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1.
Talanta ; 206: 120207, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514857

RESUMO

Herein, a multicommuted flow-batch setup and a photometric procedure for the determination of mercury at the ppb level in aqueous samples are described. The setup was designed to implement a versatile solvent extraction and pre-concentration strategy by combining flow-batch and multicommuted flow analysis approaches. The photometric method was based on Hg(II) reaction with dithizone in a chloroform medium, which was also used as the extracting organic solvent. The flow analysis system was composed of a homemade syringe pump module, a set of solenoid valves, two Aquarius mini-pumps, and a flow-batch chamber. The homemade photometer was comprised of a light emitting diode (LED), photodiode, and homemade flow cell (50 mm length). The flow system and photometer were controlled using an Arduino Due board, running custom-written software. After optimizing the operational conditions, the effectiveness of the developed system was evaluated for the determination of the mercury concentration in drinking water. For accuracy assessment, samples were analyzed using a spiking methodology and an independent method, yielding a recovery ranging from 92% to 108%. Other important characteristics of the proposed method were found as follows: linear response range, 0.5-10.0 µg L-1 (r = 0.9984); limit of detection 0.38 µg L-1 Hg(II); consumption of dithizone and chloroform, 1.85 µg L-1 and 0.8 mL per analysis, respectively; coefficient of variation, 2% (n = 10); sampling throughput, 20 determinations per h.


Assuntos
Água Potável/análise , Mercúrio/análise , Fotometria/métodos , Poluentes Químicos da Água/análise , Clorofórmio/química , Ditizona/química , Química Verde/instrumentação , Química Verde/métodos , Limite de Detecção , Águas Minerais/análise , Fotometria/instrumentação , Rios/química
2.
Nat Methods ; 16(11): 1185-1192, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31591577

RESUMO

Fiber photometry is increasingly utilized to monitor fluorescent sensors of neural activity in the brain. However, most implementations are based on flat-cleaved optical fibers that can only interface with shallow tissue volumes adjacent to the fiber. We exploit modal properties of tapered optical fibers (TFs) to enable light collection over an extent of up to 2 mm of tissue and multisite photometry along the taper. Using a single TF, we simultaneously observed distinct dopamine transients in dorsal and ventral striatum in freely moving mice performing a simple, operant conditioning task. Collection volumes from TFs can also be engineered in both shape and size by microstructuring the nonplanar surface of the taper, to optically target multiple sites not only in the deep brain but, in general, in any biological system or organ in which light collection is beneficial but challenging because of light scattering and absorption.


Assuntos
Fibras Ópticas , Fotometria/métodos , Animais , Corpo Estriado/metabolismo , Dopamina/metabolismo , Fluorescência , Masculino , Camundongos , Camundongos Endogâmicos C57BL
3.
Molecules ; 24(18)2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31547318

RESUMO

The analysis of volatile sulfur compounds using headspace solid-phase microextraction (HS-SPME) is heavily influenced by matrix effects. The effects of a wine matrix, both non-volatile and volatile components (other than ethanol) were studied on the analysis of several common sulfur volatiles found in wine, including hydrogen sulfide (H2S), methanethiol (MeSH), dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), diethyl disulfide (DEDS), methyl thioacetate (MeSOAc), and ethyl thioacetate (EtSOAc). Varying levels of devolatilized wine and common wine volatiles (acids, esters, alcohols) were added to synthetic wine samples to act as matrices. Sulfur standards were added and analyzed using gas chromatography with pulsed-flame photometric detection (GC-PFPD). Five internal standards were used to find best representatives of each compound despite matrix effects. Sensitivity remained stable with the addition of devolatilized wine, while addition of volatile components decreased sensitivity. DMS was found to be best measured against EMS; DMDS and the thioacetates were best measured against DES; H2S, MeSH, DEDS, and DMTS were best measured against DIDS. The method was used to quantitate the volatile sulfur compounds in 21 wines with various ethanol contents and volatile profiles.


