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1.
Food Chem ; : 125878, 2019 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-31771910

RESUMO

ß-Carotene is a natural nutrient that serves as a natural food colorant. However, the weak physical stability restricts its development in food industrial production. Here, the influences of a variety of external environmental conditions on the stability of ß-carotene enriched zein-carboxymethyl chitosan (CMCS)-tea polyphenols (TP) ternary composite nanoparticles were investigated. Compared with zein unitary and zein-CMCS binary complexes, it was interesting to note that ternary complexes had the best stability against color fading and there was little impact on its nanoparticle size during storage with change in temperature. Besides excellent antioxidant properties, ternary complexes were extremely effective in inhibiting ß-carotene color degradation when exposed to ultraviolet light. Based on our results, the novel zein-CMCS-TP nanoparticles are expected to be an effective delivery system to encapsulate hydrophobic bioactive compounds, which is a promising approach to improve their storage stability against external environmental stresses.

2.
J Biomed Inform ; 100: 103319, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31655272

RESUMO

To provide natural simulated objects and intuitive user interaction in medical education and training, we propose a naked eye 3D display and interaction system. The current 3D rendering algorithms for naked eye 3D displays are not suitable for medical use, due to the requirements of displaying and interacting with high quality medical images and simulating soft tissues. Because the traditional 3D rendering procedure and vertex indexing in collision detection require substantial computing power when using a naked eye 3D display, the current method cannot achieve fluent displays and interactions. Thus, we develop a novel octree-based 3D rendering and interaction algorithm for high quality medical models to improve the rendering rate and obtain smooth human machine interactions when using the naked eye 3D display device. We also valuate the soft-body phantom simulation of the naked eye 3D display device by combining the traditional 3D rendering algorithm with the elastic 3D simulation to simulate deformable tissues. We integrate an incremental interaction method and a Kalman filter-based hand tracking method to achieve a larger user interaction range and robust hand tracking. We used the proposed system to perform human-computer interactions with rigid phantoms and soft-body phantoms. The experimental results showed that the proposed rendering algorithm for rigid phantoms could achieve higher rendering performance (50 FPS) than the traditional rendering algorithm (9.8 FPS). The user experiments showed that the 3D simulation system equipped with the enhanced rendering algorithm could achieve fluent interactions when using the naked eye 3D display, thus promoting education experiences and reducing task completion times.

3.
Food Funct ; 10(2): 635-645, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30648709

RESUMO

The design of zein-based nanoparticles to encapsulate bioactive molecules has gained great attention in recent years. However, the use of ethanol to dissolve zein presents flammability concerns and the scale-up production of zein-based nanoparticles is also a concern. In our study, propolis loaded zein/caseinate/alginate nanoparticles were fabricated using a facile one-step procedure: a well-blended solution was prepared containing deprotonated propolis, soluble zein, dissociated sodium caseinate micelles (NaCas) and alginate at alkaline pH, and then this alkaline solution was added to 0.1 M citrate buffer (pH 3.8) to fabricate composite nanoparticles without using organic solvents and sophisticated equipment. During acidification, the alginate molecules adsorbed on the zein/NaCas surfaces by electrostatic complexation, which improved the stability towards aggregation of zein/NaCas nanoparticles under gastrointestinal (GI) or acidic pH. The nanoparticles prepared under the optimized method (method 3 sample) were of spherical morphology with a particle size around 208 nm and a negative zeta potential around -27 mV. The encapsulation efficiency (EE) and loading capacity (LC) of propolis reached 86.5% and 59.6 µg mg-1 by zein/NaCas/alginate nanoparticles, respectively. These nanoparticles were shown to be stable towards aggregation over a wide range of pH values (2-8) and salt concentrations (0-300 mM NaCl). Compared to free propolis, the bioaccessibility of propolis encapsulated with nanoparticles was increased to 80%. Our results showed a promising clean and scalability strategy to encapsulate hydrophobic nutraceuticals for applications in foods, supplements, and pharmaceuticals.


