50 research outputs found
Noise Cancellation using Selectable Adaptive Algorithm for Speech in Variable Noise Environment
Some of the teething problems associated in the use of two-sensor noise cancellation systems are the nature of the noise signals—a problem that imposes the use of highly complex algorithms in reducing the noise. The usage of such methods can be impractical for many real time applications, where speed of convergence and processing time are critical. At the same time, the existing approaches are based on using a single, often complex adaptive filter to minimize noise, which has been determined to be inadequate and ineffective. In this paper, a new mechanism is proposed to reduce background noise from speech communications. The procedure is based on a two-sensor adaptive noise canceller that is capable of assigning an appropriate filter adapting to properties of the noise. The criterion to achieve this is based on measuring the eigenvalue spread based on the autocorrelation of the input noise. The proposed noise canceller (INC) applies an adaptive algorithm according to the characteristics of the input signal. Various experiments based on this technique using real-world signals are conducted to gauge the effectiveness of the approach. Initial results illustrated the system capabilities in executing noise cancellation under different types of environmental noise. The results based on the INC technique indicate fast convergence rates; improvements up to 30 dB in signal-to-noise ratio and at the same time shows 65% reduction of computational power compared to conventional method
Impaired Phagocytosis in Localized Aggressive Periodontitis: Rescue by Resolvin E1
Resolution of inflammation is an active temporally orchestrated process demonstrated by the biosynthesis of novel proresolving mediators. Dysregulation of resolution pathways may underlie prevalent human inflammatory diseases such as cardiovascular diseases and periodontitis. Localized Aggressive Periodontitis (LAP) is an early onset, rapidly progressing form of inflammatory periodontal disease. Here, we report increased surface P-selectin on circulating LAP platelets, and elevated integrin (CD18) surface expression on neutrophils and monocytes compared to healthy, asymptomatic controls. Significantly more platelet-neutrophil and platelet-monocyte aggregates were identified in circulating whole blood of LAP patients compared with asymptomatic controls. LAP whole blood generates increased pro-inflammatory LTB4 with addition of divalent cation ionophore A23187 (5 µM) and significantly less, 15-HETE, 12-HETE, 14-HDHA, and lipoxin A4. Macrophages from LAP subjects exhibit reduced phagocytosis. The pro-resolving lipid mediator, Resolvin E1 (0.1–100 nM), rescues the impaired phagocytic activity in LAP macrophages. These abnormalities suggest compromised resolution pathways, which may contribute to persistent inflammation resulting in establishment of a chronic inflammatory lesion and periodontal disease progression
Plasma Apolipoprotein Levels Are Associated with Cognitive Status and Decline in a Community Cohort of Older Individuals
<div><h3>Objectives</h3><p>Apolipoproteins have recently been implicated in the etiology of Alzheimer’s disease (AD). In particular, Apolipoprotein J (ApoJ or clusterin) has been proposed as a biomarker of the disease at the pre-dementia stage. We examined a group of apolipoproteins, including ApoA1, ApoA2, ApoB, ApoC3, ApoE, ApoH and ApoJ, in the plasma of a longitudinal community based cohort.</p> <h3>Methods</h3><p>664 subjects (257 with Mild Cognitive Impairment [MCI] and 407 with normal cognition), mean age 78 years, from the Sydney Memory and Aging Study (MAS) were followed up over two years. Plasma apolipoprotein levels at baseline (Wave 1) were measured using a multiplex bead fluorescence immunoassay technique.</p> <h3>Results</h3><p>At Wave 1, MCI subjects had lower levels of ApoA1, ApoA2 and ApoH, and higher levels of ApoE and ApoJ, and a higher ApoB/ApoA1 ratio. Carriers of the apolipoprotein E ε4 allele had significantly lower levels of plasma ApoE, ApoC3 and ApoH and a significantly higher level of ApoB. Global cognitive scores were correlated positively with ApoH and negatively with ApoJ levels. ApoJ and ApoE levels were correlated negatively with grey matter volume and positively with cerebrospinal fluid (CSF) volume on MRI. Lower ApoA1, ApoA2 and ApoH levels, and higher ApoB/ApoA1 ratio, increased the risk of cognitive decline over two years in cognitively normal individuals. ApoA1 was the most significant predictor of decline. These associations remained after statistically controlling for lipid profile. Higher ApoJ levels predicted white matter atrophy over two years.</p> <h3>Conclusions</h3><p>Elderly individuals with MCI have abnormal apolipoprotein levels, which are related to cognitive function and volumetric MRI measures cross-sectionally and are predictive of cognitive impairment in cognitively normal subjects. ApoA1, ApoH and ApoJ are potential plasma biomarkers of cognitive decline in non-demented elderly individuals.</p> </div
