212 research outputs found
Involvement of Free Radicals in the Development and Progression of Alzheimer’s Disease
Alzheimer’s disease (AD) is a major dementia related to an overproduction of free radicals (FRs), which leads to the generation of oxidative stress in brain tissue. Amyloid beta-peptide of 42 amino acid residues (Aβ1–42) is the main source of FRs in patients with AD. βA1–42 results from hydrolysis of the amyloid precursor protein by β-secretase in a process known as the amyloidogenic pathway. During βA1–42 aggregation, the peptide interacts with various transition metals to produce hydrogen peroxide (H2O2) by the Fenton reaction, generating the hydroxyl radical (•OH), which damages lipids, proteins, and nucleic acids, thereby contributing to neurodegeneration. In addition, βA1–42 is recognized by microglial receptors; it activates these cells, causing overproduction of superoxide anion (O2•−) by NADPH oxidase; O2•− is also converted into H2O2 and finally to •OH in the Fenton reaction. Other factors that contribute to oxidative stress during microglial activation are the overproduction of nitric oxide and interleukins and the overexpression of some enzymes, including cyclooxygenase and inducible nitric oxide synthase, all of which contribute to FR production. Currently, various models in vitro and in vivo exist that permit quantification of O2•− and H2O2 and determination of the effects of these reactive oxygen species
Riqueza y Diversidad Florística de un Bosque de Niebla Subandino en la Reserva Forestal Laguna de Pedro Palo (Tena – Cundinamarca, Colombia)
La Reserva Forestal Laguna de Pedro Palo (RFLPP) está situada en la vertiente occidental de la Cordillera Oriental colombiana, en la zona de vida subandina. Tradicionalmente esta región ha soportado uso agropecuario y explotación forestal, que ha reducido la cobertura vegetal original a relictos de bosque ubicados especialmente cerca de las fuentes de agua, y actualmente protegidos en la Reserva Forestal Protectora Productora (RFPP). El objetivo principal de este estudio fue contribuir al conocimiento de la flora de este bosque. En un área de 0.12 ha., se registró un total de 2462 individuos, representados en 71 familias, 117 géneros y 204 especies, de las cuales 21 se encuentran en alguna categoría de amenaza. Además el bosque presenta altos valores de diversidad (H’: 2.21 – 3.20) y bajos de dominancia (d: 0,13 y 0,37), lo cual indica que esta región debe considerarse prioritaria en planes de conservación. El análisis fitogeográfico comparativo demuestra que el 83,12% de los géneros identificados son de origen tropical y el 40,26% de origen pantropical. El bosque presenta composición heterogénea: un bosque mixto de lauráceas y un bosque de roble, además de elementos de bosque subandino y andino en importante proporción, constituyéndolo en ecotono entre estas regiones de vida
Atypical Lemierre’s syndrome caused by Prevotella oris
Lemierre’s syndrome is a rare form of severe sepsis secondary to oropharyngeal infection characterized by septic thrombophlebitis of the internal jugular vein with disseminated infections, with the lungs being the most frequent target. We report the case of a previously
healthy 15-year-old admitted to the intensive care unit because of septic shock, brain and lung abscesses, and a positive blood culture for Prevotella oris with a clinical presentation compatible with the diagnosis of Lemierre’s syndrome. Conclusion: This is an atypical presentation of Lemierre’s syndrome because of the isolated microorganism
Consultoría integral en una empresa comercializadora de ferretería para lograr estructurar y formalizar los procesos de la empresa para una mejor gestión y desarrollo, en el municipio de Tlaquepaque, Jalisco
Continuación del proyecto iniciado en el período de primavera 2022, el equipo de consultores participa en una empresa dedicada a compraventa de insumos ferreteros fundada hace 25 años, con la experiencia adquirida por sus fundadores previamente al trabajar en un negocio familiar del mismo giro. La gestión de la empresa se realiza de forma empírica y poco formal, ofrecen a sus clientes las marcas más importantes del mercado, siendo distribuidores directos de estas, cumpliendo con calidad, precio y servicio. Su mercado está identificado en: Industrias, Ferreterías al mayoreo y Ferreterías al menudeo a quienes venden 95% a crédito y 5% de contado en ZMG y varios estados de la república. Cuentan con un equipo de ventas que realiza esfuerzos importantes para generar ingresos, pero la situación de desabasto de insumos de sus proveedores a raíz del COVID impide que los pedidos a sus clientes se surtan en tiempo y forma. Así mismo esto genera un problema en el almacén respecto a las entradas y salidas, contando con un espacio insuficiente y productos obsoletos o de lento movimiento. Las instalaciones físicas de la organización son limitadas.Su situación financiera es un área de oportunidad, ya que es conocida de forma parcial. Durante el período de verano 2022 se brinda seguimiento a las propuestas realizadas en el periodo anterior y se procede a revisar las situaciones y problemas que presenta la organización de acuerdo al avance actualizando el diagnóstico por medio de un Roadmap, revisando su modelo de negocios a través de CANVAS, realizando nuevas propuestas para mejorar la empresa en el contexto y situación actual.ITESO, A.C
