Dilemmas in zirconia bonding: A review

This article presents a literature review on the resin bond to zirconia ceramic. Modern esthetic dentistry has highly recognized zirconia, among other ceramic materials. Biocompatibility of zirconia, chemical and dimensional stability, excellent mechanical properties, all together could guarantee optimal therapeutical results in complex prosthodontic reconstruction. On the other hand, low thermal degradation, aging of zirconia as well as problematic bonding of zirconia framework to dental luting cements and tooth structures, opened the room for discussion concerning their clinical durability. The well known methods of mechanical and chemical bonding used on glass-ceramics are not applicable for use with zirconia. Therefore, under critical clinical situations, selection of the bonding mechanism should be focused on two important points: high initial bond strength value and long term bond strength between zirconia-resin interface. Also, this paper emphases the use of phosphate monomer luting cements on freshly air-abraded zirconia as the simplest and most effective way for zirconia cementation procedure today

Aridity in the central and southern Pannonian basin

For the investigation of geographical, monthly, seasonal, and annual distributions of aridity and its annual trend in the region of the Central and Southern Pannonian Basin (CSPB), which includes the territories of Hungary and Vojvodina (Northern Serbia), the De Martonne Aridity Index (DMAI) was used. The DMAI was originally calculated from a total of 78 meteorological stations with the maximum available time series of climatological data in three cases: 1931–2017 for Hungary; 1949–2017 for Vojvodina; and 1949–2017 for Hungary and Vojvodina jointly. The Palmer Drought Severity Index (PDSI) was used to control the DMAI results. Temperature and precipitation trends were also investigated to understand their effects on the aridity trend. Three aridity types are distinguished on the annual level, five on the seasonal level, and four on the monthly level. The annual aridity had no trends in all three periods. It seems that aridity can be considered a more stable climate indicator of climate change than the temperature, at least in the CSPB. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Assessment of air temperature trend in South and Southeast Bosnia and Herzegovina from 1961 to 2017

Recent climate change has been caused by interaction of natural processes and the anthropogenic factor. In turn, it incites the pronounced natural and socio-economic changes. It is the air temperature that plays a pertinent role in understanding the climate change problem. Southeast Europe, including Bosnia and Herzegovina (B&H), is highly relevant for the observations of regional differences in changes of air temperature regime. From the regional-geographical point of view, South and Southeast B&H cover 26.5% (13.568 km²) of B&H territory (51.209 km²). It is from south and southeast that the Mediterranean impacts from the Adriatic Sea penetrate into the defined region, which further affects the variability of climate conditions in B&H. The paper presents trends in three parameter categories: mean annual, mean maximum, and mean minimum air temperatures in the territory of South and Southeast B&H. The aim of the paper is to demonstrate the likely climate change based on air temperature trends. Methodologically, temperature trends were processed by using the Mann-Kendall trend test. For the purpose of the analysis, available data from four meteorological stations in South and Southeast B&H for a 56-year period were used. Based on the obtained results, a statistically relevant positive trend was observed in all twelve time series. According to the analyzed trends, the increase of air temperature was dominant in the target area. The application of Geographical Information System (GIS) tools indicated the presence of regional differences in air temperature distribution. An evident phenomenon is the combined impact of the orography of the region and the maritime influence. The occurring climate change affects specific social sectors, so the problem must be addressed properly. Another pertinent fact is that the climate change problem has not been adequately analyzed in the strategic documents in B&H

Extreme floods in Serbia occurring simultaneously with the high water levels and heavy rains : case study

This paper discusses possible development or so-called scenario of extreme floods in the Republic of Serbia that would be caused by simultaneous occurrence of high-water levels/discharges on the rivers and heavy rains. As illustration, two scenarios are presented based on independently recorded cases of high water levels and heavy rains of May 2014. A scenario of the floods caused by the interaction of reached high water levels and observed heavy rains is particularly examined. Research of the floods is proposed with the parameters of flood waters that would not have highly unexpected values, but would be more extreme than all the past ones. Scenarios would yield new potentially useful information on the influence of floods on human communities. Proposals are presented for more efficient controlling and regulating of floods in the Republic of Serbia

Classification of natural disasters between the legislation and application: experience of the Republic of Serbia

The paper discusses the definitions of natural disasters and recommends the implementation of definitions and classifications of natural disasters in accordance with those decreed at the Centre for Research on the Epidemiology of Disasters (CRED) and Munich Re insurance Company (Munich RE) for administrative use in the Republic of Serbia. For the Republic of Serbia, the issue of natural disasters is presented both through government documents (e.g. the Law on Emergencies and the National Strategy of the Protection and Rescue in Emergencies) and the survey of the frequency and typology of disasters. Significant discrepancies exist between older and more contemporary classifications of disasters in Serbia. They are especially emphasized in comparison to the CRED and Munich RE classifications and databases. This causes problems in the monitoring, recording and assessment of the effects of natural disasters. It is proposed that definitions be adapted and implemented into legislative and other documents

Forest fire analysis and classification based on a Serbian case study

A recent forest fire in the Republic of Serbia is discussed concerning classification, legislative framework and fire management, giving a detailed analysis of the forest fire occurrence. Analysing past and predicting future fires are crucial for policy development and forest management practices to prevent and mitigate fires. Fire hazard is discussed through several fire protection and prevention legislative documents. The nonparametric Mann-Kendall test was used to analyse resent forest fire data in an attempt to find causality in occurrences and frequency. The meteorological data and fire statistics provided by the Serbian Hydro-meteorological Service and the Ministry of Interior/Sector for Emergency Management of the Republic of Serbia were used to calculate the Forest Fire Weather Indices, along with deficit or surplus of precipitation for the case study of Tara Mountain. The paper highlights the need for better hierarchical classification of fire hazards and its harmonisation along with standardisations presented by leading international research institutions. A significant correlation between meteorological parameters and forest fire occurrence was found. This opens a possibility for further investigation and analysis of geophysical and anthropogenic driven factors that can influence disaster occurrence

