934 research outputs found
VUV-Vis optical characterization of Tetraphenyl-butadiene films on glass and specular reflector substrates from room to liquid Argon temperature
The use of efficient wavelength-shifters from the vacuum-ultraviolet to the
photosensor's range of sensitivity is a key feature in detectors for Dark
Matter search and neutrino physics based on liquid argon scintillation
detection. Thin film of Tetraphenyl-butadiene (TPB) deposited onto the surface
delimiting the active volume of the detector and/or onto the photosensor
optical window is the most common solution in current and planned experiments.
Detector design and response can be evaluated and correctly simulated only when
the properties of the optical system in use (TPB film + substrate) are fully
understood. Characterization of the optical system requires specific, sometimes
sophisticated optical methodologies. In this paper the main features of TPB
coatings on different, commonly used substrates is reported, as a result of two
independent campaigns of measurements at the specialized optical metrology labs
of ENEA and University of Tor Vergata. Measured features include TPB emission
spectra with lineshape and relative intensity variation recorded as a function
of the film thickness and for the first time down to LAr temperature, as well
as optical reflectance and transmittance spectra of the TPB coated substrates
in the wavelength range of the TPB emission
ELECTROPHORETICALLY HOMOGENEOUS ANTIBODY SYNTHESIZED BY SPLEEN FOCI OF IRRADIATED REPOPULATED MICE
106 splenocytes from primed donors were injected, together with sheep erythrocytes (SRBC), into X-irradiated syngeneic mice. 8 days later the spleens were excised and cut into small fragments, keeping track of their location in the organ. Each fragment was cultured individually for 24 hr in the presence of 14C amino acids and the culture fluids were assayed for antibody activity. The antibody-producing fragments were found to be clustered in few restricted areas (foci) surrounded by negative tissue. The anti-SRBC antibody from single foci was purified by absorption on stroma followed by acid elution. Thereafter, it was subjected to electrophoresis and immunoelectrophoresis. The radioautography of the runs showed a considerable degree of homogeneity. Distinct and sharp spikes were localized in the beta and gamma region. The pattern of each focus is unique from the point of view of the number of spikes and their mobility. Eluates obtained from many pooled fragments gave a broad radioactive smear in beta-gamma region. Many foci synthesized antibody migrating as a single band. This homogeneous protein is probably the product of a clone of cells homogeneously differentiated. However, some foci producing two and probably more antibody bands were also encountered. Two interpretations of the finding can be given. Either more than one precursor may participate in the formation of a focus or a differentiation switch may occur during the clonal expansion
Case of Anorchia in a Mixed-Breed Dog
Anorchia is a rare and often poorly understood disorder of sexual development. In the present case report, we
used a multidisciplinary approach to diagnose a case of anorchia in a 30-month old dog. The diagnostic process
began with gathering the dog medical history followed by a clinical visit with the patient, which
included a general wellness examination as well as an examination of the genital system. As suggested in the
relevant literature, the dog underwent an ultrasound and then computed tomography (CT) of the genital system,
which confirmed the diagnosis of testicular agenesis. Genetic testing confirmed the male XY karyotype.
Hormone testing also supported the diagnosis: testosterone and anti-M€ullerian hormone levels were below
their reference ranges, and luteinizing hormone (LH) was above 1 ng/mL. Following the diagnostic procedures
suggested in the relevant literature, the present study confirms anorchia in the dog and describes a
case of testicular agenesis in the canine species
The Role of Spatial Exploration and Territoriality in Establishing Gilthead Seabream (Sparus aurata) Hierarchies, and Their Effects upon Underlying Stress Physiology
Territoriality, spatial exploration and social hierarchy are strictly related behaviors in gregarious fishes, and are often under-appreciated in farms where the individuals are confined within crowded spaces. In this study, we investigated the role of spatial exploration, elucidating the importance of time upon forming the social organization, and the role of the territoriality in gilthead seabream (Sparus aurata), using two experimental approaches. In the first approach, three fish were placed sequentially in the aquarium with an interval of two days (sequential model), while in the second (simultaneous model), two fish were simultaneously placed in an aquarium divided by a barrier which was removed after a certain period of time. To study the effect of social stress and spatial perception in the two models, we monitored behavior (aggressive acts and feeding priority), integrated with the evaluation of physiological and cellular stress parameters, such as phagocytosis, cortisol, glucose, and blood osmolarity levels. After the establishment of the social hierarchy in the "sequential model", we observed that the levels of cortisol and an immunological cell-mediated marker were higher in subordinate individuals than in the dominant ones. We observed a different modulation of phagocytic activity in peritoneal cavity cells between dominant and subordinates, demonstrating that social stress acts upon immune response. Differently from the first model, no behavioral, physiological, or phagocytic differences were found between the two fish involved in the simultaneous model, where both fish acted as co-dominants, defending their territory. The study achieved a deeper understanding of the role of spatial exploration, territorial dominance and intraspecific interaction in gilthead seabream, and elucidated the link between them and physiological stress indicators. The results highlight aspects of interest to the aquaculture industry, showing the importance of a greater focus on rearing conditions, finding solutions to mitigate crowding effects and promoting the quality of aquacultural products
