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PubMed2002

Microscopic distribution functions, structure, and kinetic energy of liquid and solid neon: quantum Monte Carlo simulations.

We have performed extensive path integral Monte Carlo simulations of liquid and solid neon, in order to derive the kinetic energy as well as the single-particle and pair distribution functions of neon atoms in the condensed phases. From the single-particle distribution function n(r) one can derive the momentum distribution and thus obtain an independent estimate of the kinetic energy. The simulations have been carried out using mostly the semiempirical HFD-C2 pair potential by Aziz et al. [R. A. Aziz, W. J. Meath, and A. R. Allnatt, Chem. Phys. 79, 295 (1983)], but, in a few cases, we have also used the Lennard-Jones potential. The differences between the potentials, as measured by the properties investigated, are not very large, especially when compared with the actual precision of the experimental data. The simulation results have been compared with all the experimental information that is available from neutron scattering. The overall agreement with the experiments is very good.

Journal Article↗

PubMed2004

Explanation for neon color effect of chromatic configurations on the basis of perceptual ambiguity in form and color.

Under reflected light conditions, we observed a neon color effect in a van Tuijl-type pattern for 30 combinations by pairing CMY inks. The results cannot be fully explained by Bressan's proposal as follows: (1) the illusory colors for the six configurations contradicted her predictions, (2) strong effects were not presented for complementary color pairs, and (3) for four configurations, the colors of line segments assimilated into those of the inducing patterns. Thus, the author proposes an hypothesis that the visual system treats neon color displays as ambiguous figures in form and color. This proposal can explain both illusory colors of the illusory area and those of the line segments themselves.

Color Perception↗

PubMed1990

[Comparative histological and light-microscopic cytomorphometric studies of the tissue repair processes in postoperative wound complications treated locally with helium-neon laser radiation or a proteolytic enzyme].

Morphological studies were carried out on tissue material, removed from wound peripheral parts during application of secondary sutures on 69 complete perineal wound dehiscences of parturients prepared by helium-neon laser irradiation according to a method described by us, as of wound peripheral parts of 15 perineal wound dehiscences, prepared by alphahymotripsin dissolved in a solution with vitamin C. Histological preparations were stained by hematoxilin-eosin by van Gieson (for collagenous fibres), by Weigert (for elastic fibres) and by Gomori (for reticular fibres). Light microscopic cytomorphometric studies were made by a graduated ocular micrometer on stained with hematoxilin-eosin tissue sections with the help of standard optical system. The results of the performed histological examinations give foundation to accept the occurred more active stimulation of inflammatory and proliferative phase of wound reparative process after laser therapy with helium-neon laser irradiation. Light microscopic cytomorphometric studies indicate the presence of more advanced in its development granulation tissue after laser therapy by means of activation of local immunocompetent cells.

Chymotrypsin↗

PubMed1991

[Enzyme status of blood cells in premature children during the treatment of omphalitis by helium-neon laser radiation].

Helium-neon laser radiation was employed in the treatment of 27 premature children suffering from omphalitis. It has been established that helium-neon laser radiation produces a favourable effect on the healing and epithelization of the umbilical wound, activates lymphocyte succinate dehydrogenase in premature children. The rate of wound healing correlates with the initial enzymic status, with the number of sessions of laser therapy and the general estimation of the previous development of the child in accordance with the prognostic coefficient of sepsis development.

Blood Cells↗

PubMed1991

The effects of the helium-neon laser on postsurgical discomfort: a pilot study.

It has been postulated that low-energy lasers (soft lasers) have analgesic capabilities. European investigators who have worked with these lasers have tried to explain this phenomenon as an interference with the mediation of the pain message and/or the stimulation of endorphin production. There does not appear, however, to be much well-controlled research to support these claims. This study has examined the effect of the helium-neon laser on post-surgical discomfort. Fifteen patients who had surgical removal of bilaterally symmetrical mandibular third molars were evaluated. Laser therapy was applied to one side of each patient's mouth with the other side serving as the control. A similar technique of application, without activation of the laser beam, was utilized on the control side. This study has demonstrated that the helium-neon laser (632.8 nanometre (nm) at 10 milliwatt (mW), when applied to the surgical site for three minutes immediately following third molar surgery, reduced postoperative pain on the day of surgery and on the first postoperative day. This finding was statistically significant.

Adolescent↗

PubMed1991

[The effect of helium-neon laser radiation on the energy metabolic indices of the myocardium].

It was shown in experiments on white rats, that intravenous and direct myocardium helium-neon laser irradiation leads to the some activation of lactate, glucose-6-phosphate, succinate and reduced NAD degydrogenases. During direct myocardium irradiation these changes are in a less degree. It is suggested that helium-neon laser irradiation displays some active influence on the energy metabolism enzymes of the myocardium, and the mechanisms of this action are discussed.

Animals↗

PubMed1991

[Helium-neon laser irradiation in combined treatment of children with suppurative diseases of the lungs and pleura].

