A pH/Temperature-Sensitive s-IPN Based on Poly(vinyl alcohol), Poly(vinyl methyl ether-alt-maleic acid) and Poly(vinyl methyl ether) Prepared by Autoclaving

Karla F. García-Verdugo,Andya J. Ramírez-Irigoyen,Mónica Castillo-Ortega,Dora E. Rodríguez-Félix,Jesús M. Quiroz-Castillo,Judith Tánori-Córdova,Francisco Rodríguez-Félix,Antonio Ledezma-Pérez,Teresa d 한국고분자학회 2022 Macromolecular Research Vol.30 No.6

A novel semi-interpenetrating polymer network (s-IPN) based on the entrapment of a thermosensitive polymer, the poly(vinyl methyl ether) (PVME), within a crosslinked 3D structure of poly(vinyl alcohol) (PVA) and poly(vinyl methyl etheralt- maleic acid) (COP) was synthesized by an autoclaving process. The preparation method avoids the use of toxic crosslinkers and allows the simultaneous sterilization of material. The PVA/COP/PVME hydrogel were characterized by Fourier transform infrared spectroscopy, thermal techniques, swelling kinetic measurements, scanning electron microscopy, and rheological analysis. The entrapment of PVME within the hydrated polymer framework significantly modified its transition temperature at pH 7.4 and pH 3 conditions. The swelling kinetics of the s-IPN were dependent on pH (7.4, 3 and 1), and temperature (25 and 37℃). The interpenetrated polymer chains reduced the internal pore sizes of crosslinked network without altering its elastic, solid-like behavior. The loading and in vitro release of 5-fluorouracil, a chemotherapeutic agent, from hydrogel systems were studied at different temperature and pH values. The hydrogels showed a sustained drug release up to 5 h at 37℃, in different pH media. The s-IPN exhibited a promising performance for a range of biomedical applications, in particular, for the controlled drug delivery in response to the pH and temperature conditions.

Risk of Cognitive Impairment in Patients With Parkinson’s Disease With Visual Hallucinations and Subjective Cognitive Complaints

Diego Santos-García,Teresa de Deus Fonticoba,Carlos Cores Bartolomé,Maria J. Feal Painceiras,Jose M. Paz González,Cristina Martínez Miró,Silvia Jesús,Miquel Aguilar,Pau Pastor,Lluís Planellas,Marina C 대한신경과학회 2023 Journal of Clinical Neurology Vol.19 No.4

Background and Purpose Visual hallucinations (VH) and subjective cognitive complaints (SCC) are associated with cognitive impairment (CI) in Parkinson’s disease. Our aims were to determine the association between VH and SCC and the risk of CI development in a cohort of patients with Parkinson’s disease and normal cognition (PD-NC). Methods Patients with PD-NC (total score of >80 on the Parkinson’s Disease Cognitive Rating Scale [PD-CRS]) recruited from the Spanish COPPADIS cohort from January 2016 to November 2017 were followed up after 2 years. Subjects with a score of ≥1 on domain 5 and item 13 of the Non-Motor Symptoms Scale at baseline (V0) were considered as “with SCC” and “with VH,” respectively. CI at the 2-year follow-up (plus or minus 1 month) (V2) was defined as a PD-CRS total score of <81. Results At V0 (n=376, 58.2% males, age 61.14±8.73 years [mean±SD]), the frequencies of VH and SCC were 13.6% and 62.2%, respectively. VH were more frequent in patients with SCC than in those without: 18.8% (44/234) vs 4.9% (7/142), p<0.0001. At V2, 15.2% (57/376) of the patients had developed CI. VH presenting at V0 was associated with a higher risk of CI at V2 (odds ratio [OR]=2.68, 95% confidence interval=1.05–6.83, p=0.039) after controlling for the effects of age, disease duration, education, medication, motor and nonmotor status, mood, and PD-CRS total score at V0. Although SCC were not associated with CI at V2, presenting both VH and SCC at V0 increased the probability of having CI at V2 (OR=3.71, 95% confidence interval= 1.36–10.17, p=0.011). Conclusions VH were associated with the development of SCC and CI at the 2-year follow-up in patients with PD-NC.