BRUCELOSIS HUMANA EN ESTUDIANTES DE LA ESCUELA DE BIOANÁLISIS, UNIVERSIDAD DE LOS ANDES-VENEZUELA
La brucelosis genera grandes pérdidas económicas tanto al productor como al país; produciendo graves problemas de salud pública ocasionados por el descuido en el control de la vacunación animal y medidas preventivas al hombre. En la Escuela de Bioánalisis de la Universidad de los Andes la gran mayoría de sus estudiantes provienen de zonas endémicas para la brucelosis como lo son: Santa Barbára del Zulia y El Vigia. Razón que nos motivó a realizar el presente estudio de investigación. Un total de 204 (29.9%) de los estudiantes se les aplicó una encuesta epidemiológica. Luego se les tomo 6 ml de sangre venosa para obtener el suero sanguíneo y ser analizados mediante las técnicas de Rosa de Bengala, la Microaglutinación en placa con fenol con 2-Mercaptoetanol. De esta manera conocer el porcentaje de seropositividad de dicha población estudiantil. Los resultados arrojados indicaron que 3 (1.47%) de los estudiantes fueron seropositivos y 203 (98.5%) seronegativos a los antígenos anti-Brucella sp. Lo que demuestra que en la Escuela de Bioánalisis existe la enfermedad. Abstract Brucellosis causes economic losses both to the producer and the country, producing serious piblic health problems due to the lack of control on animal vaccination and preventive measures to individuals. At the School of Bionalysis at the University of Los Antes, most of the students come from endemic regions to Brucellosis, such as: Santa Barbára del Zulia and El Vigia. This sitiation encouraged us to perform this research. 204 (29.9%) of the students were given a serological survey. Then, 6 ml of blood were drawn to obtain the blood serum and to be analyzed by the Rose Bengal technique, the Microagglutination on the a plate with phenol and 2mercapethanol. At his way could know the seropositive percentage of such student group. The results showed that 3 (1.47%) of the students were seropositive and 203 (98.5%) were seronegative to antigens like anti-Brucella sp. This proves that the disease exists at the School of Bionalysis. Palabras claves: Brucella, zoonosis, humanos, epidemiología, diagnóstico serólogic
Evolution of the gulf of Cadiz margin and southwest Portugal contourite depositional system : Tectonic, sedimentary and paleoceanographic implications from IODP expedition 339
Acknowledgments This research used samples and data collected through the Integrated Ocean Drilling Program (IODP). The research was partially supported through the CTM 2008-06399-C04/MAR, CTM 2012-39599-C03, CGL2011-26493, CTM2012-38248, SA263U14, IGCP-619, INQUA 1204 and FWF P25831-N29 Projects. Some data were collected with 94-1090-C03-03 (FADO) and MAR-98-0209 (TASYO) Projects. Research was conducted in the framework of the Continental Margins Research Group of the Royal Holloway University of London, People and the Program (Marie Curie Actions) of the European Union's Seventh Framework Program FP7/2007-2013/ under REA Grant Agreement No. 290201 MEDGATE’. We are very grateful to REPSeOL, TGS–NOPEC, and the CSIC-Institut Jaume Almera (http://geodb.ictja.csic.es) for allowing us to use an unpublished seismic data from the Gulf of Cadiz. We thank J. Aguire (UGR, Spain) for comments and suggestions concerning the Pliocene and Quaternary outcrops, B. van den Berg (USAL) for organizing a thought-provoking field-trip to Cadiz, Spain in November, 2014, M. Ángel Caja, L. García Diego, and J. Tritlla (REPSOL) for provenance and diagenetic analysis of early Pliocene sandstones and debrites, and L.J. Lourens (Utrecht University) for providing us the eccentricity and 200-Kys glacio-eustatic sea-level curves included in the Figure 16. Both Prof. D.A.V. Stow (Heriot-Watt Univ., UK) and F.J. Hernández-Molina (RHUL, UK), as the main co-proponents of the IODP Proposal 644 and the co-chiefs of the IODP Exp. 339, thanks to IODP, Exp. IODP 339 Scientists; JR crew and technicians, as well as all people, institutions and companies involved in making IODP a success since 2003. Finally, we also thank the editor, Gert J. De Lange and the reviewers T. Mulder (Bourdeaux Univ.); D. Van Rooij (Ghent Univ) and J. Duarte (Monash Univ.) for their very positive and helpful feedback and discussions in publishing this research.Peer reviewedPublisher PD
MEIS1, PREP1, and PBX4 Are Differentially Expressed in Acute Lymphoblastic Leukemia: Association of MEIS1 Expression with Higher Proliferation and Chemotherapy Resistance
