Applied Radiation Dose Research Articles

Gamma Radiation Induced Contraction of Alkyne Modified Polymer Hydrogels

AbstractGamma radiation triggered secondary crosslinking of dextran hydrogels leads to macroscopic hydrogel contraction. The authors use stable polymer hydrogels, prepared through azide‐alkyne crosslinking, containing surplus alkyne groups. γ‐irradiation of these gels leads to more alkyne crosslinking, enabling controlled increase of crosslink density, which in turn leads to an increase of hydrogel stiffness and macroscopic hydrogel contraction. Gel contraction scales linearly with the applied radiation dose. The same mechanism is applied to achieve γ‐radiation triggered release of the small molecule cargo, akin to wringing out a sponge. γ‐irradiation of touching hydrogel objects leads to gel fusion and the formation of a self‐supporting gel connection, demonstrating the reactivity of the excess alkyne groups. They envision applications in gel gluing and the construction of complex gel architectures, as well as in responsive materials for controlled release.

EPR analysis of the dosimetric properties of sulfamic acid irradiated by different ionizing radiations for radiotherapy and hadrontherapy applications

In this work we analyze the dosimetric properties of sulfamic acid irradiated by X-rays photons (6MV and 18MV), electrons (6 MeV and 18 MeV), protons (68 MeV) and neutrons (from 0 to 400 MeV). After irradiation, the samples are analyzed by Electronic Paramagnetic Resonance “EPR” to measure the applied radiation dose. For all used irradiations, the obtained results show that the measurable threshold dose is 0.25 Gy. The correlation between measured dose and EPR signal is linear in the dose range from 0 to 20 Gy with a correlation coefficient above 0.999. Sulfamic acid seems to be more sensitive to photons and electrons irradiations (approximately 20% more sensitive) than to protons and neutrons irradiations. The overall uncertainty (2σ) of dose monitoring is approximately 6% by peak to peak method and 5% by double Integration method. The time dependence indicates a low fading effect during the storage period (4% of fading after two months of storage). These results prove that sulfamic acid is a promising dosimeter for use in the field of radiotherapy including hadrontherapy, These results prove that sulfamic acid is a promising dosimeter for use in the field of radiotherapy including hadrontherapy, in particular for small field treatment and out off-field dose estimation.

Morphological changes after cranial fractionated photon radiotherapy: Localized loss of white matter and grey matter volume with increasing dose

PurposeNumerous brain MR imaging studies have been performed to understand radiation-induced cognitive decline. However, many of them focus on a single region of interest, e.g. cerebral cortex or hippocampus. In this study, we use deformation-based morphometry (DBM) and voxel-based morphometry (VBM) to measure the morphological changes in patients receiving fractionated photon RT, and relate these to the dose. Additionally, we study tissue specific volume changes in white matter (WM), grey matter (GM), cerebrospinal fluid and total intracranial volume (TIV). Methods and materialsFrom our database, we selected 28 patients with MRI of high quality available at baseline and 1 year after RT. Scans were rigidly registered to each other, and to the planning CT and dose file. We used DBM to study non-tissue-specific volumetric changes, and VBM to study volume loss in grey matter. Observed changes were then related to the applied radiation dose (in EQD2). Additionally, brain tissue was segmented into WM, GM and cerebrospinal fluid, and changes in these volumes and TIV were tested. ResultsPerforming DBM resulted in clusters of dose-dependent volume loss 1 year after RT seen throughout the brain. Both WM and GM were affected; within the latter both cerebral cortex and subcortical nuclei show volume loss. Volume loss rates ranging from 5.3 to 15.3%/30 Gy were seen in the cerebral cortical regions in which more than 40% of voxels were affected. In VBM, similar loss rates were seen in the cortex and nuclei. The total volume of WM and GM significantly decreased with rates of 5.8% and 2.1%, while TIV remained unchanged as expected. ConclusionsRadiotherapy is associated with dose-dependent intracranial morphological changes throughout the entire brain. Therefore, we will consider to revise sparing of organs at risk based on future cognitive and neurofunctional data.

Brachytherapy for Peripheral Retinal Capillary Haemangioblastoma in von Hippel-Lindau Disease.

