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  1. S-band multiwavelength Brillouin/Raman distributed Bragg reflector fiber lasers
    Zulkifli MZ, Ahmad H, Taib JM, Muhammad FD, Dimyati K, Harun SW
    Appl Opt, 2013 Jun 1;52(16):3753-6.
    PMID: 23736330 DOI: 10.1364/AO.52.003753
    A multiwavelength Brillouin/Raman distributed Bragg reflector fiber laser operating in the S-band region is proposed and demonstrated. The laser uses a 7.7 km long dispersion-shifted fiber with an effective mode area of 15 μm(2) as the Brillouin and Raman gain media simultaneously. Two 1420 nm laser diodes with a combined power of 372 mW are used as pump sources, while a fiber Bragg grating with a center wavelength of 1500 nm is used as a reflector in the cavity. The setup is capable of generating 6 clearly defined Stokes lines at the highest pump power, spanning from 1499.8 to 1500.3 nm with the even Stokes having relatively higher peak powers, between 1.4 and 3.5 dBm as compared to the odd Stokes, which have peak powers between -4.7 and -5.0 dBm. The output of the laser is very stable and shows little to no fluctuations over a monitoring period of 50 min.
    Matched MeSH terms: Lasers, Semiconductor
  2. Fulltext Heavy-Tailed Fluctuations in the Spiking Output Intensity of Semiconductor Lasers with Optical Feedback
    Lan BL, Masoller C
    PLoS One, 2016;11(2):e0150027.
    PMID: 26901346 DOI: 10.1371/journal.pone.0150027
    Although heavy-tailed fluctuations are ubiquitous in complex systems, a good understanding of the mechanisms that generate them is still lacking. Optical complex systems are ideal candidates for investigating heavy-tailed fluctuations, as they allow recording large datasets under controllable experimental conditions. A dynamical regime that has attracted a lot of attention over the years is the so-called low-frequency fluctuations (LFFs) of semiconductor lasers with optical feedback. In this regime, the laser output intensity is characterized by abrupt and apparently random dropouts. The statistical analysis of the inter-dropout-intervals (IDIs) has provided many useful insights into the underlying dynamics. However, the presence of large temporal fluctuations in the IDI sequence has not yet been investigated. Here, by applying fluctuation analysis we show that the experimental distribution of IDI fluctuations is heavy-tailed, and specifically, is well-modeled by a non-Gaussian stable distribution. We find a good qualitative agreement with simulations of the Lang-Kobayashi model. Moreover, we uncover a transition from a less-heavy-tailed state at low pump current to a more-heavy-tailed state at higher pump current. Our results indicate that fluctuation analysis can be a useful tool for investigating the output signals of complex optical systems; it can be used for detecting underlying regime shifts, for model validation and parameter estimation.
    Matched MeSH terms: Lasers, Semiconductor*
  3. S-band multiwavelength ring Brillouin/Raman fiber laser with 20 GHz channel spacing
    Ahmad H, Zulkifli MZ, Hassan NA, Harun SW
    Appl Opt, 2012 Apr 10;51(11):1811-5.
    PMID: 22505174 DOI: 10.1364/AO.51.001811
    We propose and demonstrate a tunable S-band multiwavelength Brillouin/Raman fiber laser (MBRFL) with a tuning range of between 1490 to 1530 nm. The proposed MBRFL is designed around a 7.7 km long dispersion compensating fiber in a simple ring configuration, acting as a nonlinear medium for the generation of multiple wavelengths from stimulated Brillouin scattering (SBS) and also as a nonlinear gain medium for stimulated Raman scattering (SRS) amplification. A laser source with a maximum power of 12 dBm acts as the Brillouin pump (BP), while two 1420 nm laser diodes with a total power of 26 dBm act as the Raman pumps (RPs). The MBRFL can generate a multiwavelength comb consisting of even and odd Stokes at an average power of -12 dBm and -14 dBm respectively, and by separating the even and odd Stokes outputs, a 20 GHz channel spacing is obtained between two consecutive wavelengths. Due to the four-wave mixing (FWM) effect, anti-Stokes lines are also observed. The multiwavelength comb generated is not dependent on the BP, thus providing high stability and repeatability and making it a highly potential source for many real-world applications. This is the first time, to the knowledge of the authors, that a tunable MBRFL has been developed using SRS to obtain gain in the S-band region.
