scholarly journals Ex-Vivo Exposure on Biological Tissues in the 2-μm Spectral Range with an All-Fiber Continuous-Wave Holmium Laser

Photonics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 20
Author(s):  
Mariya S. Kopyeva ◽  
Serafima A. Filatova ◽  
Vladimir A. Kamynin ◽  
Anton I. Trikshev ◽  
Elizaveta I. Kozlikina ◽  
...  
Keyword(s):  
Solid State ◽  
Soft Tissues ◽  
Continuous Wave ◽  
Ex Vivo ◽  
Laser System ◽  
Biological Tissues ◽  
Holmium Laser ◽  
Experimental Point ◽  
Ablation Efficiency ◽  
Wide Range

We present the results on the interaction of an all-fiber Holmium-doped laser CW radiation at a wavelength of 2100 nm with soft tissues and compare it with the other results obtained by the most used solid-state laser systems. Ex-vivo single spot experiments were carried out on the porcine longissimus muscles by varying the laser impact parameters in a wide range (average output power 0.3, 0.5 and 1.1 W; exposure time 5, 30 and 60 s). Evaluation of the laser radiation exposure was carried out by the size of coagulation and ablation zones on the morphological study. Exposure to a power of 0.3 W (1.5–18 J of applied energy) caused only reversible changes in the tissues. The highest applied energy of 66 J for 1.1 W and a 60-s exposure resulted in a maximum ablation depth of approximately 1.2 mm, with an ablation efficiency of 35%. We have shown that it is not necessary to use high powers of CW radiation, such as 5–10 W in the solid-state systems to provide the destructive effects. Similar results can be achieved at lower powers using the simple all-fiber Holmium laser based on the standard single-mode fiber, which could provide higher power densities and be more convenient to manufacture and use. The obtained results may be valuable as an additional experimental point in the field of existing results, which in the future will allow one to create a simple optimal laser system for medical purposes.

scholarly journals Constitutive modelling of arteries

2010 ◽  
Vol 466 (2118) ◽  
pp. 1551-1597 ◽  
Author(s):  
Gerhard A. Holzapfel ◽  
Ray W. Ogden
Keyword(s):  
Mechanical Behaviour ◽  
Soft Tissues ◽  
Elastic Strain Energy ◽  
Cylindrical Tube ◽  
Strain Energy Function ◽  
Biological Tissues ◽  
Constitutive Modelling ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Modelling Effort

This review article is concerned with the mathematical modelling of the mechanical properties of the soft biological tissues that constitute the walls of arteries. Many important aspects of the mechanical behaviour of arterial tissue can be treated on the basis of elasticity theory, and the focus of the article is therefore on the constitutive modelling of the anisotropic and highly nonlinear elastic properties of the artery wall. The discussion focuses primarily on developments over the last decade based on the theory of deformation invariants, in particular invariants that in part capture structural aspects of the tissue, specifically the orientation of collagen fibres, the dispersion in the orientation, and the associated anisotropy of the material properties. The main features of the relevant theory are summarized briefly and particular forms of the elastic strain-energy function are discussed and then applied to an artery considered as a thick-walled circular cylindrical tube in order to illustrate its extension–inflation behaviour. The wide range of applications of the constitutive modelling framework to artery walls in both health and disease and to the other fibrous soft tissues is discussed in detail. Since the main modelling effort in the literature has been on the passive response of arteries, this is also the concern of the major part of this article. A section is nevertheless devoted to reviewing the limited literature within the continuum mechanics framework on the active response of artery walls, i.e. the mechanical behaviour associated with the activation of smooth muscle, a very important but also very challenging topic that requires substantial further development. A final section provides a brief summary of the current state of arterial wall mechanical modelling and points to key areas that need further modelling effort in order to improve understanding of the biomechanics and mechanobiology of arteries and other soft tissues, from the molecular, to the cellular, tissue and organ levels.

