Estimation of a minimum laser power with wavelengths of 1.47, 1.56, and 1.68 μm for efficient obliteration of varicose veins

2022 ◽  
Vol 52 (1) ◽  
pp. 78-82
Author(s):  
N Yu Ignat'eva ◽  
O L Zakharkina ◽  
A P Sviridov ◽  
K V Mazaishvili ◽  
A B Shekhter
Keyword(s):  
Absorption Coefficient ◽  
Varicose Veins ◽  
Laser Wavelength ◽  
Vasa Vasorum ◽  
Tissue Necrosis ◽  
Main Criterion ◽  
Calorimetric Analysis ◽  
Collagen Denaturation ◽  
The Relationship ◽  
Venous Wall

Abstract Experiments modelling endovenous laser obliteration (EVLO) are performed. As a result, laser radiation powers Pc at which collagen denaturation, tissue necrosis, and vasa vasorum destruction occur throughout the entire venous-wall thickness and, at the same time, the surrounding tissues are not subjected to unnecessary heating, are found. The main criterion for determining Pc is the achievement of 100% denaturation of venous-wall proteins, confirmed by morphological and calorimetric analysis. The Pc values for laser wavelengths of 1.47, 1.56, and 1.68 mm are found to be 6.0 ± 0.2, 5.0 ± 0.2, and 6.0 ± 0.2 W, respectively. It is established for all wavelengths in use that the temperature of the external venous-wall surface reaches 91 plusmn; 2 deg;C at the corresponding power Pc. We relate the dependence of Pc on the radiation wavelength to the formation of a coagulum on the optical fibre tip moving through a blood-filled vessel. The achievement of temperature necessary for coagulum formation is determined by the simultaneously occurring processes of energy absorption and its dissipation in the form of heat. These processes become more intense with an increase in the absorption coefficient of the medium. A mechanism is proposed to explain the relationship between the Pc value and laser wavelength, based on the influence of the absorption coefficient of medium (blood) on the temperature near the fibre tip.

Linear and Nonlinear Optical Properties of Natural Dyes Freestanding Films and Application in Optical Limiting

2020 ◽  
pp. 139-143
Keyword(s):  
Absorption Coefficient ◽  
Water Solution ◽  
Optical Limiting ◽  
Refraction Index ◽  
Laser Wavelength ◽  
Solid State Laser ◽  
Natural Dyes ◽  
Linear And Nonlinear ◽  
532 Nm ◽  
Absorbance Spectra

Natural dyes were followed and prepared from a pomegranate, purple carrot, and eggplant peel. The absorbance spectra was measured in the wavelength range 300-800 nm. The linear properties measurements of the prepared natural dye freestanding films were determined include absorption coefficient (α0), extinction coefficient (κ), and linear refraction index (n). The nonlinear refractive index n2 and nonlinear absorption coefficient β2 of the natural dyes in the water solution were measured by the optical z-scan technique under a pumped solid state laser at a laser wavelength of 532 nm. The results indicated that the pomegranate dye can be promising candidates for optical limiting applications with significantly low optical limiting of 3.5 mW.

SIGNIFICANT ASPECTS OF EPIDEMIOLOGY, RISK FACTORS AND TREATMENT OF VARICOSE VEINS

2020 ◽  
pp. 320-328
Author(s):  
O.F. SOLIEV ◽  
◽  
D.D. SULTANOV ◽  
S.P. KURBANO ◽  
N.R. KURBANOV ◽  
...  
Keyword(s):  
Risk Factors ◽  
Optical Fibers ◽  
High Efficiency ◽  
Varicose Veins ◽  
Laser Wavelength ◽  
Comprehensive Treatment ◽  
Literature Analysis ◽  
Pregnancy And Childbirth ◽  
Laser Ablation Technique ◽  
Significant Factors

The literature review focuses on the significant aspects of epidemiology, analysis of risk factors and modern principles of surgical treatment of varicose veins. Literature data show that considering pathology in recent years has a tendency to increase the frequency and the significant factors at risk of its development are the inheritance, overweight, as also pregnancy and childbirth of two or more. In recent years, new thermal catheter techniques have become more frequent in the treatment of varicose veins, which demonstrate their advantages and high efficiency. The literature analysis shows that the use of a 1470 nm laser wavelength with a radial type of optical fibers has the highest coagulating effect compared to other types of laser. The authors of the article provided detailed coverage of the endovascular laser ablation technique, showing its advantages over other methods, and its role and place in the comprehensive treatment of the varicose veins.