    Matched MeSH terms: Lasers, Semiconductor
  4. Fulltext Temperature-insensitive bend sensor using entirely centered Erbium doping in the fiber core
    Ahmad H, Zulkifli MZ, Muhammad FD, Samangun JM, Abdul-Rashid HA, Harun SW
    Sensors (Basel), 2013;13(7):9536-46.
    PMID: 23881146 DOI: 10.3390/s130709536
    A fiber based bend sensor using a uniquely designed Bend-Sensitive Erbium Doped Fiber (BSEDF) is proposed and demonstrated. The BSEDF has two core regions, namely an undoped outer region with a diameter of about 9.38 μm encompassing a doped, inner core region with a diameter of 4.00 μm. The doped core region has about 400 ppm of an Er2O3 dopant. Pumping the BSEDF with a conventional 980 nm laser diode gives an Amplified Spontaneous Emission (ASE) spectrum spanning from 1,510 nm to over 1,560 nm at the output power level of about -58 dBm. The ASE spectrum has a peak power of -52 dBm at a central wavelength of 1,533 nm when not spooled. Spooling the BSEDF with diameters of 10 cm to 2 cm yields decreasing peak powers from -57.0 dBm to -61.8 dBm, while the central wavelength remains unchanged. The output is highly stable over time, with a low temperature sensitivity of around ~0.005 dBm/°C, thus allowing for the development of a highly stable sensor system based in the change of the peak power alone.
    Matched MeSH terms: Lasers, Semiconductor
  5. Optical properties of InGaAs/GaAs multi quantum wells structure grown by molecular beam epitaxy
    Mohd Sharizal Alias, Mohd Fauzi Maulud, Mohd Razman Yahya, Abdul Fatah Awang Mat, Suomalainen S
    Sains Malaysiana, 2008;37:233-237.
    Inclusive analysis on the optical characteristics of InGaAs/GaAs QW structure for 980 nm semiconductor laser operation is presented from experimental and theoretical point of view. The InGaAs/GaAs quantum well structure is grown by molecular beam epitaxy at different indium composition and quantum well thickness for optical characteristic comparison. Photoluminescence spectra from the measurement show that the spectrum is in good agreement with the simulation results. Detail simulation on the material gain for the InGaAs/GaAs quantum well as a function of carrier densities and operating temperature is also performed in order to optimize the semiconductor laser design for device fabrication.
    Matched MeSH terms: Lasers, Semiconductor
  6. Fulltext Determination of the difference on color changes of watermelons by laser light backscattering imaging
    Mohd Ali M, Hashim N, Bejo SK, Shamsudin R
    J Food Sci Technol, 2017 Oct;54(11):3650-3657.
    PMID: 29051660 DOI: 10.1007/s13197-017-2826-y
    The potential of laser light backscattering imaging was investigated for monitoring color parameters of seeded and seedless watermelons during storage. Two watermelon cultivars were harvested and stored for 3 weeks with seven measuring storage days (0, 4, 8, 12, 15, 18, and 21). The color parameters of watermelons were monitored using the conventional colorimetric methods (L*, a*, b*, C*, H*, and ∆E*) and laser light backscattering imaging system. A laser diode emitting at 658 nm and 30 mW power was used as a light source to obtain the backscattering image. The backscattering images were evaluated by the extraction of backscattering parameters based on the mean pixel values. The results showed that a good color prediction was achieved by the seedless watermelon with the R2 are all above 0.900. Thus, the application of the laser light backscattering imaging can be used for evaluating the color parameters of watermelons during the storage period.
    Matched MeSH terms: Lasers, Semiconductor
  7. Evaluation of structural and compositional changes on the root surface exposed to diode laser (810 nm): An In-vitro study
    Jayachandran D, Selvaraj S, Priya S, Kukkamalla MA, Senkalvarayan V
    Indian J Dent Res, 2023;34(1):19-23.
    PMID: 37417051 DOI: 10.4103/ijdr.ijdr_723_22
    BACKGROUND: The laser therapy has been used as an adjuvant for conventional periodontal disease as they exhibit a bactericidal effect on scaling and root planning by its thermal and photo disruptive effects on the pathogens. This study focuses on the structural and compositional changes induced on the root surfaces of teeth following diode laser (DL) application with increasing quantum of exposure time.

