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1.
J Food Sci ; 89(5): 2943-2955, 2024 May.
Article in English | MEDLINE | ID: mdl-38557930

ABSTRACT

Bell pepper presents rapid weight loss and is highly susceptible to gray mold caused by the fungus Botrytis cinerea. The most employed method to control this disease is the application of synthetic fungicides such as thiabendazole (TBZ); however, its continued use causes resistance in fungi as well as environmental problems. For these reasons, natural alternatives arise as a more striking option. Currently, bell pepper fruits are coated with carnauba wax (CW) to prevent weight loss and improve appearance. Moreover, CW can be used as a carrier to incorporate essential oils, and previous studies have shown that thyme essential oil (TEO) is highly effective against B. cinerea. Therefore, this study aimed to evaluate the effect of CW combined with TEO on the development of gray mold and maintenance of microestructural and postharvest quality in bell pepper stored at 13°C. The minimal inhibitory concentration of TEO was 0.5%. TEO and TBZ provoked the leakage of intracellular components. TEO and CW + TEO treatments were equally effective to inhibit the development of gray mold. On the quality parameters, firmness and weight loss were ameliorated with CW and CW + TEO treatments; whereas lightness increased in these treatments. The structural analysis showed that CW + TEO treatment maintained the cell structure reducing the apparition of deformities. The results suggest that CW + TEO treatment could be used as a natural and effective antifungal retarding the appearance of gray mold and maintaining the postharvest quality of bell pepper. PRACTICAL APPLICATION: CW and TEO are classified as generally recognized as safe (GRAS) by the US Food and Drug Administration (FDA). This combination can be employed on the bell pepper packaging system to extend shelf life and oppose gray mold developments. Bell pepper fruits are normally coated with lipid-base coatings such as CW before commercialization; therefore, TEO addition would represent a small investment without any changes on the packaging system infrastructure.


Subject(s)
Botrytis , Capsicum , Food Preservation , Fruit , Oils, Volatile , Thymus Plant , Waxes , Botrytis/drug effects , Capsicum/microbiology , Capsicum/chemistry , Thymus Plant/chemistry , Oils, Volatile/pharmacology , Waxes/chemistry , Waxes/pharmacology , Food Preservation/methods , Fruit/microbiology , Fruit/chemistry , Plant Diseases/microbiology , Plant Diseases/prevention & control , Fungicides, Industrial/pharmacology
2.
Methods Appl Fluoresc ; 12(1)2023 Oct 12.
Article in English | MEDLINE | ID: mdl-37751748

ABSTRACT

Fluorescence microscopy can provide valuable information about cell interior dynamics. Particularly, mean squared displacement (MSD) analysis is widely used to characterize proteins and sub-cellular structures' mobility providing the laws of molecular diffusion. The MSD curve is traditionally extracted from individual trajectories recorded by single-particle tracking-based techniques. More recently, image correlation methods like iMSD have been shown capable of providing averaged dynamic information directly from images, without the need for isolation and localization of individual particles. iMSD is a powerful technique that has been successfully applied to many different biological problems, over a wide spatial and temporal scales. The aim of this work is to review and compare these two well-established methodologies and their performance in different situations, to give an insight on how to make the most out of their unique characteristics. We show the analysis of the same datasets by the two methods. Regardless of the experimental differences in the input data for MSD or iMSD analysis, our results show that the two approaches can address equivalent questions for free diffusing systems. We focused on studying a range of diffusion coefficients between D = 0.001µm2s-1and D = 0.1µm2s-1, where we verified that the equivalence is maintained even for the case of isolated particles. This opens new opportunities for studying intracellular dynamics using equipment commonly available in any biophysical laboratory.

