Comet Images Research Articles

Using Stereoscopic Observations of Cometary Plasma Tails to Infer Solar Wind Speed

Abstract Detection of the solar wind speed near the Sun is significant in understanding the heating and acceleration of the solar wind. Cometary plasma tails have long been used as natural probes for solar wind speed; previous solar wind speed estimates via plasma tails, however, were based on comet images from a single viewpoint, and the projection effect may influence the result. Using stereoscopic observations from the Solar Terrestrial Relations Observatory and the Solar and Heliospheric Observatory, we three-dimensionally reconstruct the plasma tails of three comets C/2012 S1 (ISON), C/2010 E6, and C/2011 W3 (Lovejoy) and infer the ambient solar wind speed. The first comet is located between 3.5 and 6 solar radii (Rs) away from the Sun at high latitudes; the estimated solar wind speed is about 300–500 km s−1. The second comet is located within 10 Rs and about 20° away from the ecliptic; the estimated solar wind speed is about 200–320 km s−1. The third comet is also located at low latitudes but farther (>20 Rs) away from the Sun; the estimated solar wind speed is about 100–600 km s−1. For comets near the ecliptic, our results are close to those predicted by MHD models, whereas for the comet at high latitudes, the deviation between our estimate and the model results is notable. This consistency and difference could be used to constrain and improve solar wind models. We will seek opportunities to apply the method to comet 322P, whose tail may sweep the Parker Solar Probe.

Mt. Wendelstein imaging of comet 41P/Tuttle-Giacobini-Kresak during the 2017 perihelion arc

Context.In April 2017 comet 41P/Tuttle-Giacobini-Kresak (41P) passed perihelion close to Earth.Aims.We present observations of the comet and aim to use these to characterize its dust environment in the coma and of physical properties of the nucleus.Methods.41P was imaged in the visible at the Mt. Wendelstein observatory over 45 nights between 2017 March 11 and 2017 July 17. Photometry of the coma provides information on the dust activity of the comet. Nucleus dimensions are determined by comparing radial profiles of observed images with those from models of the brightness distribution in the near-nucleus coma. Coma and tail structures in the images are enhanced using adaptive Laplace filtering and image normalization techniques. The geometry of the coma structures found are compared to results from dust models of the comet in order to obtain information on the nucleus rotation axis and the location of active regions on the nucleus.Results.Analyzing the evolution of the dust activity of the comet versus solar distance gives different results depending on the assumed phase angle corrections for the dust. Contamination from light emissions of the coma gas modified the colors in the coma and the slopes of the radial profiles. The light distribution in the very inner coma indicates some dust fragmentation close to the nucleus. The appearance of a prominent coma fan during the time period from March to May 2017 constrains the rotation axis of the nucleus (52 deg obliquity, 50 deg rotation angle of the perihelion meridian). This fan is produced by an extended region beyond about 50 deg latitude on the nucleus. Two narrow regions at low northern to equatorial latitudes were responsible for the time-variable occurrence of linear dust jets in the coma. An outburst of about 0.6 mag on 2017 May 11 generated various dust structures in the coma. The outburst originated from a region extending over a latitude range from +30 deg to −5 deg and released about 3000 tons of dust into the coma. The brightness of the nucleus indicates an equivalent radius of about 600 m and a minimum axis ratio larger than two.

Classification of DNA damages on segmented comet assay images using convolutional neural network

Background and ObjectiveIdentification and quantification of DNA damage is a very significant subject in biomedical research area which still needs more robust and effective methods. One of the cheapest, easy to use and most successful method for DNA damage analyses is comet assay. In this study, performance of Convolutional Neural Network was examined on quantification of DNA damage using comet assay images and was compared to other methods in the literature. Methods796 single comet grayscale images with 170 x 170 resolution labeled by an expert and classified into 4 classes each having approximately 200 samples as G0 (healthy), G1 (poorly defective), G2 (defective) and G3 (very defective) were utilized. 120 samples were used as test dataset and the rest were used in data augmentation process to achieve better performance with training of Convolutional Neural Network. The augmented data having a total of 9995 images belonging to four classes were used as network training data set. ResultsThe proposed model, which was not dependent to pre-processing parameters of image processing for DNA damage classification, was able to classify comet images into 4 classes with an overall accuracy rate of 96.1%. ConclusionsThis paper primarily focuses on features and usage of Convolutional Neural Network as a novel method to classify comet objects on segmented comet assay images.

