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1.
J Synchrotron Radiat ; 31(Pt 2): 399-408, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38335147

RESUMO

X-ray ptychography is a coherent diffraction imaging technique based on acquiring multiple diffraction patterns obtained through the illumination of the sample at different partially overlapping probe positions. The diffraction patterns collected are used to retrieve the complex transmittivity function of the sample and the probe using a phase retrieval algorithm. Absorption or phase contrast images of the sample as well as the real and imaginary parts of the probe function can be obtained. Furthermore, X-ray ptychography can also provide spectral information of the sample from absorption or phase shift images by capturing multiple ptychographic projections at varying energies around the resonant energy of the element of interest. However, post-processing of the images is required to extract the spectra. To facilitate this, ProSPyX, a Python package that offers the analysis tools and a graphical user interface required to process spectral ptychography datasets, is presented. Using the PyQt5 Python open-source module for development and design, the software facilitates extraction of absorption and phase spectral information from spectral ptychographic datasets. It also saves the spectra in file formats compatible with other X-ray absorption spectroscopy data analysis software tools, streamlining integration into existing spectroscopic data analysis pipelines. To illustrate its capabilities, ProSPyX was applied to process the spectral ptychography dataset recently acquired on a nickel wire at the SWING beamline of the SOLEIL synchrotron.

2.
Rev. andal. med. deporte ; 16(3-4)dic.-2023. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-ADZ-351

RESUMO

Objetivo: Las restricciones de salud pública por el COVID-19 han jugado un papel central en la gestión de los programas de entrenamiento, en los que son escasos los estudios enfocados en la cuantificación de las cargas de entrenamiento en pretemporada, especialmente en futbolistas jóvenes. Por lo tanto, este estudio monitoreó la carga de entrenamiento interno (CEI) durante la pretemporada 2020/2021 durante la pandemia de COVID-19 de los jugadores de fútbol Sub-20. Método: Catorce futbolistas Sub-20 fueron monitoreados durante 7 semanas durante la pretemporada 2020/2021. El CEI de todas las sesiones de entrenamiento se estimó, en unidades arbitrarias, multiplicando el índice de esfuerzo percibido (IEP) para la sesión de entrenamiento completa por la duración de cada sesión de entrenamiento en minutos (IEP-sesión). También se estimaron la monotonía y la tensión de entrenamiento. Un ANOVA unidireccional de medidas repetidas comparó las variables dependientes a lo largo del tiempo. Resultados: En la cuarta semana, la CEI y la tensión de entrenamiento fueron estadísticamente más bajas en comparación con las otras semanas (P<0,05). El índice de monotonía de la semana 7 fue mayor en comparación con las semanas 1, 3 y 4 (P<0,05). Conclusión: Las restricciones sanitarias por el COVID-19 han afectado negativamente la carga de entrenamiento de pretemporada de los futbolistas Sub-20. Sin embargo, el índice de monotonía mostró que las cargas de entrenamiento estaban bien distribuidas durante las 7 semanas. (AU)


Assuntos
Humanos , Atletas , Vigilância em Desastres , Futebol , Desempenho Atlético , Saúde Pública
4.
Theriogenology ; 170: 77-84, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34000520