    OBJECTIVE: The objective of this study was to evaluate the structural and compositional changes on the root surface of extracted human permanent teeth after application of DLs (810 nm) with varying time interval.

    MATERIALS AND METHODS: Twenty samples of single-rooted periodontally compromised extracted teeth were utilized for this study. Root planning was done and the roughness caused by the instrumentation was measured using profilometric analysis. Then, the samples were divided into four groups, with DL application time: Group 1 - laser application for 15 s, Group 2 - laser application for 30 s, Group 3 - laser application for 45 s, and Group 4 - laser application for 60 s. A scanning electron microscope was used to examine the cemental surface and energy-dispersive X-ray analysis software assesses the compositional changes of the teeth in each group.

    RESULTS: This study reveals that on exposure of DL (810 nm) on the root surface when time of exposure increases, there were relative increases in surface irregularities and charring. There were significant changes in the chemical composition of the tooth surface.

    Matched MeSH terms: Lasers, Semiconductor/therapeutic use
  8. Fluorescent microscopy evaluation of diode laser effect on the penetration depth of turmeric (Curcuma longa) extract cream on skin tissues of Wistar rats
    Astuti SD, Mawaddah A, Kusumawati I, Mahmud AF, Nasution AMT, Purwanto B, et al.
    Lasers Med Sci, 2024 Feb 23;39(1):79.
    PMID: 38393433 DOI: 10.1007/s10103-024-04020-3
    The study investigates the effect of diode laser exposure on curcumin's skin penetration, using turmeric extraction as a light-sensitive chemical and various laser light sources. It uses an in vivo skin analysis method on Wistar strain mice. The lasers are utilized at wavelengths of 403 nm, 523 nm, 661 nm, and 979 nm. The energy densities of the lasers are 20.566 J/cm2, 20.572 J/cm2, 21.162 J/cm2, and 21.298 J/cm2, which are comparable to one another. The experimental animals were divided into three groups: base cream (BC), turmeric extract cream (TEC), and the combination laser (L), BC, and TEC treatment group. Combination light source (LS) with cream (C) was performed with 8 combinations namely 523 nm ((L1 + BC) and (L1 + TEC)), 661 nm ((L2 + BC) and (L2 + TEC)), 403 nm ((L3 + BC) and (L3 + TEC)), and 979 nm ((L4 + BC) and (L4 + TEC)). The study involved applying four laser types to cream-covered and turmeric extract-coated rat skin, with samples scored for analysis. The study found that both base cream and curcumin cream had consistent pH values of 7-8, within the skin's range, and curcumin extract cream had lower viscosity. The results of the statistical analysis of Kruskal-Wallis showed a significant value (p  0.05), while the treatment using BC and TEC showed a significant difference (p 
    Matched MeSH terms: Lasers, Semiconductor/therapeutic use
  9. Acoustic evaluation of photobiomodulation effect on in vitro human blood samples
    Suardi N, Germanam SJ, Rahim NAYM
    Lasers Med Sci, 2023 Apr 14;38(1):99.
    PMID: 37059895 DOI: 10.1007/s10103-023-03766-6
    Although positive photobiomodulation response on wound healing, tissue repair, and therapeutic treatment has been widely reported, additional works are still needed to understand its effects on human blood. This research carried out acoustic measurements using A-scan (GAMPT) ultrasonic techniques to elucidate the photobiomodulation effects on in vitro human blood samples as therapeutic treatment measures. The human blood samples were irradiated using a 532-nm laser with different output laser powers (60 and 80 mW) at various exposure times. The ultrasonic velocity measured in the human blood samples after laser irradiation showed significant changes, most of which were within the acceptance limit for soft tissues (1570 [Formula: see text] 30 m/s). Abnormal cells (echinocyte and crenation) were observed due to excessive exposure during laser treatment.
    Matched MeSH terms: Lasers, Semiconductor
  10. Biophotonic effect of diode laser irradiance on tensile strength of diabetic rats
    Lau PS, Bidin N, Krishnan G, Nassir Z, Bahktiar H
    J Cosmet Laser Ther, 2015 Apr;17(2):86-9.
    PMID: 25260140 DOI: 10.3109/14764172.2014.968587
    Low-energy laser irradiance at certain wavelengths is able to stimulate the tissue bio-reaction and enhance the healing process. Collagen deposition is one of the important aspects in healing process because it can increase the strength of the skin. This study was designed to examine the biophotonic effect of irradiance on collagen production of diabetic wound in rat model. The tensile strength of skin was employed as a parameter to describe the wound. Diabetic rat models were induced by streptozotocin via intravenous injection. Skin-breaking strength was measured using an Instron tensile test machine. The experimental animals were treated with 808-nm diode laser at two different powers-0.1 and 0.5 W/cm(2)-and 30, 60, and 120 s for each session. The tensile strength was optimized after treated with high-power diode laser. The photostimulation effect was revealed by accelerated healing process and enhanced tensile strength of wound. Laser photostimulation on tensile strength in diabetic wound suggests that such therapy facilitates collagen production in diabetic wound healing.
