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Number of results: 41
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Abstract

A method of creating production schedules regarding production lines with parallel machines is presented. The production line setup provides for intermediate buffers located between individual stages. The method mostly concerns situations when part of the production machines is unavailable for performance of operations and it becomes necessary to modify the original schedule, the consequence of which is the need to build a new schedule. The cost criterion was taken into account, as the schedule is created with the lowest possible costs regarding untimely completion of products (e.g. fines for delayed product completion). The proposed method is relaxing heuristics, thanks to which scheduling is performed in a relatively short time. This was confirmed by the presented results of computational experiments. These experiments were carried out for the rescheduling of machine parts production.

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Authors and Affiliations

Marek Magiera
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Abstract

In the paper, the results of investigations on the location of generating units most affecting the angular stability of a large power system (PS) are presented. For their location, the eigenvalues of the PS model state matrix associated with electromechanical phenomena (electromechanical eigenvalues) were used. The eigenvalues were calculated on the basis of the analysis of the disturbance waveforms of instantaneous power of the generating units operating in the PS. The used method of calculating eigenvalues consists in approximation of the disturbance waveforms of generating units by the waveforms being the superposition of modal components. The parameters of these components depend on the sought eigenvalues and their participation factors. The objective function was defined as the mean square error between the approximated and approximating waveforms. To minimize it, a hybrid algorithm, being a combination of genetic and gradient algorithms, was used. In the instantaneous power waveforms of generating units most affecting the PS angular stability, the least damped or undamped modal components dominate. They are related to eigenvalues with the largest values of real parts. The impact of individual modal components on the disturbance waveforms of subsequent generating units was determined with the use of participation factors and correlation coefficients of electromechanical eigenvalues.

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Authors and Affiliations

Piotr Pruski
ORCID: ORCID
Stefan Paszek
ORCID: ORCID
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Abstract

The main goal of introducing Active Suspension System in vehicles is to reduce the vehicle body motion under road obstacles which improves the ride comfort of the passenger. In this paper, the Full Car Model (FCM) with seven Degrees of Freedom is considered and simulated by MATLAB/Simulink. The Terminal Sliding Mode Controller (TSMC) and Fractional Order Terminal Sliding Mode Controller (FOTSMC) are designed to enhance the ride quality, stability and passenger comfort for FCM. The designed FOTSMC has the ability to provide higher control accuracy in a finite time. The performances of the designed controllers are evaluated by measuring the vehicle body vibration in both angular and vertical direction under bump input and ISO-8608 random input against passive suspension system. The FrequencyWeighted Root Mean Square (FWRMS) and Vibration dose value of Body Acceleration as per ISO-2631 are evaluated for FOTSMC, TSMC and PSS. The stability of the FCM is proved by Lyapunouv theory. Further analysis with sprung mass and speed variation of FCM demonstrate the robustness of proposed controller. To investigate the performances of designed controllers, comparison is made with existing Sliding Mode Controller (SMC) which proves that the designed FOTSMC performs better than existing SMC.

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Authors and Affiliations

T. Yuvapriya
P. Lakshmi
S. Rajendiran
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Abstract

Model predictive control (MPC) algorithms brought increase of the control system performance in many applications thanks to relatively easily solving issues that are hard to solve without these algorithms. The paper is focused on investigating how to further improve the control system performance using a trajectory of parameters weighting predicted control errors in the performance function of the optimization problem. Different shapes of trajectories are proposed and their influence on control systems is tested. Additionally, experiments checking the influence of disturbances and of modeling uncertainty on control system performance are conducted. The case studies were done in control systems of three control plants: a linear non- minimumphase plant, a nonlinear polymerization reactor and a nonlinear thin film evaporator. Three types of MPC algorithms were used during research: linear DMC, nonlinear DMC with successive linearization (NDMC–SL), nonlinear DMC with nonlinear prediction and linearization (NDMC–NPL). Results of conducted experiments are presented in greater detail for the control system of the polymerization reactor, whereas for the other two control systems only the most interesting results are presented, for the sake of brevity. The experiments in the control system of the linear plant were done as preliminary experiments with the modified optimization problem. In the case of control system of the thin film evaporator the researched mechanisms were used in the control system of a MIMO plant showing possibilities of improving the control system performance.

