Publications by authors named "Carlos Fuentes"

11 Publications

  • Page 1 of 1

Protection barrier in colonoscopy to prevent transmission through feces in times of COVID-19.

VideoGIE 2020 Dec 3;5(12):618-621. Epub 2020 Sep 3.

Department of Gastroenterology, Clínica Universitaria Colombia, Fundación Universitaria Sanitas, Bogota, Colombia.

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http://dx.doi.org/10.1016/j.vgie.2020.07.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7468317PMC
December 2020

Use of a new face shield for patients of the endoscopy unit to avoid aerosol exchange in the COVID-19 era.

VideoGIE 2020 Nov 4;5(11):522-524. Epub 2020 Jul 4.

Department of Gastroenterology, Fundación Universitaria Sánitas, Clínica Universitaria Colombia, Bogota, Colombia.

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http://dx.doi.org/10.1016/j.vgie.2020.05.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7334143PMC
November 2020

Wetting dynamics and surface energy components of single carbon fibers.

J Colloid Interface Sci 2019 Dec 7;557:349-356. Epub 2019 Sep 7.

Department of Materials Engineering, KU Leuven, Leuven 3001, Belgium.

Hypothesis: Measuring contact angles made by liquids around individual carbon fibers (CFs) using the Wilhelmy technique is a conventional method to evaluate their surface properties. However, despite its apparent simplicity, inaccurate measurements of capillary forces and wetted lengths, due to the fineness of the CFs, as well as an improper selection of probe liquids can lead to incorrect contact angle and surface energy calculations, leading to an erroneous characterization of their surface properties.

Experiments: In this study, dynamic wetting experiments of individual CFs were performed in ethylene glycol, diiodomethane, and formamide based on the Wilhelmy method. Capillary forces exerted on the CFs were recorded and analyzed in detail to calculate reliable dynamic contact angles at different contact-line velocities. The molecular-kinetic theory (MKT) and hydrodynamic approach (HD) were then used to model the experimental data and to obtain static contact angles.

Findings: The analysis shows that the experimental data are in good agreement with the linear MKT suggesting that the dominant channel of energy dissipation at the contact line is the contact-line friction. From the predicted static advancing contact angle values, the surface energy components of the CFs could be obtained thus providing a way to characterize their interfacial properties and predict their compatibility with polymer matrices. This study furthermore points out the importance of choosing the correct combination of test fluids to obtain reliable surface energy results.
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http://dx.doi.org/10.1016/j.jcis.2019.09.026DOI Listing
December 2019

Proteomic study of the membrane components of signalling cascades of Botrytis cinerea controlled by phosphorylation.

Sci Rep 2019 07 8;9(1):9860. Epub 2019 Jul 8.

Andalusian Center for Grape and Grapevine Research (IVAGRO), Microbiology Lab, University of Cadiz, Puerto Real, 11510, Spain.

Protein phosphorylation and membrane proteins play an important role in the infection of plants by phytopathogenic fungi, given their involvement in signal transduction cascades. Botrytis cinerea is a well-studied necrotrophic fungus taken as a model organism in fungal plant pathology, given its broad host range and adverse economic impact. To elucidate relevant events during infection, several proteomics analyses have been performed in B. cinerea, but they cover only 10% of the total proteins predicted in the genome database of this fungus. To increase coverage, we analysed by LC-MS/MS the first-reported overlapped proteome in phytopathogenic fungi, the "phosphomembranome" of B. cinerea, combining the two most important signal transduction subproteomes. Of the 1112 membrane-associated phosphoproteins identified, 64 and 243 were classified as exclusively identified or overexpressed under glucose and deproteinized tomato cell wall conditions, respectively. Seven proteins were found under both conditions, but these presented a specific phosphorylation pattern, so they were considered as exclusively identified or overexpressed proteins. From bioinformatics analysis, those differences in the membrane-associated phosphoproteins composition were associated with various processes, including pyruvate metabolism, unfolded protein response, oxidative stress response, autophagy and cell death. Our results suggest these proteins play a significant role in the B. cinerea pathogenic cycle.
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http://dx.doi.org/10.1038/s41598-019-46270-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6614480PMC
July 2019

Validation of the imperial college surgical assessment device for spinal anesthesia.

BMC Anesthesiol 2017 Sep 29;17(1):131. Epub 2017 Sep 29.