Work Ability Index: Psychometric Testing in Aeronautical Industry Workers

González-Domínguez María Eugenia,Fernández-García Elena,Paloma-Castro Olga,González-López Regina María,Rivas Pérez María Paz,López-Molina Luis,García-Jiménez Jesús,Romero-Sánchez José Manuel 한국산업안전보건공단 산업안전보건연구원 2024 Safety and health at work Vol.15 No.1

Background The Work Ability Index (WAI) is an instrument that measures work ability. The wide dispersion of the WAI internationally has led to its adaptation for use in different countries. This study aimed to evaluate the psychometric properties of the Spanish version of the WAI. Methods A methodological design was used over an opportunistic sample of 233 workers in the aeronautical industry in Spain. Reliability was evaluated through internal consistency. Factorial validity, known groups, and convergent validity were tested. Results The Cronbach's alpha and item-total correlation indicated an adequate internal consistency. The confirmatory factor analysis, performed to evaluate the factorial validity, found adequate fit indices for a two-factor solution with a high correlation between the factors. Factor 1, “Subjectively estimated work ability and resources”, was composed of 3 subscales and factor 2, “Ill-health-related”, of 2 subscales. Subscales 4 and 6 had loading in both factors. Workers under 45 years of age obtained higher significant scores than older ones. Convergent validity was also evidenced since WAI was highly correlated with self-assessment of health status. Conclusions The Spanish version of the WAI has shown evidence of reliability and validity in this study, supporting its use in individual and collective health surveillance by occupational health professionals. The factorial solution that was found has previously been reported in another international context. However, further research is needed to resolve the discrepancies detected in the role of some subscales between other national and international studies. Background The Work Ability Index (WAI) is an instrument that measures work ability. The wide dispersion of the WAI internationally has led to its adaptation for use in different countries. This study aimed to evaluate the psychometric properties of the Spanish version of the WAI. Methods A methodological design was used over an opportunistic sample of 233 workers in the aeronautical industry in Spain. Reliability was evaluated through internal consistency. Factorial validity, known groups, and convergent validity were tested. Results The Cronbach's alpha and item-total correlation indicated an adequate internal consistency. The confirmatory factor analysis, performed to evaluate the factorial validity, found adequate fit indices for a two-factor solution with a high correlation between the factors. Factor 1, “Subjectively estimated work ability and resources”, was composed of 3 subscales and factor 2, “Ill-health-related”, of 2 subscales. Subscales 4 and 6 had loading in both factors. Workers under 45 years of age obtained higher significant scores than older ones. Convergent validity was also evidenced since WAI was highly correlated with self-assessment of health status. Conclusions The Spanish version of the WAI has shown evidence of reliability and validity in this study, supporting its use in individual and collective health surveillance by occupational health professionals. The factorial solution that was found has previously been reported in another international context. However, further research is needed to resolve the discrepancies detected in the role of some subscales between other national and international studies.

Identification of geometric parameters of a parallel robot by using a camera calibration technique

Mauricio Arredondo-Soto,Mario A. García-Murillo,J. Jesús Cervantes-Sánchez,Felipe J. Torres,Hector A. Moreno-Avalos 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.2

This work reports a novel method to estimate the geometrical parameters of a 2-(3-RRPS) parallel robot intended for manufacturing tasks. The method uses camera calibration techniques, and it is based on the concept of vertex space. The advantage of this technique is that the system does not require complex electronic instrumentation, and only uses a CCD camera as a main sensor and planar patterns, which makes it portable, accurate and low cost. To ensure the quality of the measurements, a methodology for characterization of the measurement system is included. The applicability and the advantages of using the proposed method are shown by means of the estimation of the geometrical dimensions of a spatial parallel manipulator with a relatively complex kinematic architecture. Experiments are conducted and show a significant improvement in manipulator accuracy when the parameters estimated with this technique are used.

