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1.
J Biophotonics ; 12(12): e201900218, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31452335

RESUMO

Modern document protection relies on the simultaneous combination of many optical features with micron and submicron structures, whose complexity is the main obstacle for unauthorized copying. In that sense, documents are best protected by the diffractive optical elements generated lithographically and mass-produced by embossing. The problem is that the resulting security elements are identical, facilitating mass-production of both original and counterfeited documents. Here, we prove that each butterfly wing-scale is structurally and optically unique and can be used as an inimitable optical memory tag and applied for document security. Wing-scales, exhibiting angular variability of their color, were laser-cut and bleached to imprint cryptographic information of an authorized issuer. The resulting optical memory tag is extremely durable, as verified by several century-old insect specimens still retaining their coloration. The described technique is simple, amenable to mass-production, low cost and easy to integrate within the existing security infrastructure.

2.
J Therm Biol ; 76: 126-138, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30143287

RESUMO

The insect cuticle serves a multitude of purposes, including: mechanical and thermal protection, water-repelling, acoustic signal absorption and coloration. The influence of cuticular structures on infrared radiation exchange and thermal balance is still largely unexplored. Here we report on the micro- and nanostructured setae covering the elytra of the longicorn beetle Rosalia alpina (Linnaeus, 1758) (Coleoptera: Cerambycidae) that help the insect to survive in hot, summer environments. In the visible part of the spectrum, scale-like setae, covering the black patches of the elytra, efficiently absorb light due to the radiation trap effect. In the infrared part of the spectrum, setae of the whole elytra significantly contribute to the radiative heat exchange. From the biological point of view, insect elytra facilitate camouflage, enable rapid heating to the optimum body temperature and prevent overheating by emitting excess thermal energy.


Assuntos
Exoesqueleto/química , Regulação da Temperatura Corporal , Besouros/anatomia & histologia , Animais , Temperatura Alta , Luz , Modelos Biológicos , Termografia
3.
Tumour Biol ; 39(7): 1010428317711654, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28718368

RESUMO

In recent years, it has been demonstrated that malignancy arises and advances through the molecular interplay between tumor cells and non-malignant elements of the tumor stroma, that is, fibroblasts and extracellular matrix. However, in contrast to the mounting evidence about the role of tumor stroma in the genesis and progression of the malignant disease, there are very few data regarding the uninvolved stromal tissue in the remote surrounding of the tumor. Using the objective morphometric approach in patients with adenocarcinoma, we demonstrate the remodeling of extracellular matrix of the lamina propria in the uninvolved rectal mucosa 10 and 20 cm away from the neoplasm. We show that the representation of basic extracellular matrix constituents (reticular and collagen fibers and ground substance) is decreased. Also, the diameter of empty spaces that appear within the extracellular matrix of the lamina propria is increased. These spaces do not represent the blood or lymphatic vessel elements. Very likely, they reflect the development of tissue edema in the remote, uninvolved lamina propria of the mucosa in patients with the malignant tumor of the rectum. We hypothesize that the remodeling of extracellular matrix in lamina propria of the rectal mucosa may increase its stiffness, modulating the mechano-signal transduction, and thus promote the progression of the malignant disease.


Assuntos
Adenocarcinoma/patologia , Matriz Extracelular/patologia , Membrana Mucosa/patologia , Neoplasias Retais/patologia , Idoso , Vasos Sanguíneos/patologia , Carcinogênese/patologia , Progressão da Doença , Feminino , Humanos , Mucosa Intestinal , Masculino
4.
J Biomed Opt ; 20(1): 016010, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25574994

RESUMO

We performed a study of the nonlinear optical properties of chemically purified chitin and insect cuticle using two-photon excited autofluorescence (TPEF) and second-harmonic generation (SHG) microscopy. Excitation spectrum, fluorescence time, polarization sensitivity, and bleaching speed were measured. We have found that the maximum autofluorescence signal requires an excitation wavelength below 850 nm. At longer wavelengths, we were able to penetrate more than 150-um deep into the sample through the chitinous structures. The excitation power was kept below 10 mW (at the sample) in order to diminish bleaching. The SHG from the purified chitin was confirmed by spectral- and time-resolved measurements. Two cave-dwelling, depigmented, insect species were analyzed and three-dimensional images of the cuticular structures were obtained.


Assuntos
Quitina/química , Besouros/química , Microscopia de Fluorescência por Excitação Multifotônica/instrumentação , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Animais , Artrópodes/química , Cavernas , Desenho de Equipamento , Imagem Tridimensional/métodos , Dinâmica não Linear
5.
J Biomed Opt ; 19(12): 127005, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25517257

RESUMO

We describe a method for dual-view biomechanical strain measurements of highly asymmetrical biological objects, like teeth or bones. By using a spherical mirror, we were able to simultaneously record a digital hologram of the object itself and the mirror image of its (otherwise invisible) rear side. A single laser beam was sufficient to illuminate both sides of the object, and to provide a reference beam. As a result, the system was mechanically very stable, enabling long exposure times (up to 2 min) without the need for vibration isolation. The setup is simple to construct and adjust, and can be used to interferometrically observe any object that is smaller than the mirror diameter. Parallel data processing on a CUDA-enabled (compute unified device architecture) graphics card was used to reconstruct digital holograms and to further correct image distortion. We used the setup to measure the deformation of a tooth due to mastication forces. The finite-element method was used to compare experimental results and theoretical predictions.