3.
Front Vet Sci ; 9: 998438, 2022.
Article in English | MEDLINE | ID: mdl-36439358

ABSTRACT

Red blood cells (RBC) morphologic evaluation through microscopy optical (OM) and SEM, provides information to forecast, evaluate, and monitor the functioning of many organs. Factors, such aging and diseases affect RBC morphology in both, human and animals. SEM is useful to evaluate RBC morphology, although its use in diagnosis and evaluation in dogs is limited, due to the availability and cost. The aim of this research was to assess the normal RBC morphology in adult, senior and geriatrician dogs, clinically healthy by OM and SEM. In addition to evaluating the age effect, sex, body size, and their interaction on erythrocyte morphometry. To carry out the research 152 blood samples were evaluated from dogs of different sexes and body sizes (small, medium, and large). Three groups were made based on dogs age: group I adults (1-7.9 years old), group II senior (8-11.9 years old), and group III geriatricians (>12 years old). Erythrocyte parameters were evaluated by OM (diameter, height, and axial ratio). Per each dog, the parameters of 20 erythrocytes were measured. A total of 2,600 cells were scanned with the AmScope™ Software scale. In addition, the RBC morphology was evaluated by SEM. Statistical analyses used analysis of variance and a general linear model, which allows the comparison of multiple factors at two or more levels (p < 0.05). The results of this study showed that diameter and height were lower in adult dogs than in senior and geriatrician dogs (p < 0.05). Whereas, sex, body size, and the interaction did not show a significant effect (p > 0.05). Additionally, some images of anisocytosis, polychromasia, and poikilocytosis (echinocytes, acanthocytes, codocytes, spherocytes, stomatocytes, dacryocytes quatrefoil, and elliptocytes) were obtained by OM and SEM. Our study provides information about the morphological and morphometry alterations of adult, senior, and geriatrician dogs RBC. This work contributes to future investigations and the diagnosing diseases, where it is necessary to evaluate the morphology of RBC.

4.
J Fluoresc ; 31(5): 1417-1424, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34241793

ABSTRACT

Two reactive phenanthrene derivatives, 4-(1H phenanthrol [9,10-d] imidazole-2-yl) benzaldehyde (PIB) and 6,9-dimethoxyphenanthro[9,10-c]furan-1,3-dione (PA) with high fluorescent quantum yields were prepared and used as fluorescent marker in fluorescence microscopy. In particular, silane modified µmZeolite-L containing amino group (-NH2) in the surface were labeled with the phenanthrene derivatives allowing good imaging resolution and spectroscopy measurements. The presence of a large Stokes shift of the probes due to their intramolecular charge-transfer character gives an advantage of the compounds in confocal laser fluorescence microscopy due to easy signal separation in excitation and emission wavelengths. On the other hand, these results open up the possibility of using these probes for visualization of Zeolite-based materials commonly used as catalysts in thermal and photochemical reactions.

5.
Rev. ciênc. farm. básica apl ; Rev. ciênc. farm. básica apl;42: 1-11, 20210101.
Article in English | LILACS-Express | LILACS | ID: biblio-1280856

ABSTRACT

Objective: In this study, we aimed to determine the action of the tinctures of Hamamelis virginiana, Maytenus ilicifolia, and Casearia sylvestris on tissues. For this, we investigated the histological sections of fixed skin tissue of Wistar rats for the changes in collagen and elastic fibers, epithelial cells, conjunctive cells, epidermal attachments, pigments, and granules using the optical microscopy technique. Since in the literature and published articles, the use of in vivo models, such as Wistar rats, is predominant to evaluate the healing action of herbal medicines. Methods: The tinctures of Hamamelis virginiana, Maytenus ilicifolia, and Casearia sylvestris, and ethanol 70% (blank) were used. The tinctures were obtained at 10% (w/v) through percolation using 70% ethanol (v/v) as the extraction liquid. This study was conducted in duplicate for each tincture and different incubation times (4, 24, and 48 h) at 37 °C in an oven. The slides used in this study (Wistar rat skin) were previously processed at the histology laboratory since the waste material was donated to conduct this experiment. The Research Ethics Committee approved the use of animals of the Life Sciences Center of the Pontifical Catholic University of Campinas (PUC-CAMPINAS) under the protocol approval number 367/08. Before initiating the staining process, the slides were removed from the oven, and the tincture deposited on the slides was removed. Weigert staining was performed subsequently. For semi-quantitative analysis, the histological sections were carefully observed, and the number of collagen and elastic fibers was evaluated based on the following scale: (+) normal fiber presence, (−) slight decrease, (− −) moderate decrease, and (− − −) intense decrease. The images were digitally captured to obtain the results using a photomicroscope. Results: The degradation of collagen fibers was best evidenced upon using Hamamelis virginiana tincture, which is concordant with the existing reports in the literature on its healing action via the precipitation of dermal proteins. Maytenus ilicifolia and Casearia sylvestris tinctures exhibited low proteolytic capacity as they only caused degradation of elastic fibers that are more delicate and very different from collagen in their constitution. Therefore, the application of the latter two as healing agents (which acts through precipitating proteins) is limited. Conclusions: This experimental histological model using the optical microscopy technique exhibits the advantage of agility and high efficiency as a simple and powerful approach.