THE RE-PROCESSING RESULTS OF PHOTOGRAPHIC OBSERVATIONS OF ASTEROIDS WITH GAIA CATALOG AT THE MAO NAS OF UKRAINE

In total, about 4,500 asteroid po-sitions were determined from photographic observations conducted at the MAO NAS of Ukraine in 1952-1996. These are the early positions of the selected minor planets, mostly bright, the observations of which were initiated by the founders of the ORBITA observational program and were made in 1952-1986. The second later positions of asteroids obtained from digitized plates from photographic observations of the Northern Sky Survey project in 1981-1996. Using digital plate processing technologies, 2292 asteroid positions were obtained, the images of which were fixed during observations and identified during processing.The new star catalog Gaia DR2 was used to study changes in determining the accuracy of equatorial coordinates for various faint objects on plates. For several 8 plates with images of Pluto comets and faint asteroids of particular interest due to the lack of observations in the past, new complete processing of scans of these plates was performed. The Gaia DR2 was used as a reference catalog. The asteroid positions from early observations of 1952- 1986 were determined in accordance with classical linear reduction algorithms. These are 1651 positions of minor planets determined in the PPM catalog system and obtained from observations with the Double Wide-Angle Astrograph. The remaining 591 positions were determined in the systems of old reference catalogs of stars Yale, SAO, AGK3, and obtained from observations with the Double Long-Focus Astrograph. It was for these positions that the calibration with the Gaia catalog was performed. The data on the positions of minor planets digitized from publications and additional data on their reference systems deposited in previous years at VINITI (now VINITI Database RAS) were used. Comparison with JPL ephemeris was performed both for new determinations of asteroid coordinates with the Gaia catalog, and for past determinations obtained in systems of other reference catalogs.

Analysis of the morphological structures of comet 1P/Halley in the perihelion passages in 1910 and 1986

AbstractThis work is based on a systematic analysis of images of comet 1P/Halley collected during its penultimate and ultimate approaches, i.e., in 1910 and 1986. This research has identified, characterized, classified, and compared tail structures of comet 1P/Halley, namely disconnection events (DEs), wavy structures, and solitons. The images of the comet during its 1910 passage, as illustrated in the Atlas of Comet Halley 1910 II (Donn et al. 1986), were compared with those of its approach in 1986 as illustrated in The International Halley Watch Atlas of Large‐Scale Phenomena (Brandt et al. 1992). Two onsets of DEs were discovered after the perihelion passage in 1910 with an average value of the corrected cometocentric velocity (Vc) of 57 ± 15 km s−1. Ten onsets of DEs were discovered after the perihelion passage in 1986 with an average Vc equal to 130 ± 37 km s−1. The mean value of the corrected wavelength λc of wavy structures in 1910 is equal to 1.7 ± 0.1 × 106 km, as compared to 2.2 ± 0.2 × 106 km in 1986. The mean value of the amplitude A of the wave in 1910 is equal to 1.4 ± 0.1 × 105 km and 2.8 ± 0.5 × 105 km in 1986. The goals of this research were to report the results obtained from the analysis of the P/Halley's images from 1910 and 1986, to provide empirical data for comparison, and to form the input for future physical/theoretical work.

Lymphocytes DNA damages and exposure to chlorpyrifos, deltamethrin, penconazole, copper oxicloride

Purpose: The evaluation of the association between different exposure to pesticides and different types of comet images among a group of 26 recruited subject.Material and methods: We have recruited 26 subjects (farmers and not farmers). They were submitted to a blood drawing of 10 mL and a questionnaire was administered to investigate personal habits and work history. By means of the comet assay it was assessed the oxidative DNA damage of peripheral lymphocytes by pesticides in the exposed and non-exposed workers.Result: The data measured by means of the comet were log transformed and the associations (odds ratios – ORs) with the single pesticides were calculated. The regression analysis shows a significant dose effects relationships between the Intensity Score of pesticides exposures tail moment (TM) and other measured parameters. Insecticides TM OR = 17.00 [1.47 – 196.41]. This relationship is independent from the smoking habits.Conclusions: TM values higher than the 75° percentile were significantly associated with the exposure to particular insecticides such as chlorpyriphos, deltamethrin and with other pesticides (near the statistical significance).

