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1.
PLoS Biol ; 17(12): e3000553, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31856161

RESUMO

Holo-tomographic microscopy (HTM) is a label-free microscopy method reporting the fine changes of a cell's refractive indices (RIs) in three dimensions at high spatial and temporal resolution. By combining HTM with epifluorescence, we demonstrate that mammalian cellular organelles such as lipid droplets (LDs) and mitochondria show specific RI 3D patterns. To go further, we developed a computer-vision strategy using FIJI, CellProfiler3 (CP3), and custom code that allows us to use the fine images obtained by HTM in quantitative approaches. We could observe the shape and dry mass dynamics of LDs, endocytic structures, and entire cells' division that have so far, to the best of our knowledge, been out of reach. We finally took advantage of the capacity of HTM to capture the motion of many organelles at the same time to report a multiorganelle spinning phenomenon and study its dynamic properties using pattern matching and homography analysis. This work demonstrates that HTM gives access to an uncharted field of biological dynamics and describes a unique set of simple computer-vision strategies that can be broadly used to quantify HTM images.


Assuntos
Microscopia de Fluorescência/métodos , Organelas/fisiologia , Refratometria/métodos , Células HeLa , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imagem Tridimensional/métodos , Metabolismo dos Lipídeos , Mitocôndrias/metabolismo
2.
Ann Biol Clin (Paris) ; 77(4): 381-389, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31418699

RESUMO

The SFBC working group aimed to deal with biological tests outside the french nomenclature that may be useful in the context of urinary exploration of metabolism. This section will be divides into three parts: 1) nutritional assessment using urinary urea; 2) metabolic assessment of urolithiasis; 3) exploration of tubulopathies. National and international recommendations support the evaluation of nutritional status from urea measurements in urine and dialysate with the following indications: primary metabolic evaluation of urolithiasis patients, monitoring of protein intake in chronic renal failure stage 3 or stage 5D with residual diuresis. For the management of the urolithiasis disease, biomedical tests recommended by the national and international guidelines are the measurement of the urinary density using refractometry in the primary metabolic evaluation as well as the determination of oxalemia in the diagnosis (patients with GFR< 30 mL/min/1.73 m2) and follow-up (patients with GFR< 60 mL/min/1.73 m2) of primary hyperoxaluria. The determination of the bicarbonaturia is retained for the in depth exploration of urolithiasis and tubular acidosis. The measure of chlore in urine is used to evaluate the volume status during metabolic alkalosis and to calculate the urinary anionic gap during metabolic acidosis.


Assuntos
Metabolismo Energético/fisiologia , Nefropatias/diagnóstico , Avaliação Nutricional , Urinálise/métodos , Urolitíase/diagnóstico , Humanos , Nefropatias/patologia , Nefropatias/urina , Túbulos Renais/patologia , Padrões de Referência , Refratometria/métodos , Refratometria/normas , Urinálise/normas , Urolitíase/urina
3.
Food Chem ; 298: 125090, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31272055

RESUMO

In this study, molecular properties of wheat starch from three different types of breads were analyzed using asymmetric flow field-flow (AF4) connected to multi-angle light scattering (MALS) and differential refractive index (dRI) detectors. This analysis allowed the determination of molecular properties, i.e. molar mass (M), root-mean-square radius (rrms), apparent density (ρapp) and conformation. Complementary analyses, such as resistant starch and amylose content, were also performed. The results show that wheat starch extracted from breads can have different properties reflected in changes in M, rrms and ρapp. In addition, the results suggest that some of the changes in molecular properties may be related to the presence of resistant starch.


Assuntos
Pão/análise , Fracionamento por Campo e Fluxo/métodos , Refratometria/métodos , Amido/química , Triticum/química , Amilose/análise , Bolívia , Análise de Alimentos/métodos , Peso Molecular , Espalhamento de Radiação
4.
Sensors (Basel) ; 19(12)2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31212999

RESUMO

Breath gas analysis is a promising tool for medical research and diagnosis. A particularly powerful technological approach is millimeter-wave/terahertz (mmW/THz) spectroscopy, because it is a very sensitive and highly selective technique. In addition, it offers the potential for compact and affordable sensing systems for wide use. In this work, we demonstrate the capability of a mmW/THz spectrometer for breath analysis. Samples from three volunteers and a sample from ambient air were analyzed with respect to 31 different molecular species. High-resolution absorption spectra were measured by scanning two absorption lines from each species. Out of the 31, a total of 21 species were detected. The results demonstrate the potential of mmW/THz spectroscopy for breath analysis.