Assuntos
Microextração em Fase Sólida/métodos , Compostos de Enxofre/análise , Compostos Orgânicos Voláteis/análise , Vinho/análise , Cromatografia Gasosa/métodos , Dissulfetos/análise , Análise de Alimentos/métodos , Sulfeto de Hidrogênio/análise , Fotometria/métodos , Sensibilidade e Especificidade , Compostos de Sulfidrila/análise , Sulfetos/análise , Compostos de Enxofre/química , Compostos Orgânicos Voláteis/química
4.
Molecules ; 24(14)2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31295807

RESUMO

The rate-limiting enzyme of the 2-methyl-d-erythritol-4-phosphate (MEP) terpenoid biosynthetic pathway, 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), provides the perfect target for screening new antibacterial substances. In this study, we tested the DXR inhibitory effect of 35 plant essential oils (EOs), which have long been recognized for their antimicrobial properties. The results show that the EOs of Zanbthoxylum bungeanum (ZB), Schizonepetae tenuifoliae (ST), Thymus quinquecostatus (TQ), Origanum vulgare (OV), and Eugenia caryophyllata (EC) displayed weak to medium inhibitory activity against DXR, with IC50 values of 78 µg/mL, 65 µg/mL, 59 µg/mL, 48 µg/mL, and 37 µg/mL, respectively. GC-MS analyses of the above oils and further DXR inhibitory activity tests of their major components revealed that eugenol (EC) and carvacrol (TQ and OV) possess medium inhibition against the protein (68.3% and 55.6%, respectively, at a concentration of 20 µg/mL), whereas thymol (ST, TQ, and OV), carveol (ZB), and linalool (ZB, ST, and OV) only exhibited weak inhibition against DXR, at 20 µg/mL (23%-26%). The results add more details to the antimicrobial mechanisms of plant EOs, which could be very helpful in the direction of the reasonable use of EOs in the food industry and in the control of phytopathogenic microbials.


Assuntos
Aldose-Cetose Isomerases/antagonistas & inibidores , Antibacterianos/farmacologia , Inibidores Enzimáticos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Antibacterianos/química , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/química , Cromatografia Gasosa-Espectrometria de Massas , Estrutura Molecular , Óleos Voláteis/química , Fotometria/métodos , Óleos Vegetais/química
5.
Graefes Arch Clin Exp Ophthalmol ; 257(10): 2323-2328, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31300898

RESUMO

PURPOSE: Irradiation of choroidal melanoma is a safe and globe preserving procedure. Chronic inflammatory processes and ischemia are the main reasons for secondary enucleation in the long run. The aim of this study was to determine whether intraocular inflammation and especially inflammatory response after proton beam therapy (PBT) is related to primary tumor characteristics such as height, tumor volume, and initial flare values. METHODS: Twenty-six patients treated for uveal melanoma using PBT were included. All patients were examined for signs of inflammation using laser flare photometry (LFP). Each examination included assessment of the melanoma and fellow eye (which acted as the control) and imaging of the melanoma. RESULTS: Significant differences of flare values between melanoma eyes and control group were found both at baseline (median 17.65 ph/ms (min 4, max 37.10), 7.45 ph/ms (min 0.80, max 16.40), respectively) and during follow-up (median 21.45 ph/ms (min 4.5, max 70.90); 6.05 ph/ms (min 2.40, max 16.40), respectively) (p < 0.001, Wilcoxon test). Flare values in melanoma eyes increased significantly after PBT (p = 0.005, Wilcoxon test) and after a follow-up of 94 days (median, 7-420 days). Flare values of the control group did not change (p = 0.946, Wilcoxon test). The increase of flare values correlated significantly with maximum tumor height and volume (Spearman-Rho 0.633, p = 0.001 and 0.519, p = 0.007, respectively). CONCLUSION: LFP has proven to show significantly higher flare values in melanoma eyes as compared with the control group and provides data on the course of the inflammatory response after treatment. It may ease treatment planning both at baseline and during follow-up.


Assuntos
Humor Aquoso/metabolismo , Barreira Hematoaquosa/fisiologia , Neoplasias da Coroide/radioterapia , Melanoma/radioterapia , Acuidade Visual , Adulto , Idoso , Humor Aquoso/efeitos da radiação , Neoplasias da Coroide/diagnóstico , Neoplasias da Coroide/metabolismo , Feminino , Angiofluoresceinografia , Seguimentos , Fundo de Olho , Humanos , Masculino , Melanoma/diagnóstico , Melanoma/metabolismo , Pessoa de Meia-Idade , Fotometria/métodos , Terapia com Prótons , Estudos Retrospectivos , Tomografia de Coerência Óptica , Resultado do Tratamento
6.
Talanta ; 204: 586-591, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31357338