A Ternary Solution for Independent Acoustic Impedance and Speed of Sound Matching to Biological Tissues

1982 ◽  
Vol 4 (2) ◽  
pp. 163-170 ◽  
Author(s):  
Jonathan Ophir ◽  
Paul Jaeger
Keyword(s):  
Speed Of Sound ◽  
Acoustic Impedance ◽  
Soft Tissues ◽  
Sound Propagation ◽  
Biological Tissues ◽  
Liquid System ◽  
The Body ◽  
Acoustic Parameters ◽  
Wide Range

In applications requiring a liquid which is acoustically well matched to biological tissues, it is often difficult to find a material which is matched well in terms of both the acoustic impedance and speed of sound propagation in it; changing one parameter invariably affects the other. A three component liquid system is described, which allows independent adjustment of these two acoustic parameters over a wide range. This range encompasses the soft tissues of the body. Results of parameter measurements are presented in the form which allows simple determination of the mixture required to match any combination of acoustic impedance and speed of sound propagation over a given range.

scholarly journals Novel Ex Vivo Zymography Approach for Assessment of Protease Activity in Tissues with Activatable Antibodies

Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1390
Author(s):  
Bruce Howng ◽  
Michael B. Winter ◽  
Carol LePage ◽  
Irina Popova ◽  
Michael Krimm ◽  
...  
Keyword(s):  
Protease Activity ◽  
Ex Vivo ◽  
Human Tumor ◽  
Cancer Therapeutics ◽  
Biological Tissues ◽  
Clinical Samples ◽  
Reliable Technique ◽  
Physiological Processes ◽  
Wide Range ◽  
Therapeutic Development

Proteases are involved in the control of numerous physiological processes, and their dysregulation has been identified in a wide range of pathologies, including cancer. Protease activity is normally tightly regulated post-translationally and therefore cannot be accurately estimated based on mRNA or protein expression alone. While several types of zymography approaches to estimate protease activity exist, there remains a need for a robust and reliable technique to measure protease activity in biological tissues. We present a novel quantitative ex vivo zymography (QZ) technology based on Probody® therapeutics (Pb-Tx), a novel class of protease-activated cancer therapeutics that contain a substrate linker cleavable by tumor-associated proteases. This approach enables the measurement and comparison of protease activity in biological tissues via the detection of Pb-Tx activation. By exploiting substrate specificity and selectivity, cataloguing and differentiating protease activities is possible, with further refinement achieved using protease-specific inhibitors. Using the QZ assay and human tumor xenografts, patient tumor tissues, and patient plasma, we characterized protease activity in preclinical and clinical samples. The QZ assay offers the potential to increase our understanding of protease activity in tissues and inform diagnostic and therapeutic development for diseases, such as cancer, that are characterized by dysregulated proteolysis.

scholarly journals Contrast-Enhanced MicroCT for Virtual 3D Anatomical Pathology of Biological Tissues: A Literature Review

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Sébastien de Bournonville ◽  
Sarah Vangrunderbeeck ◽  
Greet Kerckhofs
Keyword(s):  
Soft Tissues ◽  
Ex Vivo ◽  
Functional Characterization ◽  
3D Structure ◽  
Biological Tissues ◽  
X Ray ◽  
Musculoskeletal Tissues ◽  
Contrast Enhanced ◽  
Anatomical Pathology

To date, the combination of histological sectioning, staining, and microscopic assessment of the 2D sections is still the golden standard for structural and compositional analysis of biological tissues. X-ray microfocus computed tomography (microCT) is an emerging 3D imaging technique with high potential for 3D structural analysis of biological tissues with a complex and heterogeneous 3D structure, such as the trabecular bone. However, its use has been mostly limited to mineralized tissues because of the inherently low X-ray absorption of soft tissues. To achieve sufficient X-ray attenuation, chemical compounds containing high atomic number elements that bind to soft tissues have been recently adopted as contrast agents (CAs) for contrast-enhanced microCT (CE-CT); this novel technique is very promising for quantitative “virtual” 3D anatomical pathology of both mineralized and soft biological tissues. In this paper, we provided a review of the advances in CE-CT since the very first reports on the technology to date. Perfusion CAs for in vivo imaging have not been discussed, as the focus of this review was on CAs that bind to the tissue of interest and that are, thus, used for ex vivo imaging of biological tissues. As CE-CT has mostly been applied for the characterization of musculoskeletal tissues, we have put specific emphasis on these tissues. Advantages and limitations of multiple CAs for different musculoskeletal tissues have been highlighted, and their reproducibility has been discussed. Additionally, the advantages of the “full” 3D CE-CT information have been pinpointed, and its importance for more detailed structural, spatial, and functional characterization of the tissues of interest has been shown. Finally, the remaining challenges that are still hampering a broader adoption of CE-CT have been highlighted, and suggestions have been made to move the field of CE-CT imaging one step further towards a standard accepted tool for quantitative virtual 3D anatomical pathology.