Assuntos
Testes Respiratórios/métodos , Gases/análise , Espectroscopia Terahertz/métodos , Fenômenos Eletromagnéticos , Humanos , Refratometria/métodos
5.
J. optom. (Internet) ; 12(2): 99-110, abr.-jun. 2019. tab, graf
Artigo em Inglês | IBECS | ID: ibc-180890

RESUMO

Purpose: To determine the agreement and validity of keratometric measurements in children with the Nidek ARK-510A auto-refractokeratometer compared to rotating Scheimpflug imaging with Pentacam and biograph with Lenstar LS 900. Methods: This study was conducted on 5620 schoolchildren aged 6-12 years in Shahroud, Iran. Minimum and maximum keratometry values and corneal astigmatism magnitude were compared by calculation of Paired difference, interclass correlation coefficient, and 95% limits of agreement (LoA) between devices. Results: After applying the exclusion criteria, 4215 right eyes were enrolled into the study. Mean minimum keratometry with Nidek ARK-510A, Pentacam, and Lenstar was 43.13 ± 1.51, 43.14 ± 1.48, and 42.87 ± 1.46 diopters (D), respectively, and mean maximum keratometry was 43.97 ± 1.59, 44.00 ± 1.56, and 43.75 ± 1.54D, respectively. Nidek ARK-510A overestimated minimum and maximum keratometry by 0.25 ± 0.37 and 0.22 ± 0.41, respectively, compared to Penatcam. The LoA between Nidek ARK-510A and Pentacam for minimum and maximum keratometry measurements were -0.98 to 0.47D and −1.02 to 0.57D, respectively. The LoA between Nidek ARK-510A and Lenstar for minimum and maximum keratometry measurements were -0.70 to 0.72D and -0.79 to 0.85D, respectively. The agreement between devices was best in emmetropes, worst in hyperopes. For astigmatic vector components, the agreements between devices were poor but best agreement was between Nidek ARK-510A and Pentacam. Conclusions: Keratometry measurement with Nidek ARK-510A was not significantly different from Pentacam and Lenstar, and this device can be used in screening programs in emmetropes


Objetivo: Determinar la concordancia y validez de las mediciones queratométricas en niños con el autorefractoqueratómetro Nidek ARK-510A, comparadas con las imágenes de Scheimpflug con Pentacam y el biómetro Lenstar LS 900. Métodos: Este estudio se realizó en 5.620 niños, de edades comprendidas entre 6 y 12 años, en Shahroud, Irán. Se compararon los valores queratométricos mínimo y máximo y la magnitud del astigmatismo corneal mediante cálculo de diferencia pareada, coeficiente de correlación inter-clase, y límites de comcordancia del 95% (LoA) entre dispositivos. Resultados: Tras aplicar los criterios de exclusión, se incluyeron 4.215 ojos derechos en el estudio. Los valores de queratometría mínima media con Nidek ARK-510A, Pentacam y Lenstar fueron de 43,13 ± 1,51, 43,14 ± 1,48, y 42,87 ± 1,46 dioptrías (D), respectivamente, siendo los valores de queratometría máxima media de 43,97 ± 1,59, 44 ± 1,56, y 43,75 ± 1,54 D, respectivamente. Nidek ARK-510A sobre-estimó la queratometría mínima y máxima en 0,25 ± 0,37 y 0,22 ± 0,41, respectivamente, en comparación con Penatcam. El LoA entre Nidek ARK-510A y Pentacam para las mediciones de queratometría mínima y máxima fue de -0,98 a 0,47 D y -1,02 a 0,57 D, respectivamente. El LoA entre Nidek ARK-510A y Lenstar para las mediciones de queratometría mínima y máxima fue de -0,7 a 0,72 D y -0,79 a 0,85 D, respectivamente. El acuerdo entre dispositivos fue mejor en emétropes, y peor en hipermétropes. Para los componentes del vector astigmático, los acuerdos entre dispositivos fueron débiles, aunque existió una mejor concordancia entre Nidek ARK-510A y Pentacam. Conclusiones: La medición de la queratometría realizada con Nidek ARK-510A no fue significativamente diferente a la realizada con Pentacam y Lenstar, pudiendo utilizarse este dispositivo en los programas de chequeo en emétropes


