Selective Energy Absorption Research Articles

MEASUREMENTS AGAINST NOISE BACKGROUND AND WITH FLUCTUATIONS

When performing non-contact and remote measurements of various parameters, additional obstacles arise due to the influence of the intermediate medium and the measuring path between different links of the measuring system. These obstacles include:
 
 Noises arising in communication paths, intermediate media, complexes of measuring and auxiliary equipment. These noises are superimposed on the useful signal and distort it.
 Fluctuations of the general and selective energy absorption of the useful signal in the intermediate medium and measuring communication path. In all these cases, it is necessary to isolate the useful signal and restore its original true value and nature of non-stationarity.
 
 The task of filtering in its general form has not been completely solved until now. In order to obtain maximum information about the useful signal, such an operator L is selected that the function Y(τ)=L[X(τ)] slightly differs from the useful signal U(τ), where X(τ)= U(τ)+ V(τ ); V(τ) is noise (interference). To determine the values of the function Y(τ) at a certain time τ_0, all previous values of the function X(τ) from the interval -∞≤τ≤τ_0 should be used. To distinguish the functions Y(τ) and U(τ) the variance of the difference of these functions is used. The problem of Wiener filtering has been solved by various authors, in particular the Kalman-Busy filter equation for linear Gaussian systems. Optimal (suboptimal) Bayesian filters are constructed for a nonlinear stochastic system disturbed by "white" Gaussian noise with continuous time and discrete measurements that minimizes the root-mean-square error of estimation. The exact solution of this problem in the interval between the moments of measurement results is subject to the Fokker-Planck differential equation with private derivatives.
 Considered examples: measuring the temperature and pressure of the environment under investigation, distorted by various random factors in the form of "white" noise, as well as tracking the coordinates and velocities of an aircraft performing a maneuver in the horizontal plane - as test tasks in the construction of a sigma-point Kalman filter - as a multi-cube Kalman filter.

Modulated Electrohyperthermia: A New Hope for Cancer Patients.

According to the World Health Organization, the prevalence of cancer has increased worldwide. Oncological hyperthermia is a group of methods that overheat the malignant tissues locally or systematically. Nevertheless, hyperthermia is not widely accepted, primarily because of the lack of selectivity for cancer cells and because the temperature-triggered higher blood flow increases the nutrient supply to the tumor, raising the risk of metastases. These problems with classical hyperthermia led to the development of modulated electrohyperthermia (mEHT). The biophysical differences of the cancer cells and their healthy hosts allow for selective energy absorption on the membrane rafts of the plasma membrane of the tumor cells, triggering immunogenic cell death. Currently, this method is used in only 34 countries. The effectiveness of conventional oncotherapies increases when it is applied in combination with mEHT. In silico, in vitro, and in vivo preclinical research studies have all shown the extraordinary ability of mEHT to kill malignant cells. Clinical applications have improved the quality of life and the survival of patients. For these reasons, many other research studies are presently in progress worldwide. Thus, the objective of this review is to highlight the capabilities and advantages of mEHT and provide new hopes for cancer patients worldwide.

Nanoheating without Artificial Nanoparticles

Our aim is to describe the physical and physiological effects of local modulated electro-hyperthermia (mEHT). The method concentrates on the energy absorption of cluster rafts of the plasma membrane. The targeted cluster contains transmembrane proteins, which can form coherent working voltage-gated ion channels and/or TRP receptors in one domain. This targeting is analogous to nanoparticle heating, except this uses readily available nanoparticles on the cell membrane instead of the artificially placed nano-object to induce selective energy absorption from the outside field. In the discussed non-artificial nanoparticle heating, selectivity is the consequence of the synergy of various interactions embedded into each other in their effective volume in macro-, micro- and nano-ranges.

Selective Laser Trabeculoplasty: A Clinical Review.