    Matched MeSH terms: Lasers, Semiconductor/adverse effects; Lasers, Semiconductor/therapeutic use*
  11. Fulltext 56 nm Wide-Band Tunable Q-Switched Erbium Doped Fiber Laser with Tungsten Ditelluride (WTe2) Saturable Absorber
    Ahmad H, Albaqawi HS, Yusoff N, Yi CW
    Sci Rep, 2020 Jun 17;10(1):9860.
    PMID: 32555280 DOI: 10.1038/s41598-020-66664-9
    A wide-band and tunable Q-switched erbium-doped fiber (EDF) laser operating at 1560.5 nm with a tungsten ditelluride (WTe2) saturable absorber (SA) is demonstrated. The semi-metallic nature of WTe2 as well as its small band gap and excellent nonlinear optical properties make it an excellent SA material. The laser cavity uses an 89.5 cm long EDF, pumped by a 980 nm laser diode as the linear gain while the WTe2 based SA generates the pulsed output. The WTe2 based SA has a modulation depth, non-saturable loss and saturation intensity of about 21.4%, 78.6%, and 0.35 kW/cm2 respectively. Stable pulses with a maximum repetition rate of 55.56 kHz, narrowest pulse width of 1.77 µs and highest pulse energy of 18.09 nJ are obtained at the maximum pump power of 244.5 mW. A 56 nm tuning range is obtained in the laser cavity, and the output is observed having a signal to noise ratio (SNR) of 48.5 dB. The demonstrated laser has potential for use in a large number of photonics applications.
    Matched MeSH terms: Lasers, Semiconductor
  12. Sub kGy photon irradiation alterations in graphite
    Bradley DA, Nawi SNM, Khandaker MU, Almugren KS, Sani SFA
    Appl Radiat Isot, 2020 Jul;161:109168.
    PMID: 32321700 DOI: 10.1016/j.apradiso.2020.109168
    Present work concerns polymer pencil-lead graphite (PPLG) and the potential use of these in elucidating irradiation-driven structural alterations. The study provides detailed analysis of radiation-induced structural interaction changes and the associated luminescence that originates from the energy absorption. Thermally stimulated emission from the different occupied defect energy levels reflects the received radiation dose, different for the different diameter PPLGs. The PPLG samples have been exposed to photon irradiation, specifically x-ray doses ranging from 1 to 10 Gy, extended to 30-200 Gy through use of a60Co gamma-ray source. Trapping parameters such as order of kinetics, activation energy and frequency factor are estimated using Chen's peak-shape method for a fixed-dose of 30 Gy. X-ray diffractometry was used to characterize the crystal structure of the PPLG, the aim being to identify the degree of structural order, atomic spacing and lattice constants of the various irradiated PPLG samples. The mean atomic spacing and degree of structural order for the different diameter PPLG are found to be 0.3332 nm and 26.6° respectively. Photoluminescence spectra from PPLG arising from diode laser excitation at 532 nm consist of two adjacent peaks, 602 nm (absorption) and 1074 nm (emission), with mean energy band gap values within the range 1.113-1.133 eV.
    Matched MeSH terms: Lasers, Semiconductor
  13. Fulltext Effect of 940 nm low-level laser therapy on osteogenesis in vitro
    Jawad MM, Husein A, Azlina A, Alam MK, Hassan R, Shaari R
    J Biomed Opt, 2013 Dec;18(12):128001.
    PMID: 24337495 DOI: 10.1117/1.JBO.18.12.128001
    Bone regeneration is essential in medical treatment, such as in surgical bone healing and orthodontics. The aim of this study is to examine the effect of different powers of 940 nm diode low-level laser treatment (LLLT) on osteoblast cells during their proliferation and differentiation stages. A human fetal osteoblast cell line was cultured and treated with LLLT. The cells were divided into experimental groups according to the power delivered and periods of exposure per day for each laser power. The (3-(4,5-dimethylthiazol-2yl)-2,5 diphenyl tetrazolium bromide) (MTT) assay was used to determine cell proliferation. Both alkaline phosphatase and osteocalcin activity assays were assessed for cell differentiation. All treatment groups showed a significant increase in cell proliferation and differentiation compared to the control group. Regarding the exposure time, the subgroups treated with the LLLT for 6 min showed higher proliferation and differentiation rates for the powers delivered, the 300-mW LLLT group significantly increased the amount of cell proliferation. By contrast, the 100 and 200 mW groups showed significantly greater amounts of cell differentiation. These results suggest that the use of LLLT may play an important role in stimulating osteoblast cells for improved bone formation.
    Matched MeSH terms: Lasers, Semiconductor*
  14. Fulltext In Vitro Mean Red Blood Cell Volume Change Induced by Diode Pump Solid State Low-Level Laser of 405 nm
    Musawi MS, Jafar MS, Al-Gailani BT, Ahmed NM, Suhaimi FM, Suardi N
    Photomed Laser Surg, 2016 May;34(5):211-4.
    PMID: 26966989 DOI: 10.1089/pho.2015.4043
    OBJECTIVE: This study was conducted to investigate the effects of low-level laser (LLL) doses on human red blood cell volume. The effects of exposure to a diode pump solid state (DPSS) (λ = 405 nm) laser were observed.