6.
Theriogenology ; 159: 60-68, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33113445

ABSTRACT

The assessment of embryo quality aims to enhance subsequent pregnancy and live birth outcomes. Metabolic analysis of embryos has immense potential in this regard. As a step towards this goal, here we assess the metabolism of bovine embryos using label-free optical imaging. We compared embryos defined as either on-time or fast-developing, as fast dividing embryos are more likely to develop to the blastocyst stage. Specifically, bovine embryos at 48 (Day 2) and 96 (Day 4) hours post fertilization were fixed and separated based on morphological assessment: on-time (Day 2: 2 cell; Day 4: 5-7 cell) or fast-developing (Day 2: 3-7 cell; Day 4: 8-16 cell). Embryos with different developmental rates on Day 2 and Day 4 were correlated with metabolic activity and DNA damage. Confocal microscopy was used to assess metabolic activity by quantification of cellular autofluorescence specific for the endogenous fluorophores NAD(P)H and FAD with a subsequent calculation of the optical redox ratio. Separately, hyperspectral microscopy was employed to assess a broader range of endogenous fluorophores. DNA damage was determined using γH2AX immunohistochemistry. Hyperspectral imaging showed significantly lower abundance of endogenous fluorophores in fast-developing compared to on-time embryos on Day 2, indicating a lower metabolic activity. On Day 4 of development there was no difference in the abundance of FAD between on-time and fast-developing embryos. There was, however, significantly higher levels of NAD(P)H in fast-developing embryos leading to a significantly lower optical redox ratio when compared to on-time embryos. Collectively, these results demonstrate that fast-developing embryos present a 'quiet' metabolic pattern on Day 2 and Day 4 of development, compared to on-time embryos. There was no difference in the level of DNA damage between on-time and fast-developing embryos on either day of development. To our knowledge, this is the first collective use of confocal and hyperspectral imaging in cleavage-stage bovine embryos in the absence of fluorescent tags.


Subject(s)
Blastocyst , Embryo Transfer , Animals , Cattle , Embryo Transfer/veterinary , Embryo, Mammalian , Embryonic Development , Female , Fertilization in Vitro/veterinary , Microscopy/veterinary , Optical Imaging/veterinary , Pregnancy
7.
Front Bioeng Biotechnol ; 8: 597950, 2020.
Article in English | MEDLINE | ID: mdl-33262979

ABSTRACT

Cells interact with their microenvironment by constantly sensing mechanical and chemical cues converting them into biochemical signals. These processes allow cells to respond and adapt to changes in their environment, and are crucial for most cellular functions. Understanding the mechanism underlying this complex interplay at the cell-matrix interface is of fundamental value to decipher key biochemical and mechanical factors regulating cell fate. The combination of material science and surface chemistry aided in the creation of controllable environments to study cell mechanosensing and mechanotransduction. Biologically inspired materials tailored with specific bioactive molecules, desired physical properties and tunable topography have emerged as suitable tools to study cell behavior. Among these materials, synthetic cell interfaces with built-in sensing capabilities are highly advantageous to measure biophysical and biochemical interaction between cells and their environment. In this review, we discuss the design of micro and nanostructured biomaterials engineered not only to mimic the structure, properties, and function of the cellular microenvironment, but also to obtain quantitative information on how cells sense and probe specific adhesive cues from the extracellular domain. This type of responsive biointerfaces provides a readout of mechanics, biochemistry, and electrical activity in real time allowing observation of cellular processes with molecular specificity. Specifically designed sensors based on advanced optical and electrochemical readout are discussed. We further provide an insight into the emerging role of multifunctional micro and nanosensors to control and monitor cell functions by means of material design.

8.
Front Neurosci ; 14: 555, 2020.
Article in English | MEDLINE | ID: mdl-32581692

ABSTRACT

Tubulinopathies are a group of recently described diseases characterized by mutations in the tubulin genes. Mutations in TUBB4A produce diseases such as dystonia type 4 (DYT4) and hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC), which are clinically diagnosed by magnetic resonance imaging (MRI). We propose the taiep rat as the first animal model for tubulinopathies. The spontaneous mutant suffers from a syndrome related to a central leukodystrophy and characterized by tremor, ataxia, immobility, epilepsy, and paralysis. The pathological signs presented by these rats and the morphological changes we found by our longitudinal MRI study are similar to those of patients with mutations in TUBB4A. The diffuse atrophy we found in brain, cerebellum and spinal cord is related to the changes detectable in many human tubulinopathies and in particular in H-ABC patients, where myelin degeneration at the level of putamen and cerebellum is a clinical trademark of the disease. We performed Tubb4a exon analysis to corroborate the genetic defect and formulated hypotheses about the effect of amino acid 302 change on protein physiology. Optical microscopy of taiep rat cerebella and spinal cord confirmed the optical density loss in white matter associated with myelin loss, despite the persistence of neural fibers.

