3,061 research outputs found

    Optical photometry of the UCM Lists I and II

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    We present Johnson B CCD photometry for the whole sample of galaxies of the Universidad Complutense de Madrid (UCM) Survey Lists I and II. They constitute a well-defined and complete sample of galaxies in the Local Universe with active star formation. The data refer to 191 S0 to Irr galaxies at an averaged redshift of 0.027, and complement the already published Gunn r, J and K photometries. In this paper the observational and reduction features are discussed in detail, and the new colour information is combined to search for clues on the properties of the galaxies, mainly by comparing our sample with other surveys.Comment: 14 pages, 7 PostScript figures, accepted for publication in A&AS, also available vi ftp at ftp://cutrex.fis.ucm.es/pub/OUT/pag/PAPERS

    Construcción y propiedades psicométricas de la escala de violencia autoinfligida para adolescentes Chiclayo, 2022

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    El presente estudio estableció como objetivo general: Construir la escala de violencia autoinfligida para adolescentes Chiclayo, 2022. La investigación fue aplicada de tipo instrumental y con diseño psicométrico; la muestra fue seleccionada a través de un muestreo no probabilístico por conveniencia, la misma que estuvo conformada por 486 adolescentes entre hombres y mujeres pertenecientes a una institución educativa de Chiclayo. Los principales resultados demostraron que se logró diseñar el modelo teórico de la escala de violencia autoinfligida conformada por las siguientes dimensiones: factores de riesgo, ideación suicida y comportamiento suicida. Con respecto a la validez de contenido se optó por el método juicio de expertos y el coeficiente V de Aiken el cual arrojó valores aceptables (>0.90). Además, se evidenció que los 22 ítems mostraron adecuados índices de asimetría y curtosis (+/-1.5); además adecuados índices de homogeneidad (>83); y cargas factoriales (>0.87). En lo que concierne a la validez de constructo, se demostró que el instrumento se estructuró en 3 factores compuestos por 20 reactivos con adecuados índices de bondad de ajuste. Por último, a través del coeficiente Alpha y Omega, se obtuvo un valor de 0,99, lo que demuestra una excelente confiabilidad de la escala de violencia autoinfligid

    Altered response of adenylate cyclase to parathyroid hormone during compensatory renal growth

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    Altered response of adenylate cyclase to parathyroid hormone during compensatory renal growth. The loss of renal mass is associated with functional adaptations in the remaining nephrons to maintain homeostasis. Although parathyroid hormone (PTH) is important in the adaptations to phosphate, the mechanisms are not completely defined. In the present studies we examined the response of the adenylate cyclase system to PTH in renal cortical membranes of rat kidneys ten days after unilateral nephrectomy. The kidneys obtained at the time of the initial nephrectomy were used as controls. Unilateral nephrectomy resulted in contralateral compensatory renal growth, as demonstrated by a 24 ± 4.7% (P < 0.01) increase in weight in the remaining kidney. Glomerular filtration rate (GFR) after unilateral nephrectomy was 62% of the control, while basal fractional phosphate excretion was higher in rats with unilateral nephrectomy (7.7 ± 2.1% vs. 2.9 ± 0.8%, P < 0.05). PTH infusion resulted in a similar increase of fractional phosphate excretion and urinary cAMP in both groups. In the absence of added guanine nucleotides, PTH-dependent adenylate cyclase activity in cortical membranes from kidneys with compensatory growth was decreased as compared to controls (Vmax807.5 ± 62.7 pmol cAMP/mg protein/30min vs. 1,384.8 ± 116.1, respectively, P < 0.01). The apparent affinity for PTH stimulation of adenylate cyclase (Kact) was unchanged. Magnesium-dependent adenylate cyclase activity was also decreased in the membranes from kidneys with compensatory growth. However, the kinetics of adenylate cyclase for the substrates ATP-Mg or ATP-Mn were similar. The addition of Gpp(NH)p resulted in a similar maximal response to PTH in the two groups, indicating an increased response of the enzyme to PTH in the presence of the guanine nucleotide. Cholera toxin-dependent ADP-ribosylation of the stimulatory guanine nucleotide binding protein (Gs) showed a marked decrease in the apparent content of the alpha subunit in membranes from kidneys with compensatory growth compared to controls. On the contrary, pertussis toxin-dependent ADP-ribosylation of the inhibitory guanine nucleotide binding protein (Gi) did not show differences in the content of the alpha subunit in both groups of membranes. Since the transduction of the hormone signal from the receptor is mediated by G proteins, the present studies suggest that during compensatory renal growth a decrease in the alpha subunit of Gs could account for the impaired response of adenylate cyclase to PTH in vitro, which could be overcome by high concentrations of guanine nucleotides

