Although there have been many studies which proved the efficacy of ablative fractional erbiumYAGlaser as a successful method in treatment of HTS, no studies have assessed the efficacy of the combined approach of the erbiumYAGlaser and 5-FU in severe HTS treatment. For a topical agent to be active, it must first traverse the rate- limiting outermost barrier of the skin: the stratum corneum. The second mechanism used in this study was the micro- channels which were produced by the ablative fractional laser as a method of drug delivery. 18,19
No odontoblastic alterations have been noted, nor is there any inflammatory response in the pulp chamber beneath the preparation (Eversole and Rizoiu, 1995). Histopathologic studies in animals and humans have shown that pulpal tissues underlying deep cavity preparations made with an erbiumlaser do not undergo pathological changes. It was shown, utilising rats teeth, that fibroblast proliferation is observed sooner and more frequently in the specimens treated with the erbium:YAG laser than those prepared with the high-speed drill (Takamori, 2000). 4 Figure 5: Left: Waterlase MD. Right: Immediate post-surgery. Note: No
always correlate with high rate of recurrence . On the other hand, more aggressive approaches such as cryosurgery, electro-cautery and dermabrasion are used but recurrence is common if the damage is superficial and hypertrophic or hypopigmented scarring can occur if a significant proportion of reticular dermis is removed . In the last three decades, multiple modalities of laser treatment have been tried; however, very few studies reported comparative results. Based on selective photothermolysis, pigment-specific lasers can be used to achieve significant cosmetic improvement of dark epidermal nevi with a reduced risk of scarring, but successful treatment was not achieved in non-pigmented or keratotic lesions . Ablative lasers, such as CO 2 laser and erbium-YAGlaser have been
SSC sample was collected from Omdurman, Sudan. It was washed with distilled water many times to remove adhering soil and other contaminants then dried at room temperature after that it was milled. One gram of the sample was placed into a high-temperature glass beaker (Schott Duran—Germany) and it was burned on the air by the heat of Nd: YAGlaser (Dornier Medilas fiber to 5100) with an output power of 60 W for 30 s. The laser beam was delivered by single mode fiber optic with diameter 125 μm, the distance between the sample and the end of the fiber optic was 1 cm. Because of the small spot size of the laser beam, the process of burning was done point by point, the laser was fixed on a holder while the high-temperature glass beaker was rotated every 30 s carefully for ap- proximately 5 mm see Figure 1, this step repeated many times before investiga- tions for accuracy.
The experimental setup of the MBEFL is illustrated in Fig. 1. The MBEFL unit uses recycling technique of the backscattered Stokes as the SBS enhancing factor, subsequently amplified by erbium-doped fiber (EDF) and converted to electrical signal by the photodiode (PD). An external tunable laser source (TLS) is configured to emit maximum power of 13 dBm at 1550 nm is connected to this system via the 10% port of the Coupler (90/10 ratio) to provide the Brillouin pump (BP) source. An Isolator 1 was placed after the TLS to protect the device from any possible damage arising for reflected signals. Thereafter, the BP source is coupled with a 980 nm pump laser diode (LD) through a 980/1550 nm wavelength division multiplexing (WDM) coupler, and subsequently amplified via 10 m Erbium-doped fiber (EDF). The amplified signal is then launched into a 12 km dispersion shifted fiber (DSF), which is the Brillouin gain medium for the proposed work. In more details, the DSF made by is Lucent/AT&T with effective group index of 1.470 and an attenuation factor of 0.22 dB/km at 1550 nm, effective cross-sectional area of 86.6 µm 2 , and nonlinear
current consensus states that laser therapy should occur predominantly after surgery in large burn and traumatic scar patients. Consideration may be given if there is a role for laser pre-operatively to soften scar. It is important to have a stable, epithelized wound prior to laser therapy. Acne and surgical scars can be able to treated as early as 30 days. Recently, Drs. Ozog and Moy published a small clinical trial showing improvement of Mohs surgical scars treated with fractional carbon dioxide laser intra-opera- tively appeared to improve both appearance and texture . This warrants further investigation to determine if treating an early developing scar with fractional lasers may help minimize the ultimate scar. Large burn and traumatic wounds are treated with a collaboration of medical experts including acute burn surgeons, burn reconstructive surgeons, physical therapists, and laser surgeons. The optimal time to treat with laser scar resur- facing may vary patient to patient but appears to be months—1 year after the injury.
