54 research outputs found

    Problems of Hydraulic Conductivity Estimation in Clayey Karst Soils

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    Even in karst areas, considerably thick soils can be found in accumulation zones. Here, the degree of groundwater vulnerability depends not only on the thickness, but also on the hydraulic conductivity and retention properties of the soil cover. The hydraulic conductivity of fine-grained karst soils from Slovakia, Croatia and Austria was studied within several international research projects, by the application of four different test methods. Results are discussed from different points of view. Triaxial tests yielded a very broad interval between the maximum and minimum hydraulic conductivity (from 5.83x10-7 m.s-1 to 3.50x10-11 m.s-1), therefore the mean value cannot be used in any calculations. The consolidometer method gave lower values in general, between 9.40x10-10 m.s-1 to 3.59x10-8 m.s-1. However, this method overestimates the soil “impermeability”. Estimates based on grain size are unsuitable, as fine-grained soils did not fulfil the random conditions of known formula. Finally, the “in situ” hydraulic conductivity was measured using a Guelph permeameter. As expected, “in situ” tests showed 100 to 1000-times higher kf than the laboratory tests. This method best reflects the real conditions. Therefore, only this type of data should be considered in any environmental modelling. In a soil profile, hydraulic conductivity depends on the mineral composition, depth, secondary compaction, etc. The degree and duration of saturation with water is very important for young soils containing smectite. Their hydraulic conductivity might be very low when saturated for long time, but also very high, when open desiccation cracks occur. A very slight trend was found, but only in Slovak soils, showing a decrease in the hydraulic conductivity with increasing content of the clay fraction <0.002 mm. These results should contribute to a better estimate of the protective role of soils in groundwater vulnerability maps

    Dysregulation of epicardial adipose tissue in cachexia due to heart failure. the role of natriuretic peptides and cardiolipin

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    Background: Cachexia worsens long-term prognosis of patients with heart failure (HF). Effective treatment of cachexia is missing. We seek to characterize mechanisms of cachexia in adipose tissue, which could serve as novel targets for the treatment. Methods: The study was conducted in advanced HF patients (n&nbsp;=&nbsp;52; 83% male patients) undergoing heart transplantation. Patients with ≥7.5% non-intentional body weight (BW) loss during the last 6&nbsp;months were rated cachectic. Clinical characteristics and circulating markers were compared between cachectic (n&nbsp;=&nbsp;17) and the remaining, BW-stable patients. In epicardial adipose tissue (EAT), expression of selected genes was evaluated, and a combined metabolomic/lipidomic analysis was performed to assess (i) the role of adipose tissue metabolism in the development of cachexia and (ii) potential impact of cachexia-associated changes on EAT-myocardium environment. Results: Cachectic vs. BW-stable patients had higher plasma levels of natriuretic peptide B (BNP; 2007&nbsp;±&nbsp;1229 vs. 1411&nbsp;±&nbsp;1272&nbsp;pg/mL; P&nbsp;=&nbsp;0.010) and lower EAT thickness (2.1&nbsp;±&nbsp;0.8 vs. 2.9&nbsp;±&nbsp;1.4&nbsp;mm; P&nbsp;=&nbsp;0.010), and they were treated with ~2.5-fold lower dose of both β-blockers and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACE/ARB-inhibitors). The overall pattern of EAT gene expression suggested simultaneous activation of lipolysis and lipogenesis in cachexia. Lower ratio between expression levels of natriuretic peptide receptors C and A was observed in cachectic vs. BW-stable patients (0.47 vs. 1.30), supporting activation of EAT lipolysis by natriuretic peptides. Fundamental differences in metabolome/lipidome between BW-stable and cachectic patients were found. Mitochondrial phospholipid cardiolipin (CL), specifically the least abundant CL 70:6 species (containing C16:1, C18:1, and C18:2 acyls), was the most discriminating analyte (partial least squares discriminant analysis; variable importance in projection score&nbsp;=&nbsp;4). Its EAT levels were higher in cachectic as compared with BW-stable patients and correlated with the degree of BW loss during the last 6&nbsp;months (r&nbsp;=&nbsp;−0.94; P&nbsp;=&nbsp;0.036). Conclusions: Our results suggest that (i) BNP signalling contributes to changes in EAT metabolism in cardiac cachexia and (ii) maintenance of stable BW and ‘healthy’ EAT-myocardium microenvironment depends on the ability to tolerate higher doses of both ACE/ARB inhibitors and β-adrenergic blockers. In line with preclinical studies, we show for the first time in humans the association of cachexia with increased adipose tissue levels of CL. Specifically, CL 70:6 could precipitate wasting of adipose tissue, and thus, it could represent a therapeutic target to ameliorate cachexia

    Pregnancy and Fetal Outcomes After Exposure to Mefloquine in the Pre- and Periconception Period and During Pregnancy

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    Pregnant women who travel to malarious areas and their clinicians need data on the safety of malaria chemoprophylaxis. The drug safety database analysis of mefloquine exposure in pregnancy showed that the birth defect prevalence and fetal loss in maternal, prospectively-monitored cases were comparable to background rates