<p>Abstract</p> <p>Background</p> <p>The Three-amino acid-loop-extension (<it>TALE</it>) superfamily of homeodomain-containing transcription factors have been implicated in normal hematopoiesis and in leukemogenesis and are important survival, differentiation, and apoptosis pathway modulators. In this work, we determined the expression levels of <it>TALE </it>genes in leukemic-derived cell lines, in blood samples of patients with Acute lymphoblastic leukemia (ALL), and in the blood samples of healthy donors.</p> <p>Results</p> <p>Here we show increased expression of <it>MEIS1, MEIS2, </it>and <it>PREP1 </it>genes in leukemia-derived cell lines compared with blood normal cells. High levels of <it>MEIS1 </it>and <it>PREP1</it>, and low levels of <it>PBX4 </it>expression were also founded in samples of patients with ALL. Importantly, silencing of <it>MEIS1 </it>decreases the proliferation of leukemia-derived cells but increases their survival after etoposide treatment. Etoposide-induced apoptosis induces down-regulation of MEIS1 expression or <it>PREP1 </it>up-regulation in chemotherapy-resistant cells.</p> <p>Conclusions</p> <p>Our results indicate that up-regulation of <it>MEIS1 </it>is important for sustaining proliferation of leukemic cells and that down-regulation of <it>MEIS1 </it>or up-regulation of <it>PREP1 </it>and <it>PBX </it>genes could be implicated in the modulation of the cellular response to chemotherapeutic-induced apoptosis.</p
No silver bullet for digital soil mapping: country-specific soil organic carbon estimates across Latin America.
Country-specific soil organic carbon (SOC) estimates are the baseline for the Global SOC Map of the Global Soil Partnership (GSOCmap-GSP). This endeavor is key to explaining the uncertainty of global SOC estimates but requires harmonizing heterogeneous datasets and building country-specific capacities for digital soil mapping (DSM).We identified country-specific predictors for SOC and tested the performance of five predictive algorithms for mapping SOC across Latin America. The algorithms included support vector machines (SVMs), random forest (RF), kernel-weighted nearest neighbors (KK), partial least squares regression (PL), and regression kriging based on stepwise multiple linear models (RK). Country-specific training data and SOC predictors (5 x 5 km pixel resolution) were obtained from ISRIC - World Soil Information. Temperature, soil type, vegetation indices, and topographic constraints were the best predictors for SOC, but country-specific predictors and their respective weights varied across Latin America. We compared a large diversity of country-specific datasets and models, and were able to explain SOC variability in a range between ~ 1 and ~ 60 %, with no universal predictive algorithm among countries. A regional (n = 11 268 SOC estimates) ensemble of these five algorithms was able to explain ~ 39% of SOC variability from repeated 5-fold cross-validation.We report a combined SOC stock of 77.8 +- 43.6 Pg (uncertainty represented by the full conditional response of independent model residuals) across Latin America. SOC stocks were higher in tropical forests (30 +- 16.5 Pg) and croplands (13 +- 8.1 Pg). Country-specific and regional ensembles revealed spatial discrepancies across geopolitical borders, higher elevations, and coastal plains, but provided similar regional stocks (77.8 +- 42.2 and 76.8 +- 45.1 Pg, respectively). These results are conservative compared to global estimates (e.g., SoilGrids250m 185.8 Pg, the Harmonized World Soil Database 138.4 Pg, or the GSOCmap-GSP 99.7 Pg). Countries with large area (i.e., Brazil, Bolivia, Mexico, Peru) and large spatial SOC heterogeneity had lower SOC stocks per unit area and larger uncertainty in their predictions. We highlight that expert opinion is needed to set boundary prediction limits to avoid unrealistically high modeling estimates. For maximizing explained variance while minimizing prediction bias, the selection of predictive algorithms for SOC mapping should consider density of available data and variability of country-specific environmental gradients. This study highlights the large degree of spatial uncertainty in SOC estimates across Latin America. We provide a framework for improving country-specific mapping efforts and reducing current discrepancy of global, regional, and country-specific SOC estimates
VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory
VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l.
in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design,
construction techniques and data acquisition system of the HAWC observatory.
HAWC is an air-shower array currently under construction at the same site of
VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water
Cherenkov detectors and two different data acquisition systems. It was in
operation between October 2011 and May 2012 with an average live time of 30%.
Besides the scientific verification purposes, the eight months of data were
used to obtain the results presented in this paper: the detector response to
the Forbush decrease of March 2012, and the analysis of possible emission, at
energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages,
10 figures). Corresponding authors: A.Marinelli and D.Zaboro
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