Modeling of CO2 Gas Excitation Under CO2 Laser Irradiation

2006 ◽  
Author(s):  
Lan Jiang ◽  
Hai-Lung Tsai
Keyword(s):  
Absorption Coefficient ◽  
Co2 Laser ◽  
Population Distribution ◽  
Boltzmann Distribution ◽  
Laser Wavelength ◽  
Equilibrium States ◽  
Published Data ◽  
Co2 Absorption ◽  
Co2 Gas ◽  
Laser Coating

Lasers especially multiple laser beams demonstrate unique advantages as energy sources in diamond synthesis. However, the fundamental mechanisms involved in the laser-assisted processes are not Well understood. In a reported amazingly-fast multiple laser coating technique, CO2 gas is claimed as the sole precursor or secondary precursor, which remains poorly understood and unverified. The absorption coefficient changes under the irradiation of the multiple lasers are one of the keys to resolve the mysteries of multiple laser beam coating processes. This study investigates the optical absorption in CO2 gas at the CO2 laser wavelength. This resonance absorption process is modeled as an inverse process of the lasing transitions of CO2 lasers. The well-established CO2 vibrational-rotational energy structures are used as the basis for the calculations with the Boltzmann distribution for equilibrium states and the three-temperature model for non-equilibrium states. Based on the population distribution, our predictions of CO2 absorption coefficient changes as the function of temperature are in agreement with the published data.

Information Content of AVHRR Channels 4 and 5 with Respect to the Effective Radius of Cirrus Cloud Particles

1991 ◽  
Vol 30 (7) ◽  
pp. 973-984 ◽  
Author(s):  
F. Parol ◽  
J. C. Buriez ◽  
G. Brogniez ◽  
Y. Fouquart
Keyword(s):  
Absorption Coefficient ◽  
Mean Value ◽  
Effective Radius ◽  
Forward Peak ◽  
Effective Absorption Coefficient ◽  
Brightness Temperatures ◽  
Microphysical Properties ◽  
Effective Absorption ◽  
Cloud Particles ◽  
The Relationship

Abstract This paper investigates the important difference in the relationship between brightness temperatures between the 11-μm and the 12-μn AVHRR data and the microphysical properties of the semitransparent cirrus clouds. In the nonscattering approximation, the emittance for channels 4 and 5 are related through the absorption coefficient ratio that is the key parameter giving access to the size of cloud particles. The observed mean value of this parameter corresponds to effective radius of 18 μm for polydisperse spheres and 12 μm for polydisperse infinitely long ice cylinders. Taking the multiple scattering into account, the brightness temperature difference enhances much more for cylinders than for spheres owing to the fact that the forward peak of scattering is less large for cylinders. To obtain the size of cloud particles, the method developed in the nonscattering case is still applicable if one makes use of the effective emittance that implicitly includes the effects of mattering. Thus, an effective absorption coefficient ratio is defined and we derive a direct relationship between this ratio and the optical properties of the cloud particles. The mean value of the effective absorption coefficient ratio corresponds to ice spheres of effective radius of 26 μm or a bit less in the case of water spheres (supercooled droplets), but no agreement can be obtained for fully randomly oriented cylinders.

scholarly journals MORPHOLOGICAL PARALLELS OF THE STRUCTURE OF VESSEL’S WALL AT VARICOSE EXTENSION OF THE VEINS OF PELVIS AND LOWER EXTREMITIES

2020 ◽  
Vol 28 (2) ◽  
pp. 24-31
Author(s):  
Rustem V. Akhmetzianov ◽  
Roman A. Bredikhin ◽  
Elena E. Fomina ◽  
Elena F. Konovalova
Keyword(s):  
Structural Changes ◽  
Varicose Veins ◽  
High Body Mass Index ◽  
Lower Extremities ◽  
Vascular Lesions ◽  
Wall Structure ◽  
Ovarian Vein ◽  
Saphenous Veins ◽  
Risk Predictors ◽  
Venous Wall