RESUMO

Since buffaloes are a seasonal, polyestrous species, optimizing reproduction during the non-breeding season is a key factor in increasing the reproductive and productive efficiency of herds. Ovum pick-up associated with in vitro embryo production and embryo cryopreservation is an alternative to reduce seasonal impacts. We studied the effects of seasonality in buffalo oocyte donors and embryo recipients during the favorable and non-favorable breeding seasons. Donors were evaluated for oocyte recovery and blastocyst production rate as dFBS (donors in favorable breeding season) or dNBS (donors in non-favorable breeding season). Embryos produced from dFBS or dNBS were cryopreserved by vitrification or the slow-freeze method for direct transfer and transferred to recipients in the favorable (rFBS) or non-favorable breeding season (rNBS). The heifers or cows were subjected to a fixed-time embryo transfer protocol and conception rates were determined on day 30 and on day 60. The oocyte recovery was lower in dFBS than in dNBS (7.6 vs. 10.0 oocyte/OPU, p = 0.0262); while no difference was found comparing blastocyst production rate (23.7% vs. 30.9% of blastocysts, respectively). Embryos from dFBS resulted in greater (p = 0.0013) conception rates on day 30 compared to dNBS (46.5% vs. 22.4%, respectively), despite the breeding season. The rFBS and rNBS treatments had similar (p = 0.6714) conception rates on day 30 (38.0% vs. 33.0%, respectively), indicating similar uterine receptivity. However, heifers on FBS had higher (p = 0.0003) conception rates on day 30 than cows (73.9% vs. 13.3%, respectively) when receiving embryos from dFBS. Vitrification and direct transfer had similar (p = 0.1698) conception rates on day 30 (30.4% vs. 41.4%, respectively). In conclusion, in vitro-produced embryos derived from dFBS were more competent in establishing pregnancy than dNBS counterparts, independent of recipients' reproductive seasonality. Heifers achieved better conception rates than cows during the favorable breeding season when the embryo came from dFBS. Cryopreserved in vitro produced embryos represent a reliable alternative to reduce seasonal variations in buffalo reproduction. The data elucidate the seasonal effects on embryo competence and on recipients' uterine receptivity, affording new strategies to implement ovum pick-up associated with in vitro embryo production programs in buffalo herds.


Assuntos
Búfalos , Recuperação de Oócitos , Animais , Bovinos , Transferência Embrionária/veterinária , Feminino , Fertilização in vitro/veterinária , Recuperação de Oócitos/veterinária , Gravidez , Reprodução
5.
Angew Chem Int Ed Engl ; 59(39): 17266-17271, 2020 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-32579755

RESUMO

Hydrodesulphurization, the removal of sulphur from crude oils, is an essential catalytic process in the petroleum industry safeguarding the production of clean hydrocarbons. Sulphur removal is critical for the functionality of downstream processes and vital to the elimination of environmental pollutants. The effectiveness of such an endeavour is among other factors determined by the structural arrangement of the heterogeneous catalyst. Namely, the accessibility of the catalytically active molybdenum disulphide (MoS2 ) slabs located on the surfaces of a porous alumina carrier. Here, we examined a series of pristine sulfided Mo and NiMo hydrodesulphurization catalysts of increasing metal loading prepared on commercial alumina carriers using ptychographic X-ray computed nanotomography. Structural analysis revealed a build consisting of two interwoven support matrix elements differing in nanoporosity. With increasing metal loading, approaching that of industrial catalysts, these matrix elements exhibit a progressively dissimilar MoS2 surface coverage as well as MoS2 cluster formation at the matrix element boundaries. This is suggestive of metal deposition limitations and/ or catalyst activation and following prohibitive of optimal catalytic utilization. These results will allow for diffusivity calculations, a better rationale of current generation catalyst performance as well as a better distribution of the active phase in next-generation hydrodesulphurization catalysts.

6.
J Anal Toxicol ; 44(5): 514-520, 2020 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-31984423

RESUMO

Smoking is a public health problem and an important source of exposure to toxic metals. This work describes an efficient analytical method comparable to the ones based on atomic emission techniques for the determination of chromium in different constituent parts of cigarette samples (tobacco, filters and ashes) using electrothermal vaporization-atomic absorption spectrometry. The method was evaluated using 12 samples, and the results showed recovery values between 83 and 107%. The accuracy was also evaluated using a reference sample of tomato leaves (NIST SRM 1573a), which proved the efficiency of the method. The limits of detection of the developed method were 20.4, 75.8 and 80.7 ng g-1 for tobacco, filter and cigarette ash samples, respectively. The average chromium values found for the analyzed samples were in the range of 0.96 to 3.85 and from 0.32 to 0.80 µg/cigarette for tobacco and ashes, respectively. For most pre-burn and post-burn filter samples, the values of chromium concentration remained below limits of detection. The developed method presented adequate results about precision and accuracy, demonstrating its applicability in the determination of chromium in cigarette samples.