scholarly journals High power continuous-wave 1064 nm DPSS laser for machining semiconductor and metal materials

2013 ◽  
Vol 16 (1) ◽  
pp. 37-47
Author(s):  
Khoa Thanh Nhat Phan ◽  
Chien Mau Dang
Keyword(s):  
Solid State ◽  
Pump Power ◽  
Active Medium ◽  
High Power ◽  
Slope Efficiency ◽  
Continuous Wave ◽  
Laser System ◽  
Anisotropic Crystal ◽  
Diode Pumped ◽  
Metal Materials

A diode-pumped solid-state (DPSSL) laser system with 808 nm laser as pump source has been developed successfully. We used the optically anisotropic crystal Nd:YVO4 as the active medium. The threshold pump power and slope efficiency were measured and discussed. With lowly doped crystal Nd:YVO4 0.27% and concave-plane cavity, the laser showed good performance in the pumping range up to 11 W. Using the 1064 nm beam, micromachining were successfully conducted upon some normal materials such as plastic, wood; some semiconductors such as silicon and metals such as aluminum, copper, steel.

Performance of gain-switched all-solid-state quasi-continuous-wave tunable Ti:sapphire laser system

2008 ◽  
Vol 17 (10) ◽  
pp. 3759-3764 ◽  
Author(s):  
Ding Xin ◽  
Zhang Heng ◽  
Wang Rui ◽  
Yu Xuan-Yi ◽  
Wen Wu-Qi ◽  
...  
Keyword(s):  
Solid State ◽  
Continuous Wave ◽  
Laser System ◽  
Ti:Sapphire Laser

scholarly journals Identifying a Minimal Rheological Configuration: A Tool for Effective and Efficient Constitutive Modeling of Soft Tissues

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Petr Jordan ◽  
Amy E. Kerdok ◽  
Robert D. Howe ◽  
Simona Socrate
Keyword(s):  
Soft Tissues ◽  
Ex Vivo ◽  
Constant Strain Rate ◽  
Structural Response ◽  
Biological Tissues ◽  
Tissue Response ◽  
Model Parameters ◽  
Modeling Framework ◽  
Porcine Liver ◽  
Constitutive Relationships

We describe a modeling methodology intended as a preliminary step in the identification of appropriate constitutive frameworks for the time-dependent response of biological tissues. The modeling approach comprises a customizable rheological network of viscous and elastic elements governed by user-defined 1D constitutive relationships. The model parameters are identified by iterative nonlinear optimization, minimizing the error between experimental and model-predicted structural (load-displacement) tissue response under a specific mode of deformation. We demonstrate the use of this methodology by determining the minimal rheological arrangement, constitutive relationships, and model parameters for the structural response of various soft tissues, including ex vivo perfused porcine liver in indentation, ex vivo porcine brain cortical tissue in indentation, and ex vivo human cervical tissue in unconfined compression. Our results indicate that the identified rheological configurations provide good agreement with experimental data, including multiple constant strain rate load/unload tests and stress relaxation tests. Our experience suggests that the described modeling framework is an efficient tool for exploring a wide array of constitutive relationships and rheological arrangements, which can subsequently serve as a basis for 3D constitutive model development and finite-element implementations. The proposed approach can also be employed as a self-contained tool to obtain simplified 1D phenomenological models of the structural response of biological tissue to single-axis manipulations for applications in haptic technologies.

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