ABSTRACT
Lens biomechanical properties are critical for our eyes to accommodate. While it is well understood that lens mechanical properties change with age, different experimental techniques have been used over the years, with varying results on how the lens modulus changes. In this study, we developed a spatial-varying elasticity model to characterize the overall elastic modulus of the lens and establish its effect on accommodation. First, to validate the model, ex vivo porcine lenses underwent compression testing using biopsy punches of different diameters to change the percentage of nucleus within samples. Importantly, we found that, indeed, changing nucleus/cortex spatial ratio produces dramatic (â¼7-fold) increase in overall sample modulus. Comparing the model with human lens spatial ratios, we demonstrate how changing spatial mechanics are more influential than peak modulus changes on overall elastic modulus. Next, in vivo clinical measurements of the spatial-varying lens modulus were used to generate a simplified mechanical-optical model of accommodation. We defined an ellipsoid lens with patient-derived modulus and geometry measurements, and a statics simulation and ray tracing analysis were performed through the deformed and undeformed lens. The resulting accommodation estimates agree with general accommodation expectations.
ABSTRACT
Bio-inspired optical systems have recently been developed using polarizers and liquid or rigid lenses. In this work, we propose a bio-inspired opto-mechatronic system that imitates the accommodation and regulation of light intensity as the human eye does. The system uses a polymeric lens as a cornea, an adjustable diaphragm as an iris, a tunable solid elastic lens as a crystalline lens, and a commercial sensor as a retina. We also present the development of the electronic control system to accommodate and regulate the amount of light that enters the system, for which two stepper motors, an Arduino control system, and light and movement sensors are used. The characterization of the system is presented together with the results obtained, where it can be seen that the system works in an acceptable range as the human eye does.
Subject(s)
Lens, Crystalline , Lenses , Optical Devices , Humans , Lighting , CorneaABSTRACT
Even though the physical nature of shear and longitudinal moduli are different, empirical correlations between them have been reported in several biological systems. This correlation is of fundamental interest and immense practical value in biomedicine due to the importance of the shear modulus and the possibility to map the longitudinal modulus at high-resolution with all-optical spectroscopy. We investigate the origin of such a correlation in hydrogels. We hypothesize that both moduli are influenced in the same direction by underlying physicochemical properties, which leads to the observed material-dependent correlation. Matching theoretical models with experimental data, we quantify the scenarios in which the correlation holds. For polymerized hydrogels, a correlation was found across different hydrogels through a common dependence on the effective polymer volume fraction. For hydrogels swollen to equilibrium, the correlation is valid only within a given hydrogel system, as the moduli are found to have different scalings on the swelling ratio. The observed correlation allows one to extract one modulus from another in relevant scenarios.
Subject(s)
Hydrogels , Polymers , Hydrogels/chemistry , Polymers/chemistry , Spectrum Analysis , Models, Theoretical , ViscosityABSTRACT
Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici (Fol), causes losses in tomato production worldwide, with major impacts on Californian tomato processing. Single-gene resistance is the primary management tool, but its efficacy has been compromised following the emergence of two successive resistance-breaking races, which, in California, emerged within 12 years of resistance deployment. Fol race 3-resistant (F3) processing tomato cultivars (containing the I3 resistance gene) were deployed in the state starting in approximately 2009. The emergence of a new resistance-breaking race (which would be called race 4) is imminent, and early detection will be critical to delay the spread while new resistance is sought. The detection of Fol race 4 is challenged by the lack of validated, rapid, and accurate diagnostic tools. In evaluating in planta phenotyping methods, this study found that rapid seedling phenotyping is not reliable and generates false positives for nonpathogens. Longer (10 weeks) mature plant assays are the most reliable, but may not be sufficiently timely. As an additional challenge, based on field and greenhouse studies, Fol race 3 can cause symptoms in resistant F3 cultivars at frequencies greater (30%) than expected for off-types (<2%). We developed a three-F3 cultivar in planta assay to overcome the challenges this posed to differentiating Fol race 3 and Fol race 4. Using the assay, we determined that all putative resistance-breaking cases were Fol race 3; Fol race 4 was not detected in these early survey efforts. These results highlight the need for developing rapid Fol race 4 detection tools and a better understanding of the factors underlying inconsistent I3 gene expression in Fol race 3.