Monitoring of the activity and composition of comets 41P/Tuttle–Giacobini–Kresak and 45P/Honda–Mrkos–Pajdusakova

We report on photometry and imaging of the Jupiter family comets 41P/Tuttle–Giacobini–Kresak and 45P/Honda–Mrkos–Pajdusakova with the TRAPPIST-North (TRAnsiting Planets and PlanetesImals Small Telescope) telescope. We observed 41P on 34 nights from February 16 to July 27, 2017, pre- and post-perihelion (rh= 1.04 au), and collected data for comet 45P after perihelion (rh= 0.53 au) from February 10 to March 30, 2017. We computed the production rates of the daughter species OH, NH, CN, C3and C2and we measured the dust proxy, Afρ, for both comets. The peak of water-production rate of 41P was (3.46 ± 0.20) × 1027molecules s−1on April 3, 2017, when the comet was at 1.05 au from the Sun. We have shown that the activity of 41P is decreasing by about 30–40% from one apparition to the next. We measured a mean water-production rate for 45P of (1.43 ± 0.62) × 1027molecules s−1during a month after perihelion. Our results show that these Jupiter family comets had low gas and dust activity and no outburst was detected. Relative abundances, expressed as ratios of production rates and the Afρparameter with respect to OH and to CN, were compared to those measured in other comets. We found that 41P and 45P have a typical composition in terms of carbon-bearing species. The study of coma features exhibited by the CN gas species allowed the measurement of the rotation period of 41P, showing a surprisingly large increase of the rotation period from (30 ± 5) h at the end of March to (50 ± 10) h at the end of April, 2017, in agreement with recent observations by other teams.

Lineaments on the Surface of the Consolidated Material of the Comet 67P/Churyumov−Gerasimenko Nucleus

Morphologic analysis of the fragments (500 × 500 pixels) of images of comet 67P/Churyumov− Gerasimenko obtained with the OSIRIS camera for 18 regions, where the consolidated material is exposed on the surface, has been carried out. In terms of resolution, the images form a series from 0.04 to 1.29 m/pixel; consequently, the areas covered by these fragments vary from 400 to ~400000 m2. In all of the regions, lineaments resembling tension fractures—several dozens of structures per region—are seen; and their number scarcely changes when passing from high-resolution images to lower-resolution ones. It is clear that relatively small lineaments cease to be reliably distinguished when the image resolution worsens, but the largest and well-defined ones remain observable, while the number of larger lineaments grows proportionally to the survey area increasing. Undoubtedly, this is an observational effect, which was demonstrated by examples with an artificially worsened resolution. However, on the other hand, this means that the tension fractures of the consolidated nucleus material represent a hierarchic population of smaller (meters long) to larger (decameters and longer) features. The lineaments seen in the analyzed fragments of images were counted, their lengths were measured, and the spacings (the mean distances between lineaments) and, from them, the depths of penetration of fractures into the nucleus material were estimated. It has been shown that the mean length of lineaments within each studied region depends on its area (which here correlates with the image resolution) and the depths of fracture penetration into the nucleus body depends on the mean length of lineaments. Both dependences are close to a power law. In the images of four regions covering the areas from 100000 to 400000 m2 with a resolution of 0.66−1.29 m/pixel, the structures that look like layering or sheet jointing are seen in addition to fracture lineaments. The tension fractures are apparently formed due to seasonal and diurnal variations of the temperature, while the nature of the formation of the layer-like structures is not yet fully understood.