RESUMO

A simple, small and inexpensive photometer that uses a pair of light-emitting diodes (LEDs) and a simple operational amplifier was developed for investigating thiocyanate levels in saliva obtained from smokers and non-smokers. The photometer is based on paired emitter-detector diodes (PEDDs), and the entire system can be purchased for less than a hundred US dollars. The PEDD-based photometer can measure the transmittance of a solution in a 1-cm disposable polystyrene cuvette using only rechargeable dry-cell batteries, which makes it suitable for analysis outside of equipped laboratories. The metal complex formation between Fe (III) and thiocyanate ions in an acidic condition permits colorimetric detection of thiocyanate ions using LEDs emitting at 465 nm, because the complex shows maximum absorption at 457 nm. The developed photometer exhibits excellent performance with linearity ranging from 0.05 mmol L-1 to 0.75 mmol L-1 and a correlation coefficient (r2) > 0.999. The limits of detection and quantification were 0.01 mmol L-1 and 0.05 mmol L-1, respectively. Both intra- and inter-day precision were obtained with relative standard deviations (RSD) of less than 1% in the determination of thiocyanate. The proposed method is simple, facile, and sensitive enough to investigate the levels of thiocyanate in the saliva samples of smokers and non-smokers with centrifugation being the only special treatment for samples. The results showed that the concentrations of thiocyanate were approximately 5-fold higher in smokers than in non-smokers.


Assuntos
Saliva/química , Tiocianatos/análise , Colorimetria/instrumentação , Colorimetria/métodos , Humanos , Ferro/análise , Iluminação/instrumentação , Limite de Detecção , não Fumantes , Fotometria/instrumentação , Fotometria/métodos , Reprodutibilidade dos Testes , Fumantes
7.
Nat Methods ; 16(6): 553-560, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31086339

RESUMO

Animal behavior originates from neuronal activity distributed across brain-wide networks. However, techniques available to assess large-scale neural dynamics in behaving animals remain limited. Here we present compact, chronically implantable, high-density arrays of optical fibers that enable multi-fiber photometry and optogenetic perturbations across many regions in the mammalian brain. In mice engaged in a texture discrimination task, we achieved simultaneous photometric calcium recordings from networks of 12-48 brain regions, including striatal, thalamic, hippocampal and cortical areas. Furthermore, we optically perturbed subsets of regions in VGAT-ChR2 mice by targeting specific fiber channels with a spatial light modulator. Perturbation of ventral thalamic nuclei caused distributed network modulation and behavioral deficits. Finally, we demonstrate multi-fiber photometry in freely moving animals, including simultaneous recordings from two mice during social interaction. High-density multi-fiber arrays are versatile tools for the investigation of large-scale brain dynamics during behavior.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Tecnologia de Fibra Óptica/métodos , Neurônios/fisiologia , Optogenética , Fotometria/métodos , Proteínas Vesiculares de Transporte de Aminoácidos Inibidores/fisiologia , Animais , Comportamento Animal , Encéfalo/citologia , Sinalização do Cálcio , Tecnologia de Fibra Óptica/instrumentação , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/citologia
8.
Gigascience ; 8(5)2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31127811

RESUMO

BACKGROUND: Tracking and predicting the growth performance of plants in different environments is critical for predicting the impact of global climate change. Automated approaches for image capture and analysis have allowed for substantial increases in the throughput of quantitative growth trait measurements compared with manual assessments. Recent work has focused on adopting computer vision and machine learning approaches to improve the accuracy of automated plant phenotyping. Here we present PS-Plant, a low-cost and portable 3D plant phenotyping platform based on an imaging technique novel to plant phenotyping called photometric stereo (PS). RESULTS: We calibrated PS-Plant to track the model plant Arabidopsis thaliana throughout the day-night (diel) cycle and investigated growth architecture under a variety of conditions to illustrate the dramatic effect of the environment on plant phenotype. We developed bespoke computer vision algorithms and assessed available deep neural network architectures to automate the segmentation of rosettes and individual leaves, and extract basic and more advanced traits from PS-derived data, including the tracking of 3D plant growth and diel leaf hyponastic movement. Furthermore, we have produced the first PS training data set, which includes 221 manually annotated Arabidopsis rosettes that were used for training and data analysis (1,768 images in total). A full protocol is provided, including all software components and an additional test data set. CONCLUSIONS: PS-Plant is a powerful new phenotyping tool for plant research that provides robust data at high temporal and spatial resolutions. The system is well-suited for small- and large-scale research and will help to accelerate bridging of the phenotype-to-genotype gap.