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Authors and Affiliations

Robert Nebeluk
Piotr Marusak
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Abstract

This paper proposes the development of a formation control algorithm of multiple acoustic underwater vehicles by employing the behaviour of autonomous mobile agents under a proposed pursuit. A robust pursuit is developed using the distributed consensus coordinated algorithm ensuring the transfer of information among the AUVs. The development of robust pursuit based on characteristics of multi-agent system is for solving the incomplete information capabilities in each agent such as asynchronous computation, decentralized data and no system global control. In unreliable and narrow banded underwater acoustic medium, the formation of AUVs based distributed coordinated consensus tracking can be accomplished under the constant or varying virtual leader’s velocity. Further, the study to achieve tracking based on virtual leader AUV’s velocity is extended to fixed and switching network topologies. Again for mild connectivity, an adjacency matrix is defined in such a way that an adaptive connectivity is ensured between the AUVs. The constant virtual leader vehicle velocity method based on consensus tracking is more robust to reduce inaccuracy because no accurate position and velocity measurements are required. Results were obtained using MATLAB and acquired outcomes are analysed for efficient formation control in presence of the underwater communication constraints.

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Authors and Affiliations

Bikramaditya Das
Bidyadhar Subudhi
Bibhuti Bhusan Pati
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Abstract

The paper is devoted to the finding of the coefficient of one nonlinear wave equation in the mixed problem. The considered problem is reduced to the optimal control problem with proper functional. Differentiability of functional is proved and the necessary optimality conditions are derived in the form of the variational inequality. Existence of the optimal control is proved.

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Authors and Affiliations

Zumrud R. Safarova
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Abstract

Building a Strategic Battery Value Chain in Europe COM/2019/176 is a priority for EU policy. Europe’s current share of global cell production is only 3%, while Asia has already reached 85%. To ensure a competitive position and independence in the battery market, Europe must act quickly and comprehensively in the field of innovation, research and construction of the infrastructure needed for large-scale battery production. The recycling of used batteries can have a significant role in ensuring EU access to raw materials. In the coming years, a very rapid development of the battery and rechargable battery market is forecast throughout the EU. In the above context, the recycling of used batteries plays an important role not only because of their harmful content and environmental impact, or adverse impact on human health and life, but also the ability to recover many valuable secondary raw materials and combine them in the battery life cycle (Horizon 2010 Work Programme 2018–2020 (European Commission Decision C(2019) 4575 of 2 July 2019)). In Poland, more than 80% of used batteries are disposable batteries, which, together with municipal waste, end up in a landfill and pose a significant threat to the environment. This paper examines scenarios and directions for development of the battery recycling market in Poland based on the analysis of sources of financing, innovations as well as economic and legal changes across the EU and Poland concerning recycling of different types of batteries and rechargable batteries.

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Authors and Affiliations

Agnieszka Nowaczek
ORCID: ORCID
Joanna Kulczycka
ORCID: ORCID
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Abstract

The subject of the research presented in this paper were financial results of mining industry enterprises (PKD 5 – P olish C lassification of A ctivity – “Mining of coal and lignite”) in 2007–2019. The research was conducted using relative and absolute financial measures, forming an extensive and coherent set of features characterizing their financial condition. The purpose was to measure and evaluate the efficiency of examined enterprises operation, considered as an attribute of development as well as factors describing and determining it. This evaluation was made against the background of ongoing restructuring processes taking into account their potential effects.

The article presents the course of the process of adapting P olish hard coal mining to market economy conditions after 1989. The process can be conventionally divided into several periods. The scope and intensity of changes in the mining industry followed the subsequent government programs for mining industry restructuring.

The lignite mining has not implemented any specific restructuring programs. The remedy processes were mainly related to organizational and ownership changes.

In relation to operation efficiency and value creation three turning points in the development path of enterprises were highlighted – 2011, 2015 and 2017, while the period of strong deterioration of results occurred in 2011–2015. I t was proved that restructuring processes did not affect the operating return on sales. However, there was a strong relation between changes in economic conditions on the coal market (prices) and the accumulation rate.

