Publications by authors named "Guerrero H"

Background: The detection of genetic sequences represents the gold standard procedure for species discrimination, genetic characterisation of tumours, and identification of pathogens. The development of new molecular detection methods, accessible and cost effective, is of great relevance. Biosensors based on plasmonic nanoparticles, such as gold nanoparticles (AuNPs), provide a powerful and versatile platform for highly sensitive, economic, user-friendly and label-free sensing.

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This study investigates the effectiveness of various chemical methods, both ultrasound-assisted and non-assisted, for extracting cellulose from banana pseudostem (BPS) waste, comparing the results with commercial pine and eucalyptus cellulose fibers. Delignification treatments with NaOH (25% and 30%) and HO (8%) were evaluated, applied with both conventional and focused sonication. Ultrasound-assisted methods, particularly with NaOH, achieved cellulose percentages as high as 99.

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Objective: The aim of the study was to describe the clinicopathological profile of patients diagnosed with liver, bile ducts or gallbladder cancer.

Materials And Methods: Between 2006 and 2017, 89 patients (57% female; mean age: 62 years-old) with these cancers were diagnosed at two national hospitals in Lima, Peru.

Results: Most patients (64%) had advanced stages of disease.

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Prelinguistic babbling is a critical phase in infant language development and is best understood in temperate songbirds where it occurs primarily in males at reproductive maturity and is modulated by sex steroids. Parrots of both sexes are icons of tropical vocal plasticity, but vocal babbling is unreported in this group and whether the endocrine system is involved is unknown. Here we show that vocal babbling is widespread in a wild parrot population in Venezuela, ensues in both sexes during the nestling stage, occurs amidst a captive audience of mixed-aged siblings, and is modulated by corticosteroids.

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Unlabelled: The future of health care professional education is moving from a focus on the individual to embrace the health of the larger society. The COVID-19 pandemic has further highlighted the connection between social determinants and the health of populations. There are frameworks and competencies to support the delivery of population health content in the entry-level Doctor of Physical Therapy (DPT) curriculum.

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Genetic resources of have been introduced in several tropical countries with potential for crop development. In Ecuador, the species has been cultivated since the mid-20th century. However, little is known about the diversity and genetic structure of introduced germplasm.

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The pρTx behavior of the binary mixtures n-hexane + isomeric chlorobutane has been studied over the whole composition range at temperatures between 283.15 and 323.15 K and pressures from 0.

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The time required to image large samples is an important limiting factor in SPM-based systems. In multiprobe setups, especially when working with biological samples, this drawback can make impossible to conduct certain experiments. In this work, we present a feedfordward controller based on bang-bang and adaptive controls.

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A focused-ion-beam-assisted technique intended for ultrasmall, hard-magnet fabrication has been developed. By means of ion-beam-induced milling and deposition, reduced-size NdFeB magnets were extracted from a macroscopic quarry and bonded to the surface of a thin-film bulk acoustic resonator (FBAR). Electrical characterization of the FBAR before and after bonding of the magnet was carried out, thus observing both a downshifting of the resonance frequency and a reduction of the quality factor of the resonator.

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Objectives: We sought to identify cross-sectional hepatitis B virus (HBV) and HCV prevalence among Asian Americans at a community health fair and to assess referral rates.

Methods: We determined HBV prevalence with hepatitis B surface antigen (HBsAg), antibodies to hepatitis B core antigen (anti-HBc), and antibodies to hepatitis B surface antigen (anti-HBs). We determined HCV prevalence with hepatitis C antibodies.

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The suprachiasmatic nuclei (SCN) distribute the circadian neural message to the pineal gland which transforms it into a humoral circadian message, the nocturnal melatonin synthesis, which in turn modulates tissues expressing melatonin receptors such as the SCN or the pars tuberalis (PT). Nuclear orphan receptors (NOR), including rorbeta and rev-erbalpha, have been presented as functional links between the positive and negative loops of the molecular clock. Recent findings suggest that these NOR could be the initial targets of melatonin's chronobiotic message within the SCN.