Assuntos
Aprendizado Profundo , Imagem Tridimensional/métodos , Fotometria/métodos , Desenvolvimento Vegetal , Arabidopsis , Imagem Tridimensional/economia , Imagem Tridimensional/normas , Fenótipo , Fotometria/economia , Fotometria/normas
9.
Neurosci Bull ; 35(3): 425-433, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31062336

RESUMO

Fiber photometry is a sensitive and easy way to detect changes in fluorescent signals. The combination of fiber photometry with various fluorescent biomarkers has substantially advanced neuroscience research over the last decade. Despite the wide use of fiber photometry in biomedical fields, the lack of a detailed and comprehensive protocol has limited progress and sometimes complicated the interpretation of data. Here, we describe detailed procedures of fiber photometry for the long-term monitoring of neuronal activity in freely-behaving animals, including surgery, apparatus setup, data collection, and analysis.


Assuntos
Encéfalo/metabolismo , Sinalização do Cálcio , Neurônios/metabolismo , Imagem Óptica/métodos , Fotometria/métodos , Animais , Feminino , Masculino , Camundongos , Procedimentos Neurocirúrgicos , Fibras Ópticas , Imagem Óptica/instrumentação , Fotometria/instrumentação
10.
Appl Spectrosc ; 73(1): 104-114, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30012006

RESUMO

The use of rotating filter wheels is common in photometric applications. Traditional filter wheel designs typically exhibit a number of filter openings spaced evenly about the circumference of the wheel. In this work we examine a number of shortcomings of this traditional filter design in measurements of phytoplankton fluorescence made with our fluorescence imaging photometer (FIP). We present an alternative asymmetric wheel design that offers a number of advantages over the traditional design as well as a new processing algorithm designed to accommodate convolution of signals from adjacent channels inherent in measurements collected with the asymmetric design. This approach eliminates the need for a separate signal to establish timing and wheel position, unambiguously establishes filter order even when the direction of rotation is unknown, allows for better estimates of signal baseline, and is more resilient to effects of vibration and other dynamic processes that could occur on the time scale of wheel rotation. We demonstrate performance improvements for phytoplankton fluorescence measurements associated with the new wheel design and algorithm compared with previously published methods using the FIP. Both the improved image processing algorithm and filter wheel design were found to reduce noise in our measurements significantly.


Assuntos
Algoritmos , Processamento de Imagem Assistida por Computador/métodos , Imagem Óptica/métodos , Fitoplâncton , Desenho de Equipamento , Microscopia de Fluorescência/instrumentação , Microscopia de Fluorescência/métodos , Imagem Óptica/instrumentação , Fotometria/instrumentação , Fotometria/métodos , Fitoplâncton/química , Fitoplâncton/citologia
11.
J Anal Toxicol ; 43(1): 36-44, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30060005

RESUMO

Tris(chloropropyl)phosphate (TCPP) is an organophosphorus flame retardant (OPFR) and plasticizer increasingly used in consumer products and as a replacement for brominated flame retardants. Commercially available TCPP is a mixture of four structural isomers the most abundant of which is tris(1-chloro-2-propyl)phosphate (TCPP-1). Although there is a widespread use of TCPP and potential for human exposure, there is limited data on the safety or toxicity of TCPP. The National Toxicology Program is conducting long-term studies to examine the toxicity of the TCPP in rats after lifetime exposure, including perinatal oral exposure. Quantitative estimates of internal dose are essential to interpret toxicological findings in rodents. To aid in this, a method was fully validated to quantitate the most abundant isomer, TCPP-1, in female Harlan Sprague Dawley (HSD) rat and B6C3F1 mouse plasma with partial validation in male rat plasma, and male and female mouse plasma. The method used protein precipitation using trichloroacetic acid followed by the extraction with toluene, and analysis by gas chromatography with flame photometric detection. The performance of the method was evaluated over 5-70 ng TCPP-1/mL plasma. The method was linear (r ≥ 0.99), accurate (inter-day relative error: ≤ ± -7.2) and precise (inter-batch relative standard deviation: ≤27.5%). The validated method has lower limits of quantitation and detection of ~5 and 0.9 ng/mL, respectively, in female HSD rat plasma and can be used on samples as small as 50 µL demonstrating the applicability to plasma samples from toxicology studies.