Laser lampau ungu (UV) telah digunakan untuk pelbagai aplikasi seperti dalam industri makanan, perubatan dan pergigian. Penggunaan laser dan sistem denyutan cahaya lain untuk fototerapi dan disinfeksi mikrob lain adalah berdasarkan ciri-ciri spektrum dan konfigurasi cahaya yang digunakan. Objektif kajian ini adalah untuk menggunakan laser Nd:YAG suis-Q pasif dipam lampu kilat bagi menyahaktifkan dua bakteria patogenik, iaitu Escherichia coli dan Listeria monocytogenes. Laser denyutan inframerah (IR) 1064 nm dan harmoniknya yong ke-2 dan ke-3 telah digunakan untuk menyinari Escherichia coli pada pelbagai nilai dos tenaga. Lampu UV gelombang selanjar (CW) 350 nm juga digunakan dalam proses menyahaktif bagi tujuan perbandingan dengan denyutan laser harmonik ke-3 (355 nm). Keputusan menunjukkan bahawa terdapat perbezaan statistik yang signifikan antara pengurangan log 10 purata bagi tiga panjang gelombang laser.
The quality of beam produced by a Q-switched Nd:YAG laser was investigated. A photographic technique associated with image processing system was utilized to determine the beam quality. The invisible light was detected using burn paper at various operation voltages of flashlamp driver in the range of 450 V to 900 V. The permanent record of the beam spots were made via a scanner and analyze using raster graphic or bitmap from a Matrox Inspector version 2.1 software. The line profile each of the beam spot produced an absorption spectrum. The amplitude of the spectrum indicates the depthness of the hole created after laser interaction with photographic paper. Meanwhile the width shows the beam size as well as the surface roughness. Thus the beam quality is illustrated by the depthness and the flatness of the beam spot. The flatter the surface the more uniform the laser beam distribution and the deeper the hole the more energetic the laser beam interacted with burn paper.
As discussed above, the laser light’s ablative energy must be delivered to the skin in a temporal pulse of appropriate duration in order to control skin heating and ensure the efficacy, efficiency and safety of treatments. In the case of a long laser pulse or continuous irradiation, the heat that is generated by the laser light has sufficient time to diffuse deeper into the tissue from the irradiated surface area. This results in higher thermal effects inside the skin. To generate high energy light pulses most devices use a standard PFN (Pulse Forming Network) technology. PFN pulses have a typical temporal shape with a slow rise time and a relatively long declining tail. The pulse power is not constant during the pulse and the exact pulsewidth is not defined. More advanced VSP (Variable Square Pulse)  technology generates pulses that provide much higher treatment precision, efficacy and safety [4-5]. A significant difference between the two pulse types is that for square pulses the average power and the peak power are nearly the same, which cannot be said for PFN-generated pulses. This means that the effect of VSP pulses on the skin is far more predictable than PFN pulses. This ultimately leads to superior treatment outcomes, with less discomfort for the patient and fewer side effects.
Photo-disrupter laser is the major class of ophthalmic lasers. It is a non-invasive method of performing posterior capsulotomy on an out-patient basis.  This solid state laser source emits an infra-red (IR) light invisible to the eye of 1064 nm wavelength. A red Helium-Neon(He-Ne) laser aiming beam is therefore incorporated into the instrument,  is aligned through the same optical pathway in the slit-lamp to allow accurate aiming of the beam.  The He-Ne laser is a low power gas laser producing a red beam.  The tissue disruption occurs at the focal point of the two laser beams.  The Nd-Yag L is a powerful continuous wave(CW) laser which is usually used Q-switched when treating the eye. Neodymium(Nd) ions produce the laser light and they are contained as impurity ions within an optically pure Yag crystal.  Solid crystals are usually pumped by incoherent light such as the Xenon arc flash lamp.  In this way a much higher concentration of active laser Nd ions can be achieved than in a gas laser medium.  Photo-disruption is a physical process known as optical breakdown, were by focused emitted laser energy of extreme intensity can be used to create such a strong electro-magnetic field that leads to molecular break-up. A strong local shock-wave results, which can be used in surgery to disrupt tissues.  If a large amount of energy is rapidly delivered into a tiny focal volume in a very short time, the constituent atoms of the target material will be ionized and disintegrate into a collection of electrons, ions and unionized atoms called a plasma at the focal point of Nd-Yag L with explosive expansion. This rapidly expands causing acoustic and shock waves which can disrupt tissue in the immediate neighborhood of the blast. The Q-switched Nd-Yag L is used in this way to disrupt posterior capsule.  A similar process occurs when lightning is followed by thunder in a storm and the atmosphere becomes ionized to a plasma state. Lightning occur as electrons rejoin their atoms. Thunder represents the resultant shock-wave created by this sudden energy release.  In Q-switched Nd-Yag L the duration of each laser pulse reduces to 10-20 nanoseconds,  this allow fierce ionization of the target tissue in the eye with creation of a flash, then a shock- wave results in photo-disruption of the molecules.  Laser releases a giant pulses of energy, when this pulse is focused to a 15-20 Mm spot, so that the nearly instantaneous light pulse exceeds a critical level of
Group 1also reveals a significant difference with group 2 and group 4 (p < 0.05), this might be due to the laser energy which was used for root apex surface treatment which leads to more microleakage, this is in agreement with Pashley, et al., who used different laser energies 11, 113 or 556 J/cm2. The two lowest laser energy levels increased permeability, whereas the highest produced a fully glazed surface that occluded
value of the TC (Figs. 4, 5). On the basis of the obtained data, it can be concluded that, in these two materials, the processes of heat transfer and heat distribution differ. For instance, in selective laser heating of ceramics, heat is consumed only on the melting of the material and on an insignificant change in the phase composition. During irradiation of compacts, heat is consumed on both melting and phase formation to a certain depth and on the formation of the sintering zone (Fig. 6 b, b’, c, c’). The ceramics and compacts differ substantially in porosity (and, hence, in density and thermal conductance). The compacts have a high porosity. This is why the values of the shrinkage and thicknesses of the melting– crystallization and sintering zones turn to be different (Fig. 9).
