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At least 181 records · Page 10Linked to original sources
PubMed2006

Effect of low-level helium-neon laser therapy on the healing of third-degree burns in rats.

This paper presents the results of a study on the effects of low-level helium-neon laser therapy (LL He-Ne LT) on the healing of burns. Seventy-eight adult male rats, having been subjected to third-degree burns, were randomly divided into four groups: two laser treated groups (n=20, each), one control group (n=19) and one nitrofurazone treated group (n=19). In the two laser treated groups, the burns were treated on a daily basis with LL He-Ne LT with an energy density of 1.2 and 2.4 J/cm(2), respectively. The response to treatment was assessed histologically at 7, 16 and 30 days after burning, and microbiologically at day 15. Analysis of variance showed that the mean of blood vessel sections in the 1.2J/cm(2) laser group was significantly higher than those in the other groups and the mean of the depth of new epidermis in the 2.4 J/cm(2) laser group on day 16 was significantly lower than in the nitrofurazone treated group (P=0.025, P=0.047, respectively). When Staphylococcus aureus and Pseudomonas aeruginosa grew in more than 50% of samples obtained from control group, there were no S. aureus and P. aeruginosa in the samples of 2.4 J/cm(2) laser group. It is concluded that LL He-Ne LT induced the destruction of S. aureus and P. aeruginosa in third-degree burns of rats, yet at the same time our histological findings showed that LL He-Ne LT caused a significant increase in the mean of blood vessel sections on day 7 after third degree burns and a decrease in the mean of the depth of new epidermis on day 16 after the same burns in rats.

Animals↗
PubMed2005

Laminar cortical dynamics of 3D surface perception: stratification, transparency, and neon color spreading.

The 3D LAMINART neural model is developed to explain how the visual cortex gives rise to 3D percepts of stratification, transparency, and neon color spreading in response to 2D pictures and 3D scenes. Such percepts are sensitive to whether contiguous image regions have the same contrast polarity and ocularity. The model predicts how like-polarity competition at V1 simple cells in layer 4 may cause these percepts when it interacts with other boundary and surface processes in V1, V2, and V4. The model also explains how: the Metelli Rules cause transparent percepts, bistable transparency percepts arise, and attention influences transparency reversal.

Color Perception↗
PubMed1988

Increase in the ADP/ATP exchange in rat liver mitochondria irradiated in vitro by helium-neon laser.

To gain some insight into the mechanism of cell photostimulation by laser light, measurements were made of the rate of ADP/ATP exchange in mitochondria irradiated with the low power continuous wave Helium Neon laser (energy dose 5 Joules/cm2). To do this a method has been developed to continuously monitor ATP efflux from phosphorylating mitochondria caused by externally added ADP, by photometrically following the NADP+ reduction which occurs in the presence of glucose, hexokinase, glucose-6-phosphate dehydrogenase and effluxed ATP. The NADP+ reduction rate shows hyperbolic dependence on ADP concentration (Km and Vmax values 8.5 +/- 0.87 microM and 20.7 +/- 0.49 nmoles NADP+ reduced/min x mg mitochondrial protein, respectively), and proves to measure the activity of the ADP/ATP translocator as shown by inhibition experiments using atracyloside, powerful inhibitor of this carrier. Irradiation was found to enhance the rate of ADP/ATP antiport, with externally added ADP ranging between 5 and 100 microM. As a result of experiments carried out with mitochondria loaded with either ATP or ADP, the increase in the activity of the ADP/ATP translocator is here proposed to depend on the increase in the electrochemical proton gradient which occurs owing to irradiation of mitochondria.

Adenosine Diphosphate↗
PubMed1997

Sister chromatid exchange induction in sheep peripheral blood mononuclear cells by helio-neon laser radiation.