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Authors and Affiliations

Eugeniusz Jacek Sobczyk
Jarosław Kaczmarek
Kamil Fijorek
Michał Kopacz
ORCID: ORCID
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Abstract

Petřvald is a typical mining town in the Czech part of the Upper Silesian Basin. Since the Petřvald sub-basin is limited by significant tectonic structures, its development was to a great extent independent from other areas of the basin and can serve as an example of the influence of the geological structure on the development of mining and residential communities. In the first phase of mining development (ca 1830 to 1844) first claims begin to occur in the area. Thick coal seams were available in shallow depths. Due to missing railway connection, the demand for coal was not very large and the village economy was focused on agriculture. In the second phase (1844 to 1871), the first underground mines start to operate in the area. They were situated in favorable areas with thin overburden. Also, the connection to the railway improved the sale opportunities and a significant share of the local population worked in the mines. The third phase of mining (1871 to 1963) brought still increasing demand for coal, which resulted in establishing new coal mines in geologically less favorable areas (thicker overburden, water-bearing horizons). From the 1930s to the end of the 1950s the extraction peaked, which coincided with the urbanistic and cultural climax. New housing was provided for miners and their families by the companies. The final stage of mining development (1963 to 1998) is connected with the steady decline of production and phase-out of mining. The reason was a lack of economically recoverable coal reserves connected to unfavorable geological conditions. We conclude that the results of studies concerning specific geological parameters of coal deposits can be used for more detailed analyses regarding the development of urbanism, or to explain its causes.

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Authors and Affiliations

Martin Sivek
Jakub Jirásek
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Abstract

The paper presents areas where the EBITDA measure is used in coal companies. The metric and the ratios where it is utilized are employed to assess companies and management efficiency, hence they are used as criteria for rewarding board members. EBITDA-based ratios are also used to evaluate the profitability of company restructuring and its goodwill in mergers and acquisitions. EBITDA, also tends to be used to value companies on the capital market. It is a good tool for efficiency assessment in coal companies with relatively stable fixed assets and small share of intangible assets, which amortized over short periods of time could interfere the comparability of relations based on this measure. The comparability is also disturbed by large investment expenditure incurred in the short term. This does not apply to the mining industry, in which investment cycles are long, last several years and expenditures are spread over time. In addition, the rate of technical progress imposing the need to implement large technology projects is not high compared to technology companies with high development dynamics.

EBITDA based ratios were used to assess a number of listed coal companies. The analysis revealed that the profit/loss of these companies is mainly determined by coal prices. The cost of coal mining is 90% fixed and projects undertaken to reduce it bear fruit only over the long term. Cyclically changing coal prices cause major losses in companies when prices are low, which leads to bankruptcies or a need to restructure. After a period of decline in 2014–2016, the profit/loss of Polish coal companies as well as companies from around the world improved in 2017–2018. T he financial standing of Polish companies was better than that of their counterparts from other parts of the world.

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Authors and Affiliations

Agata Sierpińska-Sawicz
ORCID: ORCID
Maria Sierpińska
ORCID: ORCID
Elżbieta Królikowska
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Abstract

Emerging technologies represent the direction of the new industrial revolution of promoting sustainable economic and social development, and strategic emerging industries have developed rapidly in China. The development of these emerging technology industries requires more mineral resources as raw materials, especially the need for specific minerals, has increased. The unsatisfied growing demand for minerals used in emerging technologies or an unexpected supply disruption in major producing countries could have an impact on economic development. There are only several studies on the supply of mineral resources from the perspective of mineral resources needed by the development of China’s emerging industries. To assess the criticality of the minerals needed by the strategic emerging industries in China, this paper adopts three indicators: import concentration, the volatility of prices and the application requirements by the Chinese 13th five-year plan dedicated to strategic emerging industries in 2016. Furthermore, 34 types of nonfuel minerals and mineral raw materials are separated into three categories. Finally, this paper indicates that the three indexes are all high for 8 minerals with supply risks, application in emerging technologies, and substantial market fluctuations which need the support of special policies. Two indexes of three Level-II indicators are high for 14 minerals which need different policy combination measures, and one index is high for 12 minerals which also needs attention, all of which were analyzed.