To report our experience with 106ruthenium-brachytherapy of peripheral capillary haemangioblastomas in patients with von Hippel-Lindau disease. Retrospective case series. A total of 53 haemangioblastomas, treated with 106ruthenium-brachytherapy, were included in our study. The applied radiation dose, visual outcome, angioma activity, need for vitreoretinal surgery and incidence of secondary complications such as macular oedema, secondary glaucoma, vitreous haemorrhage, and epiretinal gliosis were assessed. All treated eyes could be preserved. In 11 patients (20.8%), single brachytherapy did not achieve complete inactivation of the tumour. 31% developed macular oedema postoperatively. Tractional retinal detachment developed in 23.8%, and epiretinal gliosis was observed in 2.4% of patients. Vitreoretinal surgery was necessary in 50% of all treated eyes. At the end of the follow-up, 40.5% of all treated eyes achieved visual acuity (VA) of 0.6 or better, and one third reached a VA of less than 0.1. Mean irradiation dose to the tumour apex was 144 Gy. Higher apex doses correlated with better tumour control of irradiated haemanigoblastomas and lower complication rates. Brachytherapy of peripheral retinal capillary haemangioblastomas is an effective treatment modality. Higher irradiation doses seem to lead to more successful treatment.

Evaluation of Diagnostic Accuracy and Radiation Exposure of Dual-Energy Computed Tomography (DECT) in the Course of Chronic Thromboembolic Pulmonary Hypertension (CTEPH).

The purpose of this study was to assess the diagnostic accuracy of computed tomography pulmonary angiogram (CTPA) including dual energy and reconstruction of iodine maps for diagnosing CTEPH. This method for detecting embolisms and perfusion failures was compared with V/Q-SPECT. An additional purpose was to compare the applied radiation dose of both techniques. 71 patients (49 women) with suspected CTEPH were included in this prospective study. The patients received a V/Q-SPECT and a dual-energy CTPA. Iodine maps were reconstructed from the data set. CTPA and the iodine maps were read by an experienced radiologist unaware of the clinical information as well as the results of the V/Q-SPECT. Results were compared to the V/Q-SPECT. DLP and the applied amount of radionuclides (MAA, Technegas) were obtained for comparison of radiation dose. For the diagnosis of CTEPH, the sensitivity of DECT was 1.000, specificity 0.966, PPV 0.867 and NPV 1.000, respectively. There was not a considerable difference in the x-ray exposure between the DECT examination and the V/Q-SPECT (1.892 mSv vs. 1.911 mSv; p = 0.6115). Both examination modalities were highly consistent regarding the classification of pathological segments (1177/1278 segments, 92,09 %, κ = 0,5938). This study presents the DECT, in combination with reconstructed iodine maps, as a potential alternative to the current imaging technique of first choice, V/Q-SPECT. For creating future prospective diagnostic algorithms, the implementation of DECT screening with iodine maps should be considered. · DECT correctly identified all CTEPH patients.. · There is substantial agreement between DECT and V/Q-SPECT in the classification of pathological segments.. · There is no significant difference in radiation exposure during DECT examination and V/Q-SPECT examination.. · Reduced radiation dose does not negatively impact image quality.. · Schüßler A, Richter M, Tello K et al. Evaluation der diagnostischen Genauigkeit und der Strahlendosis der Dual-Energy-Computertomografie (DECT) bei chronisch thromboembolischer pulmonaler Hypertonie (CTEPH). Fortschr Röntgenstr 2021; 193: 1318 - 1326.

Fast photocatalytic polypropylene degradation by nanostructured bismuth catalysts

Every year millions of tons of polymeric waste are discarded by human activities due to its low production cost; the landfills are littered with plastic waste without any recycling value. This class of garbage exhibits a very low degradation rate under environmental conditions, occupying a lot of space in landfills for a long time, which is costly for society and harmful to environment. Photocatalysis has become a quite interesting tool to oxidize organic pollutants as dyes, drugs, and some polymers, representing a potential alternative for reducing the environmental pollution. In this work, we report an ecofriendly method for polypropylene (PP) degradation by catalytic bismuth nanoparticles (Bi2O3 or BiFeO3) assisted by ionizing radiation. The effect of catalyst load and applied radiation dose on photo-degradation rate were studied. High oxidation efficiencies were detected even at both low catalyst load nd irradiation dose. Oxidized propylene was detected by infrared spectroscopy (FTIR-ATR), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (SEM-EDS). All those instrumental techniques confirmed the successful oxidation of PP in few hours of reaction and 1% weight of the catalyst. 2,3 butane-dione, 4-hydroxy-4-methyl pentane-2-one, and ethyl-9-acetoxynonanoate were the main degradation products identified mainly by nuclear magnetic resonance (NMR 1H, 13C).

