Red Visible Light Research Articles

Study on the subjective brightness of photonic crystal structural colored wood products

ABSTRACT Photonic crystal structural color is a novel method in the field of colored coating on the surface of wood products. However, the subjective brightness of photonic crystal structural colored wood products under different color temperature light sources has not been studied. In this study, poly(styrene-methyl methacrylate-acrylic acid) latex microspheres with different diameters were used to construct photonic crystal coatings on wood surface. The subjective brightness psychological quantity under different color temperature light sources was obtained. Combined with the optical properties of the coatings, the correlation between the physical optical properties of the photonic crystal coating, the color temperature of the light source and the subjective brightness of the coating was obtained. The photonic crystal coating in the near red visible light wavelength range had higher subjective brightness under low color temperature light source, and coating in the near purple visible light wavelength range had higher subjective brightness under high color temperature light source. The subjective brightness of the photonic crystal coating was very closely related to the light source color temperature and closely related to the reflectivity of the coating. This study expands the research on the optical properties of photonic crystal structure colored wood products.

Synthesis and Characteristics of Sr3La(PO4)3:Eu3+ Phosphor with Luminescence in NIR Biological Window

The Sr3La(PO4)3:Eu3+ (SLP:Eu3+) phosphor was prepared with the coprecipitation method, which emited red visible-light along with a near-infrared (NIR) luminescence in the biological window region. The influence of synthesis temperature and Eu3+ doping concentration on the characteristics of the phosphor was discussed. The optimal crystallinity was obtained when the phosphor was doped with 0.7 mol% of Eu3+ and annealed at 1200 °C for 2 h. The particle size was approximately 1 μm. As compared with the SLP:0.01 Eu3+, the photoluminescence intensity of the SLP:0.07 Eu3+ increased by 4.95-fold at wavelength of 615 nm and 3.97- fold at 705 nm. The red SLP:Eu3+ phosphor with a high NIR emission is a potential candidate material for bio-image and bio-sensor applications.

Effect of laser therapy on expression of angio- and fibrogenic factors, and cytokine concentrations during the healing process of human pressure ulcers.

Objective: To evaluate the effect of laser irradiation at different wavelengths on the expression of selected growth factors and inflammatory mediators at particular stages of the wound healing process.Methods: Sixty-seven patients were recruited, treated, and analyzed (group A - 940 nm: 17 patients; group B - 808 nm: 18 patients; group C - 658 nm: 16 patients; group D - sham therapy: 17 patients). Patients received a basic treatment, including repositioning and mobilization, air pressure mattress and bed support surfaces, wound cleansing and drug therapy. Additionally, patients received laser therapy once a day, 5 times a week for 1 month in use of a semiconductor lasers (GaAlAs) which emitted a continuous radiation emission at separate wavelengths of 940 nm (group A), 808 nm (group B) and 658 nm (group C). In group D (sham therapy), laser therapy was applied in the same manner, but the device was off during each session (only the applicator was switched on to scan pressure ulcers using none coherent red visible light).Results: The positive changes in the measured serum (IL-2, IL-6 and TNF-α) and wound tissue (TNF-α, VEGF and TGFβ1) parameters appeared to be connected only with the wavelength of 658 nm. The significant change in pro-inflammatory mediator levels [interleukin 2 (IL-2) with p=0.008 and interleukin 6 (IL-6) with p=0.016] was noticed after two weeks of laser therapy. In the other groups, the inflammation was also reduced, but the process was not as marked as in group C. Similarly, in the case of tumor necrosis factor (TNF-α) concentration, where after two weeks of treatment with irradiation at a wavelength of 658 nm, a rapid suppression was observed (p=0.001), whereas in the other groups, these results were much slower and not as obvious. Interestingly, again in the case of group C, the change in TNF-α concentration in wound tissue was most intensive (≈75% reduction), whereas the changes in other groups were not as obvious (≈50% reduction). After irradiation (658 nm), the VEGF expression increased significantly within the first two weeks, and then it decreased and maintained a stable level. In contrast, the TGFβ1 activity remained level, but always higher in comparison to other groupsConclusions: The effective healing of pressure ulcers is connected with laser irradiation at a wavelength of 658 nm. We believe that this effect is related to the inhibition of inflammatory processes in the wound and stimulation of angiogenesis and fibroblast proliferation at this specific radiation (based both on concentration of interleukins and TNF-α serum level and VEGF, TGFβ1, TNF-α activities in wound biopsies). Laser therapy at wavelengths of 940 and 808 nm does not significantly affect the above-mentioned repair processes, which explains its low effectiveness in the treatment of pressure ulcers.