9.
J Microsc ; 277(2): 93-99, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31997353

ABSTRACT

Following the first and second generations, the challenge in obtaining a better balance between strength and elongation is still the main characteristic of the third generation of advanced high-strength steels (AHSS). With this, the use of multiphase microstructures has increased over the last few years. It can be difficult to characterize all the phases with only optical microscopy (OM), so the use of scanning electron microscopy (SEM) is essential for accuracy in cases where researchers lack experience. To expand the possibilities, this research proposed a new approach that would allow experienced researchers to characterize multiphase steels using only OM. A high silicon steel was austempered slightly below martensite start (Ms) temperature for three different time periods in order to obtain different quantities of martensite, bainite and retained austenite. X-ray diffraction was carried out in order to confirm and obtain retained austenite volume fractions, and the results indicated that shorter holding times were not enough to enrich and stabilize retained austenite. Then, each samples was etched with four different etchants. Results showed that the new multiple etchings methodology (MEM) allowed a better visualization of all the phases when viewed together. Beraha martensitc revealed nontempered martensitic microstructures. Sodium metabisulfite revealed retained austenite. LePera and Nital were the best at revealing the evolution of the microstructure over time, even with the changes which occurred due to martensite tempering. SEM images confirmed the results obtained via MEM. LAY DESCRIPTION: For improving safety, environmental protection, mechanical resistance and others issues, many different steel grades have been studied. These grades were named depending on their mechanical properties. The current generation is the third, which is still searching for one of the main antagonists in material science: the best balance between mechanical resistance (how strong it is) and elongation (how long it can be stretched to). In order to achieve this goal, many researchers are studying variations in the production processes. During production, the materials are able to internally change their basic microstructure, named phases. In the past, steels were usually produced to have only a few phases. Today's advanced high strength steels (AHSS) can have many. Each of these phases has its own characteristics. The main focus of this research was to give a new way of identify these phases using an optical microscope. For revealing these phases, etchants are normally used. The etchants used in this research are capable of tinting each of these phases with a different colour or tone. So the purpose of this work was to suggest a new approach in order to allow for more precise identification of the phases in the steel. The results were positive, showing that looking at the samples as a whole is better than the traditional methods. Also, different etchants' characteristics were observed during the changes obtained by this work's chosen processes.

10.
J Mol Biol ; 432(3): 682-693, 2020 02 07.
Article in English | MEDLINE | ID: mdl-31904354

ABSTRACT

Eukaryotic genomes are folded in a hierarchical organization that reflects and possibly regulates their function. Genomewide studies revealed a new level of organization at the kilobase-to-megabase scale termed "topological associating domains" (TADs). TADs are characterized as stable units of chromosome organization that restrict the action of regulatory sequences within one "functional unit." Consequently, TADs are expected to appear as physical entities in most cells. Very recent single-cell studies have shown a notable variability in genome architecture at this scale, raising concerns about this model. Furthermore, the direct and simultaneous observation of genome architecture and transcriptional output showed the lack of stable interactions between regulatory sequences in transcribing cells. These findings are consistent with a large body of evidence suggesting that genome organization is highly heterogeneous at different scales. In this review, we discuss the main strategies employed to image chromatin organization, present the latest state-of-the-art developments, and propose an interpretation reconciling population-based findings with direct single-cell chromatin organization observations. All in all, we propose that TADs are made of multiple, low-frequency, low-affinity interactions that increase the probability, but are not deterministic, of regulatory interactions.


