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1.
Materials (Basel) ; 17(3)2024 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-38591472

RESUMO

Piezoelectric cement-based composites could serve to monitor the strain state of structural elements or act as self-powered materials in structural health monitoring (SHM) applications. The incorporation of piezoelectric materials as an active phase within cement matrices has presented a highly attractive avenue until today. However, their application is challenged by the low electrical conductivity of the hydrated cement matrix. Gold nanoparticles (Au NPs) possess substantial potential for elevating the free electrical charge within the matrix, increasing its electrical conductivity between the Au NPs and the cement matrix, thereby enhancing the piezoelectric response of the composite. In this sense, the objective of this study is to investigate the effects of incorporating low concentrations of gold nanoparticles (Au NPs) (442 and 658 ppm) on the electrical and piezoelectric properties of cement-based composites. Additionally, this study considers the effects of such properties when the material is cured under a constant electric field. Electrical impedance spectroscopy was used to evaluate the polarization resistance and piezoresistive properties of the material. Additionally, open-circuit potential measurements were taken alongside the application of mechanical loads to assess the piezoelectric activity of the composites. The findings revealed a notable decrease in the composite's total electrical resistance, reaching a value of 1.5 ± 0.2 kΩ, almost four times lower than the reference specimens. In the realm of piezoelectricity, the piezoelectric voltage parameter g33 exhibited a remarkable advancement, improving by a factor of 57 when compared to reference specimens. This significant enhancement can be attributed to both the concentration of Au NPs and the electrical curing process. In summary, the outcomes of this study underscore the feasibility of creating a highly electrically conductive cement-based matrix, using low concentrations of gold nanoparticles as electric charge carries, and indicate the possible piezoelectric behavior of the studied compposite.

2.
PNAS Nexus ; 2(11): pgad361, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38034093

RESUMO

A sustainable low-carbon transition via electric vehicles will require a comprehensive understanding of lithium-ion batteries' global supply chain environmental impacts. Here, we analyze the cradle-to-gate energy use and greenhouse gas emissions of current and future nickel-manganese-cobalt and lithium-iron-phosphate battery technologies. We consider existing battery supply chains and future electricity grid decarbonization prospects for countries involved in material mining and battery production. Currently, around two-thirds of the total global emissions associated with battery production are highly concentrated in three countries as follows: China (45%), Indonesia (13%), and Australia (9%). On a unit basis, projected electricity grid decarbonization could reduce emissions of future battery production by up to 38% by 2050. An aggressive electric vehicle uptake scenario could result in cumulative emissions of 8.1 GtCO2eq by 2050 due to the manufacturing of nickel-based chemistries. However, a switch to lithium iron phosphate-based chemistry could enable emission savings of about 1.5 GtCO2eq. Secondary materials, via recycling, can help reduce primary supply requirements and alleviate the environmental burdens associated with the extraction and processing of materials from primary sources, where direct recycling offers the lowest impacts, followed by hydrometallurgical and pyrometallurgical, reducing greenhouse gas emissions by 61, 51, and 17%, respectively. This study can inform global and regional clean energy strategies to boost technology innovations, decarbonize the electricity grid, and optimize the global supply chain toward a net-zero future.

3.
MethodsX ; 11: 102280, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37448953

RESUMO

Nowadays, cement industry researchers are working hard to develop cement sensors based on nanocomposites because they can be used to develop intelligent and sustainable civil structures, self-powered, self-healing, or self-monitoring. In this light, this paper shows a methodology to obtain piezoelectric cement sensors, which produce enough energy not to require an external power source in sensing-strain applications. Mainly, two proposed experimental procedures increased the piezoelectric properties of these cement-based composites: add gold nanoparticles in the proper concentrations and apply a constant electric field during the curing stage. Firstly, the gold nanoparticles were obtained through a pulsed laser ablation system, and their particle size distribution was measured with a particle analyzer Litesizer 500 from Anton Paar, and their morphology was corroborated using a scanning electron microscope. Two concentrations (442 ppm and 658 ppm) of gold nanoparticles were obtained by changing the total ablation time. Next, we fabricated the cement sensors as described by ASTM standards C39-C39M. Hence, the cement was hand mixed with a water-to-cement ratio (w/c) of 0.47 for then poured on cylindrical molds saving the proportions recommended by the ASTM standard; in this stage, the gold nanoparticles were already part of the water ratio. Then, the cement sensors were cured under an external electric field and dried for 24 hours more in an oven to be finally ready for electromechanical characterization. Meanwhile, the electric response in altern current and the piezoelectric behavior were corroborated through electrical impedance spectroscopy and open circuit potential measurements, respectively. The piezoelectric behavior was obtained when a compressive strength was applied to the sensor, and the generated voltage was simultaneously measured. Finally, the electrical and mechanical characterization measurements were processed and analyzed using Python scripts.•The particle size and the families amount of Au NPs are affected by the ablation time.•The correct proportion of Au NPs increases the inherent piezoelectricity of cement paste.•The piezoelectric response can be addressed by coupling electric and mechanical tests.