Photography in dentistry

Photography offers precious support in all areas of medicine and dentistry. Usage of photography in dentistry is an integral part of numerous diagnostic and therapeutic procedures and an important document of progression and outcome of subscribed therapy. Various types of cameras are available for intraoral and extraoral photography. Market offers different kinds of photographic equipment to dental practitioners such as cameras with films (Single Lens Reflex) SLR, digital SLR (DSLR) and compact digital cameras. However, majority of analyses emphasize advantages and relevancy of digital cameras, especially in taking macro photographs in dentistry. Introduction of digital cameras in dental practice is an important step toward the future. The aim of this study was to point out the importance of photography in dentistry, demonstrate basic technology of contemporary cameras and to analyze advantages and disadvantages of available cameras

Basic pulmonary function tests in pig farmers

INTRODUCTION Many epidemiological and clinical studies have demonstrated an increased risk for the symptoms of respiratory disorders consistent with chronic bronchitis and asthma and alterations of pulmonary function tests in pig farmers. AIM The aim of this study was to determine basic pulmonary function values in workers in swine confinement buildings and to compare them with the same values in the control group of unexposed persons. The next aim was to examine the association between these values with duration of professional exposure, cigarette smoking, age, and sex of the examined persons. METHODS We randomly selected for examination 145 workers of both sex who had worked for at least 2 previous years in pig farms and spent at least 3 hours per day, 6 days per week in a swine confinement building. The farmers worked at 6 different farms with 12,383 pigs on average on each farms. The subject was eligible for the study if he had had no history of atopic disease nor any serious chronic disease, and no acute respiratory infection within 3 previous months. As control group we examined 156 subjects who had lived and/or worked in the same areas and had had no history of exposure to farming environment or any other known occupational air pollutants. In both groups the study comprised cigarette smokers and persons who had never smoked. Pulmonary function data were collected according to the standard protocol with a Micro Spirometer, (Micro Medical Ltd, England, UK). The registered parameters were FEV1 and FVC At least three satisfactory forced maximal expirations were performed by each subject and the best value was accepted for analyses. The results were also expressed as a percentage of predicted values and FEV1/FVCxlOO was calculated. RESULTS There were no differences in the main demographic characteristics between two examined groups (Table1). Mean duration of work in pig farming was 11.6 years (SD=8.5; range 2-40). The average values of examined pulmonary function tests are shown in table 2. The values of FEV1 and FVC in each groups were between 92% and 97% of predicted values, and FEV1/FVCx100 was not lower than 82%. There were no differences in the average values of FEV1 (p=0.574) and FEV1 % predicted (p=0.653) between pig farmers and control subjects. Pearson coefficient of correlation and Spearman nonparametric correlation test revealed a high level of correlation of FEV1 values with sex and age and no correlation of pig farming exposure with cigarette smoking as predictor variables (Table 3). The analysis by linear regression method showed that all examined predictor variables had the effect on the value of FEV1 (Table 4). After the elimination of the two least significant predictor variables it was possible to make the equation for prediction of FEV1 values. DISCUSSION In the present study there are no significant alterations in the values of the basic pulmonary function tests in pig farmers. In the majority of previous similar studies the differences in the average values of FEV1 and FVC between pig farmers and control subjects were also not found. However, in some studies the alterations in several more specific lung function parameters were registered. The decreased values of FEV1 during workshift were also found and they are probably connected to the bronchial hyper reactivity registered in many studies in pig farmers. Longer exposure to swine confinement environment caused more decline in FEV1 and FVC and accelerated mean age-related annual decline in FEV1 was observed reaching to 44 ml/yrs more than expected. The correlations between values of FEV, with pig farming exposure and cigarette smoking in this study were not found. However, the analysis by linear regression method showed that all examined predictor variables had the effect on the value of FEV1. In a few previous bronchoscopic, BAL, and sputum studies some signs of inflammation and morphological changes of the respiratory tract were observed. The absence of important alterations in the basic spirometric measures in this and the majority of the previous studies suggests that early airway injuries may not be readily apparent using spirometric measures of lung function. CONCLUSION In contrast to other world studies, our study comprised an important number of women farmers, but alterations associated to sex were not found. To asses the lung function in these pig farmers after several years may be of great importance

The analysis of aridity in Central Serbia from 1949 to 2015

In this study, we apply De Martonne and Pinna combinative indices to analyze the aridity in Central Serbia. Our dataset consists of mean monthly surface air temperature (MMT) and mean monthly precipitation (MMP) for 26 meteorological stations during the period 1949-2015. MMT and MMP are used for calculating monthly, seasonal, and annual aridity indices for period of 66 years. According to the De Martonne climate classification, we determine five, three, and four types of climate on the monthly, seasonal, and annual basis, respectively. During the observed period, winter was extremely humid, spring and autumn were humid, and summer was semi-humid. Humid and semi-humid climate with Mediterranean vegetation are identified by the annual Pinna combinative index. We find that there is no change in aridity trend in Central Serbia for the period 1949-2015. Aridity indices are additionally compared with the North Atlantic Oscillation and El-Nino South Oscillation in order to establish a possible connection with the large-scale processes. Results are further compared with several earlier studies of aridity in Serbia. With this study, the analysis of aridity in whole Serbia has become complete