Subject(s)
Chromatin/chemistry , Chromatin/metabolism , Macromolecular Substances/chemistry , Macromolecular Substances/metabolism , Molecular Conformation , Single Molecule Imaging , Eukaryota , Microscopy
11.
Environ Sci Pollut Res Int ; 27(7): 7409-7419, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31884541

ABSTRACT

Many reports state the potential hazards of microplastics (MPs) and their implications to wildlife and human health. The presence of MP in the aquatic environment is related to several origins but particularly associated to their occurrence in wastewater effluents. The determination of MP in these complex samples is a challenge. Current analytical procedures for MP monitoring are based on separation and counting by visual observation or mediated with some type of microscopy with further identification by techniques such as Raman or Fourier-transform infrared (FTIR) spectroscopy. In this work, a simple alternative for the separation, counting and identification of MP in wastewater samples is reported. The presented sample preparation technique with further polarized light optical microscopy (PLOM) observation positively identified the vast majority of MP particles occurring in wastewater samples of Montevideo, Uruguay, in the 70-600 µm range. MPs with different shapes and chemical composition were identified by PLOM and confirmed by confocal Raman microscopy. Rapid identification of polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) were evidenced. A major limitation was found in the identification of MP from non-birefringent polymers such as PVC (polyvinylchloride). The proposed procedure for MP analysis in wastewater is easy to be implemented at any analytical laboratory. A pilot monitoring of Montevideo WWTP effluents was carried out over 3-month period identifying MP from different chemical identities in the range 5.3-8.2 × 103 MP items/m3.


Subject(s)
Microplastics/analysis , Wastewater , Water Pollutants, Chemical , Environmental Monitoring , Microplastics/chemistry , Microscopy , Wastewater/analysis , Wastewater/chemistry
12.
Microsc Res Tech ; 81(2): 191-197, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29083081

ABSTRACT

The aim of this study was to evaluate the effect of 24% ethylenediaminetetraacetic acid (EDTA) gel and 2% chlorhexidine gel (CHX) in dentin permeability and smear layer removal from root canals instrumented with NiTi rotary system using histochemical staining and scanning electron microscopy (SEM) analysis. Overall, 43 premolars were classified into two experimental groups, EDTA (n = 20) and CHX (n = 20), and a negative control (NC) (n = 3). All specimens were instrumented and the irrigant solutions were used after each file change. The EDTA group received a final rinse with 5-ml 1% NaOCl followed by a 5-ml 0.9% saline solution; the CHX group received a final rinse with 10-ml 0.9% saline solution; and the negative control group received a final rinse with only 0.9% saline solution. Fifteen teeth from each group were prepared for histochemical staining and evaluation of dentin permeability using the image-scanning software Axion Vision (v.4.8.2). Five remaining teeth were prepared for analysis using SEM for morphological analysis. The study found that 24% EDTA gel increased the permeability of dentin in all thirds evaluated and also demonstrated an increased cleaning ability, with dentinal walls free of smear layer and open dentinal tubules, as compared to 2% CHX gel. It was concluded that EDTA was efficient in cleaning the dentinal tubules and increased dentin permeability.


Subject(s)
Chlorhexidine/pharmacology , Dentin Permeability/drug effects , Dentin/drug effects , Edetic Acid/pharmacology , Dental Pulp Cavity/drug effects , Gels/pharmacology , Humans , Microscopy/methods , Microscopy, Electron, Scanning/methods , Root Canal Irrigants/pharmacology , Root Canal Preparation
13.
Biomed Rep ; 7(3): 247-250, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28894572

ABSTRACT

Virtual microscopy is currently widely used for various purposes, such as teaching, archiving, collaborations and research. Although the cost of this technique has reduced, it continues to be expensive for the majority of laboratories in developing countries. The Graduate Program in Pathology at the Federal Fluminense University (Niterói, Brazil) has acquired equipment for virtual microscopy. However, this novel method faced prejudice, as students and technicians were skeptical about its reliability. Thus, the aim of the current study was to evaluate whether virtual microscopy is a reliable method of analysis for our research. Thus, a mouse gut inflammation model developed by our research group was used in the present study. Analysis was performed using optical microscopy and digital imaging using the APERIO scanning system and the ImageScope® software. Intestinal epithelial cells (IECs), intra epithelial leucocytes (IEL), and villi number and area were evaluated. No significant differences were observed in villi number, IEC and IEL; however, the villi area was significantly smaller when measured using the computer. Thus, the present study indicates that virtual microscopy is a trustworthy method for research purposes.

14.
Nano Lett ; 17(5): 2741-2746, 2017 05 10.
Article in English | MEDLINE | ID: mdl-28414911

ABSTRACT

Analysis of nanoscale liquids, including wetting and flow phenomena, is a scientific challenge with far reaching implications for industrial technologies. We report the conception, development, and application of an integrated platform for the experimental characterization of liquids at the nanometer scale. The platform combines the functionalities of a two-dimensional electronic array of sensor devices with in situ application of highly sensitive optical microspectroscopy and atomic force microscopy. We demonstrate the performance capabilities of the platform with an embodiment based on an array of optically transparent graphene sensors. The application of electronic and optical sensing in the platform allows for differentiating between liquids electronically, for determining a liquid's molecular fingerprint, and for monitoring surface wetting dynamics in real time. In order to explore the platform's sensitivity limits, we record topographies and optical spectra of individual, spatially isolated sessile oil emulsion droplets having volumes of less than ten attoliters. The results demonstrate that integrated measurement functionalities based on two-dimensional materials have the potential to push lab-on-chip based analysis from the microscale to the nanoscale.