Assuntos
Alginatos/química , Caseínas/química , Nanopartículas/química , Própole/química , Zeína/química , Tecnologia de Alimentos , Microscopia Eletrônica de Transmissão
4.
IEEE J Biomed Health Inform ; 23(6): 2483-2493, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-30530379

RESUMO

Augmented reality (AR) surgical navigation systems based on image overlay have been used in minimally invasive surgery. However, conventional systems still suffer from a limited viewing zone, a shortage of intuitive three-dimensional (3D) image guidance and cannot be moved freely. To fuse the 3-D overlay image with the patient in situ, it is essential to track the overlay device while it is moving. A direct line-of-sight should be maintained between the optical markers and the tracker camera. In this study, we propose a moving-tolerant AR surgical navigation system using autostereoscopic image overlay, which can avoid the use of the optical tracking system during the intraoperative period. The system captures binocular image sequences of environmental change in the operation room to locate the overlay device, rather than tracking the device directly. Therefore, it is no longer required to maintain a direct line-of-sight between the tracker and the tracked devices. The movable range of the system is also not limited by the scope of the tracker camera. Computer simulation experiments demonstrate the reliability of the proposed moving-tolerant AR surgical navigation system. We also fabricate a computer-generated integral photography-based 3-D overlay AR system to validate the feasibility of the proposed moving-tolerant approach. Qualitative and quantitative experiments demonstrate that the proposed system can always fuse the 3-D image with the patient, thus, increasing the feasibility and reliability of traditional 3-D overlay image AR surgical navigation systems.

5.
J Opt Soc Am A Opt Image Sci Vis ; 35(9): 1567-1574, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30183012

RESUMO

Integral photography (IP) is one of the most promising 3D displays that can achieve a full parallax 3D display without glasses. There is a great need to render a correct, high-precision 3D image from an IP display. To achieve a correct 3D display, calibration is needed to correct optical misalignment and optical aberrations, while it is challenging to achieve correct mapping between a microlens array and matrix display. We propose an IP calibration method for a 3D autostereoscopic integral photography display based on a sparse camera array. Our method distinguishes itself from previous methods by estimating parameters for a dense correspondence map of an IP display with a relatively flexible setup and high precision in a reasonable time cost. We also propose a workflow to enable our method to handle both a visible and invisible microlens array and obtain a great outcome. One prototype is fabricated to evaluate the feasibility of the proposed method. Moreover, we evaluate our proposed method in geometry accuracy and image quality.

6.
IEEE Trans Biomed Eng ; 65(2): 378-389, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29346106

RESUMO

We develop a spatial position measurement system using three-dimensional (3-D) image marker-based tracking tools targeted at surgical navigation in minimally invasive surgery. We generate 3-D image markers with spatial information encoded to 2-D images, design tracking tools with the 3-D image markers, and analyze the tracking tools' theoretical spatial errors, which are primarily limited by the spatial distribution of reconstructed fiducial 3-D markers. A pattern analysis-based positional measurement algorithm is developed to calculate the tool's spatial information using its spatial configuration. Evaluation experiments were conducted to demonstrate the accuracy and effectiveness of the proposed system. Furthermore, surgical navigation feasibility studies were performed. With a patient-image registration algorithm, a navigation interface that shows preoperative medical data and intraoperative information about the tool can intuitively and accurately assist surgeons. The results demonstrate that the proposed tracking tools, which have compact volume and spatial positional information, are of potential use in minimally invasive surgery in a limited space.


Assuntos
Imagem Tridimensional/métodos , Cirurgia Assistida por Computador/métodos , Algoritmos , Marcadores Fiduciais , Mãos/diagnóstico por imagem , Mãos/cirurgia , Humanos , Imagens de Fantasmas , Crânio/diagnóstico por imagem , Crânio/cirurgia
7.
IEEE Trans Vis Comput Graph ; 24(9): 2600-2609, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-28961116

RESUMO

We propose a computer generated integral photography (CGIP) method that employs a lens based rendering (LBR) algorithm for super-multiview displays to achieve higher frame rates and better image quality without pixel resampling or view interpolation. The algorithm can utilize both fixed and programmable graphics pipelines to accelerate CGIP rendering and inter-perspective antialiasing. Two hardware prototypes were fabricated with two high-resolution liquid crystal displays and micro-lens arrays (MLA). Qualitative and quantitative experiments were performed to evaluate the feasibility of the proposed algorithm. To the best of our knowledge, the proposed LBR method outperforms state-of-the-art CGIP algorithms relative to rendering speed and image quality with our super-multiview hardware configurations. A demonstration experiment was also conducted to reveal the interactivity of a super-multiview display utilizing the proposed algorithm.