274 - Protective effects of novel derivatives of vitamin D3 and lumisterol against UVB-induced damage in human keratinocytes involve activation of Nrf2 and P53 defense mechanisms

Objective Ultraviolet B (UVB) plays an important role in the photo-damage of skin through formation of cyclobutane pyrimidine dimers (CPD), the primary mutagenic DNA photoproducts, and regulation of the p53 protective responses against genotoxic damage. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor regulating antioxidant genes, also has a protective role against photo-oxidative damage of the skin. Since the protective role of the active form of vitamin D (1,25(OH)2D3) against UVB induced damage is recognized, we tested whether novel CYP11A1-derived D3-hydroxyderivatives and lumisterol including its hydroxy-derivatives can protect against UVB-induced damage in human keratinocytes. Materials and Methods 1,25(OH)2D3, biochemically generated 20(OH)D3, 1,20(OH)2D3, 20,23(OH)2D3, and 1,20,23(OH)3D3, synthetic lumisterol and its hydroxy-derivatives generated by the action of CYP11A1 including 20(OH)L3, 22(OH)L3, 20,22(OH)2L3, and 24(OH)L3), were used for testing. Cells were treated with compounds for 24 h pre-and post-UVB irradiation at doses of 25, 50, 75, and 200 mJ/cm2. Oxidant formation was determined by the DCFA-DA method. DNA damage was assessed using the comet assay. Nuclear expressions of CPD, phospho-p53 and Nrf2 were assayed by immunofluorescence and western blotting, respectively. Results Trea tment with compounds at concentrations 10-9, 10-8, and 10-7 M showed a dose-dependent reduction of oxidant formation in comparison to non-treated cells. Compounds (10-7 M) were also able to protect against DNA damage and/or induce DNA repair for cells irradiated with UVB (50 mJ/cm2) by reducing CPD levels and the tail moment of comet images. They stimulated p53 phosphorylation at Ser-15 and increased its concentration in the nucleus, and enhanced Nrf2 translocation to the nucleus. Conclusion 1,25(OH)2D3, CYP11A1-derived D3-hydroxyderivatives as well as lumisterol and its hydroxy-derivatives protect keratinocytes against UVB-induced damage via activation of DNA damage protective pathways that include Nrf2 activation and p53-phosphorylation. These compounds represent promising anti-photodamaging agents.

On deviations from free-radial outflow in the inner coma of comet 67P/Churyumov–Gerasimenko

The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard the European Space Agency's Rosetta spacecraft acquired images of comet 67P/Churyumov–Gerasimenko (67P) and its surrounding dust coma starting from May 2014 until September 2016. In this paper we present methods and results from analysis of OSIRIS images regarding the dust outflow in the innermost coma of 67P. The aim is to determine the global dust outflow behaviour and place constraints on physical processes affecting particles in the inner coma. We study the coma region right above the nucleus surface, spanning from the nucleus centre out to a distance of about 50 km comet centric distance (approximately 25 average comet radii). We primarily adopt an approach used by Thomas and Keller (1990) to study the dust outflow. We present the effects on azimuthally-averaged values of the dust reflectance of non-radial flow and non-point-source geometry, acceleration of dust particles, sublimation of icy dust particles after ejection from the surface, dust particle fragmentation, optical depth effects and the influence of gravitationally bound particles. All of these physical processes could modify the observed distribution of light scattered by the dust coma.In the image analysis, profiles of azimuthally averaged dust brightness as a function of impact parameter b (azimuthal average, “Ā-curve”) were fitted with a simple function that best fits the shape of our profile curves (f(b;u,v,w,z)=u/bv+wb+z). The analytical fit parameters (u, v, w, z), which hold the key information about the dust outflow behaviour, were saved in a comprehensive database.Through statistical analysis of these information, we show that the spatial distribution of dust follows free-radial outflow behaviour (i.e. force-free radial outflow with constant velocity) beyond distances larger than ∼11.9 km from the comet centre, which corresponds to a relative distance of about 6 average comet radii from the comet centre. Hence, we conclude that beyond this distance, and on average, fragmentation and gravitationally bound particles are negligible processes in determining the optically scattered light distribution in the innermost coma. Closer to the nucleus we observe dust outflow behaviour that deviates from free-radial outflow.A comparison of our result profiles with numerical models using a Direct Simulation Monte Carlo (DSMC) approach with dust particle distributions calculated using a test particle approach has been used to demonstrate the influence of a complex shape and particle acceleration on the azimuthal average profiles. We demonstrate that, while other effects such as fragmentation or sublimation of dust particles cannot be ruled out, acceleration of the dust particles and effects arising from the shape of the irregular nucleus (non-point source geometry) are sufficient to explain the observed dust outflow behaviour from image data analysis.As a by-product of this work, we have calculated “Afρ” values for the 1/r regime. We found a peak in the coma activity in terms of Afρ (normalised to a phase angle of 90°) of ∼210 cm 20 days after perihelion. Furthermore, based on simplified models of particle motion within bound orbits, it is shown that limits on the total cross-sectional area of bound particles might be derived through further analysis. An example is given.