4.
Arch. cardiol. Méx ; 93(2): 223-232, Apr.-Jun. 2023. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1447254

RESUMO

Resumen Esta guía propone brindar una ayuda a todos los médicos para la identificación metódica de cada marca comercial de marcapasos por radiografía simple de tórax, por medio de sus componentes electrónicos (conectores de electrodos, circuito lógico y batería), siendo necesario para la interrogación de dispositivos de marcapasos posterior a su implante. Se describirán los diferentes tipos de marcapasos, electrodos y modos de programación más frecuentemente utilizados.


Abstract This guide provides help for medical doctors systematically identifying each commercial brand of pacemakers by thoracic radiography through their electronic components (electrode connectors, logic circuit, and battery); this is crucial for watching the pacemaker after being implanted. We aimed to describe the different cardiac stimulation devices, electrodes, and programming modes more frequently used.

5.
Arch Cardiol Mex ; 93(2): 223-232, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37037220

RESUMO

This guide provides help for medical doctors systematically identifying each commercial brand of pacemakers by thoracic radiography through their electronic components (electrode connectors, logic circuit, and battery); this is crucial for watching the pacemaker after being implanted. We aimed to describe the different cardiac stimulation devices, electrodes, and programming modes more frequently used.


Esta guía propone brindar una ayuda a todos los médicos para la identificación metódica de cada marca comercial de marcapasos por radiografía simple de tórax, por medio de sus componentes electrónicos (conectores de electrodos, circuito lógico y batería), siendo necesario para la interrogación de dispositivos de marcapasos posterior a su implante. Se describirán los diferentes tipos de marcapasos, electrodos y modos de programación más frecuentemente utilizados.


Assuntos
Arritmias Cardíacas , Marca-Passo Artificial , Humanos , Estimulação Cardíaca Artificial , Coração , Sistema de Registros
6.
Polymers (Basel) ; 15(4)2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36850252

RESUMO

This work reports the synthesis, characterization, and in vitro release studies of pH- and temperature-sensitive Fe3O4-SiO2-poly(NVCL-co-MAA) nanocomposite. Fe3O4 nanoparticles were prepared by chemical coprecipitation, coated with SiO2 by the Stöber method, and functionalized with vinyl groups. The copolymer poly(N-vinylcaprolactam-co-methacrylic acid) (poly(NVCL-co-MAA)) was grafted onto the functionalized Fe3O4-SiO2 nanoparticles by free radical polymerization. XRD, FTIR, TGA, VSM, and TEM techniques were performed to characterize the nanocomposite. The release behavior of Doxorubicin (DOX) loaded in the nanocomposite at pH 5.8 and 7.4, and two temperatures, 25 and 37 °C, was studied. According to the release studies, approximately 55% of DOX is released in 72 h at pH 7.4, regardless of temperature. At pH 5.8, 78% of DOX was released in 48 h at 25 °C, and when increasing the temperature to 37 °C, more than 95 % of DOX was released in 24 h. The DOX release data treated with Zero-order, first-order, Higuchi, and Korsmeyer-Peppas models showed that Higuchi's model best fits the data, indicating that the DOX is released by diffusion. The findings suggest that the synthesized nanocomposite may be useful as a DOX carrier in biomedical applications.

