1,174 research outputs found
EM Parametric Study of Length Matching Elements Exploiting an ANSYS HFSS Matlab-Python Driver
This work presents a Python-based driver for ANSYS HFSS for length matching elements (LME) implemented in Matlab. The driver allows full-wave EM parametric simulation of length matching elements, whose S-parameters are inserted in other circuit simulators, such as ADS, for a complete interconnect validation. Three different LME (i.e., trapezoidal, triangular, and rectangular) are analyzed using the driver in a common high-speed routing scenario. The driver proposed in this work allows verifying that the three LME considered have a similar performance up to 5 GHz, indicating that these LME can be used as mismatch (phase skew) compensation structures in some interfaces within this frequency band, such as USB 3.0, PCIe Gen3 or 1 GBASE Ethernet. On the other hand, the trapezoidal LME shows the best performance for frequencies higher than 5 GHz, with a low impact in the electromagnetic interference (EMI), making it the most recommended for high-speed interfaces with operating frequencies higher than 5 GHz
A Novel High-Performance Length Matching Element for High-Speed Interconnect Differential Channels
Length matching elements (LME) are used for intra-pair length matching and inter-pair skew reduction to get high data rates in high-speed differential channels. Although these structures are widely used in printed circuit boards (PCB), the effectiveness of the structure depends on its geometry and dimensions, allowing different design alternatives. In this work, a novel LME for PCB designs is proposed. It is formed by three sub-structures, such that the insertion and impedance profile can be parametrically controlled by the geometry of the proposed LME without affecting the length matching. Mixed-mode parameters, extracted from simulation data, shows that the proposed LME presents lower insertion loss and less electromagnetic interference (EMI), than trapezoidal LME. In addition, time domain reflected analysis (TDR) shows better impedance profile for the proposed LME than for the trapezoidal shape. Both frequency- and time-domain results indicate that the proposed LME can be a good alternative for length matching compensation in high-speed channels
Soil macroinvertebrates community and its temporal variation in a well-drained savannah of the Venezuelan Llanos
Morales-Márquez, Jimmy A., Hernández-Hernández, Rosa M., Sánchez, Gloria K., Lozano, Zenaida, Castro, Ignacio, Bravo, Carlos, Ramírez, Elizabeth and Jiménez Ballesta, Raimundo: "Soil macroinvertebrates community and its temporal variation in a well-drained savannah of the Venezuelan Llanos" published at European Journal of Soil Biology 84.2 (2018): 19-26; DOI: http://doi.org/10.1016/j.ejsobi.2017.11.002In the well-drained savannahs of Venezuelan Llanos, intensive agricultural activities could be causing damage to the soil, with negative consequences for the ecosystem. In order to avoid this problem, some agroecological alternatives are needed. Consequently, it is necessary to know the biologic dimension in this ecosystem, and within this, the soil macroinvertebrate community. The purpose of this work was to characterize this community in the natural savannah: its structure and diversity, its time variation and its relationship with the physical-chemical properties of the soil. A total of 72 samples were taken in different season along a period of time of 1405 days. The results revealed that the soil macrofauna had an average density of 243.5 ± 183.6 ind·m −2 , distributed in 32 families of 11 orders, with a diversity of N 1 = 4.5 ± 2.8 families. Coleoptera, Hymenoptera and Isoptera was the most dominants orders. The density, richness and diversity of families showed a temporal variation (r ≥ −0.5; p < 0,05). Additionally, the structure of the soil macroinvertebrate community showed a vertical variation. The relationship with soil properties differed according families: Lampyridae, Aphodiidae and Formicidae had a positive correlation with soil macro-porosity (radius of the pores > 15 μm); Tenthredinidae and Tenebrionidae had a positive correlation with the micro-porosity (pores ≤ 15 μm). The community in general, correlated positively with soil porosity and negatively with bulk density. This suggests that these soil properties need to be considered when designing agroecological technics in this area.We want to express our gratitude to the "Fondo Nacional para la Ciencia Innovación y Tecnología del Ministerio del Poder Popular para la Educación Universitaria, Ciencia y Tecnología", of the Boliviarian Republic of Venezuela, for the financial support of the project “Manejo Agroecológico de Suelos de Sabanas Bien Drenadas con Unidades de Producción Cereal-Ganado”, Nº G-2002000398, of which this study is part
p75NTR antagonists attenuate photoreceptor cell loss in murine models of retinitis pigmentosa