Assuntos
Humanos , Masculino , Feminino , Criança , Refratometria/métodos , Erros de Refração/diagnóstico , Astigmatismo/diagnóstico , Emetropia/fisiologia , Refratometria/instrumentação , Valores de Referência , Biometria/métodos , Estudos Transversais
6.
Sensors (Basel) ; 19(9)2019 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-31083614

RESUMO

An optical cavity-based sensor using a differential detection method has been proposed for point-of-care diagnostics. We developed a low-cost and portable optical cavity-based sensor system using a 3D printer and off-the-shelf optical components. In this paper, we demonstrate the sensing capability of the portable system through refractive index measurements. Fabricated optical cavity samples were tested using the portable system and compared to simulation results. A referencing technique and digital low pass filtering were applied to reduce the noise of the portable system. The measurement results match the simulation results well and show the improved linearity and sensitivity by employing the differential detection method. The limit of detection achieved was 1.73 × 10-5 Refractive Index Unit (RIU), which is comparable to other methods for refractive index sensing.


Assuntos
Técnicas Biossensoriais/economia , Técnicas Biossensoriais/métodos , Desenho de Equipamento/métodos , Fibras Ópticas , Refratometria/métodos
7.
J Immunol Res ; 2019: 5474519, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31143781

RESUMO

Detection and analysis of antigen-antibody reaction is one of the most critical detection techniques in the fields of medicine, biology, environmental science, and food safety. Traditional and classical methods for detecting antigen and antibody encounter many problems, such as time-consuming, high cost, and low accuracy. A novel immune microsphere imaging technique by the microlens is used to test the changes of refractive index before and after antigen-antibody reaction. It can quickly perform qualitative and quantitative determination for antigen-antibody reaction without any labeling, premodification, postwashing, and expensive enzymes. Here, we feature and discuss its principle and advantages, structure of a microlens immunoassay instrument, and potential in measuring clinical samples. It is promising to be developed for application to diagnosis of clinical diseases.


Assuntos
Reações Antígeno-Anticorpo , Imunoensaio/instrumentação , Refratometria/métodos , Anticorpos/metabolismo , Antígenos/metabolismo , Diagnóstico por Imagem/tendências , Humanos , Microesferas
8.
Opt Lett ; 44(10): 2386-2389, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31090688

RESUMO

Controlling light propagation through a step-index multimode optical fiber (MMF) has several important applications, including biological imaging. However, little consideration has been given to the coupling of fiber and tissue optics. In this Letter, we characterized the effects of tissue-induced light distortions, in particular those arising from a mismatch in the refractive index of the pre-imaging calibration and biological media. By performing the calibration in a medium matching the refractive index of the brain, optimal focusing ability was achieved, as well as a gain in focus uniformity within the field-of-view. These changes in illumination resulted in a 30% improvement in spatial resolution and intensity in fluorescence images of beads and live brain tissue. Beyond refractive index matching, our results demonstrate that sample-induced aberrations can severely deteriorate images from MMF-based systems.


Assuntos
Hipocampo/anatomia & histologia , Luz , Neurônios/citologia , Fibras Ópticas , Refratometria/métodos , Animais , Calibragem , Modelos Biológicos , Óptica e Fotônica , Ratos , Ratos Wistar
9.
Opt Lett ; 44(6): 1359-1362, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30874650

RESUMO

The health of a eukaryotic cell depends on the proper functioning of its cell organelles. Characterizing these nanometer- to micrometer-scaled specialized subunits without disturbing the cell is challenging but can also provide valuable insights regarding the state of a cell. We show that objective-based scanning surface plasmon resonance microscopy can be used to analyze the refractive index of cell organelles quantitatively in a noninvasive and label-free manner with a lateral resolution at the diffraction limit.


Assuntos
Microscopia/métodos , Organelas/metabolismo , Refratometria/métodos , Ressonância de Plasmônio de Superfície , Animais , Neurônios/citologia , Ratos
10.
Arch. Soc. Esp. Oftalmol ; 94(3): 130-133, mar. 2019. ilus
Artigo em Espanhol | IBECS | ID: ibc-178314

