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result(s) for
"Perez, Esther"
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Exploring and Re-Assessing Reverse Anomeric Effect in 2-Iminoaldoses Derived from Mono- and Polynuclear Aromatic Aldehydes
by
Pérez, Esther M. S.
,
Matamoros, Esther
,
Palacios, Juan C.
in
2-iminoaldoses
,
Aldehydes
,
Amino acids
2024
A curious and noticeable structural feature in Schiff bases from 2-aminoaldoses is the fact that imino tautomers arranged equatorially in the most stable ring conformation exhibit a counterintuitive reverse anomeric effect (RAE) in the mutarotational equilibrium, i.e., the most stable and abundant anomer is the equatorial one (β). As shown by our very recent research, this effect arises from the total or partial inhibition of the exo-anomeric effect due to the presence of an intramolecular hydrogen bond between the anomeric hydroxyl and the iminic nitrogen in the axial anomer (α). When the Schiff base adopts either an enamine structure or the imino group is protonated, the exo-anomeric effect is restored, and the axial α-anomer becomes the most stable species. Although the intramolecular H-bonding should appropriately be interpreted as a genuine stereoelectronic effect, the magnitude of the RAE could be affected by other structural parameters. Herein and through a comprehensive analysis of benzylidene, cinnamylidene, naphthalene, phenanthrene, and anthracene aldehydes, we show the robustness of the RAE effect, which is similar in extent to simple aldehydes screened so far, irrespective of the size and/or hydrophobicity of the substituent at the nitrogen atom.
Journal Article
Data Mining and Machine Learning Techniques for Aerodynamic Databases: Introduction, Methodology and Potential Benefits
2020
Machine learning and data mining techniques are nowadays being used in many business sectors to exploit the data in order to detect trends, discover certain features and patters, or even predict the future. However, in the field of aerodynamics, the application of these techniques is still in the initial stages. This paper focuses on exploring the benefits that machine learning and data mining techniques can offer to aerodynamicists in order to extract knowledge from the CFD data and to make quick predictions of aerodynamic coefficients. For this purpose, three aerodynamic databases (NACA0012 airfoil, RAE2822 airfoil and 3D DPW wing) have been used and results show that machine-learning and data-mining techniques have a huge potential also in this field.
Journal Article
Conditional Depletion of the Chlamydomonas Chloroplast ClpP Protease Activates Nuclear Genes Involved in Autophagy and Plastid Protein Quality Control
2014
Plastid protein homeostasis is critical during chloroplast biogenesis and responses to changes in environmental conditions. Proteases and molecular chaperones involved in plastid protein quality control are encoded by the nucleus except for the catalytic subunit of ClpP, an evolutionarily conserved serine protease. Unlike its Escherichia coli ortholog, this chloroplast protease is essential for cell viability. To study its function, we used a recently developed system of repressible chloroplast gene expression in the alga Chlamydomonas reinhardtii. Using this repressible system, we have shown that a selective gradual depletion of ClpP leads to alteration of chloroplast morphology, causes formation of vesicles, and induces extensive cytoplasmic vacuolization that is reminiscent of autophagy. Analysis of the transcriptome and proteome during ClpP depletion revealed a set of proteins that are more abundant at the protein level, but not at the RNA level. These proteins may comprise some of the ClpP substrates. Moreover, the specific increase in accumulation, both at the RNA and protein level, of small heat shock proteins, chaperones, proteases, and proteins involved in thylakoid maintenance upon perturbation of plastid protein homeostasis suggests the existence of a chloroplast-to-nucleus signaling pathway involved in organelle quality control. We suggest that this represents a chloroplast unfolded protein response that is conceptually similar to that observed in the endoplasmic reticulum and in mitochondria.
Journal Article
Perceived access and barriers to care among illicit drug users and hazardous drinkers: findings from the Seek, Test, Treat, and Retain data harmonization initiative (STTR)
by
Gwadz, Marya
,
Trejo, Maria Esther Perez
,
Cunningham, William E.
in
Acquired immune deficiency syndrome
,
Adult
,
African Americans
2018
Background
Illicit drug use (DU) and hazardous drinking (HD) among marginalized populations may be associated with greater barriers to care.
Methods
We used baseline data on the participants of the Seek, Test, Treat, and Retain data harmonization initiative. DU includes use of any illicit drugs within the past 6 months. HD was defined as scores ≥8 for men and ≥ 7 for women on Alcohol Use Disorders Identification Test within the past 12 months. Social support scores were assigned by summing scores from individual questions related to social support. Two outcomes for multivariable regression models and mediation analysis were perceived access to care and perceived barriers to care scores, calculated from summated points from individual questions within each domain. All models were adjusted for age, gender, race/ethnicity, and social support and stratified by HIV status.
