Quantification of Nanostructure Distribution in Tissue Using MicroCT Imaging

2011 ◽  
Author(s):  
Anilchandra Attaluri ◽  
Navid Manuchehrabadi ◽  
Anna Dechaumphai ◽  
Ronghui Ma ◽  
Liang Zhu
Keyword(s):  
Laser Energy ◽  
Three Dimensional ◽  
Laser Wavelength ◽  
Treatment Protocols ◽  
Geometric Ratio ◽  
Surrounding Healthy Tissue ◽  
Microct Imaging ◽  
Penetration Depths ◽  
Superficial Tissue ◽  
Tumor Area

Recently, two nanotechnologies have emerged as promising hyperthermia therapies due to their ability to confine adequate thermal energy in tumors. Both overcome the limitations of traditional hyperthermia approaches such as microwave and ultrasound, which have short penetration depths into tissue and often cause collateral thermal damage to the superficial tissue layers. One uses magnetic nanoparticles to generate heat when the nanoparticles are subject to an alternating magnetic field [1–2]. The other one uses gold nanoshells or nanorods in laser induced photothermal therapy [3–4]. By varying the geometric ratio, the nanostructures can be tuned to have strong absorption and scattering to a specific laser wavelength. The enhancement in laser energy absorption would confine the laser energy in a tumor area congregating by the nanostructure. The efficacy of these two methods relies on the achieved tumor temperature elevations which are largely determined by the nanostructure concentration distribution in the tumor. Therefore, having an imaging technique to directly visualize and analyze the three-dimensional nanostructure distribution in tumors would greatly improve treatment protocols to kill all tumor cells while avoiding overheating in the surrounding healthy tissue.

Thermal Effect of Gold Nanorods in Implanted Prostatic Tumors During Laser Photothermal Therapy

2012 ◽  
Author(s):  
N. Manuchehrabadi ◽  
L. Zhu ◽  
A. Attaluri ◽  
H. Cai ◽  
R. Edziah ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Systematic Approach ◽  
Thermal Damage ◽  
Tumor Tissue ◽  
Laser Energy ◽  
Laser Wavelength ◽  
Temperature Elevation ◽  
Treatment Protocols ◽  
Energy Absorbers

In recent years, nanotechnologies have emerged as promising therapies due to their ability to deliver adequate thermal dosage to irregular and/or deep-seated tumors. Gold nanorods can be tuned to a specific laser wavelength and serve as strong laser energy absorbers. Due to the powerful optical absorption, the laser energy is concentrated in an area congregating by nanorods, and then the energy absorbed can be transferred to the surrounding tumor tissue by heat conduction.1–4 Currently, there are wide variation ranges of treatment protocols using photothermal therapy. A systematic approach is lacking to analyze temperature elevation history in tumors during heating to design an optimized combination of laser parameters to maximize thermal damage to tumors.

Temperature Elevations in Implanted Prostatic Tumors During Laser Photothermal Therapy Using Nanorods

2011 ◽  
Author(s):  
L. Zhu ◽  
A. Attaluri ◽  
N. Manuchehrabadi ◽  
H. Cai ◽  
R. Edziah ◽  
...  
Keyword(s):  
Targeted Delivery ◽  
Photothermal Therapy ◽  
Near Infrared ◽  
Laser Energy ◽  
Laser Wavelength ◽  
Gold Nanoshells ◽  
Surrounding Tissue ◽  
Geometric Ratio ◽  
Wide Range ◽  
Laser Photothermal Therapy

Gold nanoshells or nanorods are newly developed nanotechnology in laser photothermal therapy for cancer treatments in recent years [1–10]. Gold nanoshells consists of a solid dielectric nanoparticle core (∼100 nm) coated by a thin gold shell (∼10 nm). Gold nanorods have a diameter of 10 nm and an aspect ratio of approximately four. Nanorods may be taken up by tumors more readily than nanoshells due to nanorods’ smaller size. By varying the geometric ratio, both nanoshells and nanorods can be tuned to have strong absorption and scattering to a specific laser wavelength. Among a wide range of laser wavelengths, the near infrared (NIR) laser at ∼800 nm is most attractive to clinicians due to its deep optical penetration in tissue. Therefore, the tissue would appear almost “transparent” to the 800 nm laser light before the laser reaches the nanoshells or nanorods in tumors, with minimal laser energy wasted by the tissue without the nanostructures. The laser energy absorbed in an area congregating by the nanostructures is transferred to the surrounding tissue by heat conduction. This approach not only achieves targeted delivery of laser energy to the tumor, but also maximally concentrates a majority of the laser energy to the tumor region.