The experimental system used to validate the above model is shown in Fig. 4. A free-running Er:YAG laser (Fidelis Plus III, Fotona) is used to irradiate the water surface as it forms a quasi-ideal half-space. The focal point of the laser exit optics is located on the water surface with a spot diameter of 0.9 mm. A signal from a pulse generator triggers the laser system, also setting the pulse duration of the laser flash lamp (45 μs). The supply voltage for laser pumping has been set to 650 V. Resulting laser pulses are short (≈2 μs), causing generation of a single shock wave rather than several that are typical for longer pulses . The pulse energy was measured (Nova II, Ophir), where the mean value was 3.14 mJ with a std. deviation of 0.16 mJ. A piezoelectric sensor (CA- 1135, Dynasen) with a PZT-5A crystal disc of 1 mm in diameter was translated in parallel and perpendicular to the water surface using two linear stages with micrometer screws.
effect of HO-YAGlaser on the complete blood count the most crucial concern is the difference between the control and laser irradiation thus a paired t-test P<0.01 was used to evaluate the difference between the irradiated samples and non-irradiated control . For those with significant difference, the percentage of relative variance ( R.V.) was calculated to evaluate the extent of the relative change between irradiated and non-irradiated samples. All values are means ± SD .
Several studies over the years have shown that as IOP rises above 21 mm Hg, the percentage of patients developing visual field loss increases rapidly, most notably at pressures higher than 26- 30 mm Hg. A patient with an IOP of 28 mm Hg is about 15 times more likely to develop field loss than a patient with a pressure of 22 mm Hg. 7-8 It is recommended that the iridotomies are created using the lowest laser energy necessary to minimize complications.
A 23-year-old female had bilateral ureteral stents placed due to bilateral renal stones and hydronephrosis. The bilateral ureteral stents were changed every 3 months. A kidney ureter bladder (KUB) film showed left encrustation along the ureteral stent thus necessitating removal; however, the ureteral stent could not be removed cystoscopically. The ureteral stent was, therefore, extracted using flexible ureteroscopy (URS) with a holmium (Ho): yttrium aluminum garnet (YAG) laser.