Assuntos
Cromo/análise , Produtos do Tabaco/análise , Brasil , Humanos , Fumar , Nicotiana/química , Produtos do Tabaco/legislação & jurisprudência
7.
J Synchrotron Radiat ; 27(Pt 1): 185-198, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31868751

RESUMO

Friedreich's ataxia (FRDA) is a neurodegenerative disease characterized by an increase in intracytoplasmic iron concentration. Here the nanoscale iron distribution within single fibroblasts from FRDA patients was investigated using synchrotron-radiation-based nanoscopic X-ray fluorescence and X-ray in-line holography at the ID16A nano-imaging beamline of the ESRF. This unique probe was deployed to uncover the iron cellular two-dimensional architecture of freeze-dried FRDA fibroblasts. An unsurpassed absolute detection capability of 180 iron atoms within a 30 nm × 50 nm nanoscopic X-ray beam footprint was obtained using state-of-the-art X-ray focusing optics and a large-solid-angle detection system. Various micrometre-sized iron-rich organelles could be revealed for the first time, tentatively identified as endoplasmic reticulum, mitochondria and lysosomes. Also a multitude of nanoscopic iron hot-spots were observed in the cytosol, interpreted as chaperoned iron within the fibroblast's labile iron pool. These observations enable new hypotheses on the storage and trafficking of iron in the cell and ultimately to a better understanding of iron-storage diseases such as Friedreich's ataxia.


Assuntos
Fibroblastos/química , Ataxia de Friedreich/patologia , Holografia/métodos , Ferro/análise , Análise de Célula Única/métodos , Espectrometria por Raios X/métodos , Carbono , Citoplasma/química , Fibroblastos/ultraestrutura , Liofilização , Humanos , Nanoestruturas , Organelas/química , Organelas/ultraestrutura , Análise de Célula Única/instrumentação , Síncrotrons , Fixação de Tecidos/métodos
8.
J Synchrotron Radiat ; 26(Pt 6): 1887-1901, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31721731

RESUMO

Different approaches to simulate a modern X-ray beamline are considered. Several methodologies with increasing complexity are applied to discuss the relevant parameters that quantify the beamline performance. Parameters such as flux, dimensions and intensity distribution of the focused beam, and coherence properties are obtained from simple analytical calculations to sophisticated computer simulations using ray-tracing and wave optics techniques. A latest-generation X-ray nanofocusing beamline for coherent applications (ID16A at the ESRF) has been chosen to study in detail the issues related to highly demagnifying synchrotron sources and exploiting the beam coherence. The performance of the beamline is studied for two storage rings: the old ESRF-1 (emittance 4000 pm) and the new ESRF-EBS (emittance 150 pm). In addition to traditional results in terms of flux and beam sizes, an innovative study on the partial coherence properties based on the propagation of coherent modes is presented. The different algorithms and methodologies are implemented in the software suite OASYS. These are discussed with emphasis placed upon the their benefits and limitations of each.

9.
Physiol Behav ; 211: 112677, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499050

RESUMO

We investigated the acute effects of aerobic exercise with blood flow restriction (BFR) on mood state in American football athletes. Twenty-two male American football athletes were randomly assigned to three experimental conditions: 1) aerobic exercise (AE: 40% VO2max), 2) aerobic exercise with BRF (AE + BFR: 40% VO2 max), and 3) high-intensity interval exercise (HIIE: 80% and 40% VO2max during exercise and the active intervals, respectively). Mood state and total mood disturbance (TMD) were assessed before, immediately post, and 1 h post-exerciser. Ratings of perceived exertion (RPE) were measured 30 min post-exercise. AE + BFR and HIIE significantly (p < 0.05) increased fatigue and tension compared to baseline immediately post-exercise, whereas vigor significantly (p < 0.05) decreased at the same time point for both conditions. TMD increased significantly (p < 0.05) for AE + BFR and HIIE immediately post-exercise and it remained elevated up to 1 h post-exercise for AE + BFR. AE did not significantly (p > 0.05) affect mood state or TMD and it was significantly (p < 0.05) lower than AE + BFR and HIIE. AE + BFR and HIIE also elicited significantly (p < 0.05) greater RPE levels than AE 30 min post-exercise. Therefore, AE + BFR induces acute impairments in mood state and RPE levels in a similar fashion to HIIE.