ABSTRACT
ABSTRACT: Black shading nets are widely used in the protected cultivation of vegetables as a technique for controlling light and temperature, while the colored shading nets, with special optical properties to improve the use of solar radiation, appeared recently in the agricultural plastics market. Light quality transmitted by gray, aluminized, pearl, blue, red and black (control) nets with 30% shade was evaluated, as well as its effects on photosynthetic properties and fruits production of cucumber plants. Treatments (shade nets) were established under a randomized complete block design with four repetitions. The red net transmitted 23.7 and 40.3% more photosynthetic photon flux density (400 to 700nm) and red light (600 to 700nm) and the blue net transmitted 36% more blue light (400 to 500nm) in comparison with the respective transmissions of black net. All nets increased the photosynthetic responses: transpiration, stomatal conductance and CO2 assimilation, observed in plants grown under black net. Leaf greenness (41.6 SPAD units) and foliar area (90dm2) increased 22.8 and 38.9% with the red net, while the dry weight of leaf (52.5g) increased 21.9% with pearl net. Pearl, red, aluminized and blue nets showed to be viable alternatives because the production of fruit increased in 71, 48, 46 and 46%, respectively, in comparison with the conventional black net (52t ha-1).
RESUMO: As malhas de sombreamento preto são amplamente utilizadas no cultivo protegido de hortaliças como uma técnica para controlar a luz e a temperatura; enquanto as malhas de sombreamento coloridas, com propriedades ópticas especiais para melhorar o uso da radiação solar, apareceram recentemente no mercado de plásticos agrícolas. A qualidade de luz transmitida por malhas cinza, aluminizada, pérola, azul, vermelha e preta (controle) com 30% de sombreamento foi avaliada, assim como seus efeitos nas propriedades fotossintéticas e na produção de frutos de plantas de pepino. Os tratamentos (malhas de sombreamento) foram estabelecidos sob o desenho de blocos completos casualizados, com quatro repetições. A malha vermelha transmitiu 23,7 e 40,3% mais densidade de fluxo de fótons fotossintéticos (400 a 700nm) e luz vermelha (600 a 700nm) e a malha azul transmitiu 36% mais luz azul (400 a 500nm) em comparação com as respectivas transmissões de malha preta. Todas as malhas aumentaram as respostas fotossintéticas: transpiração, condutância estomática e assimilação de CO2, observadas em plantas cultivadas sob malha preta. O verde da folha (41,6 unidades SPAD) e a área foliar (90dm2) aumentaram 22,8 e 38,9% com a malha vermelha, enquanto o peso seco da folha (52,5g) aumentou 21,9% com a malha pérola. As malhas pérola, vermelha, aluminizada e azul mostraram-se como alternativas viáveis, pois a produção de frutos aumentou em 71, 48, 46 e 46%, respectivamente, em comparação à malha convencional preta (52t ha-1).
ABSTRACT
Disinfection of an advanced primary effluent using a continuous-flow combined peracetic acid/ultraviolet (PAA/UV) radiation system was evaluated. The purpose was to determine whether the maximum microbial content, established under Mexican standards for treated wastewaters meant for reuse--less than 240 most probable number fecal coliforms (FC)/100 mL--could be feasibly accomplished using either disinfectant individually, or the combined PAA/UV system. This meant achieving reduction of up to 5 logs, considering initial concentrations of 6.4 x 10(+6) to 5.8 x 10(+7) colony forming units/100 mL. During the tests performed under these experiments, total coliforms (TC) were counted because FC, at the most, will be equal to TC. Peracetic acid disinfection achieved less than 1.5 logs TC reduction when the C(t) x t product was less than 2.26 mg x minimum (min)/L; 3.8 logs for C(t) x t 4.40 mg x min/L; and 5.9 logs for C(t) x t 24.2 mg x min/L. In continuous-flow UV irradiation tests, at a low-operating flow (21 L/min; conditions which produced an average UV fluence of 13.0 mJ/cm2), the highest TC reduction was close to 2.5 logs. The only condition that produced a disinfection efficiency of approximately 5 logs, when both disinfection agents were used together, was the combined process dosing 30 mg PAA/L at a pilot plant flow of 21 L/min and contact time of 10 minutes to attain an average C(t) x t product of 24.2 mg x min/L and an average UV fluence of 13 mJ/cm2. There was no conclusive evidence of a synergistic effect when both disinfectants were employed in combination as compared to the individual effects achieved when used separately, but this does not take into account the nonlinearity (tailing-off) of the dose-response curve.
Subject(s)
Disinfectants/pharmacology , Disinfection/methods , Peracetic Acid/pharmacology , Ultraviolet Rays , Water Purification/methodsABSTRACT
This study was conducted to evaluate the ozone, UV and O3/UV processes for the reuse of sewage treatment plant effluent (Universidad Autonoma Metropolitana Azcapotzalco wastewater treatment plant). The ozone/UV process was compared to individual ozone and the UV processes and control parameters were total and fecal coliforms. Different ozone concentrations (6-12 mg O3/min) and different UV fluencies (6.7-20.12 mJ/cm²) were tested. It is possible to conclude than none of the processes achieved the disinfection levels required to comply with the Mexican standard NOM-003-SEMARNAT-1997. The continuous ozone process offered the lower total and fecal coliforms reductions, while UV light resulted a disinfection agent with higher germicide power than ozone. The maximum logarithmic reduction achieved due to the combined ozone/UV process was of 2.04 for fecal coliforms and of 2.17 for total coliforms. The next 8 combinations showed lower removal efficiencies, but always higher than those obtained with the single ozone or UV processes. The ozone/UV process was highly effective for the disinfection and a synergistic effect was observed.
