104 research outputs found

    Low Cost Timing System for High Precision Particle Detection

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    The project goal was to find a way to make a low-cost high precision timing system. High precision timing systems are already on the market, however, at a high cost. Various particle research projects need a large number of timers, so a substantial budget is required. In order to bypass the need for a large enough budget, commercially available parts were used and tested. The timing system consisted of multiple parts with different low-cost microchips and counters. In order for the project to meet its goal, the timers need to work under 50 picoseconds. Although some tests showed the timers working under 50 picoseconds, most tests were over. Additional testing and research need to be done to improve on the work that was done

    Blooming plant species diversity patterns in two adjacent Costa Rican highland ecosystems

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    The Costa Rican Paramo is a unique ecosystem with high levels of endemism that is geographically isolated from the Andean Paramos. Paramo ecosystems occur above Montane Forests, below the permanent snow level, and their vegetation notably differs from that of adjacent Montane Forests. We compared the composition and beta diversity of blooming plant species using phenological data from functional plant groups (i.e., insect-visited, bird-visited and insect+bird-visited plants) between a Paramo and a Montane Forest site in Costa Rica and analyzed seasonal changes in blooming plant diversity between the rainy and dry seasons. Species richness was higher in the Montane Forest for all plant categories, except for insect- 32 visited plants, which was higher in the Paramo. Beta diversity and blooming plant composition differed between both ecosystems and seasons. Differences in species richness and beta diversity between Paramo and the adjacent Montane Forest are likely the result of dispersal events that occurred during the last glacial period and subsequent isolation, as climate turned to tropical conditions after the Pleistocene, and to stressful abiotic conditions in the Paramo ecosystem that limits species establishment. Differences in blooming plant composition between both ecosystems and seasons are likely attributed to differential effects of climatic cues triggering the flowering events in each ecosystem, but phylogenetic conservatism cannot be discarded. Analyzes of species composition and richness based on flowering phenology data are useful to evaluate potential floral resources for floral visitors (insects and birds) and how these resources change spatially and temporarily in endangered ecosystems such as the Paramo.Ministerio de Ciencia y Tecnología/[FI-040B-19]/MICIT-CONICYT/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de BiologíaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biodiversidad y Ecología Tropical (CIBET

    TRAIL receptors promote constitutive and inducible IL-8 secretion in non-small cell lung carcinoma

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    Interleukin-8 (IL-8/CXCL8) is a pro-angiogenic and pro-inflammatory chemokine that plays a role in cancer development. Non-small cell lung carcinoma (NSCLC) produces high amounts of IL-8, which is associated with poor prognosis and resistance to chemo-radio and immunotherapy. However, the signaling pathways that lead to IL-8 production in NSCLC are unresolved. Here, we show that expression and release of IL-8 are regulated autonomously by TRAIL death receptors in several squamous and adenocarcinoma NSCLC cell lines. NSCLC constitutively secrete IL-8, which could be further enhanced by glucose withdrawal or by treatment with TRAIL or TNF alpha. In A549 cells, constitutive and inducible IL-8 production was dependent on NF-kappa B and MEK/ERK MAP Kinases. DR4 and DR5, known regulators of these signaling pathways, participated in constitutive and glucose deprivation-induced IL-8 secretion. These receptors were mainly located intracellularly. While DR4 signaled through the NF-kappa B pathway, DR4 and DR5 both regulated the ERK-MAPK and Akt pathways. FADD, caspase-8, RIPK1, and TRADD also regulated IL-8. Analysis of mRNA expression data from patients indicated that IL-8 transcripts correlated with TRAIL, DR4, and DR5 expression levels. Furthermore, TRAIL receptor expression levels also correlated with markers of angiogenesis and neutrophil infiltration in lung squamous carcinoma and adenocarcinoma. Collectively, these data suggest that TRAIL receptor signaling contributes to a pro-tumorigenic inflammatory signature associated with NSCLC

    Modeling of autosomal-dominant retinitis pigmentosa in Caenorhabditis elegans uncovers a nexus between global impaired functioning of certain splicing factors and cell type-specific apoptosis