Chemical Composition of Magonia pubescens Essential Oils and Gamma-Radiation Effects on Its Constituents and Cytotoxic Activity in Leukemia and Breast Cancer Model.

Magonia pubescens A. St.-Hil. is a Brazilian species often used in ethnopharmacology for wound and pain healing and seborrhea treatment. For the first time, essential oils (EOs) obtained from M. pubescens inflorescences were studied. The plant materials (Montes Claros, Brazil, 2018) were submitted to different gamma-radiation doses and their chemical compositions were analyzed by GC/MS and GC-FID. The cytotoxic activity of the EOs was evaluated against K562 and MDA-MB-231 cancer cell lines. A total of 30 components were identified, being 24 compounds detected for the first time in M. pubescens. The main obtained components were hotrienol (35.9 %), cis-linalool oxide (17.0 %) and trans-linalool oxide (10.2 %). The chemical composition of the EO was slightly affected by the applied radiation doses. Irradiated and non-irradiated EOs showed cytotoxic activity against both cell lines and the non-irradiated EO sample was the most active against the K562 cell lines (IC50 =22.10±1.98).

X-ray Radiation Effects on SWCNT/PMMA Thin Film Nanocomposites

This paper studies the response of a radiation sensor that was developed from single-walled carbon nanotube (SWCNT) and poly (methyl methacrylate) (PMMA) nanocomposite thin films placed on an interdigitated electrode (IDE). We studied the effects of X-rays in real-time electrical resistance of the thin film nanocomposites. A 160 kV X-ray source irradiated the nanocomposite devices with ionizing X-ray radiation at different doses and dose rates, causing the decrease in resistance of thin film through the production of charge carriers. The embedded SWCNT network helped transport radiation-induced electrons to the electrodes. Pre-irradiation resistance can be obtained rapidly from heat treatment of irradiated nanocomposite devices. It is observed that the required heat treatment time for thin film device recovery increased almost linearly with applied radiation dose. The thin film devices were operated at dc voltage as low as 0.05 V for reliable measurement of the radiation-induced change in electrical resistance. The results of this study suggest that SWCNT/PMMA thin film devices could be used for sensing X-ray radiation, with significantly higher sensitivity than comparable devices made with multi-walled CNT (MWCNT) based nanocomposites in a previous study.

Modelling the Stiffness-Temperature Dependence of Resin-Rubber Blends Cured by High-Energy Electron Beam Radiation Using Global Search Genetic Algorithm.

Modelling the influence of high-energy ionising radiation on the properties of materials with polymeric matrix using advanced artificial intelligence tools plays an important role in the research and development of new materials for various industrial applications. It also applies to effective modification of existing materials based on polymer matrices to achieve the desired properties. In the presented work, the effects of high-energy electron beam radiation with various doses on the dynamic mechanical properties of melamine resin, phenol-formaldehyde resin, and nitrile rubber blend have been studied over a wide temperature range. A new stiffness-temperature model based on Weibull statistics of the secondary bonds breaking during the relaxation transitions has been developed to quantitatively describe changes in the storage modulus with temperature and applied radiation dose until the onset of the temperature of the additional, thermally-induced polymerisation reactions. A global search real-coded genetic algorithm has been successfully applied to optimise the parameters of the developed model by minimising the sum-squared error. An excellent agreement between the modelled and experimental data has been found.

The Influence of Radiation on Bone and Bone Cells-Differential Effects on Osteoclasts and Osteoblasts.