Assessing of integration of ionizing radiation with Radachlorin-PDT on MCF-7 breast cancer cell treatment.

This study was undertaken to examine the effects of Radachlorin as a sensitizer in both photodynamic and radiation therapy on MCF-7 human breast cancer cell line. Another purpose was to assess the effectiveness of radiotherapy in combination with photodynamic therapy. The cells were incubated with Radachlorin and then exposed, in the independent treatment groups, to red visible light (660 nm), at two energy densities (6 and 12 j/cm(^)2) and 2-Gy X-ray ionizing radiation. In addition, combination effects of these modalities were evaluated. The percentage of the cell survival was investigated using the MTT assay and also survival fraction was evaluated by colony assay. The results demonstrated Radachlorin had no significant cytotoxic effects alone. However, it had a strong cytotoxic effect in the presence of light on MCF-7 cells. Light and Radachlorin reduced the percent of cell survival to 47 %. Despite Radachlorin could not act as a radiosensitizer, using integration of Radachlorin with radiotherapy and photodynamic therapy resulted in a significant cell death in comparison to the control group. Colony assay revealed the synergistic effect of this combined therapy with reduction of survival fraction to 0.03. MTT showed that the viability of breast cancer cells was reduced to 28 % by this integration therapy. Combination of radiation and photodynamic therapy could be a worthwhile approach for breast cancer treatment. It appears that we can reduce the adverse effects of treatments without reducing the efficacy of therapy.

광민감물질이 배제된 광선역학요법이 여드름 피부에 미치는 효과

At a dermatology during the skin care, photodynamic therapy(PDT) is carried after 5-aminolevulinic acid(ALA), light sensitive material, is applied. At a skin care shop, using drug is prohibited. Thus, the aim of this research was to see the effect of the acne skin by irradiating PDT to the skin without applying ALA. The research method was that 24 female undergraduates who had acne on their face at the level of mild or comedonal, and the participants were divided into four groups(group1: no treatment, group 2: 420 nm of blue visible light, group 3: 660 nm of red visible light and group 4: blue and red visible light). The participants of group 2, 3 and 4 were irradiated with visible light for 20 minutes per week for 6 weeks, and they were compared to group 1. As a result of the research, the number of erythema, sebum, papules and pustules of those who were irradiated with visible light decreased, and the pore size of those also decreased while the amount of moisture increased. If an skin care shop applies PDT to the existing acne skin care, that PDT will influence on the program of a skin care shop is expected.

Photophysical Properties of Chlorophyll Derivatives Linked with Rhenium Bipyridine Complexes

Abstract Since photochemical CO2 reduction using long wavelength regions of sunlight is important, we have reported the first photochemical CO2 reduction with red visible light (>650 nm) by using a synthetic chlorophyll derivative covalently linked with a rhenium bipyridine complex. In the reported system, electron/energy transfer from the photoexcited chlorophyll to the catalytic Re complex was not so effective. To accelerate the process for achieving efficient photochemical reduction of CO2, we controlled the redox potential of Re complex and improved the chlorophyll donor by a simple modification. As a result, we achieved strong quenching of the excited states of a 131-deoxochlorophyll derivative with a rhenium bipyridine complex in a molecule.

Enhanced photocurrent of Ge-doped InGaO thin film transistors with quantum dots

The photocurrent of germanium-doped indium-gallium oxide (GIGO) thin film transistors (TFTs) can be observed when the device is exposed to a ultra-violet light because GIGO is a wide band gap semiconducting material. Therefore, we decorated cadmium selenide (CdSe) quantum-dots (QDs) on the surface of GIGO to increase the photocurrent for low-energy light, i.e., visible light. A 10 nm GIGO film was deposited on the SiO2/Si substrate by a radio frequency sputter system. Also, we prepared CdSe QDs with sizes of ∼6.3 nm, which can absorb red visible light. QDs were spin-coated onto the GIGO film, and post-annealing was done to provide cross-linking between QDs. The prepared devices showed a 231% increase in photocurrent when exposed to 650 nm light due to the QDs on the GIGO surface. Measurements to construct an energy level diagram were made using ultraviolet photoelectron spectroscopy to determine the origin of the photocurrent, and we found that the small band gap of CdSe QDs enables the increase in photocurrent in the GIGO TFTs. This result is relevant for developing highly transparent photosensors based on oxide semiconductors and QDs.

