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  • Author: Anna Kowalik x
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Removal of Cr(III) ions from salt solution by nanofiltration: experimental and modelling analysis

Abstract

The aim of this study was experimental and modelling analysis of the nanofiltration process used for the removal of chromium(III) ions from salt solution characterized by low pH. The experimental results were interpreted with Donnan and Steric Partitioning Pore (DSP) model based on the extended Nernst-Planck equation. In this model, one of the main parameters, describing retention of ions by the membrane, is pore dielectric constant. In this work, it was identified for various process pressures and feed compositions. The obtained results showed the satisfactory agreement between the experimental and modelling data. It means that the DSP model may be helpful for the monitoring of nanofiltration process applied for treatment of chromium tannery wastewater.

Open access
Measurements of doses from photon beam irradiation and scattered neutrons in an anthropomorphic phantom model of prostate cancer: a comparison between 3DCRT, IMRT and tomotherapy

Abstract

Introduction. The rapid development of new radiotherapy technologies, such as intensity modulated radiotherapy (IMRT) or tomotherapy, has resulted in the capacity to deliver a more homogenous dose in the target. However, the higher doses associated with these techniques are a reason for concern because they may increase the dose outside the target. In the present study, we compared 3DCRT, IMRT and tomotherapy to assess the doses to organs at risk (OARs) resulting from photon beam irradiation and scattered neutrons.

Material and methods. The doses to OARs outside the target were measured in an anthropomorphic Alderson phantom using thermoluminescence detectors (TLD 100) 6Li (7.5%) and 7Li (92.5%). The neutron fluence rate [cm−2·s−1] at chosen points inside the phantom was measured with gold foils (0.5 cm diameter, mean surface density of 0.108 g/cm3).

Results. The doses [Gy] delivered to the OARs for 3DCRT, IMRT and tomotherapy respectively, were as follows: thyroid gland (0.62 ± 0.001 vs. 2.88 ± 0.004 vs. 0.58 ± 0.003); lung (0.99 ± 0.003 vs. 4.78 ± 0.006 vs. 0.67 ± 0.003); bladder (80.61 ± 0.054 vs. 53.75 ± 0.070 vs. 34.71 ± 0.059); and testes (4.38 ± 0.017 vs. 6.48 ± 0.013 vs. 4.39 ± 0.020). The neutron dose from 20 MV X-ray beam accounted for 0.5% of the therapeutic dose prescribed in the PTV. The further from the field edge the higher the contribution of this secondary radiation dose (from 8% to ~45%).

Conclusion. For tomotherapy, all OARs outside the therapeutic field are well-spared. In contrast, IMRT achieved better sparing than 3DCRT only in the bladder. The photoneutron dose from the use of high-energy X-ray beam constituted a notable portion (0.5%) of the therapeutic dose prescribed to the PTV.

Open access
Endoparasites of the European beaver (Castor fiber L. 1758) in north-eastern Poland

Abstract

Parasitological examination after necropsies of 48 European beavers from Podlaskie and Warmisko-Mazurskie provinces were performed between April 2011 and November 2012. All helminthes were isolated from the contents of the gastro-intestinal tract and their species were determined. In addition, blood samples and faeces were examined. All beavers were infected with six species of parasites. Stichorchis subtriqetrus trematodes were found in 93.7% of animals. They were localized mainly in the caecum, less in the colon, and single juvenile parasites were found in the small intestine. The intensity of infection ranged from two to 893 parasites. Travassosius rufus nematodes (10-4336 specimens) were present in the stomach of 68.7% of the beavers. In the small intestine of four (8.3%) beavers, two-six specimens of Psilotrema castoris were found. This is the first record of this species in Poland and the third of its discovery in the world. Furthermore, in the small intestine of one beaver, two Trichostrongylus capricola nematodes were detected. In the liver of one beaver, pathological changes caused by hydatid cestode Echinococus granulosus occurred. Inflammatory changes of the gastric mucosa caused by Travassosius rufus and of caecum caused by Stichorchis subtriquertus, were observed. Coproscopy was performed with the use of Baermann, flotation, and decantation methods. All results of Baermann method were negative. Examinations with flotation and decantation methods confirmed necropsy findings. Using the flotation method, single oocysts of Eimeria sprehni in one beaver were detected. A blood test conducted by Kingston and Morton method did not reveal the presence of protozoa or microfilariae.

Open access
Carcinogenesis induced by low-dose radiation

Abstract

Background

Although the effects of high dose radiation on human cells and tissues are relatively well defined, there is no consensus regarding the effects of low and very low radiation doses on the organism. Ionizing radiation has been shown to induce gene mutations and chromosome aberrations which are known to be involved in the process of carcinogenesis. The induction of secondary cancers is a challenging long-term side effect in oncologic patients treated with radiation. Medical sources of radiation like intensity modulated radiotherapy used in cancer treatment and computed tomography used in diagnostics, deliver very low doses of radiation to large volumes of healthy tissue, which might contribute to increased cancer rates in long surviving patients and in the general population. Research shows that because of the phenomena characteristic for low dose radiation the risk of cancer induction from exposure of healthy tissues to low dose radiation can be greater than the risk calculated from linear no-threshold model. Epidemiological data collected from radiation workers and atomic bomb survivors confirms that exposure to low dose radiation can contribute to increased cancer risk and also that the risk might correlate with the age at exposure.

Conclusions

Understanding the molecular mechanisms of response to low dose radiation is crucial for the proper evaluation of risks and benefits that stem from these exposures and should be considered in the radiotherapy treatment planning and in determining the allowed occupational exposures.

Open access
The influence of dietary replacement of soybean meal with high-tannin faba beans on gut-bone axis and metabolic response in broiler chickens

Abstract

Faba bean (FB) seeds can be a good protein-energy component in animal feed. However, the presence of anti-nutritional substances is a negative feature of FB seeds. The aim of this study was to examine the influence of different levels of unprocessed FB seeds in feed on the gut-bone axis and metabolic profile in broilers. Ninety six, 1-day-old Ross 308 broiler chickens were randomly selected to one of the 3 dietary treatments (32 chickens in each, divided into 8 pens with 4 birds per each pen): the control group fed standard diet with soybean meal and without FB seeds, group I fed 8/15% (starter/grower) of high-tannin FB seeds, and group II fed 16/22% of high-tannin FB seeds. Bone mechanical examination, hematological and serum biochemical analysis as well histomorphometry of small intestine and liver tissue were performed. The intake of high-tannin FB seeds, irrespective of their amount, did not alter the bone geometric, mechanical and densitometric parameters nor influenced basal hematological parameters, however it resulted in: decreased serum concentration of total cholesterol and calcium; a reduced longitudinal myenteron of small intestine; increased mucosa and villus epithelium thickness, villus length, thickness and absorptive surface in duodenum; increased number of active crypts in jejunum; unchanged collagen area, intercellular space, and total cell number in the liver; decreased number of multinuclear hepatocyte cells. Moreover, the livers of birds fed the higher dose of high-tannin FB seeds had lymphocytic infiltrates in portal tracts and sinusoids. Feeding of unprocessed high-tannin FB seeds exerted an influence on the gastrointestinal tract by increased absorptive surface. In conclusion, the dietary inclusion of unprocessed high-tannin FB seeds had no negative effects on broiler growth, tibial bone mechanical properties and intestinal characteristics. Unprocessed high-tannin FB seeds may be used in broiler diets, but their dietary levels should not be higher than those discussed.

Open access