164 research outputs found

    Cubesat mission with technological demonstrator payload for high data rate downlink and health monitoring

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    The HyperCube payload will be composed by two different technological experiment, an high data-rate C band antenna, and a demonstrator for a remote structural health monitoring system. The first one has been thought with the aim to give Cubesats the capability to download an high quantity of data; it could be useful either if the data requiring the high data-rate downlink is on-board generated or simply retransmitted. The applications for which this payload could be used are several; an example for the first category of application is to download the data generated by another payload; the high data-rate capability could be necessary due to the narrow visibility window with the ground station, affected also by the absence of an active AOCS subsystem, which makes difficult the alignment of the on board antenna with the ground one. But the C band antenna could also be used to act as a “space–repeater”, downloading up–linked information. The second payload is related to the need to take under strictly control the health of the structures (not only the ones strictly belonging to primary structures, but also that of any subsystem component). In order to do that, smart materials are integrated into the structural component that need to be monitored; in particular, piezoelectric patches are used as sensors. As the structure is stressed, and the integrated piezoelectric sensors are subjected to mechanical deformation, they produce an electric signal; acquiring and properly studying the produced signal it is possible to monitor the mechanical condition of the structures. The health monitoring system is completed by a MicroController Unit which acquires, samples and stores the signal produced, and a transmitting system, which could be the C band antenna, or the TT&C antenna which each satellite needs

    Study on an air-launched constellation of tactical micro-satellites for defence Use

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    The great attention on air-launched microsatellites is due on one hand to the possibilities given by the miniaturization push, making the same performances of traditional satellites achievable with smaller systems, and on the other hand to the disruptive advantages allowed by air-launch techniques, providing Italy not only with an autonomous launch capability, but also with the flexibility to choose the orbit inclination and the launch time, enabling a responsive approach at lower costs respect to ground based launches. In this study, several issues related to this subject are analyzed. A constellation of four microsatellites for electro-optical Earth Observation (EO) is conceived, namely ITAFμSAT (i.e. ITalian Tactical Formation of μ-SATellites). ITAFμSAT is designed to achieve a sub-metric spatial resolution and to offer a high revisit frequency on a specified target area to satisfy military needs. ITAFμSAT is designed to be responsive and the system is conceived to guarantee a fast access to space since the mission is called, through a Plug-and-Play (PnP) approach; to provide Italy with a proprietary system, built, launched and operated on-purpose for its contingent needs; and to complete the information supplied by other EO systems with high quality images captured in a very short time

    Haemophilus aphrophilus Endocarditis after Tongue Piercing

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    Piercing invades subcutaneous areas and has a high potential for infectious complications. The number of case reports of endocarditis associated with piercing is increasing. We studied a 25-year-old man with a pierced tongue, who arrived at Memorial Health University Medical Center with fever, chills, rigors, and shortness of breath of 6 days duration and had an aortic valvuloplasty for correction of congenital aortic stenosis

    In vitro effects of tyre debris organic extract on the kinetic and morphologic traits of rabbit spermatozoa

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    [EN] The present study aims at evaluating the effects of the organic extract of tyre debris (TDOE) from tyre wear on the kinetic and morphologic features of rabbit spermatozoa. Rabbit sperm were incubated for 4 h with 0, 5, 10, 50 and 75 ¿g/mL of TDOE. Sperm motility was evaluated by computer-assisted semen analysis. Phosphatidilcholine (PS) externalization (apoptosis) and plasma membrane breakage (necrosis) were assessed using the annexinV/propidium iodide assay. The sperm ultrastructure was observed by scanning (SEM) and transmission electron microscopy (TEM). A relevant decrease in the motility rate, PS externalization, and in plasma membrane breakage of spermatozoa were observed after incubation with TDOE at concentrations higher than 50 ¿g/mL. The most frequent ultrastructural anomalies detected in the analysed specimens were: plasma and/or acrosomal membrane breakage, swollen and disorganized mitochondria, and altered axonemal patterns. Taken together, these results suggest that the organic extract of tyre debris can be toxic to rabbit spermatozoa ¿ affecting their movement and structural integrity ¿ when present in seminal plasma at a concentrations higher than 50 ¿g/mL. Although rabbit sperm has been proven to be a suitable model for testing the in vitro effects of many chemical compounds, including TDOE, the obtained results must be considered preliminary and cannot be extrapolated yet to the in vivo outcomes because of scanty data. The results encourage, however, further research in this field.Supported by the PROLIFE Flagship project, city of Milan, ItalyMoretti, E.; Dal Bosco, A.; Mourvaki, E.; Cardinali, R.; Collodel, G.; Geminiani, M.; Cetta, F.... (2009). In vitro effects of tyre debris organic extract on the kinetic and morphologic traits of rabbit spermatozoa. World Rabbit Science. 17(4):213-220. doi:10.4995/wrs.2009.64621322017

    A diastrophic dysplasia sulfate transporter (SLC26A2) mutant mouse: morphological and biochemical characterization of the resulting chondrodysplasia phenotype.

