208 research outputs found

    Novel Silicon Photomultipliers suitable for Dual-Mirror Small-Sized Telescopes of the Cherenkov Telescope Array

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    Many of the characteristics of Silicon Photomultipliers (SiPMs), such as high Photon Detection Efficiency (PDE), are well matched to the requirements of the cameras of the Small-Sized Telescopes (SSTs) proposed for the Cherenkov Telescope Array. In fact, compared to a single mirror, the double mirror Schwarzschild Couder configuration provides a much better Point Spread Function over a large field of view. It allows better correction of aberrations at large off axis angles and facilitates the construction of compact telescopes. Moreover, the small plate scale of the dual-mirror SSTs allows the use of SiPM detectors despite their small pixel sizes. These sensors have two further advantages compared to the Photo Multipliers Tubes: the low cost and the possibility to observe in very high Night Sky Background (NSB) light level without any damage. However, one area in which SiPM performance has required improvement is Optical CrossTalk (OCT), where multiple avalanches are induced by a single impinging photon. OCT, coupled with the typical NSB rate of 25 MCnts/s per pixel during Cherenkov observations, can place severe constraints on the triggering capability of the cameras. This paper describes the performance of novel Low Voltage Reverse (LVR) 2nd and 3rd generation Multi Pixel Photon Counters manufactured by Hamamatsu Photonics. These are designed to have both enhanced PDE and reduced OCT. Two 7 x 7 mm2 S14520 LVR2 MPPCs with 75 um microcells are tested and compared with detectors of the same pixel size with 50 um microcells. A comparative analysis of a 3 x 3 mm2 S14520 LVR2 device and an S14520 LVR3 device is also carried out, demonstrating that the LVR3 gives better photon detection in the 240 380 nm wavelength range. Finally, the effect of an infrared filter on the OCT is analysed.Comment: 17 pages, 17 figures, 2 tables. Submit to NIM-A Jurna

    Wearable device for swim assessment: a new ecologic approach for communication and analysis

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    This paper describes a wearable system for the assessment of swim performance focusing on the description of the system and especially on the novel method for data transmission in water, and the algorithm used for extracting some parameters for the qualitative assessment of the performance. We placed a 3-axes Inertial Measurement Unit (IMU) on the athlete's back in a specific swimsuit, which also allows for recording 1-lead ECG. The system and the algorithm have been tested on 13 trials with 10 subjects comparing the results with data extracted from video recording. The system demonstrated able and reliable to measure time and kinematic parameters of swimming

    Nucleophosmin and its AML-associated mutant regulate c-Myc turnover through Fbw7γ

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    Mutations leading to aberrant cytoplasmic localization of nucleophosmin (NPM) are the most frequent genetic alteration in acute myelogenous leukemia (AML). NPM binds the Arf tumor suppressor and protects it from degradation. The AML-associated NPM mutant (NPMmut) also binds p19Arf but is unable to protect it from degradation, which suggests that inactivation of p19Arf contributes to leukemogenesis in AMLs. We report here that NPM regulates turnover of the c-Myc oncoprotein by acting on the F-box protein Fbw7γ, a component of the E3 ligase complex involved in the ubiquitination and proteasome degradation of c-Myc. NPM was required for nucleolar localization and stabilization of Fbw7γ. As a consequence, c-Myc was stabilized in cells lacking NPM. Expression of NPMmut also led to c-Myc stabilization because of its ability to interact with Fbw7γ and delocalize it to the cytoplasm, where it is degraded. Because Fbw7 induces degradation of other growth-promoting proteins, the NPM–Fbw7 interaction emerges as a central tumor suppressor mechanism in human cancer

    Bleaching melanin in formalin-fixed and paraffin-embedded melanoma specimens using visible light: a pilot study

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    In fluorescence microscopy, light radiation can be used to bleach fluorescent molecules in formalin-fixed and paraffin-embedded (FFPE) samples, in order to increase the ratio between signal of interest and background autofluorescence. We tested if the same principle can be exploited in bright field microscopy to bleach pigmented melanoma FFPE sections together with cell morphology maintenance. After dewaxing and rehydration, serial FFPE sections of a feline diffuse iris melanoma, a canine dermal melanoma, a gray horse dermal melanoma and a swine cutaneous melanoma were irradiated with visible light for I, 2, 3, 4 and 5 days, prior to Hematoxylin & Eosin staining. Complete bleaching was obtained after 1-day treatment in feline and swine melanomas, while 2 and 3 days were required in canine and equine neoplasms, respectively. In all treated samples, cell morphology was maintained. Photo-induced bleaching combined with immunohistochemistry was tested after a 3-day photo-treatment using five different markers. According to the literature, in all samples neoplastic cells stained positive for vimentin, S100 and PNL2, while negative for FVIII and pancytokeratin. in conclusion, visible light can be effectively exploited to bleach pigmented melanoma FFPE sections prior to perform routine histochemical and immunohistochemical stains