Assuntos
Afeto/fisiologia , Atletas/psicologia , Exercício Físico/psicologia , Hemodinâmica/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Adulto , Exercício Físico/fisiologia , Futebol Americano , Treinamento Intervalado de Alta Intensidade , Humanos , Masculino , Músculo Esquelético/fisiologia , Consumo de Oxigênio/fisiologia , Esforço Físico , Resultado do Tratamento , Adulto Jovem
10.
J Synchrotron Radiat ; 26(Pt 5): 1751-1762, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31490167

RESUMO

X-ray ptychography is a coherent diffraction imaging technique with a high resolving power and excellent quantitative capabilities. Although very popular in synchrotron facilities nowadays, its implementation with X-ray energies above 15 keV is very rare due to the challenges imposed by the high energies. Here, the implementation of high-energy X-ray ptychography at 17 and 33.6 keV is demonstrated and solutions to overcome the important challenges are provided. Among the particular aspects addressed are the use of an efficient high-energy detector, a long synchrotron beamline for the high degree of spatial coherence, a beam with 1% monochromaticity providing high flux, and efficient multilayer coated Kirkpatrick-Baez X-ray optics to shape the beam. The constraints imposed by the large energy bandwidth are carefully analyzed, as well as the requirements to sample correctly the high-energy diffraction patterns with small speckle size. In this context, optimized scanning trajectories allow the total acquisition time to be reduced by up to 35%. The paper explores these innovative solutions at the ID16A nano-imaging beamline by ptychographic imaging of a 200 nm-thick gold lithography sample.


Assuntos
Óptica e Fotônica/instrumentação , Intensificação de Imagem Radiográfica/instrumentação , Síncrotrons , Desenho de Equipamento , Ouro/química , Modelos Teóricos , Difração de Raios X , Raios X
11.
Angew Chem Int Ed Engl ; 58(11): 3461-3465, 2019 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-30663197

RESUMO

A series of tamoxifen-like metallocifens of the group-8 metals (Fe, Ru, and Os) has strong antiproliferative activity on the triple-negative breast cancer cells (MDA-MB-231). To shed light on the mechanism of action of these molecules, synchrotron radiation X-ray fluorescence nanoimaging studies were performed on cells exposed to osmocenyl-tamoxifen (Oc-OH-Tam) to disclose its intracellular distribution. High-resolution mapping of the lipophilic Oc-OH-Tam in cells revealed its preferential accumulation in the endomembrane system. This is consistent with the ability of the amino nitrogen chain of the compounds to be protonated at physiological pH and responsible for electrostatic interactions between Oc-OH-Tam and membranes. A comprehensive scenario is proposed that provides new insight into the cellular behavior and activation of Oc-OH-Tam and advances the understanding of its mechanism of action.


Assuntos
Antineoplásicos/química , Complexos de Coordenação/química , Compostos Organometálicos/química , Tamoxifeno/química , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Antineoplásicos/metabolismo , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Complexos de Coordenação/metabolismo , Feminino , Humanos , Concentração de Íons de Hidrogênio , Ferro/química , Ligantes , Imagem Molecular/métodos , Sondas Moleculares/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Osmio/química , Radiografia , Rutênio/química , Eletricidade Estática , Síncrotrons , Raios X
13.
Arch Oral Biol ; 90: 45-52, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29533791