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Authors and Affiliations

Yun Yu
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Abstract

Optimization in mine planning could improve the economic benefit for mining companies. The main optimization contents in an underground mine includes stope layout, access layout and production scheduling. It is common to optimize each part sequentially, where optimal results from one phase are treated as the input for the next phase. The production schedule is based on the mining design. Access layout plays an important role in determining the connection relationships between stopes. This paper proposes a shortest-path search algorithm to design a network that automatically connects each stope. Access layout optimization is treated as a network flow problem. Stopes are viewed as nodes, and the roads between the stopes are regarded as edges. Moreover, the decline location influences the ore transport paths and haul distances. Tree diagrams of the ore transportation path are analyzed when each stope location is treated as an alternative decline location. The optimal decline location is chosen by an enumeration method. Then, Integer Programming (IP) is used to optimize the production scheduling process and maximize the Net Present Value (NPV). The extension sequence of access excavation and stope extraction is taken into account in the optimization model to balance access development and stope mining. These optimization models are validated in an application involving a hypothetical gold deposit, and the results demonstrate that the new approach can provide a more realistic solution compared with those of traditional approaches.

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Authors and Affiliations

Jie Hou
Guoqing Li
Nailian Hu
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Abstract

The mines play an important role in the economic growth of countries since they are suppliers to many industries. In addition to the economic growth, the mines positively affect the social development factors such as the employment creation, the development of rural areas, building new roads, and etc. But sometimes it may lead to the negative environmental, and social impacts. Therefore, the mining activities should be carefully monitored for the concept of sustainable development. In this paper, a fuzzy Best-Worst Method based approach is developed for the evaluation of an iron mine. The case study, Sangan iron ore mine is one of the biggest mines, located in a rural area in the north eastern of Iran. Three factors including the economic, environmental, and social parameters were considered as main sustainable development criteria. The sub-criteria for each mentioned factor were then extracted from the literature as well as knowledge expert’s opinions. In the proposed approach, each sub-criterion was carefully weighted using the fuzzy Best-Worst method and scored by 12 experts. Afterwards, the sustainability score was defined as the summation of final fuzzy scores which was gone under a defuzzification process. The performance evaluation was calculated using this sustainability score resulted to a score of 0.626 out of 1, indicating its acceptable performance. The results showed that the mine performs well in terms of the economic benefits, rate of return, exploration capacity, and stockholders’ rights, but in the environmental management systems, water discharge, recreation and tourism aspects, it does not play well. The results of the implementation of the proposed approach showed the efficiency and effectiveness of the proposed approach that is confirmed by experts.

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Authors and Affiliations

Mehdi Pezeshkan
Hosseini Navid
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Abstract

The mining sector played an important role in the economic growth of the developed countries with rich natural resources in the past, and in recent years, it is important for the economic growth of developing countries. Also, it is generally supported by the incentives due to the fact that mining sector causes other related sectors to grow. Incentives have been the most important economic policy instrument imposed by governments to boost economic growth in developed and developing countries. Incentives or supports given by Turkish state in order to increase the mining investments can be analyzed under two categories; incentives or supports based on the Turkish Mining Law, incentives or supports provided under the Investment Incentive Program. The effect of investment incentives applied to the mining sector in Turkey between the years of 2001 and 2017 on mining production index (MPI) and also the indirect effect of these on gross domestic product (GDP) are investigated by using Granger Causality Test and regression analysis. In this study, the data belonging to the number of investment incentive certificates received by firms operating in Mining Sector and the amount of total fixed investment were used. According to the findings obtained from this study, it has been determined that encouraging the fixed investments of the firms operating in the Mining Sector with incentives has a significant and positive impact on MPI and GDP in a short period of 1 year. H owever, the incentives applied to the mining sector did not increase the production index of the mine in parallel with the increase in the GDP.

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Authors and Affiliations

Mehmet Aksoy
ORCID: ORCID
Adnan Konuk
Hakan Ak
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Abstract

Using the Konary anticlinal structure in central Poland as an example, a geological model has been built of the Lower Jurassic reservoir horizon, and CO2 injection was simulated using 50 various locations of the injection well. The carbon dioxide storage dynamic capacity of the structure has been determined for the well locations considered and maps of CO2 storage capacity were drawn, accounting and not accounting for cap rock capillary pressure. Though crucial for preserving the tightness of cap rocks, capillary pressure is not always taken into account in CO2 injection modeling. It is an important factor in shaping the dynamic capacity and safety of carbon dioxide underground storage. When its acceptable value is exceeded, water is expelled from capillary pores of the caprock, making it permeable for gas and thus may resulting in gas leakage. Additional simulations have been performed to determine the influence of a fault adjacent to the structure on the carbon dioxide storage capacity.