    Mechanical ventilation and volutrauma: study in vivo of a healthy pig model

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    Mechanical ventilation is essential in intensive care units. However, it may itself induce lung injury. Current studies are based on rodents, using exceptionally large tidal volumes for very short periods, often after a "priming" pulmonary insult. Our study deepens a clinically relevant large animal model, closely resembling human physiology and the ventilator setting used in clinic settings. Our aim was to evaluate the pathophysiological mechanisms involved in alveolo/capillary barrier damage due to mechanical stress in healthy subjects. We randomly divided 18 pigs (sedated with medetomidine/tiletamine-zolazepam and anesthetised with thiopental sodium) into three groups (n=6): two were mechanically ventilated (tidal volume of 8 or 20 ml/kg), the third breathed spontaneously for 4 hours, then animals were sacrifi ced (thiopental overdose). We analyzed every 30' hemogasanalysis and the main circulatory and respiratory parameters. Matrix gelatinase expression was evaluated on bronchoalveolar lavage fl uid after surgery and before euthanasia. On autoptic samples we performed zymographic analysis of lung, kidney and liver tissues and histological examination of lung. Results evidenced that high V T evoked profound alterations of lung mechanics and structure, although low V T strategy was not devoid of side effects, too. Unexpectedly, also animals that were spontaneously breathing showed a worsening of the respiratory functions

    Investigating on Besnoitia besnoiti (Apicomplexa, Sarcocystidae) in naturally infected dairy cattle by an integrated approach.

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    Bovine besnoitiosis, caused by Besnoitia besnoiti, is a (re)emerging disease in Europe (Cortes et al., 2014), including Italy (Gazzonis et al., 2014; 2017). However, its economic impact is scarcely considered and generally underestimated and there are still little studied aspects concerning both the parasite and the disease. Following a natural outbreak of besnoitiosis in a dairy herd, a study was planned to characterize B. besnoiti infection in cattle through a multidisciplinary approach.Suspicious abortions and clinical cases of besnoitiosis were reported in a dairy farm (September 2017, Northern Italy) housing 216 Holstein cattle. Blood samples were collected; haematological and serological analyses (ELISA and confirmatory WB) were performed (Fernandez-Garcia et al., 2009). Histology and molecular (endpoint ITS-1 PCR (Cortes et al., 2007) and sequencing) analyses of tissues from a slaughtered cow with chronic besnoitiosis were carried out. Out of 59 ELISA-positive animals, 50 (23%) were confirmed by WB. B. besnoiti prevalence was higher in cows (41%) than in calves (12%); any heifer did not result positive. Considering haematological parameters, a significant shift in the differential leucocyte formula from lymphocyte to granulocyte was recorded in infected cows (Mean±S.D.:L=46.1±18.4,G=53.9±18.4) if compared to negative animals (Student’s T-test,p=0.012). This finding could be helpful in diagnosis, treatment and control of besnoitiosis. Histology revealed a high load of B. besnoiti tissue cysts in skin, vulva, muzzle, sclera, eyelid, respiratory tract, emphasizing the possibility of parasite transmission through direct contact among animals. B. besnoiti was confirmed by PCR in other organs (heart, liver, aorta wall, tonsil) and especially in ovary, uterus and vulva, suggesting that the infection could affect cows’ fertility. Parasite DNA was also found in masseters posing an important question for food security, even if B. besnoiti is not considered zoonotic. The study suggests that to investigate the dynamics of bovine besnoitiosis is mandatory associate clinical and laboratory tests, including the genetic characterization of the parasite and its eventual correlation with the disease outcome

    Effect of late gadolinium enhancement on left atrial impairment in myocarditis patients