Assuntos
Fenômenos Biomecânicos/fisiologia , Holografia/instrumentação , Holografia/métodos , Interferometria/instrumentação , Interferometria/métodos , Dente Pré-Molar/fisiologia , Desenho de Equipamento , Análise de Elementos Finitos , Humanos , Processamento de Imagem Assistida por Computador , Mastigação/fisiologia
6.
Microsc Res Tech ; 75(7): 968-76, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22392855

RESUMO

Apatura ilia (Denis and Schiffermüller, 1775) and A. iris (Linnaeus, 1758) are fascinating butterflies found in the Palaearctic ecozone (excepting the north of Africa). The wings of these insects are covered with a great number of two types of scales positioned like roof tiles. Type I scales are on the surface, while type II scales are situated below them. The structural color of the type I scales is recognized only on the dorsal side of both the fore and hind wings of the males of the aforementioned species. Both types of scales are responsible for pigment color of the wings, but iridescence is observed only in the type I scales. The brilliant structural color is due to a multilayer structure. The features of the scales, their dimensions and fine structure were obtained using scanning electron microscopy. Cross sections of the scales were then analyzed by transmission electron microscopy. The scales of the "normal" and clytie forms of A. ilia have a different nanostructure, but are of the same type. A similar type of structure, but with a different morphology, was also noticed in A. iris. The scales of the analyzed species resemble the scales of tropical Morpho butterflies.


Assuntos
Borboletas/ultraestrutura , Asas de Animais/ultraestrutura , África , Animais , Feminino , Masculino , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanoestruturas/ultraestrutura
7.
Lasers Surg Med ; 42(4): 338-47, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20432283

RESUMO

BACKGROUND AND OBJECTIVE: Laser phototherapy could be potentially used for cancer treatment, but the mechanisms of laser-induced cell death are not completely understood. Autophagy is the process in which the damaged cellular proteins and organelles are engulfed by and destroyed in acidified multiple-membrane vesicles. The aim of the present study was to investigate the role of autophagy in laser-induced tumor cell death in vitro. STUDY DESIGN/MATERIALS AND METHODS: The monolayers of U251 human glioma tumor cells were exposed to 532 nm laser light from a single mode frequency-doubled Nd-YVO4 laser. A flattened Gaussian radial profile of laser beam (0.5-4 W) was used to uniformly illuminate entire colony of cells for various amounts of time (15-120 seconds) in the absence of cell culture medium. The cells were grown for 24 hours and the cell viability was determined by crystal violet or MTT assay. The presence of autophagy was assessed after 16 hours by fluorescence microscopy/flow cytometric analysis of acridine orange-stained autophagolysosomes and Western blot analysis of the autophagosome-associated LC3-II protein. The concentration of the principal pro-autophagic protein beclin-1 was determined after 6 hours by cell-based ELISA. RESULTS: The intracytoplasmic accumulation of autophagic vesicles, increase in LC3-II and up-regulation of beclin-1 expression were clearly observed under irradiation conditions that caused approximately 50% cytotoxicity. Post-irradiation addition of three different autophagy inhibitors (bafilomycin A1, chloroquine, or wortmannin) further increased the laser-induced cytotoxicity, without affecting non-irradiated cells. CONCLUSIONS: These data indicate that beclin-1-dependent induction of autophagy can protect glioma cells from laser-mediated cytotoxicity.


Assuntos
Autofagia , Glioma/patologia , Terapia a Laser/métodos , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Proteína Beclina-1 , Western Blotting , Proliferação de Células , Sobrevivência Celular , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Humanos , Hipertermia Induzida , Técnicas In Vitro , Terapia a Laser/instrumentação , Lasers de Estado Sólido , Microscopia de Fluorescência , Necrose , Células Tumorais Cultivadas , Regulação para Cima
8.
Appl Opt ; 46(35): 8527-32, 2007 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-18071385

RESUMO

Gelatin sensitized with tot'hema and eosin (compounds used in medical therapy) appears to be an excellent material for microlens fabrication. Lenses are produced by irradiation with a 532 nm laser beam. Aspheric concave lenses are formed rapidly with low power radiation. The lens profile is analyzed, as well as imaging properties. Physics of lens formation is also proposed. All material constituents are nonpoisonous, resulting in an environmentally safe, low toxicity material.


Assuntos
Projeto Auxiliado por Computador , Amarelo de Eosina-(YS)/química , Gelatina/química , Compostos de Ferro/química , Lentes , Desenho de Equipamento , Análise de Falha de Equipamento
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