8.
J Opt Soc Am A Opt Image Sci Vis ; 34(5): 804-812, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28463324

RESUMO

Quality of three-dimensional (3D) autostereoscopic displays is mainly influenced by the mismatch between the optical apparatus setups and image generation algorithms. In this paper, we take the optical apparatus setups into consideration and present an accurate 3D autostereoscopic display method using optimized parameters through quantitative calibration. Rotational and translational alignments are operated quantitatively to rectify the optical apparatus. In addition, the main parameters in a 3D display are evaluated for accurate 3D image rendering. Using the proposed method, the 3D autostereoscopic display can be calibrated quantitatively and provide 3D images with accurate spatial information. Experiments verified the availability and feasibility of the proposed method.

9.
J Biomed Inform ; 71: 154-164, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28533140

RESUMO

Three-dimensional (3D) visualization of preoperative and intraoperative medical information becomes more and more important in minimally invasive surgery. We develop a 3D interactive surgical visualization system using mobile spatial information acquisition and autostereoscopic display for surgeons to observe surgical target intuitively. The spatial information of regions of interest (ROIs) is captured by the mobile device and transferred to a server for further image processing. Triangular patches of intraoperative data with texture are calculated with a dimension-reduced triangulation algorithm and a projection-weighted mapping algorithm. A point cloud selection-based warm-start iterative closest point (ICP) algorithm is also developed for fusion of the reconstructed 3D intraoperative image and the preoperative image. The fusion images are rendered for 3D autostereoscopic display using integral videography (IV) technology. Moreover, 3D visualization of medical image corresponding to observer's viewing direction is updated automatically using mutual information registration method. Experimental results show that the spatial position error between the IV-based 3D autostereoscopic fusion image and the actual object was 0.38±0.92mm (n=5). The system can be utilized in telemedicine, operating education, surgical planning, navigation, etc. to acquire spatial information conveniently and display surgical information intuitively.


Assuntos
Processamento de Imagem Assistida por Computador , Imagem Tridimensional , Procedimentos Cirúrgicos Operatórios , Telemedicina , Algoritmos , Humanos
10.
IEEE Trans Biomed Eng ; 64(8): 1815-1825, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-27834634

RESUMO

OBJECTIVE: Precise minimally invasive surgery (MIS) has significant advantages over traditional open surgery in clinic. Although pre-/intraoperative diagnosis images can provide necessary guidance for therapy, hand-eye discoordination occurs when guidance information is displayed away from the surgical area. In this study, we introduce a real three-dimensional (3-D) see-through guidance system for precision surgery. METHODS: To address the resolution and viewing angle limitation as well as the accuracy degradation problems of autostereoscopic 3-D display, we design a high quality and high accuracy 3-D integral videography (IV) medical image display method. Furthermore, a novel see-through microscopic device is proposed to assist surgeons with the superimposition of real 3-D guidance onto the surgical target is magnified by an optical visual magnifier module. RESULTS: Spatial resolutions of 3-D IV image in different depths have been increased 50%∼70%, viewing angles of different image sizes have been increased 9%∼19% compared with conventional IV display methods. Average accuracy of real 3-D guidance superimposed on surgical target was 0.93 mm ± 0.41 mm. Preclinical studies demonstrated that our system could provide real 3-D perception of anatomic structures inside the patient's body. CONCLUSION: The system showed potential clinical feasibility to provide intuitive and accurate in situ see-through guidance for microsurgery without restriction on observers' viewing position. SIGNIFICANCE: Our system can effectively improve the precision and reliability of surgical guidance. It will have wider applicability in surgical planning, microscopy, and other fields.


Assuntos
Microcirurgia/instrumentação , Procedimentos Cirúrgicos Minimamente Invasivos/instrumentação , Neuronavegação/instrumentação , Interface Usuário-Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
11.
Opt Express ; 23(8): 9812-23, 2015 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-25969022

RESUMO

In this paper, we present a polyhedron-shaped floating autostereoscopic display viewable from 360 degrees using integral photography (IP) and multiple semitransparent mirrors. IP combined with polyhedron-shaped multiple semitransparent mirrors is used to achieve a 360 degree viewable floating three-dimensional (3D) autostereoscopic display, having the advantage of being able to be viewed by several observers from various viewpoints simultaneously. IP is adopted to generate a 3D autostereoscopic image with full parallax property. Multiple semitransparent mirrors reflect corresponding IP images, and the reflected IP images are situated around the center of the polyhedron-shaped display device for producing the floating display. The spatial reflected IP images reconstruct a floating autostereoscopic image viewable from 360 degrees. We manufactured two prototypes for producing such displays and performed two sets of experiments to evaluate the feasibility of the method described above. The results of our experiments showed that our approach can achieve a floating autostereoscopic display viewable from surrounding area. Moreover, it is shown the proposed method is feasible to facilitate the continuous viewpoint of a whole 360 degree display without flipping.