Anesthesiology Department, School of Medicine, Pontificia Universidad Catolica de Chile, Marcoleta 367, 8330024, Santiago, Chile.

Background: Traditionally, technical proficiency for spinal anesthesia has been assessed using observational scales such as global rating scales or task specific checklists. However more objective metrics are required in order to improve novice's training programs. The aim of this study is to validate the hand motion analysis of the Imperial College Surgical Assessment Device (ICSAD) in a simulated model of spinal anesthesia.

Methods: Three groups of physicians with different levels of experience were video recorded performing a spinal anesthesia in a simulated lumbar puncture torso. Participants' technical performance was assessed with ICSAD, a Global Rating Scale (GRS) and a specific Checklist. Differences between the 3 groups were determined by Kruskal-Wallis test with post hoc Dunn's correction for multiple comparisons. Spearman correlation coefficient between ICSAD variables and the scores of the observational scales were calculated to establish concurrent validity.

Results: Thirty subjects participated in the study: ten novice (first year residents), 10 intermediate (third year residents) and 10 experts (attending anesthesiologists). GRS scores were significantly higher in experts, than intermediates and novices. Regarding total path length, number of movements and procedural time measured with ICSAD, all groups had significant differences between them (p = 0.026, p = 0.045 and p = 0.005 respectively). Spearman correlation coefficient was -0,46 (p = 0.012) between total path length measured with ICSAD and GRS scores.

Conclusions: This is the first validation study of ICSAD as an assessment tool for spinal anesthesia in a simulated model. Using ICSAD can discriminate proficiency between expert and novices and correlates with previously validated GRS. Its use in the assessment of spinal anesthesia proficiency provides complementary data to existing tools. Our results could be used to design future training programs with reliable goals to accomplish.
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http://dx.doi.org/10.1186/s12871-017-0422-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5622479PMC
September 2017

Spreading Dynamics of Molten Polymer Drops on Glass Substrates.

Langmuir 2017 08 18;33(34):8447-8454. Epub 2017 Aug 18.

Department of Materials Engineering, KU Leuven , 3001 Leuven, Belgium.

Wetting dynamics drive numerous processes involving liquids in contact with solid substrates with a wide range of geometries. The spreading dynamics of organic liquids and liquid metals at, respectively, room temperature and >1000 °C have been studied extensively, both experimentally and numerically; however, almost no attention has been paid to the wetting behavior of molten drops of thermoplastic polymers, despite its importance, for example, in the processing of fiber-reinforced polymer composites. Indeed, the ability of classical theories of dynamic wetting, that is, the hydrodynamic and the molecular-kinetic theories, to model these complex liquids is unknown. We have therefore investigated the spreading dynamics on glass, over temperatures between 200 and 260 °C, of two thermoplastics: polypropylene (PP) and poly(vinylidene fluoride) (PVDF). PP and PVDF showed, respectively, the highest and lowest slip lengths due to their different interactions with the glass substrate. The jump lengths of PP and PVDF are comparable to their Kuhn segment lengths, suggesting that the wetting process of these polymers is mediated by segmental displacements. The present work not only provides evidence of the suitability of the classical models to model dynamic wetting of molten polymers but also advances our understanding of the wetting dynamics of molten thermoplastics at the liquid/solid interface.
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http://dx.doi.org/10.1021/acs.langmuir.7b01500DOI Listing
August 2017

Wettability of a Single Carbon Fiber.

Langmuir 2016 09 12;32(38):9697-705. Epub 2016 Sep 12.

Department of Materials Engineering, KU Leuven , Leuven 3001, Belgium.

Wettability as determined from contact angle measurements is a suitable parameter for characterizing the physical bonding of a polymer matrix and reinforcing fibers, but it is very challenging to measure the capillary force exerted by a probe liquid on a fiber accurately for very fine fibers such as single carbon fibers. Herein, we propose an innovative method for measuring dynamic contact angles with a tensiometer, considering both the intrinsic variability of the carbon fiber diameter and the extremely small amplitude of the capillary forces, allowing the measurement of reliable dynamic contact angles over a large range of contact line velocities. The analysis of the contact angle dynamics by the molecular-kinetic theory permits us to check the relevancy of the measured contact angles and to obtain the static contact angle value, improving the prospect of employing tensiometry to better understand the wetting behavior of carbon fibers.
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http://dx.doi.org/10.1021/acs.langmuir.6b02072DOI Listing
September 2016

Hypothalamic-pituitary-adrenal axis function during perinatal depression.