Results
Among 1403 illicit drug users and 4984 non-drug users, the mean age was 39.6 ± 12.2 years old, 71% were male, 57% African Americans, and 39% Hispanic/Latinos. Over 25% reported difficulties in covering medical costs and finding transportation to health care facilities and greater proportions of drug users and hazardous drinkers reported these issues than non-DU/non-HD. In multivariable models, DU and HD were both independently associated with having greater barriers to care (β: 0.49 (95% confidence interval: 0.19 to 0.79)
p
< 0.01; 0.31 (0.18 to 0.45) < 0.01) in HIV-negative participants. Neither DU nor HD was strongly associated with barriers to care for HIV-positive participants. Social support was associated with better perceived access to care and fewer barriers to care in the HIV-negative participants.
Conclusion
The current study found that financial burdens of care, logistical difficulties in accessing care, and low social support were common challenges among individuals using illicit drugs and/or drinking hazardously. Addressing structural barriers and strengthening social support may be important strategies to improve health care among marginalized populations, regardless of HIV status.
Journal Article
Hospital and outpatient models for Hematopoietic Stem Cell Transplantation: A systematic review of comparative studies for health outcomes, experience of care and costs
by
Kwon, Mi
,
Nuño-Solinís, Roberto
,
Urizar, Elena
in
Ambulatory medical care
,
Autografts
,
Biology and Life Sciences
2021
The number of Hematopoietic Stem Cell Transplantations has risen in the past 20 years. The practice of outpatient Hematopoietic Stem Cell Transplantation programs is increasing in an attempt to improve the quality of patient care and reduce the demand for hospital admission. A systematic review of 29 comparative studies between in-hospital and outpatient treatment of Hematopoietic Stem Cell Transplantation, with no restriction by outpatient regime was conducted. This study aims to analyse the current evidence on the effects of the outpatient model on patient-centred outcomes, comparing both in-hospital and outpatient models for autologous and allogeneic HSCT using the Triple Aim framework: health outcomes, costs and experience of care. We found evidence on improved health outcomes and quality of life, on enhanced safety and effectiveness and on reduced overall costs and hospital stays, with similar results on overall survival rates comparing both models for autologous and allogeneic patients. We also found that the outpatient Hematopoietic Stem Cell Transplantation is a safe practice as well as less costly, it requires fewer days of hospital stay both for autologous and allogeneic transplantations. Under a situation of an increasing number of transplants, rising healthcare costs and shortages of hospital capacity, incorporating outpatient models could improve the quality of care for people requiring Hematopoietic Stem Cell Transplantation programs.
Journal Article
Management of Latent Tuberculosis Infection Among Healthcare Workers
by
Schneider, William J.
,
Perez, Esther Arguello
,
Brown, Arthur E.
in
Adult
,
and Commentaries
,
Antitubercular Agents - adverse effects
2017
The risk of infection with Mycobacterium tuberculosis among healthcare workers (HCWs) is estimated to be higher than the general population. However, HCW acceptance and compliance with available latent tuberculosis infection (LTBI) treatment regimens has been problematic. Recently, regimens have become available that might improve HCW acceptance and compliance with LTBI treatment.
A retrospective single-center review of Employee Health and Wellness Services records of all HCWs diagnosed with LTBI was conducted. HCWs diagnosed with LTBI were offered 9-month isoniazid (INH), 4-month rifampin (RIF), weekly rifapentine/isoniazid (RPT/INH) for 12 weeks, or no treatment. Acceptance, completion rates, and side effects were reported for each regimen. Comparisons of regimens were assessed using Fisher exact test.
Between 2005 and 2014, 363 of 927 (39%) HCWs diagnosed with LTBI accepted treatment. Of 363, 202 chose INH, 106 RIF, and 55 RPT/INH. Completion rates for each regimen were 58%, 80%, and 87%, respectively. HCWs were significantly more likely to have completed treatment with RIF (P < .0001) or RPT/INH (P < .0001) than INH. Rates of discontinuation owing to side effects were 35% for INH, 21% for RIF, and 10% for RPT/INH. Discontinuation of therapy due to side effects was significantly more frequent in the INH than the RPT/INH group (P = .0042).
Completion of RIF and RPT/INH for LTBI in an HCW population is more likely than INH. Rates of discontinuation due to side effects were lower among those taking RPT/INH. Shorter LTBI treatment regimens should be more widely considered for HCWs in the United States.
Journal Article
On the application of surrogate regression models for aerodynamic coefficient prediction
by
Paulete-Periáñez, Carlos
,
Andrés-Pérez, Esther
in
Aerodynamic coefficients
,
Aerodynamics
,
Aeronautics
2021
Computational fluid dynamics (CFD) simulations are nowadays been intensively used in aeronautical industries to analyse the aerodynamic performance of different aircraft configurations within a design process. These simulations allow to reduce time and cost compared to wind tunnel experiments or flight tests. However, for complex configurations, CFD simulations may still take several hours using high-performance computers to deliver results. For this reason, surrogate models are currently starting to be considered as a substitute of the CFD tool with a reasonable prediction. This paper presents a review on surrogate regression models for aerodynamic coefficient prediction, in particular for the prediction of lift and drag coefficients. To compare the behaviour of the regression models, three different aeronautical configurations have been used, a NACA0012 airfoil, a RAE2822 airfoil and 3D DPW wing. These databases are also freely provided to the scientific community to allow other researchers to make further comparison with other methods.