    Municipal solid waste management under Covid-19: Challenges and recommendations

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    Covid-19 is proving to be an unprecedented disaster for human health, social contacts and the economy worldwide. It is evident that SARS-CoV-2 may spread through municipal solid waste (MSW), if collected, bagged, handled, transported or disposed of inappropriately. Under the stress placed by the current pandemic on the sanitary performance across all MSW management (MSWM) chains, this industry needs to re-examine its infrastructure resilience with respect to all processes, from waste identification, classification, collection, separation, storage, transportation, recycling, treatment and disposal. The current paper provides an overview of the severe challenges placed by Covid-19 onto MSW systems, highlighting the essential role of waste management in public health protection during the ongoing pandemic. It also discusses the measures issued by various international organisations and countries for the protection of MSWM employees (MSWEs), identifying gaps, especially for developing countries, where personal protection equipment and clear guidelines to MSWEs may not have been provided, and the general public may not be well informed. In countries with high recycling rates of MSW, the need to protect MSWEs' health has affected the supply stream of the recycling industry. The article concludes with recommendations for the MSW industry operating under public health crisis conditions

    Potential impact of two landfills on the near vicinity with the use of bioindicators

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    The research deals in complex with the issue of landfilling and with a possible use of biological indicators to assess the impact of landfill on its surroundings. The problem is topical as landfilling remains the most spread technology for the disposal of communal waste in the Czech Republic. Assessing the impact of the landfill on its environs, we based our study on the selected bioindicators present in 1995 and in 2007 – 2010. During the period of vegetation biomonitoring, we did not detect any significant impact of the landfills on the biotic composition of the environment and no symptoms of leaf area chlorosis or necrosis that would have indicated the direct impact of sanitary landfills operation on the locality. The Štěpánovice landfill and Kuchyňky landfill have a functional system of drains combined with the system of ground sealing and the system of seepage water drainage pits. It further has a sophisticated system to check fencing, fly-offs and to collect lightweight waste. Both landfills are constructed and operated in compliance with the most modern and strictest requirements and standards

    Testing the biodegradability and biodegradation rates of degradable/biodegradable plastics within simulated environment

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    The objective of this study was to evaluate and compare the biodegradability and biodegradation rates of ‘single-use' plastic bags available on the market and labeled as degradable/biodegradable. The test was carried out under both aerobic and anaerobic conditions. The project length was 20 months. The biodegradation results in the laboratory conditions demonstrate that none of the degradable/ biodegradable bags showed visual changes and/or were broken into pieces and none of them experienced any disintegration or degradation. The cellulose filter paper (CFP) completely degraded after 10 days in the aerobic conditions and after 5 month in the anaerobic conditions, implying that the conditions required for biodegradation to occur in a sampling environment were present

    Disposal of unused tires in the Czech Republic

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    W ostatnich latach, z powodu szybkiego rozwoju społeczeństwa, rośnie popyt na opony. Wiąże się to ze wzrostem produkcji zużytych opon. Jednym z głównych problemów, związanch ze zużytymi oponami, jest znalezienie odpowiedniego sposobu ich unieszkodliwiania. Unieszkodliwianie zużytych opon powinno być w zgodzie z zasadą zrównoważonego rozwoju. Oznacza to, że produkcyjnie i energetycznie wymagające produkty muszą być po ukończeniu swojej żywotności w 100% recyklowane, a uzyskane w ten sposób komponenty ponownie wykorzystane. Niniejsza praca zajmuje się problematyką zużytych opon jako cennego surowca. Celem pracy jest opisanie sytuacji unieszkodliwiania zużytych opon w Republice Czeskiej, w Unii Europejskiej (dalej EU – od roku 2004 w 25 krajach członkowskich, od roku 2007 w 27 krajach członkowskich) oraz na świecie. W dalszej części praca dotyczy problematyki wtórnego odbioru zużytych opon w Republice Czeskiej.The worldwide production of waste tires (so called "end of life tires" - ELT) grows every year. The same situation is in the Czech Republic and in the countries of the European Union, but also in the world. Every year about 3.4 million tonnes of used tyres (part worn + end of life tyres) are generated in Europe, of which 3 million tonnes are either recycled or recovered. This amounts to approximately 300 million units. The composition and energy characteristics of tires are a significant source of material, energy and also raw material. Calorific value tires ranges from approximately 25 to approximately 32 MJ · kg-1. The calorific value is comparable with conventional fossil fuels, which is due to the high proportion of hydrocarbons (over 75%). For these reasons, an alternative tire conventional fuels. The aim of the research is focused on the second part of product life cycle – the tire at the end of lifetime. The main possibilities of utilization of used up tires after end of their life are as follows: retreading, recycling (production of granulate), energy and material utilization in a cement factory, pyrolysis (production of pyrolytic products) and formerly used waste storing. Another objective of the work is to describe the situation of waste tires in the Czech Republic in the European Union and the world and focus on the issue of return

    Research of the biodegradability of degradable/biodegradable plastic material in various types of environments

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    Research of the biodegradability of degradable/biodegradable plastic material in various types of environments. Research was carried out in order to assess biodegradability of degradable/biodegradable materials made of HDPE and mixed with totally degradable plastic additive (TDPA additive) or made of polyethylene (PE) with the addition of pro-oxidant additive (d2w additive), advertised as 100% degradable or certified as compostable within various types of environments. Research conditions were: (i) controlled composting environment – laboratory-scale, (ii) real composting conditions – domestic compost bin, (iii) real composting conditions – industrial composting plant and (iv) landfill conditions. The results demonstrate that the materials made of HDPE and mixed with totally degradable plastic additive (TDPA additive) or made of polyethylene (PE) with the addition of pro- -oxidant additive (d2w additive) or advertised as 100% degradable did not biodegrade in any of the above-described conditions and remained completely intact at the end of the tests. Biodegradation of the certified compostable plastic bags proceeded very well in laboratory-scale conditions and in real composting conditions – industrial composting plant, however, these materials did not biodegrade in real composting conditions – domestic compost bin and landfill conditions
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