The bone is a complex organ that is dependent on a tight regulation between bone formation by osteoblasts (OBs) and bone resorption by osteoclasts (OCs). These processes can be influenced by environmental factors such as ionizing radiation (IR). In cancer therapy, IR is applied in high doses, leading to detrimental effects on bone, whereas radiation therapy with low doses of IR is applied for chronic degenerative and inflammatory diseases, with a positive impact especially on bone homeostasis. Moreover, the effects of IR are of particular interest in space travel, as astronauts suffer from bone loss due to space radiation and microgravity. This review summarizes the current state of knowledge on the effects of IR on bone with a special focus on the influence on OCs and OBs, as these cells are essential in bone remodeling. In addition, the influence of IR on the bone microenvironment is discussed. In summary, the effects of IR on bone and bone remodeling cells strongly depend on the applied radiation dose, as differential results are provided from in vivo as well as in vitro studies with varying doses of IR. Furthermore, the isolated effects of IR on a single cell type are difficult to determine, as the bone cells and bone microenvironment are building a tightly regulated network, influencing on one another. Therefore, future research is necessary in order to elucidate the influence of different bone cells on the overall radiation-induced effects on bone.

Evaluation of artifacts of cochlear implant electrodes in cone beam computed tomography

PurposeCone Beam Computed Tomography (CBCT) offers a valid alternative to conventional Computed Tomography (CT). A possible radiation dose reduction with the use of CBCT in postoperative imaging of CIs is of great importance. Whether the visualization of Cochlear Implant (CI) electrodes in CBCT correlates with the radiation dose applied was investigated in this study.MethodsWe compared the visualization quality of Contour Advance CIs to Straight CIs from Cochlear using CBCT with varying tube parameters on whole-head specimen.ResultsThe internal diameter of the cochlea decreases from base to apex, resulting in a significantly different intracochlear positioning of the two tested CI models. While electrodes of the Contour Advance series are located close to the modiolus, thus closer to the spiral ganglion neurons, those of the Straight series are located further away. The artifact portion of the electrode amounts to 50–70% of the radiological diameter of the electrode. An increase in artifact portion from the base (electrode #1 approx. 50%) to the apex (electrode #20 approx. 70%) of the cochlea was observed. The visualization of electrodes in the medial and apical part of the cochlea is limited due to artifact overlapping. There was no correlation between the artifact size and the applied radiation dose.ConclusionThe results indicate that a reduction of the radiation dose by up to 45% of the currently applied radiation dose of standard protocols would be possible. Investigations of the effects on subjective image quality still need to be performed.

CT radiation dose reduction in patients with total hip arthroplasties using model-based iterative reconstruction and orthopaedic metal artefact reduction

ObjectiveTo evaluate the impact of radiation dose reduction on image quality in patients with metal-on-metal total hip arthroplasties (THAs) using model-based iterative reconstruction (MBIR) combined with orthopaedic metal artefact reduction (O-MAR).Materials and methodsPatients with metal-on-metal THAs received a pelvic CT with a full (FD) and a reduced radiation dose (RD) with −20%, −40%, −57%, or −80% CT radiation dose respectively, when assigned to group 1, 2, 3, or 4 respectively. FD acquisitions were reconstructed with iterative reconstruction, iDose4. RD acquisitions were additionally reconstructed with iterative model-based reconstruction (IMR) levels 1–3 with different levels of noise suppression. CT numbers, noise and contrast-to-noise ratios were measured in muscle, fat and bladder. Subjective image quality was evaluated on seven aspects including artefacts, osseous structures, prosthetic components and soft tissues.ResultsSeventy-six patients were randomly assigned to one of the four groups. While reducing radiation dose by 20%, 40%, 57%, or 80% in combination with IMR, CT numbers remained constant. Compared with iDose4, the noise decreased (p < 0.001) and contrast-to-noise ratios increased (p < 0.001) with IMR. O-MAR improved CT number accuracy in the bladder and reduced noise in the bladder, muscle and fat (p < 0.01). Subjective image quality was rated lower on RD IMR images than FD iDose4 images on all seven aspects (p < 0.05) and was not related to the applied radiation dose reduction.ConclusionIn RD IMR with O-MAR images, CT numbers remained constant, noise decreased and contrast-to-noise ratios between muscle and fat increased compared with FD iDose4 with O-MAR images in patients with metal-on-metal THAs. Subjective image quality reduced, regardless of the degree of radiation dose reduction.

Immobilization of Live Caenorhabditis elegans Individuals Using an Ultra-thin Polydimethylsiloxane Microfluidic Chip with Water Retention.