The article discusses the results of treatment of acute ischemia of the pleura in 60 children with the use of intracavitary laser therapy. The empyema cavity was irradiated through a quartz flexible monocrystal light guide. The authors studied the effect of helium-neon laser beam on the empyema microflora, the condition of immunity, and the specific features of the clinical course of acute empyema of the pleura. Treatment by helium-neon laser radiation promotes rapid closure of bronchopleural fistulas, reduces the period of treatment, causes an immunocorrection effect, and does not exert a bactericidal effect on the flora.

Adolescent↗

PubMed1990

[The stimulating effect of helium-neon laser radiation on rabbit eyes].

Local and general reactions have been studied after subjecting a rabbit eye to dispersed helium-neon laser radiation, 8 x 10(-6) wt/cm-2, 10 min daily for 10 days. There were recorded increase of blood filling of the uveal tract of the eye, changes in the indices of systemic hemodynamics, systolic and diastolic pressure, stroke and minute volume of blood volume, activation of separate links of antioxidant system connected both with oxidation-reduction of thiol disulfide system and the functioning of antiperoxide enzymes. The activation of antioxidant system has a local character, the changes in the retina of the eye and pigmented epithelium is expressed stronger than in the peripheral blood. The results obtained speak about relationship between the stimulating effect of helium-neon laser radiation on the rabbit eye and activation of antioxidant system.

Animals↗

PubMed1990

Helium-neon laser treatment transforms fibroblasts into myofibroblasts.

The differentiation of myofibroblastic cells from normal human gingival fibroblasts in vitro has been established by transmission electron microscopy and quantitated by immunohistochemistry, using antigelsolin monoclonal antibodies. Untreated control cultures were compared to cultures exposed to Helium-Neon (He-Ne) laser irradiation. A direct and massive transformation of the cultured fibroblasts into myofibroblasts was observed as early as 24 hours after laser treatment, whereas control cultures were comprised of only resting fibroblasts and active fibroblasts. This in vitro induction of myofibroblasts may be analogous to that which occurs in vivo. Therefore we undertook a similar study using biopsies from gingival tissues after wisdom tooth extraction. Myofibroblasts were present in the connective tissue of laser-treated gums 48 hours after irradiation, but not in untreated contralateral control tissues. These data provide evidence that the primary biologic effect of the Helium-Neon laser on connective tissue is the rapid generation of myofibroblasts from fibroblasts. The induction of a phenotype with contractile properties may have clinical significance in the acceleration of the wound-healing process.

Actins↗

PubMedDate not supplied

[Use of helium-neon lasers in the treatment of postoperative wounds of the pharynx].

This paper presents the results of treatment of post-operative pharyngeal wounds in 54 tonsillectomized patients (residents of the Far North) using a helium-neon laser. The treatment had a significant analgetic and anti-inflammatory effect which was demonstrated by the so-called swallow test, bar-algisimetry, thermometry of the mucosa of the anterior palatine arches and mandibular area, and cytological examination of the exudate from the tonsillar niches. Application of a low energy helium-neon laser in tonsillectomized patients shortens the therapeutic period by 2 days.

Adolescent↗

PubMed1989

Effects of helio-neon laser radiation upon cellular cycle in a plant model.

The scope of this study was to investigate possible relationships between He-Neon laser radiation and mitotic and phase indices in meristematic cells of Allium cepa L. bulbs. Our results indicate that mitotic index increased after irradiation depending this modification on the time exposure and the potency of the He-Neon beam. Phase indices were also modified: frequency of prophase increased, while inter- meta- and anaphase decreased: telophases remain unchanged. These variations were significative only when the preparations were irradiated a) with 5 mW for 10 min. or more, b) with 10 mW or c) when the preparations were processed 60 min. after irradiation. These findings could not be attributed to thermal changes. Modifications in RNA or protein synthesis could be responsible.

Allium↗

PubMed1988

Chronic myofascial pain: management by low-output helium-neon laser therapy.

Therapeutic benefits of low-output helium-neon laser therapy have not been established, but laser therapy has been suggested as an effective means of treating many acute and chronic musculoskeletal pain syndromes. Although not released for general clinical use by the FA, the helium-neon laser has been promoted to physical therapists and athletic trainers as potentially useful for the treatment of pain syndromes. In particular, it has been proposed that it may be more effective than conventional measures such as medication and conventional physical therapy in the treatment of myofascial pain syndromes (fibrositis, fibromyalgia). The citations in the literature include only case reports. Sixty-two patients were treated by using acupuncture points. Two sessions of five treatments were given six weeks apart. A crossover double-blind technique was used in the treatments. The clinical responses were assessed using portions of the McGill Pain Questionnaire. No statistical difference between the treatment and the placebo groups could be determined.

Acupuncture Therapy↗

PubMedDate not supplied

[Reactivation of superoxide dismutase by the helium-neon laser irradiation].