Laser therapy is now an established treatment in many units for palliation of symptoms in patients with inoperable rectal cancer. It is effective in 80% and is a particularly gentle and safe treatment not requiring general anaesthesia and carrying a low risk of serious complications. The problem of the need for frequent follow up procedures is however a major one as this is inconvenient and sometimes distressing for the patient Laser treatment can be technically difficult, particularly in patients in whom the endoscope will not pass the stricture. It usually takes longer than with oesophageal tumours and constitutes a considerable workload. This small pilot study demonstrates promising results for the combination of laser and radiotherapy in rectal and rectosigmoid cancer. The treatments should be complimentary, laser to gain rapid relief of troublesome discharge and obstructive symptoms and radiotherapy to address the entire tumour bulk, and this appears to be confirmed. In addition endoscopic therapy has the advantage of pre-empting the obstruction which may result from radiotherapy. Both endoscopic and symptomatic results were impressive. Only two patients in this study failed to achieve long term functional success. The patient with the villous adenoma had a very extensive lesion which was initially 14 cm long and it was a notable success to control his troublesome rectal discharge at all. Even he had definite symptomatic and endoscopic benefit from additional radiotherapy and his general condition improved enough for him to undergo successful surgery. The reduction in follow up procedures to one every 42 weeks or so for C2 tumours and 9 weeks or so for C3 tumours is a useful improvement in follow up requirements. The reduction in laser energy per month required for good symptom control is another indicator which suggests benefit from radiotherapy. Only 12 of 32 patients referred with rectal/rectosigmoid cancer who received laser therapy during the 18 month period were entered into this study. We were reluctant to submit patients with very poor prognosis to a 2 week course of radiotherapy and the small proportion entered reflects the extent of disease and poor general condition in this elderly group who
Neodymium: Yttrium Aluminium Garnet (Nd: YAG) laser is used in the treatment of posterior capsule opacification (PCO) to improve visual acuity. PCO causes significant reduction in visual acuity in patients that had cataract surgery. This study is aimed at determining the visual outcome of patients who received Nd YAGlaser following PCO. The medical records of patients seen at the eye clinic of Ekiti State University Teaching Hospital, Ado Ekiti between January 2010 and June 2012 with the diagnosis of posterior capsular opacification (PCO) after cataract extraction and had Nd YAGlaser capsulotomy were reviewed. Demographic data, pre and post laser visual acuity, type of cataract surgery and the period of interval between surgery and diagnosis of PCO were extracted and analysed. A total of 90 patients (109 eyes) were seen over the study period. There was no sex predilection among the patients who developed PCO and were treated with Nd YAGlaser. Males were 47(52.2%) and females 43(47.8%) M:F=1.1. The age range of the patients was 17years to 87years. Most patients (77.8%) were in the 41-80years age range. Nineteen (21.1%) of the patients had bilateral eye involvement. A large proportion of these patients 59(65.6%) had the diagnosis of PCO between 3-12 months post- surgery. Majority of the patients, 67 (74.4%) presented with visual acuity of <3/60 (blindness) before the laser procedure while this reduced to 5(5.6%) post laser procedure. This study suggests that Nd YAGlaser procedure can improve distant visual acuity among patients with posterior capsular opacification. Keywords: Laser, posterior capsular opacification, visual impairment, cataract, complications.
ABSTRACT: Stainless steel as a welded joint has very important applications in industry. In this project, laser welding of stainless steel was studied at different values of laser power, pulse width and frequency, and keeping beam diameter as constant. A 9.9 kW ALPHA LASER AL200 Nd:YAG laser was used. The experiments were carried out in two sets on an SS430 ferritic stainless steel plate (100 x 100 x2.5 mm). Metallurgical and mechanical characterizations were carried to evaluate the weld beads. Macro and micro structural analysis is carried done to evaluate the bead profile and microstructures. Mechanical properties of the welded seam were evaluated by hardness and tensile strength testing. Durable joining was achieved only when the laser power is 2.2KW, Pulse width is 3.6 µs and Frequency is 14Hz. The Percentage of contribution found in ANOVA for each Process parameters were result of maximum tensile strength is based on the pulse width-41 percent and result of minimum hardness is based on the Power- 80 percent. The results of the various tests and examinations enabled definition of the best position for the incident laser beam with respect to the joint, for welding together the stainless steels. Microstructure revels that, it contains coarser ferrite grains with randomly distributed carbides. Due to laser beam welding and fast solidification. It forms dendritic grain structure in the outer portion of the weld, and equiaxed axial grains in the central regions of the weld
the fiberoptic handpiece, which allowed easy access to all recesses of the TMJ. No cher or debris exist because there is only minimal tissue damage. Clinical studies have demonstrated that the Holmium YAGlaser is a safe and effective modality for the delivery of energy in the TMJ 8 . When the laser surgery has been employed the benefits include the following: decreased operating time, increased precision, expanded accessibility, minimized blood loss, decreased hemarthrosis, non contact ability to vaporize pathology, reduced postoperative pain, and recovery time. Several success rates for TMJ arthroscopic surgery have been shown in the literature. In a multicenter retrospective study of 4,831 joints, after arthroscopic surgery 91.6% of all patients had good or excellent motion and 91.3% had good or excellent pain reduction 10 . Others reports in the literature showed success rates ranging from 76% 20 to 83% 5 for different arthroscopic procedures such as lysis and lavage or arthroplasty with disc repositioning. In our study we found a success rate of 93.3% with a significant improvement in pain reduction according with the VAS scores. The maximal interincisal opening improved from a mean of 25.95mm to 42.15mm after one year or more. No progressive changes were found on postoperative radiographs. Among the failed patients, two still showed significant pain after 24 and 27 months, respectively, and one did not show improvement in the range of motion, even though no pain was described. All three patients had diagnostic of osteoarthritis and synovitis. The mean of complications rate described in previous studies 10,15 was 3.8%, and included 5 th nerve deficit, 7 th nerve paresis, hearing loss, infections, and broken instruments. No complications were found in all patients who underwent arthroscopic surgery in our study.