15.
Braz. j. pharm. sci ; 52(2): 273-280, Apr.-June 2016. tab, graf
Article in English | LILACS | ID: lil-795004

ABSTRACT

ABSTRACT The physicochemical attributes of emulsified systems are influenced by the characteristics of their internal phase droplets (concentration, size and morphology), which can be modified not only by the formulation components, but also by the analytical methodology employed. Thus, the aim of this work involved the physicochemical characterization of cosmetic emulsions obtained from different surfactants, as well as the introduction of the optical coherence tomography (OCT) as the analytical technique employed for the morphological characterization and particle size determination of the formulations. Three emulsions were prepared, differing at the type and concentration of the surfactant used, and their droplet sizes were evaluated through optical microscopy, laser diffraction and OCT. The microscopic analysis and the laser diffraction techniques provided an average particle size minor than 6.0 µm, not detected by the OCT technique, which could identify only bigger particles of the emulsified systems' internal phase. The results testify that OCT was suitable for the morphological characterization of cosmetic emulsions; however, the technique needs to be improved to ensure a better sensitivity in the analysis of smaller particles.


RESUMO Os atributos físico-químicos de sistemas emulsionados são influenciados pelas características de suas gotículas de fase interna (concentração, tamanho e morfologia), as quais podem ser modificadas não apenas pelos componentes da formulação, mas também pela metodologia analítica empregada. Desta forma, o objetivo deste trabalho envolveu a caracterização físico-química de emulsões cosméticas obtidas a partir de diferentes tensoativos, bem como a introdução da tomografia de coerência óptica (OCT) como a técnica analítica utilizada para a caracterização morfológica e determinação do tamanho de partícula das formulações. Três emulsões foram preparadas, diferindo no tipo e concentração do tensoativo empregado, e seus tamanhos de gotícula foram avaliados por meio das técnicas de microscopia óptica, difração a laser e OCT. As técnicas de microscopia óptica e difração a laser forneceram tamanhos de partícula médios menores de 6.0 µm, não detectados pela técnica de OCT, que permitiu apenas a identificação de partículas maiores pertencentes à fase interna dos sistemas emulsionados. Os resultados reforçam a introdução da OCT como metodologia promissora para a caracterização morfológica de emulsões cosméticas; no entanto, a técnica requer aprimoramento para garantir maior sensibilidade na análise de partículas de menor tamanho.


Subject(s)
Tomography, Optical Coherence/methods , Emulsions/analysis , Surface-Active Agents/analysis
16.
J Microsc ; 257(1): 54-64, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25231792

ABSTRACT

Field-enhanced scanning optical microscopy relies on the design and fabrication of plasmonic probes which had to provide optical and chemical contrast at the nanoscale. In order to do so, the scattering containing the near-field information recorded in a field-enhanced scanning optical microscopy experiment, has to surpass the background light, always present due to multiple interferences between the macroscopic probe and sample. In this work, we show that when the probe-sample distance is modulated with very low amplitude, the higher the harmonic demodulation is, the better the ratio between the near-field signal and the interferometric background results. The choice of working at a given n harmonic is dictated by the experiment when the signal at the n + 1 harmonic goes below the experimental noise. We demonstrate that the optical contrast comes from the nth derivative of the near-field scattering, amplified by the interferometric background. By modelling the far and near field we calculate the probe-sample approach curves, which fit very well the experimental ones. After taking a great amount of experimental data for different probes and samples, we conclude with a table of the minimum enhancement factors needed to have optical contrast with field-enhanced scanning optical microscopy.