RESUMO

Presentamos el caso clínico de una mujer epiléptica de 29 años en tratamiento con topiramato 25 mg/día desde 9 días previos a la presentación del cuadro, que acude a urgencias por disminución de la agudeza visual (AV) tras incrementar la dosis a 50mg/día 2 días antes. En la exploración presenta un glaucoma agudo de ángulo cerrado (GAAC) bilateral y estrías maculares en ambos ojos (AO) objetivadas mediante retinografía y tomografía de coherencia óptica (OCT). El GAAC es un efecto secundario conocido y ampliamente descrito del topiramato, sin embargo, las estrías maculares que ocasionalmente acompañan al GAAC, aunque se han descrito anteriormente en otros casos, muy pocos las documentan mediante imágenes de retinografía y OCT. Es importante diferenciar un caso de GAAC inducido por topiramato de un caso de GAAC primario ya que difieren en su presentación clínica, mecanismo de acción y tratamiento. Su manejo inadecuado puede tener consecuencias potencialmente graves


We report the case of a 29-year-old epileptic woman who had been on treatment with topiramate 25 mg/day for 9 days. She was referred to the Emergency Department due to reduction in far visual acuity (VA) after increasing the dose to 50mg/day two days before. The ocular examination showed bilateral acute angle closure glaucoma (AACG) and macular striae in both eyes (AO) observed by Retinography and Optical Coherence Tomography (OCT). The AACG is a well-known side effect of topiramate, but the macular striae rarely accompanies it. Although macular striae have been previously described in other cases, very few document those using retinography and OCT images. Therefore, it is important to differentiate a case of AACG induced by topiramate from a case of primary AACG, since they differ in their clinical presentation, mechanism of action, and treatment. Mismanagement can have potentially serious consequences


Assuntos
Humanos , Feminino , Adulto , Glaucoma de Ângulo Fechado/induzido quimicamente , Glaucoma de Ângulo Fechado/diagnóstico por imagem , Anticonvulsivantes/efeitos adversos , Acuidade Visual , Tomografia de Coerência Óptica , Refratometria/métodos , Manitol/uso terapêutico
11.
J. optom. (Internet) ; 12(1): 22-29, ene.-mar. 2019. grab, tab
Artigo em Inglês | IBECS | ID: ibc-178509

RESUMO

Background: Accommodation is often recorded at a low sampling rate using devices such as autorefractors that are designed to measure the static refractive error. It is therefore important to determine if that resolution is sufficient to accurately measure the dynamic properties of accommodation. The current study provides both theoretical and empirical evidence on the ideal sampling rate necessary to measure a dynamic response. Methods: Accommodative and disaccommodative step stimuli ranging from 1-3 D (1 D steps) were presented using a Badal optical system. Responses from 12 children (8-13 years) and 6 adults (20-35 years) were recorded using a dynamic photorefractor (DPR). Fast Fourier transformation was applied to the unsmoothed dynamic responses including position, velocity and acceleration. Also, velocity and acceleration main sequence (MS) characteristics were compared between three photorefractor conditions on 3 subjects. Results: The Nyquist sampling limit necessary to accurately estimate position, velocity and acceleration was at least 5, 10 and 70 Hz, respectively. Peak velocity and acceleration were significantly underestimated at a lower rate (p < 0.5). However, the slope of MS remained invariant with sampling rate (p > 0.5). Conclusion: Contrary to the previous findings, a dynamic accommodative response exhibited frequencies larger than 10Hz. Stimulus direction and amplitude had no influence on the frequencies present in the dynamic response. Peak velocity and acceleration can be significantly underestimated when sampled at a lower rate. Taken as a whole, low sampling rate instruments can accurately estimate static accommodation, however, caution needs to be exercised when using them for dynamic accommodation


La acomodación se registra a menudo a una tasa de muestreo baja, utilizando dispositivos tales como los autorrefractómetros que están diseñados para medir el error refractivo estático. Por tanto, es importante determinar si dicha resolución es suficiente para medir con precisión las propiedades dinámicas de la acomodación. El estudio actual aporta evidencia tanto teórica como empírica acerca de la tasa de muestreo necesaria para medir una respuesta dinámica. Métodos: Se presentaron estímulos de alteraciones de estimulación y relajación (desacomodación) de la acomodación que oscilaron entre 1 y 3 D (pasos de 1 D) utilizando un sistema óptico Badal. Se registraron las respuestas de 12 niños (de 8 a 13 años) y 6 adultos (de 20 a 35 años) utilizando un sistema de fotorrefracción dinámico (DPR). La transformación rápida de Fourier se aplicó a las respuestas dinámicas no uniformes incluyendo posición, velocidad y aceleración. También se compararon las características de la secuencia principal de velocidad y aceleración entre las tres situaciones del sistema de fotorrefracción en 3 sujetos. Resultados: El límite de muestreo de Nyquist necesario para calcular con precisión la posición, velocidad y aceleración fue de al menos 5, 10 y 70Hz respectivamente. La velocidad y aceleración máximas se subestimaron significativamente a una tasa inferior (p < 0,5). Sin embargo, la pendiente de la secuencia principal permaneció invariable con la tasa de muestreo (p > 0,5). Conclusión: Contrariamente a los hallazgos anteriores, la respuesta acomodativa dinámica mostró unas frecuencias superiores a 10Hz. La dirección y amplitud del estímulo no influyeron en las frecuencias presentes en la respuesta dinámica. La velocidad y aceleración máximas pueden subestimarse significativamente cuando se muestrean a una tasa menor. En conjunto, los instrumentos de baja tasa de muestreo pueden calcular con precisión la acomodación estática; sin embargo, debe actuarse con precaución a la hora de calcular la acomodación dinámica


Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Adulto Jovem , Adulto , Acomodação Ocular/fisiologia , Optometria/métodos , Refratometria/métodos , Análise de Fourier , Optometria/instrumentação , Refração Ocular/fisiologia , Refratometria/instrumentação
12.
Sensors (Basel) ; 19(3)2019 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-30696020

RESUMO

Back scatter interferometry (BSI) is a sensitive method for detecting changes in the bulk refractive index of a solution in a microfluidic system. Here we demonstrate that BSI can be used to directly detect enzymatic reactions and, for the first time, derive kinetic parameters. While many methods in biomedical assays rely on detectable biproducts to produce a signal, direct detection is possible if the substrate or the product exert distinct differences in their specific refractive index so that the total refractive index changes during the enzymatic reaction. In this study, both the conversion of glucose to glucose-6-phosphate, catalyzed by hexokinase, and the conversion of adenosine-triphosphate to adenosine di-phosphate and mono-phosphate, catalyzed by apyrase, were monitored by BSI. When adding hexokinase to glucose solutions containing adenosine-triphosphate, the conversion can be directly followed by BSI, which shows the increasing refractive index and a final plateau corresponding to the particular concentration. From the initial reaction velocities, KM was found to be 0.33 mM using Michaelis⁻Menten kinetics. The experiments with apyrase indicate that the refractive index also depends on the presence of various ions that must be taken into account when using this technique. This study clearly demonstrates that measuring changes in the refractive index can be used for the direct determination of substrate concentrations and enzyme kinetics.


Assuntos
Trifosfato de Adenosina/química , Catálise , Hexoquinase/química , Interferometria/métodos , Glucose/química , Glucose-6-Fosfato/química , Cinética , Microfluídica/métodos , Refratometria/métodos , Soluções/química
13.
Chemosphere ; 214: 424-429, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30273875

RESUMO

Plastic pollution in natural water bodies is an emerging problem that requires quick actions. Recently, the role of micro- and nanoplastics in pollution and health issues has been realized and taken seriously. In this paper, we have studied optical properties, such as NIR spectra and refractive index, of some common plastic materials and present a method and data to screen especially problematic transparent plastics with rough surface in aquatic environments. We also give an outlook of possible optical measurement methods that could be used for detection of micro- and nanoplastics.


Assuntos
Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Nanopartículas/análise , Plásticos/análise , Refratometria/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Poluentes Químicos da Água/análise
14.
J Optom ; 12(1): 22-29, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29580938

RESUMO

BACKGROUND: Accommodation is often recorded at a low sampling rate using devices such as autorefractors that are designed to measure the static refractive error. It is therefore important to determine if that resolution is sufficient to accurately measure the dynamic properties of accommodation. The current study provides both theoretical and empirical evidence on the ideal sampling rate necessary to measure a dynamic response. METHODS: Accommodative and disaccommodative step stimuli ranging from 1-3D (1D steps) were presented using a Badal optical system. Responses from 12 children (8-13 years) and 6 adults (20-35 years) were recorded using a dynamic photorefractor (DPR). Fast Fourier transformation was applied to the unsmoothed dynamic responses including position, velocity and acceleration. Also, velocity and acceleration main sequence (MS) characteristics were compared between three photorefractor conditions on 3 subjects. RESULTS: The Nyquist sampling limit necessary to accurately estimate position, velocity and acceleration was at least 5, 10 and 70Hz, respectively. Peak velocity and acceleration were significantly underestimated at a lower rate (p<0.5). However, the slope of MS remained invariant with sampling rate (p>0.5). CONCLUSION: Contrary to the previous findings, a dynamic accommodative response exhibited frequencies larger than 10Hz. Stimulus direction and amplitude had no influence on the frequencies present in the dynamic response. Peak velocity and acceleration can be significantly underestimated when sampled at a lower rate. Taken as a whole, low sampling rate instruments can accurately estimate static accommodation, however, caution needs to be exercised when using them for dynamic accommodation.


