9 results on '"Márquez, G."'
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2. Degradation of Methylparaben Using Optimal WO 3 Nanostructures: Influence of the Annealing Conditions and Complexing Agent.
- Author
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Cifre-Herrando, M., Roselló-Márquez, G., García-García, D. M., and García-Antón, J.
- Subjects
- *
PHOTOELECTROCHEMISTRY , *LIQUID chromatography-mass spectrometry , *FIELD emission electron microscopes , *X-ray photoelectron spectroscopy , *NANOSTRUCTURES , *X-ray lasers - Abstract
In this work, WO3 nanostructures were synthesized with different complexing agents (0.05 M H2O2 and 0.1 M citric acid) and annealing conditions (400 °C, 500 °C and 600 °C) to obtain optimal WO3 nanostructures to use them as a photoanode in the photoelectrochemical (PEC) degradation of an endocrine disruptor chemical. These nanostructures were studied morphologically by a field emission scanning electron microscope. X-ray photoelectron spectroscopy was performed to provide information of the electronic states of the nanostructures. The crystallinity of the samples was observed by a confocal Raman laser microscope and X-ray diffraction. Furthermore, photoelectrochemical measurements (photostability, photoelectrochemical impedance spectroscopy, Mott–Schottky and water-splitting test) were also performed using a solar simulator with AM 1.5 conditions at 100 mW·cm−2. Once the optimal nanostructure was obtained (citric acid 0.01 M at an annealing temperature of 600 °C), the PEC degradation of methylparaben (CO 10 ppm) was carried out. It was followed by ultra-high-performance liquid chromatography and mass spectrometry, which allowed to obtain the concentration of the contaminant during degradation and the identification of degradation intermediates. The optimized nanostructure was proved to be an efficient photocatalyst since the degradation of methylparaben was performed in less than 4 h and the kinetic coefficient of degradation was 0.02 min−1. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Electrophysiological Characterization of Cerebellar Responses during Exploration and Grooming Behaviors in a Rat Model of Parkinsonism.
- Author
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Vásquez-Celaya L, Marín-Márquez G, Manzo J, Carrillo-Castilla P, Martínez AJ, Ortiz Pulido R, Zempoalteca Ramírez R, Coria-Avila GA, and García LI
- Abstract
Parkinson's disease is currently a global public health challenge due to the rapid growth of aging populations. To understand its pathophysiology is necessary to study the functional correlation between the basal ganglia (BG) and the cerebellum, which are involved in motor control. Herein, we explored multiunit electrical activity (MUA) in the cerebellum of rats with induced Parkinsonism as a result of lesions following bilateral placement of electrodes and passing of current in the ventrolateral striatum (VLS). In one control group, the electrodes descended without electrical current, and another group was left intact in VLS. MUA was recorded in Sim B and Crus II lobes, and in the dentate nucleus (DN) during the execution of exploration behaviors (horizontal and vertical) and grooming. The lesioned and sham groups showed a decrease in MUA amplitude in the Crus II lobe compared to the intact group in all recorded behaviors. However, Sim B and DN did not express differences. Both electrical and physical insults to the VLS induced Parkinsonism, which results in less MUA in Crus II during the execution of motor behaviors. Thus, this type of Parkinsonism is associated with a decrease in the amplitude of Crus II.
- Published
- 2023
- Full Text
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4. Barriers and Facilitators of Ambient Assisted Living Systems: A Systematic Literature Review.
- Author
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Márquez G and Taramasco C
- Subjects
- Humans, Aged, Patients, Quality of Life, Ambient Intelligence
- Abstract
Ambient Assisted Living Systems (AALSs) use information and communication technologies to support care for the growing population of older adults. AALSs focus on providing multidimensional support to families, primary care facilities, and patients to improve the quality of life of the elderly. The literature has studied the qualities of AALSs from different perspectives; however, there has been little discussion regarding the operational experience of developing and deploying such systems. This paper presents a literature review based on the PRISMA methodology regarding operational facilitators and barriers of AALSs. This study identified 750 papers, of which 61 were selected. The results indicated that the selected studies mentioned more barriers than facilitators. Both barriers and facilitators concentrate on aspects of developing and configuring the technological infrastructure of AALSs. This study organizes and describes the current literature on the challenges and opportunities regarding the operation of AALSs in practice, which translates into support for practitioners when developing and deploying AALSs.