12.
Conf Proc IEEE Eng Med Biol Soc ; 2015: 4210-3, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26737223

RESUMO

Image guided surgery has been used in clinic to improve the surgery safety and accuracy. Augmented reality (AR) technique, which can provide intuitive image guidance, has been greatly evolved these years. As one promising approach of surgical AR systems, integral videography (IV) autostereoscopic image overlay has achieved accurate fusion of full parallax guidance into surgical scene. This paper describes an image enhanced high-accuracy IV overlay system. A flexible optical image enhancement system (IES) is designed to increase the resolution and quality of IV image. Furthermore, we introduce a novel IV rendering algorithm to promote the spatial accuracy with the consideration of distortion introduced by micro lens array. Preliminary experiments validated that the image accuracy and resolution are improved with the proposed methods. The resolution of the IV image could be promoted to 1 mm for a micro lens array with pitch of 2.32 mm and IES magnification value of 0.5. The relative deviation of accuracy in depth and lateral directions are -4.68 ± 0.83% and -9.01 ± 0.42%.


Assuntos
Algoritmos , Aumento da Imagem/métodos , Cirurgia Assistida por Computador/métodos , Cirurgia Vídeoassistida/métodos , Humanos , Imagem Tridimensional/métodos , Cirurgia Assistida por Computador/instrumentação , Cirurgia Vídeoassistida/instrumentação
13.
Conf Proc IEEE Eng Med Biol Soc ; 2015: 4226-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26737227

RESUMO

Autostereoscopic has long been proposed to fulfill medical display in image-guided surgery and clinical education to provide more intuitive position information of clinical interest zone thus improving surgery safety and accuracy. As one category of flexible autostereoscopic 3D display, computer generated integral photography (CGIP) has been studied in medical application by many researches for its convenience and cost-efficiency. However, IP still suffers from inaccurate light field reconstruction, which limits its practicality in surgery. In this paper, we propose and apply a flexible fish-eye model based micro lens array (MLA) distortion calibration method and pre-distorted retracing rendering algorithm to render elemental image array (EIA) of CGIP. Furthermore, we also evaluate light field of the proposed algorithm in depth cue, and signal noise ratio of IP images by phantom experiment.


Assuntos
Imagem Tridimensional/métodos , Fotografação/métodos , Crânio/patologia , Cirurgia Assistida por Computador/métodos , Algoritmos , Calibragem , Diagnóstico por Imagem/métodos , Desenho de Equipamento , Humanos , Lentes , Modelos Estatísticos , Imagens de Fantasmas , Processamento de Sinais Assistido por Computador , Razão Sinal-Ruído
14.
Mol Cell Endocrinol ; 392(1-2): 14-22, 2014 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-24859603

RESUMO

Poly(ADP-ribose) polymerase-1 (PARP-1) enzyme, as a sensor of DNA damage, could convert nicotinamide adenine dinucleotide (NAD) into long poly(ADP-ribose) chains and regulate many cellular processes, including DNA repair, gene transcription, cell survival and chromatin remodeling. However, excessive activation of PARP-1 depletes its substrate NAD and leads to cell death. Mounting evidences have shown that PARP-1 overactivation plays a pivotal role in the pathogenesis of cardiac hypertrophy and heart failure. In present study, a novel PARP-1 inhibitor AG-690/11026014 (6014) was identified based on virtual screening and validated by bioassay. Our results further showed that 6014 prevented the cardiomyocytes from AngII-induced hypertrophy, accompanying attenuation of the mRNA and protein expressions of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP), and reduce in the cell surface area. Additionally, 6014 reversed the depletion ofcellular NAD and SIRT6 deacetylase activity induced by AngII in cardiomyocytes. These observations suggest that anti-hypertrophic effect of 6014 might be partially attributed to the rescue of NAD depletion and subsequent restoring of SIRT6 activity by inhibition of PARP-1. Moreover, 6014 attenuated the generation of oxidative stress via suppression of NADPH oxidase 2 and 4, which might probably contribute to the inhibition of PARP-1.