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    Retinitis pigmentosa (RP) is a rare genetic disease that causes gradual blindness through retinal degeneration. Intriguingly, seven of the 24 genes identified as responsible for the autosomal-dominant form (adRP) are ubiquitous spliceosome components whose impairment causes disease only in the retina. The fact that these proteins are essential in all organisms hampers genetic, genomic, and physiological studies, but we addressed these difficulties by using RNAi in Caenorhabditis elegans. Our study of worm phenotypes produced by RNAi of splicing-related adRP (s-adRP) genes functionally distinguishes between components of U4 and U5 snRNP complexes, because knockdown of U5 proteins produces a stronger phenotype. RNA-seq analyses of worms where s-adRP genes were partially inactivated by RNAi, revealed mild intron retention in developing animals but not in adults, suggesting a positive correlation between intron retention and transcriptional activity. interestingly, RNAi of s-adRP genes produces an increase in the expression of atl-1 (homolog of human ATR), which is normally activated in response to replicative stress and certain DNA-damaging agents. The up-regulation of atl-1 correlates with the ectopic expression of the pro-apoptotic gene egl-1 and apoptosis in hypodermal cells, which produce the cuticle, but not in other cell types. Our model in C. elegans resembles s-adRP in two aspects: The phenotype caused by global knockdown of s-adRP genes is cell type-specific and associated with high transcriptional activity. Finally, along with a reduced production of mature transcripts, we propose a model in which the retina-specific cell death in s-adRP patients can be induced through genomic instability

    A neurodegenerative disease landscape of rare mutations in Colombia due to founder effects

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    Background The Colombian population, as well as those in other Latin American regions, arose from a recent tri-continental admixture among Native Americans, Spanish invaders, and enslaved Africans, all of whom passed through a population bottleneck due to widespread infectious diseases that left small isolated local settlements. As a result, the current population reflects multiple founder effects derived from diverse ancestries. Methods We characterized the role of admixture and founder effects on the origination of the mutational landscape that led to neurodegenerative disorders under these historical circumstances. Genomes from 900 Colombian individuals with Alzheimer’s disease (AD) [n = 376], frontotemporal lobar degeneration-motor neuron disease continuum (FTLD-MND) [n = 197], early-onset dementia not otherwise specified (EOD) [n = 73], and healthy participants [n = 254] were analyzed. We examined their global and local ancestry proportions and screened this cohort for deleterious variants in disease-causing and risk-conferring genes. Results We identified 21 pathogenic variants in AD-FTLD related genes, and PSEN1 harbored the majority (11 pathogenic variants). Variants were identified from all three continental ancestries. TREM2 heterozygous and homozygous variants were the most common among AD risk genes (102 carriers), a point of interest because the disease risk conferred by these variants differed according to ancestry. Several gene variants that have a known association with MND in European populations had FTLD phenotypes on a Native American haplotype. Consistent with founder effects, identity by descent among carriers of the same variant was frequent. Conclusions Colombian demography with multiple mini-bottlenecks probably enhanced the detection of founder events and left a proportionally higher frequency of rare variants derived from the ancestral populations. These findings demonstrate the role of genomically defined ancestry in phenotypic disease expression, a phenotypic range of different rare mutations in the same gene, and further emphasize the importance of inclusiveness in genetic studies.Q2Q2Antecedentes La población colombiana, así como la de otras regiones latinoamericanas, surgió de una mezcla tricontinental reciente entre los nativos americanos, los invasores españoles y los africanos esclavizados, todos los cuales pasaron por un cuello de botella poblacional debido a enfermedades infecciosas generalizadas que dejaron a pequeños aislados. asentamientos locales. Como resultado, la población actual refleja múltiples efectos fundadores derivados de diversas ascendencias. Métodos Caracterizamos el papel de la mezcla y los efectos fundadores en el origen del paisaje mutacional que condujo a trastornos neurodegenerativos en estas circunstancias históricas. Genomas de 900 individuos colombianos con enfermedad de Alzheimer (EA) [n = 376], continuo degeneración lobar frontotemporal-enfermedad de la motoneurona (FTLD-MND) [n = 197], demencia de inicio temprano no especificada (EOD) [n = 73 ], y participantes sanos [n = 254] fueron analizados. Examinamos sus proporciones de ascendencia global y local y examinamos esta cohorte en busca de variantes nocivas en los genes que causan enfermedades y confieren riesgos. Resultados Identificamos 21 variantes patogénicas en genes relacionados con AD-FTLD, y PSEN1 albergaba la mayoría (11 variantes patogénicas). Se identificaron variantes de las tres ascendencias continentales. Las variantes heterocigotas y homocigotas de TREM2 fueron las más comunes entre los genes de riesgo de EA (102 portadores), un punto de interés porque el riesgo de enfermedad conferido por estas variantes difería según la ascendencia. Varias variantes genéticas que tienen una asociación conocida con MND en poblaciones europeas tenían fenotipos FTLD en un haplotipo nativo americano. De acuerdo con los efectos del fundador, la identidad por descendencia entre portadores de la misma variante fue frecuente. Conclusiones La demografía colombiana con múltiples mini-cuellos de botella probablemente mejoró la detección de eventos fundadores y dejó una frecuencia proporcionalmente más alta de variantes raras derivadas de las poblaciones ancestrales. Estos hallazgos demuestran el papel de la ascendencia definida genómicamente en la expresión fenotípica de la enfermedad, un rango fenotípico de diferentes mutaciones raras en el mismo gen, y enfatizan aún más la importancia de la inclusión en los estudios genéticos.https://orcid.org/0000-0001-6529-7077https://scholar.google.com/citations?hl=es&user=kaGongoAAAAJ&view_op=list_works&sortby=pubdatehttps://scienti.minciencias.gov.co/cvlac/visualizador/generarCurriculoCv.do?cod_rh=0000055000&lang=esRevista Internacional - Indexad

    A neurodegenerative disease landscape of rare mutations in Colombia due to founder effects.