Novel Sources of Resistance to Phytophthora capsici on Pepper (Capsicum sp.) Landraces from Mexico

Jesú,s Enrique Retes-Manjarrez,Walter Arturo Rubio-Aragó,n,Isidro Má,rques-Zequera,Isabel Cruz-Lachica,Raymundo Saú,l Garcí,a-Estrada,Ousmane Sy 한국식물병리학회 2020 Plant Pathology Journal Vol.36 No.6

Phytophthora capsici Leonian is a major pathogen of pepper worldwide and few resistance sources to this pathogen have been identified so far. The goals of this study were to identify new sources of resistance against P. capsici in Capsicum landraces and analyze the relationship between the resistance indicator of plant symptoms and some plant phenotype parameters of plant height, stem width, leaf length and leaf width. Thirtytwo landraces of pepper were collected from fourteen states in Mexico. From each population, 36 plants were inoculated with 10,000 zoospores of P. capsici under controlled conditions. This experiment was repeated twice. Out of the 32 landraces, six showed high level of resistance, four showed intermediate resistance and five showed low level of resistance when compared with the susceptible control ‘Bravo’ and the resistant control ‘CM334’, indicating that these landraces are promising novel sources of resistance to P. capsici. There was no correlation between the symptoms and plant phenotype parameters. However, these parameters were not affected in the group classified as highly resistant, indicating that P. capsici does not affect the growing of these resistant pepper landraces. The other resistant groups were significantly affected in a differently manner regarding their phenotype, indicating that this pathogen reduce their growth in different ways. This study reports novel resistance sources with great potential that could be used in breeding programs to develop new pepper cultivars with durable resistance to P. capsici.

Fluid-structure interaction of a tensile fabric structure subjected to different wind speeds

Jesús G. Valdés-Vázquez,Adrián D. García-Soto,Alejandro Hernández-Martínez,José L. Nava 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.31 No.6

Despite the current technologic developments, failures in existent tensile fabric structures (TFS) subjected to wind do happen. However, design pressure coefficients are only obtained for large projects. Moreover, studies on TFSs with realistic supporting frames, comparing static and dynamic analyses and discussing the design implications, are lacking. In this study, fluid-Structure analyses of a TFS supported by masts and inclined cables, by subjecting it to different wind speeds, are carried out, to gain more understanding in the above-referred aspects. Wind-induced stresses in the fabric and axial forces in masts and cables are assessed for a hypar by using computational fluid dynamics. Comparisons are carried out versus an equivalent static analysis and also versus loadings deemed representative for design. The procedure includes the so-called form-finding, a finite element formulation for the TFS and the fluid formulation. The selected structure is deemed realistic, since the supporting frame is included and the shape and geometry of the TFS are not uncommon. It is found that by carrying out an equivalent static analysis with the determined pressure coefficients, differences of up to 24% for stresses in the fabric, 5.4% for the compressive force in the masts and 21% for the tensile force in the cables are found with respect to results of the dynamic analysis. If wind loads commonly considered for design are used, significant differences are also found, specially for the reactions at the supporting frame. The results in this study can be used as an aid by designers and researchers.

The fire-risks of cost-optimized steel structures: Fire-resistant and hot-rolled carbon steel

Harkaitz García,Jesús Cuadrado,María V. Biezma,Iñigo Calderón 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.1

This work studies the behaviour of a steel portal frame selection under fire exposure, considering both span lengths and fire exposure times as variables. Such structures combine carbon steel (S275), fireproof micro-alloyed steel (FR), and coatings of intumescent paint with variable thicknesses, improving thereby the flame retardant behaviour of the steel structure. Thus, the main contribution of this study is the optimization of the portal frames by combining both steels, analysing the resulting costs influence on the final dimensions. Besides, the topological optimization of each steel component within the structure is also defined, in accordance with the following variables: weather conditions, span, paint thickness, and cost of steel. The results mainly confirmed that using both FR and S275 grades with intumescent painting is the Pareto optimum when considering performance, feasibility and costs of such portal frames widely used for industrial facilities.