Strong CO+ and Emission in Comet C/2016 R2 (Pan-STARRS)*

Abstract We report on imaging and spectroscopic observations of comet C/2016 R2 (Pan-STARRS) obtained with the 0.8 m and 2.7 m telescopes of McDonald Observatory in 2017 November and December, respectively. The comet was at a heliocentric distance greater than 3 au during both sets of observations. The images showed a well-developed tail with properties that suggested it was an ion tail. The spectra confirmed that we were observing well-developed bands of CO+ and . The detection was unequivocally cometary and was one of the strongest bands of detected in a comet spectrum. We derived the ratio of these two ions and from that we were able to derive that N2/CO = 0.15. This is the highest such ratio reported for a comet.

The global meter-level shape model of comet 67P/Churyumov-Gerasimenko

We performed a stereo-photogrammetric (SPG) analysis of more than 1500 Rosetta/OSIRIS NAC images of comet 67P/Churyumov-Gerasimenko (67P). The images with pixel scales in the range 0.2−3.0 m/pixel were acquired between August 2014 and February 2016. We finally derived a global high-resolution 3D description of 67P’s surface, the SPG SHAP7 shape model. It consists of about 44 million facets (1−1.5 m horizontal sampling) and a typical vertical accuracy at the decimeter scale. Although some images were taken after perihelion, the SPG SHAP7 shape model can be considered a pre-periheliondescription and replaces the previous SPG SHAP4S shape model. From the new shape model, some measures for 67P with very low 3σ uncertainties can be retrieved: 18.56 km3 ± 0.02 km3 for the volume and 537.8 kg/m3 ± 0.7 kg/m3 for the mean density assuming a mass value of 9.982 × 1012 kg.

The Rotation and Other Properties of Comet 49P/Arend–Rigaux, 1984–2012

Abstract We analyzed images of comet 49P/Arend–Rigaux on 33 nights between 2012 January and May and obtained R-band lightcurves of the nucleus. Through usual phasing of the data, we found a double-peaked lightcurve having a synodic rotation period of 13.450 ± 0.005 hr. Similarly, phase dispersion minimization and the Lomb–Scargle method both revealed rotation periods of 13.452 hr. Throughout the 2011/2012 apparition, the rotation period was found to increase by a small amount, consistent with a retrograde rotation of the nucleus. We also reanalyzed the publicly available data from the 1984/1985 apparition by applying the same techniques, finding a rotation period of 13.45 ± 0.01 hr. Based on these findings, we show that the change in rotation period is less than 14 s per apparition. Furthermore, the amplitudes of the lightcurves from the two apparitions are comparable, to within reasonable errors, even though the viewing geometries differ, implying that we are seeing the comet at a similar sub-Earth latitude. We detected the presence of a short-term jet-like feature in 2012 March, which appears to have been created by a short-duration burst of activity on March 15. Production rates obtained in 2004/2005, along with reanalysis of the previous results from 1984/1985, imply a strong seasonal effect and a very steep fall-off after perihelion. This, in turn, implies that a single source region, rather than leakage from the entire nucleus, dominates activity.