The histological differences in the structure of the ovarian vein and saphenous veins of the lower extremities during their varicose transformation have been insufficiently studied in the modern literature. The study aims to determine the morphological parallels of the structure of varicose veins in varicose veins of the pelvis and varicose veins of the lower extremities. Fifty histological biopsy specimens of removed veins were examined in women. Of these, 25 large saphenous veins were obtained from patients with varicose veins of the lower extremities and 25 preparations of a resected ovarian vein from 25 women with varicose veins of the pelvis. The preparation was stained with hematoxylin-eosin and by the Van Gieson method, studied by light microscopy. In the study of the preparations, significant structural changes were noted in all layers of the venous wall, both in varicose veins of the pelvis and in varicose veins of the lower extremities in the form of a combination of atrophic, fibroplastic and hypertrophic processes leading to the loss of its functional properties. Depending on the decompensation of pathological processes, 3 morphological forms of lesions of the venous wall structure were revealed. The hypertrophic form was found in 17 (34%) surgery perform women, fibrous - in 13 (26%), atrophic - in 20 (40%). In the group of patients with varicose veins of the pelvis compared with the group of patients with varicose veins of the lower extremities, the prevalence of initial forms of lesion was revealed. There was a correlation between the severity of venous vascular lesions with the duration of the disease and the patient's age, the number of risk predictors and a high body mass index, which was the determining factor in the occurrence of this phenomenon. The results of this study indicate the similarity of the pathological picture of venous lesions, both in varicose veins of the pelvis and in varicose veins of the lower extremities.

scholarly journals Kønsligt hierarki eller religiøs androgyni

2000 ◽  
Author(s):  
Birgitte Graakjær Hjort
Keyword(s):  
New Testament ◽  
Broad Sense ◽  
Main Criterion ◽  
Men And Women ◽  
Religious Ritual ◽  
The New Testament ◽  
The Creation ◽  
The Relationship ◽  
Ritual Context ◽  
Specific Influence

Only a few texts from the New Testament have been used and misused as have 1 Cor 11:2-16. A widespread misreading of the pericope consists in the interpretation that Paul there argued against equality between men and women generally or in the context of worship. The purpose of this article is twofold: To demonstrate why this reading is untenable and to argue for a more proper interpretation.My reading is based on Paul’s line of argument, including his remarkable formation of the kephale-structure and the position of the pericope between chapters (8 and) 10 and 11:17-21, respectively, as well as on the letter as a whole. All these things together indicate that the problem under discussion was not the relationship between the sexes as such, but this relationship seen in a religious, ritual context. Paul reproved a conduct whose shamefulness lay in its threat to both the gender polarity according to the creation and the sovereignty of God, a conduct which may also have caused divisions in the community. What Paul was arguing against, was a syncretism whose hallmark was an emancipatory equalization of gender polarity and, maybe, ritual intoxication and whose religious precedent was to be found in the worshipping of idols.With this interpretation as the main criterion for testing different hypotheses put forward to explain the historical situation causing Paul to write the text, I have found that a possible reconstruction consists of an influence on the Corinthians from pre-gnostic thoughts in a broad sense, combined with a more specific influence from the cult of Dionysus.

scholarly journals Features of the Cognitive Component "Self-Concept" Structure in Middle-Aged Women with Different Stages of Varicose Veins

2020 ◽  
Keyword(s):  
Varicose Veins ◽  
Structural Features ◽  
Middle Aged ◽  
Stages Of Development ◽  
Behavioral Reactions ◽  
Cognitive Component ◽  
Second Stage ◽  
Psychological Science ◽  
Stage Of Development ◽  
The Relationship

The article is devoted to the study of the structural features of the cognitive component of the "I-concept" in middle-aged women. They are at different stages of development of varicose veins. The cognitive component of the “I-concept” is a significant prerequisite for the manifestation of potential behavioral reactions. In modern psychological science, the most studied are aspects related to the psychosomatic manifestation of varicose veins, issues related to the psychological causes of varicose veins and the effect of the disease on the human psyche. At the same time, the question of how the level of development of varicose veins manifests itself in the features of the "I-concept" (in particular, its cognitive component) remains insufficiently studied. The study involved 50 women (35-40 years old) with varying degrees of development of varicose veins. The first group included 25 women with varicose veins of the first stage (no surgical intervention is required). The second group consisted of 25 women with the second stage of the disease (with surgery). According to the survey, the main causes of the disease were quite different. This is a sports load, a criterion for heredity, diseases during pregnancy, etc. There were revealed certain similarities and differences in the manifestations of the cognitive component of the "I-concept" of the personality of these women, depending on the stage of development of varicose veins. General factors were determined that describe the nature of the relationship between the elements of the cognitive component "I-concept" and a certain stage of varicose veins in middle-aged women. Individual psychological characteristics of the personality play a major role in the manifestation of types of self-attitude in middle-aged women with different stages of development of varicose veins. The nature of the relationship between the types of attitudes, self-attitudes towards the disease, the degrees of clarity of the "I‑concept" is different. A more complex and diverse nature of the relationship is inherent in a group of women with a medication type of treatment.

