scholarly journals Ratiometric Luminescent Nanoprobes Based on Ruthenium and Terbium-Containing Metallopolymers for Intracellular Oxygen Sensing

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1290 ◽  
Author(s):  
Wu-xing Zhao ◽  
Chao Zhou ◽  
Hong-shang Peng
Keyword(s):  
Three Dimensional ◽  
Optoelectronic System ◽  
Typical Size ◽  
Detection Approach ◽  
Nanoprecipitation Method ◽  
Oxygen Sensitive ◽  
Wavelength Emission ◽  
Branched Copolymer ◽  
Oxygen Probes ◽  
Biomedical Field

A collection of luminescent metal complexes have been widely used as oxygen probes in the biomedical field. However, single intensity-based detection approach usually suffered from errors caused by the signal heterogeneity or fluctuation of the optoelectronic system. In this work, respective ruthenium (II) and terbium (III) complexes were chosen to coordinate a bipyridine-branched copolymer, so that to produce oxygen-sensitive metallopolymer (Ru-Poly) and oxygen-insensitive metallopolymer (Tb-Poly). Based on the hydrophobic Ru-Poly and Tb-Poly, a ratiometric luminescent oxygen nanoprobe was facilely prepared by a nanoprecipitation method. The nanoprobes have a typical size of ~100 nm in aqueous solution, exhibiting a green-red dual-wavelength emission under the excitation of 300 nm and 460 nm, respectively. The red emission is strongly quenched by dissolved oxygen while the green one is rather stable, and the ratiometric luminescence was well fitted by a linear Stern–Volmer equation. Using the ratiometric biocompatible nanoprobes, the distribution of intracellular oxygen within three-dimensional multi-cellular tumor spheroids was successfully imaged.

scholarly journals 3D Robot Vision System through 2D Shape Based Matching Using Gaussian Smoothing for Gluing Application

2018 ◽  
Vol 7 (4.33) ◽  
pp. 487
Author(s):  
Mohamad Haniff Harun ◽  
Mohd Shahrieel Mohd Aras ◽  
Mohd Firdaus Mohd Ab Halim ◽  
Khalil Azha Mohd Annuar ◽  
Arman Hadi Azahar ◽  
...  
Keyword(s):  
Template Matching ◽  
Shape Matching ◽  
Vision System ◽  
Recognition Rate ◽  
Three Dimensional ◽  
Robot Vision ◽  
Region Of Interest ◽  
Gaussian Smoothing ◽  
Detection Approach ◽  
Vision Algorithm

This investigation is solely on the adaptation of a vision system algorithm to classify the processes to regulate the decision making related to the tasks and defect’s recognition. These idea stresses on the new method on vision algorithm which is focusing on the shape matching properties to classify defects occur on the product. The problem faced before that the system required to process broad data acquired from the object caused the time and efficiency slightly decrease. The propose defect detection approach combine with Region of Interest, Gaussian smoothing, Correlation and Template Matching are introduced. This application provides high computational savings and results in better recognition rate about 95.14%. The defects occur provides with information of the height which corresponds by the z-coordinate, length which corresponds by the y-coordinate and width which corresponds by the x-coordinate. This data gathered from the proposed system using dual camera for executing the three dimensional transformation.  

scholarly journals Luminescent Nanosensors for Ratiometric Monitoring of Three-Dimensional Oxygen Gradients in Laboratory and Clinical Pseudomonas aeruginosa Biofilms

2019 ◽  
Vol 85 (20) ◽  
Author(s):  
Megan P. Jewell ◽  
Anne A. Galyean ◽  
J. Kirk Harris ◽  
Edith T. Zemanick ◽  
Kevin J. Cash
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Temporal Variation ◽  
Complex Structure ◽  
Three Dimensional ◽  
Spatial And Temporal Variation ◽  
Content Type ◽  
Oxygen Penetration ◽  
Oxygen Gradients ◽  
Oxygen Sensitive

