226 research outputs found
Statistical Analysis of Differential Group Delay in Few-Mode Spun Optical Fiber
This thesis proposes a statistical analysis of the differential group delay in few-mode optical fibers. The numerical analysis is performed by an accurate modeling of the propagation and coupling of a few-mode fiber, supporting the first 4 LP groups, perturbed by stress birefringence and core ellipticity and spun with a sinusoidal profile.ope
Morphological and Receptorial Changes in the Epididymal Adipose Tissue of Rats Subjected to a Stressful Stimulus.
Obesity is nowadays related to other pathological conditions such as inflammation, insulin resistance, and diabetes, but little is known about the relationship between psychological stress and adipocytes. We decided to study the expression of the translocator protein (TSPO) 18-kDa, peroxisome proliferator-activated receptor-\u3b3 (PPAR-\u3b3), mitochondrial uncoupling protein-1 (UCP-1), and adipocyte morphology in the adipose tissue of rats subjected to stress conditions. In our model of stress, rats fasted for 24 h were placed in a restraint cage and then immersed vertically to the level of the xiphoid process in a water bath at 23 \ub0C for 7 h. After that period, we removed the epididymal adipose tissues for the subsequent analysis. The optical and electron microscopy revealed that adipocytes of control rats formed a continuous epithelial-like cell layer; on the contrary in the adipocytes of stressed rats some cells have merged together and the number of vessels formed seems to increase. Stressed adipocytes presented unilocular cells with numerous mitochondria with a morphology ranging between that of brown adipose tissue (BAT) and white adipose tissue (WAT). Interestingly, when we investigated the subcellular distribution of UCP-1 by immunogold electron microscopy, the adipose tissue of stressed rats was positive for UCP-1. From the immunoblot analysis with anti-PPAR-\u3b3 antibody, we observed an increased expression of PPAR-\u3b3 in the adipocytes of stressed group compared with control group (P < 0.05). Stress induced the expression of TSPO 18-kDa receptor (B(max) = 106.45 \ub1 5.87 fmol/mg proteins), which is undetectable by saturation-binding assay with [(3)H]PK 11195 in the control group
Gas Sorption and Diffusion in Amorphous and Semicrystalline Nanoporous Poly(2,6-dimethyl-1,4-phenylene)oxide
In this contribution is presented an analysis of mass transport
properties of low molecular weight compounds in amorphous PPO and in two semicrystalline PPOs obtained by treating with benzene and carbon tetrachloride the amorphous sample. It is found that semicrystalline samples are endowed with larger gas sorption capacity and diffusivity as compared to the amorphous ones: this behavior has been attributed prevalently to the nanoporous nature of the crystalline phases induced by treatment with solvents. In particular, sorption experiments, carried out at 30 °C with methane, carbon dioxide, propane and propylene, have shown that both semicrystalline PPOs display rather interesting features which make them suitable for use as membrane materials in gas separation processes, in view of the relatively high values of solubility and diffusivity. Moreover, these peculiar sorption and mass transport properties have been found to be virtually unaffected by thermal aging: in fact, sorption experiments conducted on amorphous and semicrystalline PPO
after treatment at 65 °C for three months showed that sorption and transport properties of aged samples are the same as for the
untreated ones. This is an important feature to ensure the stability of performances in membrane applications
The influence of a new clinical motion for endodontic instruments on the incidence of postoperative pain
Previous studies showed that motor motions play an important role in determining apical extrusion of debris. Therefore a new clinical motion (MIMERACI) has been proposed. The basic idea is to progress slowly (1mm advancement), and after each 1mm, to remove the instrument from the canal, clean flutes and irrigate. The aim of the study was to prove whether the clinical use of MIMERACI technique would influence or not postoperative pain.MATERIALS AND METHODS:
100 teeth requesting endodontic treatment were selected for the study and divided into two similar groups based on anatomy, pre-operative symptoms and vitality, presence or absence of periapical lesion. All teeth were shaped, cleaned and obturated by the same operator, using the same NiTi instruments. The only difference between the two groups was the instrumentation technique: tradional (group A) vs MIMERACI (group B). Assessment of postoperative pain was performed 3 days after treatment. Presence, absence and degree of pain were recorded with a visual analogue scale (VAS), validated in previous studies. Collected data statistically analyzed using one-way ANOVA post hoc Tukey test.