When incubating SOD for two hours in the buffer with pH 6.0 practically complete loss of the activity of enzyme was observed at insignificant changes of the absorption spectra in the region of 450 and 680 nm. Irradiation of SOD solution with helium-neon laser resulted in the dose-dependent reduction of spectral and enzymic properties. Similar effect of the red light was also observed when SOD was inactivated with hydrogen peroxide: laser irradiation brought about the reduction of initial absorption spectrum of the enzyme. One can believe that the therapeutic effect of helium-neon laser radiation is conditioned, at least partially, by photochemical reactivation of SOD inactivated under pathological conditions (inflammation, hypoxia) in the tissues.

Enzyme Activation↗

PubMed1985

[Helium-neon laser--a possibility for the topodiagnosis of tracheal stenoses].

Exact knowledge of the upper and lower border of a tracheostenosis is important for success or failure in a transverse resection of the trachea. Using an angular optical equipment of 90 degrees, the upper margin of the stenosis can be focussed endoscopically in case of localisation problems, and projected on the front side of the trachea by the helium-neon laser beam. Even in case of tracheal displacement caused by a tumour, or induration of the soft tissues of the neck due to x-rays, the helium-neon laser beam will be an important orientation aid.

Endoscopes↗

PubMed1984

Inadequate effect of helium-neon laser on venous leg ulcers.

A study to determine whether laser radiation of low-power photon density would really affect the healing of venous leg ulcers in man was performed. The ulcers were irradiated 6 d per wk with a helium-neon laser (wavelength 632.8 nm). Energy densities of 1 J/cm2 (16 patients) and 4 J/cm2 (17 patients) were administered daily. The control group (28 patients) received only antiseptic local compresses as treatment. No statistically significant difference between the laser-treated group and the control group was found. It was concluded that helium-neon laser radiation has no advantages over standard local treatments, at least with the dosage schedules and protocols employed.

Adult↗

PubMed1984

[Effect of helium-neon laser radiation on the morphology of experimental allergic contact dermatitis].

Clinical and morphological studies of guinea-pig skin in the areas of dermatitis induced by application of dinitrochlorobenzene (DNCB) have shown the decreased skin response to DNCB after treatment with helium-neon laser (wave length 632.8 nm, power density 8-10 mvt /cm2). The ultrastructural signs of cell metabolism activation in the epidermis and derma as well as activation of capillary transport have been discovered in allergic contact dermatitis areas after treatment with helium-neon laser.

Animals↗

PubMed1997

Helium-neon laser irradiation is not a stressful treatment: a study on heat-shock protein (HSP70) level.

BACKGROUND AND OBJECTIVE: Helium-neon (He-Ne) laser irradiation has been clinically used to reduce chemotherapy-induced mucositis. This work was designed to find out if this treatment is stressful at the cellular level by studying its effects on the level of the stress-inducible heat shock proteins. STUDY DESIGN/MATERIALS AND METHODS: Human desmodontal and mouse L929 fibroblasts were irradiated using a 60 mW laser by a single application of 1.5 and 3J/cm2 in continuous mode. Heat shock protein level was studied by gel electrophoresis and Western blotting using monoclonal antibodies. RESULTS: He-Ne treatment does not induce heat shock protein synthesis in human desmodontal nor in mouse fibroblasts at the energy densities used in this study. CONCLUSIONS: These results indicate that the treatment is not stressful at the cellular level.

Animals↗

PubMed2001

Helium-Neon laser irradiation of hepatocytes can trigger increase of the mitochondrial membrane potential and can stimulate c-fos expression in a Ca2+-dependent manner.

BACKGROUND AND OBJECTIVE: To gain some insight into the photostimulation of isolated hepatocytes irradiated with Helium-Neon (He-Ne) laser light certain biochemical events were studied with respect to two mechanisms: i) the direct light dependent activation of certain biochemical events investigated in intact cells and isolated mitochondria, ii) the indirect stimulation of processes per se light independent. STUDY DESIGNS/MATERIALS AND METHODS: Irradiation of either isolated hepatocytes or isolated rat liver mitochondria was carried out with He-Ne laser (wavelength, 632.8 nm; fluence, 0.24 J cm-2; fluence rate, 12 mW cm-2). Changes in mitochondrial membrane potential in isolated hepatocytes were monitored using the cationic probe safranine. The c-fos expression was studied by Northern blot and immunoblot analysis. RESULTS: As a result of irradiation, increase of the mitochondrial membrane potential was found to occur in irradiated hepatocytes both in the presence or in the absence of CaCl2. The hyperpolarization of the mitochondrial membrane is assumed to cause an increase in mitochondrial Ca2+ uptake that was measured in isolated mitochondria. Finally, an increase in c-fos expression was found in irradiated hepatocytes when incubated in the presence of CaCl2. CONCLUSION: This paper gives additional information on the mechanism by which He-Ne laser light, either directly or in a cascade-like effect dependent on increase in cell Ca2+, can cause cell stimulation.

Animals↗