Right Atrial Thrombosis and Pulmonary Embolism: A Narrative Review

2020 ◽  
Vol 46 (08) ◽  
pp. 895-907
Author(s):  
Nina D. Anfinogenova ◽  
Oksana Y. Vasiltseva ◽  
Alexander V. Vrublevsky ◽  
Irina N. Vorozhtsova ◽  
Sergey V. Popov ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Pulmonary Embolism ◽  
High Risk ◽  
Transesophageal Echocardiography ◽  
Three Dimensional ◽  
Right Atrial ◽  
Treatment Protocols ◽  
High Risk Patients ◽  
Risk Patients ◽  
The Right

AbstractPrompt diagnosis of pulmonary embolism (PE) remains challenging, which often results in a delayed or inappropriate treatment of this life-threatening condition. Mobile thrombus in the right cardiac chambers is a neglected cause of PE. It poses an immediate risk to life and is associated with an unfavorable outcome and high mortality. Thrombus residing in the right atrial appendage (RAA) is an underestimated cause of PE, especially in patients with atrial fibrillation. This article reviews achievements and challenges of detection and management of the right atrial thrombus with emphasis on RAA thrombus. The capabilities of transthoracic and transesophageal echocardiography and advantages of three-dimensional and two-dimensional echocardiography are reviewed. Strengths of cardiac magnetic resonance imaging (CMR), computed tomography, and cardiac ventriculography are summarized. We suggest that a targeted search for RAA thrombus is necessary in high-risk patients with PE and atrial fibrillation using transesophageal echocardiography and/or CMR when available independently on the duration of the disease. High-risk patients may also benefit from transthoracic echocardiography with right parasternal approach. The examination of high-risk patients should involve compression ultrasonography of lower extremity veins along with the above-mentioned technologies. Algorithms for RAA thrombus risk assessment and protocols aimed at identification of patients with RAA thrombosis, who will potentially benefit from treatment, are warranted. The development of treatment protocols specific for the diverse populations of patients with right cardiac thrombosis is important.

Three-dimensional depth profiling of prostate tissue by micro ATR-FTIR spectroscopic imaging with variable angles of incidence

The Analyst ◽  
2019 ◽  
Vol 144 (9) ◽  
pp. 2954-2964 ◽  
Author(s):  
Cai Li Song ◽  
Sergei G. Kazarian
Keyword(s):  
Three Dimensional ◽  
Depth Profiling ◽  
Spectroscopic Imaging ◽  
Prostate Tissue ◽  
Tissue Samples ◽  
Variable Angle ◽  
Penetration Depths

Variable angle micro ATR-FTIR, via the insertion of circular apertures, was used to measure tissue samples at various penetration depths.

Crystallization Studies of Glassy Te-Se-Br Thin Films

1989 ◽  
Vol 172 ◽  
Author(s):  
J. L. Adam ◽  
C. Ortiz ◽  
J. R. Salem ◽  
X. H. Zhang
Keyword(s):  
Thin Films ◽  
Heat Flow ◽  
Laser Power ◽  
Network Formation ◽  
Laser Energy ◽  
Pulse Length ◽  
Three Dimensional ◽  
Complete Loss ◽  
Fractal Network ◽  
Laser Pulse Length

AbstractWe have studied the effect of laser irradiation on Te-Se-Br thin films. The major effects were found to be dominated by changes in composition because of the complete loss of Br and variable loss of Se. These losses are measured by EIDS and are reasonable in view of the temperatures obtained from a heat flow calculation. The remaining Te-Se material can be made crystalline under specific conditions of laser pulse length and laser power (which determine the cooling rate). We have been able to establish that the crystallization starts with surface filamentary growth exhibiting fractal network formation. With higher laser energy it tends to coalesce to form three dimensional crystals.