    BACKGROUND DATA: The response of human blood to LLL irradiation gives important information about the mechanism of interaction of laser light with living organisms. Materials and methods Blood samples were collected into ethylenediaminetetraacetic acid (EDTA)-containing tubes, and each sample was divided into two equal aliquots, one to serve as control and the other for irradiation. The aliquot was subjected to laser irradiation for 20, 30, 40, or 50 min at a fixed power density of 0.03 W/cm(2). Mean cell volume (MCV) and red blood cell (RBC) counts were measured immediately after irradiation using a computerized hemtoanalyzer.

    RESULTS: Significant decrease in RBC volume (p 

    Matched MeSH terms: Lasers, Semiconductor
  15. Fulltext The Integration of a Dual-Wavelength Super Pulsed Diode Laser for Consistent Tissue Ablation in the Esthetic Zone: A Case Series
    Kamar Affendi NH, Ahmad R, Vahidi F, Hassan MZ, Rahimi SN
    Case Rep Dent, 2020;2020:8883156.
    PMID: 33343944 DOI: 10.1155/2020/8883156
    Introduction: A diode laser is one of the universally compact accepted laser systems used fundamentally for soft tissue applications. Most diode laser devices have a single wavelength of either 810 nm for superior coagulation or 980 nm for tissue ablation. In these case series, the use of dual wavelengths (810 nm and 980 nm) in combination with super pulsing has provided a cleaner cut (no charring) with faster healing that eases the placement of the final restoration in the esthetic zone. Case Description. The present case series describe four cases in the esthetic zone that achieved hemostasis ablation without collateral damage to enhance gingival balance of definitive restoration. The gingivoplasty and gingivectomy modes are used to achieve efficient tissue ablation. Although there is no specific mode indicated in the FDA laser requirement for gingival depigmentation, the procedure could be safely performed with the dual-wavelength diode laser.

    Result: All four patients revealed a good esthetic outcome and reported no pain postoperatively. Healing was uneventful, and definitive restoration was delivered within two to four weeks postoperatively.

    Conclusion: Within the limitation of these case series, the dual-wavelength super pulsed diode laser has the capacity to deliver peak powers resulting in efficient cutting and less tissue charring and also as an alternative tool for removal of gingival pigmentation. Prospective clinical research with larger sample size is needed for conclusive results.