Radiation is widely used for biological applications and for ion-beam breeding, and among these methods, microbeam irradiation represents a powerful means of identifying radiosensitive sites in living organisms. This paper describes a series of on-chip immobilization methods developed for the targeted microbeam irradiation of live individuals of Caenorhabditis elegans. Notably, the treatment of the polydimethylsiloxane (PDMS) microfluidic chips that we previously developed to immobilize C. elegans individuals without the need for anesthesia is explained in detail. This chip, referred to as a worm sheet, is resilient to allow the microfluidic channels to be expanded, and the elasticity allows animals to be enveloped gently. Also, owing to the self-adsorption capacity of the PDMS, animals can be sealed in the channels by covering the surface of the worm sheet with a thin cover film, in which animals are not pushed into the channels for enclosure. By turning the cover film over, we can easily collect the animals. Furthermore, the worm sheet shows water retention and allows C. elegans individuals to be subjected to microscopic observation for long periods under live conditions. In addition, the sheet is only 300 µm thick, allowing heavy ions such as carbon ions to pass through the sheet enclosing the animals, thus allowing the ion particles to be detected and the applied radiation dose to be measured accurately. Because selection of the cover films used for enclosing the animals is very important for successful long-term immobilization, we conducted the selection of the suitable cover films and showed a recommended one among some films. As an application example of the chip, we introduced imaging observation of muscular activities of animals enclosing the microfluidic channel of the worm sheet, as well as the microbeam irradiation. These examples indicate that the worm sheets have greatly expanded the possibilities for biological experiments.

Effects of radiation dose levels and spectral iterative reconstruction levels on the accuracy of iodine quantification and virtual monochromatic CT numbers in dual-layer spectral detector CT: an iodine phantom study.

The purpose of this study is to investigate the accuracy of iodine quantification and virtual monochromatic CT numbers obtained with the dual-layer spectral CT (DLCT) using a phantom at different radiation dose levels and spectral iterative reconstruction (IR) levels. An abdomen phantom with seven iodine inserts (2.0, 2.5, 5.0, 7.5, 10.0, 15.0, 20.0 mg/mL) was imaged using a DLCT scanner. Five repeated scans were performed at computed tomography dose index volume (CTDIvol) levels of 5, 10, 15, 20, 25 mGy at tube voltages of 120 and 140 kVp, respectively. Spectral-based images were reconstructed using four spectral IR levels (spectral level of 0, 2, 4, 6). Iodine density images and virtual monochromatic images (VMI) at energy levels of 50, 70 and 120 keV were created. The absolute percentage bias (APB) of the measured iodine concentration and the true iodine concentration, and the measured VMI CT numbers and the theoretical VMI CT numbers were compared to determine the difference of radiation dose levels and different spectral IR levels. At CTDIvol levels of 25, 20, 15, 10 mGy, radiation dose levels had no effect on the accuracy of iodine quantitation; at CTDIvol level of 5 mGy, the accuracy of iodine quantification was the poorest, with the mean APBiodine of 4.33% (P<0.05). There was no significant difference in the accuracy of iodine quantitation between 120 and 140 kVp (P=0.648). At energy levels of 50, 70 and 120 keV, there was no significant difference in the accuracy of the VMI CT numbers among the CTDIvol levels of 25, 20 and 15 mGy. However, the accuracy of VMI CT numbers was significantly degraded at the CTDIvol levels of 10 and 5 mGy (P<0.05). At energy level of 50 keV, the accuracy of VMI CT numbers was not affected by tube voltages (kVps) used (P=0.125). At the energy levels of 70 and 120 keV, 140 kVp produced a smaller bias than 120 kVp, with the mean APBHU at 120 and 140 kVp being of 3.62% vs. 2.99% for 70 keV (P<0.01), and 11.65% vs. 9.28% for 120 keV (P<0.01), respectively. Spectral IR levels did not affect the accuracy of iodine quantification and VMI CT numbers (P=0.998, P=0.963). The accuracy of iodine quantification and VMI CT numbers was only affected by very low radiation dose levels. At the clinically applied radiation dose levels of >10 mGy, the accuracy of both iodine quantification and VMI CT numbers is relatively stable and high.