RESULTS:
For VAS pain scores MIMERACI technique showed significantly better results than group A (p=0,031). Overall, both incidence and intensity of symptoms were significantly lower. Flare ups occurred in 3 patients, but none treated with the MIMERACI Technique.
CONCLUSIONS:
Since extruded debris can elicit more postoperative pain, results obtained by using MIMERACI technique are probably due to many factors: better mechanical removal and less production of debris and more efficient irrigation during instrumentation
Analysis of modal coupling due to birefringence and ellipticity in strongly guiding ring-core OAM fibers
After briefly recalling the issue of OAM mode purity in strongly-guiding ring-core
fibers, this paper provides a methodology to calculate the coupling strength between OAM mode
groups due to fiber perturbations. The cases of stress birefringence and core ellipticity are
theoretically and numerically investigated. It is found that both perturbations produce the same
coupling pattern among mode groups, although with different intensities. The consequence is
that birefringence causes the highest modal crosstalk because it strongly couples groups with a
lower propagation-constant mismatch. The power coupling to parasitic TE and TM modes is also
quantified for both perturbations and is found to be non-negligible. Approximate modal crosstalk
formulas valid for weakly-guiding multi-core fibers, but whose parameters are adapted to the
present case of strongly guiding OAM fibers, are found to provide a reasonable fit to numerical
results. Finally, the effect that modal coupling has on OAM transmission is assessed in terms of
SNR penalty
Depressive symptoms and cognitive/functional status in a sample of elderly subjects referring to a memory clinic
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Experimental investigation on camera calibration for 3D photogrammetric scanning of micro-features for micrometric resolution
[EN] Recently, it has been demonstrated that photogrammetry can be used for the measurement of small objects with micro-features, with good results and lower cost, compared to other established techniques such as interferometry, conoscopic holography, and 3D microscopy.
Calibration is a critical step in photogrammetry and the classical pinhole camera model has been tested for magnifications lower than 2×. At higher magnification levels, because of the reduction of the depth of field (DOF), images can lead to calibration data with low reprojection errors. However, this could lead to bad results in the 3D reconstruction.
With the aim of verifying the possibility of applying the camera model to magnifications higher than 2×, experiments have been conducted using reflex cameras with 60 mm macro lens, equipped with the combination of three extension tubes, corresponding to 2.06, 2.23, and 2.4 magnification levels, respectively.
Experiments consisted of repeating calibration five times for each configuration and testing each calibration model, measuring two artifacts with different geometrical complexity. The calibration results have shown good repeatability of a subset of the internal calibration parameters. Despite the differences in the calibration reprojection error (RE), the quality of the photogrammetric 3D models retrieved was stable and satisfying.
The experiment demonstrated the possibilities of the photogrammetric system presented, equipped to very high magnification levels, to retrieve accurate 3D reconstruction of micro-features with uncertainties of few micrometers, comparable with industry s expensive state-of-the-art technologies.Percoco, G.; Guerra, MG.; Sánchez Salmerón, AJ.; Galantucci, LM. (2017). Experimental investigation on camera calibration for 3D photogrammetric scanning of micro-features for micrometric resolution. The International Journal of Advanced Manufacturing Technology. 91(9-12):2935-2947. https://doi.org/10.1007/s00170-016-9949-6S29352947919-12Uhlmann E, Mullany B, Biermann D, Rajurkar KP, Hausotte T, Brinksmeier E (2016) Process chains for high-precision components with micro-scale features. CIRP Ann - Manuf Technol 65:549–572. doi: 10.1016/j.cirp.2016.05.001Savio E, De Chiffre L, Schmitt R (2007) Metrology of freeform shaped parts. 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Characteristics of Nondisabled Older Patients Developing New Disability Associated with Medical Illnesses and Hospitalization
OBJECTIVE: To identify demographic, clinical, and biological characteristics of older nondisabled patients who develop new disability in basic activities of daily living (BADL) during medical illnesses requiring hospitalization. DESIGN: Longitudinal observational study. SETTING: Geriatric and Internal Medicine acute care units. PARTICIPANTS: Data are from 1,686 patients aged 65 and older who independent in BADL 2 weeks before hospital admission, enrolled in the 1998 survey of the Italian Group of Pharmacoepidemiology in the Elderly Study. MEASUREMENTS: Study outcome was new BADL disability at time of hospital discharge. Sociodemographic, functional status, and clinical characteristics were collected at hospital admission; acute and chronic conditions were classified according to the International Classification of Disease, ninth revision; fasting blood samples were obtained and processed with standard methods. RESULTS: At the time of hospital discharge 113 patients (6.7%) presented new BADL disability. Functional decline was strongly related to patients’ age and preadmission instrumental activities of daily living status. In a multivariate analysis, older age, nursing home residency, low body mass index, elevated erythrocyte sedimentation rate, acute stroke, high level of comorbidity expressed as Cumulative Illness Rating Scale score, polypharmacotherapy, cognitive decline, and history of fall in the previous year were independent and significant predictors of BADL disability. CONCLUSION: Several factors might contribute to loss of physical independence in hospitalized older persons. Preexisting conditions associated with the frailty syndrome, including physical and cognitive function, comorbidity, body composition, and inflammatory markers, characterize patients at high risk of functional decline
Degustación comparativa por parte de consumidores de kiwi. Primera parte
Entre el 21 y el 23 del mes de octubre del año 2020, en la Ciudad de Mar del Plata-Argentina, se llevó a cabo una degustación por parte de consumidores de kiwi, no expertos, no entrenados, quienes debieron contrastar productos nacionales -procedentes del Sudeste de la Provincia de Buenos Aires- y chilenos. El objetivo general fue profundizar el conocimiento de las percepciones y elecciones de los consumidores mediante la valoración de los atributos de calidad del producto. A tal fin, los participantes de la experiencia evaluaron globalmente muestras de fruta y atributos particulares como el "sabor", el "color de la pulpa", el "aroma", "la consistencia/firmeza de la pulpa" y la "apariencia externa", observando y degustando las mismas. Además, con base en un formulario de encuesta complementario, fueron consultados respecto a sus preferencias y disposición a pagar (DAP) por los kiwis regionales y extranjeros.EEA BalcarceFil: Berges, Miriam. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: LupÃn, Beatriz. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: RodrÃguez, Julieta. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Yommi, Alejandra Karina. Instituto Nacional de TecnologÃa Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Cincunegui, Carmen. Universidad Provincial del Sudoeste; Argentina. Comisión de Investigaciones CientÃficas. Centro de Emprendedorismo y Desarrollo Territorial Sostenible; Argentina.Fil: Cincunegui, Carmen. Universidad Nacional del Sur. Departamento de Ciencias de la Administración; Argentina.Fil: Cendón, MarÃa Laura. Instituto Nacional de TecnologÃa Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Ariza, Cristian Mariano. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Roldán, Camila. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Urquiza Jozami, Gonzalo. Universidad Argentina de la Empresa; Argentina.Fil: Agullo, Agustina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Brillanti, Carla. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Cutrera, Gianluca. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Menéndez, Luciano. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Pérez Guerra, Juan José Jesús Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina
Degustación comparativa por parte de consumidores de kiwi. Primera parte
Entre el 21 y el 23 del mes de octubre del año 2020, en la Ciudad de Mar del Plata-Argentina, se llevó a cabo una degustación por parte de consumidores de kiwi, no expertos, no entrenados, quienes debieron contrastar productos nacionales -procedentes del Sudeste de la Provincia de Buenos Aires- y chilenos. El objetivo general fue profundizar el conocimiento de las percepciones y elecciones de los consumidores mediante la valoración de los atributos de calidad del producto. A tal fin, los participantes de la experiencia evaluaron globalmente muestras de fruta y atributos particulares como el "sabor", el "color de la pulpa", el "aroma", "la consistencia/firmeza de la pulpa" y la "apariencia externa", observando y degustando las mismas. Además, con base en un formulario de encuesta complementario, fueron consultados respecto a sus preferencias y disposición a pagar (DAP) por los kiwis regionales y extranjeros.Fil: Berges, Miriam. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: LupÃn, Beatriz. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: RodrÃguez, Julieta A. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Yommi, Alejandra. Instituto Nacional de TecnologÃa Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Cincunegui, Carmen. Universidad Nacional del Sur. Departamento de Ciencias de la Administración; Argentina.Fil: Cendón, MarÃa Laura. Instituto Nacional de TecnologÃa Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Ariza, Cristian Mariano. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Urquiza Jozami, Gonzalo Martin. JILAEE. UADE; Argentina.Fil: Roldán, Camila. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Agullo, Agustina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Brillanti, Carla. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Cutrera, Gianluca. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Menéndez, Luciano. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Pérez Guerra, Juan José Jesús. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina
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