Subject(s)
Ozone , Ultraviolet Rays , Waste Disposal, Fluid/methods , Water Purification/methodsABSTRACT
The use of iron in a +6 valence state, (Fe (VI), as FeO4(-2)) was tested as a novel alternative for wastewater disinfection and decontamination. The removal of organic matter (OM) and index microorganisms present in an effluent of a wastewater plant was determined using FeO4(-2) without any pH adjustment. It was observed that concentrations of FeO4(-2) ranging between 5 and 14 mg l(-1) inactivated up to 4-log of the index microorganisms (initial concentration c.a. 10(6) CFU/100 ml) and achieved OM removal up to almost 50%. The performance of FeO4(-2) was compared with OM oxidation and disinfection using hypochlorite. It was observed that hypochlorite was less effective in OM oxidation and coliform inactivation than ferrate. Results of this work suggest that FeO4(-2) could be an interesting oxidant able to deactivate pathogenic microorganisms in water with high OM content and readily oxidize organic matter without jeopardizing its efficiency on microorganism inactivation.
Subject(s)
Iron/chemistry , Waste Disposal, Fluid/methods , Water Purification/methods , Enterobacteriaceae , Humans , Hydrogen-Ion Concentration , Nephelometry and Turbidimetry , Oxidation-ReductionABSTRACT
Se estudia la mortalidad, incidencia, prevalencia y algunas características clínicas y epidemiológicas de la fiebre reumática (FR), y la enfermedad reumática (ERC) en 3 provincias del pais (Ciudad de La Habana, Santiago de Cuba y Pinar del Rio). Se utilizó em método epidemiológico, basado en el estudio de estadísticas vitales, aplicación de registros permanente de la enfermedad y encuesta a la población escolar en las provincias escogidas. Se utilizaron los criterios de Jones revisados y modificados. La mortalidad por ERC y FR en todas las edades en Cuba disminuyó desde 6,00 por cada 100 000 en 1963 a 1965, hasta tasas alrededor de 2,0 en los años 80. La mortalidad por FR aguda está por debajo de 0,2. La incidencia de FR aguda primer ataque es de 12,0 por 100 000 más alta en las provincias de Pinar del Río y Santiago de Cuba. Es mayor en las edades de 5 a 9 años y similar en uno y otro sexo. La enfermedad se presenta con más severidad en las recurrencias y en las provincias de Santiago de Cuba y Pinar del Río. La prevalencia total fue de 5.8 por 1 000 y fue más alta en las provincias de Santiago de Cuba y Pinar del Río (6.5 y 8,5). Correspondieron a estas provincias las frecuencias más elevadas de cardiopatía reumática, así como un mayor número de pacientes que ignoraban que padecían la enfermedad
Subject(s)
Child, Preschool , Child , Adolescent , Humans , Rheumatic Fever/mortality , Rheumatic Fever/epidemiology , Vital StatisticsABSTRACT
Se presenta la evaluación de la segunda versión del sistema Cardiocid, programa de diagnóstico electrocardiográfico automatizado. En cuatro instituciones diferentes se registró el electrocardiograma en 1134 pacientes adultos a velocidad y calibración estándard y se compararon los diagnósticos formulados por el sistema con los planteados por los cardiólogos que desconocían los del primero. Se encontró coincidencia en todos los diagnósticos en el 92,4% del total de trazados; en los normales fue del 95,4 % y en los anormales de 91,5 %. En el total de los diagnósticos planteados por los médicos la concordancia fue del 97,3 %. La especificidad y el valor predictivo negativo del Cardiocid fueron superiores al 99% en 79 de las 80 posibilidades del diagnóstico del programa. Sólo en 6 de ellas la sensibilidad y el valor predictivo positivo fueron inferiores al 80%; en el resto superaron esta cifra y se destaca que en el 79% y en el 66 % respectivamente del total de diagnóstico que fueron identificados por los cardiólogos la sensibilidad y el valor predictivo positivo fueron del 100% cada uno. Los criterios con sensibilidad y/o valor predictivo positivo < 80 % fueron: presencia de marcapasos artificial, algunos trastornos del ritmo y algunos relacionados con la onda P. Los datos sugieren que el Cardiocid tiene una alta eficiencia para el análisis automatizado de electrocardiograma en adultos y se recomienda su introducción en la práctica clínica
Subject(s)
Adult , Humans , Electronic Data Processing , Electrocardiography , CubaABSTRACT