The effects of laser light on the cellular DNA have not been extensively characterized. Low-power laser sources, such as the helium-neon (He-Ne) laser with a wavelength of 632.8 nm, have been found to produce photobiological and photodamage effects with evidence of interference with cell replication. We have investigated the effects of He-Ne laser irradiation on sister chromatid exchange (SCE) frequencies in sheep peripheral blood mononuclear cells (PBMC). Cultured cells were irradiated once at 6 selected energy intensities of laser irradiation and then stimulated with pokeweed mitogen and cultured in the presence of 5-bromodeoxyuridine (BrdUrd). The frequency of SCEs of both irradiated and non-irradiated cells were analyzed. The mean SCE of irradiated cells significantly increased with growing energy density up to a laser dose of 24 J/cm2, whereas after an energy density of 24 J/cm2, the SCE frequency decreased with increasing energy densities. We concluded that the application of He-Ne laser irradiation at energy densities ranging from 2 to 96 J/cm2 produced a different effect on SCE frequency in sheep PBMC in vitro.

Animals↗
PubMed1997

Additive effect of luminance and color cues in generation of neon color spreading.

A series of experiments were designed to examine how luminance and color cues influence the occurrence of neon color spreading for the Ehrenstein pattern plus the cross pattern. The proportion of "see" responses for color spreading was obtained for different combinations of the luminance and color of the pattern components. The following were obtained. (1) Increase in the luminance of the inducing pattern and/or the color difference between the cross and the inducing pattern raised the proportion of "see" responses for color spreading. This implies that luminance and color signals additively contribute to the generation of the color spreading, but in different ways. (2) The "iso-spreading contours" for the generation of color spreading were determined on the two-dimensional isoluminant plane composed of the L-M and S-(L+M) axes. The contours were approximately described by rotated quadratic or ellipse functions. The additive interaction within the chromatic systems [the L-M system and the S-(L+M) system] was less significant than that across the luminance and chromatic systems. (3) The pattern of the experimental results could not be explained straightforwardly by existing models.

Color Perception↗
PubMed2005

Infrared spectrum of Hg(OH)2 in solid neon and argon.

Mercury(II) hydroxide molecules have been prepared upon mercury arc lamp irradiation of Hg, H(2), and O(2) mixtures in solid neon and argon. The strongest three infrared absorptions are identified through isotopic substitution (D(2), HD, (18)O(2), (16)O(18)O) and comparison to frequencies from DFT calculations. The isolated Hg(OH)(2) molecule is stable and has a linear O-Hg-O linkage in a C(2) structure with an 86 degrees dihedral angle. However, in aqueous solution Hg(2+) and 2OH(-) may form an Hg(OH)(2) intermediate, which eliminates water and precipitates solid HgO: The solid Hg(OH)(2) compound is not known.

Journal Article↗
PubMed2002

Infrared spectrum of the novel electron-deficient BH(4) radical in solid neon.

Laser-ablated boron reacts with hydrogen on condensation in excess neon to give BH4 radical, BH4- anion, and B2H6 as the major products. Identifications are based on 10B and D substitution, DFT frequency calculations, and comparison to previous spectra. Infrared spectra of BH4 support the C2v structure deduced from previous ESR spectra and theoretical calculations with two normal B-H bonds and two long B-H bonds for this novel electron-deficient radical. NBO analysis suggests that the two long B-H bonds and the H- -H bond are one-electron bonds.

Journal Article↗
PubMed2005

Electronic absorption spectra of C3Cl, C4Cl, and their ions in neon matrices.

Electronic absorption spectra of C3Cl, C3Cl+, C3Cl-, C4Cl, and C4Cl+ have been recorded in 6 K neon matrices following mass selection. Ab initio calculations were performed (CCSD(T) and CASSCF) to identify the ground and accessible excited states of each molecule. The estimated excitation energies and transition moments aid the assignment. The absorptions observed for C3Cl are the 5(2)A' <-- X(2)A' and 3(2)A'' <-- X(2)A' transitions of the bent isomer and the (2)A1 <-- X(2)B2 transition of the cyclic form in the UV (336.1 nm), visible (428.7 nm), and near-IR (1047 nm) regions, respectively. The band systems for bent C3Cl- (435.2 nm) and linear C3Cl+ (413.2 nm) are both in the visible region and correspond to 2(1)A'' <-- X(1)A' and (1)pi <-- X(1)sigma+ type transitions. The C4Cl and C4Cl+ chains are linear, and the band origins of the 2(2)pi <-- X(2)pi and 2(3)pi <-- X(3)pi electronic transitions are at 427.0 and 405.7 nm. The spectral assignments are supported by analysis of the vibrational structure associated with each electronic transition.