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    ObjectiveThe aims of our study were to investigate the effect of the extent and location of late gadolinium enhancement (LGE) on the left atrium (LA) function in patients with acute myocarditis (AM) using cardiovascular magnetic resonance (CMR).MethodThis retrospective study performed CMR scans in 113 consecutive patients (89 males, 24 females; mean age 45.8 & PLUSMN; 17.3 years) with AM that met the updated Lake Louise criteria. Reservoir, conduit, and booster LA functions were analyzed by CMR feature tracking using dedicated software. Besides LA strain measurements, myocardial scar location and extent were assigned and quantified by LGE imaging.ResultsAM patients with septal LGE had impaired reservoir, conduit, and conduit strain rate function in comparison with AM patients with non-septal LGE (p = 0.001, for all). In fully adjusted multivariable linear regression, reservoir and conduit were significantly associated with left ventricle (LV) LGE location (& beta; coefficient = 8.205, p = 0.007; & beta; coefficient = 5.185, p = 0.026; respectively). In addition, LA parameters decreased according to the increase in the extent of LV fibrosis (LGE & LE; 10%; LGE 11-19%; LGE & GE; 20%). After adjustment in multivariable linear regression, the association with LV LGE extent was no longer statistically significant.ConclusionIn patients with acute myocarditis, LA function abnormalities are significantly associated with LV LGE location, but not with LGE extent. Septal LGE is paralleled by a deterioration of LA reservoir and conduit function.Clinical relevance statementLeft atrium dysfunction is associated with the presence of late gadolinium enhancement in the left ventricle septum and can be useful in the clinical prognostication of patients with acute myocarditis, allowing individually tailored treatment.Key Points & BULL; Myocardial fibrosis is related to atrial impairment.& BULL; The location of myocardial fibrosis is the main determinant of atrial dysfunction in myocarditis patients.& BULL; The quantification of atrial mechanisms may provide more in-depth insight into myocarditis pathophysiology.Key Points & BULL; Myocardial fibrosis is related to atrial impairment.& BULL; The location of myocardial fibrosis is the main determinant of atrial dysfunction in myocarditis patients.& BULL; The quantification of atrial mechanisms may provide more in-depth insight into myocarditis pathophysiology.Key Points & BULL; Myocardial fibrosis is related to atrial impairment.& BULL; The location of myocardial fibrosis is the main determinant of atrial dysfunction in myocarditis patients.& BULL; The quantification of atrial mechanisms may provide more in-depth insight into myocarditis pathophysiology

    Atrial and ventricular strain using cardiovascular magnetic resonance in the prediction of outcomes of pericarditis patients: a pilot study

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    Objective Our study aimed to explore with cardiovascular magnetic resonance (CMR) the impact of left atrial (LA) and left ventricular (LV) myocardial strain in patients with acute pericarditis and to investigate their possible prognostic signifcance in adverse outcomes. Method This retrospective study performed CMR scans in 36 consecutive patients with acute pericarditis (24 males, age 52 [23–52]). The primary endpoint was the combination of recurrent pericarditis, constrictive pericarditis, and surgery for pericardial diseases defned as pericardial events. Atrial and ventricular strain function were performed on conventional cine SSFP sequences. Results After a median follow-up time of 16 months (interquartile range [13–24]), 12 patients with acute pericarditis reached the primary endpoint. In multivariable Cox regression analysis, LA reservoir and LA conduit strain parameters were all independent determinants of adverse pericardial diseases. Conversely, LV myocardial strain parameters did not remain an independent predictor of outcome. With receiving operating characteristics curve analysis, LA conduit and reservoir strain showed excellent predictive performance (area under the curve of 0.914 and 0.895, respectively) for outcome prediction at 12 months. Conclusion LA reservoir and conduit mechanisms on CMR are independently associated with a higher risk of adverse pericardial events. Including atrial strain parameters in the management of acute pericarditis may improve risk stratifcation. Clinical relevance statement Atrial strain could be a suitable non-invasive and non-contrast cardiovascular magnetic resonance parameter for predicting adverse pericardial complications in patients with acute pericarditis

    Assessment of the indoor odour impact in a naturally ventilated room

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    Indoor air quality influences peopleâ\u80\u99s lives, potentially affecting their health and comfort. Nowadays, ventilation is the only technique commonly used for regulating indoor air quality. CO2 is the reference species considered in order to calculate the air exchange rates of indoor environments. Indeed, regarding air quality, the presence of pleasant or unpleasant odours can strongly influence the environmental comfort. In this paper, a case study of indoor air quality monitoring is reported. The indoor field tests were conducted measuring both CO2 concentration, using a photoacoustic multi-gas analyzer, and odour trends, using an electronic nose, in order to analyze and compare the information acquired. The indoor air monitoring campaign was run for a period of 20 working days into a university room. The work was focused on the determination of both CO2 and odour emission factors (OEF) emitted by the human activity and on the evaluation of the odour impact in a naturally ventilated room. The results highlighted that an air monitoring and recycling system based only on CO2 concentration and temperature measurements might be insufficient to ensure a good indoor air quality, whereas its performances could be improved by integrating the existing systems with an electronic nose for odour detection
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