Enzymatic browning and genome-wide polyphenol oxidase gene identification in three contrasting avocado accessions

Higuera-Rubio Jesús M.,Ibarra-Laclette Enrique,Reyes-López Miguel A.,Sandoval-Castro Eduardo,Cruz-Mendívil Abraham,Vega-García Misael O.,Calderón-Vázquez Carlos L. 한국식물생명공학회 2022 Plant biotechnology reports Vol.16 No.4

This study aims to disentangle avocado enzymatic browning by identifying and analyzing the PPO coding genes. Two avocado accessions (AVO48 and San Miguel) and the Hass cultivar with contrasting browning kinetics and enzyme activity levels were selected for gene characterization. Upon 90 min of light exposure, Hass and San Miguel showed a greater decrease in luminosity retention (closer to 40% of initial luminosity) compared to AVO48 (85% of luminosity). PPO activity in crude extracts was significantly higher (P < 0.05) in San Miguel (696 U μg-1 protein) than Hass (174 U μg-1 protein) and AVO48 (46–56 U μg-1 protein). San Miguel showed a higher Vmax Km-1 ratio (20.88 min-1), followed by Hass (14.29 min-1) and AVO48 (1.64 min-1), suggesting that San Miguel and Hass have higher substrate affinity. Four PPO coding genes: PamPPO1, PamPPO2, PamPPO3 and PamPPO4 were identified in the Hass genome, all of them containing the main features of plant PPOs, but with specific amino acid combinations in the catalytic pocket of the tyrosinase domain; suggesting that PPO1, PPO2 and PPO4 have monophenolase activity, whereas PPO3, has o-diphenolase activity. The evidence of transcription of PPO3 in fruit of the three genotypes suggests an important role for this gene in avocado pulp browning. PPO2 expression was only found in AVO48. This research provides gene candidates for selective silencing to reduce enzymatic browning.

Diagnostic Yield and Therapeutic Impact of Rectal Retroflexion: A Prospective, Single-Blind Study Conducted in Three Centers

Félix Téllez-Ávila,Josué Barahona-Garrido,Sandra García-Osogobio,Gustavo López-Arce,Jesús Camacho-Escobedo,Angela Saúl,Salvador Herrera-Gómez,Javier Elizondo-Rivera,Rafael Barreto-Zúñiga 대한소화기내시경학회 2014 Clinical Endoscopy Vol.47 No.1

Background/Aims: No clear data have been established and validated regarding whether rectal retroflexion has an important and therapeutic impact. The aim of the present study was to evaluate the diagnostic yield and therapeutic impact of rectal retroflexion compared with straight view examination. Methods: A prospective single-blind study was conducted. Consecutive patients evaluated between October 2011 and April 2012 were included. Results: A total of 934 patients (542 women [58%]) were included. The mean age was 57.4±14.8 years. Retroflexion was successful in 917 patients (98.2%). Distinct lesions in the anorectal area were detected in 32 patients (3.4%), of which 10 (1%) were identified only on retroflex view and 22 (2.4%) on both straight and retroflex views. Of the 32 identified lesions, 16 (50%) were polyps, nine (28.1%) were angiodysplasias, six (18.8%) were ulcers, and one (3.1%) was a flat lesion. All 10 patients (1%) in whom lesions were detected only by rectal retroflexion showed a therapeutic impact. Conclusions: Rectal retroflexion has minimal diagnostic yield and therapeutic impact. However, its low rate of major complications and the possibility of detecting lesions undetectable by straight viewing justify its use.

Homozygous LPL p.Gly188Glu Mutation in a Mexican Girl With Lipoprotein Lipase Deficiency

Ana Gabriela Colima Fausto,Juan Ramón González García,Teresita De Jesús Hernández Flores,Norma Alejandra Vázquez Cárdenas,Nery Eduardo Solís Perales,María Teresa Magaña Torres 대한진단검사의학회 2017 Annals of Laboratory Medicine Vol.37 No.4

Dear Editor, Lipoprotein lipase (LPL) deficiency is a rare disease characterized by severe hypertriglyceridemia due to mutations in the LPL gene. It shows an autosomal recessive inheritance pattern and has a general prevalence of 1:1,000,000 [1]. Patients typically present abdominal pain, hemorrhage, failure to thrive, jaundice, eruptive xanthomas, lipemia retinalis, neurological complications, hepatosplenomegaly, and life-threatening pancreatitis [2]. The LPL gene is located on chromosomal band 8p22, contains 10 exons, and codes for a 475-amino acid protein that is active only in its dimeric form. The LPL protein has two functions in lipid metabolism: it hydrolyzes triglycerides and functions as a ligand [3]. The aim of this work is to describe the biochemical, clinical, and molecular features of a Mexican girl with LPL deficiency.