Journal Article↗
PubMed2006

3Sigma- -X 3Sigma- electronic transition of linear C6H+ and C8H+ in neon matrixes.

The electronic absorption spectra of linear C6H+ and C8H+ were recorded in 6 K neon matrixes following mass selective deposition. The (1) 3Sigma- -X 3Sigma- electronic transition is identified with the origin band at 515.8 and 628.4 nm for l-C6H+ and l-C8H+, respectively. One strong (near 267 nm) and several weaker electronic transitions of l-C8H+ have also been observed in the UV. The results of ab initio calculations carried out for linear and cyclic C6H+ are consistent with the assignment.

Journal Article↗
PubMed2006

Electronic absorption spectra of the protonated polyacetylenes H2CnH+ (n = 4, 6, 8) in neon matrixes.

Electronic absorption spectra of the protonated polyacetylenic chains H2CnH+ (n = 4, 6, 8) and the neutral H2C8H have been observed in 6 K neon matrixes after mass selection. The wavelength of the H2CnH+ electronic transitions depends quasi-linearly on n, typical of carbon chains. The origin band is at 286.0, 378.6, and 467.6 nm for n = 4, 6, and 8, respectively. Two ground-state vibrations of H2C4H+ in the IR absorption spectrum were also detected. On the basis of the spectroscopic trends and the assignment of the vibrational frequencies in the ground and excited electronic states, it is concluded that the H2CnH+ species are C(2v) linear carbon chains with one H atom on one end and two on the other.

Journal Article↗
PubMedDate not supplied

Low-energy helium-neon laser irradiation and the tensile strength of incisional wounds in the rat.

Low-level laser energy has been reported to modulate the wound healing process in some but not all studies. To examine this hypothesis, we investigated incisional wounds made on the dorsal pelt of rats for changes in the healing produced by low-level irradiation with a helium-neon laser. The incisions were made with a scalpel and closed with sutures. The rats were irradiated daily for 12 days with four levels of laser light (0.0, 0.47, 0.93, and 1.73 J/cm(2)). Analysis of wound tensile strength indicated a possible strengthening of fresh wounds at the highest levels of irradiation (1.73 J/cm(2)). No change was observed in the tensile strength of formalin-fixed wounds. The distribution of measured tensile strengths did not follow normal statistics; instead they showed a platykurtic distribution. Using resampling statistics, where no assumption is made as to the nature of the distribution, we found that the results were contrary to other studies: no biostimulatory effect was seen.

Journal Article↗
PubMed2000

The influence of helium-neon laser irradiation on the viability of skin flaps in the rat.

Low energy helium-neon (He-Ne) laser irradiation has been shown to induce various therapeutic effects. We investigated its effect on the viability of skin flaps in the rat. Thirty rats underwent skin flap elevation and were then divided into three equal groups. Group I (control) was not irradiated. Groups II and III were irradiated for 5 days postoperatively, Group II to the transition zone (between the live and expected necrotic areas) and Group III to the transitional and distal zones; total energy, 2.9 J/cm(2)for each rat. Ten days after the last treatment larger surviving areas were demonstrated macroscopically in Groups II and III (P< 0.01 and 0.001, respectively). Histological examination showed tremendous proliferation of capillaries (P</= 0.05) and fibroblasts in the responsive irradiated areas. In conclusion, postoperative low-energy (2.9 J/cm(2)) He-Ne laser irradiation of the expected ischaemic zone of the rat flap can enlarge the surviving area. Irradiation of the whole expected ischaemic zone seems to be superior to irradiating the transition zone alone.

Animals↗
PubMed2004

High resolution measurements of kinetic energy release distributions of neon, argon, and krypton cluster ions using a three sector field mass spectrometer.