ABSTRACTSelective laser trabeculoplasty (SLT) is a safe and effective treatment modality for lowering the intraocular pressure in patients with glaucoma. It achieves its results by selective absorption of energy in the trabecular pigmented cells, sparing adjacent cells and tissues from thermal damage, with minimal morphological tissue alteration following treatment. On the basis of the peer-reviewed medical literature, SLT is efficacious in lowering IOP, as initial treatment or when medical therapy is insufficient in all types of open-angle glaucoma in all races. SLT achieves intraocular pressure reduction similar to that of argon laser trabeculoplasty but without the tissue destruction and side effects. Observed side effects following SLT were almost uniformly transient and minor. We review highlights of recently published studies on the mechanisms and clinical outcome of SLT in order to address frequently raised issues pertinent to SLT in the clinical practice.Key messages: Selective laser trabeculoplasty is a safe and effective treatment modality for lowering the intraocular pressure in patients with glaucoma.How to cite this article: Alon S. Selective Laser Trabeculoplasty: A Clinical Review. J Current Glau Prac 2013; 7(2):58-65.

Enhancement of chromosomal aberrations in tumor cells with a non-labeled Cu–PTSM and irradiation with Cu K-shell monochromatic X rays

This study aims to clarify the enhancement effect on chromosomal aberrations via selective energy absorption by Cu atoms in cultured bone cancer cells with non-labelled Cu-pyruvaldehyde-bis(N(4)-methylsemicarbazone) (Cu-PTSM) and monochromatic X rays. The X rays having the energy of the Cu K-shell absorption edge arising from synchrotron radiation (KEK-PF) was used as radiation source. Cu-PTSM labelled with copper radionuclides has been developed for medical imaging using positron emission tomography (PET). Evidence clearly showed that the absorption of X rays in the Cu K-shell caused this enhancement. After cells were treated with 1000 nM Cu-PTSM, the enhancement ratio of the initial yield of isochromatid breaks caused by CuK-H X-ray irradiation to that by 200 kV(p) X rays was approximately 2.8. About 5.6 times of the remaining isochromatid breaks were observed at 4 h in Cu-PTSM treated samples irradiated with CuK-H X rays comparing to that with 200 kV(p) X rays. In this study, uniqueness in physical property such as Cu atom K-shell ionisation was applied for the enhancement of biological effects in cancer cells.

Shaking-induced cooling of cold atoms in a magnetic trap

By shaking a magnetic trap spatially, trapped cold Rb atoms are either heated or further cooled, depending on the shaking frequency. The atom temperature as a function of shaking frequency exhibits a dispersion-shaped resonance, which is caused by frequency selective energy absorption due to the anharmonicity of the trap potential. Selective heating of high-energy atoms enhances their loss, which can result in cooling rather than heating of a trapped atomic cloud.

The curing of powder coatings using gaseous infrared heaters: An analytical model to assess the process thermal efficiency

This experimental investigation is structured to determine the efficiency of energy transfer between a gaseous infrared burner and a powder coated surface being cured. The results from the experimental burner tests are interpreted using a Monte Carlo based numerical simulation. This simulation incorporates both an Edwards' exponential wide band model for the spectrally selective energy absorption and emission in the flue gas, and test measurements for the powders' spectral absorption characteristics. The results from the simulation show that efficiency of the energy transfer from the natural gas stream to the powdered surface ranges between 25 % and 30 %, when the burner is operating at stoichiometric conditions. The highest efficiency was obtained for the darkest coloured powder. The energy efficiency was also found to increase with burner temperature. However, the quality of the cured surface tended to decrease if the temperature rise was significant.

A comment on dielectric hole burning

The method of dielectric hole burning is used to distinguish a homogeneous broadened spectrum from a distribution of relaxation times in a dielectric material. After stimulation with a sinusoidal high electric field a time-dependent shift of the response function Φ(t) is observed. This shift is considered to be induced by a frequency selective absorption of energy and an increase of a local fictive temperature. A computer simulation, which is based upon the model of asymmetric double-well potentials for dipole orientations, also shows a time-dependent shift of the response function after applying and removing a sinusoidal high electric field. This behavior is explained considering the time-dependent polarization only. It is shown in this article that it is not necessary to assume an increase of a local fictive temperature caused by a frequency selective absorption of energy.