Maternal prenatal stress predicts altered HPA axis reactivity in presence of rhinovirus among 10-week-old infants

In recent years, development of software programs in medicine field has proceeded in a rapid manner. Comet assay is one of the research methods in medicine field that displays whether DNA has damage. In this study, it is aimed to share experience of dynamic time warping method and decision tree to decide whether DNA has damage and grade DNA damage by means of the software program.The application analyzes manually extracted RGB single comet images whose centers are manually marked. The application performs pixel profile analysis at the directions of vertical and horizontal based on the center of comet. The bidirectional pixel profile results are used as inputs of dynamic time warping. Four novel and one conventional measurement parameters some of which are calculated by dynamic time warping are given to decision tree.The decision tree identifies whether DNA has damage and grades DNA damage categorizing four damage levels with accuracy of 99.03% using only two of five measurement parameters.This paper mainly focuses on features and usage of dynamic time warping and decision tree as a novel method to identify and grade DNA damage on comet images.

A novel method to identify and grade DNA damage on comet images

Background and objectiveIn recent years, development of software programs in medicine field has proceeded in a rapid manner. Comet assay is one of the research methods in medicine field that displays whether DNA has damage. In this study, it is aimed to share experience of dynamic time warping method and decision tree to decide whether DNA has damage and grade DNA damage by means of the software program. MethodsThe application analyzes manually extracted RGB single comet images whose centers are manually marked. The application performs pixel profile analysis at the directions of vertical and horizontal based on the center of comet. The bidirectional pixel profile results are used as inputs of dynamic time warping. Four novel and one conventional measurement parameters some of which are calculated by dynamic time warping are given to decision tree. ResultsThe decision tree identifies whether DNA has damage and grades DNA damage categorizing four damage levels with accuracy of 99.03% using only two of five measurement parameters. ConclusionsThis paper mainly focuses on features and usage of dynamic time warping and decision tree as a novel method to identify and grade DNA damage on comet images.

Determinación mediante prueba cometa del daño genético causado por uso de ivermectina en vacas cebú (Bos taurus indicus)

Objetivo. El objetivo del trabajo fue evaluar el daño genético causado por el uso de Ivermectina (IVM) en vacas cebú (Bos taurus indicus). Materiales y Métodos. Se tomaron quince vacas, con edad entre tres y cuatro años, peso promedio de 350 kilogramos, condición corporal entre 3 y 3,5. Se utilizaron tres grupos experimentales con cinco animales por grupo, los cuales se expusieron a la concentración de IVM al 1% y 3,15% más un grupo control (sin aplicación de IVM). La muestra sanguínea por animal fue realizada mediante punción venosa yugular o caudal medial con aguja para vacutainer ®, extrayéndose 8 ml de sangre. Las muestras sanguíneas fueron recolectadas a los 9, 18 y 27 días postratamiento. Resultados. La visualización de los cometas se realizaron con microscopio de fluorescencia, las células fueron evaluadas por medio de registro visual y por el software Comet Imagen. Se evidenció la presencia de núcleos con migración de ADN en todas las placas analizadas. Los valores de clasificación de los cometas, denotaron células con altos niveles de daño alto (grado 3). El índice de daño del ADN de los tratamientos al 1% y 3,15% fue significativo, al relacionarlo con el grupo control. Conclusión. Los resultados de este estudio evidenciaron el probable potencial genotóxico del uso de la IVM en ganado vacuno.

SEARCH SMALL BODIES IMAGES IN COLLECTIONS DIGITIZED PHOTOGRAPHIC OBSERVATIONS OF PREVIOUS YEARS

Photographic observations of XX century is an important source of information on small bodies of the Solar system. The observations of chronologically earlier oppositions, photometric evaluation of brightness for long periods of time allow refining the orbits of asteroids and identifying various non-stationaries. Unfortunately international databases were contained a very little observable data for accurate estimates of geometric and kinematic parameters of asteroids. We analyzed the results of digital processing of 338 photographic plates of Northern Sky Survey (FON) project. Modern approach to processing early observations using new digital technologies provides a sufficiently high accuracy of coordinates and magnitudes for all objects on astroplates. As a result 570 images of asteroids and 4 images of comets from 8-16 magnitudes were detected on these plates. Equatorial coordinates and stellar magnitudes of them were composed to catalog of asteroids. All positions were compared with ephemeris. Analysis of ephemeris calculations with known today about the several hundred small planets with observation data showed some interesting results.