Se estudió la incidencia y las características clinicoepidemiológicas de la fiebre reumática aguda (FR) en los años 1972 y 1982 entre los residentes habituales de la provincia Ciudad de La Habana, con edades entre 5 y 14 años. Se registraron todos los casos de pacientes con probable FR (códigos 390-398 y 710-715) ingresados en los hospitales pediátricos o con Servicio de Pediatría en el período de estudio. Se les aplicaron los criterios de Jones modificados y se incluyeron o no en el estudio. Se observó una marcada disminución de la incidencia de 38,1 por 100 000 habitantes en 1972 a 10,5 en 1982, más marcada en las recurrencias (4,7 veces menos) que en los primeros ataques (3,4 veces). También se observó una disminución en la severidad de la enfermedad; en 1972 presentó carditis pura o asociada el 40
, insuficiencia cardíaca el 10
, secuelas vasculares el 31,9
y falleció el 1,5
, ambos en recurrencia de la FR, mientras que en 1982 el 34,4
tuvo carditis pura o asociada, el 6
insuficiencia cardíaca, el 20
secuelas valvulares y no hubo fallecidos (AU)
Subject(s)
Child, Preschool , Child , Adolescent , Humans , Male , Female , Rheumatic Fever/epidemiologyABSTRACT
Se estudió la incidencia y las características clinicoepidemiológicas de la fiebre reumática aguda (FR) en los años 1972 y 1982 entre los residentes habituales de la provincia Ciudad de La Habana, con edades entre 5 y 14 años. Se registraron todos los casos de pacientes con probable FR (códigos 390-398 y 710-715) ingresados en los hospitales pediátricos o con Servicio de Pediatría en el período de estudio. Se les aplicaron los criterios de Jones modificados y se incluyeron o no en el estudio. Se observó una marcada disminución de la incidencia de 38,1 por 100 000 habitantes en 1972 a 10,5 en 1982, más marcada en las recurrencias (4,7 veces menos) que en los primeros ataques (3,4 veces). También se observó una disminución en la severidad de la enfermedad; en 1972 presentó carditis pura o asociada el 40 %, insuficiencia cardíaca el 10 %, secuelas vasculares el 31,9 % y falleció el 1,5 %, ambos en recurrencia de la FR, mientras que en 1982 el 34,4 % tuvo carditis pura o asociada, el 6 % insuficiencia cardíaca, el 20 % secuelas valvulares y no hubo fallecidos
Subject(s)
Child, Preschool , Child , Adolescent , Humans , Male , Female , Rheumatic Fever/epidemiologyABSTRACT
Se hace un análisis histórico general del desarrollo y la evolución de la asistencia social, la cual pasa de la caridad y limosna cristiana a la beneficiencia pública, hasta arribar a una concepción política, social y económica de la asistencia. Se señala la forma y los medios bajo y con que se proporcionaba asistencia social, así como las condiciones económicas, sociales e ideológicas que propician la transformación de la concepción de la asistencia social, haciéndose hincapié en el movimiento de Independencia; la promulgación de las Leyes de Reforma y la Revolución Mexicana. Todo lo cual culmina en 1937 con la creación de la Secretaría de la Asistencia Pública, con lo cual se legitima la obligatoriedad del Estado de intervenir en favor de los débiles sociales, emanada de la ley de la beneficiencia. La concepción de la asistencia dejó atrás los conceptos de caridad y beneficiencia, ahora se ha erigido en un derecho a ser asistido, por un lado, y, por otro, en obligación del Estado de proporcionar ayuda y preparación y posibilidades para el trabajo productivo
Subject(s)
Social Support/history , MexicoABSTRACT
Se hace un análisis histórico general del desarrollo y la evolución de la asistencia social, la cual pasa de la caridad y limosna cristiana a la beneficiencia pública, hasta arribar a una concepción política, social y económica de la asistencia. Se señala la forma y los medios bajo y con que se proporcionaba asistencia social, así como las condiciones económicas, sociales e ideológicas que propician la transformación de la concepción de la asistencia social, haciéndose hincapié en el movimiento de Independencia; la promulgación de las Leyes de Reforma y la Revolución Mexicana. Todo lo cual culmina en 1937 con la creación de la Secretaría de la Asistencia Pública, con lo cual se legitima la obligatoriedad del Estado de intervenir en favor de los débiles sociales, emanada de la ley de la beneficiencia. La concepción de la asistencia dejó atrás los conceptos de caridad y beneficiencia, ahora se ha erigido en un derecho a ser asistido, por un lado, y, por otro, en obligación del Estado de proporcionar ayuda y preparación y posibilidades para el trabajo productivo