7.
Front Psychol ; 13: 1018176, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36533029

RESUMO

Background: Cognitive impairment is frequent among people living with Parkinson's disease: up to 40% of patients exhibit symptoms of mild cognitive impairment and 25% meet the criteria for dementia. Parkinson's Disease Cognitive Rating Scale (PD-CRS) is one of the recommended scales by the Movement Disorders Society Task Force for level 1 screening of dementia. However, its psychometric properties have not been studied in the Colombian population. Methods: A cross-sectional study was conducted on 100 patients with Parkinson's disease diagnosed by a movement disorders neurologist. Patients were evaluated with PD-CRS and MoCA. Principal component analysis was conducted, and then confirmatory factor analysis was implemented through the maximum-likelihood method. Internal consistency was evaluated using Cronbach α. Convergent and divergent validity were also calculated and concurrent validity with the MoCA was assessed. Results: 62% were males. Their median age was 68 years (IQR 57-74) and the median disease duration was 4 years (IQR 2-9). 77% were classified in early stages (Hoehn and Yahr stage ≤ 2), while the MDS-UPDRS part III score was 25 (IQR 15.5-38). In the principal component factor analysis, the pattern matrix unveiled a mnesic and a non-mnesic domain. Confirmatory factor analysis showed similar explanatory capacity (λ ≥ 0.50) for items other than naming (λ = 0.34). Cronbach's α for the full 9-items instrument was 0.74. MoCA and PD-CRS total scores were correlated (ρ = 0.71, p = 0.000). Assuming a cut-off score of 62 points, there is an agreement of 89% with the definition of dementia by MoCA for Colombia (κ = 0.59; p = 0.000). Conclusion: PD-CRS has acceptable psychometric properties for the Colombian population and has significant correlation and agreement with a validated scale (MoCA).

8.
Front Hum Neurosci ; 16: 826376, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35664343

RESUMO

Introduction: The assessments of the motor symptoms in Parkinson's disease (PD) are usually limited to clinical rating scales (MDS UPDRS III), and it depends on the clinician's experience. This study aims to propose a machine learning technique algorithm using the variables from upper and lower limbs, to classify people with PD from healthy people, using data from a portable low-cost device (RGB-D camera). And can be used to support the diagnosis and follow-up of patients in developing countries and remote areas. Methods: We used Kinect®eMotion system to capture the spatiotemporal gait data from 30 patients with PD and 30 healthy age-matched controls in three walking trials. First, a correlation matrix was made using the variables of upper and lower limbs. After this, we applied a backward feature selection model using R and Python to determine the most relevant variables. Three further analyses were done using variables selected from backward feature selection model (Dataset A), movement disorders specialist (Dataset B), and all the variables from the dataset (Dataset C). We ran seven machine learning models for each model. Dataset was divided 80% for algorithm training and 20% for evaluation. Finally, a causal inference model (CIM) using the DoWhy library was performed on Dataset B due to its accuracy and simplicity. Results: The Random Forest model is the most accurate for all three variable Datasets (Dataset A: 81.8%; Dataset B: 83.6%; Dataset C: 84.5%) followed by the support vector machine. The CIM shows a relation between leg variables and the arms swing asymmetry (ASA) and a proportional relationship between ASA and the diagnosis of PD with a robust estimator (1,537). Conclusions: Machine learning techniques based on objective measures using portable low-cost devices (Kinect®eMotion) are useful and accurate to classify patients with Parkinson's disease. This method can be used to evaluate patients remotely and help clinicians make decisions regarding follow-up and treatment.

9.
eNeurologicalSci ; 27: 100407, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35669231

RESUMO

During a social evaluation, the right temporo-parietal junction (rTPJ) plays an important role according to its contribution in making inferences about the mental states of others. However, what is the neural response if rTPJ function is inhibited during a mentalizing task? In this study, participants played the Dictator Game with two confederates: one playing cooperation (C) and other playing non-cooperation (NC) role and then they were scanned during a mentalizing test. However, we inhibited rTPJ using transcranial magnetic stimulation (TMS) after they played the game and before they were scanned. In this test, participants read negative (Neg) or positive (Pos) personal situations and then they watched confederate's pictures. Images from the TMS group were compared against controls with no TMS stimulation. After statistical comparison, we found a significantly higher activity in right and left visual association areas (BA 18) during the NCPos > NCNeg condition in the TMS group compared with the No-TMS group. Same visual association areas have been described before when participants are processing visual emotional information or when making a fast social categorization. This could reflect a neural mechanism of socio - emotional categorization that emerges after rTPJ inhibition.