Journal Article
Game-Based Learning: Increasing the Logical-Mathematical, Naturalistic, and Linguistic Learning Levels of Primary School Students
by
Fernández García, L. Carlota
,
del Moral Pérez, M. Esther
,
Guzmán Duque, Alba P.
in
Academic Ability
,
Aprendizaje basado en juegos
,
based learning
2018
Game-based learning is an innovative methodology that takes advantage of the educational potential offered by videogames in general and serious games in particular to boost training processes, thus making it easier for users to achieve motivated learning. The present paper focuses on the description of the Game to Learn Project, which has as its aim not only to promote the use of serious games and digital mini-games for the development of Multiple Intelligences, but also to analyse whether this methodology results in increased learning. Teachers assessed the level achieved by primary education students (N=119) in each learning category, before and after participating in the project, by means of a qualitative instrument. Finally, after corresponding analysis through descriptive statistical techniques, bivariate correlations, and ANOVA, the results showed significant differences between children’s learning levels in logical-mathematical, naturalistic and linguistic abilities before and after their participation in this innovative project, thus revealing a widespread increase in every indicator.
Journal Article
Blasting extrusion pretreatment of sweet sorghum bagasse for enhanced enzymatic saccharification and ethanol production using Pichia kudriavzevii ATCC 20,381
by
Heredia-Olea, Erick
,
Perez-Perez, David A.
,
Pérez-Carrillo, Esther
in
Arabinose
,
Bagasse
,
Biochemical Engineering
2025
Blasting extrusion pretreatment (BEP) was evaluated for obtaining sugar enriched saccharified extracts from sweet sorghum bagasse (SSB) for ethanol fermentation. A factorial design was used for studying the effect of last barrel zone temperature (T
LBZ
) and screw configuration (SC) on carbohydrate release and extraction yield. The experiment with a higher total carbohydrate release was selected (BEP + ES) for a posterior 72 h fermentation and compared against enzymatic saccharified (ES) SSB without using BEP. Fermentation was performed at 28 °C, pH 5.0 and 10% of solids loading (BEP + ES and ES) using the stress tolerant yeast
Pichia kudriavzevii
ATCC 203,081 for ethanol production. In BEP experiments, screw configuration with one polygon element and a shear zone consisting of 7 reverse elements operating at a T
LBZ
of 190 °C resulted in the highest carbohydrate release after enzymatic saccharification, achieving a 3-fold increase compared to control. BEP enhanced carbohydrate availability and lignocellulosic biomass degradation activity (enzymatic saccharification and
P. kudravzevii
fermentation). Ethanol production usining
P. kudriavzevii
with BEP + ES was 8.65-fold higher than the ES control after 72-h fermentation. Higher initial total carbohydrate (3-fold) and fermentable amino nitrogen (FAN) in BEP + ES (12.41-fold higher) improved SSB fermentability and thus ethanol yield. Glucose was fully consumed in the BEP + ES fermentation, while 91.62% was consumed in the ES experiment. Xylose and mannose/arabinose consumption varied by treatment, but
P. kudriavzevvi
displayed the ability to co-utilize pentoses and hexoses during fermentation. Compared to previous traditional twin-screw extrusion and ES, BEP enhanced SSB carbohydrate release during enzymatic saccharification, and carbohydrate consumption and ethanol production during fermentation.
Journal Article
Lysine Demethylase 1 Has Demethylase-Dependent and Non-Canonical Functions in Myofibroblast Activation in Systemic Sclerosis
by
Del Galdo, Francesco
,
Perez Barreiro, Esther
,
Riobo-Del Galdo, Natalia A.
in
Autoimmune diseases
,
Biopsy
,
Chromatin
2025
Systemic sclerosis (SSc) is an autoimmune disease of unknown aetiology characterised by vasculopathy with progressive fibrosis of the skin and internal organs. Tissue fibrosis is driven by activated fibroblasts (myofibroblasts) with exacerbated contractile and secretory properties. We previously reported that the long non-coding RNA HOTAIR is a key driver of SSc fibroblast activation. HOTAIR interacts with the chromatin modifiers, the polycomb repressor complex (PRC2) and coREST complex, promoting expression of pro-fibrotic genes. In this study, we show that acute activation of dermal fibroblasts from healthy subjects or SSc patients with transforming growth factor-β and other fibrotic stimuli requires the activity of the lysine-specific demethylase 1 (LSD1) subunit of the co-REST complex. Unexpectedly, LSD1 catalytic activity plays a minor role in fibrotic gene expression in HOTAIR-overexpressing fibroblasts and in maintenance of the stable myofibroblast phenotype of SSc fibroblasts. However, silencing of LSD1 in SSc fibroblasts has a profound effect on pro-fibrotic gene expression, supporting a non-canonical scaffolding function. Our study shows for the first time an essential non-canonical role for LSD1 in pro-fibrotic gene expression in SSc; however, given that this function is insensitive to LSD1 inhibitors, the therapeutic opportunities will depend on future identification of a targetable mediator.
Journal Article