Assuntos
Cromatografia Gasosa/métodos , Retardadores de Chama/análise , Organofosfatos/sangue , Fotometria/métodos , Plastificantes/análise , Animais , Calibragem , Cromatografia Gasosa/normas , Feminino , Ionização de Chama , Limite de Detecção , Masculino , Camundongos , Fotometria/normas , Ratos Sprague-Dawley , Padrões de Referência , Reprodutibilidade dos Testes
12.
Ocul Immunol Inflamm ; 27(4): 651-657, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30205420

RESUMO

Purpose: The purpose of the study is to quantify aqueous flare using laser flare photometry (LFM) in patients undergoing 25-G pars plana vitrectomy (PPV) and assess the need for postoperative topical corticosteroid administration . Methods: Prospective evaluation of 50 eyes (50 patients) was performed using LFM until day 30 postoperative. Duration of surgery, indication of PPV, and use of laser and/or cryotherapy were noted. Topical corticosteroids were used if mean LFM values were >50, or if there was anterior chamber fibrin. Results: Mean age of the subjects was 48.62 ± 10.07 years. The preoperative LFM value for 50 subjects was 17.42 ± 25.20. Topical corticosteroids were initiated in only 22 patients. The LFM values of subjects were not different from baseline at 1 month whether or not the subjects received corticosteroids (p > 0.106). Conclusions: With 25-G PPV, there is minimal breakdown of blood-aqueous barrier. LFM helps in monitoring postoperative inflammation, obviating the need for topical corticosteroids in significant number of patients.


Assuntos
Humor Aquoso/fisiologia , Barreira Hematoaquosa/fisiologia , Microcirurgia/métodos , Fotometria/métodos , Doenças Retinianas/cirurgia , Vitrectomia/métodos , Adolescente , Adulto , Humor Aquoso/diagnóstico por imagem , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Valor Preditivo dos Testes , Estudos Prospectivos , Doenças Retinianas/metabolismo , Acuidade Visual , Adulto Jovem
13.
J Chromatogr A ; 1583: 19-27, 2019 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-30442472

RESUMO

In this work, magnetic nanoporous carbons (MNPCs) based on Zn/Co-MOFs was synthesized via a facial one-step carbonization method. The prepared MNPCs exhibited high specific surface areas, good chemical stability and high extraction efficiency for interest organophosphorus pesticides (OPPs). The good extraction performance of the MNPCs for interest OPPs can be primarily attributed to π-π interaction and hydrophobic interaction between MNPCs and OPPs. Based on it, MNPCs-based MSPE-GC-FPD method was established for the quantification of five OPPs in fruit samples. The main experimental conditions for MSPE of five target OPPs were investigated systematically and optimized, such as the desorption solvent and volume, extracted volume, ionic strength, extraction time and desorption time. Under the optimal conditions, the limits of detection (LODs, S/N = 3) were found to be in the range of 0.018 (ethion) -0.045 (malathion) µg/L. The linearity was 0.05-100 µg/L for phorate, diazinon, ethion and 0.1-100 µg/L for malathion, fenthion respectively. The reproducibility of the method was in the range of 3.5-9.7%. The recovery experiments were carried out by spiking target OPPs at three concentration levels to validate the accuracy of the proposed method, and the recoveries for target OPPs were 84-116%. The results show that the proposed method in this work can be successfully used to analyze OPPs residue in fruit sample.


Assuntos
Carbono/química , Cromatografia Gasosa/métodos , Frutas/química , Estruturas Metalorgânicas/química , Nanoporos , Compostos Organofosforados/análise , Praguicidas/análise , Fotometria/métodos , Limite de Detecção , Fenômenos Magnéticos , Metanol/química , Compostos Organotiofosforados/análise , Concentração Osmolar , Resíduos de Praguicidas/análise , Reprodutibilidade dos Testes , Extração em Fase Sólida , Solventes/química , Fatores de Tempo
14.
Neuron ; 101(1): 133-151.e7, 2019 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-30503173

RESUMO

Ventral tegmental area (VTA) dopamine (DA) neurons play a central role in mediating motivated behaviors, but the circuitry through which they signal positive and negative motivational stimuli is incompletely understood. Using in vivo fiber photometry, we simultaneously recorded activity in DA terminals in different nucleus accumbens (NAc) subnuclei during an aversive and reward conditioning task. We find that DA terminals in the ventral NAc medial shell (vNAcMed) are excited by unexpected aversive outcomes and to cues that predict them, whereas DA terminals in other NAc subregions are persistently depressed. Excitation to reward-predictive cues dominated in the NAc lateral shell and was largely absent in the vNAcMed. Moreover, we demonstrate that glutamatergic (VGLUT2-expressing) neurons in the lateral hypothalamus represent a key afferent input for providing information about aversive outcomes to vNAcMed-projecting DA neurons. Collectively, we reveal the distinct functional contributions of separate mesolimbic DA subsystems and their afferent pathways underlying motivated behaviors. VIDEO ABSTRACT.