- Published
- 2023
- Full Text
- View/download PDF
5. Detection of COVID-19 Patients Using Machine Learning Techniques: A Nationwide Chilean Study.
- Author
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Ormeño P, Márquez G, Guerrero-Nancuante C, and Taramasco C
- Subjects
- Chile epidemiology, Humans, Machine Learning, Pandemics, Support Vector Machine, COVID-19 epidemiology
- Abstract
Epivigila is a Chilean integrated epidemiological surveillance system with more than 17,000,000 Chilean patient records, making it an essential and unique source of information for the quantitative and qualitative analysis of the COVID-19 pandemic in Chile. Nevertheless, given the extensive volume of data controlled by Epivigila, it is difficult for health professionals to classify vast volumes of data to determine which symptoms and comorbidities are related to infected patients. This paper aims to compare machine learning techniques (such as support-vector machine, decision tree and random forest techniques) to determine whether a patient has COVID-19 or not based on the symptoms and comorbidities reported by Epivigila. From the group of patients with COVID-19, we selected a sample of 10% confirmed patients to execute and evaluate the techniques. We used precision, recall, accuracy, F1-score, and AUC to compare the techniques. The results suggest that the support-vector machine performs better than decision tree and random forest regarding the recall, accuracy, F1-score, and AUC. Machine learning techniques help process and classify large volumes of data more efficiently and effectively, speeding up healthcare decision making.
- Published
- 2022
- Full Text
- View/download PDF
6. Does Heavy-Resistance Training Improve Mobility and Perception of Quality of Life in Older Women?
- Author
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Borges-Silva F, Martínez-Pascual M, Colomer-Poveda D, Márquez G, and Romero-Arenas S
- Abstract
Regular physical exercise has shown great benefits in preventing age-related functional losses and in improving the perception of health-related quality of life (HRQoL) in older people. To optimize these benefits, it would be interesting to evaluate what type of exercise is better. Therefore, the purpose of this study was to assess the effects of heavy-resistance training on mobility and HRQoL in older women. Forty healthy, untrained older women (60−75 years) were randomly assigned to three groups: circuit resistance training (CRT, n = 15), traditional resistance training (TRT, n = 15) or the control group (CG, n = 10). During the 12-week training period, both experimental groups performed training with heavy loads, twice a week. Before and after the training period, the Timed Up and Go test, as a proxy of mobility, and the perception of HRQoL were evaluated. TRT and CRT resulted in a statistically significant improvement in the Timed Up and Go test (−5.4 and −10.3%, respectively; p < 0.05), but only the improvement after CRT was significantly greater than changes in the CG (p < 0.001). Only CRT elicited improvements in several dimensions of the perception of the HRQoL questionnaire, such as: physical functioning (13%, p < 0.001), general health (8.1%; p = 0.048), vitality (17.7%; p < 0.001), role emotional (6.7%; p = 0.044) and physical component summary (6.3%; p = 0.001). The change in the CRT group was greater than in the CG (p < 0.001) in the physical functioning score. The present findings show that CRT might be a time- (and hence cost-) effective alternative to trigger multiple positive functional and psychological adaptations in older women.
- Published
- 2022
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7. Using Low-Resolution Non-Invasive Infrared Sensors to Classify Activities and Falls in Older Adults.
- Author
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Márquez G, Veloz A, Minonzio JG, Reyes C, Calvo E, and Taramasco C
- Subjects
- Aged, Aging, Gait, Humans, Privacy, Accidental Falls prevention & control, Quality of Life
- Abstract
The population is aging worldwide, creating new challenges to the quality of life of older adults and their families. Falls are an increasing, but not inevitable, threat to older adults. Information technologies provide several solutions to address falls, but smart homes and the most available solutions require expensive and invasive infrastructures. In this study, we propose a novel approach to classify and detect falls of older adults in their homes through low-resolution infrared sensors that are affordable, non-intrusive, do not disturb privacy, and are more acceptable to older adults. Using data collected between 2019 and 2020 with the eHomeseniors platform, we determine activity scores of older adults moving across two rooms in a house and represent an older adult fall through skeletonization. We find that our twofold approach effectively detects activity patterns and precisely identifies falls. Our study provides insights to physicians about the daily activities of their older adults and could potentially help them make decisions in case of abnormal behavior.
