8,604 research outputs found
A Data Mining Perspective of XRF Elemental Analysis from Pueblo People’s Pottery
Hierarchical clustering was used to identify elemental signatures in artifacts attributed to the Pueblo peoples. The artifacts in this study are pottery samples found at different sites in the state of New Mexico, USA. Three methods were applied: complete, average, and Ward. Their corresponding cophenetic correlation coefficients were used to contrast the three methods. Elemental characterization was only based on X-ray fluorescence excitation from a portable spectrometer with the silver anode. The elemental correlations here disclosed by data mining techniques are expected to guide further archaeological studies and assist experts in the assessment of provenance and historical ethnographic studies.
XRF elemental analysi
Regulation of brain endothelial barrier function by microRNAs in health and neuroinflammation
Brain endothelial cells constitute the major cellular element of the highly specialized blood–brain barrier (BBB) and thereby contribute to CNS homeostasis by restricting entry of circulating leukocytes and blood-borne molecules into the CNS. Therefore, compromised function of brain endothelial cells has serious consequences for BBB integrity. This has been associated with early events in the pathogenesis of several disorders that affect the CNS, such as multiple sclerosis, HIV-associated neurologic disorder, and stroke. Recent studies demonstrate that brain endothelial microRNAs play critical roles in the regulation of BBB function under normal and neuroinflammatory conditions. This review will focus on emerging evidence that indicates that brain endothelial microRNAs regulate barrier function and orchestrate various phases of the neuroinflammatory response, including endothelial activation in response to cytokines as well as restoration of inflamed endothelium into a quiescent state. In particular, we discuss novel microRNA regulatory mechanisms and their contribution to cellular interactions at the neurovascular unit that influence the overall function of the BBB in health and during neuroinflammatio
Ultra Low-Power Analog Median Filters
The design and implementation of three analog median filter topologies, whose transistors operate in the deep weak-inversion region, is described. The first topology is a differential pairs array, in which drain currents are driven into two nodes in a differential fashion, while the second topology is based on a wide range OTA, which is used to maximize the dynamic range. Finally, the third topology uses three range-extended OTAs. The proposed weak-inversion filters were designed and fabricated in ON Semiconductor 0.5 micrometer technology through MOSIS. Experimental results of three-input fabricated prototypes for all three topologies are show, where power consumptions of 90nW in the first case, and 270nW in the other two cases can be noticed. A dual power supply +/-1.5 Volts were used
A low-voltage low-power front-end for wearable EEG systems
A low-voltage and low-power front-end for miniaturized, wearable EEG systems is presented. The instrumentation amplifier, which removes the electrode drift and conditions the signal for a 10-bit A/D converter, combines a chopping strategy with quasi-FGMOS (QFG) transistors to minimize low frequency noise whilst enabling operation at 1 V supply. QFG devices are also key to the A/D converter operating at 1.2 V with 70dB of SNR and an oversampling ratio of 64. The whole system consumes less than 2uW at 1.2V.Published versio
Reconstrucción de neoglande con colgajo uretral para el tratamiento quirúrgico de calcifilaxis peniana
ResumenIntroducciónLa arteriolopatía urémica calcificante, también conocida como calcifilaxis, es una entidad caracterizada por la presencia de áreas de necrosis isquémica junto con extensas calcificaciones de la capa media de las arteriolas de la piel; la etiopatogenia es compleja, las formas de presentación y evolución son diversas. La calcifilaxis del pene es una entidad muy rara. El dolor y la ulceración del glande es una de sus manifestaciones clínicas iniciales, el diagnóstico en estas etapas es difícil de establecer y el manejo debe ser integral. El tratamiento médico seguido del manejo quirúrgico se establecerá de acuerdo a la etapa y evolución de la enfermedad.La reconstrucción aislada del glande se recomienda tras una amputación traumática o quirúrgica por alguna enfermedad benigna o maligna. El objetivo es conseguir una apariencia estética razonable, permitir una micción fisiológica y tratar de conservar la mayor cantidad de tejido eréctil. En pacientes con calcifilaxis peniana, el manejo quirúrgico convencional es radical y consiste en falectomía parcial o total según sea el caso. El manejo conservador ha sido reportado mediante la desbridación de las lesiones ulcerosas en pene, tratamiento local y vigilancia.Caso clínicoSe presenta el caso de un paciente masculino de 59 años de edad con insuficiencia renal crónica en tratamiento con hemodiálisis, hospitalizado por cuadro de 5 días de evolución con úlcera dolorosa en glande, refractaria a manejo analgésico. Se realizó