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    Mutations in the diastrophic dysplasia sulfate transporter (DTDST or SLC26A2) cause a family of recessively inherited chondrodysplasias including, in order of decreasing severity, achondrogenesis 1B, atelosteogenesis 2, diastrophic dysplasia (DTD) and recessive multiple epiphyseal dysplasia. The gene encodes a widely distributed sulfate/chloride antiporter of the cell membrane whose function is crucial for the uptake of inorganic sulfate, which is needed for proteoglycan sulfation. To provide new insights in the pathogenetic mechanisms leading to skeletal and connective tissue dysplasia and to obtain an in vivo model for therapeutic approaches to DTD, we generated a Dtdst knock-in mouse with a partial loss of function of the sulfate transporter. In addition, the intronic neomycine cassette in the mutant allele contributed to the hypomorphic phenotype by inducing abnormal splicing. Homozygous mutant mice were characterized by growth retardation, skeletal dysplasia and joint contractures, thereby recapitulating essential aspects of the DTD phenotype in man. The skeletal phenotype included reduced toluidine blue staining of cartilage, chondrocytes of irregular size, delay in the formation of the secondary ossification center and osteoporosis of long bones. Impaired sulfate uptake was demonstrated in chondrocytes, osteoblasts and fibroblasts. In spite of the generalized nature of the sulfate uptake defect, significant proteoglycan undersulfation was detected only in cartilage. Chondrocyte proliferation and apoptosis studies suggested that reduced proliferation and/or lack of terminal chondrocyte differentiation might contribute to reduced bone growth. The similarity with human DTD makes this mouse strain a useful model to explore pathogenetic and therapeutic aspects of DTDST-related disorders

    Extra-Intestinal Manifestations of Familial Adenomatous Polyposis

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    Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited disorder, which results from a germ line mutation in the APC (adenomatous polyposis coli) gene. FAP is characterized by the formation of hundreds to thousands of colorectal adenomatous polyps. Although the development of colorectal cancer stands out as the most prevalent complication, FAP is a multisystem disorder of growth. This means, it is comparable to other diseases such as the MEN syndromes, Von Hippel-Lindau disease and neurofibromatosis. However, the incidence of many of its clinical features is much lower. Therefore, a specialized multidisciplinary approach to optimize health care—common for other disorders—is not usually taken for FAP patients. Thus, clinicians that care for and counsel members of high-risk families should have familiarity with all the extra-intestinal manifestations of this syndrome. FAP-related complications, for which medical attention is essential, are not rare and their estimated lifetime risk presumably exceeds 30%. Affected individuals can develop thyroid and pancreatic cancer, hepatoblastomas, CNS tumors (especially medulloblastomas), and various benign tumors such as adrenal adenomas, osteomas, desmoid tumors and dental abnormalities. Due to improved longevity, as a result of better prevention of colorectal cancer, the risk of these clinical problems will further increase

    Laser-induced modification of the patellar ligament tissue: comparative study of structural and optical changes

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    The effects of non-ablative infrared (IR) laser treatment of collagenous tissue have been commonly interpreted in terms of collagen denaturation spread over the laser-heated tissue area. In this work, the existing model is refined to account for the recently reported laser-treated tissue heterogeneity and complex collagen degradation pattern using comprehensive optical imaging and calorimetry toolkits. Patella ligament (PL) provided a simple model of type I collagen tissue containing its full structural content from triple-helix molecules to gross architecture. PL ex vivo was subjected to IR laser treatments (laser spot, 1.6 mm) of equal dose, where the tissue temperature reached the collagen denaturation temperature of 60 ± 2°C at the laser spot epicenterin the first regime, and was limited to 67 ± 2°C in the second regime. The collagen network was analyzed versus distance from the epicenter. Experimental characterization of the collagenous tissue at all structural levels included cross-polarization optical coherence tomography, nonlinear optical microscopy, light microscopy/histology, and differential scanning calorimetry. Regressive rearrangement of the PL collagen network was found to spread well outside the laser spot epicenter (>2 mm) and was accompanied by multilevel hierarchical reorganization of collagen. Four zones of distinct optical and morphological properties were identified, all elliptical in shape, and elongated in the direction perpendicular to the PL long axis. Although the collagen transformation into a random-coil molecular structure was occasionally observed, it was mechanical integrity of the supramolecular structures that was primarily compromised. We found that the structural rearrangement of the collagen network related primarily to the heat-induced thermo-mechanical effects rather than molecular unfolding. The current body of evidence supports the notion that the supramolecular collagen structure suffered degradation of various degrees, which gave rise to the observed zonal character of the laser-treated lesion

    Microsatellite instability in thyroid tumours and tumour-like lesions

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    Fifty-one thyroid tumours and tumour-like lesions were analysed for instability at ten dinucleotide microsatellite loci and at two coding mononucleotide repeats within the transforming growth factor β (TGF-β) type II receptor (TβRII) and insulin-like growth factor II (IGF-II) receptor (IGFIIR) genes respectively. Microsatellite instability (MI) was detected in 11 out of 51 cases (21.5%), including six (11.7%) with MI at one or two loci and five (9.8%) with Ml at three or more loci (RER+ phenotype). No mutations in the TβRII and IGFIIR repeats were observed. The overall frequency of MI did not significantly vary in relation to age, gender, benign versus malignant status and tumour size. However, widespread MI was significantly more frequent in follicular adenomas and carcinomas than in papillary and Hürthle cell tumours: three out of nine tumours of follicular type (33.3%) resulted in replication error positive (RER+), versus 1 out of 29 papillary carcinomas (3.4%, P = 0.01), and zero out of eight Hürthle cell neoplasms. Regional lymph node metastases were present in five MI-negative primary cancers and resulted in MI-positive in two cases. © 1999 Cancer Research Campaig
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