Assuntos
Cardiomegalia/enzimologia , Cardiomegalia/prevenção & controle , Cardiotônicos/uso terapêutico , Citoproteção/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Miócitos Cardíacos/patologia , Inibidores de Poli(ADP-Ribose) Polimerases , Tioglicolatos/farmacologia , Xantinas/farmacologia , Angiotensina II , Animais , Cardiotônicos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/análise , Inibidores Enzimáticos/química , Humanos , Concentração Inibidora 50 , Glicoproteínas de Membrana/metabolismo , Simulação de Acoplamento Molecular , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/enzimologia , NAD/metabolismo , NADPH Oxidase 2 , NADPH Oxidase 4 , NADPH Oxidases/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Proteínas Recombinantes/metabolismo , Sirtuínas/metabolismo , Tioglicolatos/análise , Tioglicolatos/química , Regulação para Cima/efeitos dos fármacos , Xantinas/análise , Xantinas/química
15.
J Chromatogr A ; 1256: 213-21, 2012 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-22883157

RESUMO

Phenyl-ended hyperbranched carbosilane (HBC) is synthesized and immobilized onto the inner wall of a fused silica capillary column using a sol-gel process. The hybrid coating layer formed is used as a stationary phase for gas chromatography (GC) and as an adsorption medium for solid phase microextraction (SPME). Trifluoroacetic acid, as a catalyst in this process, helps produce a homogeneous hybrid coating layer. This result is beneficial for better column chromatographic performances, such as high efficiency and high resolution. Extraction tests using the novel hybrid layer show an extraordinarily large adsorption capacity and specific adsorption behavior for aromatic compounds. A 1 ppm trace level detectability is obtained with the SPME/GC work model when both of the stationary phase and adsorption layer bear a hyperbranched structure. A large amount of phenyl groups and a low viscosity of hyperbranched polymers contribute to these valuable properties, which are important to environment and safety control, wherein detection sensitivity and special adsorption behavior are usually required.


Assuntos
Cromatografia Gasosa , Silanos/química , Dióxido de Silício/química , Microextração em Fase Sólida , Adsorção , Catálise , Termogravimetria , Ácido Trifluoracético/química
16.
Chem Commun (Camb) ; (10): 1258-60, 2009 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-19240892

RESUMO

The hydrate tetrabutylammonium hydroxide ionic liquid is an efficient ILP for the controlled fabrication of zinc oxide particles with unusual nanostructures.


Assuntos
Líquidos Iônicos/química , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Óxido de Zinco/química , Microscopia Eletrônica de Varredura
17.
J Colloid Interface Sci ; 329(1): 48-53, 2009 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-18922543

RESUMO

High molecular weight powdery polyacrylonitrile (PAN) polymers were prepared by aqueous suspension polymerization employing itaconic acid (IA) as comonomer and alpha,alpha(')-azobisisobutyronitrile (AIBN) as initiator at 60 degrees C. PAN polymers obtained with different monomer ratios were characterized by EA, DSC, FTIR and XRD. It is investigated that the oxygen element content in PAN polymers increased with the increase of required IA amounts in the feed and heat-treatment temperatures. DSC curves of PAN copolymers exhibited the triplet character, owing to the exothermic cyclization and oxidative reactions during heat-treatment process. Introduction of IA in the feed relaxed exothermic reactions of PAN polymers under air atmosphere. Structure and crystallinity changes were affected by required IA amounts in the feed and enhancement of heat-treatment temperatures. The characteristic functional groups (including C[triple bond]N, C=O, CH(2)) presented in FTIR spectra of PAN polymers indicated copolymerization reaction of AN and IA. Existence of some organic groups (C-O, C=C and/or C=N) indicated formation of ladderlike structure during heat-treatment process. PAN homopolymer had the better crystallinity (mainly peak intensity and peak area around 2theta = 17 degrees) than most RT-PAN copolymers. When heat-treatment temperature is around 210 degrees C, peak intensity, peak area, L(c) and CI of HT-PAN polymers corresponding to samples 1# and 2# got maxima, while crystallinity became weak at higher heat-treatment temperatures.

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