10.
PLoS Negl Trop Dis ; 16(6): e0009876, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35666764

RESUMO

Leptospirosis is among the most important zoonotic diseases in (sub-)tropical countries. The research objective was to evaluate the accuracy of the Serion IgM ELISA EST125M against the Microscopic Agglutination Test (MAT = imperfect reference test); to assess its ability to diagnose acute leptospirosis infections and to detect previous exposure to leptospires in an endemic setting. In addition, to estimate the overall Leptospira spp. seroprevalence in the Wiwa indigenous population in North-East Colombia. We analysed serum samples from confirmed leptospirosis patients from the Netherlands (N = 14), blood donor sera from Switzerland (N = 20), and sera from a cross-sectional study in Colombia (N = 321). All leptospirosis ELISA-positive, and a random of negative samples from Colombia were tested by the MAT for confirmation. The ELISA performed with a sensitivity of 100% (95% CI 77% - 100%) and a specificity of 100% (95% CI 83% - 100%) based on MAT confirmed Leptospira spp. positive and negative samples. In the cross-sectional study in Colombia, the ELISA performed with a sensitivity of 100% (95% CI 2-100%) and a specificity of 21% (95% CI 15-28%). Assuming a 5% Leptospira spp. seroprevalence in this population, the positive predictive value was 6% and the negative predictive value 100%. The Leptospira spp. seroprevalence in the Wiwas tested by the ELISA was 39%; however, by MAT only 0.3%. The ELISA is suitable to diagnose leptospirosis in acutely ill patients in Europe several days after onset of disease. For cross-sectional studies it is not recommended due to its low specificity. Despite the evidence of a high leptospirosis prevalence in other study areas and populations in Colombia, the Wiwa do not seem to be highly exposed to Leptospira spp.. Nevertheless, leptospirosis should be considered and tested in patients presenting with febrile illness.


Assuntos
Leptospira , Leptospirose , Testes de Aglutinação , Anticorpos Antibacterianos , Colômbia/epidemiologia , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina M , Povos Indígenas , Leptospirose/diagnóstico , Leptospirose/epidemiologia , Sensibilidade e Especificidade , Estudos Soroepidemiológicos
11.
Rev. colomb. cardiol ; 29(1): 36-40, ene.-feb. 2022. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1376852

RESUMO

Resumen Introducción: Las alteraciones secundarias a la enfermedad renal crónica (ERC), como inflamación sistémica, anemia y sobrecarga hídrica, son un sustrato importante para el desarrollo de hipertensión arterial pulmonar. Objetivo: Valorar la relación de la presión sistólica de la arteria pulmonar (PSAP) por ecocardiograma con el tiempo y el tipo de terapia de reemplazo renal (TRR) en pacientes con ERC. Método: Estudio observacional, retrospectivo, llevado a cabo en el Hospital de Especialidades del Centro Médico Nacional La Raza, en el que se analizaron medidas de tendencia central y medidas de dispersión. Para comparar porcentajes se utilizó la prueba de χ2 con el programa estadístico SPSS 25. Resultados: Se incluyeron 141 pacientes con ERC en TRR con diálisis peritoneal o hemodiálisis. Se clasificaron de acuerdo con la PSAP en normal (30 pacientes, 21.28%), leve (43 pacientes, 30.5%), moderada (16 pacientes, 12%) y grave (52 pacientes, 36.88%). El tiempo de TRR está relacionado con una PSAP mayor, con 3.53 años en caso de PSAP normal, 5.51 años en caso de PSAP leve, 6.00 años para la PSAP moderada y 6.38 años para la PSAP grave. La PSAP grave se presentó en 13 de 56 pacientes en diálisis peritoneal y en 39 de 85 en hemodiálisis (p = 0.034). Conclusiones: Se encontró que existe relación entre la PSAP con el tiempo y el tipo de sustitución renal en pacientes con ERC.