Photochemical Reduction of CO2 with Red Light Using Synthetic Chlorophyll–Rhenium Bipyridine Dyad

Abstract We successfully performed the reduction of CO2 to CO by selective illumination of red visible light to a chlorophyll derivative covalently linked with a rhenium bipyridine complex. This is the first example of the photochemical reduction of CO2 using a sensitizer that has strong absorption at a wavelength over 650 nm.

Towards Matched Pairs of Porphyrin–ReI/99mTcI Conjugates that Combine Photodynamic Activity with Fluorescence and Radio Imaging

We recently prepared two novel water soluble porphyrins bearing a single peripheral chelator, either diethylenetriamine (1) or bipyridyl (2), tethered to one meso position. The preparation of their conjugates with a fac-{(99m) Tc(CO)3 }(+) fragment and the potential of these resulting conjugates as fluorescence and radio imaging tools were also described. In this work, we focused on the corresponding non-radioactive analogues that bear the fac-{Re(CO)3 }(+) fragment (diethylenetriamine 3 and bipyridyl 4). We report on the uptake, in vitro PDT activity, and cellular localization of Re(I) conjugates 3 and 4 in comparison to the parent porphyrins 1 and 2. Compounds 1-4 have modest or negligible cytotoxicity in the dark against HeLa human cervical cancer cells but become remarkably cytotoxic after exposure to moderate doses of red visible light (590-700 nm). This phototoxicity was found to be directly proportional to the total light dose. Although the four compounds show distinct uptake patterns, they have comparable PDT activity. Confocal fluorescence measurements showed that porphyrin 1 and its Re(I) conjugate 3 have different cellular localization patterns in HeLa cells.

The Effect of Methylene Blue in Combination with Red Visible Light on Model Viruses Inactivation and Coagulation Factors in Fresh Frozen Plasma

The Effect of Methylene Blue in Combination with Red Visible Light on Model Viruses Inactivation and Coagulation Factors in Fresh Frozen Plasma

Complementary, Holistic, and Integrative Medicine

Complementary, Holistic, and Integrative Medicine

Complementary, Holistic, and Integrative Medicine: Acne

1. Anju Sawni, MD* 2. Amritpal Singh, MD† 1. *Pediatric Education, Hurley Children’s Hospital/Hurley Medical Center, Flint, MI. 2. †Department of Dravyaguna (Medicinal Plants), Sri Dhanwantry Ayurvedic College, Chandigarh, India. * Abbreviations: EFAs: : essential fatty acid LTB4: : leukotriene B4 Acne vulgaris is a common skin disorder that affects ∼70% to 87% of adolescents and young adults. (1) The pathogenesis of acne is multifactorial and complex, and is thought to be due to androgen-stimulated sebum production. This production leads to follicular occlusion and hyperkeratinization, with comedo formation, as well as microbial colonization of pilosebaceous follicles by Propionibacterium acnes , leading to inflammatory papules and pustules. Conventional treatments for acne include salicylic acid, benzoyl peroxide, retinoids, and antibiotics (topical and systemic). However, symptoms may not always improve, and patients may have adverse reactions to conventional treatments and thus seek alternative treatments. Antibiotic resistance in P acnes also has been rising, thus promoting the need to look at alternative therapies. (2) The influence of diet on acne has been debated for decades. One review of the literature looking at the evidence for diet, face washing, and sunlight exposure in acne management concluded that the evidence is incomplete at best. (3) Another review did not support any link between acne and foods such as dairy products, chocolate, and fatty foods. (4) However, with more recent focus on diet and nutritional supplements, emerging research suggests that diet may be a factor, particularly in mediating the inflammation and oxidative stress of the acne process. (5)(6)(7) Western diets, with characteristically high glycemic indices, can elevate insulin and insulin-like growth factor 1 levels acutely and chronically. (5) These hormones stimulate adrenal and gonadal androgen production, leading to increased sebum production and acne. Frequent consumption of high-glycemic-index carbohydrates may repeatedly expose adolescents to acute hyperinsulinemia. Therefore, a low-glycemic-load diet may have a beneficial effect on acne. (6) A review …

Laser: Tissue Interaction and Its Application in Clinical Dentistry

In 1960, Theodore Maiman exposed a human tooth to his prototype Ruby laser. The emission wavelength of the laser at 633 nm (deep red visible light) offered no beneficial interaction with the tooth, with much of the energy transmitting the enamel and dentine with presumable attenuation by the pigmented pulpal tissue. The inconsistencies of laser-tissue interaction continue to pose some difficulty for the dental clinician; however, the development of many laser machines, amounting to a facility to produce laser photonic energy at several wavelengths between the visible and far infrared areas of the electromagnetic spectrum, addresses many of the inconsistencies. The oral cavity is a complex environment, where hard and soft tissues exist in close proximity and all within bacteria laden saliva. All oral tissues are receptive to laser treatment, but the biophysics governing laser-tissue interaction demands a knowledge of all factors involved in delivery of this modality. Through this knowledge, correct and appropriate treatment can be delivered in a predictable manner.