Assuntos
Aprendizagem da Esquiva/fisiologia , Neurônios Dopaminérgicos/metabolismo , Sistema Límbico/metabolismo , Rede Nervosa/metabolismo , Área Tegmentar Ventral/metabolismo , Animais , Sistema Límbico/citologia , Masculino , Mesencéfalo/citologia , Mesencéfalo/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Rede Nervosa/citologia , Técnicas de Cultura de Órgãos , Fotometria/métodos , Área Tegmentar Ventral/citologia , Proteína Vesicular 2 de Transporte de Glutamato/biossíntese
16.
Science ; 362(6413): 429-434, 2018 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-30361367

RESUMO

Clinical observations indicate that the paramedian region of the thalamus is a critical node for controlling wakefulness. However, the specific nucleus and neural circuitry for this function remain unknown. Using in vivo fiber photometry or multichannel electrophysiological recordings in mice, we found that glutamatergic neurons of the paraventricular thalamus (PVT) exhibited high activities during wakefulness. Suppression of PVT neuronal activity caused a reduction in wakefulness, whereas activation of PVT neurons induced a transition from sleep to wakefulness and an acceleration of emergence from general anesthesia. Moreover, our findings indicate that the PVT-nucleus accumbens projections and hypocretin neurons in the lateral hypothalamus to PVT glutamatergic neurons' projections are the effector pathways for wakefulness control. These results demonstrate that the PVT is a key wakefulness-controlling nucleus in the thalamus.


Assuntos
Núcleos da Linha Média do Tálamo/fisiologia , Vigília/fisiologia , Animais , Eletrofisiologia/métodos , Feminino , Ácido Glutâmico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Neurônios/fisiologia , Núcleo Accumbens/fisiologia , Optogenética , Orexinas/genética , Fotometria/métodos , Proteínas Proto-Oncogênicas c-fos/metabolismo
17.
Talanta ; 190: 193-198, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30172498

RESUMO

In this contribution a highly cost-effective flow analysis system for determination of alkaline phosphatase (ALP) activity is presented. This fully-mechanized bioanalytical system is based on economic solenoid micropumps and microvalves (powered and actuated by Arduino microcontroller) and extremely cheap dedicated optoelectronic flow-through detectors allowing absorbance and fluorescence measurements. The detection schemes for ALP assaying realized in this system are based on orthophosphate determination. For the detection of these ions formed in the course of enzymatic conversion a molybdate method requiring only common and inexpensive chemicals is utilized. Thus, for the enzymatic assays the simplest not-chromogenic/not-fluorogenic ALP substrates can be applied. Such approach results in the use of low-cost reagents for ALP assays, whereas the mechanization of assay causes low consumption of reagents as well as samples. In the course of reported investigations six ALP substrates were examined and the most promising results have been obtained for the inorganic compound - monofluorophosphate (MFP). The obtained linear ranges of absorbance and fluorescence measurements are 100-600 U L-1 and 30-30/30-100 U L-1, with sensitivities of 0.7 mV L-1 U-1 and 2.3/1.0 mV L-1 U-1, respectively. The calculated limits of detection are 5.1 U L-1 (photometry) and 0.9 U L-1 (fluorometry). The throughputs of the developed system are 13 and 12 samples/h for photometric and fluorometric detections, respectively. To demonstrate the practical utility of the developed bioanalytical system the ALP assays in complex matrix samples have been carried out. The results of ALP activity determination in serum samples are well-correlated with those obtained using reference method recommended for routine clinical analysis.