Using a newly constructed three sector field mass spectrometer (resulting in a BE1E2 field configuration) we have measured the kinetic energy release distributions of neon, argon, and krypton cluster ions. In the present study we used the first two sectors, B and E1, constituting a high resolution mass spectrometer, to select the parent ions in terms of mass, charge, and energy, and studied the decay of those ions in the third field free region. Due to the improved mass resolution we were able to extend earlier studies carried out with a two sector field machine, where an upper size limit arose from the fact that several isotopomers contribute to a decaying parent ion beam when the cluster size exceeds a certain value. Furthermore we developed a new data analysis. It allows us to model also fragment ion peaks that are a superposition of different decay reactions and thus we can determine the average kinetic energy release for all decay reactions of a given cluster ion. In a further step we used these results to determine the binding energies of cluster ions Rg(n) (n> or =10) by applying finite heat bath theory. The smaller sizes have not been included in this analysis, because the validity of finite heat bath theory becomes questionable below n approximately 10. The present average kinetic energy releases and binding energies are compared with other experiments and various calculations.

Journal Article↗
PubMed2004

Electronic and infrared absorption spectra of linear and cyclic C6+ in a neon matrix.

Electronic and infrared absorption spectra of mass-selected C6+, generated by dissociative electron impact ionization of C6Cl6 and C6Br6, have been recorded in 6 K neon matrices. Linear and cyclic forms of C6+ have been observed. The 2Pig<--Chi2Piu electronic transition of linear C6+ has its origin band at 646 nm whereas for the (2) 2B2<--Chi2A1 system of the cyclic isomer it lies at 570 nm. An infrared active fundamental mode in the ground electronic state of C6+ is observed at 2092 and 1972 cm(-1) for the linear and cyclic isomer, respectively.

Journal Article↗
PubMed2004

Thermally stimulated exoelectron emission from solid neon.

In spite of the negative electron affinity of Ne atoms, appreciable concentrations of electrons can be trapped in solid neon layers formed by depositing the gas on a cold substrate with concurrent electron irradiation. These are trapped at defect sites, and can be promoted into the conduction band in an annealing experiment. They can then recombine with positive charges producing vacuum ultraviolet "thermoluminescence," but can also be extracted from the solid, and detected as an "exoelectron" current. The thermally stimulated exoelectron emission profiles of the electron current versus temperature reveal two broad features near 7.5 and 10 K. These are shown to correspond to two distributions of electron trapping sites with slightly differing activation energies. For the narrower, higher temperature maximum, an average activation energy of about 23 meV is deduced, in good agreement with predictions based on the theory of electronic defect formation.

Journal Article↗
PubMed2004

Infrared absorptions of the H(2)O ... H(2) complex trapped in solid neon.

When a sample of neon to which have been added less than 1% each of H(2) and H(2)O is deposited at 4.3 K, the infrared spectrum of the resulting solid includes an absorption by the vibrational fundamental of H(2), which is normally infrared inactive. New absorptions are also associated with the vibrational fundamentals of the H(2)O in the sample. Similar results are obtained for deuterium-enriched samples. The new peaks are assigned to the van der Waals complex of H(2)O with H(2). As has been found in earlier theoretical, gas-phase, and solid-state studies of this and closely related systems, the infrared absorptions arise principally from complexes involving ortho-H(2), for which J=1.

Journal Article↗
PubMed2004

Correlation energy extrapolation by intrinsic scaling. I. Method and application to the neon atom.

Remarkably accurate scaling relations are shown to exist between the correlation energy contributions from various excitation levels of the configuration interaction approach, considered as functions of the size of the correlating orbital space. These relationships are used to develop a method for extrapolating a sequence of smaller configuration interaction calculations to the full configuration-interaction energy. Calculations of the neon atom ground state with the Dunning's quadruple zeta basis set demonstrate the ability of the method to obtain benchmark quality results.

Journal Article↗
PubMed2005

Electronic absorption spectra of linear and cyclic C(n)(+) n=7-9 in a neon matrix.

The C(n)(+) n=7-9 cations were produced by electron-impact ionization of perchloronaphthalene, mass selected, and their electronic absorption spectra in 6 K neon matrices recorded. The linear and cyclic isomers of C7(+) and C8(+) are detected. Three systems of linear C7(+) are observed with origin bands near 770, 332, and 309 nm. The cyclic C7(+) shows two transitions near 676 and 448 nm. One system of linear C9(+) is observed commencing at 371 nm. Linear C8(+) shows five dipole-allowed electronic transitions from the X 2pi(g) ground state, and the strongest ones have the origin bands at 890.8 and 308.1 nm. Five electronic transitions of cyclic C8(+) are also discernible.

Journal Article↗