ProNGF signaling through p75NTR has been associated with neurodegenerative disorders. Retinitis pigmentosa (RP) comprises a group of inherited retinal dystrophies that causes progressive photoreceptor cell degeneration and death, at a rate dependent on the genetic mutation. There are more than 300 mutations causing RP, and this is a challenge to therapy. Our study was designed to explore a common mechanism for p75NTR in the progression of RP, and assess its potential value as a therapeutic target. The proNGF/p75NTR system is present in the dystrophic retina of the rd10 RP mouse model. Compared with wild-type (WT) retina, the levels of unprocessed proNGF were increased in the rd10 retina at early degenerative stages, before the peak of photoreceptor cell death. Conversely, processed NGF levels were similar in rd10 and WT retinas. ProNGF remained elevated throughout the period of photoreceptor cell loss, correlating with increased expression of α2-macroglobulin, an inhibitor of proNGF processing. The neuroprotective effect of blocking p75NTR was assessed in organotypic retinal cultures from rd10 and RhoP mouse models. Retinal explants treated with p75NTR antagonists showed significantly reduced photoreceptor cell death, as determined by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay and by preservation of the thickness of the outer nuclear layer (ONL), where photoreceptor nuclei are located. This effect was accompanied by decreased retinal-reactive gliosis and reduced TNFα secretion. Use of p75NTR antagonist THX-B (1,3-diisopropyl-1-[2-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-purin-7-yl)-acetyl]-urea) in vivo in the rd10 and RhoP mouse models, by a single intravitreal or subconjunctival injection, afforded neuroprotection to photoreceptor cells, with preservation of the ONL. This study demonstrates a role of the p75NTR/proNGF axis in the progression of RP, and validates these proteins as therapeutic targets in two different RP models, suggesting utility irrespective of etiology.Fil: Platón-Corchado, María. Consejo Superior de Investigaciones Científicas; EspañaFil: Barcelona, Pablo Federico. Mc Gill University. Lady Davis Research Intitute; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Jmaeff, Sean. Mc Gill University. Lady Davis Research Intitute; CanadáFil: Marchena, Miguel. Consejo Superior de Investigaciones Científicas; EspañaFil: Hernández-Pinto, Alberto M.. Consejo Superior de Investigaciones Científicas; EspañaFil: Hernández-Sánchez, Catalina. Consejo Superior de Investigaciones Científicas; EspañaFil: Saragovi, H. Uri. Mc Gill University. Lady Davis Research Intitute; CanadáFil: de la Rosa, Enrique J. Centro de Investigaciones Biológicas; Españ
Visual decline in aged mice is delayed by proinsulin
1 p.Visual decline is normally associated to the aging process.We search for cellular and molecular processes associated to normal aging. In addition, we have previously shown that human proinsulin (hPi) delays vision loss, as determined by electroretinography (ERG),and retinal degeneration, as determined by photoreceptor counting,in the rd10 mouse and the P23H rat models of Retinitis Pigmentosa.Our aim is to reveal additional potential benets of a hPi-based treatment in the aged retina.CONSOLIDER CSD2010-00045 SpainPeer reviewe
Cataract Surgery in Elderly Subjects with Heterozygous Familial Hypercholesterolemia in Prolonged Treatment with Statins
Background: Cataracts are the main cause of blindness and represent one fifth of visual problems worldwide. It is still unknown whether prolonged statin treatment favors the development of cataracts. We aimed to ascertain the prevalence of cataract surgery in elderly subjects with genetically diagnosed heterozygous familial hypercholesterolemia (HeFH) receiving statin treatment for ≥5 years, and compare this with controls. Methods: This is an observational, multicenter, case–control study from five lipid clinics in Spain. We collected data with the following inclusion criteria: age ≥65 years, LDL cholesterol levels ≥220 mg/dL without lipid-lowering drugs, a pathogenic mutation in a candidate gene for HeFH (LDLR, APOB, or PCSK9) and statin treatment for ≥5 years. Controls were selected from relatives of HeFH patients without hypercholesterolemia. Linear and logistic regressions based on generalized linear models and generalized estimating equations (GEE) were used. Cataract surgery was used as a proxy for cataract development. Results: We analyzed 205 subjects, 112 HeFH, and 93 controls, with a mean age of 71.8 (6.5) and 70.0 (7.3) years, respectively. HeFH subjects presented no difference in clinical characteristics, including smoking, hypertension, and type 2 diabetes mellitus, compared with controls. The mean duration of lipid-lowering treatment in HeFH was 22.5 (8.7) years. Cataract surgery prevalence was not significantly different between cases and controls. The presence of cataracts was associated neither with LDLc nor with the length of the statin therapy. Conclusion: In the present study, HeFH was not a risk factor for cataract surgery and prolonged statin treatment did not favor it either. These findings suggest that statin treatment is not related with cataracts
Proinsulin protects against age-related cognitive loss through anti-inflammatory convergent pathways