Digital Image Techniques for the Comet-FISH Assay in the Search for DNA Damage and Repair

Studies worldwide have demonstrated that the Comet-FISH assay can detect DNA damage and repair in a number of genes, gene regions and loci. Any gene could be detected if a suitable probe is available in theory. Assay’s relative speed and sensitivity make it a very handy laboratory technique for studying the cellular response to damage. It has also the advantage of being able to study specific genes and gene regions of interest, particularly those associated with disease. Its speed and sensitivity also makes it versatile for use in a clinical setting whereby data can be quickly supplied from patient cell samples. The test helps to get information about the development of treatment. This is proved to be particularly beneficial in cancer management, where increasing emphasis is being placed on personalized medicine. Until recently, no research group has yet reported the successful use of a reliable software package for accurately counting hybridization signals from comet slides. They prefer counting signals manually. Manual work is both time consuming and laborious, and also brings in user subjectivity. This study is an attempt in computerization of the process. In a case study, the comet image is processed by the help of digital image handling techniques, and parameters that will help to decide about the DNA damage are derived.

Assessment of status of three water bodies in Serbia based on tissue metal and metalloid concentration (ICP-OES) and genotoxicity (comet assay)

Metals and metalloids are natural components of the biosphere, which are not produced per se by human beings, but whose form and distribution can be affected by human activities. Like all substances, they are a contaminant if present in excess compared to background levels and/or in a form that would not normally occur in the environment. Samples of liver, gills, gonads and muscle from European chub, Squalius cephalus, were analyzed for Al, As, B, Ba, Cr, Cu, Fe, Hg, Mn, Mo, Sr and Zn using inductively coupled plasma optical emission spectrometry (ICP-OES) to highlight the importance of tissue selection in monitoring research. The comet assay or single cell gel electrophoresis (SCGE) was selected as an in vivo genotoxicity assay, a rapid and sensitive method for measuring genotoxic effects in blood, liver and gills of the European chub. Microscopic images of comets were scored using Comet IV Computer Software (Perceptive Instruments, UK).The objective of our study was to investigate two reservoirs, Zlatar and Garasi, and one river, Pestan by: (i) determining and comparing metal and metalloid concentrations in sediment, water and tissues of European chub: liver, gills, muscle and gonads (ii) comparing these findings with genotoxicity of water expressed through DNA damage of fish tissues.A clear link between the level of metals in water, sediment and tissues and between metal and genotoxicity levels at examined sites was not found. This suggests that other xenobiotics (possibly the organic compounds), contribute to DNA damage.

Prognostic value of residual pulmonary congestion at discharge assessed by lung ultrasound imaging in heart failure.

Residual pulmonary congestion at discharge is associated with poor prognosis in heart failure (HF), but its quantification through physical examination is challenging. Ultrasound imaging of lung comets (B-lines) could improve congestion evaluation. The aim of this study was to assess the short-term prognostic value of B-lines after discharge from HF hospitalisation compared with other indices of haemodynamic congestion (BNP, E/e', and inferior vena cava diameter) or clinical status (NYHA class). Sixty consecutive HF inpatients underwent clinical examination, echocardiography, and lung ultrasound at discharge, independently of, and in addition to routine management by the attending physicians. The median B-line count was 8.5 (5-34). Three-month event-free survival for the primary endpoint (all-cause death or HF hospitalisation) was 27 ± 10% in patients with ≥30 B-lines and 88 ± 5% in those with <30 B-lines (P < 0.0001). In a multivariable model, ≥30 B-lines significantly predicted the combined endpoint (hazard ratio 5.66, 95% confidence interval 1.74-18.39, P = 0.04), along with NYHA ≥III and inferior vena cava diameter, while other indirect measures of congestion (BNP and E/e' ≥15) were not retained in the model; furthermore ≥30 B-lines independently also predicted the secondary outcomes (HF hospitalisation and death). Importantly, B-line addition to NYHA class and BNP was associated with improved risk classification (integrated discrimination improvement 15%, P = 0.02; continuous net reclassification improvement 65%, P = 0.03). Residual pulmonary congestion at discharge, as assessed by a B-line count ≥30, is a strong predictor of outcome. Lung ultrasonography may represent a useful tool to identify and monitor congestion and optimize therapy during and/or after hospitalisation for HF, which should be further validated in multicentre studies.