Повышение биологической ценности белка и увеличение сроков хранения полуфабриката из вешенки обыкновенной методом электронной стерилизации

The question of the biological value of mushroom protein is not limited to the study of its composition. In addition, the associated problem of its digestibility and assimilability is widely discussed in the scientific community, including in the scientific publications discussed in this article. Mycoprotein derived from proteinrich unicellular fungi biomass is commonly used in contemporary food-production processes. In Russia, however, an alternative source of protein consists in the higher fungi including the common oyster mushroom (Pleurotus ostreatus). It is known that fungal proteins having a rich amino acid composition are absorbed at the level of plant proteins, since they are “packed” in the intercellular chitinous membrane. Various technological methods are used in the processing of raw fungi materials in order to destroy the membrane and release the protein macromolecule. These include traditional processing methods, such as grinding, thermal exposure, etc. In the present article, electromagnetic sterilisation of convenience foods is considered as a means of improving product safety. The authors studied the effect of ionising electron radiation on the physicochemical properties of mushroom products using the example of a heat-treated, vacuum-packaged, semi-finished oyster mushroom product. The applied radiation doses were 1, 3, 6 and 9 kGy. The obtained data showed that, when a semifinished product is irradiated with a dose of 1 to 6 kGy, a greater amount of protein is released compared to unirradiated samples; moreover, that the content of a number of essential amino acids also increases. Therefore, this method allows the biological activity of the nutrients to be increased. The sterilising effect of ionising radiation was achieved with a dose of 6 kGy due to slowing the growth of microorganisms: no pathogenic microorganisms were detected and no growth was observed over a period of 21 days. Thus, electronic ionising radiation as part of the technological process of processing mushrooms allows the biological value of the protein to be increased, preventing the growth of microorganisms and thereby extending the shelf life of mushroom products.

Demonstration of femtosecond X-ray pump X-ray probe diffraction on protein crystals.

The development of X-ray free-electron lasers (XFELs) has opened the possibility to investigate the ultrafast dynamics of biomacromolecules using X-ray diffraction. Whereas an increasing number of structures solved by means of serial femtosecond crystallography at XFELs is available, the effect of radiation damage on protein crystals during ultrafast exposures has remained an open question. We used a split-and-delay line based on diffractive X-ray optics at the Linac Coherent Light Source XFEL to investigate the time dependence of X-ray radiation damage to lysozyme crystals. For these tests, crystals were delivered to the X-ray beam using a fixed-target approach. The presented experiments provide probe signals at eight different delay times between 19 and 213 femtoseconds after a single pump event, thereby covering the time-scales relevant for femtosecond serial crystallography. Even though significant impact on the crystals was observed at long time scales after exposure with a single X-ray pulse, the collected diffraction data did not show significant signal reduction that could be assigned to beam damage on the crystals in the sampled time window and resolution range. This observation is in agreement with estimations of the applied radiation dose, which in our experiment was clearly below the values expected to cause damage on the femtosecond time scale. The experiments presented here demonstrate the feasibility of time-resolved pump-multiprobe X-ray diffraction experiments on protein crystals.

Development of ultra-thin chips for immobilization of Caenorhabditis elegans in microfluidic channels during irradiation and selection of buffer solution to prevent dehydration

BackgroundTargeted microbeam irradiation of Caenorhabditis elegans allows the effective knockdown of specific regions, thus helping to identify their roles in processes such as locomotion. We previously employed on-chip immobilization of individuals without anesthesia; however, this method was limited by the thickness of the chip, which prevented the detection of ions passing through the animal, and by dehydration of the animals after prolonged immobilization. New MethodWe developed ultra-thin, ion-penetrable, polydimethylsiloxane microfluidic chips, referred to as Worm Sheets, with and without wettability (hydrophilicity/hydrophobicity), and identified suitable buffer conditions for maintaining moisture in the microfluidic channels. ResultsUsing a collimating microbeam system, we demonstrated that carbon ions (with a range of ∼1 mm) could pass through the chip, thus allowing the ions to be detected and the applied radiation dose to therefore by measured accurately. We also examined the locomotion of C. elegans following on-chip immobilization in different buffers. Locomotion was decreased in certain buffers on unwettable chips as a result of dehydration due to evaporation, but not on wettable chips. However, locomotion was unaffected on either chip in the presence of a gelatin-based wash buffer. Comparison with Existing Method(s)We developed 300-μm-ultra-thin, wettable, ion-penetrable chips for immobilizing C. elegans and provided initial guidance regarding suitable buffer solutions to maintain moisture in microfluidic channels. ConclusionsThis improved, wettable chip, together with the identification of suitable buffer conditions, will become a powerful tool for prolonged immobilizing C. elegans, and is widely applicable not only to microbeam irradiation but also to neurobiological assays.