Assuntos
Acomodação Ocular/fisiologia , Optometria/métodos , Refratometria/métodos , Adolescente , Adulto , Criança , Feminino , Análise de Fourier , Humanos , Masculino , Optometria/instrumentação , Refração Ocular/fisiologia , Refratometria/instrumentação , Adulto Jovem
15.
Equine Vet J ; 51(4): 451-457, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30417417

RESUMO

BACKGROUND: Neonatal foals with failure of transfer of passive immunity (FTPI) are at higher risk of morbidity and mortality. Successful treatment of FTPI is time-dependent, thus rapid and accurate measurement of serum IgG concentration is important for the management and care of neonatal foals. OBJECTIVES: To validate the use of digital and optical refractometers for assessing FTPI in neonatal foals and compare the diagnostic performance and level of agreement of the two refractometers to the reference standard radial immunodiffusion (RID) assay. STUDY DESIGN: A retrospective validation study. METHODS: Serum samples (n = 253) were collected from 230 foals admitted to the Veterinary Teaching Hospital and Ambulatory Equine Service between 2012 and 2017. The serum IgG concentrations were measured by the reference RID assay, digital Brix and optical refractometers. The correlation between results of two refractometers and RID assay was assessed. A receiver operating characteristic curve was created and used to identify the optimal cut-offs for evaluating sensitivity and specificity of the two refractometers to detect foals with complete and partial FTPI. RESULTS: The RID-IgG concentrations were positively correlated with the Brix scores obtained from a digital refractometer (r = 0.73, P = 0.001) and serum total protein obtained from an optical refractometer (r = 0.72, P = 0.001). The sensitivity and specificity of the digital Brix refractometer at optimal cut-off (≤7.8% Brix) were 88.1 (95% CI: 74.4-96.0) and 67.7% (95% CI: 60.6-74.3) to detect RID-IgG<4 g/L and 79.0 (95% CI: 68.5-87.3) and 77.3% (95% CI: 69.8-83.8) to detect RID-IgG≤8 g/L, respectively. The sensitivity and specificity of the optical refractometer at optimal cut-off (≤42 g/L) were 86.1 (95% CI: 72.1-94.7) and 70.9% (95% CI: 63.9-77.3) to detect RID-IgG<4 g/L and at cut-off (≤44 g/L) were 82.9 (95% CI: 73.0-90.3) and 72.7% (95% CI: 64.8-79.6) to detect RID-IgG≤8 g/L, respectively. MAIN LIMITATIONS: The number of diseased foals was small to investigate the validity of the selected cut-off values for assessing FTPI in sick foals. CONCLUSIONS: The two refractometers exhibit utility as rapid, inexpensive screening tests and have a good sensitivity for assessing FTPI in neonatal foals.


Assuntos
Cavalos/sangue , Cavalos/imunologia , Imunidade Materno-Adquirida/fisiologia , Imunoglobulina G/sangue , Refratometria/veterinária , Animais , Animais Recém-Nascidos , Área Sob a Curva , Feminino , Imunodifusão/veterinária , Masculino , Refratometria/métodos , Estudos Retrospectivos , Sensibilidade e Especificidade
16.
Acta Vet Hung ; 66(4): 573-586, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30580538

RESUMO

Twenty-eight warmblood mares were monitored during their late pregnancy in the Teaching Hospital of Ghent University. The reliability of two commercial assays (enzyme immunoassay and glutaraldehyde coagulation test) used for determining the IgG concentrations of their newborn foals was tested. Mammary secretions were examined at the time of foaling (T0), and then 4 (T1) and 8 (T2) hours after foaling by refractometry and electrophoresis. The foals' blood IgG levels were measured at T1 and T2 as a routine clinical diagnostic examination using two different commercial test kits (SNAP Foal Ig and Gamma-Check E) and T0, T1 and T2 samples were stored (at -18 °C) for immunoglobulin (Ig) determination by electrophoresis. Differences between the results of refractometry and electrophoresis occurred in 27.8% of the colostrum analyses. Some serum IgG could be detected immediately post partum (T0) in 75% of the foals, and 42.82% of the newborn foals acquired a serum concentration of more than 800 mg/dl IgG within 8 h of birth. Compared to the electrophoresis, the glutaraldehyde test scored better (85%) than the enzyme immunoassay (74%), although both are accurate and safe to use since they clearly distinguish between safe and unsafe IgG concentrations.