Fish Welfare in Aquaculture: Physiological and Immunological Activities for Diets, Social and Spatial Stress on Mediterranean Aqua Cultured Species
Welfare assessment currently is less well-characterized for aquatic animals and the clas-
sical methodologies used for terrestrial animals are not adequate to improve our knowledge about
fish well-being. Among different approaches, the status of organism responses can be carried out
using different physiological and biochemical tools. Here, we present the state of the art regarding
fish welfare, methodologies, and experimental results with a particular focus on two important
Mediterranean aquaculture species, Sparus aurata and Dicentrarchus labrax. We introduce an approach
using physiological stress-indicators, growth performance and swimming activity to investigate the
effects of the implantation of electronic tags to facilitate the application of telemetry for aquaculture
purposes. The application of telemetry to research on aquatic organisms has expanded recently, and
its utilization needs to be better understood. The mentioned approaches have been discussed for
application in different aquaculture methodologies. Moreover, social stress and territoriality are
relevant factors in the evaluation of gregarious species that may have consequences on the conditions
of animals farmed in captivity. These aspects, that may impair the ability of fish to respond to various
stimuli or negatively influence the flesh quality, here are analysed through behavioural observation,
flanked by the physiological and immunological approach
Muscle activity as a key indicator of welfare in farmed European sea bass (Dicentrarchus labrax L. 1758)
Groups of adult sea bass were reared at either low (10 kg m−3) or high (50 kg m−3) stocking densities respectively for 84 and 116 days. To monitor the red muscle activity, about 20 fish from both densities were surgically implanted with EMG (Electromyograms) radio transmitters, after EMG calibration during exhaustive swimming exercise (Ucrit test). Blood samples and morphometric measurements were also taken. EMG showed that the muscle activity of fish reared at 50 kg m−3 was on average twofold higher than fish kept at lower density. Cortisol was significantly more elevated at higher density and haemoglobin, haematocrit and RBCC (red blood cells count) showed the same trend, while lysozyme decreased. Patterns for glucose and lactate were less clear. The results showed that the contemporary use of functional (EMG) and physiological (haematological and biochemical) profiles could give a more comprehensive view of the fish status validating the diagnosis of fish stress induced by culture practices
Calibrating accelerometer tags with oxygen consumption rate of rainbow trout (Oncorhynchus mykiss) and their use in aquaculture facility: A case study
SIMPLE SUMMARY: Measuring metabolic rates in free-swimming fish would provide valuable insights about the energetic costs of different life activities this is challenging to implement in the field due to the difficulty of performing such measurements. Thus, the calibration of acoustic transmitters with the oxygen consumption rate (MO(2)) could be promising to counter the limitations observed in the field. In this study, calibrations were performed in rainbow trout (Oncorhynchus mykiss), and a subsample of fish was implanted with such a transmitter and then followed under aquaculture conditions. The use of acoustic transmitters calibrated with MO(2) appeared to be a promising tool to estimate energetic costs in free-swimming rainbow trout, and for welfare assessment in the aquaculture industry. ABSTRACT: Metabolic rates are linked to the energetic costs of different activities of an animal’s life. However, measuring the metabolic rate in free-swimming fish remains challenging due to the lack of possibilities to perform these direct measurements in the field. Thus, the calibration of acoustic transmitters with the oxygen consumption rate (MO(2)) could be promising to counter these limitations. In this study, rainbow trout (Oncorhynchus mykiss Walbaum, 1792; n = 40) were challenged in a critical swimming test (U(crit)) to (1) obtain insights about the aerobic and anaerobic metabolism throughout electromyograms; and (2) calibrate acoustic transmitters’ signal with the MO(2) to be later used as a proxy of energetic costs. After this calibration, the fish (n = 12) were implanted with the transmitter and were followed during ~50 days in an aquaculture facility, as a case study, to evaluate the potential of such calibration. Accelerometer data gathered from tags over a long time period were converted to estimate the MO(2). The MO(2) values indicated that all fish were reared under conditions that did not impact their health and welfare. In addition, a diurnal pattern with higher MO(2) was observed for the majority of implanted trout. In conclusion, this study provides (1) biological information about the muscular activation pattern of both red and white muscle; and (2) useful tools to estimate the energetic costs in free-ranging rainbow trout. The use of acoustic transmitters calibrated with MO(2), as a proxy of energy expenditure, could be promising for welfare assessment in the aquaculture industry
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