    Matched MeSH terms: Lasers, Semiconductor
  16. The antifungal agent of silver nanoparticles activated by diode laser as light source to reduce C. albicans biofilms: an in vitro study
    Astuti SD, Puspita PS, Putra AP, Zaidan AH, Fahmi MZ, Syahrom A, et al.
    Lasers Med Sci, 2019 Jul;34(5):929-937.
    PMID: 30413898 DOI: 10.1007/s10103-018-2677-4
    Candida albicans is a normal flora caused fungal infections and has the ability to form biofilms. The aim of this study was to improve the antifungal effect of silver nanoparticles (AgNPs) and the light source for reducing the biofilm survival of C. albicans. AgNPs were prepared by silver nitrate (AgNO3) and trisodium citrate (Na3C6H5O7). To determine the antifungal effect of treatments on C. albicans biofilm, samples were distributed into four groups; L + P+ was treatment with laser irradiation and AgNPs; L + P- was treatment with laser irradiation only; L - P+ was treatment with AgNPs only (control positive); L - P- was no treatment with laser irradiation or AgNPs (control negative). The growth of fungi had been monitored by measuring the optical density at 405 nm with ELISA reader. The particle size of AgNPs was measured by using (particle size analyzer) and the zeta potential of AgNPs was measured by using Malvern zetasizer. The PSA test showed that the particle size of AgNPs was distributed between 7.531-5559.644 nm. The zeta potentials were found lower than - 30 mV with pH of 7, 9 or 11. The reduction percentage was analyzed by ANOVA test. The highest reduction difference was given at a lower level irradiation because irradiation with a density energy of 6.13 ± 0.002 J/cm2 resulted in the biofilm reduction of 7.07 ± 0.23% for the sample without AgNPs compared to the sample with AgNPs that increased the biofilm reduction of 64.48 ± 0.07%. The irradiation with a 450-nm light source had a significant fungicidal effect on C. albicans biofilm. The combination of light source and AgNPs provides an increase of biofilm reduction compared to the light source itself.
    Matched MeSH terms: Lasers, Semiconductor*
  17. Effect of a single dose of low-level laser therapy on spontaneous and chewing pain caused by elastomeric separators
    Qamruddin I, Alam MK, Fida M, Khan AG
    Am J Orthod Dentofacial Orthop, 2016 Jan;149(1):62-6.
    PMID: 26718379 DOI: 10.1016/j.ajodo.2015.06.024
    The aim of this study was to see the effect of a single dose of low-level laser therapy on spontaneous and chewing pain after the placement of elastomeric separators.
    Matched MeSH terms: Lasers, Semiconductor/therapeutic use
  18. Fulltext Holistic management of venous ulcers especially with endovenous laser treatment using 980nm laser in an ethnically diverse society
    Murli NL, Lee TC, Beh ML
    Med J Malaysia, 2013 Dec;68(6):453-8.
    PMID: 24632912 MyJurnal
    AIM: Chronic venous ulcers usually occur as an occupational hazard due to venous insufficiency with venous hypertension. Endovenous laser treatment (EVT) is used to treat varicose veins with venous ulcers and outcome including demography assessed in the different races.

    PROCEDURE: 145 lower limbs(right 39.3%, left 60.7%) with venous ulcers involving reflux of the great saphenous (132 cases) and / or small saphenous (57 cases) veins underwent EVT with 980 nm diode laser for single (123 cases) or both (11 cases) legs intervention. Supplementary procedures required multiple avulsions and / or sclerotherapy. Holistic advice of multilayered bandaging, graduated compression stockings, weight reduction and lifestyle changes enforced.

    RESULT: The average age with venous ulcers was 53.6 years.The mean BMI was 26.8 : the Chinese, Indian and Malay BMIs were 25.1, 28.1 and 31.3 respectively. Symptoms that included pain, swelling, heaviness and cramps assessed pre- and postsurgically were significantly reduced (<0.0001), using the Wilcoxan signed rank test. Of the occupations involved by race, the Chinese were mostly salespersons, Indians blue collar workers and Malays foodrelated workers. Young overweight Indians with sedentary occupations were most predisposed to venous ulcers. Gram negative organisms 63.4% and gram positive organisms 36.6% were isolated in the ulcers. Most ulcers 63.5% measured <2 cm and majority 73.8% localised in the gaiter area.

