the included studies of which ten were used for image visualization, five were used for healthcare records management, four were used for educations processes, one was used for remote consultation and simulation, and six were used for general purposes., Conclusions: Our analysis revealed that the dental literature on OSS consists of scarce, incomplete, and methodologically low quality information.

Objectives: The aim of this study was to create an evidence-based three-dimensional cephalometric analysis of orbits in order to perform time-efficient measurements of postoperative orbital morphology changes., Materials and Methods: The authors used 23 (11 bilateral and 1 unilateral) anatomical landmarks. Based on these, 6 planes, 12 angular and 16 linear measurements were determined. A three dimensional analysis was performed twice by two observers on pre and post-operative computed tomography scans of six patients who had undergone midface advancement. The mean, minimal and maximal difference, as well as standard deviation (SD) and intraclass correlation coefficient (ICC) for the inter- and intra-observer landmark selection reliability were calculated. Additionally, the mean, minimal, maximal difference and standard deviation between pre- and post-operative angular and linear measurements were calculated to examine a connection between the established measurements and any morphological change., Results: The inter and intra-examiner accuracy of all landmarks for three axes was >0.9 ICC. Despite excellent inter and intra-examiner agreement (<2.49 mm ± 2.05 mm SD) for the landmark selection, linear and angular measurements showed a mismatch, the mean SD for angular measurements was found to be 8.2° and the linear 3.04 mm., Discussion: The possible causes of linear and angular measurement discrepancies are discussed and the future direction for the development of three-dimensional cephalometric analysis of orbits proposed., Competing Interests: None. Ethical Approval This article does not contain any studies with animals performed by any of the authors. All procedures performed in study involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Local ethics committee number 27/2013/V. Informed consent Informed consent was obtained from all individual participants included in the study.

Objective: The aim of this retrospective study was to investigate the most frequent complications and assess their overall rate associated with the surgical extraction of impacted teeth in an elderly patient population., Background: Oral health needs of the elders are often associated with surgical procedures for the creation of appropriate conditions for any further prosthetic treatment. One such process is the removal of severely decayed, fractured or impacted teeth detrimental to the fit or appearance of dentures. While broken and decayed teeth leave little doubt for their removal, impacted teeth divide opinion, some extreme regarding their prophylactic removal and the appropriate age for the procedure., Material and Methods: Material was selected from the archives of an Out-Patient Dental Surgery Clinic of the Regional Centre of Dentistry in Szczecin, from 2002 to 2013. The database was independently screened by two investigators according to inclusion and exclusion criteria. After selection process, all included records were screened using a data extraction form to obtain the necessary data., Results: The total number of impacted teeth was 73, of which 29% were partially impacted. The overall complication rate was 24.6%. The most common complications were as follows: haematoma, nerve disturbances and local infections., Conclusion: Surgical extraction in patients above 60 years of age is fraught with a high risk of possible complications., (© 2015 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.)

Aim: To compare, clinically and radiographically, short dental implants (6 mm) to long implants (11-15 mm) placed with sinus grafting., Methods: Participants with 5-7 mm of bone height in the posterior maxilla were randomly allocated to receive short implants (GS) or long implants with sinus grafting (GG). Implants were loaded with single crowns 6 months after placement (PR). Patients were re-evaluated 12 months after loading (FU-1). Outcome variables included: Implant survival rate (CSR), marginal bone level alteration (MBL), periodontal probing depth (PPD), bleeding on probing (BoP), plaque control record (PCR) and crown-to-implant ratios (C/I). Statistical analysis was performed using parametric tests., Results: In 97 subjects, 132 implants were re-evaluated at FU-1. The CSR was 100%. The MBL from implant placement (IP) to (PR) was -0.22 ± 0.4 mm for GG and -0.3 ± 0.45 mm for GS (p < 0.001). MBL from IP to FU-1 was -0.37 ± 0.59 mm for GG and -0.22 ± 0.3 mm for GS (p < 0.001). Intergroup comparisons showed non-significant differences for MBL (p > 0.05), PPD (p = 1) and PCR (p = 0.09). BoP was higher in the GS (p = 0.04). The C/I was 0.99 ± 0.17 for GG and 1.86 ± 0.23 for GS (p < 0.001). No correlation was observed between C/I and MBL, (GG: p = 0.13; GS: p = 0.38)., Conclusions: Both treatment modalities provided similar outcomes., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aim: To test whether or not the use of short dental implants (6 mm) results in an implant survival rate similar to long implants (11-15 mm) in combination with sinus grafting., Methods: This multicentre study enrolled 101 patients with a posterior maxillary bone height of 5-7 mm. Patients randomly received short implants (6 mm) (group short) or long implants (11-15 mm) with sinus grafting (group graft). Six months later, implants were loaded with single crowns and patients re-examined at 1 year of loading. Outcomes included treatment time, price calculations, safety, patient-reported outcome measures (OHIP-49 = Oral Health Impact Profile) and implant survival. Statistical analysis was performed using a non-parametric approach., Results: In 101 patients, 137 implants were placed. Mean surgical time was 52.6 min. (group short) and 74.6 min. (group graft). Mean costs amounted to 941EUR (group short) and 1946EUR (group graft). Mean severity scores between suture removal and baseline revealed a statistically significant decrease for most OHIP dimensions in group graft only. At 1 year, 97 patients with 132 implants were re-examined. The implant survival rate was 100%., Conclusions: Both treatment modalities can be considered suitable for implant therapy in the atrophied posterior maxilla. Short implants may be more favourable regarding short-term patient morbidity, treatment time and price., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The purpose of this study was to evaluate the use of short dental implants in distally reduced alveolar bone height., Material/methods: MedLine (PubMed and Ovid), ISI Web of Knowledge, and Cochrane databases were used for analysis. Searching was conducted using the search equation: 'Dental Implants' [Majr] AND (Short[TIAB] OR Shorter[TIAB]) AND (Implant[TIAB] OR Implants[TIAB]). Abstracts were screened by 2 independent reviewers. The articles included in the analysis were published in the English language and reported data on the use of implants with lengths below 10 mm in the posterior region with reduced alveolar bone height making the placement of longer implants impossible without additional surgical interventions. Articles concerning data on orthodontic implants and post-resection surgery reconstruction were excluded from analysis. Any disagreements between the 2 reviewers were resolved by a third reviewer. No time frame was used., Results: Of the 791 articles initially found, automatic rejection of duplicates in the Endnotes X5 software resulted in 538 articles. After the selection of studies from databases, a bibliography of 32 eligible articles was searched for other publications. Through this method, 2 more studies were added., Conclusions: The analysis of the results of different studies on the use of short dental implants showed that this treatment could be effective and comparable to the use of standard-length implants. This study revealed that rough-surfaced implants with lengths between 6-10 mm placed in the posterior mandible are the preferred solution. However, more detailed data will require additional prospective studies.