Review and Assessment of Radio-frequency and Microwave Energy for Stored-grain Insect Control

Fundamental principles of radio-frequency (RF) and microwave dielectric heating are presented, with a basic consideration of differential or selective absorption of energy from RF and microwave fields that might be applicable for stored-grain insect control. Experimental findings of the past 50 years are reviewed, with respect to entomological and physical factors affecting the response of insects exposed to RF and microwave electromagnetic fields in grain and grain products. Practical aspects of RF and microwave energy application for stored-grain insect control are considered, and it is concluded that such use is highly unlikely without some new discovery of a nonthermal lethal mechanism that might be exploited for this purpose.

Effect of blood upon the selective ablation of atherosclerotic plaque witha pulsed dye laser

Laser angioplasty systems with laser energy preferentially absorbed by atherosclerotic plaque may offer a safe method of plaque removal. This study evaluated the effect of blood upon selective energy absorption using a pulsed dye laser at 480 nm. Intra-arterial laser irradiation of normal rabbit femoral arteries demonstrated a perforation threshold energy with blood perfusion of 13.1 mJ per pulse compared to 87.9 mJ with saline (P less than .0001), indicating a deleterious effect in the presence of blood. An adverse effect upon arterial healing at 3 days was noted in sheep following intra-arterial irradiation during blood but not saline perfusion. Normal and atherosclerotic human aorta ablation thresholds differed significantly (P less than .0002) under saline (plaque: 20 mJ and normal: 120 mJ) but the difference under blood (plaque: 5 mJ and normal: 20 mJ) was not significant. We conclude that absorption of laser energy by blood can reduce the effect of differential absorption by endogenous chromophores in normal and pathologic vascular tissues and, therefore, removal of blood may be a prerequisite for selective ablation of atherosclerotic plaques.

Surgery by laser for malignant melanoma.

Lasers have been used for photocoagulation and photoexcision of malignant melanomas when conventional instruments could not be used. Lasers are useful for destruction of cutaneous metastases from malignant melanomas especially when numerous and dispersed. The color of melanomas makes for selective absorption of energy from lasers in the visible light range. Surgery by lasers is still an investigative form of surgery with current research studies on immediate placement of grafts, lymphatic migration of malignant cells after laser surgery, and relevant immunologic studies.

Effect of aromatic groups on localization of high energy in cellulose

AbstractWhen γ‐radiation from 60Co interacted with fibrous cotton cellulose, the localization of at least part of the high energy resulted in cellulosic chain cleavage and loss in breaking strength of the irradiated fibers. The substitution of aromatic groups on the cotton cellulose molecule affected this localization of energy and decreased the radiation degradation of the fiber. The nature of the linkage of the aromatic group to the cellulose molecule was not as important as the radiation stability of the linkage. For example, if localization of energy occurred which cleaved the aromatic group from the cellulose molecule, the radioprotection of the cellulosic molecular chain by the aromatic group was not effective. If the aromatic group was so modified that the effective number of π‐electrons was decreased, the radioprotection of the cellulosic chain was also decreased. The radioprotection of the cellulosic molecular chain by benzhydryl, trityl, benzoyl, and cinnamoyl groups was effective over distances equivalent to several cellobiose units. The radioprotection of the cellulosic chain by naphthoyl groups was significant but not as effective as the listed groups. Due to the sharing of π‐electrons in the naphthoyl group, the effective number of π‐electrons was reduced, and consequently the radioprotective effect of the group was also reduced. Benzyl groups were cleaved from the cellulose molecule on irradiation and offered no radioprotection to the cellulosic chain, at least at the high radiation dosages used. The ESR spectra of the irradiated celluloses, both substituted and unsubstituted, were similar. This indicated that the presence of aromatic groups did not change the nature of the long‐lived free radicals induced in cellulose on irradiation. It was suggested that selective energy absorption by the aromatic group from the spur of high‐energy electrons produced on interaction of γ‐radiation with the cellulose molecule could account for the radioprotection of the cellulosic molecular chain.