Assuntos
Testes de Coagulação Sanguínea/veterinária , Testes Diagnósticos de Rotina/veterinária , Eletroforese/veterinária , Ensaio de Imunoadsorção Enzimática/veterinária , Refratometria/veterinária , Animais , Animais Recém-Nascidos , Testes de Coagulação Sanguínea/métodos , Colostro/química , Testes Diagnósticos de Rotina/métodos , Eletroforese/métodos , Ensaio de Imunoadsorção Enzimática/métodos , Glutaral/química , Cavalos , Imunoglobulina G/sangue , Refratometria/métodos , Reprodutibilidade dos Testes
17.
Rev Invest Clin ; 70(6): 310-318, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30532091

RESUMO

Background: Urine osmolarity (OsmU) is the gold standard for the evaluation of the kidney's urine concentration capacity; nevertheless, urinary density (UD) is often used as a surrogate for its estimation. Objective: The objective of this study was to analyze the accuracy of UD in estimating OsmU. Materials and Methods: A transversal study including patients with simultaneous determination of UD measured with refractometry and OsmU measured by osmometer (OsmUm). We multiplied the last two digits of the UD by 35, 30, 32, 33.5, and 40 to estimate OsmU; the estimates were considered precise if the value was ± 30 mOsm/kg from the OsmUm. A Bland-Altman analysis was conducted. Results: Among 205 patients, there was no difference between OsmUm and the estimated form when using a factor of 33.5 (p = 0.578). When analyzing by the absence or presence of proteinuria and/or glycosuria, there were no differences when using the factors 35 (p = 0.844) and 32 with adjusted UD (p = 0.898). In the linear correlation analysis, values for Pearson's r = 0.788 and r2 = 0.621 were obtained (p < 0.001). The areas under the curve obtained by the receiver operating characteristics curves to estimate urine osmolarity values < 100 and > 600 mOsm/kg were > 0.90. Conclusion: The estimation of the OsmU from UD showed adequate performance. If an osmometer is unavailable, we recommend using the factor 35 for clean samples and 32 with adjusted UD for samples with proteinuria and/or glycosuria.


Assuntos
Concentração Osmolar , Osmometria/métodos , Urinálise/métodos , Urina/química , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Glicosúria/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Proteinúria/epidemiologia , Refratometria/métodos , Reprodutibilidade dos Testes , Adulto Jovem
18.
Opt Express ; 26(20): 26520-26533, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469737

RESUMO

For the see-through and near-to-eye displays, light throughput and uniformity of luminance over the field of view are improved by employing an optical image guide with discretely depth-varying surface relief holographic gratings. In the design process, a newly developed mathematical model, in conjunction with rigorous coupled wave analysis of diffraction efficiency, eliminates massive and time consuming iteration of non-sequential ray tracing but rapidly identifies the depth-varying structure and optimum optical performance. The depth-varying grating based approach achieved a 1.37x improvement in light throughput compared to the conventional depth un-varying design, 315 cd/m2/lm, along with improved uniformity over the field of view of 35 (H) x 20 (V) degrees with an eye box size of 17 (H) x 14 (V) mm.


Assuntos
Simulação por Computador , Holografia/instrumentação , Modelos Teóricos , Algoritmos , Desenho de Equipamento , Holografia/métodos , Processamento de Imagem Assistida por Computador , Refratometria/métodos
19.
ACS Sens ; 3(11): 2223-2231, 2018 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-30380852