Brain inflammaging is increasingly considered as contributing to age-related cognitive loss and neurodegeneration. Despite intensive research in multiple models, no clinically effective pharmacological treatment has been found yet. Here, in the mouse model of brain senescence SAMP8, we tested the effects of proinsulin, a promising neuroprotective agent that was previously proven to be effective in mouse models of retinal neurodegeneration. Proinsulin is the precursor of the hormone insulin but also upholds developmental physiological effects, particularly as a survival factor for neural cells. Adeno-associated viral vectors of serotype 1 bearing the human proinsulin gene were administered intramuscularly to obtain a sustained release of proinsulin into the blood stream, which was able to reach the target area of the hippocampus. SAMP8 mice and the control strain SAMR1 were treated at 1 month of age. At 6 months, behavioral testing exhibited cognitive loss in SAMP8 mice treated with the null vector. Remarkably, the cognitive performance achieved in spatial and recognition tasks by SAMP8 mice treated with proinsulin was similar to that of SAMR1 mice. In the hippocampus, proinsulin induced the activation of neuroprotective pathways and the downstream signaling cascade, leading to the decrease of neuroinflammatory markers. Furthermore, the decrease of astrocyte reactivity was a central effect, as demonstrated in the connectome network of changes induced by proinsulin. Therefore, the neuroprotective effects of human proinsulin unveil a new pharmacological potential therapy in the fight against cognitive loss in the elderly.Postprint (published version
Comparative efficacy between atorvastatin and rosuvastatin in the prevention of cardiovascular disease recurrence
Background: There is no randomized clinical trials with recurrence of atherosclerotic cardiovascular disease (ASCVD) as a major outcome with rosuvastatin. In order to analyze potential differences in the clinical response to atorvastatin and rosuvastatin in secondary ASCVD prevention, we have analyzed the clinical evolution of those subjects of the Dyslipemia Registry of the Spanish Society of Arteriosclerosis (SEA) who at the time of inclusion in the Registry had already suffered an ASCVD. Methods: This observational, retrospective, multicenter, national study was designed to determine potential differences between the use of atorvastatin and rosuvastatin in the ASCVD recurrence. Three different follow-up start-times were performed: time of inclusion in the registry; time of first event if this occurred after 2005, and time of first event without date restriction. Results: Baseline characteristics were similar between treatment groups. Among atorvastatin or rosuvastatin users, 89 recurrences of ASCVD were recorded (21.9%), of which 85.4% were coronary. At the inclusion of the subject in the registry, 345 participants had not suffered a recurrence yet. These 345 subjects accumulated 1050 person-years in a mean follow-up of 3 years. Event rates were 2.73 (95% CI: 1.63, 4.25) cases/100 person-years and 2.34 (95% CI: 1.17, 4.10) cases/100 person-years in the atorvastatin and rosuvastatin groups, respectively. There were no statistically significant differences between the two groups independently of the follow-up start-time. Conclusions: This study does not find differences between high doses of rosuvastatin and atorvastatin in the recurrence of ASCVD, and supports their use as clinically equivalent in secondary prevention of ASCVD
In Utero p,p′-DDE Exposure and Infant Neurodevelopment: A Perinatal Cohort in Mexico
BACKGROUND: Evidence suggests that p,p′-dichlorodiphenyldichloroethene (DDE) affects neurodevelopment in infants, although a critical exposure window has not yet been identified. OBJECTIVES: Our goal was to assess the prenatal DDE exposure window and its effect on the psychomotor development index (PDI) and mental development index (MDI) during the first year of life. METHODS: We recruited 244 children whose pregnancies and deliveries were uncomplicated, and whose mothers were monitored throughout the pregnancy. Participating mothers were not occupationally exposed to DDT (dichlorodiphenyltrichloroethane) but were residents of a zone in Mexico with endemic malaria. We measured serum levels of DDE before pregnancy and during each trimester of the pregnancy. We evaluated PDI and MDI of the Bayley Scales for Infant Development (BSID-II), at 1, 3, 6, and 12 months of age. We adjusted for quality of the home environment and maternal intellectual coefficient (IQ). We used generalized mixed-effects models for statistical analysis. RESULTS: Third-trimester DDE level (7.8 ± 2.8 ppb) was significantly higher than the level at baseline, first, and second trimesters, but the differences never exceeded 20%. Only DDE levels during the first trimester of pregnancy were associated with a significant reduction in PDI (every doubled increase of DDE level reduced the PDI 0.5 points). DDE was not associated with MDI. CONCLUSIONS: A critical window of exposure to DDE in utero may be the first trimester of the pregnancy, and psychomotor development is a target of this compound. Residues of DDT metabolites may present a risk of developmental delay for years after termination of DDT use
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