RESUMO

OBJECTIVE: This case-control study aimed to evaluate the effects of conventional radiotherapy (RT) on the prevalence and populations of oral microorganisms in head and neck cancer patients who did not receive adequate preventive dental care. It was hypothesized that side effects of radiotherapy could be associated with radiation dose, microbiological aspects, and socioeconomic conditions of the patients. DESIGN: Twenty-eight dentate patients with head and neck cancer submitted to RT were included in the study. Radiation dose received varied from 4320 to 7020 cGy. Patients with the same demographic and health conditions, but no history of cancer or antineoplastic treatment were used as controls. Clinical examinations were carried out before RT, 15-22 days after starting RT, immediately after and 6 months after RT. Supra and subgingival biofilms were collected and cultivated onto selective and non-selective media. Isolates were identified by biochemical and physiological characteristics. Stimulated and unstimulated salivary flow rate and saliva buffer capacity were also determined. RESULTS: Mucositis, dermatitis, xerostomia, dysgeusia, dysphagia and candidiasis were common after starting RT and during the treatment period. Xerostomia was followed by a decrease in salivary pH and buffer capacity, which showed association with the increase of cariogenic cocci and yeast populations, which were also associated with deterioration of hygiene. Candida and family Enterobacteriaceae showed increased prevalence with RT, and were associated with the occurrence of mucositis and xerostomia. CONCLUSIONS: Modifications in oral biofilms of irradiated patients showed association with xerostomia and hygiene conditions, which reinforces the necessity of improving patient compliance to oral health care programs.


Assuntos
Gengiva/microbiologia , Neoplasias de Cabeça e Pescoço/complicações , Neoplasias de Cabeça e Pescoço/microbiologia , Microbiota/efeitos da radiação , Radioterapia/efeitos adversos , Adolescente , Adulto , Idoso , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/efeitos da radiação , Biofilmes/efeitos da radiação , Brasil , Candida/isolamento & purificação , Candida/efeitos da radiação , Candidíase/etiologia , Estudos de Casos e Controles , Transtornos de Deglutição/etiologia , Dermatite/etiologia , Relação Dose-Resposta à Radiação , Disgeusia/etiologia , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/efeitos da radiação , Feminino , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Concentração de Íons de Hidrogênio , Masculino , Pessoa de Meia-Idade , Mucosite/etiologia , Higiene Bucal , Saliva/química , Uso de Tabaco/efeitos adversos , Xerostomia/etiologia , Adulto Jovem
14.
Materials (Basel) ; 10(3)2017 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-28772630

RESUMO

Selective laser melting is a promising powder-bed-based additive manufacturing technique for titanium alloys: near net-shaped metallic components can be produced with high resource-efficiency and cost savings [...].

15.
Theriogenology ; 90: 65-73, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28166990

RESUMO

We aimed with the present study to evaluate the effects of FSH treatment (200 mg) split in four or six administrations on ovarian follicle stimulation and in vitro oocyte competence for embryo production in dairy cows with synchronized follicular wave emergence. On random days of the estrous cycle (Day 0), non-lactating Holstein cows received a progesterone (P4)-releasing intravaginal device and 2 mg estradiol benzoate IM. On Day 3, they received 0.530 mg sodium cloprostenol (PGF2α) IM. Control cows (n = 35) received no further treatments, whereas FSH-treated cows received 200 mg FSH split in four (FSH4 group; n = 33) or six (FSH6 group; n = 33) administration regimens. Starting on Day 4, cows in FSH4 group received 200 mg FSH split in four equivalent doses of 50 mg 12 h apart. Cows in FSH6 group received the same total FSH dose split in six equivalent doses of 33.3 mg 12 h apart, but treatments started on Day 3. On Day 7 AM (36 h of "coasting" period for FSH-treated groups), the P4 devices were removed and cows were subjected to ovum pick up (OPU). Viable oocytes were in vitro fertilized using sexed-sorted semen. Although FSH treatment did not (P > 0.1) increase the total number of follicles (Control, 53.2 ± 4.5 vs. FSH-treated, 51.4 ± 3.1), the two hormonal stimulation regimens, FSH4 and FSH6, increased the number of medium follicles (6-10 mm; 5.2 ± 0.5 vs. 18.1 ± 1.4; P < 0.0001) and reduced the number of small follicles (2-5.9 mm; 46.3 ± 5.1 vs. 31.0 ± 2.4 P < 0.0001). Also, FSH treatment or regimen did not increase (P > 0.1) the number of viable oocytes (Control, 12.6 ± 1.26 vs. FSH-treated, 12.70 ± 1.03), recovery rate (Control, 36.5% vs. FSH-treated, 36%) and the number of in vitro produced blastocyst (Control, 4.1 ± 0.52 vs. FSH-treated 4.3 ± 0.5). We concluded that FSH stimulation protocol proposed herein is effective to stimulate the growth of small antral follicle population prior to OPU, but it was ineffective to improve in vitro oocyte competence for embryo production in non-lactating Holstein cows with synchronized follicular wave emergence.


