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Ne Laser (ne + laser)
Selected AbstractsMeasuring dynamics of caspase-3 activity in living cells using FRET technique during apoptosis induced by high fluence low-power laser irradiation,LASERS IN SURGERY AND MEDICINE, Issue 1 2005Fang Wang MSc Abstract Background and Objectives Low-power laser irradiation (LPLI) has been used for therapies such as curing spinal cord injury, healing wound etc. Yet, the mechanism of LPLI remains unclear. In order to determine the effects of high fluence LPLI on cell growth and caspase-3 activity, we have measured the dynamics of caspase-3 activity during cell apoptosis induced by high fluence LPLI treatment. Study Design/Materials and Methods He,Ne laser was used to irradiate human lung adenocarcinoma cells (ASTC-a-1). Cell Counting Kit-8 was used for cytotoxicity assay. A fluorescent microscope was used to perform fluorescence resonance energy transfer (FRET) imaging. A luminescence spectrometer was used to acquire the fluorescent emission spectrum. Statistical analysis was performed with Student's paired t -test. Results Cytotoxicity assay showed that when light irradiation fluence exceeded 60 J/cm2, LPLI treatment induced ASTC-a-1 cell apoptosis in a fluence-dependent manner. FRET imaging and spectrofluorometric analysis demonstrated that caspase-3 was activated during high fluence LPLI-induced cell apoptosis. Conclusions Using FRET technique, we have reported that high fluence LPLI can induce human lung adenocarcinoma cells (ASTC-a-1) apoptosis. The activation of caspase-3 plays an important role in the apoptotic process. Lasers Surg. Med. 36:2,7, 2005. © 2005 Wiley-Liss, Inc. [source] Effects of Different Doses of Low Power Continuous Wave He,Ne Laser Radiation on Some Seed Thermodynamic and Germination Parameters, and Potential Enzymes Involved in Seed Germination of Sunflower (Helianthus annuus L.)PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2010Rashida Perveen In this study, water-soaked seeds of sunflower were exposed to He,Ne laser irradiation of different energies to determine whether or not He,Ne laser irradiation caused changes to seed thermodynamic and germination parameters as well as effects on the activities of germination enzymes. The experiment comprised four energy levels: 0 (control), 100, 300 and 500 mJ of laser energy and each treatment replicated four times arranged in a completely randomized design. The experimentation was performed under the greenhouse conditions in the net-house of the Department of Botany, University of Agriculture, Faisalabad. The seed thermodynamic parameters were calculated according to seed germination thermograms determined with a calorimeter at 25.8°C for 72 h. Various thermodynamic parameters of seed (,H, (,S)e, (,S)c, (,S)e/,t and (,S)c/,t) were affected significantly due to presowing laser treatment. Significant changes in seed germination parameters and enzyme activities were observed in seeds treated with He,Ne laser. The He,Ne laser seed treatment resulted in increased activities of amylase and protease. These results indicate that the low power continuous wave He,Ne laser light seed treatment has considerable biological effects on seed metabolism. This seed treatment technique can be potentially employed to enhance agricultural productivity. [source] Energy structure and micromechanism of photo-electromotive force effect in V-doped CdTe crystalsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2007Yu. P. Gnatenko Abstract For the first time photo-electromotive force (photo-EMF) measurements were carried out for CdTe crystals doped with V atoms as a result of the photogeneration of carriers from deep impurity centers to the conduction band. Tilted geometry was applied that allowed two-dimensional monitoring of the vi- bration source. The CdTe:V crystals were excited by a He,Ne laser with a wavelength of 1.15 ,m (,, = 1.08 eV) and P = 2 mW. The mechanism of the appearance of the holographic current in the CdTe:V crystals taking into account real defect structure was proposed. The frequency dependence of the ac photo-EMF (holographic) current for the CdTe:V crystals was measured. It was shown that a low cut-off frequency for a laser intensity I = 0.2 mW/mm2 equals 6.0 kHz, which corresponds to a response time of 26 ,s. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Low-energy helium,neon laser induces melanocyte proliferation via interaction with type IV collagen: visible light as a therapeutic option for vitiligoBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2009C-C.E. Lan Summary Background, The treatment of vitiligo remains a challenge for clinical dermatologists. We have previously shown that the helium,neon laser (He,Ne laser, 632·8 nm) is a therapeutic option for treatment of this depigmentary disorder. Objectives, Addressing the intricate interactions between melanocytes, the most important cellular component in the repigmentation scheme of vitiligo, and their innate extracellular matrix collagen type IV, the current study aimed to elucidate the effects of the He,Ne laser on melanocytes. Methods, Cultured melanocytes were irradiated with the He,Ne laser. Relevant biological parameters including cell attachment, locomotion and growth were evaluated. In addition, the potentially involved molecular pathways were also determined. Results, Our results show that in addition to suppressing mobility but increasing attachment to type IV collagen, the He,Ne laser stimulates melanocyte proliferation through enhanced ,2,1 integrin expression. The expression of phosphorylated cyclic-AMP response element binding protein (CREB), an important regulator of melanocyte growth, was also upregulated by He,Ne laser treatment. Using a specific mitochondrial uncoupling agent [carbonyl cyanide m-chlorophenyl-hydrazone (CCCP)], the proliferative effect of the He,Ne laser on melanocytes was abolished and suppression of melanocyte growth was noted. Conclusions, In summary, we have demonstrated that the He,Ne laser imparts a growth stimulatory effect on functional melanocytes via mitochondria-related pathways and proposed that other minor pathways including DNA damage may also be inflicted by laser treatment on irradiated cells. More importantly, we have completed the repigmentation scheme of vitiligo brought about by He,Ne laser light in vitro and provided a solid theoretical basis regarding how the He,Ne laser induces recovery of vitiligo in vivo. [source] Single photon fluorescent microlithography for live-cell imagingMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2010Darío Kunik Abstract Using fluorescent dyes to trigger the polymerization of a commercial polyurethane resin allows a rapid fabrication of micrometer and submicrometer sized fluorescent structures by one-photon absorption. Here, we show that standard He,Ne lasers emitting at 632.8 nm can be used to start the photopolymerization and that very low laser power is required. This procedure allows the fabrication of fiduciary fluorescent references on standard glass coverslips, mica sheets, or gold-coated coverslips for laser scanning or standard fluorescent microscopy. The biocompatibility of the polymerized resin with cells in culture was tested by growing Xenopus melanophores and a standard laser scanning microscope was used to demonstrate that it is possible to use equipment readily available in several laboratories. We show that fluorescent structure with less than 10 nm in height may be used as references in fluorescence microscopy allowing a smooth environment for cell growth. Different dyes were tested and the conditions for one-photon polymerization were outlined. Microsc. Res. Tech. 2009. © 2009 Wiley-Liss, Inc. [source] | ||||||||||