Assuntos
Fosfatase Alcalina/metabolismo , Ensaios Enzimáticos/métodos , Fluorometria/métodos , Fotometria/métodos , Fosfatos/metabolismo
18.
J Agric Food Chem ; 66(33): 8859-8863, 2018 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-30067024

RESUMO

Adulterating edible oil with copper chlorophyll derivatives (E141i) has made a substantial impact on the edible oil industry and food safety. This study demonstrates an efficient and reliable screening method to directly identify the color adulteration by the aid of a simple photobleaching pretreatment using a 365 nm ultraviolet-light-emitting diode working at a photon flux density of 480 mmol m-2 s-1 for 24 min. The content of copper chlorophyll [predominantly Cu-pyropheophytin a (Cu-py a)] can be calculated by A600, A650, and A700 with satisfactory spike recovery [97.9-103.6%; six kinds of edible oils spiked with 1 ppm of Cu-py a; n = 3 for each kind of oil; relative standard deviation (RSD) < 5%], linearity ( R2 = 0.9961 when spiking 0.1-10 ppm of Cu-py a into soybean oil standard; n = 3 for each concentration; RSD < 5%), and reproducibility (RSD < 5% for spiking 1 ppm of Cu-py a into soybean oil standard; n = 3 over 3 days). The detection limit (S/N > 5) was 0.05 ppm. The analytical results of 50 commercially available oil samples were verified by the official high-performance liquid chromatography method.


Assuntos
Clorofilídios/análise , Cobre/análise , Contaminação de Alimentos/análise , Fotometria/métodos , Óleos Vegetais/análise , Fotodegradação/efeitos dos fármacos
19.
IEEE Trans Biomed Circuits Syst ; 12(3): 495-509, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29877814

RESUMO

Fluorescence biophotometry measurements require wide dynamic range (DR) and high-sensitivity laboratory apparatus. Indeed, it is often very challenging to accurately resolve the small fluorescence variations in presence of noise and high-background tissue autofluorescence. There is a great need for smaller detectors combining high linearity, high sensitivity, and high-energy efficiency. This paper presents a new biophotometry sensor merging two individual building blocks, namely a low-noise sensing front-end and a order continuous-time modulator (CTSDM), into a single module for enabling high-sensitivity and high energy-efficiency photo-sensing. In particular, a differential CMOS photodetector associated with a differential capacitive transimpedance amplifier-based sensing front-end is merged with an incremental order 1-bit CTSDM to achieve a large DR, low hardware complexity, and high-energy efficiency. The sensor leverages a hardware sharing strategy to simplify the implementation and reduce power consumption. The proposed CMOS biosensor is integrated within a miniature wireless head mountable prototype for enabling biophotometry with a single implantable fiber in the brain of live mice. The proposed biophotometry sensor is implemented in a 0.18- CMOS technology, consuming from a 1.8- supply voltage, while achieving a peak dynamic range of over a 50- input bandwidth, a sensitivity of 24 mV/nW, and a minimum detectable current of 2.46- at a 20- sampling rate.


Assuntos
Técnicas Biossensoriais , Fotometria , Tecnologia sem Fio/instrumentação , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Humanos , Fotometria/instrumentação , Fotometria/métodos
20.
J Clin Lab Anal ; 32(9): e22594, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29921038

RESUMO

BACKGROUND: Hydroelectrolytic disorders are common in clinical situations and may be harmful to the patient, especially those involving plasma sodium and potassium dosages. Among the possible methods for the dosages are flame photometry, ion-selective electrode (ISE) and colorimetric enzymatic method. METHODS: We analyzed 175 samples in the three different methods cited from patients attending the laboratory of the University Hospital of the Federal University of Juiz de Fora. The values obtained were statistically treated using SPSS 19.0 software. The present study aims to evaluate the impact of the use of these different methods in the determination of plasma sodium and potassium. RESULTS: The averages obtained for sodium and potassium measurements by flame photometry were similar (P > .05) to the means obtained for the two electrolytes by ISE. The averages obtained by the colorimetric enzymatic method presented statistical difference in relation to ISE, both for sodium and potassium. In the correlation analysis, both flame photometry and colorimetric enzymatic showed a strong correlation with the ISE method for both dosages. CONCLUSION: At the first time in the same work sodium and potassium were analyzed by three different methods and the results allowed us to conclude that the methods showed a positive and strong correlation, and can be applied in the clinical routine.


Assuntos
Colorimetria/métodos , Fotometria/métodos , Potássio/sangue , Sódio/sangue , Adolescente , Adulto , Idoso , Correlação de Dados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Potássio/análise , Sódio/análise , Adulto Jovem
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