    Independent evolution of macrophage-tropism and increased charge between HIV-1 R5 envelopes present in brain and immune tissue

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    Background: Transmitted HIV-1 clade B or C R5 viruses have been reported to infect macrophages inefficiently, while other studies have described R5 viruses in late disease with either an enhanced macrophage-tropism or carrying envelopes with an increased positive charge and fitness. In contrast, our previous data suggested that viruses carrying non-macrophage-tropic R5 envelopes were still predominant in immune tissue of AIDS patients. To further investigate the tropism and charge of HIV-1 viruses in late disease, we evaluated the properties of HIV-1 envelopes amplified from immune and brain tissues of AIDS patients with neurological complications. Results: Almost all envelopes amplified were R5. There was clear compartmentalization of envelope sequences for four of the five subjects. However, strong compartmentalization of macrophage-tropism in brain was observed even when brain and immune tissue envelope sequences were not segregated. R5 envelopes from immune tissue of four subjects carried a higher positive charge compared to brain envelopes. We also confirm a significant correlation between macrophage tropism and sensitivity to soluble CD4, a weak association with sensitivity to the CD4 binding site antibody, b12, but no clear relationship with maraviroc sensitivity. Conclusions: Our study shows that non-macrophage-tropic R5 envelopes carrying gp120s with an increased positive charge were predominant in immune tissue in late disease. However, highly macrophage-tropic variants with lower charged gp120s were nearly universal in the brain. These results are consistent with HIV-1 R5 envelopes evolving gp120s with an increased positive charge in immune tissue or sites outside the brain that likely reflect an adaptation for increased replication or fitness for CD4+ T-cells. Our data are consistent with the presence of powerful pressures in brain and in immune tissues selecting for R5 envelopes with very different properties; high macrophage-tropism, sCD4 sensitivity and low positive charge in brain and non-macrophage-tropism, sCD4 resistance and high positive charge in immune tissue

    1-(2-Chlorobenzyloxy)-3-[1,2,3]triazol-1-yl-propan-2-ol Derivatives: Synthesis, Characterization, and DFT-Based Descriptors Analysis

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    A novel series of 1-(2-chlorobenzyloxy)-3-[1,2,3]triazol-1-yl-propan-2-ol derivatives was designed and synthesized using copper catalyzed alkyne-azide cycloaddition in the key step. Theoretical investigation of molecular and electronic properties by means of global and local reactivity indexes of the synthetized compounds was carried out, using DFT (Density Functional Theory) at PBEPBE/6-31++G∗∗ levelCONACY

    Stellar populations in local star-forming galaxies. I.-Data and modelling procedure

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    We present an analysis of the integrated properties of the stellar populations in the Universidad Complutense de Madrid Survey of Halpha-selected galaxies. In this paper, the first of a series, we describe in detail the techniques developed to model star-forming galaxies using a mixture of stellar populations, and taking into account the observational uncertainties. We assume a recent burst of star formation superimposed on a more evolved population. The effects of the nebular continuum, line emission and dust attenuation are taken into account. We also test different model assumptions including the choice of specific evolutionary synthesis model, initial mass function, star formation scenario and the treatment of dust extinction. Quantitative tests are applied to determine how well these models fit our multi-wavelength observations for the UCM sample. Our observations span the optical and near infrared, including both photometric and spectroscopic data. Our results indicate that extinction plays a key role in this kind of studies, revealing that low- and high-extinction objects may require very different extinction laws and must be treated differently. We also demonstrate that the UCM Survey galaxies are best described by a short burst of star formation occurring within a quiescent galaxy, rather than by continuous star formation. A detailed discussion on the inferred parameters, such as the age, burst strength, metallicity, star formation rate, extinction and total stellar mass for individual objects, is presented in paper II of this series.Comment: 18 pages, 8 PostScript figures, minor changes to match the published versio

