1,950 research outputs found
Estimation of User's Orientation via Wearable UWB
User's orientation in indoor environments is an important part of her context. Orientation can be useful to understand what the user is looking at, and thus to improve the interaction between her and the surrounding environment. In this paper, we present a method based on wearable UWB-enabled devices. The position of the devices in space is used to estimate the user's orientation. We experimentally evaluated the impact of some operational parameters, such as the distance between worn devices, or some environmental conditions, such as the position of the user in the room. Results show that the accuracy of the method suits the needs of a wide range of practical purposes
Pathogenic Aβ A2V versus protective Aβ A2T mutation : early stage aggregation and membrane interaction
We investigated the effects of punctual A-to-V and A-to-T mutations in the amyloid precursor protein APP, corresponding to position 2 of A\u3b21\u201342. Those mutations had opposite effects on the onset and progression of Alzheimer disease, the former inducing early AD pathology and the latter protecting against the onset of the disease. We applied Static and Dynamic Light Scattering and Circular Dichroism, to study the different mutants in the early stages of the aggregation process, essential for the disease. Comparative results showed that the aggregation pathways differ in the kinetics and extent of the process, in the size of the aggregates and in the evolution of the secondary structure, resulting in fibrils of different morphology, as seen by AFM. Mutated peptides had comparable toxic effects on N2a cells. Moreover, as assessed by X-ray scattering, all of them displayed disordering effects on the internal structure of mixed phospholipids-gangliosides model membranes
Uniaxial traction test on human gracilis and semitendinous tendon
The use of isolated human tendons as well as in associated forms on knee reconstrution has become na usual practice. The literature reveals that the use of implants of patellar tendon as well as the double semitendinous tendon associated to the double gracilis tendon exhibits different post surgical evolution related to the minimal extension loss, anterior-posterior displacement (KT-1000 artrometer), as well as to the sport activities. This research work aim to analyze the mechanical behavior of human tendons (gracilis and semitendinous) subject to uniaxial traction to failure. The mechanical parameters considered includes: stress at failure (MPa), strain energy at failure (N.mm) and strain rate (mm/mm). Results induced to the following conclusions: - tendon of semitendinous muscle is more resistent than the tendon gracilis muscle; exhibits lower strain, stores higher level of strain energy at failure. - as they present distinct mechanical behavior, it would be necessary to acomplish a more detaield analysis to face the time and history dependence wich are the basic characteristics of viscoelastic materials.O uso de tendões humanos, de forma isolada ou associada, em reconstruções ligamentares do joelho é uma prática usual. A utilização desses enxertos (tendão patelar, duplo semitendinoso associado ao duplo grácil) apresenta evolução pós-operatória diferente, quando analisados os parâmetros : perda mínima da extensão, deslocamento ântero-posterior (artrômetro KT-2000), retorno as atividades esportivas. A presente pesquisa tem por objetivo analisar o comportamento mecânico de tendões humanos (grácil e semitendinoso), quando submetidos a ensaios uniaxiais de tração, até a ruptura. Como parâmetros mecânicos para análise e confronto foram considerados: tensão de ruptura (MPa), deformação relativa, módulo de elasticidade (MPa), energia de ruptura (N.mm) e velocidade de carregamento (mm/s). Os resultados permitiram concluir que: - o tendão do músculo semitendinoso é mais resistente que o tendão do músculo grácil; apresenta menores deformações relativas; acumula maior energia de ruptura; - a utilização destes tendões como enxerto único, impõe uma análise mecânica mais detalhada, pois apresentam comportamento mecânico distinto e são materiais história e tempo - dependentes (viscoelásticos).51
Connective tissue anomalies in patients with spontaneous cervical artery dissection.
OBJECTIVE: To investigate the prevalence of connective tissue abnormalities in patients with spontaneous cervical artery dissections (sCeAD). METHODS: We systematically assessed clinically detectable signs of connective tissue aberration in a series of consecutive patients with sCeAD and of age- and sex-matched patients with ischemic stroke unrelated to CeAD (non-CeAD IS) by a standard examination protocol including 68 items, and performed extensive molecular investigation for hereditary connective tissue disorders in all patients with sCeAD. RESULTS: The study group included 84 patients with sCeAD (mean age, 44.5 ± 7.8 years; 66.7% men) and 84 patients with non-CeAD IS. None of the patients with sCeAD met clinical or molecular diagnostic criteria for established hereditary connective tissue disorder. Connective tissue abnormalities were detected more frequently in the group of patients with sCeAD than in the group of those with non-CeAD IS (mean number of pathologic findings, 4.5 ± 3.5 vs 1.9 ± 2.3; p < 0.001). Eighty-one patients (96.4%) in the sCeAD group had at least one detectable sign compared with 55 patients (66.7%) in the group with non-CeAD IS (p < 0.001). Skeletal, ocular, and skin abnormalities, as well as craniofacial dysmorphisms, were the clinical signs more strongly associated with sCeAD. Signs suggesting connective tissue abnormality were also more frequently represented in patients with sCeAD than in patients with traumatic CeAD (28.6%, p < 0.001; mean number of pathologic findings, 1.7 ± 3.7, p = 0.045). CONCLUSIONS: Connective tissue abnormalities are frequent in patients with sCeAD. This reinforces the hypothesis that systemic aberrations of the connective tissue might be implicated in the pathogenesis of the disease
Antithrombotic medications and the etiology of intracerebral hemorrhage: MUCH-Italy.
23noOBJECTIVE:
To test the hypothesis that the effect of antithrombotic medications on the risk of intracerebral hemorrhage (ICH) varies according to the location of the hematoma.