Single-mode waveguiding in bundles of self-assembled semiconductor nanowires

We report on waveguiding in bundles of parallel oriented semiconductor nanowires, self-assembled from colloidal CdTe nanocrystals in solution at room temperature. Individual bundles, as narrow as 170 nm, act as single-mode, subwavelength waveguides for red visible light. Losses are dominated by reabsorption and allow waveguiding over distances of micrometers. This renders self-assembled NW bundles candidates for low-cost, short-distance optical interconnects in hybrid electronic-photonic circuits.

Microwave-hydrothermal preparation of alkaline-earth-metal tungstates

Microwave-hydrothermal processing was employed to synthesize nanostructured alkaline-earth-metal tungstate compounds in environmentally friendly conditions not yet found in the literature: 110 °C for times ranging from 5 to 20 min. X-ray diffraction showed that crystalline, single-phase materials were produced, while electron microscopy evidenced nanostructured particles with different morphologies. Raman spectroscopy was used to probe short-range ordering and also to obtain a reliable set of spectra containing all the Raman-active bands predicted by group-theory calculations. The Raman spectra showed no extra feature, indicating that our method gave well-ordered materials without important tetrahedral distortions. Sintered ceramics were submitted to polarized Raman scattering in parallel- and cross-polarized configurations. The Eg modes were totally evidenced in a cross-polarized configuration, while Ag and Bg modes appeared in the parallel arrangement, in complete agreement with the theoretical predictions. Photoluminescence measurements showed broad, complex emission bands, which varied from the blue to the red visible light regions. These results are related to shallow and deep defects into the band gap, through the presence of oxygen vacancies in the complex clusters with metal cations and tungsten atoms.

UV-activated paramagnetic centers in high-κzirconia-silica thin films

Amorphous thin films of ${\text{Zr}}_{x}{\text{Si}}_{(1\ensuremath{-}x)}{\text{O}}_{2}$ have been prepared on fused silica substrates and investigated by electron paramagnetic resonance spectroscopy. A defect center was identified at $g=2.0085\ifmmode\pm\else\textpm\fi{}0.0004$ that is UV-light activated and photoquenched by red visible light. Its appearance is shown to depend on the amount of silicon in the films. Based on experimental results presented here as well as studies in other oxide-based materials such as amorphous ${\text{SiO}}_{2}$, we suggest that the UV-induced center in amorphous ${\text{ZrO}}_{2}(\text{Si})$ films is an oxygenic-hole center.

Directional reflectance of vegetation measured by a calibrated digital camera

Obtaining directional reflectance information for vegetation canopies is often an expensive and time-consuming process. We present here a simple approach based on the use of an inexpensive digital camera equipped with a wide-angle lens. By the imaging of a large homogeneous area, a single image captures multiple views of a vegetation canopy. This gives a directional reflectance distribution fully sampled for view direction and free of variations in Sun elevation and azimuth. We determined the radiometric response of the camera sensor CCD's at the focal point and then extended this calibration to the full CCD array by using averaged images of clear blue sky. We evaluated the utility of the system by obtaining directional reflectance distributions of two vegetation targets, grass (Lolium spp) and pine forest (Pinus radiata), for red visible light. The precision of the derived biangular pattern of reflectance was +/-7%.

Infrared spectrum of a symmetrical phosphine-ozone complex in solid argon

Cocondensation of Ar/PH/sub 2/ and Ar/O/sub 2/ samples at 12-18 K has produced sharp satellite absorptions at 1037.3 cm/sup -1/ below nu/sub 3/ of O/sub 3/ at 1039.9 cm/sup -1/, at 988.5 and 986.3 cm/sup -1/ below nu/sub 2/ of PH/sub 3/ at 994 cm/sup -1/, and at 705.2 cm/sup -1/ above nu/sub 2/ of O/sub 3/ at 704.4 cm/sup -1/. These bands, which photolyzed with red visible light and were reproduced on sample warming to allow reagent diffusion, are assigned to the PH/sub 3/-O/sub 3/ complex. A sharp sextet in /sup 16,18/O/sub 3/ experiments indicated a symmetrical attachment of ozone in the complex. The red visible photolysis is postulated to involve a charge-transfer mechanism. 32 references, 3 figures, 2 tables.