Neurosci Bull 2015 Jun 2;31(3):338-50. Epub 2015 Mar 2.

National Institute of Perinatology, Mexico City, Mexico,

Abnormal function of the hypothalamic-pituitary-adrenal (HPA) axis is an important pathological finding in pregnant women exhibiting major depressive disorder. They show high levels of cortisol pro-inflammatory cytokines, hypothalamic-pituitary peptide hormones and catecholamines, along with low dehydroepiandrosterone levels in plasma. During pregnancy, the TH2 balance together with the immune system and placental factors play crucial roles in the development of the fetal allograft to full term. These factors, when altered, may generate a persistent dysfunction of the HPA axis that may lead to an overt transfer of cortisol and toxicity to the fetus at the expense of reduced activity of placental 11β-hydroxysteroid dehydrogenase type 2. Epigenetic modifications also may contribute to the dysregulation of the HPA axis. Affective disorders in pregnant women should be taken seriously, and therapies focused on preventing the deleterious effects of stressors should be implemented to promote the welfare of both mother and baby.
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http://dx.doi.org/10.1007/s12264-014-1508-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5563683PMC
June 2015

Exploring epistasis in candidate genes for antisocial personality disorder.

Psychiatr Genet 2011 Jun;21(3):115-24

Department of Psychiatry, Faculty of Medicine, Universidad de Antioquia, Medellin, Colombia.

Objective: To identify and characterize high-order gene-to-gene interactions in antisocial personality disorder (ASPD).

Methods: Participants for case-control study were selected from the inmate male population in Bellavista prison from Medellin. The study included 310 individuals with ASPD and 200 with no ASPD. Diagnoses were made according to a best-estimate procedure based on a semistructured interview (diagnostic interview for genetic studies 3.0). We genotyped some single-nucleotide polymorphisms in candidate genes with main serotonin pathway effects. The gene-gene interaction was examined using the multifactor dimensionality reduction method version 2.0.α. We assessed model sizes of 2 and 3 loci and counted the number of replicates that contained the causal loci in the final best model that was identified using 10-fold cross validation.

Results: We find epistatic interaction with catechol-O-methyl transferase (COMT), tryptophan hydroxylase, and 5-HTR2A (serotonin receptor) with ASPD. This data supports an important role of polymorphism in serotonin receptors and low enzyme activity of COMT for susceptibility to ASPD.

Conclusion: This study suggests that gene interactions between genetic variants in COMT, 5-HTR2A and tryptophan hydroxylase gene would be associated with ASPD and influence the dopamine rewards pathways and modulate serotonin levels in ASPD.
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http://dx.doi.org/10.1097/YPG.0b013e3283437175DOI Listing
June 2011

Kidney in danger: CT findings of blunt and penetrating renal trauma.

Radiographics 2009 Nov;29(7):2033-53

Department of Emergency Radiology, Hospital Universitario Doce De Octubre, Madrid, Spain.

Approximately 10% of all significant blunt abdominal traumatic injuries manifest with renal injury, although it is usually minor. However, renal imaging is indicated in cases of gross hematuria, penetrating trauma with gross or microscopic hematuria, and blunt trauma and shock with gross or microscopic hematuria. Contrast material-enhanced computed tomography (CT) is the imaging modality of choice in the evaluation and management of renal trauma. Contrast-enhanced CT is readily available in emergency departments and can quickly and accurately depict renal injuries as well as associated injuries to other abdominal or retroperitoneal organs. In this way, contrast-enhanced CT provides the anatomic and functional information that is essential for accurate staging. In addition, CT can help detect active hemorrhage and urinary extravasation and is very useful in guiding transcatheter embolization and delineating preexisting disease entities that may predispose kidneys to posttraumatic hemorrhage. With the advent of multidetector CT, imaging is characterized by faster scanning times, increased volume coverage, and improved spatial and temporal resolution. The increased use of CT has been partially responsible for a growing trend toward conservative management of renal trauma, except in cases in which extensive urinary extravasation or devitalized areas of renal parenchyma are found and especially in those cases with associated injuries to other abdominal organs; these cases are particularly prone to complications and usually require surgery.
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http://dx.doi.org/10.1148/rg.297095071DOI Listing
November 2009

Magnet hopitals: A key to reducing the nursing shortage.

Authors:
Carlos Fuentes

Mich Nurse 2002 Feb;75(2):5, 14

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February 2002