Introduction: Impacted maxillary canines are a serious problem in orthodontics and prosthodontics. The incidence of impaction has been reported at 3.3% of the general population and is more common among women. Impaction of canines can be unilateral or bilateral, palatal or labial. The causes of this pathology are varied. Irrespective of the cause of impaction, missing canines represent first and foremost an esthetic problem. The aim of this study was to analyze the possibilities of reconstructing missing permanent maxillary canines in a given clinical situation., Material and Methods: We present the case of a young female with bilateral impaction of permanent and retention of deciduous maxillary canines. A detailed orthodontic investigation ruled out the possibility of forced eruption of impacted canines. Consequently, surgical extraction of impacted canines and prosthetic replacement of missing teeth using endosseous implants were done., Results: The immediate functional and esthetic result in the patient was very good. As prosthetic crowns were cemented to the implants on the day of implantation, soft tissues received support without risk of contour change. The procedure ensured comfort for the patient without the need of wearing removable partial dentures., Conclusions: 1. Missing permanent canines represent a significant esthetic defect of dentition. 2. Surgical extraction and reconstructive treatment is an option when forced eruption of impacted canines proves impossible. 3. Close cooperation between the orthodontist and implant prosthodontist is necessary for a satisfactory esthetic result.

Introduction: The purpose of this work was to determine the influence of diabetic autonomic neuropathy on some basic properties of saliva such as volume of stimulated mixed saliva, concentration and secretion rates of sodium, potassium and calcium ions, and of glucose., Material and Methods: The study was carried out in 55 patients (25 females and 30 males). The study group consisted of 19 patients with type 2 diabetes mellitus and autonomic neuropathy affecting the cardiovascular system--DM-N(+). Two control groups were formed. One of them included 18 diabetic patients without any autonomic neuropathy--DM-N(-), the other (K) comprised 18 patients without diabetes. In the latter group there were nine patients on atropine (K-A) due to bradycardia and nine patients on propranolol (K-P) due to tachycardia. In the latter group, saliva samples were collected before and after administration of atropine or propranolol., Results: A significantly lower (p < 0.001) mean volume of stimulated mixed saliva was found in diabetic patients with autonomic neuropathy (1.91 +/- 0.34 mL) and control patients on atropine (K-A) (2.24 +/- 0.68 mL) as compared to DM-N(-) (5.37 +/- 0.78 mL) and K-P patients (5.51 +/- 1.05 mL). The volume of saliva did not correlate with glycosylated haemoglobin in either DM-N(-) or DM-N(+) groups. Secretion of glucose, as well as sodium, potassium and calcium ions to saliva was significantly lower in diabetics with autonomic neuropathy DM-N(+) and in non-diabetics after administration of atropine., Conclusion: Based on these results it was concluded that secretion of stimulated mixed saliva, glucose, as well as sodium, potassium and calcium ions is significantly reduced in autonomic neuropathy. These findings may be associated with lesions to parasympathetic nerve fibers caused by long-lasting diabetes.