scholarly journals Biological safety of Electroacupuncture with STS316 needles

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Kwang-Ho Choi ◽  
Sun Hee Yeon ◽  
Seong Jin Cho ◽  
O Sang Kwon ◽  
Sanghun Lee ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Critical Point ◽  
Analgesic Effect ◽  
Maximum Intensity ◽  
Clinical Settings ◽  
Cell Necrosis ◽  
Tissue Necrosis ◽  
Time Frequency ◽  
Critical Range ◽  
The Relationship

Abstract Background Electroacupuncture (EA) is often used in clinical settings due to its analgesic effect, but its safety has not been verified due to the lack of clear criteria. This study examined the critical range of the corrosion of stainless steel types STS304 and STS316, which have been used clinically, and the relationship between needle corrosion and cell necrosis. Method The critical point of corrosion for STS304 and STS316 was identified by varying the time, frequency, and stimulation intensity. In a tissue necrosis experiment, EA stimulation was applied to rats using STS316 needles with different thicknesses at maximum intensity for 60 min, and the presence of corrosion and tissue necrosis was determined. A cytotoxicity experiment was also conducted and assessed the needles and tissue necrosis. Results The results showed that STS316 was more stable than STS304 and that only coated needles corroded. Furthermore, tissue necrosis was observed regardless of corrosion, and slight cell necrosis was associated with needles with corrosion. Conclusions This study demonstrated that non-coated STS316 was the most stable for EA stimulation and that corrosion byproducts and cell necrosis were not directly related.

Optical Effects of Large Particles

Ocean Optics ◽  
1994 ◽  
Author(s):  
Kendall L. Carder ◽  
David K. Costello
Keyword(s):  
Optical Properties ◽  
Absorption Coefficient ◽  
Process Model ◽  
Light Field ◽  
Ocean Optics ◽  
Backscattering Coefficient ◽  
Model Inversion ◽  
Inherent Optical Properties ◽  
And Inversion ◽  
The Relationship

Two important problems facing the ocean optics research community in the coming decade concern optical model closure and inversion (see Chapter 3). We obtain model closure if we can describe the measured light environment by combining elementary measurements of the optical properties of the medium with radiative transfer theory. If we can accurately deduce the concentration of various constituents from a combination of measures of the submarine light field and inverse model calculations, we term this process model inversion. The most elementary measurements of the optical properties of the sea are those that are independent of the geometry of the light field, the inherent optical properties (Preisendorfer, 1961). Optical properties that are dependent on the geometry of the light field are termed apparent optical properties (AOP). Models of the submarine light field typically relate apparent optical properties to inherent optical properties (see Chapter 2). Examples include the relationship between the AOP irradiance reflectance R and a combination of inherent optical properties (backscattering coefficient bb and absorption coefficient a), and the relationship between the AOP downwelling diffuse attenuation coefficient kd and a combination of the absorption coefficient, backscattering coefficient, and downwelling average cosine μd (e.g., Gordon et al., 1975; Morel and Prieur, 1977; Smith and Baker, 1981; Morel, 1988; Kirk, 1984a). Under some circumstances these relationships work well enough that the absorption coefficient can be derived indirectly. This is important since measurement of the absorption coefficient by direct means has been difficult. Derived values for the absorption coefficient by model inversion methods are not easily verified by independent measurements, however, because of the difficulty of measuring the absorption coefficient. Model closure and model inversion both become more tenuous when the following phenomena are present: 1. Transpectral or inelastic scattering such as fluorescence (e.g., Gordon, 1979; Carder and Steward, 1985; Mitchell and Kiefer, 1988a; Spitzer and Dirks, 1985; Hawes and Carder, 1990) or water Raman scattering (Marshall and Smith, 1990; Stavn, 1990; Stavn and Weidemann, 1988a,b; Peacock et al, 1990; Chapter 12 this volume). 2. Particles that are large relative to the measurement volume for inherent optical property meters such as beam transmissometers, light-scattering photometers, fluorometers, and absorption meters.

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