scholarly journals Scanning electron microscope studies on laser ablation of solids

2019 ◽  
Vol 37 (01) ◽  
pp. 101-109 ◽  
Author(s):  
Mohamed E. Shaheen ◽  
Joel E. Gagnon ◽  
Brian J. Fryer
Keyword(s):  
Pulse Width ◽  
Laser Energy ◽  
Laser System ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Ablation Rate ◽  
Laser Wavelength ◽  
High Laser Fluence ◽  
Electron Imaging ◽  
Scanning Electron

AbstractThis study investigates the interaction of picosecond laser pulses with sapphire and brass in air using scanning electron microscopy. A picosecond laser system operating at a wavelength of 785 nm, pulse width of 110 ps, and variable repetition rate (1–1000 Hz) was used in this study. The pulse width applied in this work was not widely investigated as it lies in the gap between ultrashort (femtosecond) and long (nanosecond) pulse width lasers. Different surface morphologies were identified using secondary electron and backscattered electron imaging of the ablated material. Thermal ablation effects were more dominant in brass than in sapphire. Exfoliation and fractures of sapphire were observed at high laser fluence. Compared with brass, multiple laser pulses were necessary to initiate ablation in sapphire due to its poor absorption to the incident laser wavelength. Ablation rate of sapphire was lower than that of brass due to the dissipation of a portion of the laser energy due to heating and fracturing of the surface.

Regulation of fibroblast migration by tenascin-C

2007 ◽  
Vol 35 (4) ◽  
pp. 695-697 ◽  
Author(s):  
A. Trebaul ◽  
E.K. Chan ◽  
K.S. Midwood
Keyword(s):  
Tissue Repair ◽  
Tissue Injury ◽  
Three Dimensional ◽  
Scar Tissue ◽  
Fibrotic Disease ◽  
Tenascin C ◽  
Fibroblast Migration ◽  
Rate Limiting Step ◽  
Surrounding Healthy Tissue ◽  
Rate Limiting

Synthesis of new tissue by fibroblasts is required for tissue rebuilding in response to injury. Fibroblast migration from surrounding healthy tissue into the fibrin–fibronectin provisional matrix deposited upon injury is a key rate-limiting step of this stage of tissue repair. These events must be tightly regulated. Excessive deposition of scar tissue is the major hallmark of fibrotic disease. Tenascin-C is an extracellular matrix glycoprotein that is transiently expressed upon tissue injury, where it is specifically localized to the wound edge, and persistently up-regulated in fibrotic disease. We have shown that full-length tenascin-C promotes fibroblast migration within fibrin–fibronectin matrices and we have mapped the domains within the molecule critical for enhancing migration. We also demonstrated that specific fragments of tenascin-C inhibit fibroblast migration. These results suggest that transient expression of tenascin-C at the wound boundary is key to tissue repair: its induction recruits fibroblasts into the wound and fragments resulting from its breakdown prevent excessive fibroblast infiltration. Our results demonstrate how fibroblast migration in three-dimensional provisional matrices may be differentially regulated by proteolysis of matrix molecules and could explain how persistent expression of tenascin-C contributes to the progression of fibrotic disease.

Rapid Forming of Hydroxyapatite-Silica Ceramics

2010 ◽  
Vol 450 ◽  
pp. 137-140
Author(s):  
Fwu Hsing Liu ◽  
Tsui Yen Ni ◽  
Yung Kang Shen ◽  
Jeou Long Lee
Keyword(s):  
Porous Structure ◽  
Cross Section ◽  
3D Model ◽  
Treatment Process ◽  
Crystallization Process ◽  
Laser Energy ◽  
Raw Materials ◽  
Three Dimensional ◽  
Silica Matrix ◽  
Atomic Force