    DISCUSSION: Results of EVT in healing ulcers with no recurrences more than 2 years were successful in 89.7% (130/145). Complications included numbness foot 7.5% and DVT 1.4%. 10.3% (15 cases) had recurrence of venous ulcers within 2 years. In terms of satisfaction 32.3% experienced as very satisfied while 63.4% were satisfied and 4.3% unsatisfied. In conclusion EVT is a useful adjunct with with minimal invasion in managing venous ulcers holistically.
    Matched MeSH terms: Lasers, Semiconductor
  19. The 808 nm and 980 nm infrared laser irradiation affects spore germination and stored calcium homeostasis: A comparative study using delivery hand-pieces with standard (Gaussian) or flat-top profile
    Ferrando S, Agas D, Mirata S, Signore A, De Angelis N, Ravera S, et al.
    J. Photochem. Photobiol. B, Biol., 2019 Oct;199:111627.
    PMID: 31536925 DOI: 10.1016/j.jphotobiol.2019.111627
    Photobiomodulation relies on the transfer of energy from incident photons to a cell photoacceptor. For many years the concept of photobiomodulation and its outcome has been based upon a belief that the sole receptor within the cell was the mitochondrion. Recently, it has become apparent that there are other photoacceptors operating in different regions of the electromagnetic spectrum. Alternative photoacceptors would appear to be water and mechanisms regulating calcium homeostasis, despite a direct effect of laser photonic energy on intracellular calcium concentration outwith mitochondrial activity or influence, have not been clearly demonstrated. Therefore, to increase the knowledge of intracellular‑calcium and laser photon interaction, as well as to demonstrate differences in irradiation profiles with modern hand-pieces, we tested and compared the photobiomodulatory effect of 808 nm and 980 nm diode laser light by low- and higher-energy (60s, 100 mW/cm2, 100 mW/cm2, 500 mW/cm2, 1000 mW/cm2, 1500 mW/cm2, 2000 mW/cm2) irradiated with a "standard" (Gaussian fluence distribution) hand-piece or with a "flat-top" (uniform fluence) hand-piece. For this purpose, we used the eukaryote unicellular-model Dictyostelium discoideum. The 808 nm and 980 nm infrared laser light, at the energy tested directly affect the stored Ca2+ homeostasis, independent of the mitochondrial respiratory chain activities. From an organism perspective, the effect on Ca2+-dependent signal transduction as the regulator of spore germination in Dictyostelium, demonstrates how a cell can respond quickly to the correct laser photonic stimulus through a different cellular pathway than the known light-chromophore(mitochondria) interaction. Additionally, both hand-piece designs tested were able to photobiomodulate the D. discoideum cell; however, the hand-piece with a flat-top profile, through uniform fluence levels allows more effective and reproducible effects.
    Matched MeSH terms: Lasers, Semiconductor
  20. Photobiostimulation effect on diabetic wound at different power density of near infrared laser
    Lau P, Bidin N, Krishnan G, AnaybBaleg SM, Sum MB, Bakhtiar H, et al.
    J. Photochem. Photobiol. B, Biol., 2015 Oct;151:201-7.
    PMID: 26313856 DOI: 10.1016/j.jphotobiol.2015.08.009
    The photobiostimulation effects of near infrared 808 nm diode laser irradiance on diabetic wound were investigated. 120 rats were induced with diabetes by streptozotocin injection. Full thickness punch wounds of 6mm diameter were created on the dorsal part of the rats. All rats were randomly distributed into four groups; one group served as control group, whereas three groups were stimulated daily with unchanged energy density dose of 5 J/cm(2) with different power density, which were 0.1 W/cm(2), 0.2 W/cm(2) and 0.3 W/cm(2) with different exposure duration of 50s, 25s and 17s, respectively. Ten rats from each group were sacrificed on day 3, 6 and 9, respectively. Skin tissues were removed for histological purpose. The contraction of wound was found optimized after exposure with 0.1 W/cm(2). Based on the histological evidence, laser therapy has shown able to promote wound repair through enhanced epithelialization and collagen fiber synthesis. Generally, irradiated groups were advanced in terms of healing than non-irradiated group.
    Matched MeSH terms: Lasers, Semiconductor
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