17.
Rev. ing. bioméd ; 8(16): 13-18, jul.-dic. 2014. graf
Article in English | LILACS | ID: lil-769153

ABSTRACT

Diathermy pencils are one of the most employed medical devices around the world, this condition increases its probability to be reprocessing in patients; diathermy pencil has different parts (cord, tip, handgrip, current cables), which are composed of different kind of materials. In order to identify the medical device behavior is necessary to characterize all of those materials in the instrument. An exploration to determinate topographic surface defects and structural movements in each material was performed, with the intention of evaluated the reuse cycles effects on the medical device. The experiment was performing using the EIA/CES "QUALY" approach [1]. The study concludes that four reprocessing cycles induce some changes that are not statistically representative. Surface defects were detected in the cord; also an aggressive superficial waste after four reprocessing cycles in the tip was observed. We do not observe structural changes in the polymeric chain of the cord.


Los lápices diatermia son uno de los dispositivos médicos más empleados en todo el mundo, condición que aumenta su probabilidad de ser reprocesados con pacientes. El lápiz diatermia tiene diferentes partes (cable, punta, empuñadura, cables de corriente), que están compuestas de diferentes tipos de materiales. Con el fin de identificar el comportamiento de dispositivos médicos es necesario caracterizar todos esos materiales en el instrumento. Se efectuó una exploración de los defectos en la superficie topográfica y determinados movimientos estructurales en cada material, con el propósito de evaluar los efectos de los ciclos de reutilización sobre el dispositivo médico. El experimento se realizó mediante el enfoque "QUALY" EIA/CES [1]. El estudio concluye que cuatro ciclos de reprocesado implican algunos cambios que no son estadísticamente representativos. Se detectaron defectos en la superficie del cable; igualmente, se observó un residuo superficial agresivo después de cuatro ciclos de reprocesamiento en la punta. No se observaron cambios estructurales en la cadena polimérica de la cuerda.


Os lápis de diatermia são um dos dispositivos mais utilizados em todo o mundo médico, uma condição que aumenta a sua chance de ser reprocessados com os pacientes. O lápis de diatermia tem diferentes partes (cabo, ponta, aderência, linhas de energia), que são compostas de materiais diferentes. A fim de identificar o comportamento de dispositivos médicos é necessário caracterizar todos tais materiais no instrumento. Uma varredura de defeitos foi realizado na superfície topográfica e certos movimentos estruturais em cada material, com o objetivo de avaliar os efeitos dos ciclos de reutilização no dispositivo médico. O experimento foi realizado utilizando o EIA/CES [1] abordagem "QUALY". O estudo conclui que quatro ciclos de reprocessamento envolvem algumas mudanças que não são estatisticamente representativa. Os defeitos foram detectados na superfície do cabo; do mesmo modo, um resíduo de superfície agressivo foi observada após quatro ciclos na ponta reprocessamento. Não foram observadas alterações estruturais na cadeia do polímero da corda.

18.
Rev. bras. parasitol. vet ; 23(2): 251-254, 06/2014. graf
Article in English | LILACS | ID: lil-714797

ABSTRACT

The genus Habronema has four valid species, of which only two are properly known. The present study aimed to describe in detail the morphology of Habronema clarki through optical and scanning electron microscopy analyses. Our results showed that the labial morphology of this parasite is closer to H. muscae than to H. microstoma. Even so, the characteristic pseudolabia and the slightly convex border of the dorsal and ventral lips are sufficient to distinguish these nematodes. Additional morphological data are presented, thus contributing to the knowledge on this little known nematode. In addition, this study provides new locality records for this species.


O gênero Habronema tem quatro espécies válidas, das quais apenas duas são propriamente conhecidas. O presente estudo visa descrever em detalhes a morfologia de Habronema clarki por meio de microscopia eletrônica de varredura e de luz. Os resultados demonstram que a morfologia labial do parasita é mais próxima de H. muscae que de H. microstoma. Ainda assim, os pseudolábios característicos e a borda discretamente convexa dos lábios dorsal e ventral são suficientes para se diferenciar esses nematódeos. Dados morfológicos adicionais são apresentados, contribuindo ao conhecimento deste nematódeo pouco conhecido. Em adição, este estudo representa um novo registro de localidade para a espécie.


Subject(s)
Animals , Female , Male , Rodentia/parasitology , Spirurida/anatomy & histology , Spirurida/physiology , Brazil , Parasites
19.
R. bras. Parasitol. Vet. ; 23(2): 251-254, 06/2014. graf
Article in English | VETINDEX | ID: vti-26880

ABSTRACT

The genus Habronema has four valid species, of which only two are properly known. The present study aimed to describe in detail the morphology of Habronema clarki through optical and scanning electron microscopy analyses. Our results showed that the labial morphology of this parasite is closer to H. muscae than to H. microstoma. Even so, the characteristic pseudolabia and the slightly convex border of the dorsal and ventral lips are sufficient to distinguish these nematodes. Additional morphological data are presented, thus contributing to the knowledge on this little known nematode. In addition, this study provides new locality records for this species.