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The combined use of aspirin and clopidogrel is the standard of care for patients with acute coronary syndromes. The risk for perioperative bleeding is considerably increased after coronary artery by-pass graft surgery (CABG). This study was designed to evaluate the effect of antiplatelet therapy on perioperative CABG outcome.

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This review describes the endocrine changes that occur during the annual reproductive cycle of Pygocentrus cariba, Pimelodus blochii, and Oxydoras sifontesi and their relationships with the environmental characteristics of Venezuelan floodplains. Most reproductive studies of teleosts have focused on changes that occur during annual cycles in temperate species but, in tropical fish, this has been examined less frequently. P.

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We describe a micromachined optical fiber current sensor. The sensing element consists of a squared silicon membrane (8 mm long and 20 microm thick) that has a cylindrical permanent magnet (NdFeB alloy, 3-mm diameter, 1.5 mm high) fixed on its central region.

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A new simple and sensitive dilatometer to measure magnetostriction of ribbons has been developed, based on an optical fiber sensor using an annular photodiode. The optical fiber is used bidirectionally, both for emission and detection of light, simplifying the access to the ribbon under test. The working principle is based on the measurement by reflection of the longitudinal displacement of the ribbon end.

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Background: The prognostic value of natriuretic peptides in heart failure (HF) is well established. The objective of this study was to evaluate the role of NT-proBNP in predicting outcome in decompensated HF.

Methods: Patients admitted with decompensated HF to our Internal Medicine Department between November 2002 and April 2004 with at least two measurements of NT-proBNP (within 24 hours of admission and on discharge) were analyzed.

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Oxydoras sifontesi and Pimelodus blochii are seasonal breeder fish. Spawn occurs once a year over a short interval of time, at the beginning of the rainy season. The gonadosomatic index (GSI), and plasma levels of steroid hormones of P.

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The quantitative liver-spleen scan (QLSS) can estimate the functional hepatic mass and the organ volumes by precise measurement of sulfur colloid (SC) distribution. The normal range determined in prior studies was estimated from patients with absence of chronic liver disease in which intense fasting appeared to produce slightly abnormal values. This study was to determine the effect of fasting or fed status and colloid particle size on quantitative measurements from the QLSS in a small cohort of normal individuals.

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The pars tuberalis (PT) of the pituitary represents an important target site for the time-pacing pineal hormone melatonin because it expresses a large number of mt1 receptors. Functional studies suggest that the PT mediates the seasonal effects of melatonin on prolactin (PRL) secretion. The aim of this study was the characterization of the phenotype of melatonin-responsive cells.

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An optical method to determine the nanostructure and the morphology of porous thin films is presented. This procedure is based on the response of a side-polished optical fiber with the film under study, when an adsorption-desorption cycle is carried out. Spectroscopic ellipsometry provides additional information about the optical properties and adsorption behavior of the film.

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We have investigated the photic regulation of melatonin receptors both at the level of binding capacity and mt(1) mRNA expression in the suprachiasmatic nucleus (SCN) and the pars tuberalis (PT) of the pituitary of two species: a highly photoperiodic one, the Siberian hamster, and a nonphotoperiodic one, the Wistar rat. This study has been performed by looking at the effect of a light pulse applied during the night on the two receptor parameters. The results show that the photic regulations of mt(1) mRNA expression and receptor density are distinct from each other in both the SCN and PT of the two species studied.

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The pars tuberalis (PT) of the pituitary is a major neuroendocrine target site for melatonin as it contains a large number of high-affinity melatonin receptors. We have previously shown that melatonin autoregulates the density of its own receptors in the PT. However, whether melatonin regulation includes mRNA expression in vivo is unclear.

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In the Siberian hamster suprachiasmatic nuclei and pars tuberalis of the pituitary, high affinity mt1 melatonin receptors are present. We have previously shown that night applied light pulse induced an increase in mt1 mRNA expression in the suprachiasmatic nuclei of this species, independently of the endogenous melatonin. Here, we report the photic regulation of melatonin receptor density and mRNA expression in the suprachiasmatic nuclei and pars tuberalis of pinealectomized Siberian hamsters and the implication in this control of either the circadian clock or the intergeniculate leaflet.

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