Abstract Introduction: The disorders secondary to chronic kidney disease (CKD), such as systemic inflammation, anemia, and fluid overload are an important substrate for the development of pulmonary arterial hypertension. Objective: To assess the relationship between pulmonary artery systolic pressure (PASP) on echocardiogram and the duration and type of renal replacement therapy (RRT) in patients with CKD. Method: A retrospective observational study at Hospital de Especialidades del Centro Médico Nacional La Raza. The analysis was performed using measures of central tendency and dispersion. Chi square was used to compare percentages through the SPSS 25 statistical program. Results: A total of 141 patients with CKD on RRT with peritoneal dialysis or hemodialysis were included. They were classified according to PASP as normal (30 patients, 21.28%), mild (43 patients, 30.5%), moderate (16 patients, 12%) and severe (52 patients, 36.88%). The duration of RRT is related to a higher PASP, with 3.53 years for a normal PASP, 5.51 years for mild PASP, 6.00 years for moderate PASP, and 6.38 for those with severe PASP. Severe PASP occurred in 13 of 56 patients on peritoneal dialysis and 39 of 85 patients on hemodialysis (p = 0.034). Conclusions: This study found a relationship between PASP and the duration and type of renal replacement in patients with CKD.

12.
Int J Biol Macromol ; 198: 119-127, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34963627

RESUMO

Cotton gauzes were grafted with a hydrogel of maltodextrin (MD) and poly(acrylic acid) (PAAc) using N-maleyl chitosan as crosslinker to obtain materials with antimicrobial properties. Reaction parameters including monomer, crosslinker, and initiator concentrations were studied. The modification with the copolymer poly(acrylic acid)-co-maltodextrin (PAAc-co-MD) was corroborated by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The grafted gauzes (gauze-g-(PAAc-co-MD)) were able to load vancomycin and inhibit the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. In addition, the incorporation of chitosan as crosslinker showed a synergistic effect against these bacteria. The prepared gauze-g-(PAAc-co-MD) materials could be used in the biomedical area particularly as antimicrobial wound dressings.


Assuntos
Quitosana
13.
Rev. cuba. oftalmol ; 34(4)dic. 2021.
Artigo em Espanhol | LILACS, CUMED | ID: biblio-1409021

RESUMO

Las arrugas son surcos o pliegues en la piel, que aparecen principalmente por efecto del envejecimiento. Este artículo describe el caso de un paciente masculino de 47 años de edad, piel blanca, que acudió a consulta de cirugía plástica ocular por inconformidad con el aspecto envejecido de su rostro a causa de las arrugas perioculares. Se le aplicó plasma rico en plaquetas intradérmico en el trayecto de las arrugas a razón de 3 dosis con intervalo promedio de 30 días entre cada una. Se logró la corrección total de las arrugas, con buenos resultados estéticos. No se encontró reacción adversa. Se reafirma el criterio planteado por estudios de que el plasma rico en plaquetas es una opción terapéutica de primera línea para rejuvenecer la región periocular(AU)


Wrinkles are a creases or folds which appear in the skin mainly as a result of aging. A case is described of a male 47-year-old patient of white skin color who attended ocular plastic surgery consultation for dissatisfaction with the periocular wrinkles on his face, which gave it an aged appearance. Intradermal platelet-rich plasma was applied along the course of the wrinkles at three doses with an average separation of 30 days between them. Total wrinkle correction was achieved, with good esthetic results. There was not any adverse reaction. The case confirms the criterion contained in previous studies that platelet-rich plasma is a first-line therapeutic option to rejuvenate the periocular region(AU)


Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Envelhecimento da Pele , Medicina Regenerativa/métodos , Plasma Rico em Plaquetas , Mesoterapia/métodos , Cirurgia Plástica
14.
Front Psychol ; 12: 782754, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35153905

RESUMO

This paper shows the brain correlates of Cloninger's personality model during the presentation of social scenarios under positive or negative valence situations. Social scenarios were constructed when participants played the Dictator game with two confederates that had two opposites roles as the cooperator (Coop) and non-cooperator (NoCoop). Later the same day during a fMRI scanning session, participants read negative (Neg) and positive (Pos) situations that happened to confederates in the past. Participants were asked to think "how do you think those people felt during that situation?" A dissimilarity matrix between stimuli were obtained from fMRI results. Results shown that Harm Avoidance trait people make use of right middle frontal gyrus and left superior frontal gyrus to discriminate between Coop and NoCoop. Cooperation as a trait makes use of the right superior temporal gyrus and the right precuneus to discriminate between Coop and NoCoop in positive social scenarios. Finally, Self-directedness trait people make use of the right inferior parietal lobe to discriminate between Coop and NoCoop in negative social scenarios and the right precuneus to discriminate between Coop and Strangers. An intuitive link between discrimination findings and behavioral patterns of those personality traits is proposed.