Wholesomeness and safety of meat of laying hens fed irradiated aflatoxin B1-contaminated diet

THE AIM of this study is to evaluate the effect of gamma (γ) radiations on the safety of processed diets to eliminate the negative effects of aflatoxin-B1 (AFB1) on the health of consumers. One hundred fifty adult female Westar rats were used. The rats were divided into 5 experimental groups (G). G1; rats served as a control which were fed a meal of flesh (breast and thigh muscles) and organs (liver, kidney, spleen and heart) of laying hens that fed before slaughtering diet non-contaminated with AFB1. G2; the rats were fed flesh of laying hens fed before slaughtering contaminated diet with 0.2mg AFB1kg−1, G3, G4 and G5 rats were fed flesh and organs of slaughtered laying hens fed before being slaughtered contaminated diet with 0.2mg AFB1 and treated with γ-irradiation at 10, 20 and 30kGy, respectively. The feeding continued for 3 weeks (experimental duration), then followed by another 3 weeks period on commercial non-contaminated ration (recovery duration). The obtained results showed that the feed intake, live body weight, blood total protein, albumin, and globulin were significantly decreased (P≤0.05) in rats of G2 during the experimental duration compared to G1. However, an improvement was observed in all parameters for rats of G3, G4 and G5. This improvement was parallel with increasing the dose levels of γ-ray (at 10, 20 and 30kGy), respectively. On the other hand, G2 showed an increase in the relative organ weights and AFB1 residues in breast tissues and organs including (liver, kidneys, spleen and heart), creatinine, liver function including aspertate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP). The experimental regimes for rats of G3, G4 and G5 were effective at reducing the deleterious effect of AFB1 on residues in breast tissues and organs. They normalized the relative organ weights as a function of radiation doses. Moreover, an improvement in serum liver enzymes, thyroid hormones and sexual hormones occurred, which reflects their effects on metabolism and reproductive efficiency of rats and this improvement was proportional with increasing the radiation doses up to 30kGy. It could be concluded that the radiation processing (at the applied radiation doses) of contaminated diet with AFB1 has significantly improved all parameters (P<0.05) which were negatively affected by AFs. Also, improvements were noticed in G3 and G4. A greater amelioration was obtained for group G5 followed a recovery phase.

Nowoczesna tomografia komputerowa w diagnostyce wybranych wad wrodzonych żył płucnych

An excellent spatial and temporal resolution of computed tomography (CT) provides for precise evaluation of congenital cardiac malformation in selected group of patients. CT allows for quick, simultaneous assessment of all chest structures, such as pulmonary vessels, lung parenchyma and bones. Recent advances in CT hardware and software result in fast scanning of large anatomic ranges with a single lamp rotation without the need for patient's sedation and breath hold. The only limitation of CT is nowadays the exposure to ionizing radiation but with the new generation of scanners equipped with iterative reconstruction it is possible to reduce applied radiation dose while maintaining image quality. CT evaluation of pulmonary venous anomalies is well described, accurate for determining the site of anatomic obstruction in anomalous pulmonary venous return and has been shown to be highly specific when compared to operative findings. This article presents short review on current possibilities of CT diagnostic management of selected congenital pulmonary venous malformations.

Some effects of radiation treatment of biodegradable PCL/PLA blends

Abstract Changes in melt flow rate (MFR), mechanical properties, and morphology occurring upon the electron beam (EB) irradiation of polycaprolactone/polylactide (PCL/PLA) blends were discussed. Reference samples and examined blends were prepared using co-rotating twin screw extruder. The obtained materials were irradiated with high-energy EB. The applied radiation dose was 40 kGy. Studies have shown that EB irradiation affected the properties of PCL/PLA blends in different ways. In the case of pure PLA and blends with a significant content of PLA the degradation process mainly occurred, whereas in pure PCL and blends with a significant content of PCL the degradation process was almost absent. Moreover, it was found that properties of PCL/PLA blends depended mainly on the content of PLA phase that was more susceptible to electron radiation than the PCL one.