Use Of Q-switched Nd Research Articles

Growth Aspects and Optical, Mechanical and Electrical Property Investigation on L-Histidinium-4-Nitrophenolate 4-Nitrophenol (LHPNP) Single Crystal

An organic nonlinear optical crystal of L-histidinium-4-nitrophenolate 4-nitrophenol (LHPNP), was grown by employing the conventional growth process of slow evaporation method. The grown LHPNP crystal was characterized by the spectral measurement (FTIR, UV-Visible, and PL) and Vicker’s hardness test. The grown crystal was found to be in the system of monoclinic with non-centrosymmetric space group P21 with dimension 12 × 9 × 6 mm3. The optical band gap value of the LHPNP crystal is Eg = 2.71 eV. The dielectric studies (dielectric constant, dielectric loss and ac conductivity) of the grown crystal were measured for the frequency ranging between 100 Hz and 1200 Hz. The thermal stability of the grown crystal has been put forth by the standard thermal method of TG-DTA. The LDT analysis was carried out making use of Q-switched Nd: YAG laser and the value of LDT is estimated to be greater as compared to KDP. The SHG efficiency of the grown crystal of LHPNP is 3.5 times greater than that of a standard KDP crystal. The Hirshfeld Analysis has been carried out to understand the crystal surface properties, stability and intermolecular interaction of the LHPNP crystal.

Effect of 1064-nm Q-switched Nd:YAG laser on invasiveness and innate immune response in keratinocytes infected with Candida albicans.

Candida albicans is an opportunistic pathogen commensal in the oral cavity, vagina, and healthy skin. Common therapeutic options for fungal infections are topical or systemic antifungal drugs. Recently, in cutaneous pathologies, lasers and light-based treatments have emerged showing few contraindications and minimal side effects. The Q-switched (Nd-YAG) laser at a wavelength of 1064nm has been shown to be useful in dermatology, dentistry, and some other medical specialties. It is used to treat onychomycoses, warts, and wounds and in some other treatments. We analyzed the effect of Q-switched (Nd-YAG) laser 1064nm on human keratinocytes infected with C. albicans. In particular, we evaluated the effect of laser on invasiveness of C. albicans and on inflammatory and protective response of HaCaT cells infected. The results obtained did not show inhibitory, fungicidal, or fungistatic effects of laser on yeast; in addition, laser did not affect HaCaT vitality. HaCaT cells infected with C. albicans and irradiated with laser showed a reduction of invasiveness of TNF-α and IL8 gene expression and an increase of immunomodulatory cytokines such as TGFβ. Furthermore, laser induces a significant over-expression of HSP70B (heat shock protein) and of HBD-2 (Human β defensin-2) in HaCaT infected with C. albicans, compared to the untreated control. The use of Q-switched Nd:YAG laser in skin mycosis caused by C. albicans reduces yeast invasiveness in keratinocytes, downregulates inflammatory activities, and facilitates cytoprotection and antimicrobial defense. Our results offer a promising therapeutic strategy in the management of skin candidiasis, also in combination with conventional therapies.

The use of Q-switched Nd:YAG laser in the treatment of superficial pigmented lesions in Koreans

AIM: There are still insufficient clinical reports concerning quality-switched Nd:YAG laser (QSNYL) in the treatment of superficial pigmented lesions in Asians. The purpose of this study was to analyse the efficacy and side effect profiles of QSNYL-assisted pigment removal in brown skin. METHODS: A total of 71 patients, presenting a wide gamut of superficial epidermal lesions, were treated with QSNYL. Clinical responses were assessed by comKeywords: paring photographs that were taken serially in every treatment. RESULTS: Treatment using the QSNYL is reported individually for the various superficial pigmented lesions in the skin of Korean patients. CONCLUSION: QSNYL may be a beneficial alternative tool for the treatment of a number of benign pigmented lesions including freckles, lentigines and unilateral lentiginosis.

The use of Q-switched Nd:Yag laser for removal of permanent eyeliner tattoo.

We present the results of a pilot study of the use of Nd:Yag laser in the removal of permanent eyeliner tattoos. Fourteen eyelids were treated, and in all cases a reduction in pigmentation was achieved although responses were variable. The advantages of such therapy over existing techniques are described. The technique offers a useful reduction of permanent eyeliner pigmentation and is particularly suited to treatment of localized areas of imperfect application or pigment migration.

Photodynamic therapy using pheophorbide-a and Q-switched Nd:YAG Laser on implanted human hepatocellular carcinoma

To evaluate whether administration of pheophorbide-a, a new photosensitizer, followed by use of Q-switched Nd:YAG laser produces a photodynamic reaction, we administered pheophorbide-a to female nude mice (BALB/c-nu) that had been implanted with human hepatocellular carcinoma. Intra-tumoral concentrations of pheophorbide-a were measured by high-performance liquid chromatography. 3 hours after peroral administration of 1 mg/kg body weight, the intra-tumoral concentration was too low to reveal photodynamic effects. Peroral administration of 250 mg/kg body weight, intra-peritoneal administration of 5 mg/kg body weight, and intra-tumoral injection of 200 micrograms yielded 0.24 micrograms/g, 0.83 micrograms/g and 3.68-108 micrograms/g tumor concentrations, respectively. All tumors were irradiated interstitially using a Q-switched Nd:YAG laser at 1064 nm. Only tumors that had been intra-tumorally injected had areas of necrosis larger than those in control tumors. The results suggest that the injection of pheophorbide-a followed by interstitial irradiation using a Q-switched Nd:YAG laser does not induce sufficient photodynamic reaction if the intra-tumoral pheophorbide-a concentration is less than 0.83 micrograms/g tumor tissue, and that photodynamic therapy may be useful if the pheophorbide-a tumor concentration is within the range of 0.83-108 micrograms/g.

Nd:YAG Laser Photodisruption of the Lens Nucleus Before Phacoemulsification

We studied the use of Q-switched Nd:YAG laser pulses to soften sclerotic lens nuclei before phacoemulsification. We obtained 105 lens nuclei from extracapsular cataract extractions, graded them for degree of sclerosis, and randomized them into laser treatment (53 lenses) or control groups (52 lenses). The treated lenses received laser pulses until confluent pits and clefts were visible. All lenses were phacoemulsified and the times recorded. Nd:YAG laser pretreatment decreased phacoemulsification time in all grades. In moderately sclerotic nuclei, average phacoemulsification time was reduced from 40.1 to 23.9 seconds (40.4%). The nuclei of ten lenses obtained from intracapsular cataract extractions were treated intracapsularly, and the posterior capsule was inadvertently ruptured in five.