16.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 798-802, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018106

RESUMO

BACKGROUND: Parkinson's disease (PD) is a chronic condition that can be diagnosed and monitored by evaluating changes in the gait and arm movement parameters. In the gait movement, each cycle consists of two phases: stance and swing. Using gait analysis techniques, it is possible to get spatiotemporal variables derived from both phases. OBJECTIVE: In this paper, we compared two techniques: wavelet and peak detection. Previously, the wavelet technique was assessed for the gait phases detection, and peak detection was evaluated for arm swing analysis. These methods were evaluated using a low-cost RGB-D camera as data input source. This comparison could provide a unified and integrated method to analyze gait and arm swing signals. METHODS: Twenty-five PD patients and 25 age-matched, healthy subjects were included. Mann-Whitney U test was used to compare the continuous variables between groups. Hamming distances and Spearman rank correlation were used to evaluate the agreement between the signals and the spatiotemporal variables obtained by both methods. RESULTS: PD group showed significant reductions in speed (wavelet p = 0.001, peak detection p <0.001) and significantly greater swing (wavelet p = 0.003, peak detection p =0.005) and stance times (wavelet p = 0.003, peak detection p =0.004). Hamming distances showed small differences between the signals obtained by both methods (16 to 18 signal points). A very strong correlation (Spearman rho > 0.8, p <0.05) was found between the spatiotemporal variables obtained by each signal processing technique. CONCLUSION: Wavelet and peak detection techniques showed a high agreement in the signal obtained from gait data. The spatiotemporal variables obtained by both methods showed significant differences between the walking patterns of PD patients and healthy subjects. The peak detection technique can be used for integral motion analysis, providing the identification of the phases in the gait cycle, and arm swing parameters.Clinical Relevance- this establishes that peaks and wavelet techniques are comparable and may use it interchangeably to process signals from the gait of Parkinson's disease patients to support diagnosis and follow up made by a clinical expert.


Assuntos
Transtornos Neurológicos da Marcha , Doença de Parkinson , Marcha , Análise da Marcha , Humanos , Doença de Parkinson/diagnóstico , Caminhada
17.
Materials (Basel) ; 13(18)2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-32961838

RESUMO

This study shows the energy optimization and stabilization in the time of solutions composed of H2O + TX-100 + Multi-Wall Carbon Nanotubes (MWCNTs), used to improve the mechanical properties of Portland cement pastes. For developing this research, sonication energies at 90, 190, 290, 340, 390, 440, 490 and 590 J/g are applied to a colloidal substance (MWCNTs/TX-100 + H2O) with a molarity of 10 mM. Raman spectroscopy analyses showed that, for energies greater than 440 J/g, there are ruptures and fragmentation of the MWCNTs; meanwhile at energies below 390 J/g, better dispersions are obtained. The stability of the dispersion over time was evaluated over 13 weeks using UV-vis spectroscopy and Zeta Potential. With the most relevant data collected, sonication energies of 190, 390 and 490 J/g, at 10 mM were selected at the first and the fourth week of storage to obtain Portland cement specimens. Finally, we found an improvement of the mechanical properties of the samples built with Portland cement and solutions stored for one and four weeks; it can be concluded that the MWCNTs improved the hydration period.