O gênero Habronema tem quatro espécies válidas, das quais apenas duas são propriamente conhecidas. O presente estudo visa descrever em detalhes a morfologia de Habronema clarki por meio de microscopia eletrônica de varredura e de luz. Os resultados demonstram que a morfologia labial do parasita é mais próxima de H. muscae que de H. microstoma. Ainda assim, os pseudolábios característicos e a borda discretamente convexa dos lábios dorsal e ventral são suficientes para se diferenciar esses nematódeos. Dados morfológicos adicionais são apresentados, contribuindo ao conhecimento deste nematódeo pouco conhecido. Em adição, este estudo representa um novo registro de localidade para a espécie.


Subject(s)
Animals , Male , Female , Rodentia/parasitology , Spirurida/anatomy & histology , Spirurida/physiology , Brazil , Parasites
20.
Int. j. morphol ; 31(4): 1439-1443, Dec. 2013. ilus
Article in English | LILACS | ID: lil-702330

ABSTRACT

Neuroleptic drugs such as haloperidol has side effects on extrapyramidal pathways. Tardive Dyskinesia is the most important complication. The most characteristic feature of this Tardive Dyskinesia is involuntary movements of mouth and face. In regard to this problem, the induction of gliosis and cell death in the nervous tissue are considered. In this study, adult Sprague-Dawley rats were used as experimental models. Rats were divided into control and experimental groups. The rats were kept in the animal house under standard conditions during experiments. The control rats were intraperitoneally treated with normal saline for 6 days. The experimental samples were treated for the same time with 2, 5 and 10 mg haloperidol. After the trial period, the rats were killed following general anesthesia and their brains were removed after perfusion with a 4 percent formalin solution. Then, 1 mm cuts of the brains were obtained. After that, 5 um tissue sections were prepared and stained with hematoxylin and eosin. The stained sections were examined by optical microscopy. The results showed that the short-term use of haloperidol does not lead to gliosis process in the rat cerebral cortex. The short-term use of 10 mg haloperidol results in cell death in the rat cerebral cortex. Cell death was not observed in the control group and the groups that had received 2 mg and 5 mg doses of haloperidol. According to previous studies, it can be concluded that the gliosis process is induced in the cerebral cortex only following the long-term use of haloperidol. It is considered as a secondary cause of the neuroleptic drugs side effects. The primary cause of these side effects is the induction of cell death in neurons.


Los fármacos neurolépticos como el haloperidol tiene efectos secundarios sobre las vías extrapiramidales. La discinesia tardía es la complicación más importante. El rasgo más característico de esta discinesia tardía son movimientos involuntarios de la boca y cara. En lo que respecta a este problema, se consideran la inducción de gliosis y muerte celular en el tejido nervioso. En este estudio, fueron utilizados ratas Sprague - Dawley adultas como modelos experimentales. Las ratas se dividieron en grupos control y experimentales, y se mantuvieron en condiciones estándar durante los experimentos. Las ratas control fueron tratadas por vía intraperitoneal con solución salina normal durante 6 días, y las experimentales durante el mismo tiempo con 2 , 5 y 10 mg de haloperidol. Luego, las ratas se sacrificaron y sus cerebros se extrajeron después de la perfusión con una solución de formalina al 4 por ciento, obteniendo cortes de 1 mm de los cerebros. Se prepararon y se tiñeron con hematoxilina y eosina en secciones de tejido de 5 micras, y se examinaron por microscopía óptica. Se observó que el uso a corto plazo del haloperidol no conduce a proceso de gliosis en la corteza cerebral de rata. El uso a corto plazo de 10 mg de haloperidol produjo muerte celular en la corteza cerebral de rata. La muerte celular no se observó en el grupo control ni en los grupos que habían recibido 2 y 5 mg de haloperidol. De acuerdo con estudios anteriores, se concluye que el proceso de gliosis se induce en la corteza cerebral sólo tras el uso a largo plazo de exposición al haloperidol. Se considera como una causa secundaria de los efectos adversos de los fármacos neurolépticos. La principal causa de estos efectos secundarios, es la inducción de muerte celular en neuronas.


Subject(s)
Animals , Rats , Cerebral Cortex , Haloperidol/pharmacology , Cell Death , Apoptosis , In Situ Nick-End Labeling , Rats, Sprague-Dawley
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