Isotope Effects in the 77°K γ Irradiation of Ice

The radiation yields of H2, D2, and HD obtained by the 77°K γ irradiation of solute-free mixed H2O and D2O ice mixtures have been determined by use of mass spectroscopy. The total gas yields have been determined, too, both by use of a calibrated mass spectrometer and by manometric methods. Significant isotope effects were observed over a wide range of the isotopic compositions studied (i.e., the deuterium content varied from ∼0.016% to 99.8%). The separation factor αG=(H/D)gas(H/D)icevaried from about 70 for the high D content ice to about 1.0 for natural isotopic abundance ice. At (H/D)ice=1.0, αG is 1.7. Values of αG were obtained for 99.80% D2O over a temperature range of 4.2° to 196°K. The separation factor was found to be inversely proportional to temperature. The results of this study are compared with those in a previously published EPR study of stabilized H and D atoms after irradiation at 4.2°K. The observed effects are discussed briefly in terms of several models of selective energy absorption.

ENERGY PARTITION IN THE RADIOLYSIS OF AROMATIC MIXTURES1

Yields of products from the x irradiation of liquid benzene, pyridine, and their mixtures were investigated. The yields may be largely understood on the basis of the generation of precursors to all products in accordance with the electron fraction parameter. This is interpreted as placing limitations on a disproportionate role for direct excitation to low level states leading to selective energy absorption and as indicating a negligible role of intermolecular transfer of chemically consequential excitations in liquid aromatic systems. (auth)

A nondestructive technique for detecting internal discolorations in potatoes

A technique of nondestructively detecting internal discoloration in potatoes by light transmittance has been described. Preliminary investigations with hollow heart indicated that the discolored tissue exhibited a selective absorption of energy at 710 mώ. A measurement of the optical density difference between wavelengths at 800 mώ. and 710 mώ is used as the indication of discoloration. This measurement indicates discolorations associated with hollow heart, blackspot, and greening ; however, the apparatus used in this study was designed to examine potatoes for hollow heart. Results of limited tests showed that the method detected the presence of hollow heart 98 per cent of the time in a group of Irish Cobbler potatoes containing 61 per cent hollow heart. In a test with Katahdin potatoes 81 per cent of all discolored tubers were detected including potatoes with decay, greening, blackspot and hollow heart.

DISPERSION AND SELECTIVE ABSORPTION IN THE PROPAGATION OF ULTRASOUND IN LIQUIDS CONTAINED IN TUBES: Part I

An experimental study by the ultrasonic method of the phase velocity of longitudinal waves transmitted in liquids contained in tubes. Greatly augmented as well as largely decreased velocities may be obtained in any liquid by suitably adjusting the frequency of the wave or the diameter of the containing tube. This phenomenon, described here at length for the first time, is found to be caused by the selective absorption of energy of the longitudinal wave at certain frequencies, resulting in a velocity-frequency curve analogous to the "anomalous dispersion" curve of optics. In the experiments there is strong indication that the absorbing frequency depends inversely on the diameter of the tube.The fact that the absorption frequency does not depend on the material or length of the tube, or for thin walls on the wall thickness, indicates that it is neither longitudinal nor flexural (lateral) vibrations in the tube walls which causes the phenomenon; and the fact that for any liquid the critical frequency shifts with change of diameter indicates that it is in the column of liquid itself that the energy absorption or transference takes place.These experiments show that it is only at frequencies far removed from absorption i.e., on the regular and flat portions of the velocity-frequency curve some distance from the discontinuity, that the usual theories of sound transmission may safely be applied.