biopsia escisional de la lesión con estudio histopatológico confirmando calcifilaxis. Se plantea a paciente falectomía parcial la cual rechaza por lo que se ofrece reconstrucción en un tiempo como opción terapéutica.ConclusiónUtilizar injertos o colgajos de piel para realizar la reconstrucción del pene en pacientes con calcifilaxis no representa una opción viable. Por su gran aporte vascular, la uretra representa una buena opción de reconstrucción en pacientes con calcifilaxis en etapa inicial. La selección y evaluación de los pacientes debe ser muy cautelosa para que los resultados estéticos y funcionales sean aceptables.AbstractIntroductionCalcific uremic arteriolopathy, also known as calciphylaxis, is an entity characterized by areas of ischemic necrosis with extensive calcifications of the middle layer of the skin arterioles. Its etiopathogenesis is complex and its forms of presentation and progression are diverse. Calciphylaxis of the penis is an extremely rare entity. Pain and ulceration of the glans penis are initial clinical manifestations and diagnosis at these stages is difficult. Management should be comprehensive. Medical treatment, followed by surgical management, is established according to disease stage and progression.Isolated reconstruction of the glans penis is recommended when there is traumatic amputation or a surgical one due to benign or malignant disease. The goal is to obtain a reasonably esthetic appearance, to have physiologic micturition, and to spare the greatest amount of erectile tissue possible. Conventional surgical management in patients with penile calciphylaxis is radical and consists of partial or total phallectomy, depending on the case. Conservative management through ulcerous penile lesion debridement, local treatment, and surveillance has been reported.Case reportA 59-year-old man with chronic renal insufficiency in hemodialysis treatment was hospitalized for symptoms of 5-day progression of a painful ulcer on the glans penis that was refractory to analgesics. An excisional biopsy of the lesion was taken and the histopathologic study confirmed calciphylaxis. Partial phallectomy was suggested to the patient, but he rejected it, and so single stage reconstruction was offered as a therapeutic option.ConclusionThe use of skin grafts or flaps for penile reconstruction in patients with calciphylaxis is not a viable option. Because of its large blood supply, the urethra is a good reconstruction option in patients with initial-stage calciphylaxis. Patient selection and evaluation must be carried out with great care in order to have acceptable functional and esthetic results
Typing Supernova Remnants Using X-ray Line Emission Morphologies
We present a new observational method to type the explosions of young
supernova remnants (SNRs). By measuring the morphology of the Chandra X-ray
line emission in seventeen Galactic and Large Magellanic Cloud SNRs with a
multipole expansion analysis (using power ratios), we find that the
core-collapse SNRs are statistically more asymmetric than the Type Ia SNRs. We
show that the two classes of supernovae can be separated naturally using this
technique because X-ray line morphologies reflect the distinct explosion
mechanisms and structure of the circumstellar material. These findings are
consistent with recent spectropolarimetry results showing that core-collapse
SNe are intrinsically more asymmetric.Comment: 4 pages, 1 figure, accepted for publication in ApJ
Near-Infrared Polarimetric Adaptive Optics Observations of NGC 1068: A torus created by a hydromagnetic outflow wind
We present J' and K' imaging linear polarimetric adaptive optics observations
of NGC 1068 using MMT-Pol on the 6.5-m MMT. These observations allow us to
study the torus from a magnetohydrodynamical (MHD) framework. In a 0.5" (30 pc)
aperture at K', we find that polarisation arising from the passage of radiation
from the inner edge of the torus through magnetically aligned dust grains in
the clumps is the dominant polarisation mechanism, with an intrinsic
polarisation of 7.0%2.2%. This result yields a torus magnetic field
strength in the range of 482 mG through paramagnetic alignment, and
139 mG through the Chandrasekhar-Fermi method. The measured
position angle (P.A.) of polarisation at K is found to be similar to the
P.A. of the obscuring dusty component at few parsec scales using infrared
interferometric techniques. We show that the constant component of the magnetic
field is responsible for the alignment of the dust grains, and aligned with the
torus axis onto the plane of the sky. Adopting this magnetic field
configuration and the physical conditions of the clumps in the MHD outflow wind
model, we estimate a mass outflow rate 0.17 M yr at 0.4
pc from the central engine for those clumps showing near-infrared dichroism.
The models used were able to create the torus in a timescale of 10
yr with a rotational velocity of 1228 km s at 0.4 pc. We conclude
that the evolution, morphology and kinematics of the torus in NGC 1068 can be
explained within a MHD framework.Comment: 14 pages, 4 figures, Accepted by MNRA
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