    Luminosity and Stellar Mass Functions of Local Star-Forming Galaxies

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    We present the optical and near-infrared luminosity and mass functions of the local star-forming galaxies in the Universidad Complutense de Madrid Survey. A bivariate method which explicitly deals with the Halpha selection of the survey is used when estimating these functions. Total stellar masses have been calculated on a galaxy-by-galaxy basis taking into account differences in star formation histories. The main difference between the luminosity distributions of the UCM sample and the luminosity functions of the local galaxy population is a lower normalization (phi^*), indicating a lower global volume density of UCM galaxies. The typical near-infrared luminosity (L^*) of local star-forming galaxies is fainter than that of normal galaxies. This is a direct consequence of the lower stellar masses of our objects. However, at optical wavelengths (B and r) the luminosity enhancement arising from the young stars leads to M^* values that are similar to those of normal galaxies. The fraction of the total optical and near infrared luminosity density in the local Universe associated with star-forming galaxies is 10-20%. Fitting the total stellar mass function using a Schechter parametrization we obtain alpha=-1.15+/-0.15, log({M}^*)=10.82+/-0.17 Msun and log(phi^*)=-3.04+/-0.20 Mpc^{-3}. This gives an integrated total stellar mass density of 10^{7.83+/-0.07} Msun Mpc^{-3} in local star-forming galaxies (H_0=70 km s^{-1} Mpc^{-1}, Omega_M=0.3, Lambda=0.7). The volume-averaged burst strength of the UCM galaxies is b=0.04+/-0.01, defined as the ratio of the mass density of stars formed in recent bursts (age<10 Myr) to the total stellar mass density in UCM galaxies. Finally, we derive that, in the local Universe, (13+/-3)% of the total baryon mass density in the form of stars is associated with star-forming galaxies.Comment: 12 pages, 2 PostScript figures, published in ApJL. Minor changes to match the published versio

    HIV-1 non-macrophage-tropic R5 envelope glycoproteins are not more tropic for entry into primary CD4+ T-cells than envelopes highly adapted for macrophages

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    BACKGROUND: Non-mac-tropic HIV-1 R5 viruses are predominantly transmitted and persist in immune tissue even in AIDS patients who carry highly mac-tropic variants in the brain. Non-mac-tropic R5 envelopes (Envs) require high CD4 levels for infection contrasting with highly mac-tropic Envs, which interact more efficiently with CD4 and mediate infection of macrophages that express low CD4. Non-mac-tropic R5 Envs predominantly target T-cells during transmission and in immune tissue where they must outcompete mac-tropic variants. Here, we investigated whether Env+ pseudoviruses bearing transmitted/founder (T/F), early and late disease non-mac-tropic R5 envelopes mediated more efficient infection of CD4+ T-cells compared to those with highly mac-tropic Envs. RESULTS: Highly mac-tropic Envs mediated highest infectivity for primary T-cells, Jurkat/CCR5 cells, myeloid dendritic cells, macrophages, and HeLa TZM-bl cells, although this was most dramatic on macrophages. Infection of primary T-cells mediated by all Envs was low. However, infection of T-cells was greatly enhanced by increasing virus attachment with DEAE dextran and spinoculation, which enhanced the three Env+ virus groups to similar extents. Dendritic cell capture of viruses and trans-infection also greatly enhanced infection of primary T-cells. In trans-infection assays, non-mac-tropic R5 Envs were preferentially enhanced and those from late disease mediated levels of T-cell infection that were equivalent to those mediated by mac-tropic Envs. CONCLUSIONS: Our results demonstrate that T/F, early or late disease non-mac-tropic R5 Envs do not preferentially mediate infection of primary CD4+ T-cells compared to highly mac-tropic Envs from brain tissue. We conclude that non-macrophage-tropism of HIV-1 R5 Envs in vitro is determined predominantly by a reduced capacity to target myeloid cells via low CD4 rather than a specific adaptation for T-cells entry that precludes macrophage infection

    No detection of CD4-independent human immunodeficiency virus 1 envelope glycoproteins in brain tissue of patients with or without neurological complications

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    Macrophage (mac)-tropic human immnunodeficiency virus type 1 (HIV-1) and simian immnunodeficiency virus (SIV) in brain are associated with neurological disease. Mac-tropic HIV-1 evolves enhanced CD4 interactions that enable macrophage infection via CD4, which is in low abundance. In contrast, mac-tropic SIV is associated with CD4-independent infection via direct CCR5 binding. Recently, mac-tropic simian-human immunodeficiency virus (SHIV) from macaque brain was also reported to infect cells via CCR5 without CD4. Since SHIV envelope proteins (Envs) are derived from HIV-1, we tested more than 100 HIV-1 clade B Envs for infection of CD4-negative, CCR5(+) Cf2Th/CCR5 cells. However, no infection was detected. Our data suggest that there are differences in the evolution of mac-tropism in SIV and SHIV compared to HIV-1 clade B due to enhanced interactions with CCR5 and CD4, respectively
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