Extended fast fixed order RLS adaptive filters
The existing derivations of conventional fast RLS adaptive filters are intrinsically dependent on the shift structure in the input regression vectors. This structure arises when a tapped-delay line (FIR) filter is used as a modeling filter. We show, unlike what original derivations may suggest, that fast fixed-order RLS adaptive algorithms are not limited to FIR filter structures. We show that fast recursions in both explicit and array forms exist for more general data structures, such as orthonormally based models. One of the benefits of working with orthonormal bases is that fewer parameters can be used to model long impulse responses
Roles of equalization in radar imaging: modeling for superesolution in 3D reconstruction
Cardiac parasyimpathetic innervation and the apical left ventricular aneurysms of Chagas' heart disease
Editorial. Politica y Salud.Aniyar de Castro, LolitaLa inervación parasimpática cardíaca y su posible relación con el aneurisma apical ventricular izquierdo de los pacientes con Enfermedad de ChagasCardiac parasyimpathetic innervation and the apical left ventricular aneurysms of Chagas' heart disease.Dávila S., Diego F.Donis, José H.Torres M., ArgenisNavas, MaríaArata de Bellabarba, GabrielaVásquez, Carlos J.Figueroa, OrlandoNavarro, AlexisAmro, MarcialFaoddul; MerchedRossel R., OsmánGottberg, Carlos F.González G., José C.Correlación clínico-radiológica pulmonar en obreros de una fábrica de calPulmonary radiological clinical correlation in a lime factory workers.Calderón de Cabrera, LourdesCésaro de Castris, ElioSexualidad humana y causas de disfunciones sexualesHuman Sexuality and Sexual Dysfunction's Causes.Pérez Feo, MirnaRelación entre estado nutricional y características socioeconómicas en pre-escolares, Mérida, VenezuelaRelationship between nutritional status and socioeconomic characteristics in pre-school children, Mérida, VenezuelaHernández, MoreliaSalinas, Pedro JoséCambios motivacionales en pacientes afectados por infarto al miocardioMotivational changes in inpacients affected by a heart attack.Esqueda Torres, LuisMultivariate analysis to discriminate species of phlebotomine sandflies (Diptera:Psychodidae). Lutzomyia cayennensis and Lutzomyia yencanensisAnálisis multivariante para discriminar especies de flebotominos(Diptera:Psychodidae). Lutzomyia cayennensis y Lutzomyia yencanensisCazorla, DalmiroAñez, NéstorMárquez, VíctorNieves, ElsaAlteraciones enzimáticas séricas en la hipervitaminosis K3 agudaSerum enzimatic alterations in the acute K3 hypervitaminosisVillavicencio M.,A.J.Somoza T., C.J.Tauil B.,E.Alarcón C.,O.M.Revisión de librosSalinas, Pedro JoséSemblanza. Dr. Eduardo Jorge Briese SerghieEscalante, [email protected]@[email protected]@intercable.net.veNivel analíticosemestra
Algorithm for dealing with time‐varying signal within sliding‐window for harmonics estimation
Frequency-domain subcarrier diversity receiver for discrete Hartley transform OFDM systems
Soluble amyloid precursor protein (APP) regulates transthyretin and Klotho gene expression without rescuing the essential function of APP
Amyloidogenic processing of the amyloid precursor protein (APP) generates a large secreted ectodomain fragment (APPsβ), β-amyloid (Aβ) peptides, and an APP intracellular domain (AICD). Whereas Aβ is viewed as critical for Alzheimer's disease pathogenesis, the role of other APP processing products remains enigmatic. Of interest, the AICD has been implicated in transcriptional regulation, and N-terminal cleavage of APPsβ has been suggested to produce an active fragment that may mediate axonal pruning and neuronal cell death. We previously reported that mice deficient in APP and APP-like protein 2 (APLP2) exhibit early postnatal lethality and neuromuscular synapse defects, whereas mice with neuronal conditional deletion of APP and APLP2 are viable. Using transcriptional profiling, we now identify transthyretin (TTR) and Klotho as APP/APLP2-dependent genes whose expression is decreased in loss-of-function states but increased in gain-of-function states. Significantly, by creating an APP knockin allele that expresses only APPsβ protein, we demonstrate that APPsβ is not normally cleaved in vivo and is fully capable of mediating the APP-dependent regulation of TTR and Klotho gene expression. Despite being an active regulator of gene expression, APPsβ did not rescue the lethality and neuromuscular synapse defects of APP and APLP2 double-KO animals. Our studies identify TTR and Klotho as physiological targets of APP that are regulated by soluble APPsβ independent of developmental APP functions. This unexpected APP-mediated signaling pathway may play an important role in maintaining TTR and Klotho levels and their respective functions in Aβ sequestration and aging