The simulation of CO2 injection into the Konary structure has shown that taking capillary pressure at the summit of the structure into account resulted in reducing the dynamic capacity by about 60%. The greatest dynamic capacity of CO2 storage was obtained locating the injection well far away from the structure’s summit. A fault adjacent to the structure did not markedly increase the CO2 storage capacity. A constructed map of CO2 dynamic storage capacity may be a useful tool for the optimal location of injection wells, thus contributing to the better economy of the enterprise.

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Authors and Affiliations

Katarzyna Luboń
ORCID: ORCID
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Abstract

The article presents the analysis of the correlation between the self-ignition parameters and the ultimate and proximate analysis, as well as the petrographic properties of Polish lignite, sub-bituminous coal, bituminous coal and anthracite. The following coal properties were determined: the moisture, ash content, volatile matter and sulfur content, gross calorific value, net calorific value, C, O, N and H contents, total porosity, ash oxide composition, rates of spontaneous combustion in 237°C and 190°C, and activation energy. During the petrographic analysis, maceral composition and random reflectance were determined. To determine the linear correlation between the self-ignition parameters and the analyzed coal properties, the Pearson correlation coefficient was calculated. The results show that there is no strong linear correlation between the lignite tendency to self-ignition and its petrographic properties. However, a strong negative correlation between the rate of spontaneous combustion and moisture and volatile matter content was observed. In the case of bituminous coal, strong correlations between self-combustion parameters and various coal properties were confirmed. The most noteworthy are the correlations between self-ignition parameters and the maceral composition, that is, between the content of macerals of the inertinite group in coal and content of macerals of the huminite/vitrinite group. The obtained results suggest that the spontaneous combustion tendency of coal increases with the increasing content of semifusinite and liptinite.

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Authors and Affiliations

Barbara Bielowicz
ORCID: ORCID
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Abstract

In this study, a SYBR Green-based real-time quantitative polymerase chain reaction (qPCR) assay was developed for rapid detection of porcine parvovirus (PPV) 6. Primer pairs targeting the conserved regions of PPV6 Capsid gene were designed. Sensitivity analyses revealed the lowest detection limit of the SYBR Green-based real-time PCR assay to be 47.8 copies/μL, which indicated it was 1000 times higher than that found in the conventional PCR investigations. This assay was specific and showed no cross-species amplification with other six porcine viruses. The assay demonstrated high repeatability and reproducibility; the intra- and inter-assay coefficients of variation were 0.79% and 0.42%, respectively. The positive detection rates of 180 clinical samples with SYBR Green-based real-time PCR and conventional PCR were 12.22% (22/180) and 4.44% (8/180), respectively. Our method is sensitive, specific, and reproducible. The use of SYBR Green-based real-time PCR may be suitable for the clinical detection and epidemiological investigation of PPV6.

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Authors and Affiliations

P. Sun
C.X. Bai
D. Zhang
J. Wang
K.K. Yang
B.Z. Cheng
Y.D. Li
Y. Wang
ORCID: ORCID
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Abstract

Atopic dermatitis (AD) is the most frequent allergic disease in dogs. AD can be treated using allergenspecific immunotherapy as well as symptomatic antipruritic treatment including the use of lokivetmab - caninized anti-interleukine-31 antibody.

The aim of the study was to evaluate the effectiveness of lokivetmab over 12 weeks of treatment. Studies have been carried out in 89 dogs. In all affected animals, the severity of lesions was assessed using the CADESI 04 and the pruritus was assessed using the VAS.

After the first dose of lokivetmab, both CADESI 04 and VAS statistical decreased by 4 weeks from 40.48 to 20.31, and from 7.42 to 2.48, respectively (p = 0.0000001) maintained significantly decresed values during the whole treatment period (CADESI 04 15.64, 15.07 after 8 and 12 weeks, respectively, PVAS 2.03, 1.95 after 8 and 12 weeks, respectively).

Lokivetmab leads to a significant reduction of CADESI 04 and pruritus, within four weeks and maximum effect is achived after the second dose.