RESUMO

Aqueous solutions of alcohols are used in several applications, from pharmaceutics and biology, to chemical, biofuel, and food industries. Nonetheless, development of a simple, inexpensive, and portable sensing device for the quantification of water in water-ethanol mixtures remains a significant challenge. Photonic crystals (PhCs) operating at very high-order photonic bandgaps (PBGs) offer remarkable opportunities for the realization of chemical sensors with high sensitivity and low detection limit. However, high-order PhC structures have been mostly confined to mere theoretical speculations so far, their effective realization requiring microfabrication tools enabling the control of periodic refractive index modulations at the submicrometric scale with extremely high accuracy and precision. Here, we report both experimental and theoretical results on high-sensitivity chemical analysis using vertical, silicon/air 1D-PhCs with spatial period of 10 and 20 µm (namely, over 10 times the operation wavelength) featuring ultra-high-order PBGs in the near-infrared region (namely, up to 50th at 1.1 µm). Fabrication of high-order 1D-PhCs was carried out by electrochemical micromachining (ECM) of silicon, which allowed both surface roughness and deviation from vertical of etched structures to be controlled below 5 nm and 0.1%, respectively. Optical characterization of ECM-fabricated 1D-PhCs, which was performed by acquiring reflectivity spectra over the wavelength range 1-1.7 µm, highlighted the presence of ultra-high-order PBGs with minor optical losses (i.e., <1 dB in reflectivity) separated by deep reflectivity notches with high Q-factors (i.e., >6000), in good agreement with theoretical calculations. Remarkably, the use of high-order 1D-PhCs as refractometric transducers for the quantitative detection of traces of water in water-ethanol mixtures, allowed high sensitivity (namely, either 1000 nm/RIU or ∼0.4 nm/% of water), good detection limit (namely, 5 × 10-3 RIU or ∼10% water), and excellent resolution (namely, either 6 × 10-4 RIU or 1.6% of water) to be reliably achieved on a detection volume of about 168 fL.


Assuntos
Etanol/química , Silício/química , Água/análise , Calibragem , Luz , Limite de Detecção , Microtecnologia , Refratometria/instrumentação , Refratometria/métodos , Silício/efeitos da radiação , Transdutores , Água/química
20.
Prev Vet Med ; 159: 182-195, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30314781

RESUMO

The study objectives were to: 1) evaluate the diagnostic performance of passive immunity tests for classification of failure of passive transfer (FPT) risk, based on their relationships with calf health and performance, and 2) describe the epidemiology of morbidity and mortality in suckler beef and dairy calves under Irish conditions. A total of 1392 suckler beef calves (n = 111 farms) and 2090 dairy calves (84 farms) were included in this observational study. Blood samples were collected by jugular venipuncture. Serum samples were analysed for total IgG concentration using an ELISA assay, total protein concentration by clinical analyser (TP - CA), globulin concentration, zinc sulphate turbidity (ZST) units, total solids percentage by Brix refractometer (TS - BRIX), and total protein concentration by digital refractometer (TP - DR). Crude and cause-specific morbidity, all-cause mortality, and standardised 205-day body weight (BW) were determined. Generalised linear mixed models were used to evaluate associations between suckler beef and dairy calves for morbidity, mortality, growth and passive immunity. Receiver operating characteristic (ROC) curves were constructed to determine optimal test cut-offs for classification of health and growth outcomes. Overall, 20% of suckler beef and 30% of dairy calves were treated for at least one disease event by 6 mo. of age. Suckler beef calves had greater odds of bovine respiratory disease (BRD; odds ratio (OR), 95% confidence interval (CI): 2.8, 1.2-6.5, P = 0.01), navel infection (5.1, 1.9-13.2, P < 0.001), and joint infection/lameness (3.2, 1.3-7.8, P = 0.01) during the first 6 mo. of life than dairy calves. In addition, from birth to 6 mo. of age, suckler beef calves had greater rates of navel infection (incidence rate ratio (IRR), 95% CI: 3.3, 1.3-8.4, P = 0.01), but decreased rates of diarrhoea (0.9, 0.2-0.9, P = 0.03) compared to dairy calves. Optimal test cut-offs for classification of morbidity and mortality outcomes in suckler beef calves ranged from 8 to 9 mg/ml ELISA, 56 to 61 g/l TP - CA, 26 to 40 g/l globulin, 12 to 18 ZST units, 8.4% TS - BRIX, and 5.3 to 6.3 g/dl TP - DR. Optimal test cut-offs for classification of morbidity and growth outcomes in dairy calves ranged from 10 to 12 mg/ml ELISA, 57 to 60 g/l TP - CA, 29 to 34 g/l globulin, 19 ZST units, 7.8 to 8.4% TS - BRIX, and 5.7 to 5.9 g/dl TP - DR.


Assuntos
Doenças dos Bovinos/mortalidade , Bovinos/imunologia , Ensaio de Imunoadsorção Enzimática/veterinária , Imunidade Materno-Adquirida/imunologia , Refratometria/veterinária , Animais , Animais Recém-Nascidos/imunologia , Doenças dos Bovinos/etiologia , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Irlanda/epidemiologia , Masculino , Morbidade , Mortalidade , Refratometria/métodos
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