This paper proposes a solid freefrom fabrication (SFF) technology for fabricating hydroxyapatite(HA)-silica ceramics, which can generate porous three-dimensional physical objects. The HA powder and the silica are mixed with water into slurries form as raw materials. The slurries are paved by a scraper to from a thin layer which is selective scanned by a laser beam according to the cross-section of a 3D model. The HA particles are embeded in the sintered silica matrix to form green parts via a suitable range of process parameters. The benefits of this process are: bio-ceramic parts can be built by lower laser energy and faster fabricating speed. Following a subsequence heat treatment process has been developed to optimize the crystallization process and to increase the strength of the sintered parts. The parts were analyzed by an Atomic Force Microscope (AFM) to determine the surface roughness. The results obtained indicate that the proposed process was possible to generate multilayer, overhanging, and porous structure with brittle property but sufficient integrity for handling prior to post-processing. It was possible to produce the porous structure from the proposed hydroxyapatite-silica ceramics, which had a greater potential for possible bone scaffolds fabrication.

scholarly journals Experimental and Numerical Investigations of a Novel Laser Impact Liquid Flexible Microforming Process

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 599 ◽  
Author(s):  
Fei Liu ◽  
Huixia Liu ◽  
Chenkun Jiang ◽  
Youjuan Ma ◽  
Xiao Wang
Keyword(s):  
Numerical Simulation ◽  
Laser Energy ◽  
Pure Copper ◽  
Three Dimensional ◽  
Element Model ◽  
Force Transmission ◽  
Large Area ◽  
Laser Impact ◽  
Metallic Foils

A novel high strain rate microforming technique, laser impact liquid flexible embossing (LILFE), which uses laser induced shock waves as an energy source, and liquid as a force transmission medium, is proposed by this paper in order to emboss three-dimensional large area micro arrays on metallic foils and to overcome some of the defects of laser direct shock microembossing technology. The influences of laser energy and workpiece thickness on the deformation characteristics of the pure copper foils with the LILFE process were investigated through experiments and numerical simulation. A finite element model was built to further understand the typical stages of deformation, and the results of the numerical simulation are consistent with those achieved from the experiments. The experimental and simulation results show that the forming accuracy and depth of the embossed parts increases with the increase in laser energy and decrease in workpiece thickness. The thickness thinning rate of the embossed parts increases with the decrease of the workpiece thickness, and the severest thickness thinning occurs at the bar corner region. The experimental results also show that the LILFE process can protect the workpiece surface from being ablated and damaged, and can ensure the surface quality of the formed parts. Besides, the numerical simulation studies reveal the plastic strain distribution of embossed microfeatures under different laser energy.

Three-Dimensional Numerical Simulation and Experimental Study of Sheet Metal Bending by Laser Peen Forming

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Yongxiang Hu ◽  
Yefei Han ◽  
Zhenqiang Yao ◽  
Jun Hu
Keyword(s):  
Numerical Model ◽  
Sheet Metal ◽  
Laser Energy ◽  
Three Dimensional ◽  
Target Surface ◽  
Thick Sheet ◽  
Specimen Thickness ◽  
Forming Process ◽  
Form Complex ◽  
Peen Forming

Laser peen forming (LPF) is a purely mechanical forming method achieved through the use of laser energy to form complex shapes or to modify curvatures. It is flexible and independent of tool inaccuracies that result from wear and deflection. Its nonthermal process makes it possible to form without material degradation or even improve them by inducing compressive stress over the target surface. In the present study, a fully three-dimensional numerical model is developed to simulate the forming process of laser peen forming. The simulation procedure is composed of several steps mainly including the shock pressure prediction, the modal analysis, and the forming process calculation. System critical damping is introduced to prevent unnecessary long post-shock residual oscillations and to greatly decrease the solution time for simulation. The bending profiles and angles with different thicknesses are experimentally measured at different scanning lines and scanning velocities to understand the process and validate the numerical model. The calculated bending profiles and angles agree well with the trend of the measured results. But it is found that simulations with the Johnson–Cook model are more consistent, matching the experimental results for the thick sheet metal with a convex bending, while the elastic-perfectly-plastic model produces a better agreement even though with underestimated values for the thinner sheet metal with a concave bending. The reason for this phenomenon is discussed, combining the effects of strain rate and feature size. Both the simulation and the experiments show that a continuous decrease in bending angle from concave to convex is observed with increasing specimen thickness in general. Large bending distortion is easier to induce by generating a concave curvature with LPF, and the angle of bending distortion depends on the number of laser shocks.

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