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Authors and Affiliations

M.P. Szczepanik
J. Popiel
A. Cekiera
D. Pomorska-Handwerker
J. Karaś-Tęcza
M. Ściskalska
K. Oczkowska
M. Taube
V. Olender
P. Parys
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Abstract

Different approaches to enhance healing of hard or soft tissues include the use of cytokines and growth factors to modify cellular behaviour. Numerous growth factors are found in autologous blood concentrates – platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). Enamel matrix derivative (EMD) may improve tissue healing via amelogenins. Bilayered collagen matrix (CM) is used for soft tissue augmentation.

The aim of the present study was to assess potential benefits of PRP, PRF and EMD in combination with bilayered collagen matrix or CM alone in treatment of oral mucosal defects in rabbits.

Twenty-seven New Zealand white rabbits were included in this randomized controlled trial. Artificial oral mucosal defects were treated with one of these five approaches: PRP+CM, PRF+CM, EMD+CM, CM alone, or left untreated as a negative control - CO. The animals were euthanized 1 day, 7 days, or 28 days after surgery and necropsies were harvested. Histological and molecular biological analyses were performed.

All defects were healed by day 28. No differences between PRP+CM, PRF+CM, CM alone and CO groups were recorded at any time point. Slower angiogenesis and a higher presence of inflammatory infiltrate were observed in the EMD+CM group 28 days after surgery. Molecular biological analyses did not reveal any statistically significant changes.

In conclusion, no improvement in mucosal healing of wounds covered with a collagen membrane and PRP, PRF, or EMD was observed, compared with CM alone or untreated controls.

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Authors and Affiliations

J. Vokurka
F. Hromcik
M. Faldyna
E. Gopfert
M. Vicenova
L. Pozarova
L. Izakovicova Holla
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Abstract

The aim of the present study was to determine changes in oxidative status in plasma of sows during periparturient period using markers of lipid and protein peroxidation intensity. Plasma from 12 pregnant gilts collected on days 14 and 1 before parturition and on days 1, 7 and 14 postpartum was used in the study. As indicators of alterations in the oxidative status, plasma concentrations of thiobarbituric acid reactive substances (TBARS) and sulphydryl groups (SH groups) were measured spectrophotometrically, as well as plasma concentrations of bityrosine and formylokinurenine were determined by the spectrofluorimetric method. Compared to the 14th day antepartum, the concentration of TBARS increased significantly on day 1 postpartum and then decreased significantly on days 7 and 14 after parturition. The concentration of SH groups increased significantly on the last day before parturition and decreased significantly on day 14 postpartum. The concentration of bityrosine increased significantly on the last day before parturition and decreased significantly on days 7 and 14 postpartum. The concentration of formylokinurenine increased significantly on the last day before parturition, remained at this level on the first day after parturition and then decreased slightly on days 7 and 14 postpartum. These results indicate that during periparturient period in sows, especially around the parturition, the oxidative/antioxidative balance is disturbed, which leads to oxidative stress. Considering that oxidative stress is potentially harmful for mothers and neonates, this may be an important factor in the increased risk of diseases occurring during this period.

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Authors and Affiliations

M. Szczubiał
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Abstract

Herpesviruses (HV) are pathogens causing infections in humans and animals worldwide. Since it shares many common features with other HV, bovine HV type 1 (BoHV-1) was selected as a model to test the anti-herpesviral activity of medicinal plants.

Fifteen plants were chosen in this study for their medical, antibacterial and antiviral properties. The aim was to investigate ethanolic extracts from the selected medicinal plants for anti-BoHV-1 activity. The virucidal activities were evaluated by comparing the effect of noncytotoxic concentrations of extracts on BoHV-1 strain 1640 replication in Madin-Darby bovine kidney (MDBK) cells. Virucidal activity was determined by means of virus titration after exposure to the extracts. The extract of Desmodium canadense was found to be the most effective virucide – the 50% tissue culture infective dose (TCID50) after exposure was 3.75 log10 and the virus reduction factor was ≥5.0±0.25 log10. The extract of D. canadense was therefore chosen for further studies. Virus yield reduction assays showed that D. canadense extract had time-dependent and dose-dependent effects. It effectively reduced virus titre from 8.33 log10 to 4.67 log10 (p<0.01). The virucidal activity was also confirmed by real-time polymerase chain reaction (real-time PCR), where the number of threshold cycles (Ct) was inversely proportional to the virus titre in TCID50 The virucidal activity was also confirmed by real-time polymerase chain reaction (real-time PCR). This method showed that the number of threshold cycles (Ct) was inversely proportional to the virus titre (direct correlation with exposure time R=0.9321). The extract of D. canadense showed a high virus reduction capacity. In future, such active substances should be identified for the development of effective antivirals.