- Published
- 2022
- Full Text
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8. Classical Biomarker and Quantitative Extended Diamondoid Analysis Fingerprints for Crude Oils from Deepwater Developments in Block 17, Lower Congo Basin, Angola.
- Author
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Boente C, Márquez G, Marín P, Romero E, Rodrigues C, and Guzmán MA
- Subjects
- Angola, Congo, Biodegradation, Environmental, Biomarkers, Petroleum
- Abstract
The organic geochemistry of six oil samples from the offshore Block 17 (Lower Congo Basin, northwestern Angola) was studied by a combination of classical biomarker and extended diamondoid analyses to elucidate source rock facies, the extent of biodegradation, and thermal maturity. Based on molecular data, oils are interpreted as depicting a mixture of two pulses of hydrocarbon generation probably from the Bucomazi and Malembo formations. Geochemical results also gave evidence of mixing of a lacustrine siliciclastic-sourced oil charge and a second more terrestrially derived oil type in the samples analyzed. A single genetic oil family was identified through hierarchical cluster analysis; however, two groups of oils were identified on the basis of their biodegradation levels using the Peters/Moldowan scale. Lower and upper Malembo oils have a slight depletion and a notable absence of n -alkanes, suggesting PM levels of 1 and 2, respectively. Most molecular maturity parameters of the oil samples suggest a maturity level equivalent to the onset of the peak of the oil generative window., Competing Interests: The authors declare no conflict of interest.
- Published
- 2020
- Full Text
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9. Physicochemical and Antimicrobial Characterization of Beeswax-Starch Food-Grade Nanoemulsions Incorporating Natural Antimicrobials.
- Author
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Arredondo-Ochoa T, García-Almendárez BE, Escamilla-García M, Martín-Belloso O, Rossi-Márquez G, Medina-Torres L, and Regalado-González C
- Subjects
- Anti-Infective Agents chemistry, Emulsions chemistry, Emulsions therapeutic use, Hexoses chemistry, Hexoses therapeutic use, Humans, Nanocomposites therapeutic use, Polysorbates chemistry, Polysorbates therapeutic use, Starch chemistry, Starch therapeutic use, Stearic Acids chemistry, Stearic Acids therapeutic use, Anti-Infective Agents therapeutic use, Drug Delivery Systems, Nanocomposites chemistry, Waxes chemistry
- Abstract
Nanoemulsions are feasible delivery systems of lipophilic compounds, showing potential as edible coatings with enhanced functional properties. The aim of this work was to study the effect of emulsifier type (stearic acid (SA), Tween 80 (T80) or Tween 80/Span 60 (T80/S60)) and emulsification process (homogenization, ultrasound or microfluidization) on nanoemulsion formation based on oxidized corn starch, beeswax (BW) and natural antimicrobials (lauric arginate and natamycin). The response variables were physicochemical properties, rheological behavior, wettability and antimicrobial activity of BW-starch nanoemulsions (BW-SN). The BW-SN emulsified using T80 and microfluidized showed the lowest droplet size (77.6 ± 6.2 nm), a polydispersion index of 0.4 ± 0.0 and whiteness index (WI) of 31.8 ± 0.8. This BW-SN exhibited a more negative ζ-potential: -36 ± 4 mV, and Newtonian flow behavior, indicating great stability. BW-SN antimicrobial activity was not affected by microfluidization nor the presence of T80, showing inhibition of the deteriorative fungi R. stolonifer , C. gloeosporioides and B. cinerea , and the pathogenic bacterium S. Saintpaul. In addition, regardless of emulsifier type and emulsification process, BW-SN applied on the tomato surface exhibited low contact angles (38.5° to 48.6°), resulting in efficient wettability (-7.0 mN/m to -8.9 mN/m). These nanoemulsions may be useful to produce edible coatings to preserve fresh-produce quality and safety., Competing Interests: The authors declare that there is not conflict of interests regarding the publication of this paper.
- Published
- 2017
- Full Text
- View/download PDF
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