Assuntos
Fertilização in vitro/veterinária , Hormônio Foliculoestimulante/farmacologia , Recuperação de Oócitos/veterinária , Indução da Ovulação/veterinária , Animais , Bovinos , Relação Dose-Resposta a Droga , Feminino , Fertilização in vitro/métodos , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/fisiologia
16.
Oral Maxillofac Surg ; 20(2): 123-33, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26572899

RESUMO

This double-blind, split-mouth, and randomized study was aimed to compare the efficacy of dexamethasone and ketorolac tromethamine, through the evaluation of pain, edema, and limitation of mouth opening. Thirty-four individuals aged 18-26 years, having bilateral mandibular third molars, in a similar position, were selected. Two different surgical procedures were performed on the same individual by the single surgeon. For an extraction, the individual received 1 capsule of 10 mg ketorolac tromethamine 1 h before surgery and every 8 h for 2 days. For the extraction of the contralateral side, the individual received 1 capsule of 8 mg dexamethasone 1 h before surgery and 1 placebo capsule every 8 h for 2 days. Sodium metamizol, 500 mg, was given as rescue medication in postoperative. Pain was assessed by the Visual Box Scale-11 points (BS-11) at 24 h postoperative. Edema (metric measurement) and the maximum mouth opening (interincisal) were recorded in the pre-operative, 24 h, 48 h, 72 h and 7 days postoperatively. The results showed that both therapeutic treatments used were effective in the postoperative, and there were no statistically significant differences between the groups for the pain and edema variables. However, for the limitation of mouth opening, 24 h and 7 days postoperatively, the dexamethasone group had a lower limitation of mouth opening, behaving better than the ketorolac for this variable in these periods. Due also to the higher margin of safety, the use of dexamethasone as a single dose becomes a more suitable alternative for use in routine surgical extractions of third molars.


Assuntos
Anti-Inflamatórios/uso terapêutico , Dexametasona/uso terapêutico , Cetorolaco de Trometamina/uso terapêutico , Dente Serotino/cirurgia , Extração Dentária , Adolescente , Adulto , Dipirona/uso terapêutico , Método Duplo-Cego , Esquema de Medicação , Edema/etiologia , Feminino , Humanos , Masculino , Pré-Medicação , Resultado do Tratamento , Trismo/etiologia , Escala Visual Analógica , Adulto Jovem
17.
J Chromatogr A ; 1388: 102-9, 2015 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-25721909

RESUMO

Bile acids (BAs) are derived from cholesterol and produced in the liver. The most abundant bile acids in humans are usually conjugated with glycine and taurine and are divided into primary BAs such as cholic acid (CA) and chenodeoxycholic acid (CDCA) and secondary BAs like deoxycholic acid (DCA), lithocholic acid (LCA) and ursodeoxycholic acid (UDCA). The differences amongst individual bile acids (BAs) are significant in order to distinguish different pathological processes and exposure to chemical compounds. Hollow fiber based liquid-phase microextraction (HF-LPME) is a technique that combines sample cleansing, extraction and the concentration of analytes, where a hydrophobic porous capillary membrane is impregnated with an organic extraction solvent and the lumen is filled with microliters of a phase acceptor both organic by nature. The aim of this study was to develop a new method to extract bile acids from plasma through HF-LPME of two phases (octanol as the acceptor phase) using LCMS-IT-TOF. The optimized two-phased LPME procedure for the extraction of bile acids showed limits of detection 1.0 µg L(-1) and limits of quantification of 5.0 µg L(-1). The intra-assay precision ranged from 2.1 to 11.9%. The method developed was linear over the range of 5.0-200.0 µg L(-1) for all analytes. The hollow-fiber liquid-phase microextraction method was applied to human plasma from workers exposed to organic and halogenated solvents and also to unexposed volunteers. The method is simple, low cost and it does not require large amounts of organic solvents, therefore it is quite suitable for the analysis of bile acids exposed to hepatotoxic compounds.