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Authors and Affiliations

R. Lelešius
P. Girdauskaitė
A. Karpovaitė
R. Mickienė
T. Drevinskas
N. Tiso
O. Ragažinskienė
L. Kubilienė
A. Maruška
A. Šalomskas
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Abstract

Conventional methods for determining the reproductive performance of sheep bred either after estrus synchronization during the breeding season or after induction of estrus/ovulation during the non-breeding season take a long time and may give misleading results due to the effect of environmental factors. Laparoscopic observations allow real-time monitoring of ovarian activity around estrus or ovulation. This study was aimed at assessing the superovulatory effects of follicle-stimulating hormone (FSH) and equine chorionic gonadotropin (eCG) treatments by laparoscopy during breeding (September-November, n=12) and non-breeding (April-June, n=12) seasons in Akkaraman sheep. In both seasons, after CIDR withdrawal, the ewes were injected either with 600 IU eCG or 300 μl (20 mg/ml) FSH twice at 12 hour intervals. Plasma P4, E2 and LH concentrations were determined at the time of intra-vaginal CIDR insertion (day 0) and then at its withdrawal (day 12), followed by 3 and 6 days of eCG or FSH injections. After 3 (first observation) and 6 (second observation) days of hormone injections, laparoscopy was performed to record ovarian activity in both seasons. The eCG increased (p<0.05) the numbers of large follicles (first observation) and CL (first and second observations) in the breeding season compared to FSH treatment. CL, small-moderate and large follicle numbers of eCG treated ewes were higher (p<0.05) than those of FSH at both observations in the non-breeding season. In the breeding season, eCG treated ewes had higher (p<0.05) plasma P4 (3 and 6 days after hormones injections) and E2 (3 days after hormones injections) concentrations than those of FSH. In conclusion, the results of the present study indicate that treatment with eCG during the non-breeding season can support ovarian activity, and thus increase ovulation rate and plasma hormone concentrations around induced estrus/ovulation in Akkaraman ewes.

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Authors and Affiliations

U. Şen
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Abstract

The aim of the study was to compare the effects of corneal healing in case of application of stem cells in various forms, in relation to the antibiotic-assisted procedures. Rabbits were divided into 4 groups in the first stage of the experiment. Group 0 (negative control group) was not subjected to any actions, which would cause damage to the cornea. The remaining three groups had their cornea damaged. Group 1 (positive control group) – no drugs were administered during the experiment. Rabbits in group 2 were administered with ointment containing stem cells to the lesion, while group 3 – with ofloxacinum. The stem cells were administered during the first five days, twice a day, onto the corneal surface. The further course of the experiment consisted of observing the rate of healing of the injured cornea and assessment of its transparency, size of lesion, hyperaemia, eyelid spasm and outflow from the conjunctival sac after 5, 10 and 20 days.

In the second stage the animals were euthanised after clinical examination on the twentieth day of the experiment, in order to analyse the corneal reparative processes on the same day. The studies revealed that the application of antlerogenic stem cells had a positive effect on the healing process of corneal defects. The application thereof not only shortened the healing time, but also weakened or arrested the development of side effects. The results have demonstrated that the epithelial proliferation in each group was different. The longest was maintained in the group with stem cells, the shortest – in the group with chemotherapeutics. The use of antlerogenic stem cells had a positive effect on the healing process of corneal lesions. The use of stem cells helped to maintain high transparency of the cornea.

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Authors and Affiliations

M. Kiełbowicz
P. Kuropka
M. Cegielski
Z. Kiełbowicz
P. Trębacz
M. Hebel
R. Aleksiewicz
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Abstract

In the present study, the influence of the infection with equine herpesvirus type 1 (non-neuropathogenic and neuropathogenic strains of EHV-1) on the morphology and distribution of mitochondrial network in equine dermal cell line was investigated. Our results indicate that EHV-1-infection caused changes in the mitochondrial morphology manifested mostly by fission and reactive oxygen species generation.

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Authors and Affiliations

M. Bartak
M. Chodkowski
A. Słońska
M.W. Bańbura
J. Cymerys

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