METHODS:
Consecutive patients with ICH were enrolled as part of the Multicenter Study on Cerebral Hemorrhage in Italy (MUCH-Italy). Multivariable logistic regression models served to examine whether risk factors for ICH and location of the hematoma (deep vs lobar) predict treatment-specific ICH subgroups (antiplatelets-related ICH and oral anticoagulants [OACs]-related ICH).
RESULTS:
A total of 870 (313 lobar ICH, 557 deep ICH) subjects were included. Of these, 223 (25.6%) were taking antiplatelets and 77 (8.8%) OACs at the time of stroke. The odds of antiplatelet-related ICH increased with aging (odds ratio [OR] 1.05; 95% confidence interval [CI] 1.03-1.07) and hypertension (OR 1.86; 95% CI 1.22-2.85) but had no relation with the anatomical location of ICH. Conversely, lobar location of the hematoma was associated with the subgroup of OAC-related ICH (OR 1.70; 95% CI 1.03-2.81) when compared to the subgroup of patients taking no antithrombotic medications. Within the subgroup of patients taking OACs, international normalized ratio (INR) values were higher in those with lobar ICH as compared to those with deep ICH (2.8 ± 1.1 vs 2.2 ± 0.8; p = 0.011). The proportion of patients with lobar hematoma increased with increasing intensity of anticoagulation, with a ∼2-fold increased odds of lobar compared to deep ICH (odds 2.17; p = 0.03) in those exposed to overanticoagulation (INR values >3.0).
CONCLUSIONS:
OACs, as opposed to antiplatelets, predispose to lobar location of brain hematomas according to a dose-response relationship.openopenPezzini, A; Grassi, M; Paciaroni, M; Zini, A; Silvestrelli, G; Del Zotto, E; Caso, V; Dell'Acqua, Ml; Giossi, A; Volonghi, I; Simone, Am; Lanari, A; Costa, P; Poli, L; Morotti, A; De Giuli, V; Pepe, D; Gamba, M; Ciccone, A; Ritelli, M; Colombi, M; Agnelli, G; Padovani, APezzini, Alessandro; Grassi, M; Paciaroni, M; Zini, A; Silvestrelli, G; Del Zotto, E; Caso, V; Dell'Acqua, Ml; Giossi, A; Volonghi, I; Simone, Am; Lanari, A; Costa, P; Poli, L; Morotti, A; De Giuli, V; Pepe, D; Gamba, M; Ciccone, A; Ritelli, M; Colombi, Marina; Agnelli, G; Padovani, Alessandr
Measurement of the Branching Fraction for B- --> D0 K*-
We present a measurement of the branching fraction for the decay B- --> D0
K*- using a sample of approximately 86 million BBbar pairs collected by the
BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is
detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the
K*- through its decay to K0S pi-. We measure the branching fraction to be
B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid
Communications
Evidence for the Rare Decay B -> K*ll and Measurement of the B -> Kll Branching Fraction
We present evidence for the flavor-changing neutral current decay and a measurement of the branching fraction for the related
process , where is either an or
pair. These decays are highly suppressed in the Standard Model,
and they are sensitive to contributions from new particles in the intermediate
state. The data sample comprises
decays collected with the Babar detector at the PEP-II storage ring.
Averaging over isospin and lepton flavor, we obtain the branching
fractions and , where the
uncertainties are statistical and systematic, respectively. The significance of
the signal is over , while for it is .Comment: 7 pages, 2 postscript figues, submitted to Phys. Rev. Let
Measurement of the quasi-elastic axial vector mass in neutrino-oxygen interactions
The weak nucleon axial-vector form factor for quasi-elastic interactions is
determined using neutrino interaction data from the K2K Scintillating Fiber
detector in the neutrino beam at KEK. More than 12,000 events are analyzed, of
which half are charged-current quasi-elastic interactions nu-mu n to mu- p
occurring primarily in oxygen nuclei. We use a relativistic Fermi gas model for
oxygen and assume the form factor is approximately a dipole with one parameter,
the axial vector mass M_A, and fit to the shape of the distribution of the
square of the momentum transfer from the nucleon to the nucleus. Our best fit
result for M_A = 1.20 \pm 0.12 GeV. Furthermore, this analysis includes updated
vector form factors from recent electron scattering experiments and a
discussion of the effects of the nucleon momentum on the shape of the fitted
distributions.Comment: 14 pages, 10 figures, 6 table
A Study of Time-Dependent CP-Violating Asymmetries and Flavor Oscillations in Neutral B Decays at the Upsilon(4S)
We present a measurement of time-dependent CP-violating asymmetries in
neutral B meson decays collected with the BABAR detector at the PEP-II
asymmetric-energy B Factory at the Stanford Linear Accelerator Center. The data
sample consists of 29.7 recorded at the
resonance and 3.9 off-resonance. One of the neutral B mesons,
which are produced in pairs at the , is fully reconstructed in
the CP decay modes , , , () and , or in flavor-eigenstate
modes involving and (). The flavor of the other neutral B meson is tagged at the time of
its decay, mainly with the charge of identified leptons and kaons. The proper
time elapsed between the decays is determined by measuring the distance between
the decay vertices. A maximum-likelihood fit to this flavor eigenstate sample
finds . The value of the asymmetry amplitude is determined from
a simultaneous maximum-likelihood fit to the time-difference distribution of
the flavor-eigenstate sample and about 642 tagged decays in the
CP-eigenstate modes. We find , demonstrating that CP violation exists in the neutral B meson
system. (abridged)Comment: 58 pages, 35 figures, submitted to Physical Review
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