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    Background: The Colombian population, as well as those in other Latin American regions, arose from a recent tri-continental admixture among Native Americans, Spanish invaders, and enslaved Africans, all of whom passed through a population bottleneck due to widespread infectious diseases that left small isolated local settlements. As a result, the current population reflects multiple founder effects derived from diverse ancestries. Methods: We characterized the role of admixture and founder effects on the origination of the mutational landscape that led to neurodegenerative disorders under these historical circumstances. Genomes from 900 Colombian individuals with Alzheimer's disease (AD) [n = 376], frontotemporal lobar degeneration-motor neuron disease continuum (FTLD-MND) [n = 197], early-onset dementia not otherwise specified (EOD) [n = 73], and healthy participants [n = 254] were analyzed. We examined their global and local ancestry proportions and screened this cohort for deleterious variants in disease-causing and risk-conferring genes. Results: We identified 21 pathogenic variants in AD-FTLD related genes, and PSEN1 harbored the majority (11 pathogenic variants). Variants were identified from all three continental ancestries. TREM2 heterozygous and homozygous variants were the most common among AD risk genes (102 carriers), a point of interest because the disease risk conferred by these variants differed according to ancestry. Several gene variants that have a known association with MND in European populations had FTLD phenotypes on a Native American haplotype. Consistent with founder effects, identity by descent among carriers of the same variant was frequent. Conclusions: Colombian demography with multiple mini-bottlenecks probably enhanced the detection of founder events and left a proportionally higher frequency of rare variants derived from the ancestral populations. These findings demonstrate the role of genomically defined ancestry in phenotypic disease expression, a phenotypic range of different rare mutations in the same gene, and further emphasize the importance of inclusiveness in genetic studies

    Variability and magnitude of brain glutamate levels in schizophrenia: a meta and mega-analysis

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    Glutamatergic dysfunction is implicated in schizophrenia pathoaetiology, but this may vary in extent between patients. It is unclear whether inter-individual variability in glutamate is greater in schizophrenia than the general population. We conducted meta-analyses to assess (1) variability of glutamate measures in patients relative to controls (log coefficient of variation ratio: CVR); (2) standardised mean differences (SMD) using Hedges g; (3) modal distribution of individual-level glutamate data (Hartigan’s unimodality dip test). MEDLINE and EMBASE databases were searched from inception to September 2022 for proton magnetic resonance spectroscopy (1H-MRS) studies reporting glutamate, glutamine or Glx in schizophrenia. 123 studies reporting on 8256 patients and 7532 controls were included. Compared with controls, patients demonstrated greater variability in glutamatergic metabolites in the medial frontal cortex (MFC, glutamate: CVR = 0.15, p < 0.001; glutamine: CVR = 0.15, p = 0.003; Glx: CVR = 0.11, p = 0.002), dorsolateral prefrontal cortex (glutamine: CVR = 0.14, p = 0.05; Glx: CVR = 0.25, p < 0.001) and thalamus (glutamate: CVR = 0.16, p = 0.008; Glx: CVR = 0.19, p = 0.008). Studies in younger, more symptomatic patients were associated with greater variability in the basal ganglia (BG glutamate with age: z = −0.03, p = 0.003, symptoms: z = 0.007, p = 0.02) and temporal lobe (glutamate with age: z = −0.03, p = 0.02), while studies with older, more symptomatic patients associated with greater variability in MFC (glutamate with age: z = 0.01, p = 0.02, glutamine with symptoms: z = 0.01, p = 0.02). For individual patient data, most studies showed a unimodal distribution of glutamatergic metabolites. Meta-analysis of mean differences found lower MFC glutamate (g = −0.15, p = 0.03), higher thalamic glutamine (g = 0.53, p < 0.001) and higher BG Glx in patients relative to controls (g = 0.28, p < 0.001). Proportion of males was negatively associated with MFC glutamate (z = −0.02, p < 0.001) and frontal white matter Glx (z = −0.03, p = 0.02) in patients relative to controls. Patient PANSS total score was positively associated with glutamate SMD in BG (z = 0.01, p = 0.01) and temporal lobe (z = 0.05, p = 0.008). Further research into the mechanisms underlying greater glutamatergic metabolite variability in schizophrenia and their clinical consequences may inform the identification of patient subgroups for future treatment strategies
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