18.
Neurol Int ; 12(1): 8401, 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32774822

RESUMO

Parkinson's disease (PD) has the second highest prevalence among neurodege - nerative diseases. In Colombia, PD population dynamics are currently unknown. Health records offer a unique resource to study frequency and multi-morbidity of chronic diseases. The aim of this research is to estimate prevalence and staging using administrative data (AD) provided by Health Maintenance Organizations (HMOs). A cross-sectional study was conducted using 2015 AD from two Colombian HMOs (4.312.928 beneficiaries, 9.01% of the affiliated Colombian population). PD prevalence and severity was estimated by age and sex. Prevalence was adjusted to WHO demographics. Age-adjusted PD prevalence was 205.89 per 100.000 inhabitants. Prevalence increment of 62.13% was found between those aged ≥40 years and those aged ≥50 years. Similarly, each extra decade (50-80+) represented an increment of 83.65%, 80.95%, and 35.10%. Between 40 and 89 years, males exhibited a significantly higher PD prevalence compared to females. Advanced PD was more frequent as age increased from 3.77% in the group between 40 to 49 years to 25.86% in those older than 89 years. More common related comorbidities were arterial hypertension, diabetes, and psychiatric disorders; the first two increased their frequency with age, and the last one maintained its prevalence across all age groups. AD sets are useful to estimate the prevalence and staging of PD. Prevalence of PD in Colombia is higher in men and increases with age, as well as disease severity.

19.
Sensors (Basel) ; 20(15)2020 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-32759667

RESUMO

In patients with Parkinson's disease (PD), arm swing changes are common, even in the early stages, and these changes are usually evaluated subjectively by an expert. In this article, hypothesize that arm swing changes can be detected using a low-cost, cloud-based, wearable, sensor system that incorporates triaxial accelerometers. The aim of this work is to develop a low-cost, assistive diagnostic tool for use in quantifying the arm swing kinematics of patients with PD. Ten patients with PD and 11 age-matched, healthy subjects are included in the study. Four feature extraction techniques were applied: (i) Asymmetry estimation based on root mean square (RMS) differences between arm movements; (ii) posterior-anterior phase and cycle regularity through autocorrelation; (iii) tremor energy, established using Fourier transform analysis; and (iv) signal complexity through the fractal dimension by wavelet analysis. The PD group showed significant (p < 0.05) reductions in arm swing RMS values, higher arm swing asymmetry, higher anterior-posterior phase regularities, greater "high energy frequency" signals, and higher complexity in their XZ plane signals. Therefore, the novel, portable system provides a reliable means to support clinical practice in PD assessment.


Assuntos
Acelerometria , Braço , Doença de Parkinson , Dispositivos Eletrônicos Vestíveis , Fenômenos Biomecânicos , Marcha , Humanos , Doença de Parkinson/diagnóstico , Caminhada , Punho
20.
Parkinsons Dis ; 2020: 2497386, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32733667

RESUMO

INTRODUCTION: Parkinson's disease (PD) is one of the most prevalent age-related neurodegenerative disorders. The progression of PD produces an important disease burden in patients due to functional impairment, which also has repercussions on caregivers. In addition, it has become a challenge for health systems, especially in developing countries, which have limited resources. Multidisciplinary teams with a community approach have proved effective in high-income countries; however, there is no reported literature in low- and middle-income countries about this kind of initiative. OBJECTIVE: This paper aims to document the experience of patients, caregivers, and experts in a community approach as an innovative model in a middle-income country. METHODS: A quantitative descriptive research was conducted. The selection criteria were having a PD diagnosis, attending with a caregiver to Saturdays in Motion (SIM), or being a clinical expert invited to SIM. PD patients and their caregivers answered three surveys on their points of view with respect to SIM: SIM and their quality of life (QoL) and PDQ-39 and Zarit, whereas clinical experts completed two questions related to the SIM program. Descriptive statistics were used to summarize the results of the surveys and clinical tests. RESULTS: Forty-eight, twenty-four, and twenty-one subjects answered surveys one, two, and three, respectively. In total, four clinical experts were interviewed. 87.9% of the patients consider that SIM activities improved their QoL. The most affected areas in PDQ-39 were those related to the social area. Around 66.6% of the caregivers reported a mild burden on Zarit and think that SIM enhances the PD patient's QoL. Clinical experts highlighted the sense of community and empathy. CONCLUSION: Our preliminary experience shows a multidisciplinary model with a community approach which redefines the traditional relationship between patients, caregivers, and clinical experts. This aim of this initiative is that education and empowerment patients and caregivers reach a better perception of QoL.

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