ABSTRACT Bacterial biofilms can form persistent infections on wounds and implanted medical devices and are associated with many chronic diseases, such as cystic fibrosis. These infections are medically difficult to treat, as biofilms are more resistant to antibiotic attack than their planktonic counterparts. An understanding of the spatial and temporal variation in the metabolism of biofilms is a critical component toward improved biofilm treatments. To this end, we developed oxygen-sensitive luminescent nanosensors to measure three-dimensional (3D) oxygen gradients, an application of which is demonstrated here with Pseudomonas aeruginosa biofilms. The method was applied here and improves on traditional one-dimensional (1D) methods of measuring oxygen profiles by investigating the spatial and temporal variation of oxygen concentration when biofilms are challenged with antibiotic attack. We observed an increased oxygenation of biofilms that was consistent with cell death from comparisons with antibiotic kill curves for PAO1. Due to the spatial and temporal nature of our approach, we also identified spatial and temporal inhomogeneities in the biofilm metabolism that are consistent with previous observations. Clinical strains of P. aeruginosa subjected to similar interrogation showed variations in resistance to colistin and tobramycin, which are two antibiotics commonly used to treat P. aeruginosa infections in cystic fibrosis patients. IMPORTANCE Biofilm infections are more difficult to treat than planktonic infections for a variety of reasons, such as decreased antibiotic penetration. Their complex structure makes biofilms challenging to study without disruption. To address this limitation, we developed and demonstrated oxygen-sensitive luminescent nanosensors that can be incorporated into biofilms for studying oxygen penetration, distribution, and antibiotic efficacy—demonstrated here with our sensors monitoring antibiotic impacts on metabolism in biofilms formed from clinical isolates. The significance of our research is in demonstrating not only a nondisruptive method for imaging and measuring oxygen in biofilms but also that this nanoparticle-based sensing platform can be modified to measure many different ions and small molecule analytes.

Micromechanical Modelling of Shape Memory Polymers

2008 ◽  
Vol 54 ◽  
pp. 137-142 ◽  
Author(s):  
Markus Böl ◽  
Stefanie Reese
Keyword(s):  
Shape Memory ◽  
Biomedical Applications ◽  
Three Dimensional ◽  
Coupled Model ◽  
Shape Memory Polymers ◽  
Material Behaviour ◽  
Thermomechanical Loading ◽  
Temperature Changes ◽  
Mechanical Interpretation ◽  
Biomedical Field

Shape memory materials represent a promising class of dual-shape materials that can move from one shape to another in response to a stimulus such as light, heat, electricity or magnetism. In this regard, the biomedical field is showing large interest in this class of materials, especially in shape memory polymers (SMPs), whose mechanical properties make them extremely attractive for many biomedical applications. However, diverse characteristics including also the mechanical behaviour are still part of research. In this contribution the shape memory properties of polymers will be quantified by cyclic thermomechanical investigations. One cycle includes the "programming" of the sample and the recovery of its permanent shape. To describe this phenomenon, a three-dimensional thermomechanical coupled model is proposed. This macromechanical constitutive model is based on the physical understanding of the material behaviour and a mechanical interpretation of the stress-strain-temperature changes observed during thermomechanical loading. The main focus of this work is the influence of both, the material constants and heat transfer boundary conditions on the response of shape memory polymers. Therefore we illustrate different general simulations as well as examples of application.

Aptamer-Based Targeted Drug Delivery Systems: Current Potential and Challenges

2020 ◽  
Vol 27 (13) ◽  
pp. 2189-2219 ◽  
Author(s):  
Fen He ◽  
Nachuan Wen ◽  
Daipeng Xiao ◽  
Jianhua Yan ◽  
Hongjie Xiong ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Targeted Drug Delivery ◽  
Drug Delivery Systems ◽  
Three Dimensional ◽  
Delivery Systems ◽  
Good Biocompatibility ◽  
Target Molecules ◽  
Biomedical Field ◽  
High Binding Affinity ◽  
Targeted Drug Delivery Systems

: Aptamers are single-stranded DNA or RNA with 20-100 nucleotides in length that can specifically bind to target molecules via formed three-dimensional structures. These innovative targeting molecules have attracted an increasing interest in the biomedical field. Compared to traditional protein antibodies, aptamers have several advantages, such as small size, high binding affinity, specificity, good biocompatibility, high stability and low immunogenicity, which all contribute to their wide application in the biomedical field. Aptamers can bind to the receptors on the cell membrane and mediate themselves or conjugated nanoparticles to enter into cells. Therefore, aptamers can be served as ideal targeting ligands for drug delivery. Since their excellent properties, different aptamer-mediated drug delivery systems had been developed for cancer therapy. This review provides a brief overview of recent advances in drug delivery systems based on aptamers. The advantages, challenges and future prospectives are also discussed.

scholarly journals Spectropolarimetry of stripped-envelope supernovae: observations and modelling

2017 ◽  
Vol 375 (2105) ◽  
pp. 20160273 ◽  
Author(s):  
Masaomi Tanaka
Keyword(s):  
Large Scale ◽  
Massive Stars ◽  
Three Dimensional ◽  
Core Collapse ◽  
Ion Distribution ◽  
Typical Size ◽  
Cassiopeia A ◽  
Accretion Shock