Assuntos
Ácidos e Sais Biliares/sangue , Cromatografia Líquida/métodos , Microextração em Fase Líquida/métodos , Exposição Ocupacional/análise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Adulto , Estudos de Casos e Controles , Humanos , Pessoa de Meia-Idade
18.
PLoS One ; 10(2): e0118574, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25710523

RESUMO

Achyrocline alata, known as Jateí-ka-há, is traditionally used to treat several health problems, including inflammations and infections. This study aimed to optimize an active extract against Streptococcus mutans, the main bacteria that causes caries. The extract was developed using an accelerated solvent extraction and chemometric calculations. Factorial design and response surface methodologies were used to determine the most important variables, such as active compound selectivity. The standardized extraction recovered 99% of the four main compounds, gnaphaliin, helipyrone, obtusifolin and lepidissipyrone, which represent 44% of the extract. The optimized extract of A. alata has a MIC of 62.5 µg/mL against S. mutans and could be used in mouth care products.


Assuntos
Achyrocline/química , Anti-Infecciosos/química , Extratos Vegetais/química , Achyrocline/metabolismo , Animais , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Linhagem Celular , Cromatografia Líquida de Alta Pressão , Hexanos/química , Peróxido de Hidrogênio/metabolismo , Extração Líquido-Líquido , Camundongos , Testes de Sensibilidade Microbiana , Óxido Nítrico/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Caules de Planta/química , Caules de Planta/metabolismo , Projetos de Pesquisa , Streptococcus mutans/efeitos dos fármacos
19.
J Chromatogr A ; 1379: 83-91, 2015 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-25577647

RESUMO

This work involved the optimization and validation of two methods according to the Commission Decision 2002/657/EC directives for determining fluoroquinolones residues in samples of poultry muscle and kidney: ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, flumequine, marbofloxacin, nalidixic acid, norfloxacin, ofloxacin, oxolinic acid, pipemidic acid and sarafloxacin. The extraction procedure was based on a QuEChERS approach, whose optimization employed a Box-Behnken 3(3) factorial design. A liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed for determining the twelve analytes using the multiple reaction monitoring mode (MRM). Accuracy, evaluated by recovery studies, varied from 88.8 to 112.2% for the selected levels with RSD values lower than 12.3%. The second validated method employed high resolution mass spectrometry (HRMS) performed in the single ion monitoring mode (SIM), determining nine among twelve analytes. The validation parameters were evaluated as satisfactory, with recoveries from 82.5 to 114.4% and RSD lower than 8.7%. Decision limits and detection capabilities for both methods were reported. The two methods were statistically compared using the Student's t test, at 95% confidence level, resulting in no significant difference.


Assuntos
Cromatografia Líquida , Fluoroquinolonas/análise , Tecnologia de Alimentos/métodos , Rim/química , Músculos/química , Espectrometria de Massas em Tandem , Animais , Antibacterianos/análise , Carne/análise , Aves Domésticas
20.
Opt Express ; 23(26): 33812-21, 2015 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-26832042

RESUMO

Ptychographic imaging has gained popularity for its high resolving power and sensitivity as well as for its ability to map simultaneously the sample's complex-valued refractive index and the illumination. Yet, despite significant progress that allows for reliable practical implementation, some of the technique's fundamentals remain poorly understood, and oftentimes successful data acquisition is either overly conservative or relies more on experimenters experience than on rational data acquisition strategies. Here, we propose a theoretical framework of ptychography, which is based on Gabor's notion of decomposition into elementary signals and the concept of frames. We demonstrate how this framework can straightforwardly be used to derive sampling requirements or to provide arguments on how to optimize the ptychographic scan. More generally, our theoretical framework can serve as a bridge between the experimental technique and the rich and well established mathematical disciplines of wavelets decomposition and spectrogram analysis.

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