Spectropolarimetry is one of the most powerful methods to study the multi-dimensional geometry of supernovae (SNe). We present a brief summary of the spectropolarimetric observations of stripped-envelope core-collapse SNe. Observations indicate that stripped-envelope SNe generally have a non-axisymmetric ion distribution in the ejecta. Three-dimensional clumpy geometry nicely explains the observed properties. A typical size of the clumps deduced from observations is relatively large: 25% of the photosphere. Such a large-scale clumpy structure is similar to that observed in Cassiopeia A, and suggests that large-scale convection or standing accretion shock instability takes place at the onset of the explosion. This article is part of the themed issue ‘Bridging the gap: from massive stars to supernovae’.

scholarly journals Optical Coherence Tomography for Three-Dimensional Imaging in the Biomedical Field: A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Shu Zheng ◽  
Yanru Bai ◽  
Zihao Xu ◽  
Pengfei Liu ◽  
Guangjian Ni
Keyword(s):  
Optical Coherence Tomography ◽  
High Speed ◽  
Near Infrared ◽  
Polarization State ◽  
Three Dimensional ◽  
Biological Research ◽  
Light Sources ◽  
Optical Coherence ◽  
Biomedical Field

Optical coherence tomography (OCT) has become a novel approach to noninvasive imaging in the past three decades, bringing a significant potential to biological research and medical biopsy in situ, particularly in three-dimensional (3D) in vivo conditions. Specifically, OCT systems using broad bandwidth sources, mainly centered at near-infrared-II, allow significantly higher imaging depth, as well as maintain a high-resolution and better signal-to-noise ratio than the traditional microscope, which avoids the scattering blur and thus obtains more details from delicate biological structures not just limited to the surface. Furthermore, OCT systems combined the spectrometer with novel light sources, such as multiplexed superluminescent diodes or ultra-broadband supercontinuum laser sources, to obtain sub-micron resolution imaging with high-speed achieve widespread clinical applications. Besides improving OCT performance, the functional extensions of OCT with other designs and instrumentations, taking polarization state or birefringence into account, have further improved OCT properties and functions. We summarized the conventional principle of OCT systems, including time-domain OCT, Fourier-domain OCT, and several typical OCT extensions, compared their different components and properties, and analyzed factors that affect OCT performance. We also reviewed current applications of OCT in the biomedical field, especially in hearing science, discussed existing limitations and challenges, and looked forward to future development, which may provide a guideline for those with 3D in vivo imaging desires.

scholarly journals Robust 3D Hand Detection from a Single RGB-D Image in Unconstrained Environments

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6360
Author(s):  
Chi Xu ◽  
Jun Zhou ◽  
Wendi Cai ◽  
Yunkai Jiang ◽  
Yongbo Li ◽  
...  
Keyword(s):  
State Of The Art ◽  
Three Dimensional ◽  
Detection Accuracy ◽  
Light Conditions ◽  
Hand Detection ◽  
Lighting Conditions ◽  
Detection Approach ◽  
Dark Conditions ◽  
Bounding Boxes ◽  
Human Hands

Three-dimensional hand detection from a single RGB-D image is an important technology which supports many useful applications. Practically, it is challenging to robustly detect human hands in unconstrained environments because the RGB-D channels can be affected by many uncontrollable factors, such as light changes. To tackle this problem, we propose a 3D hand detection approach which improves the robustness and accuracy by adaptively fusing the complementary features extracted from the RGB-D channels. Using the fused RGB-D feature, the 2D bounding boxes of hands are detected first, and then the 3D locations along the z-axis are estimated through a cascaded network. Furthermore, we represent a challenging RGB-D hand detection dataset collected in unconstrained environments. Different from previous works which primarily rely on either the RGB or D channel, we adaptively fuse the RGB-D channels for hand detection. Specifically, evaluation results show that the D-channel is crucial for hand detection in unconstrained environments. Our RGB-D fusion-based approach significantly improves the hand detection accuracy from 69.1 to 74.1 comparing to one of the most state-of-the-art RGB-based hand detectors. The existing RGB- or D-based methods are unstable in unseen lighting conditions: in dark conditions, the accuracy of the RGB-based method significantly drops to 48.9, and in back-light conditions, the accuracy of the D-based method dramatically drops to 28.3. Compared with these methods, our RGB-D fusion based approach is much more robust without accuracy degrading, and our detection results are 62.5 and 65.9, respectively, in these two extreme lighting conditions for accuracy.

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